US3079046A - Spout compensating loading gate control - Google Patents

Description

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Feb. 26, 1963 R. c. GoonwlN SPOUT COMPENSATING LOADING GATE CONTROL Filed Jan. 25, 1960 3 Sheets-Sheet 1 INVENToRs RALPH C. GOODWIN i BY GLb-x-C m A oRNEY gil Feb. 26, 1963 R. c. GooDwxN 3,079,046

SPOUT COMPENSATING LOADING GATE CONTROL Filed Jan. 25, 1960 3 Sheets-Sheet 2 INVENTOR RALPH C. GOODWIN MEL-C. M

ORNEY Feb. 26, 1963 R. c. GOODWIN sPoUT coMPENsATING LOADING GATE CONTROL 3 Sheets-Sheet 3 Filed Jan. 25, 1960 mhvs INVENTOR RALPH C. GOODWIN A RNEY- United States Patent G 3,079,046 SPOUT COMPENSATING LOADING GATE CONTROL Ralph C. Goodwin, Hamilton, Ohio, assignor to The Western States Machine Company, Hamilton, Ohio, a corporation of Utah Filed Jan. 25, 1960, Ser. No. 4,427 16 Claims. (Cl. 222-52) This invention relates to new and improved loading control mechanisms useful especially for regulating the introduction of charge materials into heavy cyclical centrifugal machines of the type used in the manufacture and the refining of sugar.

Various automatic mechanisms have been proposed heretofore for controlling or regulating the introduction of charge materials into heavy cyclical centrifugal machines of the type used in the manufacture and the refining of sugar, such mechanisms, in general, being adapted to initiate loading automatically, to hold a loading gate open at a set position as the basket becomes filled, and to close the gate, either after a preset period of time or when the basket charge has reached a certain final thickness. These known mechanisms are not able to keep basket charges uniform, especially in connection with the loading of sugar centrifugals, in that the charge material undergoes changes of fluidity during the processing of a given batch or run of massecuite or magma, by reason of temperature changes or continued crystallization or settling of crystals from syrup, and no two Ibatchesor runs have quite the same flow qualities. If the period during which the loading gate is held in its open position is determined on the basis of a preset time, ythe flow rate of the material through the open gate determines the change volume, rather than the control mechanism. On the other hand, if the control mechanism operates merely in response to the final charge thickness, the charges may still vary because substantially more or less charge material enters the basket after this response, depending upon the fluidity of the material and the distance -between the loading gate and the basket.

In more recently developed centrifugal loading` control mechanism, for example, as disclosed in United States Letters Patent No. 2,727,630, issued December 20, 1955, to Ioseph'Hertrich, the loading gate serving a centrifugal machine is provided with a power operated gate closing means serving both to `open and to close the gate; the centrifugal is provided with a charge measuring device that is changed in its position or condition of actuation as the volume of a basket charge increases in the course of a loading operation; and a progressive automatic coordination of the operation of these elements is brought about by means of a control mechanism that responds progressively to charge induced movements of the measuring device and in turn actuates the gate closing means progressively so as to bring the gate from a maximum open position to progressive closing positions corresponding to progressive positions of the measuring device until the' gate reaches a pinched or largely closed position asthe basket charge approaches a desired final volume', whereupon the gate closing means acts quickly to complete the closing of the gate so that the limited amount of material that can flow through the gate as it closes finally from the pinched position need not be enough to cause an objectionable deviation from the desired final charge volume. The charge measuring device of a centrifugal loading control mechanism as disclosed in the above identified patent has provisions for manually adjusting the maximum opening of the loading gate and the thickness of the charge in the basket at the moment when progressive closing of the gate commences; the final thickness or volume of the material charge in the centrifugal basket; and the pinched or largely closed position of the loading gate, that is, the position of the gate when progressive closing thereof is concluded and quick final closing of the gate occurs. By reason of the foregoing manual adjustments, the `described centrifugal loading control mechanisms can be adapted to control the loading of various charge materials into the associated centrifugal, and to cause such loading to be eciently conducted so long as the ow properties of the charge material are known in advance and do not vary considerably during the loading operations so that suitable adjustments can be effected in the control mechanism based upon the known properties of the charge material. Since the flow rate through the loading gate will vary with changes of the hydrostatic head or level of charge material awaiting delivery through the loading gate, one of the centrifugal loading control mechanisms disclosed in `the above identified patent includes pressure responsive means connected with the loading control mechanism and with the tank holding the charge material and which' respond to changes of the hydrostatic head of material in the tank to adjust the relationship of the loading control mechanism to the position of the loading gate so as to increase the opening of the gate at any stage of the loading operation as the level of material in the tank falls, and so as to decrease the gate opening upon a rise' of that level. Thus, the described mechanism seeks to maintain etiicient loading operations at all times, that is, to maintain the greatest possible iiow rate through the open gate for achieving loading of the centrifugal in theA least possible time, by compensating automatically for changes in the flow rate that would result from changes in the hydrostatic head or level of the charge material awaiting delivery, without requiring the use of the previously mentioned manual adjustments.

However, as previously mentioned, the charge material undergoes changes of fluidity during the processing of a given batch or run of massecuite or magma, by reason of temperature changes or continued crystallization or the settling of crystals from syrup, and no two batches or runs have quite the same fiow qualities, so that, even if the opening of the gate is automatically varied in accordance with changes in the hydrostatic head or level of charge material awaiting delivery through the loading gate, the flow rate through the gate may still vary substantially by reason of such changes of fluidity.

Moreover, where mechanisms of the same constructions must serve for loading charge materials differing greatly in viscosity, such as, a very thin or soupy massecuite atvone time and a heavy, highly viscous massecuite at another time, a given extent of initial opening of the loading gate may allow the massecuite to spout over the basket in one case but still be insufficient for efficient loading of the basket in the other case.

By reason of the above mentioned deficiencies, the existing automatic loading control mechanisms are incapable of simulating the efiicient loading conditions attained by a proficient operator exercising manual control over the opening of the loading gate. When the gate is under manual control, it is the usual practice to open the gate an initial amount so as to permit the flow of charge material to be established. The operator then determines the character of the established flow by observation of the latter, and then further opens the gate to the position which experience has taught is the optimum for the observed ow conditions.

Accordingly, it is a principal object of this invention to provide automatic loading control mechanism for heavy cyclical centrifugal machines or the like which are capable of simulating the optimum Aloading conditions achieved with manual control by a proficient operator.

Another object is to provide loading control mechanisms for heavy cyclical centrifugal machines or the like which accurately regulate the successive loading operations and which enable the substantially uniform charging of cyclical centrifugal machines in successive loading cycles notwithstanding changes occurring in the fluidity of the charge material or in the hydrostatic head or depth of charge material in the supply tank from which the material is delivered into the centrifugal machines, thereby to avoid uncontrolled differences in ow rate as a result of such changes which would objectionably influence the uniformity of loading operations.

Another object is to provide loading control mechanisms of the described character which are not adversely influenced yby only temporary or localized changes in the viscosity or fluidity of the charge material in the supply tank, for example, by the tendency of the massecuite to settle against the gate plate between loading cycles and thereby form la slight partial plug that has to ooze out of the gate when the laater is initially opened before normal ilow is established.

Among other objects of this invention are: to provide loading control mechanisms which are automatically adjusted so as to avoid uncontrolled changes in the now rate through the gate as a result of changes in the viscosity or uidity of the charge material or changes in the hydrostatic head or depth of charge material in the supply tank, or a combination of such changes, and which can be applied to any existing heavy centrifugal installation with little mechanical alteration of the installation; -to provide such mechanisms which are useful for the controlled loading of many diifer'ent types or grades of charge material, and under any desired process conditions; and to provide such mechanisms which have simple and easily accessible adjustments for adapting the opera tion of the mechanism to the processing requirements of any material for which it may be used;

In accordance with an aspect of this invention, the control of the opening of the loading gate is modied or compensated in accordance with the pressure conditionl existing in the spout ofthe supplyl tank or mixer so that, when the gate is closed, such pressure condition represents the hydrostatic head in the supplyV tankand determines the extent vof the initial opening of the gate at the commencement of a loadingl operation, and, when the gate is opened, the pressure condition existing in the stream of the charge material fiowing through the spout causes further opening of the gate to a maximum extent primarily dependent upon the viscosity of the charge material in order to obtain a controlled now rate of the charge material into the centrifugal machine or the like.

In a preferred embodiment of the inventiom a centrifugal loading control mechanism of the kind disclosed in the above identified United States Letters Patent No. 2,727,630, which includes a power operated gate opening and closing means for the loading gate serving a centrifugal machine, a charge measuring device that tis changed in its position or condition of actuation as the volume ofl a basket charge increases in the course of a loading operation, and a control mechanism which brings about the progressive automatic coordination of the operation of the power operated gate closing and opening means and of the charge measuring device and which responds progressively to charge induced movement of the measuring device and in turn actuates the gate closing means progressively so as to bring the gate from a maximum or initial open position to progressive closing posia tions corresponding to progressive positions of the measuring device, and which has an adjustable stop element as a part of its charge measuring device for varying the initial open position of the gate, is further provided with means located in the spout leading to the loading gate for sensing the pressure condition existing in the charge ma terial in the spout, and with means responding to the sensed pressure condition to automatically actuate such adjustable stop element in Order to maintain a controlled now rate irrespective of changes in the iiuidity of the charge material or changes in the hydrostatic head of the charge material awaiting delivery through the loading gate.

A further object of the invention is to provide an ar-4 rangement for sensing the pressure Within the spout of the supply tank or mixer by means of a pipe probe opening into the spout, while avoiding plugging Vof the pipel probe by the charge material so that the probe will con tinue to reliably sense the pressure within the spout for the purpose of compensating the operation of the loading gate control mechanism.

In accordance with another aspect of this invention, the pipe probe is purged by a nowv offwater' from a restricted flow source in order to avoid plugging of the pipe probe by the charge material, andthe pressure condition in the spout is transmitted through the Water lilling the pipe probe and actuates a valve device establishing a corresponding pneumatic signal which controls lthe positioning of a pneumatically operated device connected to the adjustable stop element of the charge measuring device. Thus, the stop element of the charge measuring device is continuously adjusted in accordance with the pressure condition in the spout for varying the initial and maximum open positions of the gate, and the force available for adjusting the stop element, or for maintaining the latter in an adjusted position, may be independent of the pressure condition sensed in the spout of the loading tank ,by reason of the force amplification possibilities inherent in the valve device, which converts the water pressure signal into a pneumatic signal, and in the pneumaticallyoperated positioning device controlled by such pneumatic signal.

A further feature of the invention is the provision of a detlector baille along the lower edge of the plate of a` loading gate having a control mechanism which is compensated in accordance with the pressure condition in the spout of the supply tank, with such baille acting to det-lect the stream of charge material downwardly into the basket of the centrifugal particularly when the gate opening is small in response to a high hydrostatic head of soupy or highly fluid charge material in the supply tank which would otherwise produce a dat trajectory of charge material pouring from the gateV and splashing over the curb of the centrifugal.

The above,A and other objects, features and advantages of the invention, will be apparent in the following detailed description of illustrative embodiments thereof which is to be read in connection with the accompanying drawings forming a part hereof, and wherein:

BIG. 1 is a diagrammatic assembly view of a cyclical centrifugal installation provided with an automatic loading control mechanism having compensating means responsive to the pressure in the spout of the supply tank in accordance with the invention;

FlG. 2 is an enlarged sectional view taken along line 2 2 of FIG. 1 and showing a pipe probe used for sensing the pressure in the spout;l

FIG. 3 is an axial sectional view of a valve device included in the compensating means of FIG. l;

FIG. 4 is an axial sectional view of a pneumatically operated positioning device also included inA the Compensating means of FIG. l;

B1G.V 5 is a view similar to that of FlG. l,v but showing another embodiment of the invention; and

FIG. 6 is an axial sectional view of a pneumatically operated positioning device included in the embodimentof FIG. 5.

Referring to the drawings in detail, and initially to FIG. l thereof, it will be seen that this diagrammatic view is a composite o-f elements shown in plan view at the right hand side of the ligure and other elements shown in ele` vation at the left hand side of the' ligure. At the right hand side, the reference numeral 1 denotes a portion of the sidewall of a filtering' centrifugal basket of the type used in the processing of sugar. A portion of an annular basket charge, for example, of sugar or other granular solids, is indicated at 2. The inner surface of the complete charge is indicated atV 2b, while broken line 2a indicates a. position through which the charge surface progresses inward in the course of a loading operation.

At the left hand side of FIG. 1, there is shown a portion of a supply tank or mixer 3 holding charge material to be delivered into the centrifugal basket 1. The material flows from this tank through a loading spout 4 and thence into the basket when a loading gate 5, of any suitable construction, is moved away from its position closing; the spout outlet. Gate 5 is connected by suitable linkage, including a link 6, arm 7, gate' operating. shaft 8 and arm 9, with the reciprocatory plunger of an air cylinder 10 which serves as a motor both for opening and for closing the loading gate.

It will be evident that, when air under suitable pressure is admitted into the upper part of cylinder 10 through a conduit 11, the arms 9 and 7 on shaft. 8 are rocked counter-clockwise,` as viewed in FIG. l, so as to lift gate 5 to an open position, and thereby to per-mit charge material in tank 3 to flow under the influence of gravity through the outlet of spout 4 into basket 1; while the admission of air under pressure through a conduit 12 into the lower end of cylinder 10, conduit 11 then being suitably vented, brings about a closing movement of loading gate 5.

It is well known that the opening of loading gate 5 should take place after the basket 1 of the cooperating centrifugal machine has .been emptied and brought to a low speed of rotation suicient to cause the formation of. an even annular wall of the inflowing charge material under the centrifugal force imparted to it by the basket rotation. Further, it will be understood that the formation of a complete charge in the basket requires a considerable period of inflow of the charge material, for example, 10 to 30 seconds, more or less, depending upon the volume of the charge to be treated in the centrifugal, the size and extent of opening' of the loading gate, and the ow rate of the charge material.

As t-hecharge material ows into the basket, the annular wall of charge material being formed in the' basket increases gradually in radial thickness until it reaches a nal thickness corresponding to the desired charge volurne, at which point the loading gate should be closed. This progressive building up of the charge is susceptible to measurement in various ways. A particularly simple yet effective way of measuring the thickness of the charge in the centrifugal basket, as-is well known, is to use a charge feeler that slides on and is moved inward by the rotating inner surface of the increasing charge. -Such a charge feeler is illustrated at 15 in FIG. 1 and is carried by, and swings with, a shaft 16 mounted by a suitable bearing and bracket arrangement on or adjacent to the usual stationary curb (not shown) of the centrifugal machine.

The arrangement embodying the present invention for modifying the extent of opening of loading gate 5 in accordance with the ow rate of the charge materialthrough spout 4l is particularly suited for use wit-h a centrifugal loading control mechanism ofthe kind disclosed in United States Letters Patent No. 2,727,630, issued December l2O, 1955, to Joseph Hertrich, and which, as shown in FIG. l of the drawings, comprises two coordinated assembly units and 40 interconnected by suitablelink means 17.

Unit 20 includes' thefeeler shaftV 16 and chargefeeler 15, and serves to integrate the charge measuringv and. ad.- justment functions of the control mechanism. Unit 40' includes a reciprocable support 41 rockably mounted on a fixed pivot 42 located in suitable relation to the gate operating mechanism. A link 18 is pivotally connected, at 43, with support 41 and, at 44, with the gate operating a-rm- 7 on shaft 8,.. so that support 41. moves.v vforwardly and rearwardly about pivot 42 in. response to opening and closingr movements of loadingU gate Y5. v

As is described in greater detail in the above identified patent, reciprocable supportl 41- carries an-air valve 45 for controlling the supply of compressed air to the gate oper# ating motor or air cylinder 10 and having a plunger 46 normally biased, by acompression spring 47, to a gate opening position, but which is movable backward from that gate opening position, rst to a gate inactivating position and then to a gate closing position at the backward limit of such movement.

The several operative positions of air valve 4'5v are determined bythe positioning of a control member' 48 which is arranged for movement with the reciprocable support' 41', so asl to be carried with the support in the forward and backward movements of the latter, andl yet ismovable relative to the support 41 in order to position the valve plunger 46.

The lower end of control member 48 projectsv down# ward from support 41 for pivotal connectiomat 49, with one end of the interconnecting link 17. Link 17 extendsA from unit 40 for pivotal connection, as atv 19, withl a lever armA 21 on the feeler shaft 16 of unit 20. The' upper end of control member 48 is arranged to be positioned? by' the armature or plunger of a solenoid 50 which is fixed to support 41 so that control member 48 is thrust forwardly when the solenoid is energized.

A tension spring 51 is connected between support 41` and an upper part of control member 48 so as to bias' the latter in the direction for moving valve 45 to its gate closing position whenever solenoid 50 is deenergized, and this spring 51- is strong enough to overcome the force of valve spring 47. Another tension spring 52Y is connected between the lower part of control member 48 and sup port 41 so as to yieldably connect control member 48 and uni-t 20 for movements with support 41 in response tofmovements of loading gate 5.

Control member 48 is held in a' stable working' position relative to valve plunger 46, the armatureV of solenoid 50 and tension springs 51 and 52, by means of a pin and slot connection with a reciprocable shaft 53 carried by support 41'. The forward end of shaft 53 is connected with a manually' operated lever 54 through suitable linkage 55, so that the control mechanism can be operated by hand to bring about opening and closing movements of the loading gate. A stable normal position of shaft 53 ismaintained by means of a compression spring 56 which surrounds shaft 53 and bears, at its opposite ends, against collars on the shaft engageable with pins on shaft 53 and parts of support 41 so that aforce suicient to overcome the compression of spring 56 must be applied by way of the lever 54 inorder to slide shaft 53 either backwardy or forward relative to support 41.

By reason of the pin and slo't connection between control member 48 and shaft 53, the control member is free to undergo its pivotal control movement relative to support- 41 so long as shaft 53 is in its normal position determined -by spring 56. However, shaft 53 can be manually moved to an extent exceeding the lost motion provided by such pin and slot connection thereby to effect manually induced movements of control member 48 for actuating the plunger of valve 45 to and from any' of its operating positions, that is, its gate closing, gate inactivating and gate opening positions.

The operation of unit 40 will nowv be summarized:

If solenoid 50 is deenergized, spring 51 holds controlmember 48 and air. valve 45 in gate closing position, so thatv compressed. air from a line 57 passes through valve- 45. into conduit 12while conduit 11. is vented. through the valve, whereby air cylinder 10 moves loadingl gate 5 to its closed position or hold the gate inthat position.

When solenoid 50 isl energized, its armature thrusts the upper` end of control member 48 forward. againstV the; tension of spring 51 and, if the lower end of control member 48 is then being held in a forward position by spring=52 or link 17, control member 48 and air valve 45 are disposed in gate opening position. The compressed air from line 57 now passes into conduit 11, while conduit 12 is vented, so that cylinder 10 starts moving loading gate to its open position. As the gate moves open, its operating arm 7 acts through link 18 to rock support 41 forward about its pivot 42. Control member 48 and link 17 move forward with support 41, thus allowing solenoid 50 to keep control member 48 and valve 45 in gate opening position, unless and until a limit or restric- -tion is imposed against the forward movement of link 17 and hence of control member 48.

' If, while the gate is opening, a resistance is applied through link 17 to limit the forward movement of member 48 with support 41, a further increment of forward movement of the support causes a relative backward movement of the lower end of member 48 to dispose -this member and air valve 45 in gate inactivating position. The air valve 45 then seals oi both conduits 11 and 12, so thatl air cylinder 10 holds the loading gate in whatever position it occupied at the moment of such shifting or relative backward movement of control member 48. Moreover, if the lower end of control member 48 is now given a further backward movement relative to support 41 by action' transmitted through link 17, it will dispose the air valve 45 in gate closing position and cause air cylinder 10 to start closing movement of the gate. However, a corresponding backward movement of support 41 accompanies the closing movement ofthe loading gate and will again dispose member 48 and air valve 45 in gate inactivating position with respect to the pivoted support, unless a further backward movement of link 17 and the lower end of member 48 has occurred meanwhile through further action on link 17.

It will be evident, therefore, that the opening of the loading gate and the resulting forward movement of unit 40 produces a corresponding forward movement of link 17 which, through lever arm 21 and shaft 16 of unit 20, will cause the outward movement of feeler to a working position in desired relation to basket wall 1; that by limiting the forward movement of link 17 the extent of the initial gate opening can be predetermined, the gate motor' 10 being inactivated` to hold the gate at the selected extent of the initial opening when such limit is reached; andthat the closing movement of the gate can be brought about progressively through progressive backward movement of the lower end of control member 48, in direct proportion to that movement. Fur-ther, it will be evident that the progressive inward movement of feeler 15, as induced by a progressively increasing charge in the centrifugal basket 1, can act through shaft 16, lever arm 21 and link 17 to cause progressive backward movement of the lower end of control member 48 and, in this way, to cause closing movements of the loading gate proportional to the increasing thickness of the basket charge.

Referring more particularly to the construction of unit 2t) of the existing centrifugal loading control mechanism, it will be seen from FIG. 1 that lever arm 21 is not fixed directly to feeler shaft 16 but is connected for rotation with this shaft and teeler 15 through a rotary member 23 and an underlying lever arm 24 which is fixed to shaft 16. Lever arm 24 has a yieldable and adjustable connection with member 23 through a tension spring 25 interconnecting these elements and an adjustable set screw or stop element 26 which is threaded in arm 24 and bears against an abutment formed on member 23. Member 23, in turn, has a yieldable and adjustable connection with lever arm 21 through aftension spring 27 interconnecting these elements and an adjustable set screw or stop element 28 which is threaded in arm 21 and bears against an abutment on member 23. The above -described connections between parts 21, 23 and 24 cause these parts as well as shaft-16 and feeler 15 to tend to move together 8 about the axis of shaft 16. However, being yieldable, these connections prevent damage to the mechanism in the event of any obstruction of the feeler movement or of the movement of arm 21.

The unit 20 further includes an adjustable stop element 29, which, in the embodiment of the invention illustrated in FIG. l, is in the form of a radial cam having a spiralshaped periphery and which is fixed to a rotatable shaft 30 in a position to be engaged by an abutment 23a on member 23 when the loading gate 5 has been moved to an initial gate opening.

Unit 20 also preferably includes a relatively iixed limit switch 31 having a movable switch arm 32 which cooperates with a switch operating lobe 23b on member 23 to bring about quick closing of the gate in the manner hrieiiy described hereinafter. ri`he limit switch 31 has contacts connected electrically in a control circuit leading to solenoid 50, and is employed so as to hold the solenoid in energized condition in the course of each loading operation.

The operation of unit 20 of the illustrated existing cen' trifugal loading control mechanism is briefly summarized as follows:

It will be evident that forward movement of unit 40 and link 17 in response to opening movement of loading gate 5 causes lever arm 21 and member 23 to move counter-clockwise about the axis of shaft 16 until abutment 23a on member 23 engages against the adjustable stop element 29. When that occurs, feeler 15 ceases to move outward and link 17 and the lower end of control member 48 cease to move forward with support 41 whereupon control member 48 and air valve 45 are shifted to gate inactivating position and further opening of the loading gate is discontinued. Thus, adjustable stop element 29 determines the extent or height of the initial gate opening.

The adjustable stop element 29 also acts, along with the stop 26, to control the initial position of feeler -15, that is, the position occupied by the feeler at the limit of the gate opening movement and, hence, the thickness to which an incoming charge in basket 1 must build up before the charge begins to act upon feeler 15 for moving the latter inward away from the basket wall. i

When feeler 15 is moved inward by the charge building up within the centrifugal basket, shaft 16 and lever arm 24 are turned clockwise, as viewed in FIG. l, and the engagement of stop 26 with the abutment of member 23 causes similar turning movement of the latter which is communicated to lever 21 by way of spring 27. Such turning of arm 21 acts through link 17 on control member 48 to move the latter and air valve 45 to gate closing position. Since feeler 15 is moved progressively inward by the charge, link 17 continues to act in the backward direction on control member 48 so that, as previously described, the closing movements of loading gate 5 are proportionate to the increasing thickness of the basket charge.

Such progressive closing movement of the gate in accordance with inward movement of feeler 15 continues until the loading gate has reached a desired pinched or largely closed position, whereupon switch operating lobe 23h of member 23, which moves arm 32 and limit switch 31 to circuit closing position as member 23 turns in response to opening movement of the loading gate, is moved to a position releasing arm 32 and thus causing the contacts of limit switch 31 to open. At that moment, solenoid S0 is denergized, and control member 4S and air valve 45 are immediately shifted to gate closing position so as to close the loading gate quickly without further dependence upon the position of feeler 15. Although the position of member 23 at the moment of final gate closing is always tixed by reason of the fixed position of limit switch 31, adjustable stop element 26 provides for any desired adjustment of the relative position of feeler 1S and member 23 and thereby determines the position to be occupied by feeler 15 at the moment when limit switch 31 .9 strips for causing quick closing of the gate. Hence, adjustable stop element 26 determines the thickness to which the incoming charge will build up on the wall of basket 1, that is, the final charge thickness, before the gate is closed completely.

The adjustable stop element 28 provides for relative adjustment between lever arm 21 and member 23 and thereby determines the position of loading gate at the moment quick closing starts, that is, the pinched loading gate position, or the height of the final gate opening at which the quick closing action will occur.

In the above described existing centrifugal loading control mechanism, the adjustable stop element 29, which is shown in FIG. 1 in the form of a radial cam, may be manually adjusted before the commencement of loading operations in order to vary the initial opening of loading gate 5. Thus, assuming that the charge material in tank 3 has a uniform or constant fluidity and a constant hydrostatic head, then the flow rate of the charge material into basket 1 will be largely determined by the setting of stop element 29.

However, as is well known, the charge material undergoes changes of uidity during the processing of a given batch or run of massecuite or magma, by reason of temperature changes or continued crystallization or the settling of crystals from syrup, and no two batches or runs have quite the same ow qualities. Further, as charge material is progressively removed from tank 3, the hydrostatic head or level of charge material awaiting delivery to the centrifugal progressively decreases, and such changes in uidity of the charge material and in the hydrostatic head or level of the charge material serve to vary the flow rate for each opening of the loading gate. If the opening and closing of the loading gate are responsive only to the build-up of charge material in the basket, such variations in the ow r'ate objectionably influence the uniformity of loading operations. With the described existing centrifugal loading control mechanism, the desired uniformity of the loading operations can be obtained only through manual adjustment of stop element 29 during the course of the loading operations, but this requires supervision of the loading operations by skilled personnel and detracts from the desired automatic operation of the loading control mechamsm.

In accordance with the present invention, adjustable stop element 29 is automatically actuated so that, if the ow rate is relatively small, by reason of a highly viscous charge material or a relatively small hydrostatic head of the charge material in tank 3, stop element 29 is adjusted in the direction for increasing the opening of gate 5, whereas, if the llow rate is relatively large, by reason of a soupy or highly lluid charge material or a large hydrostatic head of such charge material in tank 3, stop element 29 is adjusted in the opposite direction for decreasing the extent of thegate opening.

Such automatic actuation of stop element 29 is made responsive to a pressure condition sensed at a suitable point A in spout 4, with the sensed pressure being the static head at point A when there is no flow through the spout, for example, as a result of complete closing of the gate, and with the sensed pressure being a. combination of the static head and velocity head at point A when gate 5 is opened and there is a flow of charge material through spout 4.

It will be apparent that, when there is no flow through spout 4, the pressure sensed at point A is determined exclusively by the hydrostatic head of charge material in supply tank 3. However, when gate 5 is opened and the charge material ows through spout 4, the static head at point A is reduced by reason of the conversion of a part of the static head into -a velocity head, and the combination of the static head and velocity head is always less than the pressure sensed at point A with the gate closed by reason of the losses involved in the conversion of static head into velocity head, such losses being due to friction. resist` ing the ow of charge material through lspout 4 and the restriction of the flow from tank 3 into the spout. Thus, the static pressure at point A decreases as the hydrostatic head of charge material in tank 3 decreases, and, when there is a flow of charge material through spout 4, the combined pressure at point A further decreases by an amount -depending primarily upon the viscosity of the .charge material.

As shown in FIGS. 1 and 2, the pressure 4at point A in spout 4 is preferably sensed by a pipe probe 60 which is formed of a length of bent tubing and has a threaded bushing `61 on one end received in a suitably tapped opening in the side of spout 4. The free end of pipe probe 60 has a plug therein formed with a small opening or hole 62. The pipe probe l60 is preferably turned so that the opening 62 faces more or less toward the end of spout 4 communicating with supply tank '3 and therefore senses a velocity head resulting from the ow of charge material through the spout as well as the static head in the spout at point A. Since the drop in the sensed pressure due to the friction of iluid flow, that is, the pressure loss due to viscosity, increases along spout 4 from the end adjacent tank 3 to the end carring gate 5, it is apparent that the sensitivities to changes in the hydrostatic head of charge material in tank 3 and to changes in the lviscosity of the charge material ilowing through spout 4, respectively, may be relatively adjusted by locating pipe probe 60` either closer to, or further away from, the end of spout 4 adjacent tank 3.

It is also to be understood that rotation of the probe greatly aiects the sensitivity thereof to the velocity head component. Thus, when opening 62 faces directly upstream, the probe 60 senses the whole velocity head component, whereas, when opening `62. faces at right angles to the direction of dow, the probe picks up none of the velocity head and, when the opening of the probe faces downstream, the velocity head component is negative, that is, subtracted from the statichead sensed by lthe probe.

In the illustrated embodiment of the invention, the pressure at point A in spout 4 sensed by pipe probe .60 actuates a valve device 70 (FIGS. 1 land 3) which establishes a `corresponding pneumatic signal controlling a pneumatically operated positioning device 100 (FIGS. 1 and 4). The positioning device 100 is connected to the shaft 30 ofthe cam-shaped stop element 29 and is effective to dispose the latter in 'an angular position deterrnin-ing the initial or maximum opening of gate 5 which corresponds to the pressure sensed by pipe probe 60.

Referring to FIG. 3 in det-ail, it will be seen that the valve device 70 may include a valve body 71 having an axially extending bore in which a valve plunger 72 is `axially movable. The valve body 71 has 4a port 73 for connect-ion with a regulated compressed -air supply line 74, and an outlet port 75 which is spaced from the port 73 in the axial direction of body 71 and which is intended for connection to a line or conduit 76 transmit:` ting the pneumatic signal from valve device 70 to the positioning device `100 and having a controllable air bleedl 77 extending therefrom (FIG. 1).

The plunger 72 of valve device 70 has spaced sealing pistons 78 and` 79 defining an annular space 80 therebetween, and the sealing piston 78 is .axially disposed on the plunger to more or less cover port 73, depending upon the position of the plunger, yfor thereby controlling the rate at which compressed air can ow from port 73, through annular space 80 into port 7S. It `is apparent that the air pressure or pneumatic signal transmitted through line 76 to positioning device 100 depends upon the irate at which the regulated compressed air supplied to valve device 70 is permitted to flow from port 73 to port 75. Thus, when plunger 72 is displaced toward the righ-t, as viewed in FIG. 3, so that piston 78 pro`v ygressively uncovers port 73, the pneumatic signal or air pressure inline 76 is correspondingly increased, whereas.

when plunger 72 is displaced toward the left to progressively close port 73, the magnitude of the pneumatic signal is correspondingly reduced and the air bleed 77 permits the pneumatic signal in line 76 to drop rapidly in response to such displacement of plunger 72 toward the left.

In order to position valve plunger 72 in accordance with the pressure sensed yby pipe probe 60, valve device 70 Ifurther includes heads 81 and `82 at the opposite ends of valve body 71 and having covers y83 and 84 secured thereto, for example, by lbolts `85. The confronting faces of head 81 and cover S3 are formed with mating recesses which form chambers 86 and 87, respectively, and a flexible diaphragm 88 separa-tes chambers 86 and 87 and is clamped, at its periphery, between the confronting faces of head `81 and 83. Similarly, the confronting faces of head 82 and cover 84 are formed with mating recesses dening chambers 89 and 90, respectively, which are separated by a ilexibie diaphragm 91 having its periphery clamped between head 82 and cover 84. The diaphragms =88 and 91 have back-up discs 92 and 93 secured thereto by central bolts 94 and related nuts 95, and the heads of the bolts 94 bear against the adjacent ends of valve plunger 72. The ratio of the effective areas of d-iaphragms 88 and 91 is determined by the inner diameter of a replaceable ring 89a iitted in chamber 89 to establish the effective bore of that chamber, and also Vby 'the diameter of the back-up disc 93 associated with the diaphragm 91.

The chambers 86 and 89 are preferably vented to the atmosphere, as at 97, so that the movements of diaphragms 88 and 91 are not resisted by air trapped within such chambers. The pressure sensed by pipe probe 60 is transmitted to chamber 87, in the manner hereinafter described in detail, to act against diaphragm 88, and thereby tend to move plunger 72 toward the right, as viewed in FIG. 3. The pneumatic signal or air pressure in line 76 is fed to chamber 90, for example, by way of a line 98 branching off from line 76 and opening into chamber 90 through -a port `99 in cover `84, so that the pneumatic signal or air pressure acts in chamber 90 against diaphragm 9.1 and tends to move valve plunger 72 toward the left, as viewed in FIG. 3. Thus, valve plunger 72 always seeks a position where the force due to the pressure sensed by probe `6() and transmitted -to chamber 87 is equal to the force due to the pneumatic signal which is transmitted to the chamber `90. It is apparent that any change in the sensed pressure transmitted to chamber I87 causes a displacement of valve plunger 72 in one direction or the other until the pneumatic signal or air pressure inline 76 corresponds to the changed sensed pressure. Further, by suitably selecting the inner diameter of ring `89a in chamber 89 and the diameter of back-up disc 93, it is possible to vary the ratio of the pneumatic signal established in line 76 and the corresponding sensed pressure transmitted to chamber 87.

In order to avoid plugging or clogging of pipe probe 46i) by the charge material in Isupply `tank 3, a purging flow of water is preferably maintained through opening 62 of pipe probe 60 into spout 4, and the pressure sensed at point A in spout 4 is then transmitted through such water to chamber 87 4of valve device 70. For lthis purpose, bushing 61 of pipe probe 68 is connected to a line `63 which opens into chamber 87, yand a ilow of 4Water is ysupplied from a source of regulated pressure through a pipe 64 which also opens into chamber 87 and which has a restriction 65 interposed therein in order to ensure a slow flow of water through pipe 64, chamber S7 and pipe 63 for keeping clear the opening of pipe probe 60. rlhe :restriction `65 also ensures that the pressure acting in cham-ber -87 will be that transmitted from pipe probe 60 rather than the regulated pressure supplied to pipe 64, and it is only necessary 4that the Vregulated pressure should be greater than the maximum pressure that may be sensed by probe 60. Since pipe probe 60, pipe 63 and chamber 87 are continuously lled with water, it is apparent that any change in the pressure sensed at the opening 62 of the pipe probe is transmitted through the water to chamber 87 for action against diaphragm 88.

The pneumatically operated positioning device controlled -hy the pneumatic signal fed thereto from valve device 79 by Way of line 76 is eifective to dispose stop element 29 in a position corresponding to the pneumatic signal, and may Ebe of a type that moves the stop element to its adjusted position or maintains the s-top element in the adjusted position -with a force that is independent of the magnitude of the pneumatic signal. A suitable commercially available positioning device is that known 'as a Cylinder Conomotor which is produced by the Cono- 4flow Corporation of Philadelphia, Pennsylvania. Such a device generally includes a cylinder -101 pivotally mounted, at 102, on a zbracket 103 which is secured to the frame or base of charge measuring unit 20 (FIG. 1). Cylinder 101 contains a reciproca-ble piston 104 (FIG. 4) which has -a stem 10S extending laxially therefrom through a packing 106 in the end of cylinder 101. The free or outer end of stem is pivotally connected, as at 107, to a radial arm 108 which is xed to shaft 30 carrying the adjustable stop element or cam 29 (FIG. 1). I-f desired, radical arm 10S may have a suitable index projecting therefrom and cooperating with a numerical or other scale on the frame or base of unit 20 for indicating the setting or adjustment of cam 29.

Piston -104 dervides the interior of cylinder 101 into two chambers y109 and 110, respectively, `and a cushion loading air pressure is supplied to chamber 109 through a line 111 having a cushion loading regulator 112 interposed therein (FIG. 4). The other chamber 1-10 is automatically loaded through a positioner l113 to any pressure required to hold stem 105 in the position corresponding to the magnitude of the pneumatic signal transmitted by line 76.

As shown in FIG. 4, the positioner 113 may include a body '114 mounted on the head of cylinder 101 yand having a port 115 for connection to a line 116 through which a filtered supply of compressed air is supplied lto the positioner at a suitably regulated pressure. The body 114 further has a port =117 for connection to line 76 transmitting the pneumatic signal, and the port 117 communicates, by way of a passage 118, with a chamber 119 de'ned between llexitble diaphragms 120 and 121 having relatively large and small areas, respectively. Another chamber 123 is defined between a 'llexible diaphragm 124, preferably having the same area as the relatively small diaphragm 121, and the side of diaphragm 120 remote from chamber 119, and chamber 123 is in communication with the atmosphere by way of a vent 125.

The three diaphragms 120, `121 and 124 are all secured to =a plunger 126, and a range spring 127 is interposed between piston 104 and a carrier on plunger 126 to urge the latter in one direction, that is, toward the right as viewed in FIG. 4, while a suppression spring 128 is axially interposed between plunger 126 and an adjustable abutment 129 to urge the plunger 126 in the opposite direction. Chamber 11i? in cylinder 101 is in communication, by way of a passage 130, with a space 131 accommodating suppression spring `128, and space 1'31 is adapted to communicate with the atmosphere through a passage 132 in plunger 126 extending between chamber 123 and a valve seat at the end of plunger 126 in space 131. The space 131 is also adapted to communicate with the port 115 receiving the compressed air supply through a passage 133 terminating in a valve seat.

In order to control thecommunication of space 131 with either the atmosphere or the compressed air supply, the posi-tiener 113 further includes a ball valve member 134 engageable with the seat in passage `133 Iand having an elongated stem 135 Which-is engageable,.at its free 13 end, with the seat at the end of plunger 126 in 'space 131 to simultaneously close passage 132 of the plunger and to transmit the movement of plunger 126 to valve member 134 in the direction for unseating the latter.

It will be apparent that, when plunger 126 is moved toward the right, as viewed in FIG. 4, stern 135 closes passage 132 and is moved lby the plunger to unseat valve member 134 so that the compresesd a-ir supplied through the line v116 is then admitted to space 131 and passes from the latter through passage 1'30 to the chamber 1-10 in cylinder 101, thereby -to displace piston 104 toward the left against the cushion loading pressure in chamber 109. On the other hand, when plunger 126 is moved toward the left, as viewed in iFIG. 4, Iball 'valve member 134 is engaged against its seat in passage 133 lby the pressure of the supplied compressed air, and the plunger 126 moves away from the end of stem 135, thereby opening space 131 -to the atmosphere by way of passage y132, chamber 123 and 'vent 125.

In the positioner 113, the force exerted on plunger 126 as a result of the action of the pneumatic signal pressure in chamber 119 against the diaphragms 120 and 121 of unequal area, and the force of the range spring 127 are balanced by the oppositely directed force of the suppression spring 128, When these forces are in balance, a small pilot ow past valve member 134 ensures instautaneous response to any change in the pneumatic signal pressure fed -to chamber 119. An increase in the pneumatic signal temporarily moves the assembly of the diaphragms and plunger 126 toward the right, as viewed in FIG. 4, and thereby opens valve member 134 to permit an increase in the pressure within space 131 and charnber 110 of cylinder 101 so that, as previously described, piston 104 moves toward the left and thereby decreases the force of range spring 127. When the movement of piston 104 disposes stem 105 in the axial position corresponding to the pneumatic signal fed to chamber 119', the forces exerted by the pneumatic signal acting in chamber 119 and by the springs 127 and 128 are again in balance. Conversely, upon a decrease in the pneumatic signal fed to chamber 119, the disturbed balance of forces results in movement of plunger 126 toward the left, as viewed in FIG. 4, to open the exhaust from space 131 and thereby reduce the pressure in chamber 110 so that the cushion loading pressure in chamber 109 then moves piston 104 toward the right until the increased force exerted by range spring 127 and the force resulting from the reduced pneumatic signal acting in chamber 119 are again balanced by the force of suppression spring 128.

From the above, it is apparent that the position of stern 105 always corresponds to the magnitude of the pneumatic signal transmitted by Way of line 76, and that the pressure available for adjusting the position of stem 105 or for holding the latter in an adjusted position may be the full supply pressure in line 116 and is independent of the pneumatic signal.

The stop element or cam 29 is arranged to increase the amount of opening of gate S that is permitted when stem 105 is retracted or moved toward the right, as viewed in FIG. 4, in response to a reduced pneumatic signal. Conversely, cam 29 is adjusted to decrease the amount of opening of the gate that is permitted when stem 105 is extended or moved toward the left, as viewed in FIG. 4, in response to an increased pneumatic signal.

Although the above described pneumatically operated positioning device 100' is particularly suited for controlling the positioning of adjustable stop element or cam 29 of charge measuring unit 20, it is apparent that other devices may be used for adjusting the amount of opening of the gate that is permitted in accordance with the magnitude of the pneumatic signal transmitted by Way of line '76.

Thus, as shown in FIGS. 5 and 6 of the drawings, wherein all parts corresponding to those previously described with reference to FIGS. l to 4 are identied by 14 the same numerals, the pneumatically operated positioing device and the cam 29 actuated thereby are replaced by a simple single-acting, spring-loaded cylinder 100a having a piston 104a axially slidable therein and dividing the interior of the cylinder into compartments 109a and 110:1. A stem or plunger 29a extends axially from piston 104a and projects through one end wall of cylinder 100:1, and 4a helical compression spring 127:1 is disposed within compartment 109a and acts against piston 104a to urge the latter in the direction for retracting the plunger 29a. The pneumatic signal transmitted by line 76 is made to act in compartment 110:1 of Vcylinder 100a by suitably connecting line 76 to the cylinder so that, at any time, the position of plunger 29a is determined by the balancing of the opposed forces exerted on piston 104a by the spring 127a and by the pressure of the pneumatic signal in compartment 110'a, respec-` tively.y If the cylinder 100a has a relatively short lstroke and large diameter, the positioning of its plunger 29a in response to changes in the pneumatic signal fed by line 76 to compartment 110a will be suitably accurate, and the plunger 29a can then act directly as an adjustable stop element for the abutment 23a of lthe charge measuring unit 20. In order to make it possi-ble for the plunger 29a to act directly .as an adjustable stop element, the cylinder 10011 is iixedly mounted on Ithe frame or support 103a of unit 20 with the plunger 29a extending tangentially to the path of movement of abutment 23a and projecting into such path. Thus, when there is a decrease in the pneumatic signal .fed to cylinder 10011 by line 76, the co-nsequent retraction of plunger 29a acting `as .an

adjustable stop element for `abutment 23a permits fur-l ther 'opening of gate 5, whereas an increase in the pressure of the pneumatic signal causes extension of plunger 29a and decreases the permitted extent of opening of the gate.

Reference to FIG. 5 will show that an automatic loading control mechanism embodying the invention may include a handle 54a extending from lever arm 21 of the charge measuring unit 20 for effecting manual control over the loading operation, with such handle 54a replacing the relatively more complicated manual control arrangement provided vby the lever 54 which is connected through linkage 55 with shaft 53 of unit 40 in FIG. l.

It is also to be noted that the solenoid 50 of FIG. l maybe replaced by an air cylinder 50a (FIG. 5) having its plunger operating in the same way as the armature of the replaced solenoid, and with the supplying of air to cylinder 50a being under the control of a solenoid operated valve diagrammatically illustrated at 136 and having its energizing circuit controlled by switch 31.

Further, in the modification shown in FIG. 5, the link between lever arm 21 and lever |48 is divided into two parts 17a and 17b respectively connected -to Aa pressure fluid operated expansion cylinder 137 and to the plunger 138 of the latter. The cylinder 137 is of the single acting, spring-loaded type having two positions in which plunger l138 is fully extended and fully retracted, respectively. During loading of the basket, plunger 138 is fully extended, and the link 17u and 17b has an effective length equivalent to that of the link 17 in the irst described embodiment. At the conclusion of the loading operation, plunger 138 is retracted in order to rotate feeler 15 away from the annular basket charge 2 so that the feeler will not ride against the inner Iwall surface of the charge during centrifuging of the charge, thereby to extend the useful life of the feeler.

The above described arrangements embodying the invention for modifying the operation of the centrifugal loading control mechanism in accordance with a pressure sensed at point A in spout 4 operate as follows.:

When gate l5 is closed prior to the commencement of a loading cycle, pipe probe 60 senses the static pressure due to the hydrostatic head of charge material in supply tank 3, and. this sensed pressure causes a correspondingl l positioning of adjustable stop element 29 or 29a, by way of -valve device 70 and positioning device 100 or 1mm, to limit the initial opening of gate 5 to an extent which is slightly smaller than the optimum for even the most soupy, or at least viscous massecuite and that particular hydrostatic head.

When the loading cycle is initiated, gate S initially opens to the extent permitted by the above mentioned initial adjustment of stop element 29 or 29a and, as the charge material flows through spout l4, the combined static head and velocity head sensed by probe 6i) is less than the originally sensed static head, with the magnitude of this pressure drop depending primarily upon the viscosity of the charge material, as previously described. The reduced pressure sensed by probe 60 during ow of the charge material through spout 4 results in a correspondingly reduced pneumatic signal fed by line 76 to positioning device 100 or 10012 which readjusts stop element 29 or 29a in accordance with the changed pneumatic signal in' order to allow gate 5 to open further to the maximum opening which is the optimum for the actual viscosity of the charge material then flowing through the spout under that particular hydrostatic head. Changes in the viscosity of the massecuite or other charge material during the loading interval are sensed as pressure changes at the probe 60, as are changes in the hydrostatic head of charge material in supply tank 3, and the maximum gate opening is adjusted accordingly.

Thus, during successive loading cycles, the position of adjustable stop element 29 or 29a is varied as required to maintain optimum loading conditions, even though the hydrostatic head of charge material in tank 3 is progressively reduced and the viscosity of the charge material may vary over a Wide range.

It will be seen from the above that the automatic loading control mechanism embodying the invention substantially simulates the characteristics of a loading operation under the manual control of a proficient operator in that -the gate is opened initially to a relatively small extent to permit establishment of a flow of charge material, and the gate is thereafter opened further in accordance with the conditions of such flow.

Since the setting of adjustable stop member 29 or 29a at the beginning of each loading cycle, that is, when gate 5 is closed, is dependent only upon the hydrostatic head of charge material in tank 3, and since the pressure sensed by pipe probe -60 is reduced to modify the setting of the adjustable stop element in accordance with the viscosity of the charge material only in response to an actual flow of charge material through spout 4, it is apparent that a false indication or resetting of stop element 29 or 29a cannot result from the partial plugging of the gate by reason of the settling of the massecuite against the gate plate between loading cycles. If such partial plugging occurs, the pressure sensed by pipe probe 60 remains at the value dependent upon the hydrostatic head of charge material in the supply tank until the plug has had an opportunity to oo'ze out of the opened gate and thereby permit the establishment of the normal tlow dependent upon the actual viscosity of the charge material.

Although the iiow of water maintained through opening 62 of pipe probe 60 is primarily for the purpose of preventing clogging of the pipe probe by the charge material, it has been found that this purging ilow of water which is admitted to the spout through the pipe probe has the further advantage of lubricating the charge material if the latter becomes very viscous, and thereby tends to avoid plugging of the spout by the charge material when there is -a fairly long interval between successive loading operations.

Although the automatic control of the opening of gate 5 as described above maintains optimum loading conditions notwithstanding changes in the hydrostatic head of charge material in the supply tank or the viscosity of the charge material, it has been found that, when the gate opening is relatively small, for example, in response to the sensing of a pressure by pipe probe 6i) which corresponds to a full supply tank of charge material having a very low viscosity, the small gate opening actually tends to raise the trajectory of the stream of charge material issuing from the gate so that, even though the rate of ilow of change material is st-ill maintained uniform to avoid overloading of the basket, there is still the possibility that the raised trajectory of the stream of charge material will cause the latter to splash upon the curb of the centrifugal. In order to avoid this condition, a downwardly -inclined deflector bale 13S (FIG. l) may be secured to the lower edge of gate 5. The deilector bale 13S is effective to downwardly deflect the small streams of very Viluid charge material that would otherwise issue almost horizontally from the gate when loading the centrifugal from a full supply tank.

Although particular lembodiments of the invention have been described in detail herein with reference to the accompanying drawings, it is to be noted that the invention is not limited to those precise embodiments, and that various changes and modifications may be effected therein without departing from the scope or spirit of the invention, except as defined in the appended claims.

What is claimed is:

l. In a loading control mechanism for a cyclical centr-ifugal installation including a rotary basket, a tank for holding a ilowable charge material the iluidity of which is susceptible to variations, having a spout through which the charge material is to be discharged by pouring under gravity from the outlet end of the spout into the basket, a gate at the outlet end of thetspout, and gate operating means for opening and closing the gate; the combination of means responsive to the pressure head of the stream of said material ilowing in the spout when the gate is open for sensing the friction head loss in said stream, and means modifying the operation of said gate operating means in accordance with changes in the sensed friction head loss to vary lthe extent of opening of the gate in the direction for maintaining a controlled flow rate of charge material into the basket during successive loading cycles.

2. In a loading control mechanism for a cyclical centrifugal installation including a rotary basket, a tank for holding a ilowable charge material the fluidity of which is susceptible to variations, having a spout through which the charge material is to be discharged into the basket, a gate at the outlet of the spout, and gate operating means for automatically opening and closing the gate and having adjustable stop means for limiting the opening movement of the gate; the combination of pressure lluid operated positioning means for adjusting the stop means in accordance with a controlling pressure signal supplied thereto, means responsive to the pressure head of the stream of the charge material owing in the spout when the gate is open for sensing the friction head loss in said stream, and'means for supplying a pressure signal to said positioning means in accordance with said sensed friction head loss, thereby to cause said positioning means 'to adjust the stop means for limiting the opening movement of the gate to an extent tending to maintain a controlled iiow rate of charge material into the basket during successive loading cycles.

3. In a loading control mechanism for a cyclical centrifugal installation including a rotary basket, a tank for holding a iiowable charge material the uidity of which is susceptible to variations, having a spout through which the charge material is to be discharged into the basket, a gate at the outlet of the spout, and gate operating means for automatically opening and closing the gate and having adjustable stop means for limiting the opening movement of the gate; the combination of pressure uid operated positioning means for adjusting the stop means in accordance with a controlling pneumatic signal supplied thereto, responsive to the pressure head of the stream of the charge material allowing in the spout when the -gate is open for sensing the friction head loss in said stream, and means actuated by the sensed friction head loss and etective to establish a corresponding controlling pneumatic signal which is supplied to said positioning means for controlling the latter so that the stop means is adjusted by said positioning means for limiting the opening movement of the gate to an extent tending to maintain a controlled tlow rate of charge material into the basket during successive vloading cycles.

4. In a loading control mechanism for a cyclical .centrifugal installation including a rotary basket, a tank for holding a flowable charge material the tiuidity of which is susceptible to variations, having a spout -through which the charge material is to be discharged into the basket, a gate at the outlet of the spout, and gate operating means for -automatically opening and closing the gate and .having adjustable stop means for limiting the opening movement of the gate; the combination of pressure -tluid operated positioning means for adjusting the stop means in accordance with a controlling pressure signal supplied thereto, a pressure sensing probe disposed in the spout within the stream of charge material flowing through the spout when the gate is open for sensing the friction head loss in said stream, and means operated by the friction head loss sensed by the probe and establishing a corresponding pressure signal supplied to said positioning means for controlling the latter in a manner to cause said positioning means to adjust the stop means for limiting the opening -movement of the gate to an extent tending to maintain a controlled now rate of charge material into the basket.

5. In a loading control mechanism for a cyclical centrifugal installation including a rotary basket, a tank for holdin-g a owable charge material the fluidity of which is susceptible to variations, having a spout through which the charge material is to lbe discharged into the basket, a gate at the outlet of the spout, and gate operating means for automatically opening and closing the gate and having adjustable stop means for limiting the opening movement of the gate; the combination of pressure iluid operated positioning means for adjusting the stop means in accordance with a controlling pressure signal supplied thereto, a pressure sensing probe disposed in said spout within the stream of charge material flowing through the spout when the gate is open and facing at least partially against the direction of liow of said stream for sensing the friction head loss in said stream, and means operated by the friction head loss sensed by said probe and establishing a corresponding pressure signal supplied to said positioning means for controlling the latter in a manner to cause said positioning means to adjust the st op means -for limiting the opening movement of the gate to an extent tending to maintain a controlled ow rate of char-ge material into the basket.

6. In a loading control mechanism for a cyclical centrifugal installation including a rotary basket, a tank for holding a dlowable charge material the fluidity of which is susceptible to variations, having a spout through which the charge material is to be discharged into the basket, a gate at the outlet of the spout, and gate operating means for automatically opening and closing the gate and having adjustable stop means for limiting the opening movement of the gate; the combination of pressure uid operated positioning means for adjusting the stop means in accordance with a controlling pressure signal supplied thereto, a pipe probe having an opening in the spout within the stream of charge material owing through the spout when the gate is open for sensing the friction head loss in said stream, means supplying water to said pipe probe to tlow through said opening of the latter for preventing clogging of said opening by the charge material, and means connected to said water supplying means and sensitive to the sensed friction head loss transmitted through the water from said opening of the pipe probe to establish a corresponding pressure signal supplied to said positioning means for controlling the latter.

` 7` In a loading control mechanism for a cyclical centrifugal installation including a rotary basket, a tank for holding a owable charge material the iiuidity of which is susceptible to variations, having a spout through which the charge material is to be discharged into the basket, a gate at the outlet of the spout, and gate operating means for automatically opening and ,closing the gate and having adjustable stop means for limiting the opening movement of the gate; the com-bination of pressure uid operated positioning means for adjusting the stop means in accordance with a controlling pneumatic signal supplied thereto, means located in the spout responsive to the pressure head of a stream of the charge material flowing through the spout when the gate is open for sensing the friction head loss in said stream, a valve device for regulating the pneumatic signal supplied to said positioning means and including a movable valve member which determines the magnitude of said pneumatic signal in accordance with the position of said movable valve member, and actuating means for said valve member urging the latter in opposite directions in response to the friction head loss sensed in the spout and the pneumatic signal, respectively, so that said valve member is always disposed at a position where the effects of said sensed friction head loss and said pneumatic signal are balanced.

8. In a loading control mechanism for a cyclical centrifugal installation, the combination as in claim 7; wherein said means for sensing the friction head loss in the stream of charge material includes a pipe opening into the spout and a restriction for supplying water at a restricted rate of rlow through the said pipe to sense the head applied lby material at the pipe open-ing. and to prevent clogging of the opening by charge material, said pipe being connected to said actuating means'so that said valve device is actuated in accordance with the sensed friction head loss transmitted through the water in said pipe.

' 9. In a loading control mechanism for a cyclical centrifugal installation including a rotary basket, a tank for holding a tlowable charge material the fluidity of which is susceptible to variations, having a spout through which the charge material is to be discharged into the basket, a gate at the outlet of the spout, and gate operating means for opening and closing the gate; the combination of means responsive to the pressure head of a stream of charge material flowing through the spout when the gate is open for sensing the friction head loss in said stream, means establishing a pneumatic signal'corresponding to said friction head loss sensed in the spout, adjustable stop means for limiting the extent of the opening of the gate by said gate operating means, pressure lluid operated means connected to said stop means for adjusting the latter, and positioner means controlling the supply of pressure duid to said means for adjusting said stop means in accordance with said pneumatic signal in order to correlate the adjustment of the stop means with the magniture of the pneumatic signal.

10. In a loading control mechanism, the combination as in claim 9; wherein said means for adjusting said stop means includes a cylinder having a piston reciprocable therein and connected to said adjustable stop means, and said positioner means controls the supply of pressure fluid to said cylinder to positively dispose said piston at a location in the cylinder corresponding to the magnitude of the pneumatic signal received by said positioner means.

1l. In a control mechanism for a charging device including a tank for holding a flowable charge material, the uidity of which is susceptible to variations, having a spout through which the charge material is to be discharged by pouring under gravity from the outlet end of the spout, a gate at the outlet end of the spout and gate operating means for opening and closing the gate; the

combination of pressure sensing means disposed in the spout upstream of the gate for sensing the static head of the charge material in the spout when the gate is closed and for sensing the loss of head caused by the frictional resistance to the flow of material in the spout when the gate is opened, and means modifying the operation of said gate operating means in accordance with changes in the head sensed by said sensing means such that the gate is initially opened to an extent dependent upon the magnitude of the static head sensed with the gate in the closed position and, after flow of the charge material through the spout is established, the gate is further opened to an extent dependent upon the magnitude of the head loss sensed with the gate in its initially opened position.

l2. In a control mechanism for a charging device including a tank for holding a owable charge material, the fluidity of which is susceptible to variations, having a spout through which the charge material is to be discharged, a gate at the outlet of the spout and gate operating means for opening and closing the gate and having adjustable stop means for limiting the opening movement of the gate; the combination of pressure sensing means disposed in the spout for sensing the static head of the charge material in the spout when the gate is closed and for sensing the loss of head caused by the frictional resistance to the flow of material in the spout when the gate is opened, and means responsive to the said sensing means to vary the position of said adjustable stop means in accordance with the sensed heads so that the gate is initially opened to an extent dependent upon the magnitude of the static head sensed with the gate in the closed position and, after tiow of the charge material through the spout is established, the gate is further opened to an extent de pendent upon the magnitude of the head loss sensed with the gate in its initially opened position.

13. In a loading control mechanism for a cyclical centrifugal installation including a rotary basket, a tank for holding a mass of a charge material, that ows by gravity with a iiuidity susceptible to variations, said tank having a spout for delivering a stream of said charge material into the basket, a gate at the outlet of the spout and gate operating means for opening and closing the gate, the combination of a charge measuring device movable inward toward the center of the basket from a working position spaced from the inner wall of the basket by an increasing charge building up on said inner wall, control mechanism operable to eiect simultaneous out ward movement of the charge measuring device to said working position and actuation of said gate operating means for gate opening movement, an adjustable stop element coacting with a part of said mechanism to inactivate said gate operating means and limit the opening movement of the gate, means disposed in said spout for sensing the static head of said mass when the gate is closed and for sensing the loss of head in said spout caused by frictional resistance to the flow of said material through the spout when the gate is opened, and means responsive to pressure signals delivered by said sensing means to vary the position of the said adjustable stop element in accordance with changes of the head sensed by said sensing means in such manner that said stop element is given by the magnitude of said sensed head, irst, an initial position corresponding to an extent of initial gate opening movement desired for said static head and thereafter, when said gate is opened, an adjusted position corresponding to the full extent of gate opening movement desired for the condition of iiuidity indicated by said loss of head, said control mechanism including means responsive to inward movement of said charge measuring device from said working position to actuate said gate operating means progressively for gate closing movement, and finally to close said gate, independently of the position of said stop element,

14. In combination with a tank for holding a mass of a charge material that ows by gravity with a uidity susceptible to variations, said tank having a spout through which a stream of said material is to be discharged from the tank by pouring under gravity from the outlet end of the spout, and a gate at the outlet end of said spout for regulating the ilow of said material through the spout, a pipe containing a liquid and having a liquid-containing end portion disposed in said spout upstream of said gate in the path of the ow of said material in the spout when the gate is open, the liquid in said pipe being continually subject lto a pressure that varies in magnitude with variations of the head of the material in said spout contacting said end portion, and means responsive to resulting variations in the magnitude of the pressure 'of said liquid for generating control signals of corresponding magnitude.

l5. In combination with a tank for holding a mass of charge material that iiows by gravity with a fluidity susceptible to variations, said tank having a spout through which a stream of said material is to be discharged from the tank by pouring under gravity from the outlet end of the spout, and a gate at the outlet end of said spout for regulating the ow of said material through the spout, a pipe containing a liquid and having a liquid-containing end portion disposed in said spout upstream of said gate in the path of the flow of said material in the spout when the gate is open, the liquid in said pipe being continually subject to a pressure that varies in magnitude with variations of the head of the material in said spout contacting said end portion, and means responsive to resulting variations in the magnitude of the pressure of said liquid for generating control signals ofy corresponding magnitude, said end portion comprising an openfend of said pipe located inside said spout, and means for maintaining continuously through said pipe and through said open end into the material in said spout a restricted ow of said liquid under a predetermined feed pressure. v

i6. In combination with a tank for holding a mass of a charge material that ilows by gravity with a lluidity susceptible to variations, said tank havingfa spout through which a stream of said material is to be discharged from the tank by pouring under gravity fromthe outlet end of the spout, and a gate at the outlet end of said spout for regulating the ow of said material through the spout, a pipe containing a liquid and having a liquid-containing end portion disposed in said spout upstream vof said gate in the path of the iiow of said material in the spout when the gate is open, the liquid in said pipe being continually subject to a pressure that varies in magnitude with variations of the head of the material in said spout contacting said end portion, and means responsive to resulting variations in the magnitude of the pressure of said liquid for generating control signals of corresponding magnitude, said end por tion comprising an open end of said pipe located inside said spout, and means for maintaining continuously through said pipe and through said open end into the material in said spout a restricted ilow of said liquid under a predetermined feed pressure, said open end facing upstream in said path.

References Cited in the tile of this patent UNITED STATES PATENTS 750,542 Cole Ian. 26, 1904 1,551,702 Schaer Sept. l, 1925 2,207,921 Huxford .uly 16, 1940 2,727,630 Hertrich Dec. 20, 1955 2,837,241 Griswold lune 3, 1958 FOREIGN PATENTS ,580,519 France Y Sept. 3, 1924 .Patent No 3 39079 @O46 February 26U 1963 Ralph C,J Goodwin It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column lU line 55U for "change" read charge Column 3 line 19V for "laater" read me latter me; column 9U line l(1 for st-rips*N read M trips `mg column l2U line 19v before "at" insert as line 27U for t"radical"l read radial am; line 3lU for "devdes" read e@ divides ee; column 13X7 line 8 for 'eompresesd" read -m Compressed we; column 16@ line 7V for "ehangew read w charge me; line 75XY before Vrespolnsive" insert M means Signed and sealed this lst day of October 196.3e

(SEAL) Attest:

ERNEST W0 SWIDER DAVID L. LADD Atesting fficer Commissioner of Patents

Claims (1)

1. IN A LOADING CONTROL MECHANISM FOR A CYCLICAL CENTRIFUGAL INSTALLATION INCLUDING A ROTARY BASKET, A TANK FOR HOLDING A FLOWABLE CHARGE MATERIAL THE FLUIDITY OF WHICH IS SUSCEPTIBLE TO VARIATIONS, HAVING A SPOUT THROUGH WHICH THE CHARGE MATERIAL IS TO BE DISCHARGED BY POURING UNDER GRAVITY FROM THE OUTLET END OF THE SPOUT INTO THE BASKET, A GATE AT THE OUTLET END OF THE SPOUT, AND GATE OPERATING MEANS FOR OPENING AND CLOSING THE GATE; THE COMBINATION OF MEANS RESPONSIVE TO THE PRESSURE HEAD OF THE STREAM OF SAID MATERIAL FLOWING IN THE SPOUT WHEN THE GATE IS OPEN FOR SENSING THE FRICTION HEAD LOSS IN SAID STREAM, AND MEANS MODIFYING THE OPERATION OF SAID GATE OPERATING MEANS IN ACCORDANCE WITH CHANGES IN THE SENSED FRICTION HEAD LOSS TO VARY THE EXTENT OF OPENING OF THE GATE IN THE DIRECTION FOR MAINTAINING A CONTROLLED FLOW RATE OF CHARGE MATERIAL INTO THE BASKET DURING SUCCESSIVE LOADING CYCLES.

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