US2255681A - Fluid control system - Google Patents

Description

Sept 9, 1941 w. v. SAUTER ET AL r 2,255,681

FLUID CONTROL SYSTEM Original Filed May 18, 1935 BJP/W Patented Sept. 9, 1941 FLUID CONTROL 'SYSTEM William V. Sauter and Howard F. Lawrence,

Philadelphia, Pa., assignors to American Engineering Company, Philadelphia, Pa., a corporation of Pennsylvania Original application May 18, 11935, .Serial No.' 22,217, now Patent No. 2,173,884, ,dated September-26, 1939.

Divided and this application June 11, 1938, Serial No. 213,151

3 Claims.

This application is a division of our co-pending -application Ser. No. 22,217, filed May 18, 1935, and now Patent No. 2,173,884, granted Sept. 26, 1939, and the invention herein involved relates to iiuid control units adapted for assembly beneath the tuyre blocks of stoker furnaces.

It is the primary object of the present invention to provide a generally improved fluid control system for stoker furnaces which prevents an excess of air from flowing through the tuyres thereof upon a reduction in the fuel .bed resistance.

Another object is to provide a iluid control system for stoker furnaces which improves the distribution of air to the fuel bed whereby the latter is maintained normally uniform under all conditions of operation.

A further object is to provide an air control system for stoker furnaces consisting of one vor more brackets adapted to be .inserted beneath the tuyre blocks thereof, said brackets having mounted thereon a series of automatically operable dampers. p

A still further object is to provide a simplifled control device for regulating the flow of air through the tuyre blocks of a `Stoker furnace, which is highly efcient in operation, as well as economical in manufacture.

Other and further objects will become apparent as the description of the invention progresses.

Of the drawing, 1 lis a longitudinal sectional view taken through one of the retorts of a stoker furnace.

Fig. 2 is a side View partly in section, and diagrammatic in part, Vof a series of tuyre :blocks showing the uid control units comprising the present invention disposed therebeneath.

Fig. 3 is a plan view of .one of the fluid control units shown in Fig. 2.

Fig. 4 is an end view of the control unit shown in Fig. 3;- and Fig. 5 is a fragmentary side View partly in section of one of the automatically operable dampers provided in each of the fluid control units.

The present invention, for the purpose of illustration, is shown applied to a stoker of the underfeed type, although it is apparent that the invention is equally applicable to other types of stokers, as well as other apparatus wherein control of a fluid is desired. In the present instance the damper controlling the air flow to one tuyre overlaps with the damper controlling will close.

the air flow to an adjacent tuyre, and thus these overlapping dampers form communicating passages to the tuyres. In cases where the area of each of these communicating passages is substantially the same as the area of the -tuyre openings the pressure of the air therein is substantially the same as that flowing through the tuyres. Air is supplied to each of the tuyres from a common pressure or plenum chamber wherein the pressure remains substantially constant during operating periods of the furnace at any givenrating. It therefore will .be observed that should the fuel bed over any of the tuyres develop a blow hole, or become abnormally porous, so as to cause the velocity of .the air-supplied thereto to increase, while the fuel fed over an adjacent .tuyre block remains normal, thereby imposing the normal resistance to the air iiowing thereto, the damper .associated with the 4first tuyre will be subjected to a greater pressure at one side than at the other, and obviously will tend to move in the direction of the lesser pressure. As the velocity of the `air past a damper r.increases the` static pressure decreases, and as :a resul-t the damper will be urged to closed position Ato throttle the air supply -to the abnormally thin or porous portion of the fuel bed. Therefore, by this arrangement of overlapping dampyers .the flow of air through one tuyre is controlled, to a lcer-tain extent, by the flow of air through an adjacent tuyres.

. It therefore is seen that should thin or extrernely porous spots develop in the fuel bed the damper or dampers controlling the air thereto The Vfuel feeding elements will then have the opportunity to build u-p such thin .portions of the fuel bed before damage can occur to `the underlying grates. As the fuel bed builds up., Vand :therefore offers a greater resistance to .the flow of air through the associated tuyres, the differential kpressure acting upon the damper. or dampers controlling the air thereto will be reduced, and as `a result they will lmove toward open position .and again permit a normal quantity of .air to flow to those portions of the fuel bed, The dampers, therefore, tend to maintain the fuel bed normally uniform throughout and thus prevent blowing of the fuel, as well as damage to the grates, in the event abnormally thin spots occur therein.

Referring to the drawing, the numeral I designates a stoker of the underfeed type having alternately disposed retorts 2 and tuyre rows 3. Fuel is supplied to retorts 2 from a hopper 4, and .any suitable feeding device driven by a power mechanism indicated at feeds the fuel gravitating in hopper-4 to the retorts 2. A se- .ries of pushers 6 mounted in the bottom of Vwherein flow control is desired.

When the terms front and rear,are hereinafter used in connection with the description of the elements of the stoker I and the associated fluid control, it will be understood that the portions of such parts extending toward the rear or ash pocket 9 of the Stoker will be designated as rear and those portions thereof extending tow-ard the front or the driving mechanism 5 Yof the stoker will be designated as front. Referring'more particularly to Figs. 1 and 2, each tuyre row 3 comprises a series of superimposed tuyre blocks I0, each having a rounded nose or rear portion II, and a substantially rectangular front portion I2. 'Ihe upper surface I3 of each tuyre block is substantially flat and has a slightly beveled portion I4 extending around the nose portion thereof.

The tuyre blocks I8 are supported in the usual manner upon the side plates I5 of adjacent retorts 2, as shown in Figs. 1 and 2. The forwardly disposed ends I6 of the tuyre blocks I0 extend between adjacent side plates I5 and terminate in a transversely disposed beveled portion I1. Draft air enters the tuyre blocks from a common pressure or plenum chamber I8 disposed beneath the Stoker, which in turn supplied with air'from any suitable fan mechanism (not shown) in a well known manner.

- The mechanism for controlling the flow of fluid from plenum chamber I8 to the tuyre blocks `Ill comprises a series of independent units I9 disposed in end to end relation beneath the said tuyre blocks. Each unit I9 comprises a pair of substantially vertical side members 20 and 2|, which are jointed at their upper edges by a series of substantially flat cross members 22. A series of transverse brace members 23 also extend between side members 20 and 2|, to give greater rigidity to the structure. The flat cross members 22 are arranged in spaced relation in accordance with the spacing of the forwardly disposed ends I6 of the tuyreV blocks ID. As shown in Fig. 2, the cross members 22 abut the forwardly disposed beveled ends I1 of the tuyre blocks I0, and the spaces therebetween constitute the inlet openings for draft air. Each of the fluid control units I9 has pivotally mounted therein Y a series of damper units 24, one of said units being dis- I posed adjacent each ofsaid cross members 22.

Each'of the damper units'24 comprises a pair of damper elements 25 and 26 which extend between the side walls 20 and 2| of the associated unit, and which are connected for simultaneous movement by a link 21 of any suitable construction.

Each damper element 25 comprises a relatively flat portion 28 terminating at its rearwardly disposed end in an arcuate portion 29. The arcuate portion 29 makes an angle of substantially 90 degrees with the flat portion 28, and the rear surface of the former engages or is slightly spaced from the front edge of its associated cross member 22. The front end of each damper 25 is provided with a pair of depending apertured ears 30, the apertures Aof which in assembly align with apertures provided in the side members and 2| of the units I9. Pins 3| extending through these apertures pivotally support the damper elements 25. The damper elements are lsupported in open position by pins 32 extending inwardly from the side members 2U and 2| of each of the units. Damper elements 26 are also pivotally supported in any suitable manner, such as by pins 33 extending through apertures provided in the side members'28 and 2I of the units I9.

Referring more particularly to Fig. 2, it will be observed that the upper surface of each damper element 25 forms with the damper element 26 of the next higher unit, and with the side members 28 and 2| of a fluid control unit I9, an inlet passage 34 which communicates with the passage between a corresponding pair of tuyre blocks I8. By this construction all of the -air entering the tuyre blocks mustv pass through the inlet passages 34 before entering the fuel bed.

From the foregoing description it will be 0bserved that the lower surfaces of the damper elements 25, and the upper surfaces of elements 26 are subjected to the pressure in penum chamber I 8. However, since -the areas of these surfaces are substantially the same, it is apparent that no movement will be imparted to said elements by this pressure. It will also be observed that the upper surface of each damper element 25 is disposed in substantially overlapping arrangement with the lower surface of an element 26 of the next higher damper unit of the series. It is alsoseen' that since the damper elements 25 and 26 of each unit are interconnected by' a link element 21, any movement imparted to one of said elements Vis also imparted to they other. Therefore, should the velocity of the air in one inlet passage 34 increase, thereby reducing the static pressure operating against the upper surface of the associated damper element 25, while the velocity of the air in the next lower chamber 34 remains the same, thereby imposing 'the normalV pressure againstl the lower surface of the associated damper element 26, it willbe readily seen that since the pressure acting against the lower surface of element 26 is greater than'the pressure acting against the upper surface of the element 25, both of said elements of the unit will tend to move upwardly. These damper elements may be so designed that the dead weight thereof Will be sulcient to hold them open for a predetermined differential pressure, or they may have weights or springs associated therewith for that purpose. When this differential pressure increases due to a decrease in the fuel bed resistance, the associated damper element'25 will move upwardly into engagement with the damper element 26 of the next higher unit of theseries, to throttle the air flow to that portion of the fuel bed. When a damper element 25 hasthus been actuated to closed position a slight leakage of air occurs, and as a result the damper elements of the unit are subjected to differential pressure of suii'icient intensity to maintain them in closed position. If no leakage occurs under these conditions the damper element 25 would drop slightly fromy its fully closed position and would then be instantly actuated to closed position again. This action would be repeated until the fuel bed overlying the associated tuyre block imposes a greater resistance to the fiow of air and the weight of the damper elements 25 and 25 is sufcient to overcome the resulting change in differential pressure. In either case the air flow to the thin or porous portions of the fuel bed is throttled sufficiently to prevent the formation of blow holes, or damage to the tuyre blocks. Thus, when the air is so throttled the combustion rate will decrease, thereby enabling the fuel feeding elements to build up such abnormally thin or porous portions of the fuel fed until they again become normally uniform. This change in the fuel bed density creates a greater resistance to the flow of air through the associated passages 34 thereby decreasing the differential pressure acting on the associated damper elements, and as a result the damper elements will move downwardly to open position to permit more air to flow through the associated tuyre blocks.

Referring to Fig. 2, the damper elements shown at A, B and C, are in closed position, thereby shutting off the flow of air to the associated tuyre blocks. The arcuate portions 29 provided on each damper element 25 act as seals to prevent leakage of, air past the dampers when the latter are in closed position.

It therefore is apparent that the damper elements 25 and 26 associated with the tuyre blocks beneath the lighter or more porous portions of the fuel bed are operated automatically to close, or partially close the inlet openings thereto, while those associated with the tuyre blocks beneath the heavier portions of the fuel bed will remain open, and as a result proper distribution of air to all portions of the fuel bed is assured under all conditions of operation.

To assemble the fluid control units i9 in position beneath the tuyre blocks, it is only necessary to arrange them as shown in Fig. 2, and then secure them in place in any suitable manner, such as by bolts 35, which may pass through apertures provided in side plates l of adjacent retorts.

This construction, it is apparent, is equally adapted for use on new stoker installations as well as those already in service. The units I9 may readily be installed without modifying the Stoker in general. In this construction it will also be observed that the dampers are disposed substantially longitudinally in respect to the direction of air flow. Thus the impact head of the air flowing past the dampers has little or no effect upon the operation thereof.

While the embodiment herein shown is admirably adapted to fulfill the objects primarily stated, it is to be understood that it is not intended to limit the invention thereto since it may be embodied in other forms, all coming within the scope of the claims which follow:

What is claimed is:

1. In a device of the class described, an air control unit adapted for assembly beneath the tuyre blocks of a stoker, said unit comprising a framework consisting of a pair of side walls and a series of cross members extending between said side walls in slightly spaced relation defining a series of .relatively narrow passages, a series of damper units mounted adjacent said passages and forming with said side walls communicating passages to said first mentioned passages each of said damper units comprising a pair of interconnected damper elements, one of the elements of each of said pairs of damper elements forming one wall of its associated communicating passage and being subjected to the pressure of the air therein, while the other of said elements forms one wall of the communicating passage to an adjacent one of said first mentioned passages and is subjected to the pressure therein, whereby said damper units will be actuated to open or closed position, depending upon the intensity of the pressures acting at the opposite sides thereof.

2. In a device of the class described, an air control unit adapted for assembly beneath the tuyre blocks of a stoker, said unit comprising a framework consisting of a pair of side walls, and a series of cross members extending between said side walls in slightly spaced relation defining a series of relatively narrow passages, damper units disposed adjacent said passages and forming with the said side walls a series of communicating passages to said first mentioned passages, one side of each of said damper units forming one wall of its associated communicating passage and being subjected to the pressure of the air in said communicating passage, while the other side of each of said damper units forms one wall of an adjacent communicating passage and is subjected to the pressure of the air therein, whereby said damper units will be actuated to open or closed position, depending upon the intensity of the pressures acting at the said sides thereof.

3. In a device of the class described, an air 'control unit adapted for assembly beneath the tuyre blocks of a stoker, said unit comprising a framework consisting of a pair of side walls and a series of cross members extending between said side walls in slightly spaced relation defining a series of relatively narrow passages, a damper unit mounted adjacent each of said passages and extending in an upstream direction therefrom, said damper units forming with the said side walls communicating passages to said first mentioned passages, said damper units being disposed in substantially overlapping relation, one side of each of said damper units forming one wall of its associated communicating passage and being subjected to the pressure of the air therein, while the opposite side thereof forms a wall of an adjacent communicating passage and is subjected to the pressure of the air therein, whereby said dampers will move to open or closed position, depending upon the intensity of the pressures acting at the opposite sides thereof. Y

WILLIAM V. SAUTER. HOWARD F. LAWRENCE'.

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