US2002156A - Exhaust steam injector - Google Patents

Description

Filed Ma rch 7, 1934 3 Sheets-Sheet l INVENTOR EMANUEL PAM/501v. Wm/w ATTORNEY May 21, 1935.

E. RAWSON EXHAUST STEAM INJECTOR Filed March 7, 1934 5 Sheets-Sheet 5 ATTORNEY.

Patented May 21, 1935 fomrsos'rATEs r -Artur OFFICE,

EXHAUST STEAM INJECTOR Emanuel l tawson, North Bergen, N. J., assignor to The Superheate'r Company, New York, N. Y.

stApplication'March '7, 1934, Serial No. 714,384

y 9 Claims. (01. lot-2 The presentinvention relates to exhaust steam "injectors and has particular reference toexhaust steam injectors of the type adapted to be applied boiler feeding devices for locomotive boilers. Still more particularly the invention relates to exhaust steam injectors of the above-character 'aiidcontrol systems therefor adapted tobe ac tuated by the pressure of live steam admitted to the*locomotiveengine for automatically causing th e i'njector tobe operated wholly by live steam when exhaust steam from the locomotive engine is not available and for causing the injector to beoperated'by exhaust steam from the'locomo- 'tive engine when such steam is available.

Control systems actuated by the-pressure of live steamadmitted to a locomotive engine for causing such automatic change in operation of exhaust steam injectors are known broadly and have been utilized commercially with varying degrees of success. Practical experience with such injectors and control systems has demonstrated that certain undesirable characteristics of operation occur in practical service which wouldnot be expected from a theoretical consideration of the functioning of the apparatus, and it is one of the principal objects of the present invention to improve upon the construction of a live" steam actuated control or change-over system so as to eliminate the faults in operationwhich practical experience has shown to exist in previous systems of the character under discussion.

One of the principal functions of exhaust steam injectors, as applied to locomotives, is to conserve fuel by returning to the boiler as much as possible of theexhaust steam from the engine, which heat' is recovered by condensation of the exhaust steam in the injector. Experience has proved that under practical operating conditions, certain combinations of operating-facjtor's may arise which render operation of an injector by exhaust steam undesirable, if not impossible, and control systems heretofore developed have provided means whereby under the "control of the operator the injector may be positively shiftedto live steam operation in spite of the presence of'high pressure steam in the engine supply line which would normally 'act to shift the injector to exhaust steamopera'tion.

3 Experience has shown that with a control system provided with a so-called emergency position which insures operation of the injector as alive steam injector, regardless of the presence or absence of exhaust steam, the tendency of the operators of the injectors is, if the injectoris once 1 shifted to the'emergency position, to .iorgetto i2. mounted ,below the cab and is supplied witha through pipe IA.

returnthe control system to a normal operating position-and to allow it to continue to operate in the emergency. -It is evident that with the conoperator that the injector is not functioning in its normally intended manner to make use of exhaust steam when such steam is available.

Other andmore detailed objects of the invention and the manner in which the above general and detailed objects thereof are attained may best be understood by the ensuing description of suitable forms of apparatus for carrying the invention into eifect, taken inv conjunction with the accompanying drawings forming .a part of this'specification, in which Fig. 1 is a .mOre' or less. diagrammaticelevation of part of a locomotive showing injector ap- .25 paratus embodying the present invention;

. Fig. 2 is a more or less diagrammatic section on, alarger scale showing part of the injector and the valve apparatus illustrated in Fig. 1; i

Fig. 3 is a view similar to Fig. 2 showing a. diiferent form of apparatus; and

Fig. 4 is a view on a still larger scale'of .part of the apparatusshown' in Fig. 3.

In Fig. 1 the boiler of the locomotive is indicated generally at land the operators cab at .3

The injector indicated generally at A is water from the engine tender (not shown) .Overflow from the injector during priming periods passes through the over- 1 flow pipe i6 and water is delivered by the injector to thelboiler through the delivery pipe 18. Exhaust steam for operating the injector is conducted from a suitable place in the exhaust passage of theengine cylinder 2E! through the exhaust steam supply pipe .22, and live steam. for actuating. certain parts of the control system and for operating the injector is supplied from the boiler turret .24 through the pipe 26 .in which is located the main control valve B, the latter 5 being connected withthe injector by means of the steam supply pipes'28 and 30. Valve B is provided with. an manual control in the form. of

a hand wheel .32 located in the cab [2. Also located in cab |2,is the water control handle 5 the supply pipe I4. .to the injector is controlled by moving nozzle 34 for governing the amount of water supplied to the injector. Mounted adjacent to the main control valve B is the automatic or change-over valve C, the function of which will be explained later. This valve is connected with the injector body by means of pipe 36. The change-over valve C is connected by means of pipe 38 to a relay valve D which is in turn connected to the steam chest of the engine cylinder 20 or to the steam supply line leading to the steam chest by means of pipe 40. Live steam from the pipe 28 is supplied to the relay valve through pipe 42 and a vent pipe 44 connects the body of the relay valve with the body of the injector. Pipe 4'6 leads from the relay valve body to the interior of the cab I2 and is provided witha manually controlled valve 48. The discharge from valve 48 is open to the atmosphere at 50 and fluid discharged at 50, when valve 48 is open, is caught in a suitable pan or funnel 52 from which it is conducted through the drain pipe 54 to the .ash pan of the locomotive or other suitable place.

Relay .valve D is also vented to atmosphere or other suitable zone of low pressure by pipe 56.

Turning now to Fig. 2, in which the parts are shown in section, the injector illustrated is of known type and comprises a housing providing a main low pressure steam chamber 53 'to which exhaust steam is admitted from pipe 22 under the control of the exhaust valve 60. .Valve 60 is closed by spring 62 and is opened by live steam pressure acting on piston 04. Steam is admitted to piston 64 from pipe 36 leading from the change-over valve C.

Steam from chamber 58 flows to the main low pressure steam nozzle and water is admitted from the chamber 68 which is in communication with The amount of Water fed 66 longitudinally of the injector body by means of the control apparatus comprising the rotatably mounted spindle having an eccentrically mounted pin I2 engaging a suitable recess in nozzle 66. Spindle i0 is connected by means of 'so as to move longitudinally with the threaded control spindle '18 which carries the hand wheel A second valve head 80 is connected to the valve head it by means of a suitable lost motion connection 82. Valve head 16 controls flow of steam from pipe 26 to chamber 84, the latter being connected by means of pipe 28 and passage 88 in the injector to the high pressure steam nozzle 88. Nozzle 88 will hereinafter be referred to as the supplementary steam nozzle and the steam supplied therethrough will be referred to -92 forming a restriction or throttling orifice at the inlet of chamber 90.

The automatic or change-over valve C comprises a valve member 94 having a double faced valve head 96 seating alternatively against upper and lower valve seats formed in chamber 98, which chamber is in communication with chamber 90. Valve member 94 has a piston I00 loosely fitted in "the cylindrical chamber I02 and above this piston there islocated the check valve I04 seating to close com munication between chamber I02 and a chamber I06 with which pipe 38 communicates. Below chamber 98 there is provided the chamber I08, placed in communication with chamber 98 by means of passage H0. Chamber I08 is in communication with the inlet of pipe 30. Pipe 30 is in communication by way of the passage H2 and ports I I4 with the main steam chamber 58 of the injector;

The change-over valve member 94 is preferably provided with a suitable lower guide piston H0.

The apparatus which has been described above in detail constitutes one form of a live steam pressure actuated control system of a type which is known and Which in prior installations has been actuated by admitting steam directly from the engine steam chests to the chamber I06 through a pipe such as 38 shown in Fig. 2. In order to better understand the present invention, the operation of this portion of the apparatus, which constitutes prior art structure, and the nature of the faults in the operation thereof will now be explained.

Let it be assumed that the locomotive engine is running and exhaust steam for operation of the injector is available. Let it also be assumed that the main control valve B is open as shown in Fig. 2. With the valve head 76 open, supplementary steam at high pressure will be admitted to nozzle 88 and through a suitable known type of connection (not shown) a water valve controlling the flow of water to chamber 68 of the injector will be opened. The high pressure supplementary steam and the water will serve to prime the injector.

Valve head 80, being open, permits live steam to flow to chamber 98, and valve head 96 being in the lower position shown in Fig. 2, live steam flows to chamber I02 and through pipe 30 to the exhaust valve piston 64, thus opening the exhaust valve and permitting exhaust steam to flow to chamber 58 and the main low pressure steam nozzle 66. With the valve head 96 in its lower position, flow of live steam to chamber I08 and consequently through pipe 30 to the steam chamber 58 is prevented.

Under the conditions assumed, live steam from the engine steam chests is admitted through pipe 38 to chamber I66 and seats the check valve I04. Due to the fact that piston I00 is a loose fit in chamber I02, steam leaks past this piston to balance it and with this piston balanced the unbalanced pressure of steam in chamber 98, acting on the valve head 96, serves to maintain the change-over valve member 94 in its lower position.

With the parts in the position described the injector functions as an exhaust steam injector utilizing exhaust steam from the engine and a small amount of high pressure supplementary live steam, the latter being supplied at all times when the injector is in operation. If we now assume that the engine throttle is closed so that exhaust steam is no longer available, the action is as follows:

Steam pressure in pipe 38 fails and the steam in chamber I06 and in the space between the check valve and piston I00 is vented to the engine steam chests through pipe 38. Release of pressure above piston I00 causes this piston to become unbalanced and to lift the change-over valve member 94 so that valve head 06 seats against its upper seat toclose communication between chambers 98 a '0 an Open com n ca i n by r of i s ls passage H0, for flow of steam from chamber 98 to t e upply p p 8 an to th m in s em h h r .8 oi h 'i iec o At th a e t m i t the loose fit of piston I00, steamiromthe pipe 36 es a s t p p s m in t e exhaus va v (0 to clos n r th i uen i S n 62 When valve head 96 is on its lowersealt there is n flo f steam ii'o h m er 12 xc p ior the leakage flow past the clearance space around piston lljl lto the steam chests of the enginewhich always have a somewhat lower pressure than boilerpressnre when the engine is running) and con.- sequently the pressure in this chamber 15 substantially equal to boiler pressure, but when the changerover' valve shifts so as to open communication to the chamber ifiiif for flow of steam to the injector, the pressure of the steam admitted to chamber 98 is reduced bythe throttling action "of the restriction 92, so that the live steam admitted through pipe 33 to the. injector is ad.- mi t d the at a r su a xi a i av rage exhaust steam pressure. This live steam of reduced pressure will hereinafter be referred to as auxiliary steam.

vViihen the valve head 96 is seated. in its upper position, it will thus be evident that the lower faceof this valve is exposed to. the pressure of steam of only relatively low pressure. Consequently, when the engine throttle is again opened and high pressure steam from the steam chests is admitted to chamber Hit, the pressure exerted on the upper face of piston Hill is ample to cause shifting of the valve back to its lower position. Qheck valve I04 does not interfere with the admission of steam to piston i013 since when the valve member 94 is in its upper position, the check valve HM is mechanically lifted from its seat.

For purposes of considering operation of the system,'check valve Hi4. may be disregarded. This valve is provided only for the purpose of preventing leakage of live steam past piston H10 and into the. injector during periods when the engine is running and the injector is not in operation.

In order to have satisfactory practical operation of the injector, it is highly desirable that the control system effect chan eeover of operation of the injector from livesteam to exhaust steam and vice versa when the' most favorable conditions obtain for such change-over. highly desirable that the change-over be consistent. From a consideration of the mode of operation described above, it will be evident that the controlling factor in the change-over of,-operation is the difference in pressure between the two ides of the. vi n "3 of the h e over valve. By way of example, let us assume ,hat the injector isloperating on exhaust steam and; that itis desired to have the injector shift over to, live steam operation when the engine throttle is closed to an extent such that the pres.- e, of the-exhaust steam from the engine falls to a value of one pound or less above atmospheric. This condition of exhaust steam pressure will be represented by a corresponding relatively low s eam chest re u e a d on e l a a iv iv in r ss re in i e 8- e i b um d that thepressure pipe 38for this condition is 100 p unds e q ar n h-a d that h p es u of ive. steam from the boiler in chamber IQ? is 200 pounds per square inch. As the pressure in pipe 38-. drons om ts no m l P r o a valu s de ab be o t t chamb r 02 fl of h P essur e m mm c a ber It? to pe 38. comm n s nd h ressu n chamb -1 6' nd 1 .1-

Experience has shown that due to unavoidable wear and other practical operating factors the amount of steam flowing past piston I00 cannot be kept constant over long periods of operationand consequently for a given steam chest pressure at the outlet of pipe 38 there maybe variations of considerable magnitude in the pressure in chamber I06, 7 which variations obviously effect the change-over of the system from one type of operation to the other. Many attempts have been made heretofore to correct the difficulties encountered withthe type of valve under discussion due to the variations in its action, but long experience has shown that to change the construction in the diiferent ways'heretofore proposed leads to other difliculties in operation more disl advantageous than the diff culties sought to be remedied. Systems of the general character under discussion are comparatively very sensitive in operation and the relatively great number of factors which must be properly correlated renment under discussion is the fact that in locomotive installations, the injector is usually located adjacent the cab and consequently the pipe 38 leading to the steam chests is relativelylong, and also, because of practical considerations, is of relatively small diameter. It has been foundin' service that this pipe at times may become par.-

tially restricted due to foreign matter suchas' scale, rust or the like in the pipe, and frequently becomes partially restricted due to the pipe becoming dented. Since, in practical installations,

this pipe is frequently placed beneath the outer insulating cover of the boiler, it is extremely diflicult to reach and restrictions in it may not be known. Any restrictions in this pipe which are of sufhcient magnitude to materially alter the pressure drop between the ends of the pipe have the same effect of varying the steam chest pressure at which the injector changes over as does the wear in the valve whichorders the rate of flowpast the piston I00; The present invention eliminates the difficulties heretofore encountered with apparatus of the character describedand provides further advantages not obtainable with a para h f e used, a im e ma ine and in a way such that the invention is readily applicable to existing installations as well as being applicable to new equipment. i

The use of the invention in apparatus of a form applicable for installation with existing apparatus is shown in the embodiment illustrated in Fig.2. In this embodiment there isinterposed between the pipe 41) leading from the engine steam ch st and h ipe 38. c n ct d to the chamber H16 of the change-over valve, the relay valve mechanism indicated generally at D. This mechanism comprises a relay valve member [L8 having a double faced head [2 0 located in chamber I22 with which pipe 38 communicates. When the valve head I2!) is seated against the lower valve seat cooperating therewith, communication is closed between pipe 38 and the vent 55 and commumcation is established between pipe, 38 and chamber I24 which is, connected by means of pipe 42 with the high pressure steam supply pipe 28, The relay Valve member [L8 is provided at its upper end with a piston I26 slidably mounted in the valvehousingand having a small leak passage I28 passing therethrough. Passage I28 provides constant communication between chamber I24 and a chamber I30 located above piston I26. Restricted communication between chambers I24 and I39 may be provided by other means such, for

'instance, as a small passage in the valve housing ,or a clearance space betweenpiston I26 and the housing. chamber I32 by means of a vent port I34 and Chamber I30 is connected with chamber I32 is vented by means of pipe 45, preferably to the low pressure steam chamber of the injector. Vent port I34 is controlled by the vent valve I36 which is in the form of a plunger, the upper end of which is located in chamber I38.

Pipe 40 connects chamber I38 with the engines Vent valve I36 is As previously explained, the operation of the injector on exhaust steam or auxiliary live steam is determined by the presence or absence of :steam of predetermined pressure in chamber I86 of the change-over valve, and the relay valve arrangement just described operates to control the pressure in this chamber in the following man- 30 j Let it be assumed that the injector is in opcration and that the engine of the locomotive is running." Whenever the main control valve B is open, that is, whenever the injector is operating,

high pressure live steam is supplied through pipe 42 to chamber I24 and, if the valve head i 28 is in the lower position shown in the figure, this high pressure live steam flows through chamber H22 and pipe 38 to thechamber i86 causing the change-over valve to assume the proper position -'for' exhaust steam operation. The position taken 'by the relay valve member H3 is determined by 'the presence or absence of pressure inchamber 'I3Ilabove piston I26. If pressure isbuilt up in chamber I39 soas to balance the piston I25, the valve will assume the position shown in the figure and, if the pressure in chamber I33 is released, the pressure of steam in chamber I24, acting on the lower face of the piston, will lift the valve member I I8 so as to seat the head 52!; in its upper position. In this position of the valve head, the supply of high pressure steam from pipe 42 to chamber IE6 is cut off and chamber we is simultaneously vented to atmosphere through the vent connection 55. When pressure is released from chamber Itilfthe change-over valve, as previously described, shiftsto changeopera tion of the injector to live steam operation;

Due to the presence of the leak passage I 28 through piston I25, chamber I3!) is in communication with a source of high pressure live steam at all times when the injector is in operation and the presence or absence of a pressure in chamber ISBis determined by the position of the vent valve I36 (assuming the valve 48 in the cab for controlling the pipe M5 to be closed). As will be evident upon the drawings, the vent valve I will be closed when pressure in chamber I38 oi steamadmitted thereto from the steam chest or supply pipe through pipe is sufiicient to overcome the spring Mi] and the pressure exerted on the lower face of the valve when the, valve is closed.

The above described relay valve arrangement operates to eliminate the difliculties heretofore encountered and the possibility of change over of the injector at varying steam chest pressures, for

the following reasons:

Piston I00 of the change-over valve is actuated by a supply of high pressure steam flowing substantially directly from the boiler and of relatively constant pressure.- While the boiler pressure may vary, it nevertheless is practically at all times at relatively high pressure, and even under conditions when the boiler pressure is abnormally low so that the pressure in chamber 506 is considerably below normal, the condition of low boiler pressure also reduces the pressure of the steam acting on the valvemember 94 in opposition to the pressure in chamber H36 so that variations in boiler pressure may for practical purposes be neglected. The previously employed long pipe connection from the change-over valve to the steam chests is'eliminated and in place of this long connection there is substituted the short and relatively'free connection for venting the chamber I86 which comprises the pipe 38 connecting the change-over and relay valve housings and-the direct atmospheric vent from chamber I22 by way of pipe 56, which pipe may be very short and which, if desired, may be omitted (entirely, since the' amount of steam escaping vtheretlu'oughbeforethe automatic valve shifts to seat in its upper'position is very small. Thus,

'with the present arrangement, chamber Hi6 may be said to be freely vented to atmosphere and any increase in the amount of steam passing piston I80, due to wear in this piston, does not affect the pressure in chamber H36 because of the free venting of this chamber to the atmosphere. In practical operation the action of the apparatus is such that the change-over valve shifts substantially simultaneously in response to shift of position in the relay valve head I20, re-

gardless of variations in clearance in the changeover valve mechanism due to wear or other causes. Due to the fact that steam from chamber I30 of the relay valve. is vented through pipe 44 and does not have topass through the long pipe 49 leading to the engine cylinders, the amount of steamilow through pipe '45) necessaryto close the vent valve E36 or to relieve the pressure in the small chamber I38 so as to permit this vent valve to open, is so small that restrictions in pipe 48 which may occur in service have little, if any, effect upon the steam chest pressure required to effect opening or closing of the vent valve with any given adjustment of spring I46). Thus, instead of an apparatus which in service may cause change over of operation of the injector at different steam chest pressures, which is highly undesirable, there is provided in accordance with the present invention an apparatus which will consistently eifect change overof the injector at the steam chest pressure for which the apparatus is set. Furthermore, the apparatus provided by the present invention permits, through the adjustment of the tension on spring me, 'an accurate control of the steam chest pressure at which the apparatus will function to effect change over .advantageous pressure for any given locomotive to which the injector apparatus may be applied. Thisfeature of readyadjustability is not possible of attainment with prior systems.

Considering now.the matter of the provision ofan emergency position. whereby the injector may be caused to operate as a live steam injector at the will of the operator, regardless of the presonce or absence of exhaust steam,'it will be evidentuthat if the valve 48 in the cab is openedby the operator, chamber I of the relay valve will be vented to atmosphere through pipe 46 regardlessof whether or not the vent valve I36 is opened or closed. If valve 48 is open, the action of the relay valve will be the same asif the vent valve I36 had been opened by failure of pressure in pipe40; the change-over valve will consequently be shifted to auxiliary live steam operating position, and the change-over valve will remain in this-position so long as valve 48 is open. However, when valve 48 is open, steam from chamber I24. leaking constantly through the passage I28 to chamber I30 and normally passing through pipe44 when valve I36 is open, flows to atmosphere'in the cab at 50. This constant supply of steam, although relatively small in quantity, provides a constant and annoying reminder to the operator that the injector is in emergency position and, as a result, the operator can be depended upon, as soon as the conditions requiring emer-[ gency operation have ceased to exist, to close valve 48 and thus restore the control system to normal operation in which exhaust steam will be utilized when it is available.

Turning now to Figs. 3 and 4, another form of apparatus embodying the invention is shown, in which the separate change-over valve and relay valve structures of Fig. 2 are dispensed with and a combined change-over and relay valve arrangement is substituted.

In Fig. 3 the form and arrangement of the injector A and the main control valve B are the same as that previously described, except that in the control valve the choke or throttling member 92 is dispensed with.

In the present arrangement chamber 90 of the main control valve is in communication with a chamber I50 which is connected with chambers I52 and I54 by passages I56 and I58, respectively. A double headed change-over valve I60 is arranged with a lower piston-like head I62 located in chamber I52 and an upper, double facedhead I64 located in chamber I54. Chamber I52 communicates with the auxiliary steam supply pipe 30 in which is located an adjustable restricting valve I66 for reducing the pressure of auxiliary steam flowing to the injector. Chamber I54 communicates with chamber I 68 by way of passage I 10 and is also placed in communication with the exhaust .valve operating piston 64 by pipe 36. Chamber I68 is vented to atmosphere'or other zone of low pressure by pipe 56. Below the piston head I62 is chamber I12 which communicates by way of the vent port I14 with chamber I16. Pipe 46 leading to the emergency control valve 48 in the cab also communicates with chamber I12. Pipe 44 vents chamber I16, preferably to the low pressure steam chamber of the injector.

Vent port I14 is controlled by the vent valve I18 carried by diaphragm I and urged toward open position by spring I82, the tension of which is preferably made adjustable as indicated. Below the diaphragm I80 the casing structure provides a chamber I84 in communication with chamber I86 by way of ports I88. Chamber I86 is connected by pipe 40 to the steam supply line of the engine. The details of construction of the form of. valve head I62 are shown on an enlarged scale in Fig. 4. .As shown in this figure, the lower valve head I62 is loosely mounted on the stem of the valve member I60 between collars I90 and I92 so communication between chambers I52 and I12,

which restricted communication, may be pro.-

vided by other specific forms of passages. The operation of this form of apparatus is as follows:

The presence or absence of steam from the supply line to the engine in chamber I84determines the position of the vent valve I18 and consequently determines the presence or absence of pressure in chamber I12, to which chamber-a restricted quantity-of steam can flow by way of the clearance spacev I64 and recess I96. The presence or absence of pressure in chamber I12 determines the position of the change-over valve When the engine is not operating and chamber I12 is vented through port I14,-the pressure of steam in. chamber I50 acting on the upper face of head I 62 over-balances the pressure acting in the opposite direction on the smaller upper head I64 and the valve assumes the position, shown in the drawings so as topadmit auxiliary steam to the injector. In this. posi-' tion of the change-over valve,.head I64 seats to close passage I58. thus cutting off the supply of actuating steam supplied to the exhaust valve from chamber I54 by way of pipe 36. At the same time chamber I54 is vented to, atmosphere by way of passage I10 and pipe 56, thus releasing all pressure from pipe 36 so that the exhaust valve can close. With the changeover valve member in this position, high pressure live steam can, as previously pointed out, leak past the head I62 to the chamber I12 so that when the admission of steam to the engine supply line causes the vent valve I18 to be closed, pressure will build up in chamber I12 to over-balance the change-over valve and cause it to move to its upper position.

In its upper position the-upper valve head is shifted to close passage I10 and to open passage I58 so as to admit actuating steam to the exhaust valve piston 64 and cause the exhaust valve to be opened. At the same time the seating of the lower head I62 closes passage I56 connecting chambers I50 and I52 to shut ofl the supply of auxiliary live steam to the injector. In the upper position of the change-over valve member it will be evident that both'the upper face of the upper head I64 and the upper face of the lower head I62 must seat and in order to insure proper seat-. ing of both of. these heads, theyare preferably. not rigidly connected to each other.

It will be evident that the arrangement just described provides the same'advantages over ex-. isting systems as the arrangement shown in Fig.

2. The construction does not involve the flow 7 since allof the pressures affecting the positioning of the valve are derived from the same sourcepf steam supply. As in the formshown Fig-.12;

the convenient emergency feature is readily jobtained by placing the chamber I12 in communication with the pipe 46 leading to the engine cab. Also, ready adjustability ofthe steam chest pressure at which the apparatus will effect changein operation of the injector is provided by the simpleadjustment of the tension of spring I82 acting on the vent valve H8.

From the foregoing description it will be evident that the present invention may be embodied in widely diiierent forms of apparatus and it is therefore to be understood that the invention is in no way limited'to the forms of construction shown herein by way of example nor is it to be considered as being limited in its application to the specific forms of injector and control system shown herein.- For-example, it is evident that the invention is equally applicable to exhaust steam injectors of the multiple-stage type wherein instead of utilizing supplementary high pressure steam in the same stage of the injector as the low pressure steam, the high pressure steam is employed in a separate'high pressure or boosting stage. Also, in installations where the injector is intended to deliver only against relativelylow pressure and auxiliary live steam alone is sufiicient without the aid of supplementary live steam in any form, the present invention is equally applicable.

It is further to be understood that certain features of the invention can be employed to the exclusion of others and the invention is to be consideredas embracing all such forms of. construction 'as fall within the scope of the appended claims when construed as broadly as is consistent with the state of the prior art.

What I claim is:

1. In a feed water system including an exhaust steam injector for supplying water to a steam generator which supplies steam to a steam consumer,said injector being of the type adapted to be operated by auxiliary live steam when exhaust steam from said' consumer is not available, a control system for changing from exhaust steam to auxiliary live steam operation including a valve for controlling admission of auxiliary live steam to theinjector, a connection providing a path for flow of pressure fluid from a source of relatively high pressure to a zone of relatively low pressure, means responsive to variations of pressure in said connection for controlling the position of said valve, valve means for controlling flow through'said connection for varying the pressure 1 therein, and means responsive to variations in the pressure of steam supplied to said consumer for operating said valve means.

2. In a feed water system'including an exhaust steaminje'ctor for supplying water to a steam l generator which supplies steam to a steam consumer, said injector being of the type adapted to be operated by auxiliary live steam when exhaust steam from said consumer is not available, in combination therewith, a control system for changing from exhaust to live steam operation including a valve for controlling admission of auxiliary live steam to the injector, a connection providing a path of flow of steam from said generator to a zone of lower pressure, means responsive tovariations of pressure in said connection for controlling the position of said valve, valve means for controlling flow through saidconnecltion'for varying the presure therein, and means responsive to variations in the pressure of a steam supplied to' said consumer for operating to be operated'by auxiliary'live steam whenexhaust steam from said consumer is not available,"

a control system for changing from exhaust steam to live steam operation including a valve for controlling admission of auxiliary live steam:

to the injector, a connection providing a path. of flow of steam from said generator to a zone of lower pressure, means responsive to decrease of pressure in said connection for opening said valve, valve means for controlling flow through said connection for varying the pressure therein,

and means responsive to a decrease toja pre-,

determined value in the pressure of steamsupplied to said consumer for opening said valve means.

4. In a control system for an injector adapted.

to be operated by exhaust steam from a steam consumer and adapted to be operated byauxiliary live steam when exhaust steam from said consumer is not available, a valve for control ling admission of live steam to the injector,

means providing a pressure chamber, means for,

supplying high pressure steam to said chamber, means responsive to pressure variations in said chamber for controllin the position of said iary live steam when exhaust steam from said consumer is not available, a valve for controlling admission of auxiliary live steam to the injector, means providing a pressure chamber, means for supplying high pressure steam to said chamber, means responsive to pressure drop in said cham" her for opening said valve, means providing a path of flow for freely venting said chamber to a zone of lower pressure, valve means in said path for controlling flow therethrough, and means responsive to a decrease to a predetermined value in the pressure of the steam supplied to said consumer for opening said valve means.

6. In a control system for an injector adapted to be operated by exhaust steam from a steam consumer and adapted to be operated by auxiliary live steam when exhaust steam is not available, a valve for controlling admission of auxiliary live steam to the injector, means providing a pressure chamber, means for supplying high pressure steam to'said chamber, means responsive to pressure variations in said chamber for controlling the position of said valve, means providing a path of flow for freely venting said chamber to a zone of lower pressure-valve means in said path for controlling flow therethrough, means providing a second chamber, means responsive to variations in pressure within said second chamber for operating said valve means, and a conduit adapted to contain steam in static condition for communicating to said second chamber pressure variations of the steam supplied to said consumer. I

'7. In a control system for an injector adapted to be operated by exhaust steam from a steam consumer and adapted to be operated by auxiliary live steam when exhaust steam is not available, a valve for controlling admission of auxiliary live steam to the injector, means ,pro-. viding a pressure chamber, means for supplyvalve, means providing a path of flow for freely,

inghigh pressure steam to said chamber, means responsive to pressure drop in said chamber for opening said valve, means providing a path of flow for freely venting said chamber to a zone of lower pressure, valve means in said path for controllingffiow therethrough, means providing a second chamber, means responsive to a decrease to a predeterminedvalue of the pressure Within 'saidsecond chamberflfor opening said valve means, and a conduit adapted to contain steam in static condition for communicating to said second chamber pressure variations of the steam supplied to said consumer.

8-. In a control system for an injector adapted to be operated by exhaust steam from a steam consumer and adapted to be operated by auxiliary'live steam when exhaust steam from said consumer is not available, a valve for controlling admission of live steam tothe injector, means providing a pressurechamber, means for supplying high pressure steam to said chamber, means responsive to pressure variations in said chamber for controlling the position of said valve, means providing a path of flow for freely venting said chamber to a zone of lower pressure, valve means-in said path for controlling flow therethrough, means providing a second cham-- ber, means responsive to variations in pressure within said second chamber for operating said valve means, a conduit adapted to contain steam in static condition forcommu'nicating to said second chamber pressure variations of the steam supplied to said, consumer, and means for operating said valve means independently of the pressure in said second chamber. 7 9. In acontrol system for an injector adapted to'be operated byexhaust steam from a steam consumer and adapted to be operated by auxiliary live steam when exhaust steam from said consumer is not available, a valve for controlling admi'ssion of auxiliary live steamto the injector, means providing apressure chamber, means'for supplying high pressure steam to said chamber, means responsive to pressure drop in said chamber for opening said valve, means providing a path of flow for freely venting said chamber to a zone or" lower pressure, valve means in said path for controlling flow therethrough, means providing a second chamben'means responsive to a decrease to a predetermined value in the pressure within said second chamber for opening said valve means, a conduit adapted to contain steam in static condition for communicating to said second chamber pressure variations of the steam supplied to said consumer, and means for opening said valve means independently of the pressure in said second chamber. 7

10. In a steam locomotive having an operators cab, a control system for an injector adapted to be operated by exhaust steam from the locomotive engine and adapted to be operated by auxiliary live steam when exhaust steam from the engine is not available comprising a valve for controlling admission of auxiliarylive steam to the injector, means providing a pressure chamber, means for supplying high pressure steam to said chamber, means responsive to pressure variations in said chamber for controlling the position of said va1ve, means providing a path for flow of steam from said chamber to a zone of lower pressure, valve means in said path for controlling flow therethrough, means providing a balance chamber, means for supplying high pressure steam to said balance chamber, means responsive to pressure variations in said balance chamber for operating said valve means, means for venting said balance chamber toa 'zohe cf lower pressure, a valve for controlling flow through the vent, means responsiveto variations in the pressure of the steam supplied to said engine for operat'mg the last-mentioned valve, and independent means for venting said balance chamber to'azone of lower pressure comprising a conduit having an open discharge within said cab and a manually operable valve in said conduit, i

i 11. In a control system for an injector "adapted to be operated by exhaust steam from a steam consumerand adapted to be operated by auxiliary live steam when exhaust steam from said consumer is not available, a valve for controlling admission of auxiliary live steam to theinjector, means providing apressure chamber, means for supplying high pressure steam to said chamber. means responsive to pressure variations in said chamber for controlling the position of said valve, means providing a path for flow of steam frorn said chamber to a zone of lower pressure, valve means in said path for controlling flow therethrough, means providing a balance chamber, means for supplying high pressure steam to said balance chamber, means responsive to pressure variations in said balance chamber for operating said valvemeans, means forventing said balance controlling flow through the vent, means responsive to variations in'the pressure of the steam supplied to said consumer for operating the lastmentioned valve, and independent means for venting said balance chamber to a zone of lower pressure comprising a conduit and a manually operable valve in said conduit.

12. In a control system for an injector adapted to be operated by exhaust steam from an engine and adapted to be operated by auxiliary live steam when exhaust steam from the engine is not available, a first valve for controlling admission of exhaust steam to the injector, pressure respone sive means for operating said valve, a second valve for alternatively supplying auxiliary live steam to saidinjector and to said pressure responsive means, means providing a balance chamber, a piston reciprocably mounted in said chamber and'operatively connected to said second valve, means for supplying live steam to both sides of said piston, means providing a path of flow for freely venting said balance chamber to a zone of lower pressure, valve means for controlling flow through said path, and means responsive to variations in the pressure of the steam supplied to said engine for operating said valve means.

13. In exhaust steam injector apparatus, an automatic control system for shifting the injector to live steam operation when exhaust steam is not available including a pressure chamber, means placing said chamber in constant but restricted communication with a source of high pressure steam and means for setting the control system in exhaust steam operating position in response to pressure in said chamber, a vent conduit in communication with said chamber, and a manually controllable valve in said conduit for venting said chamber at will to prevent exhaust steam operation regardless of the presence or absence of exhaust steam.

14. In a locomotive having anoperatorscab,exhaust steam injector apparatus including a steam pressure actuated control system for automati cally shifting operation of the injector to live steam operation when exhaust steam is not available and vice versa, said system having a pressure chamber to a zone of lower pressure, a valve for chamber, means for shifting the system to exhaust steam operating position in response to pressure of-steam'in said chamber and a conduit for continuously supplying high pressure steam to said chamber when steam is supplied to the engine of the locomotive, a vent conduit communicating with said chamber and having its discharge end located in said cab, and a valve operable from the cab by the operator for controlling flow through said conduit. v

15. In a locomotive having an operators cab, exhaust steam injector apparatus including a steam pressure actuated control system for automatically shifting the injector from exhaust steam operation to live steam operation when exhaust steam is not available and vice versa, said system comprising a vent conduit adapted to be opened to prevent shifting of the system to exhaust-steam operating position,.said conduit being-in communication with a source of steam when the system .is in live steam-operatingposition and having its discharge end located in said cab, and a valve operable from the cab by the operator for controlling flow through said conduit. '16. In a steam pressure actuated control sys-v tem for exhaust steam injectors, means providing a pressure chamber,- means for supplyingactu-. ating steam to said chamber, an element responsive to pressure in saidv chamber for shifting the system to exhaust steam operating position, a first conduit for venting said chamber. to shift the system from exhaust steam operating position, a valve for automatically closing said conduit une der predetermined operating, conditions, a second conduit for venting said chamber, and a manually operable valve in said second conduit-adapted tobe opened to render the automatic closing of the first-mentioned valve inefiective to shift the system to exhauststeam operating position.

17. In. exhaust steam injector apparatus, 1 a steam pressure actuated control system for an.- tomatically shifting the injector .from exhaust steam operation to live steam operation when exhaust steam is not available and vice versa in-, cluding a pressure chamber in continuous communication with a source of high pressure steam when steam is supplied to the engine from which exhaust steam is derived for injector operation, a vent conduit in continuous communication with said chamber and said source for venting said chamber to prevent shift of the injector to ex-, haust steam operation, and a manually operable valve in said vent conduit.

18. In a locomotive, exhaust steam injector api paratus including a steam pressure actuated control system for automatically shifting the injector from exhaust steam operation to live steam operation when exhaust steam is not available and vice versa, said system including a pressure chamber and means responsive to pressure in said chamber for shifting the injector to exhaust steam operation, conduit means placing said chamber in continuous communication with a source of high pressure steam when steam is admitted to the engine of the locomotive, whereby the injector is normally shifted to exhaust steam operation when steam is admitted to the engine, a vent conduit for continuously venting said chamber of the steam admitted thereto from said source, and a manually operable valve for opening said vent conduit.

19. In a locomotive having an operator's cab, exhaust steam injector apparatus including a steam pressure actuated control system for automatically shifting the injector from exhaust steam operation to live steam operation when exhaust steam is not available and vice versa, said system including a pressure chamber and means responsive to pressure in said chamber for shiftingthe injector to exhaust steam operation, conduit means for placing said chamber in continuous communication with a source of high pres sure steam when steam is admitted to the engine, whereby the injector is normally shifted to exhaust steam operation when steam is admitted to the engine, a vent conduit in continuous com munication with said chamber and having an outlet located in said cab and a valve manually operable 'from said cab for opening said conduit whereby to vent said chamber to cause the injector to be operated as a live steam injector regardless of the presence or absence of exhaust steam and to continuously conduct to the cab high pressure steam from said source when exhaust steam is available and the injector is operated as a live steam injector due to the opening of said vent conduit.

' EMANUEL RAWSON.

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