US2389656A - Injector - Google Patents

Description

Nov. 27, 1%45. A, w s AL 2,389,656

INJECTOR Filed Feb. 27, 1942 BOILER Patented Nov. 27, 1945 2,389,656 INJECTOR Arthur Williams, Munster, Ind.,

and Erich Henkel, Calumet City, 111., assignors to The Super-heater Company, New York, N. Y.

Application February 27, 1942, Serial No. 432,620

18 Claims.

The present invention relates to exhaust steam injectors and has particular reference to exhaust steam injectors of the kind adapted to feed water to locomotive boilers and to be operated wholly by live steam, so that the boiler of the locomotive may be fed when exhaust steam from the engine is not available.

The primary reason for using exhaust steam injectors of the above described general type, rather than ordinary live steam injectors, is to improve the economy of operation of a locomotive by condensing a portion of the steam exhausted from the engine in the injector and returning the heat of the condensed exhaust steam to the boiler in the feed water supplied thereto by the injector which effects such condensation.

A primary object of the present invention is to increase the economy possible to obtain by the use of an exhaust steam injector, by the provision of a new and improved form of injector apparatus by means of which the quantity of exhaust steam that can be condensed in the injector and returned to the boiler under given conditions can be increased as compared with previous forms of injectors.

Exhaust steam injectors, when employed as boiler feeding devices must operate under widely varying conditions which tend to materially affect operating range and capacities. Thus, at different times the injector may be called upon to operate under widely varying boiler pressures which not only affect the pressure against which the injector must deliver, but also affect the pressure of the steam available to operate the injector. Also, the temperature of the feed water delivered to the injector may vary within wide limits, the variations in this temperature obviously affecting the condensing capacity of the device. Further, the conditions prevailing when the injector is operated wholly on live steam are not identical with those prevailing when the injector is being operated on exhaust steam.

The present invention accordingly contemplates the provision of improved injector apparatus whereby the above noted and other variable conditions under which the injector must operate are taken into account and compensated for in a manner which improves the operating range and capacity of the injector, as compared with previous injectors under all of the conditions of. injector operation which may be met in actual practice, regardless of whether --the injector is operating on exhaust or live steam.

The manner in which the above noted general objects and other and more detailed objects are attained may best be understood from the ensuing portion of this specification in which there is described by way of example, but without limitation, a preferred form of apparatus for carrying the invention into effect, such apparatus being more or less diagrammatically illustrated in the single figure of the accompanying drawing forming a part hereof. 7

Referring now more particularly to the drawing, the injector comprises a main casing or body it having a main low .pressure steam nozzle l2 formed in part by a stationary nozzle portion l2 on which is slidably mounted a. shroud nozzle M. A draft or water nozzle IB is mounted co-axially with the shroud nozzle l4 and co-axially with these nozzles there is provided the usual combining tube l8 and delivery tube 20. Delivery tube 20 communicates with the delivery chamber 22 of the injector which is in turn connected to the delivery conduit 24, the latter being provided with a suitable delivery check valve (not shown). The combining and delivery tubes also communicate with the usual overflow chamber 25. The combining tube is provided with a movable overflow flap 28 and in the present embodiment the overflow flap is controlled by a combined overflow valve and delivery pressure control arrangement of novel form. In this arrangement the overflow valve 30 is closed by delivery pressure through themedium of the pivoted lever 32 which at one end bears on the valve and which at its other end is connected to a plunger orpiston 34, the end of which is subject to delivery pressure in the chamber 22.

A loading pin 36 projects through a suitable opening in the head of valve 30 to contact the overflow flap 28, this pin having a suitable piston-like head slidably mounted in a bore 38 formed in valve 30. Loading pin 36 is resiliently held in projected position by means of a loading spring 40. 7

Water is admitted to the injector from the water supply conduit 42, the admission of water being controlled by the water valve 44 which is biased toward closed position by the valve spring 46 and which is adapted to be opened by the steam operated water valve piston 48 attached to the end of the valve stem and mounted in a suitable cylinder in the valve casing. The outlet side of the water valve is in communication with the water chamber 50 in the injector body, this latter chamber being in communication with the annular space between the shroud and draft nozzles l4 and I6 respectively. As will be evident'from the figure, the area of the opening for suitable for exhaust steam operation is available and closed when such steam is not available,

The outlet side of the valve 54 is placed in regulated communication with thelow pressure steam chamber 58 by means of thez regulati'ng valve 68 which is preferably, as shown in the drawing, of balanced construction. Chamber 58 is in communication with the main low pressure steam nozzle I2. A second low pressure steam chamber 62 is provided in the injector body, which chamber is in open and unregulated communication with the outlet side of the exhaust valve 54 andwhich is also,-by means of ports 64, in constant communication with the space around the draft nozzle I6.

A nozzle 66 for high pressure steam, which will be referred to as supplementary steam, is mounted co-axially with nozzle I2 and around this nozzle there is formed a chamber 68 for additional live steam, hereinafter referred to as auxiliary steam. The auxiliary steam chamber 68 is in communication with the low pressure steam chamber 58 by means of the annular opening 1 8 which, as will be seen from the drawing, is arranged so as to direct the discharge from cham-' ber 68 around the projecting end of the supplementary steam nozzle 66 into the main low pressure nozzle I2.

Live steam for operating the injector and the injector control system is supplied through conduit 12 leading from the boiler, this steam being under the control of the main control or starting valve indicated generally at 14. Valve 14 comprises a main valve head 16 formed on a hollow stem 18 having a balancing piston 88. pilot'valve 82 extends through the main valve head 16 and is attached to the starting and control handle 84. As will be apparent from the drawing, when the handle 84 is actuated it operates first to lift the pilot valve 82 from its seat. The pilot valve has a certain amount of lost motion relative to the valve head 16 so that further movement of handle 84 after the pilot valve has been opened will operate to open the main valve head 16.

The outlet side of the pilot valve is in communication by way of the hollow main valve stem 18 with the conduit 86 which is in communication with the water valve piston 48.

The outlet side of the main valve 16 communicates by way of conduit 88 with the automatic valve indicated generally at 98. The automatic valve 90 has a double seated head 92 interposed between valve seats 94 and 96 and adapted to seat against one or the other of these seats in alternation under the influence of steam pressures acting on piston 98. Conduit 88 is alsorin constant communication around the automatic valve 98 by way of the high pressure steam passage I88 with the supplementary steam nozzle 66. Under the control of the automatic valve the conduit 88 is selectively placed in communication with the steam chamber I82. Chamber I82 is in constant communication by means of'a fixed choke I84.

further placed in controlled communication with the auxiliary steam chamber 68 by means of the variable choke indicated generally at I85. This variable choke is preferably in the form of a balanced valve head I89, the stem I88 of which is interconnected by means of the gear I I8 and racks H2 and H4 with the shroud nozzle I4. Gear H8 is fixed to the control rod I I6 which is connected by any suitable linkage (not shown) to a suitable water control handle or the like in the cab of the locomotive, for manual regulation of the amount of water admitted to the injector. As will be apparent from the drawing, the connection between the variable choke valve head I06 and the and decrease to ether.

The conduit 86 leading from the starting valve to the water valve piston is also advantageously placed in communication with the steam conduit 88 by means of a small fixed choke I I8. The live steam conduit 88 is placed in communication with a relay valve indicated generally at I28 by means of a branch pipe I22. The rela valve comprises a double seated valve head I24, working between valve seats I28 and I28, and control piston I38. Piston I30 is provided with a port I32 adapted to place the chamber I34 below the piston in communication with the chamber I36 above the piston.

Chamber I38 of the relay valve, below the seat I26, is provided with a controlled atmospheric vent I48 and is in communication by way of pipe I42 with the chamber above the piston 98 of the automatic valve 98. It is also in communication by way of pipe I44 with the exhaust valve piston I46. It further communicates by means of port I48 with a chamber I58 in the exhaust valve body.

A vent valve I52 controlling an atmospheric vent opening I54 is provided with a head I56 located in chamber I58, this valve being biased toward open position by spring I58. The vent valve I52 controls a passage I68 which is in communication with the exhaust steam suppl pipe on the inlet side of the exhaust valve by way of passage I62 and which is also in communication with an exhaust steam pressure chamber I64, the upper wal1 of which is formed by a flexible diaphragm I66.

The upper chamber I36 of the relay valve is placed in controlled communication with the outlet side of the exhaust valve by means of pipe I68 and passage I18. Flow of steam through this channel is controlled by means of a needle valve I12 attached to the diaphragm I66.

Referring again to the control valve 68, the stem 68a, projects through the wall of the injector housing and is connected by means of a jaw connection to one arm of a lever I14 having a fixed pivot I16. A pin I18 attached at one end to a bellows-type diaphragm I88 bears against one arm of lever I14 in opposition to the valve stem 68a. The bellows I88 is located in a closed pressure chamber I92 which by means of the pipe I84 is placed in communication with the in-,

jector overflow chamber 26.

A second pin I86, secured to a second bellows diaphragm I88, bears against the arm of lever I14 on the side of the pivot opposite pin I18. Bellows I88 is located in a closed pressure chamber I98 which by means of pipe I92 is placed in communication with the pressure chamber I94 abovepiston 98 in the automatic valve 98, and

also is placed in co'mmunicationby way of pipe.

I42 with the lower chamber I38 of the relay valve I28.

A spring I98, bearing against the injector casing as an abutment, tends to move the valve 68 toward closed position.

In the position of the parts shown in the drawing, the injector is set for exhaust steam operation. The starting valve I4 being in open position permits high pressure live steam to pass through pilot valve 82 into the water valve control line 86, to the water valve piston 48 holding the water valve 44 in open position. The small choke port I I8 providing communication between the pipe 86 and the steam passage 88 in the injector, serves to permit clearance of condensate from the water valve control line and serves also to relieve the steam pressure on top of the piston 48 when the pilot valve 82 is being closed. The high pressure live steam entering through main valve head I6 into supply conduit 88 flows around the automatic valve 98 and through passage I88 to the supplementary steam nozzle 66. High pressure live steam also passes from conduit 88 by way of the branch pipe I22, chambers I34 and I38 in the relay valve I28 and pipe I42 to the chamber I94 above the piston 98 in the automatic valve 98. This valve, engaging seat 96, prevents flow of steam from the conduit 88 to the chamber [82 in the injector. At the same time high pressure steam flowing through pipe I92 to the bellows chamber I98 tends to compress bellows I88 and thereby turn lever I14 in clockwise direction so as to move valve 68 to the left toward open position, against the action of the spring I96.

Under the assumed conditions, exhaust steam at a pressure suitable for operating the injector is available in conduit 52 and this pressure transmitted through the channels I62 and I6!) to the diaphragm chamber I64 acts to close the valve H2. The high pressure steam admitted to chamber I34 of the relay valve I28 in passing through the leak port I32 in piston I38 to the upper chamber I36 of the relay valve thus cannot escape through the pipe I68 and passage I78, so that the resulting high pressure built up in chamber I36 holds the relay valve to the lower position shown in the drawing in which chambers I34 and I38 are in communication and the atmospheric vent I48 is closed. With the relay valve in this position the high pressure steam passes from the relay valve not only to pipe I42, but also through the connection I44 to the chamber below the exhaust valve operating piston I46, holding the latter against spring 84611. to a position corresponding to an openexhaust valve. The high pressure steam also passes to the chamber I58 and acts against spring I58 to hold the vent valve I52 in closed position.

Exhaust steam is admitted to chamber 58 in accordance with the position of regulating valve 68, the operation of which will be described later. From chamber 58, the exhaust steam flows to the main steam nozzle I2. With the exhaust-valve in open position, exhaust steam is also present in the chamber 62 and a certain restricted quantity of steam can flow from chamber 82 to chamber 58 through the small ports I98 formed in the web separating these chambers. The steam flowing through valve 68 may, for convenience, be referred to as the primary supply of low pressure steam. A secondary supply of low pressure steam flows to the nozzle system, to be condensed in the injector jet, through the openings 64 connecting chamber 62 with the space around the draft nozzle I6. I

When steam and water is first admitted, the usual overflow takes place through the overflow valve 38 which at this time is not loaded by delivery pressure. As soon as the jet is established, delivery pressure is'built up and the overflow valve is closed.

After the overflow valve is closed, overflow pressure is built up in chamber 26, which pressure is transmitted to diaphragm I88, tending to compress this diaphragm and actuate pin I18 in a direction opposing the action of pin I86 which moves in response to the pressure of the high pressure steam in chamber I98.

It will thus be seen that the position of valve 68, when the injector is in operation, is governed by thedifference in pressure between the injector overflow pressure and the pressure of the high pressure steam which for all practical purposes may be considered as boiler pressure.

As previously noted, one of the primary objectives of an exhaust steam injector is to condense the maximum amount of exhaust steam under any given set of operating conditions while at the same time so limiting the quantity condensed under the given conditions that unstable operation or spilling of the injector is avoided. In contrast with prior procedure involving the admission of exhaust steam to the injector nozzle system at different places, the present invention provides for a regulated primary supply of exhaust steam through the main nozzle, rather than the unregulated supply heretofore employed. By means of the use of a regulated primary exhaust steam supply, better operating characteristics are attained and it has been found that with the primary supply regulated, the secondary supply may readily be left unregulated, thus not requiring further complication of the apparatus to provide for regulation of the secondary supply.

Also, the invention achieves desired improved results through the regulation of the primary exhaust steam supply in response to the differential between boiler and overflow pressures. Overflow pressure is a, reliable and relatively very accurate indication of the stability of the injector at any given time, a rise in this pressure indicating relatively less stable operation. Ordinarily, decrease in stability of operation is caused by the admission of too much steam for the condensing capacity of the water being admitted at the time, such condensing capacity I being a function both of quantity of water and inlet water temperature. With the apparatus contemplated by the present invention, and assuming a constant boiler pressure, any change in operating conditions tending to decrease the stability of operation of the injector will result in movement of the regulating valve 68 toward its closed position to decrease the quantity of primary exhaust steam admitted to the injector.

It will be apparent that with the overflow flap 28 of the combining nozzle loaded by. delivery pressure, the degree of loading will vary directly with variations in the boiler pressure against which the injector delivers, and that if boiler pressure is relatively high, the injector will continue to operate Without spilling with a higher overflow pressure than if the boiler pressure is relatively low. Consequently, it is possible for the present injector to utilize more exhaust steam and operate with a higher overflow pressure when the boiler is at normal operating pressure than when the boiler pressure is sub-normal.

In order to enable the maximum amount of exhaust steam to be condensed when operating against normal boiler pressures, While at the same time enabling the injector to operate prop erly when delivering against lower pressures, the bellows I88 is provided, which operates to adjust the exhaust steam regulating valve 68 in opposition to the action of the bellow I88. The arrangement is such that when the boiler pressure is low and is reflected in a relatively low pressure in the chamber I98, the valve 68 is moved nearer to closed position by the action of the overflow pressure responsive bellows I88 than when the boiler pressure is high. A the latter pressure increases, bellows I88 operates to increase the steam admission opening through this valve. Thus, by making the regulated exhaust steam admission opening responsive to the differential between overflow and boiler pressures, improved operating characteristics for the injector are obtained over an increased range of boiler pressures against which the injector must deliver.

In the foregoing description the injector has been assumed to be operating on exhaust steam, with the parts in the positions shown in the drawing. Operation of the injector on live steam including the starting operation will now be described, it being understood that when operating as a live steam injector various parts of the control system will be in positions different from those shown in the drawing.

When starting the injector, it will be apparent that by moving the control valve handle to the open position shown in the drawing, the pilot will open first, permitting high pressure live steam to pass through conduit 86 to water valve piston 48 to open the water valve prior to the admission of the main supply of steam to the injector.

Movement of the starting valve to full open position causes admission of high pressure live steam to injector supply conduit 88. This will operate to admit high pressure live steam to the nozzle 66 and in this connection it is to be noted that regardless of whether the injector operates wholly on live steam or on exhaust steam a high pressure supply of supplementary live steam is furnished to the injector. As will be seen from the drawing, the high pressure steam conduit 88 is always in communication with the chamber I88 leading to nozzle 66, since movement of the valvehead 92 upon change-over from live steam operation to exhaust steam operation or vice versa does not affect the communication between conduit 88 and chamber I88. This continuous supply of supplementary high pressure live steam is used in order to supplement the action of the low pressure nozzles, whether the latter are supplied with exhaust steam or low pressure live steam, such supplementary action being required in an injector for feeding a high pressure boiler, in order to secure a delivery pressure equal to or greater than the boiler pressure.

After the injector has been started and feeds the boiler properly, a few seconds will elapse before the injector changes over from live steam operation to exhaust steam operation, provided there is exhaust steam pressure available. This time interval is obtained by the restricted steam admission through the leak port I32 in the piston I38 leading to the upper chamber I36 of the relay valve and pipe I68. If the pressure in this pipe, also called timing pipe, and the upper chamber I36 of the relay valve is much lower than the pressure in the steam chamber I34, the relay valve will be set differently from the position shown in the drawing. This position will also prevail when no exhaust steam, or exhaust steam of too low a pressure for proper exhaust steam operation is available, in which case valve I12 is not maintained closed by the pressure acting on diaphragm I66 in the exhaust valve assembly. With the chamber I36 vented or not yet under Working steam pressure, the relay valve member shifts to its upper position, in which case the head I24 seats against seat I26, thus blocking communication between chamber I34 and I38 and venting the latter chamber to atmosphere through the vent I48. This in turn prevents pressure from acting on the exhaust valve piston I46 so that the exhaust valve is held in closed position by exhaust valve spring I46a. Since there is no pressure in chamber I58, the vent valve I52 is held in open position by spring I58 which allows the exhaust steam passages on the inlet side of the exhaust steam valve to be vented.

The venting to atmosphere of chamber I38 of the relay valve also operates to vent pipes I42 and I92, thus obtaining atmospheric pressure above piston 98 of the automatic valve 98 and the bellows I8. When the pressure on bellows I88 is atmospheric, the exhaust steam regulating valve 68 is held in closed position by spring I86.

With the pressure being atmospheric in the chamber I94 above the piston of the automatic valve, the automatic valve member is held in its upper position, in which case the head 92 is away from seat 96 and seats against seat 84, thus establishing communication between the high pressure steam conduit 88 and the steam chamber I82 in the injector. From this latter chamber the high pressure steam flows through the fixed choke I84 into the steam chamber 62, from whence it can flow through the secondary low pressure steam ports 64 to the nozzl system of the injector and also in relatively small quantity through the series of ports I98 to the low pressure chamber 58. The steam flowing to the nozzle system of the injector through the choke I84 may conveniently be considered as the secondary auxiliary steam supply corresponding to the secondary exhaust steam supply flowing through ports 64 when the injector is operating on exhaust steam.

From chamber I82 auxiliary team, which may be considered as the primary auxiliary steam supply, flows through the variable choke I85 to chamber 68 and through passage 18 to the main nozzle.

Exhaust steam injectors when applied to locomotives have exhaust steam supplied thereto under difierent engine operating conditions which produce widely differing exhaust steam pressures, such pressure under some conditions being relatively high. If the injector is operating at full capacity with relatively cold water at times when relatively high pressure exhaust steam is available, this steam may be used in the injector at its relatively high pressure and in relatively large quantities and through proper regulation of the exhaust steam supply it has heretofore been possible to take advantage of the variations in exhaust steam pressure to give injectors of the type under consideration a relatively wide range of capacity while still maintaining good operating characteristics.

Heretoiore, however, the range of injector ops eration when operating wholly on live steam has been less than when operating on exhaust steam because of lack of proper control of and variation in the pressure of the auxiliary live steam admitted to the injector.

By the present arrangement, the deficiencies of prior injectors with respect to range of operation are obviated by the admission tothe injector of primary and secondary supplies of auxiliary steam, the primary supply of which is regulated so that when desired, the auxiliary steam may be supplied to the injector at relatively high pressure. In the present arrangement this is accomplished through the medium of the variable choke I05, the area of which is made such that when the choke is fully open, the primary supply of auxiliary steam is delivered to the injector at materially higher pressure than that representing prior practice.

The use of higher auxiliary steam pressure results in a further operating advantage when it is desired to operate the injector when boiler pressure is relatively very low. This occurs, for example, when it is desired to feed a boiler which is just being fired up and inwhich the boiler pressure is very much below normal. In prior forms of injectors, operating with relatively low auxiliary steam pressure when the boiler pressure is normal, sub-normal boiler pressure may result in the creation of sub-atmospheric pressure in the low pressure steam chamber of the injector. If under such conditions the exhaust steam valve is leaky, the partial vacuum in the steam chamber of the injector will draw air into the steam space of the injector through the leaky exhaust valve and cause the injector to break. With the present arrangement, auxiliary steam pressure above atmospheric can readily be maintained even if the boiler pressure is as low as only fifty percent of normal and the danger of drawing air into the injector thus eliminated.

Obviously, the maximum pressure at which auxiliary steam can be utilized in an injector, and the quantity as well, are dependent upon the amount of water being admitted to the injector and for this reason the variable auxiliary choke I is interconnected with the water control so as to be opened and closed as the water inlet is opened and closed.

The present arrangement for controlling the auxiliary steam supply to the injector results in so improving the range of operation of the injector when operating wholly on live steam that it is of the same order as that obtained with ex-- haust steam operation even in cases where exhaust steam is at times available and used at relatively high pressure. Consequently, with the present injector, adjustment by the operator is not required when the injector shifts from exhaust steam to live steam operation under conditions which heretofore would have required readjustment because of the fact that at the time of the shiftover the injector was operating on exhaust steam at a capacity beyond that which could be reached with live steam operation.

For injectors of the kind to which the present invention relates, which are particularly useful for feeding locomotive boilers, it is highly advantageous to construct the injectors as nearly symmetrical as possible with respect to their longitudinal, central, vertical plane. If the injectors are symmetrical about such as plane they are much more readily applied either right handed, or left handed on various different locomotives as occasion may require without resorting to special injector construction to permit application on one or the other side of the locomotive.

To this end the loading construction for the overflow chamber and flap of the combining nozzle disclosed herein is particularly advantageous, since by this construction, as will be clearly evident from the drawing, it is possible to arrange the overflow valve and loading apparatus along the central longitudinal plane of the injector, thus making it wholly symmetrical with respect to this plane.

From the foregoing description it will be apparent that many changes and modifications in design of the apparatus may be made without departing from the scope of the invention as defined in the appended claims.

What is claimed is:

1. In an exhaust steam injector having an overflow chamber, a nozzle system for creating and maintaining a jet in the injector including a main low pressure steam nozzle, and means for admitting exhaust steam to said nozzle, said means comprising a valve for controlling the flow of exhaust steam and valve actuating means responsive to overflow pressure and to a pressure indicative of and varying with the pressure against which the injector delivers, said valve actuating means being constructed and arranged. to position said valve in accordance with the differential pressure between said overflow and said indicative delivery pressures.

2. In an exhaust steam injector, a nozzle system for creating and maintaining a jet in the in jector including a main steam nozzle, an exhaust steam supply conduit, a valve controlling flow of steam from said conduit to said nozzle, an overflow chamber, a first pressure responsive element responsive to the pressure in said chamber, a second pressure responsive element responsive to steam pressure indicative of the boiler pressure against which the injector delivers, and means for transmitting motion from said pressure responsive elements to said valve, said means being arranged so that force derived from said first pressure responsive element tends to close said valve upon increase in overflow pressure and force derived from said second pressure responsive element tends to open said valve upon increase of said steam pressure.

3. In an exhaust steam injector, a nozzle system for creating and maintaining a jet in the injector including a main steam nozzle, an exhaust steam supply conduit, a valve controlling flow of steam from said conduit to said nozzle, a spring tending to close said valve, an overflow chamber, a first pressure responsive element responsive to pressure in said chamber, said element being arranged to transmit force to said valve tending to close it upon increase in pressure in said chamber, a second pressure responsive element responsive to pressure indicative of and varying with the pressure against which the injector delivers, and means for causing force from said second pressure responsive element to tend to'open said valve, in opposition to the forces from said spring and from the first pressure responsive element, upon increase in the pressure acting on the second pressure responsive element.

4. In an exhaust steam injector, a nozzle system for creating and maintaining a jet in the injector including a main steam nozzle, an exhaust steam supply conduit, a valve controlling flow of steam from said conduit to said nozzle, a spring tending to close said valve, an overflow chamber, a first pressure responsive element responsive to pressure in said'chamber, said element being arranged to transmit forceto said valve tending to close it upon increase in pressure in said chamber, a second pressure responsive element responsive to pressure indicative of the pressure against which the injector delivers, means for causing force from said second pressure responsive element to tend to open said valve in opposition to the forces from said spring and from the first pressure responsive element upon increase in the pressure acting on-the second pressure responsive element, and a lost motion connection between said valve and the first pressure responsive element, whereby to permit said spring to close said valve independently of the action of said first pressure responsive element when the second pressure responsive element is not subject to pressure.

5. In an exhaust steam injector of the type adapted to operate wholly on live steam when exhaust steam is not available, a main low pressure steam nozzle, a steam chamber in communication with said nozzle, a valve for controlling flow of steam to said chamber, an exhaust steam supply conduit leading to said valve, an overflow chamber, a high pressure steam'supply indicative of the pressure against which the injector delivers, a first pressure responsive element responsive to the pressure in said overflow chamber, said element acting on said valve and tending to close the valve upon increase in overflow pressure, a second pressure responsive element responsive to the pressure of said high pressure steam, said second pressure responsive element acting to open said valve upon increase in the pressure of said high pressure steam, an automatic control system responsive to the presence or absence of exhaust steam, said system including means automatically operable to admit said high pressure steam to said second pressure responsive element when exhaust steam suitable for operation of the injector is available and to relieve said second pressure responsive element from pressure when such'exhaust steam is not available, whereby to cause said valve to be controlled by the difference in pressure between overflow pressure and the pressure of the high pressure steam only when such exhaust steam is available.

6. In an exhaust steam injector of the type adapted to operate wholly on live steam when exhaust steam is not available, a main low pressure steam nozzle, a steam chamber in communication with said nozzle, a valve for controlling flow of steam to said chamber, a spring for closing said valve, an exhaust steam supply conduit leading to said valve, an overflow chamber, a high pressure live steam supply indicative of the pressure against which the injector delivers, a first pressure responsive element responsive to the pressure in said overflow chamber and tending to close said valve upon increase in overflow pressure, a second pressure responsive element responsive to the pressure of said high pressure steam, said second pressure responsive element acting in opposition to the forces of said spring and said first element and tending to open said valve upon increase in the pressure of said high pressure steam, an automatic control system responsive to the presence or absence of exhaust steam, said system including means automatically operable to admit said high pressure steam to said second pressure responsive element when exhaust steamsuitable for operation of the injector is available and to relieve said second pressure responsive element from pressure when such exhaust steam is not available-whereby to cause said valve to be controlled by the difference in pressure between overflow pressure an'dthe pressure of the high pressure steam when such exhaust steam is available, and a lost motion connection between saidfirst pressure responsive element and said valve, said connection permitting said valve to be closed by said spring independently of the value of overflow pressure whenever said second pressure responsive element is relieved from the pressure of said high pressure steam, and means for supplying live steam at reduced pressure from said high pressure live steam supply to said main low pressure steam nozzle when exhaust steam suitable for operation of the injector is not available.

7. In an exhaust steam injector of the type adapted to operate wholly on live steam when suitable exhaust steam is not available, a high pressure steam supply, a high pressure steam nozzle communicating with said supply, a regulable water supply nozzle and means for supplying additional live steam to said injector comprising a regulable choke valve in communication with said high pressure steam supply, said choke valve being interconnected with said regulable nozzle to decrease the area of the choke port as the area of the water supply opening is decreased and vice versa.

8. In an exhaust steam injector of the type adapted to operate Wholly on live'steam when suitable exhaust steam is not available, a high pressure steam supply, a high pressure steam nozzle communicating with said supply, a regulable water supply nozzle, a main low pressure steam nozzle, said nozzles cooperating to create and maintain a jet in the injector, and means for supplying live steam of variable pressure to said main steam nozzle comprising a regulable choke valve in communication with said high pressure steam supply, said choke valve being interconnected with said regulable nozzle to decrease the area ofthe choke port as the area of the water supply opening is decreased and vice versa.

9. In an exhauststeam injector of the type adapted to operate WhOIIy'On' live steam when suitable exhaust steam is not. available, a high pressure steam supply, a high pressure steam nozzle communicating with said supply, a regulable water supply nozzle, a main low pressure steam nozzle, a secondary steam nozzle, said noz-' zles cooperating to create and maintain a jet in the injector, means for supplying-primary auxiliary steam of variable pressure to said main steam'nozzle comprising a regulable choke valve in communication'with said high pressure supply, said choke valve being interconnected with said regulable nozzle to decrease the area of the choke port as the area of the water supply opening is decreased and vice versa, and meansfor supplying secondary auxiliary steam to said secondary nozzle comprising a steamspace communicating with said high. pressure supply through a choke port of fixed area.

10. In an exhaust steam injector, awater supply nozzle, a'main low pressure ste'am nozzle, 9. high pressure steam nozzle, said nozzles cooperating to create and maintain a jet in theinjector, a high pressure steam supply, an exhaust steam supply, a main exhaust steam shutoffyalve, a steam supply conduit connecting said main nozzle with the outlet side of saidshutoff valve, an exhaust steam regulating valve in said conduit, a

spring tending to close said regulating valve, pressure means responsive to pressure from said high pressure steam supply for opening said regulating Valve against said spring, an automatic valve shiftable under the influence of pressure from said high pressure supply from a first position admitting auxiliar live steam to the injector to a second position shutting oiT said auxiliary steam from the injector, a relay valve shiftable from a first position for admitting steam from said high pressure supply to said pressure responsive means and said automatic valve to a second position for venting said pressure responsive means and said automatic valve to a zone of low pressure, means for supplying steam from said high pressure supply to said relay valve to shift the same, and means responsive to the presence or absence of a suitable supply of exhaust steam for controlling the steam supplied to said relay valve to hold the relay valve in its first position when such a supply of exhaust steam is available and to hold said relay valve in its said second position when such a supply of exhaust steam is not available.

11. Apparatus as set forth in claim 10, in which said main exhaust valve is provided with pressure responsive means for opening the valve against a force tending to keep it closed, and a connection is provided between said pressure responsive means and the relay valve for supplying high pressure steam for opening said main valve only when said relay valve is in its said first position.

12. Apparatus as set forth in claim 10, in which means is provided for maintaining said main exhaust valve in closed position when said relay valve is in its said second position and in which a choke port is provided for admitting auxiliary live steam at reduced pressure to the portion of the exhaust steam conduit between said main exhaust valve and said exhaust steam regulating valve, whereby to maintain superatmospheric pressure in said portion of the conduit and prevent ingress of air to the nozzle system of the injector past a leaky main exhaust valve.

13. In an injector, a nozzle system having aligned nozzles including a fixed high pressure steam nozzle, a fixed main low pressure nozzle, a fixed secondary nozzle, an axially shiftable nozzle between said main nozzle and said secondary nozzle, means providing a water chamber the outlet of which is located between said shiftable nozzle and said secondary nozzle, the area of said outlet being governed by the positioned of said shiftable nozzle, said nozzles cooperating to create and maintain a jet in the injector, means providing a steam chamber around said high pressure steam nozzle, said chamber having an outlet for delivering steam toward said main nozzle, an axially shiftable choke valve member for admitting steam to said chamber, and a rotatably mounted water control member engaging both said axially shiftable nozzle and said choke valve member for simultaneously shifting the same toward their respective open or closed positions.

14. In an injector, an overflow chamber, a delivery chamber, a combining tube having its outlet located in said overflow chamber, said combining tube including a flap movable to increase the outlet area of the tube, an overflow valve for controlling overflow from the overflow chamber, means responsive to the pressure in said delivery chamber for closing said overflow valve, and means carried by said overflow valve for yieldably biasing said flap toward closed position.

15. In an injector, a body portion providing overflow and delivery chambers, combining and delivery tubes, said combining tube having its outlet located in said overflow chamber and including a pivoted flap movable to an open position to increase the outlet area of the combining tube, an overflow valve located adjacent to said flap and seating in a direction toward the flap, a flap engaging member carried by said valve and movable relative to the valve toward and away from said flap, and a spring carried by said valve for yieldably holding said member in engagement with said flap when said valve is closed, whereby to exert a closing pressure on the flap.

16. In an injector, a body portion providing generally aligned overflow and delivery chambers, a combining tube having its outlet located in said overflow chamber and having a pivoted flap movable to an open position for increasing the outlet area of the tube, a delivery tube generally aligned with said combining tube, an overflow valve located adjacent to said flap and seating in a direction toward the flap, a loading plunger mounted in said body portion and movable outwardly of the body under the influence of pressure in said delivery chamber, a lever pivotally mounted on the exterior of said body portion and arranged to engage said plunger and said valve for closing the valve under the influence of delivery pressure, and a spring loaded flap engaging member carried by said valve and movable relative to the valve for exerting a yieldable closing pressure on the flap when said valve is closed, the aforementioned movable parts being located in the longitudinal central plane of said body portion and substantially symmetrically with respect thereto.

17. An exhaust steam injector comprising a nozzle system including at least a primary nozzle for initially delivering exhaust steam into contact with the water supplied to the injector to establish a jet and a secondary nozzle for admitting additional exhaust steam to aid in the maintenance of said jet, means for admitting supplies of exhaust steam to said nozzles and regulating means for varying the flow of exhaust steam to said primary nozzle only, during the time when exhaust steam is admitted to said nozzles.

18. An exhaust steam injector comprising a nozzle system including at least a primary nozzle for initially delivering exhaust steam into contact with the Water supplied to the injector to establish a jet and a secondary nozzle for admitting additional exhaust steam to aid in the maintenance of said jet, and means for admitting supplies of exhaust steam to said nozzles, said means including a valve for regulating the steam supplied to said primary nozzle and port means of fixed area located to receive exhaust steam independently of the influence of said valve for admitting an unregulated steam supply to said secondary nozzle whenever exhaust steam is supplied to said nozzles.

ARTHUR WILLIAMS. ERICH HENKEL.

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