US2228269A - Injector - Google Patents

Description

EL HENKEL Jan. 14, 1941.

INJECTOR Filed Aug. 26, .1939 2 Sheets-Sheet l INVENTOR ERIC/f HEN/(EL.

ATTORNEY Patented Jan. 14, 1941 PATENT QFFECE INJECTOR Erich Henkel, Calumet City, 111., assignor to The Super-heater Company, New York, N. Y.

Application August 26,

23 Claims.

This application is a continuation in part with respect to and replaces my co-pending application Serial No. 203,808, filed April 23, 1938, and later abandoned, and relates back thereto as to all common subject matter.

The present invention relates to steam injectors and more particularly relates to exhaust steam injectors, that is, injectors to which low pressure exhaust steam, supplemented by a sup ply of high pressure steam, is utilized to form the jet for injecting water against relatively high back pressures of the order encountered in feeding steam boilers. Still more particularly the invention relates to steam injectors of the kind used for supplying feed water to locomotive boilers and the invention will be described in its application to an injector of this kind. It will be understood, however, that the invention is not limited in its application to injectors of the particular kind hereinafter to be described by way of example.

Injectors for supplying feed water to locomotive boilers must operate under highly variable conditions such as variations in live steam pressure, which in turn results in variations in the pressure against which the injector must deliver; Variations in quantity and pressure of exhaust steam available, in the case of exhaust steam injectors; and variations in the temperature of the suction water supplied to the injector.

All of these factors materially affect the capacity and operating range of a given injector and in the case of exhaust steam injectors these factors also affect the quantity of exhaust steam which the injectors can condense and the fuel saving that can be effected by the injectors, which is one of the primary reasons for the employment of this type of injector.

Among the principal objects of the present in vention are to increase the delivery pressure obtainable with steam injectors, particularly exhaust steam injectors, and to increase the stability of operation of such injectors so that stable operation thereof is obtainable over a wider range of capacity than heretofore, even under relatively adverse conditions such as those obtaining when the suction water available is relatively warm. The accomplishment of the above and other and more detailed objects of the invention, together with advantages derived from its use, may best be understood from the ensuing portion of this specification taken in conjunction with the accompanying drawings showing suitable apparatus for carrying the invention into effect.

In the drawings:

Fig, 1 is a more or less diagrammatic sectional 1939, Serial No. 292,102

view of an exhaust steam injector and appurtenant apparatus embodying the invention;

Fig. 2 is a section taken on the line 2-2 of Fig. 1;

Fig. 3 is a section on enlarged scale of part of 5 the apparatus shown in Fig. 1;

Fig. 4 is a view partly in elevation and partly in section showing a variation of a part of the apparatus shown in Fig. 1;

Fig. 5 is a View showing a variation in the form 10 of the control for the apparatus shown in Fig. 1;

Fig, 6 is a view similar to Fig. 1 showing another arrangement embodying the invention;

Fig. 7 is a section on enlarged scale of a part of the apparatus shown in Fig. 6; and

Fig. 8 is a fragmentary section showing a variation of the arrangement illustrated in Fig. 6.

Referring now to Fig. 1, the injector illustrated is of the well known Metcalfe type of exhaust steam injector for feeding a locomotive boiler and 29 comprises a casing indicated generally at iii, to i one end of which is connected the conduit [2 for delivering to the injector exhaust steam from the engine of the locomotive, and from which the delivery conduit lEi leads to the usual boiler check 25 valve (not shown).

Exhaust steam from conduit I 2 flows to the main steam chamber l4 and through the main steam nozzle [6. Water is supplied to the injector through the water supply conduit [8 which 30 communicates with the Water nozzle 26. The jet 1 formed in the injector passes through the combining tube 22 and delivery tube 24 to the delivery conduit l5. Control of the capacity of the injector is effected in known manner by shifting nozzle It with respect to nozzle 20, by means of the eccentric control pin 26.

Live steam for operating the injector is supplied through conduit 28' leading from the boiler turret (not shown) and flow of such steam to the injector is controlled by any suitable form of manually operable valve indicated generally at 3t.

A part of the live steam supplied through conduit 28 flows to chamber 32 (see Fig. 2) which communicates with the high pressure or supplementary steam nozzle 34 which projects into the main or low pressure steam nozzle I6.

Another portion of the high pressure live steam is under some conditions permitted to flow through a suitable choke to the chamber 36 which 59 is in communication with the main low pressure steam chamber I4. This part of the live steam supply is reduced in pressure in passing through such choke and constitutes an auxiliary steam supply for use in lieu of exhaust steam when it is desired to operate the injector with the engine of the locomotive not running and consequently not supplying exhaust steam. The admission of auxiliary live steam in alternation with exhaust steam is under the control of a changeover valve indicated generally at 38.

All of the construction hereinabove described is of well known character and need not further be described herein for an understanding of the present invention.

In the apparatus illustrated, a supply of hot water under pressure is delivered to the supplementary steam. In the example shown, this Water is taken directly from the boiler fed by the injector. A portion of such boiler is indicated in Fig. 1, the crown of the firebox being shown at to and the water space at the rear of the firebox being indicated at 42.

Water is taken from this space through the tap 44 under control of the manually operated valve 46. The hot water is supplied through a conduit 48 in which there is advantageously located a strainer 50 and in which there is further located, in the embodiment shown, the valve 52, later to be described in detail. The conduit 48 terminates in a spray nozzle 56 provided with one or more jet openings 58 which serve to spray the hot water into the high pressure supplementary steam before this steam is supplied to the supplementary nozzle 34. As shown in Figs. 1 and 2, this spray nozzle is conveniently attached to the body of the injector so as to spray the water into the supplementary steam passage 32.

Valve 52 operates as an automatic shut-off valve for cutting ofi the supply of hot water under predetermined operating conditions. This valve comprises a housing 50 providing a valve seat 62 for a valve head 64 which when seated serves to close communication between the outlet of the hot water conduit 48 and chamber 56 which is in communication with the bore 68 of the spray nozzle 56. The valve head 64 is connected to a piston 10 operating in a chamber of the valve housing 60 and loaded by means of spring 12 which tends to keep the valve in the closed position shown in Fig. 3. The face of piston HI opposed to the face on which spring 12 acts, is placed in communication by pipe 14 with the live steam conduit 28 on the outlet side of the main injector control valve 3d. The strength of spring 12 is such that its resistance is overcome and the valve opened when live steam is admitted to start operation of the injector.

We will now consider the mode of operation of the apparatus just described and its effect upon injector operation. As previously noted, adverse operating conditions, such for example as hot suction water, materially reduce the capacity range of an injector, particularly an exhaust steam injector delivering against relatively high back pressures.

I have discovered that in operation of steam injectors a peculiar phenomenon occurs, the

reason for which has not yet been definitely established by me. This phenomenon operates to increase the stability of operation of the injector when the moisture content of the steam,

- particularly the high pressure steam, is increased,

and the stability of operation, under a given set of operating conditions, continues to improve until the amount of water injected reaches a very substantial value when compared to the quantity of steam into which it is injected. By way of example I have found by test that under certainconditions the improvement in stability of operation of the injector, as reflected by overflow chamber pressure, continues to increase with increase in percentage of water injected into the supplementary steam supply of an injector of the kind under discussion until the weight of water injected is equal to or even exceeds the amount, by weight, of the steam into which it is being injected. In some cases, improvement has been noted in exhaust steam injector operation with water injected into the supplementary steam supply until the moisture content thereof has become as high as 65% by weight, Obviously, under the widely varying conditions met with in injector operation, the maximum amount of water that can be mixed with the steam will vary but I have observed from test operation that the maximum amount of water that can advantageously be employed is very readily determinable by the injector operator, since if the proper maximum moisture content of the steam is exceeded because of supplying of too much water to it, the injector will commence to pulsate and this in turn will result some spilling at the overflow. Conditions productive of such spilling occur, however, before conditions arise which are likely to cause the injector to break and cease operation.

In the embodiment illustrated in Fig. 1 it will be observed that the main control of the operation of the injector is by means of valve 30 and separate from the control of the supply of hot water, which is controlled by the valve 48. In order to avoid any possibility of loss of hot water from the boiler when the injector is not in operation, due to the operator closing valve 3!! and forgetting to close valve 46, the shut-off valve 52 is ply which is at the same pressure as the source of supply of the steam into which the water is injected It might appear that the water could not be injected into the steam under conditions of this kind but in the type of installation illustrated it has been found from experience that the pressure drop between the source of steam and the interior of the injector close to the inlet of the steam nozzle is greater than the pressure drop occurring in the line supplying the hot water to be injected, and that there is sufiicient pressure differential between water and steam at the injector to permit the wate to be injected in the manner desired.

In some types of installation, however, this condition may not exist and in such case a different form of construction, of the kind shown in Fig. 4, may advantageously be employed. As illustrated in this figure, the water supplied through the conduit E8 is introduced through orifices 92 located at the throat 94 of the Venturi tube 96 interposed in the steam line leading to the injectorand serving to provide a place of reduced steam pressure. With such an arrangement, a suitable pressure differential between steam and water can be insured under all normal conditions of injector operation.

The control of the hot pressure water supply to the injector may in some instances advantageously be coordinated with the control of the main steam supply which governs periods of operation of the injector and in Fig. 5 a suitable arrangement for the combined control is illustrated. In this arrangement the control of the main steam supply through conduit 28 is effected by" the main control valve 30 which is opened and closed by movement of the pivoted arm 98, to one end of which is attached the manually operable control handle IN]. The hot water supply conduit 43 in this instance has located therein a stop valve I02 of any suitable type, advantageously a rotary plug type valve of known kind, the operating arm I04 of which is connected as by means of link I06: to the operating mechanism for opening and closing valve 30. Preferably the connection is made adjustable as shown at I08 for proper initial adjustment of the two valves so that when the valve 30 is closed the valve I02 also will be closed. It will be understood, of course, that in the usual operation of the main control valve 30 this valve is either fully opened or fully closed and consequently valve I02 will operate between fully opened and fully closed positions. Preferred initial adjustment is, however, such that when the control is moved from closed position toward open position, the valve Hi2 opens somewhat ahead of the opening of the main steam valve 30. This insures water reaching the injector ahead of steam when the injector is started, which is the most desirable sequence for prompt and reliable starting with minimum loss at the injector overflow before the jet is established and delivery commences.

It will be evident that the maximum quantity of hot pressure water added to the steam supply for the purpose of increasing the moisture content of the steam before it is combined with the suction water in the injector, will vary with different installations, depending upon the steam and water conditions and also the capacity and delivery pressure conditions for which the individual injector is intended to operate. Thisdesired maximum quantity may readily be determined in any individual instance either through the provision of a suitable choke in the conduit 48 or by the dimensions of the orifices through which the water is sprayed into the steam, since these orifices in themselves will operate as chokes.

In an installation of the kind described it is preferable to insulate the hot water supply conduit 48, not only to avoid loss of useful heat but also to obtain water for injection into the steam at as nearly as possible the saturation temperature of the steam. To this end if the hot water is, as in the illustrated embodiment, taken from the boiler which the injector feeds, it is advantageous to take the supply of hot water from a level in the boiler not far below the minimum working water level and at a place remote from the place of entry of feed water to the boiler. By so locating the place where the hot water is taken off, possibility of taking water appreciably below saturation temperature of the steam is substantially eliminated.

When the water for injection into the steam supply to the injector is taken from the boiler, and particularly when it is taken from the above described location, such water will be relatively free from scale-producing salts becauseof the precipitation thereof having already been effected in the boiler. This is of considerable advantage in some installations, particularly on locomotives where the quality of the feed water supply is not good.

In other cases, however, the feed water supply for the boiler may be relatively pure and free from scale-forming impurities and in such instances the water to be added to the steam supply to the-injector advantageously may be taken from the delivery of the injector. An arrangement of this kind is shown in Fig. 6, wherein the invention is shown applied to an injector of the same kind illustrated in Fig. 1 and wherein like reference numerals designate corresponding parts.

The present arrangement differs from the arrangement illustrated in Fig. lin that the spray nozzle 56 for injecting water into the steam supplied to chamber 32 is connected by means of a conduit H0, the inlet end of which is in communication with the delivery chamber H2 of the injector. Conduit H0 is preferably provided with a strainer 50 and is further advantageously provided with a choke member l i l. (see Fig. 7) interposed between the strainer and the spray. nozzle 55.

With this arrangement, the pressure available for forcing the water through the spray nozzle is always greater than the pressure of the steam in chamber 32 since the delivery pressure of the water from the injector must obviously be higher than boiler pressure if the water is to be fed to the boiler. The choke member H4 provides a ready means of controlling in desired manner the quantity of water delivered by the spray nozzle, through the choice of a choke having the proper size of orifice. Such a member is, however, not essential since the number and size of the. orifices in the spray nozzle itself may be used to determine the quantity of water injected. A separate choke member is to be preferred, however, since it provides a ready and convenient means for determining the amount of water injected, as circumstances of each individual installation may dictate.

As shown in Fig. 6, the inlet of the water supply conduit l0 is preferably placed in communication with the delivery of'the injector on theai inlet side of the injector delivery valve H5, al,-' though in so far as the present invention is concerned, the inlet of the water conduit may communicate with the delivery line of the injector at any place on the inlet side of the boiler check.

injector control valve 3i), the supply of water w.

injected into the steam. going to the injector is also automatically cut off. Conversely, when operation of the injector is started by opening the main injector control valve, water is automatically injected into the steam supply as soon as the injector jet is established and delivery pressure is built up by the injector. This enables a simpler construction to be used and it is also to be noted that with this construction, the water injected into the steam supply to the injector is at high temperature, having been heated by condensation of steam in the injector. The water supply pipe H0 is advantageously insulated, although this pipe is ordinarily so short that heat lost by radiation from the pipe is relatively slight and the need for insulation is not so great as would be the case in an arrangement of the kind shown in Fig. 1 where the hot water for injection is supplied from a relatively remote source.

The reason for the desirability of placing the inlet of the water supply pipe H in communication with the injector delivery on the inlet side of the injector delivery valve is to insure as far as possible the prevention of leakage of 5 water into the injector through pipe N0 when the injector is shut oif. Theoretically such leakage would be prevented by the boiler check valve in an arrangement such as that shown in Fig. 8, but in practice it has been found from experil0 ence that boiler check valves frequently become leaky in service and in the arrangement shown in Fig. 6, both the boiler check valve and the injector delivery valve would have to be leaky before water could pass from the boiler to the 0 supply pipe Ill] during inactive periods.

For the purposes of this specification and the appended claims, it is to be understood that the term delivery line includes all that portion of the injector subject to delivery pressure as well as the delivery conduit leading from the injector.

From the foregoing description it will be evident that the broad principle of the invention, which contemplates improving injector operation by providing the injector with a supply of steam for condensation within the injector to form the jet, which steam has relatively very high moisture content, may be applied in many different specific ways and to many different kinds and types of injectors. The invention is therefore not to be considered as limited to either the'particular type of apparatus or the particular mode of operation hereinbefore described by way of example, but is to be considered as embracing all forms of apparatus and modes of injector operation falling within the scope of the appended claims when they are construed as broadly as is consistent with the state of the prior art.

40 What is claimed is:

1. In the operation of a steam injector of the forcing type to which steam is supplied to be condensed by contact with the main water supply to form the injector jet, that improvement which consists in introducing water into said steam before it reaches the jet forming zone of contact condensation to increase the moisture content of the steam.

2. In the operation of a steam injector of the 0 forcing type to which saturated live steam is supplied for condensation within the injector, that improvement which consists in mixing hot water with said steam before it reaches the jet forming zone of contact condensation to substantially increase its moisture content.

3. In the operation of a steam injector of the forcing type, that improvement which consists in supplying suction water to the injector, supplying a. commingled high pressure steam and water mixture to the injector and producing the injector jet by condensationof said steam and water mixture with the suction water in the injector.

' 4. In the operation of a steam injector for supplying feed water to a boiler, that improvement which consists in supplying suction Water to the injector, supplying saturated steam from a steam space of the boiler to the injector for condensation with the suction water to produce the injector jet, Withdrawing water from the boiler at substantially the saturation temperature of the steam and introducing water so withdrawn into the steam supply to the injector, whereby to substantially increase the moisture content thereof before the steam is brought into condensing contact with the suction water in the injector.

5. In the operation of a steam injector of the forcing type, that improvement which includes the step of supplying water to a steam supply 5 for the injector to provide a steam and water mixture having at least a 50% moisture content by weight for contact condensation with the suction water supplied to the injector.

6. In the operation of a steam injector for 10 supplying feed water to a boiler, that improvement which consists in utilizing live steam from the boiler to produce a jet by condensation with suction water in the injector, withdrawing a supply of hot water under pressure from the boiler, 15 utilizing the flow of said steam from the boiler to establish a zone of reduced steam pressure in advance of entry of said steam into the steam nozzle of the injector and increasing the moisture content of said steam by introducing there- 20 into at said zone of reduced pressure the said water withdrawn from the boiler.

'7. In the operation of an exhaust steam injector of the forcing type having a supplementary high pressure steam supply, that improve- 25 ment which consists in increasing the moisture content of the supplementary steam supply by introducing water thereinto before the steam reaches the jet forming contact condensation zone in the injector. 30

8. In a steam injector of the forcing type, means for producing an injector jet including a steam nozzle and a conduit for supplying steam to said nozzle, and conduit means for supplying hot water under pressure to the steam supply 3 conduit for mixture with steam therein before it reaches said steam nozzle.

9. In a steam injector of the forcing type, means for supplying suction water to the injector, means for'supplying high pressure live 40 steam to said injector to be condensed by contact with the suction water, and means provid ing a connection for introducing water into said high pressure live steam prior to condensation thereof by contact with the suction water. 45

10. In an exhaust steam injector of the forcing type, means for delivering a main water supply to the injector, means for supplying low pressure steam to the injector, means for supplying supplementary high pressure live steam to the in- 5 jector. said low pressure steam and said supplementary high pressure live steam being delivered to a jet forming zone in the injector for contact condensation by the main water supply, and means providing a connection for introducing 55 water into said supplementary high pressure live steam to substantially increase its moisture content before the steam reaches said jet forming zone.

11. The combination, with a boiler and a steam 6Q injector for supplying feed water to the boiler, of a connection leading from the steam space of the boiler to the injector for supplying operating steam to the injector, and a connection leading from the water space of the boiler for supplying 65 hot water under pressure to said high pressure live steam prior to condensation thereof in the injector.

12. In the operation of a steam injector of the forcing type, that improvement which consists 7 in spraying hot water into operating steam supplied to the injector prior to contact condensation of such steam with the main water supply to the injector.

13. In a steam injector, conduit means for 75 supplying operating steam to the injector, a control valve in said conduit means for governing the admission of said operating steam to the injector, means for supplying hot water to said conduit means to increase the moisture content of the steam supplied to the injector therethrough, a stop valve in the water supplying means, and means responsive to the pressure in said conduit means on the outlet side of said control valve for causing said stop valve to close automatically when the supply of steam to the injector is shut off by said control valve.

14. In a steam injector of the forcing type, conduit means for supplying operating steam to the injector, a main control valve located in said conduit means, conduit means for supplying water to said operating steam to increase its moisture content prior to its contact condensation with the main water supply to the injector, a valve in the last mentioned conduit means for controlling the flow of said water to the injector, and manually operable means for opening and closing said valves in unison.

15. In a steam injector of the forcing type, conduit means for conducting live operating steam to the injector, a spray nozzle located to spray water into the steam passing through said conduit means prior to contact condensation of the steam with the main water supply to the injector, and means for supplying said nozzle with hot water under pressure whereby to increase the moisture content of said steam.

16. In a steam injector for supplying feed water to a boiler, a conduit leading from the boiler to the injector for supplying operating steam thereto, means providing a constriction in said conduit for reducing the static pressure of the steam therein at said constriction, means for introducing water into the steam in said conduit at the place where the steam pressure is reduced due to said constriction, and a conduit leading from the water space of the boiler to supply said water.

17. In the operation of a steam injector of the forcing type to which steam is supplied to be condensed by contact with water supplied to the injector to form the injector jet and from which water is delivered under pressure, that improvement which consists in mixing with said steam before it reaches the jet-forming zone a portion of the water delivered by the injector, whereby to increase the moisture content of said steam.

18. In the operation of a boiler feeding steam injector of the forcing type to which steam from the boiler is supplied to be condensed by contact with water supplied to the injector to form the injector jet and from which feed water is delivered to the boiler at a pressure greater than boiler pressure, that improvement which consists in diverting a portion of the feed water delivered by the injector and mixing the diverted water with said steam before the steam reaches the jet-forming zone, whereby to increase the moisture content of the steam.

19. In a steam injector of the forcing type, means for delivering a jet-forming water supply to the injector, means for supplying steam for contact condensation with said water supply to form the jet, and means providing a connection for introducing a portion of the water delivered by the injector into said steam prior to its contact with the jet-forming water.

20. A steam injector including a jet-forming steam nozzle, a steam supply passage communi eating with said nozzle, a water supply passage communicating with the outlet of said nozzle, a delivery line leading from the injector, and a conduit for supplying from said delivery line to said steam supply passage for mixture with the steam supplied to said nozzle a portion of the water delivered by the injector.

21. A steam injector including a jet-forming steam nozzle, a steam supply passage communicating with said nozzle, a water supply passage communicating with the outlet of said nozzle, a delivery line leading from the injector, a conduit for supplying from said delivery line to said steam supply passage for mixture with the steam supplied to said nozzle a portion of the water delivered by the injector, and a choke in said conduit for determining the quantity of water supplied through the conduit relative to the quantity of water delivered by the injector.

22. A steam injector including a steam nozzle, a steam supply passage communicating with said nozzle, a water supply passage communicating with the outlet of said nozzle, a delivery chamher, a delivery check valve, and a conduit having an inlet communicating with said delivery chamber on the inlet side of said delivery valve for supplying water from said chamber to said steam supply passage for mixture with the steam therein.

23. The combination with a feed water delivery line having a boiler check valve, a steam injector for supplying feed water through said check valve, of steam and water passages for supplying operating steam and water to the injector, and a conduit having an inlet communicating with said delivery line on the inlet side of said check valve for supplying to said steam supply passage for mixture with the steam therein a portion of the water delivered by the injector to said delivery line.

ERICH HENKEL.

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