US1733259A - Exhaust-steam injector - Google Patents

Description

J. F. GRIFFIN Oct. 29, 1929.

EXHAUST STEAM INJECTOR Filed March 5, 1927 2 Sheets-Sheet R mv m m M W a 5 F H p E 5 A TT ORNE Y.

J. F. GRIFFIN EXHAUST STEAM INJECTOR Filed March 3, 1927 2 Sheets-Sheet IN V EN TOR. g e/FFlM JOSEPH F A TTORNEY Oct. 29, 1929.

Patented Oct. 29, 1929 UNITED STATES PATENT OFFICE JOSEPH F. GRIFFIN, F TEANECK, NEW JERSEY, ASSIGNOR TO THE SUPERHEATER CSMPANY, OF NEW YGRK, N. Y.

EXHAUST-STEAM INJECTOR Application filed March 3, 1927.

My invention relates to exhaust steam injectors of the type primarily intended for operation by exhaust steam from an engine, and which may be operated entirely by live steam when exhaust steam is not available.

In injectors of this type, a small quantity of high pressure live steam, hereinafter referred to as supplementary steam, is used at all times when the injector is in operation either in conjunction with exhaust steam or with low pressure live steam, hereinafter referred to as auxiliary steam, the auxiliary steam taking the place of exhaust steam when the latter is not available.

The low pressure auxiliary steam is obtained by throttling steam from the high pressure source, and in the earlier forms of injectors the auxiliary steam supply was hand-controlled, the control valve forming the medium by which the pressure of the live steam was reduced.

In more recent examples of injectors of this type, the exhaust and auxiliary steam supplies are controlled by an automatic valve which admits them in alternation only. Such automatic valves, however, do not perform a throttling function with respect to the auxiliary steam and it has therefore been necessary to incorporate in such systems a choke or similar restriction at some point in the auxiliary steam supply line.

The proper throttling of the auxiliary steam supply is vital to the satisfactory operation of the injector, and the amount of throttling required is affected both by conditions under which the injector operates and by the amount of supplementary steam used as determined by the size of the supplementary steam nozzle.

In the past considerable difiiculty has been experienced in service with injectors of this character because of the necessity of providing a different size of restriction or choke for the auxiliary steam for different sizes of supplementary steam nozzles, and the principal object of the present invention is the provision of a control system for the injector in which the size of the auxiliary steam choke is determined by the proportions of the supplementary steam nozzle, so that upon the Serial No. 172,395.

removal of a supplementary steam nozzle and replacement with another nozzle of different size, the auxiliary steam choke will be varied to suit the requirements of the nozzle installed.

A further object of the invention is the provision of an automatic valve which will operate with the auxiliary steam choke placed between the automatic valve and steam chambar of the injector rather than between the automatic valve and the source of high pressure steam. A still further object of the invention is the provision of a control system with the auxiliary steam choke placed at the injector, whereby if the automatic valve is placed in a position remote from the injector the auxiliary steam may be led to the latter at high pressure and through a conduit of comparatively small diameter. Other and more detailed objects of the invention and advantages to be derived from the use thereof will become apparent from the ensuing description of a preferred form of the invention as illustrated in the accompanying drawings in which Fig. 1 is a fragmentary composite section taken through the center line of an injector and along the line 1-1 of Fig. 3. Fig. 2 is a fragmentary section taken along the line 22 of Fig. 3. Fig. 3 is a diagrammatic representation of the injector shown in Fig. 1, including the entire control system, and modified to show in a single plane the main injector and the water and automatic valve mechanisms. Fig. 4 is a fragmentary section of a modified form of supplementary steam nozzle.

The control system disclosed is with the exception of the automatic valve construction the same as that shown in the co-pending application of Neal T. McKee, Serial Number 172,367 filed concurrently herewith, to which reference may be had for a complete detailed description of the control system.

Referring now to Fig. 3, the injector proper comprises a housing 1 forming a main low pressure steam chamber 2 to which exhaust steam is admitted through a conduit attached at inlet 3, the flow of exhaust steam being controlled by the exhaust valve 4. Auxiliary steam, when exhaust steam is not available, is

admitted to the chamber 2 through the passage 5 and the annular port 6, the latter of which will be described in detail hereinafter. Exhaust or auxiliary steam, as the case may be, passes from chamber 2 to the main steam nozzle 7 in which is centrally located the supplementary steam nozzle 8 supplied with high pressure steam through the passage 9. Steam delivered through nozzle 7 combines with water supplied through chamber 10 in the water nozzle or cone 11, from which it passes through a secondary low pressure steam nozzle 12 to the combining and delivery tubes of the injector (not shown). The exhaust valve 4 controlling the exhaust steam supply is opened by means of the fluid pressure actuated piston 13 located within cylinder 14 carried by the injector housing, the latter also forming a passage 15 leading from the cylinder 14 through the chamber 2. The valve 4 is moved to closed position by the spring 16, the closing action of which is supplemented by the pressure of exhaust steam admitted through inlet 3.

As the injector structure just briefly described is of a well-known form, a further detailed description of the constructional features thereof is not deemed necessary to an understanding of the present invention.

The main control valve, which, when the injector is applied to a locomotive, is located in or adjacent to the cab thereof comprises a housing 16 formed with an inlet 17 to which live steam is delivered at boiler pressure from the turret of the locomotive. A housing 16 forms a pair of steam chambers 18 and 19, the former in communication with the live steam inlet 17 and the latter in communication with the live steam conduit 20 leading to the injector. Chambers 18 and 19 are connected by port 21, the circumference of which forms a valve seat against which the single main control valve 22 seats to close the port andrthereby shut off all live steam to the injector. Valve 22 is provided with an alongated stem 23 passing through a suitable stufiing box 24 to the exterior of the housing 16 Where it is connected to a suitable control lever 25 by means of which the main control valve 22 is manually operated. A second port 26 is formed in the housing 16 in alignment with port 21, and this port is controlled by valve 27 which is attached by means of a lost motion connection with an extension 28 of the valve 22, said extension passing through port 21. The port 26 provides communication between the chamber 19 and an intercepting valve which will be referred to later. The live steam conduit 20 is attached to the injector nearthe water valve actuating means. The waterv valve is mounted in a housing 29 which in Fig. 1 has been shown as cast integral with the injector housing 1. Obviously this portion of the housing may equally well be a separate casing bolted to the side of the injector, and as indicated in Fig. 3, the housing 29 is a separate element which, however, preferably forms a unitary assembly with the main body of the injector. As shown more clearly in Fig. 3, the housing 29 forms a water inlet chamber 30 to which water is admitted from a suitable source of supply (not shown), and an outlet passage 31 leading to the water chamber 10 of the injector, the connection being shown in the diagrammatic representation in Fig. 3 by way of conduit 32. Chamber 30 and passage 31 are connected by port 33, the circumference of which forms a valve seat against which the water valve 34 closes to shut off the water supply to the injector. Valve 34 is provided on its upper face with an annular rib for the retention of the spring 35 held in a suitable housing cab 36 and serving to urge the water valve to closed position. i The bottom of the water valve housing 29 forms a steam chamber 37 in communication with the conduit 20, and this chamber is placed in communication with a second steam chamber 38 by a port 39in alignment with port 33. Steam chamber 38 is separated from the water passage 31 by a web which forms a valve stem guide 40 in alignment with ports 33 and 39, and which has an open-ended cylindrical recess 41 formed below guide 40. Valve 34 is provided with a downwardly extending stem 42 which passes through guide 40 and has attached to its lower end a piston 43 which, when valve 34 is seated, is located in the port 39. Piston 43 is made a sliding fit. in. port 39 and, as will be obvious from the figure, the latter port is closed when the water valve is in its closed position. This form of water Valve actu ating means in which the flow of live steam to the injector is prevented until after the water valve is opened is not essential to the present invention, and a form such as is shown in my application, Serial Number 172396 filed concurrently herewith, may be substituted in its stead.

The automatic valve is provided for the purpose of automatically shifting the injector from live steam to exhaust steam operation or vice versa, and in the present instance the automatic valve has been. shown as located in an extension of the housing 29 which forms an integral assembly with the main housing 1 of the injector. It is to be understood, however, that in so far as the present invention is concerned, the automatic valve may be located in the control system at a point remote from the injector as, for example, in the disclosure of the United States Patent 1,574,798, granted March 2, 1926, to Hans Deutsch. The automatic valve portion of the housing 29 comprises three aligned chambers 44, and 46, chambers 44 and 45 being connected by port 47 and chambers 45 and 46 being connected by port 48, the latter being in alignment with port 47. Chamber 44: is in direct communication with chamber 38 and is provided with an outlet communicatin with the auxiliary steam passage 5 of the injector by way of the passage or conduit 51, and in addition port 52 is placed in communication with the steam passage 9 of the injector by means of a passage or conduit 58. The area of port 52 is adjustable by means of valve 54 extending through the housing to the exterior thereof. The automatic valve member 57 comprises a lower head 58 having oppositely disposed valve faces 58 and 58 which seat against similar faces formed around ports l? and 50. The

- upper portion of the automatic valve forms a piston 59 located in the port 48 and loosely fitted therein to permit some steam leakage therethrough. In this connection it is par ticularly to be noted that the piston portion 59 of the automatic valve member is considerably larger in diameter than the lower head portion 58.

A check valve 60 located in chamber 46 seats around the upper edge of port 48 and a small clearance is provided between the bottom of the check valve and the top of the automatic valve when both are seated in their lower positions.

Chamber a5 is placed in communication with the passage 15 of the injector by means of passage or conduit 56 and chamber as is connected by means of conduit 62 with the intercepting valve.

The intercepting valve comprises a housing' 63 attached to the main control valve housing 16 and forming a pair or chambers 64 and 65, the latter in communication with chamber 19 by way of the valve controlled port 26 and the former in communication with the conduit 62. Chambers 64 and 65 are placed in communication by port 66, around which there is formed within the chamber Get a valve seat. At the opposite end of chamber 6% there is provided a steam inlet connected by means of pipe 67 with a steam supply line of the engine from which the injector is supplied with exhaust steam, and a valve seat is provided around this inlet. Chamber 65 is provic ed with an atmospheric vent pipe '68 I entering the chamber adjacent to the port 66.

The intercepting valve member 69 comprises a valve head 70 formed with oppositely disposed valve faces 70 and 70 and adapted to move to seat against one or the other of the corresponding valve seats provided in cham ber 64C to close either port 66 or the live steam inlet 67.

The valve head 70 is connected to a suitably packed piston 71 mounted on the cylindrical chamber 65 between port 26 and vent 68. This connection is formed by valve stem passing through port 66, said stem being considerably smaller in diameter than the port.

Referring again to the injector proper, it will be noted that the auxiliary steam supplied through passage 5 passes into the steam chamber 2 through the circular port 6 through which also passes the supplementary steam nozzle 8, the latter being removably secured in the injector housing 1 by means of a suitable threaded connection.

It will be obvious that by varying the outer diameter of the nozzle 8 where it passes through the opening formed by the port 6 the size of the latter may be correspondingly varied. The restriction formed between the outer surface of the nozzle and the walls of the port 6 acts as the choke for the auxiliary live steam which is admitted to the passage 5 at high pressure and which passes into the chamber 2 at a pressure determined by the size of the free area of the port 6. By means of this arrangement each size of supplementary steam nozzle, which requires a dii'lerent opening for the auxiliary steam choke, may be made to form, when it is inserted in the injector, a choke suitable for the size of the nozzle merely by forming the nozzle with an outside diameter of the proper dimension.

In some cases where because of unusual op erating conditions it cannot be certainly determined in advance the exact size of choke which should be used, a modified form of supplementary steam nozzle such as is shown in Fig. l may be employed. In this case the port 6 leading from the supplementary steam passage 5 is formed with a taper bore and the supplementary steam nozzle 8 is provided with a correspondingly tapered shoulder 8 at the point where the nozzle passes through port 6'. The nozzle is threaded into the web of the injector housing 1 in the usual manner except that a washer 72 is inserted be tween the web of the housing and a suitable shoulder on the nozzle, and it will be readily apparent that by varying the thickness of the washer 72 the opening of the choke port 6' may be varied. In practice, I prefer to form the shoulder 8 so that with a so-called standard washer in place the choke opening will be of the proper size for the nozzle used, but in case the predetermined choke opening does not prove satisfactory in service, it may be varied by the use of a washer either thinner or thicker than the standard washer as the individual case may require.

lVherever it i possible I prefer to use the straight cylindrical form of nozzle, as the opening may be more accurately determined by the use of this form than in the case where the size of the opening depends upon the longitudinal position of the nozzle.

The operation of the apparatus is as follows: Assuming that the engine is operating and exhaust steam is available, the automatic valve will be in the position shown in Fig. 3 and the check valve 60 will be held to its seat as shown in the figure by the pressure of live steam admitted to chamber 46 through conduits 67 and 62 and chamber 64, the intercepting valve being forced to the position shown in the figure. by steam pressure in chamber 64. Movement of the control lever 25 from closed to open position opens the vmain control valve 22, but not the valve 27 which is kept on its seat by pressure of steam chamber 38 to chamber 44. From chamber 44 steam passes through the port 52 and passages 53 and 9 to the supplementary steam nozzle 8. Steam also passes from chamber 44 through the open port 47 and passages 56 and 15 to piston 13 which is actuated thereby to open the exhaust valve 4 and admit exhaust steam to the steam chamber 2.

r If now with the injector operating on exhaust steam, the engine is shut off and the exhaust steam supply fails, the automatic valve immediately shifts to its upper position being permitted to do so by the failure of the steam supply passing through conduits 67 and 62 to chamber 46. Vihen the pressure in chamber 46 drops, the check valve 60 is raised by the pressure of steam which has leaked past piston 59, and is trapped between the latter and valve 60. Upon the release of this pressure the pressure of the live steam in chamber acting on the undersides of piston 59 and valve 58 forces the latter up ward until the valve face 56 seats to close port 47. This movement of the automatic valve simultaneously opens the outlet and allows steam to pas through passages 51 and 5 and port 6 to the steam chamber 2 of the injector, the steam flow through port 6 serving to reduce the pressure of the steam ad mitted to chamber 2 by a throttling action. The shifting of the automatic valve to its upper position, by closing port 47, also cuts off the supply of steam leading to the exhaust valve actuating piston 13 which permits the exhaust valve 4 to close under the action of spring 16 and prevents the escape of auxiliary live steam from chamber 2 through the exhaust steam supply line leading to the injector.

If when the injector is operating on auxiliary live steam the engine is again started and exhaust steam becomes available, the inject-or is again shifted to exhaust steam operation by the action of the automatic valve. This shifting of the automatic valve is accomplished by the pressure of steam admitted to chamber 46 through conduits 67 and 62. With the automatic valve in its upper position, the check valve is lifted mechanically from its seat by the upper end of the automatic valve, and steam entering chamber 46 and acting on the upper face of piston 59 forces the automatic valve to its lower seat, thereby shutting off the auxiliary steam supply to the injector and opening port 47 so that steam can flow to the exhaust valve actuating piston. As the automatic valve is forced to its lower seat, the check valve 60 drops toits seat and is held thereon by the pressure of steam in chamber 46. Steam admitted to chamber 45 through the open port 47 passes around piston 59 and builds up a pressure in the chamber formed between the upper face of piston 59 and the lower face of check valve 60 so that piston 59 becomes balanced and the automatic valve is held in its lower position by the pressure of steam acting on the unbalanced areas of the valve. 7

l/Vith the auxiliary steam choke located between the automatic valve and the steam chamber of the injector, it is necessary for the piston 59 to be made materially larger than the valve head 58, for with the automatic valve in its upper position the entire lower face of this valve is exposed to high pressure steam admitted to chamber 44 through the steam supply conduit 20. The steam connection leading from the locomotive turret to chamber 44 is comparatively unrestricted and the steam pressure in this chamber is, therefore, very little if any below boiler pressure. The steam admitted to chamber 46 is taken from the supply line leading to the locomotive engine, and due to the comparatively small conduits used and the fact that the steam is taken from a point in the engine supply line beyond the throttle, this steam in many cases is materially below boiler pressure before it reaches the automatic valve chamber 46. In order, therefore, for this steam to overcome the high pressure existing under the valve head 58, it is necessary that the piston 59 be of larger diameter than the valve head.

The intercepting valve mechanism is used in order to provide a so-called emergency position which is brought into use when the operating lever 25 is pulled beyond the open position, so that valve 27 is lifted from its seat and steam is admitted to the piston 71. Steamacting on piston 71 shifts the valve 70 to close the steam inlet from conduit 67 and vents conduit 62 to the atmosphere by way of vent 68. As will be readily apparent, with the intercepting valve in this position, live steam cannot be admitted to the automatic valve to force it to its lower position and the injector will, therefore, operate on live steam irrespective of engine conditions.

As previously pointed out, the use of the supplementary steam nozzle as an auxiliary steam choke is not dependent upon the specific details of the control system except for the proper proportioning of the elements of'the automatic valve, and the location of the automatic valve may be either at the inject-or or at a point remote therefrom. In cases where the automatic valve is placed at a point remote from the injector, the use of the supplementary steam nozzle as a choke has the further advantage of permitting the connection between the automatic valve and the injector passage 5 to be made through a small conduit, as the steam passing from the automatic valve to the injector is under high pres sure and of comparatively small volume, whereas the placing of the choke ahead of the automatic valve, as is ordinarily done at present, necessitates the use of a large conduit to carry the low pressure auxiliary steam from the automatic valve to the injector.

It will be obvious from the foregoing description that many changes may be made in the form and arrangement of the several elements forming the injector and control system without departin from the spirit of the present invention, which is to be limited only by the scope of the appended claims.

What I claim is:

1. An exhaust steam injector of the type wherein an auxiliary live steam conduit communicates with the steam chamber of the injector through an orifice defined by a portion of the wall of said conduit and a nozzle through which supplemen ary live steam is admitted to the injector, characterized by said supplementary live steam nozzle being detachable and having a portion of its exterior surface formed relative to the size of the jet of said nozzle to define with a portion of the wall of said conduit, a restricted opening the size of which is predetermined according to the jet opening of said supplementary live steam nozzle, said opening serving to determine the amount of pressure reduction of the steam passing from said conduit to said chamher.

2. An exhaust steam injector of the type wherein an auxiliary live steam conduit communicates with the steam chamber of the injector through an annular orifice defined between an aperture in the wall of said conduit and a nozzle through which supplementary live steam is admitted to the injector, characterized by said supplementary live steam nozzle being detachable and having its outer diameter proportioned relatively to the size of the jet of said nozzle to define with said aperture an annular opening, the size of which is less than the smallest sectional area of said conduit and which is predetermined according to the jet opening of said supplementary live steam nozzle.

3. An exhaust steam injector of the type wherein an auxiliary live steam conduit communicates with the steam chamber of the injector through an annular orifice defined be tween an aperture in the wall of said conduit and a nozzle through which supplementary live steam is admitted to the injector, characterized by said supplementary live steam nozzle being detachable and having its outer diameter proportioned relatively to the size of the jet of said nozzle to define with said aperture an annular opening, the size of which is predetermined according to the jet opening of said supplementary live steam nozzle, and said annular opening being constricted to throttle the pressure of high pressure live steam admitted through said auxiliary live steam conduit to said opening.

4. An exhaust steam injector of the type wherein an auxiliary live steam conduit communicates with the steam chamber of the injector through an annular orifice defined between an aperture in the wall of said conduit and a nozzle through which supplementary live steam is admitted to the injector, characterized by said supplementary live steam nozzle being detachable and having a conical outer surface proportioned relatively to the size of the jet of said nozzle to define with said aperture a restricted annular opening to throttle the pressure of the high pressure live steam admitted through said conduit to said opening, the size of said opening being predetermined according to the jet opening of said supplementary live steam nozzle, and the provision of means for adjusting the lon gitudinal position of said supplementary live steam nozzle to vary the area of said annular openin b JOSEPH F. GRIFFIN.

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