US1975506A - Exhaust steam injector - Google Patents

Description

Oct. 2, 1934. J. F. GRIFFIN EXHAUST STEAM INJECTOR Filed Jan. 2, 1931 I I l l l l I I l l ll.

lNVENTOR Joseph F. Griff n BY 6. V,

ATTORNEY Patented Oct. 2, 1934 UNITED STATES EXHAUST STEAM INJECTOR Joseph F. Griffin, Teaneck, N. J assignor to The Superheater Company, New York, N. Y.

Application January 2, 1931 Serial No. 506,106

.7 Claims. (01. 103-265) This invention relates to change-over mechanisms for exhaust steam injectors and other types of apparatus and aims to provide an ar-- rangement of greater reliability than that now 5 mostly used.

Double pressure steam injector arrangements using live and exhaust steam have been proposed adapted to automatically admit auxiliary steam from the boiler to the exhaust steam chamber of the injector whenever the pressure of the exhaust steam becomes insufiicient to maintain satisfactory operation of the injector. An arrangement adapted to operate in this way is disclosed in Patent #1,573,059, to Malcolm Hard. It has been found, however, in the operation of exhaust steam injectors that it is very difiicult to so design the exhaust steam nozzles that the injector will operate on as low a pressure of exhaust steam as is desirable and will also prevent the jet' from breaking at the pressures of exhaust steam occurring when the locomotive is developingits greatest horse-power output. As the periods of maximum load on the locomotive occur much more infrequently than those of low exhaust pressure, exhaust steam injectors are ordinarily so designed that they cease to operate properly at the maximum pressures of exhaust steam encountered in practice.

It is an object of the present invention to pro- .vide a change-over arrangement for exhaust steam injectors and other devicesrequiring an auxiliary steam supply and adapted toavoid the difficulty just mentioned by automatically substituting a source of fluid of substantially constant pressure for one of variable pressurejwhen the latter is too high.

In accordance with my invention, the exhaust steam injector or other apparatus is maintained in operation when the exhaust steam pressures are too high for use in the apparatus by auto- 1 matically substituting for the exhaust steam at such pressures the ordinary auxiliary steam supplied from the boiler, heretofore used only when the supply of exhaust steam has been either absent or abnormally low.

In order that myinvention may be clearly and easily understood, I willnow describe in detail, in connection with the accompanying drawing, a particular arrangement of an exhaust steam injector forming an illustrative embodiment of my invention. In said drawing,

Fig. 1 is an elevation of a locomotive having an exhaust steaminjector attached theretoj Fig'. 2 is a vertical sectional view thru the automatic valve appearing in Fig. 1 and used in accordance with my invention for controlling the change-over from exhaust steam to auxiliary steam under conditions of excess pressures of exhaust steam.

Referring to the drawing more in detail, 10 is I the boiler of a locomotive and 12 is a steam pipe carried thereby and connected into the steam space of said boiler for supplying steam to the ordinary auxiliary jet and for the ordinary supplemental steam supply of an exhaust steam injector 14. 16 is the engineer's valve in pipe 12 having a hand lever 18 whereby the injector 14 may be thrown into and out of operation. Steam which has been exhausted from the engine cylin-' ders is supplied to the injector 14 through a pipe 20 while the ordinary water supply pipe, overflow pipe and delivery pipe are indicated at 22, 24 and 26 respectively. In the ordinary operation of injector 14, live steam for the auxiliary jet is supplied from the boiler through pipe 12 and exhaust steam is supplied to injector 214 through the pipe 20. When, however, the exhaust pressure in pipe 20 falls below a certain point, the low pressure exhaust jets are unable to maintain the injector in operation. and. auxiliary live steam must be suppliedtothe exhaust steam chamber of injector 14. For this purpose, an automatic change-over mechanism is ordinarily employed, one form of which is illustrated in said patent to'I-Iard. The preferred arrangement, however, and the one shown in the drawing, is similar to that disclosed in the patent of Malcolm Hard, No. 1,870,006, August 2, 1932, reissued July 3, 1934, Re-issue No. 19,229,;for Exhaust steam injectors. In the arrangement illustrated herein, an automatic change-over valve will be understood to be used within the casing 28, such valve being adapted to control the port for supplying auxiliary steam from the live steam pipe 12 into the 9 exhaust steam chamber of injector 14 and also to control steam for closing a valve for cutting oif the exhaust steam chamber of the injector from the exhaust steam pipe 20 whenever. supplemental live steam is being used. The action v of the change-over valve in casing 28 will be'understood to be controlled by a relay valve also in casing 28, said relay valve being controlled in turn by a vent valve operated by a valve in the casing 30. The valve in casing 30 is controlled by a 9 diaphragm the under face of which is subject ordinarily to the exhaust steam pressure in the pipe 20 by exhaust steam supplied through pipe 32 having one end connected into the bottom of casing 30 and the other into the pipe 20. Whenever the exhaust steam pressure against the under face of the diaphragm in casing 30 falls below a given point, a spring in the casing moves the diaphragm in such casing downward so as to produce conditions in the casing 28 causing the operation of the relay valve to supply fluid to operate the change-over valve as above described. It will be understood that the foregoing description of the injector illustrated in Fig. 1 relates solely to injectors of the prior art which, while forming part of my novel combination, are not in themselves claimed. herein, and it will be understood further that I do not limit myself to the mechanism shown in either of said patents.

In accordance with my invention, if the pressure in pipe 20 reaches such a point that there is danger the injector 14 will go out of operation due to breaking of its jet, I vent the under surface of the diaphragm in casing 30 to atmosphere thereby producing such conditions in the changeover mechanism as cause it to switch from exhaust steam operation to auxiliary steam operation. For this purpose, I place in the pipe 32 a valve casing 34 which is illustrated in detail in Fig. 2. In the form shown, valve casing 34 comprises a central chamber 36 connecting through ports 38 and 40 with the chambers 42 and 44 respectively, lying one on each side of the chamber 36. Chamber 36 is connected directly with the under face of the diaphragm in casing 30, while chamber 42 is connected to the exhauststcam pipe 20, and chamber 44 is connected through the vent 46 with the atmosphere or otherplace of low pressure. A valve 48 is provided at the inlet end of port 38 which is normally open, but which isso arranged that when it is seated chamber 36 and diaphragm casing 30 are cut off from the exhaust steam pressure. A normally seated valve 50 is provided at the outlet of port 40 and so arranged that when it is seated, chamber 36 is cut off from the chamber 44 and from the atmosphere. Valves 48 and 50, however, are set in alignment and have projections 52 and 54 thereon arranged to contact and of such length that when valve 48 is seated, valve 50 is open and vice versa. Valves 48 and 50 are acted on by springs 56 and 58 respectively which thrust in opposite directions. Spring 58 is made suificiently stronger than spring 56 so that valve 50 is normally seated and valve 48 normally open. The exhaust steam pressure from pipe 20 is therefore normally free to pass into the diaphragm casing 30 as previously described. When, however, the pressure in pipe 20 rises above a certain predetermined value, spring 58 is no longer able to retain valve 50 on its seat against the combined thrusts of the steam pressure and that of spring 56 so that valve 50 opens connecting chamber 36 to the atmosphere through port 40, chamber 44 and vent 46. Spring 56, assisted by the rapid flow of steam past valve 48,--this velocity having increased due to venting through chamber 44 and vent 46thereupon promptly seats the'valve 48 cutting 01? the chamhaust steam pressure.

It will be seen also that the arrangement according to my invention has the further advantage of protecting the diaphragm in casing 30 against abnormal pressures either steam or hydrostatic.

It will be understood also that I do not limit myself to any particular form of valve or type of mechanism for producing the conditions setting in motion the change-over mechanism when the exhaust steam pressures reach abnormal value.

I claim:

1. The combination with an apparatus having a normal source of fluid supply of variable pressure and an auxiliary source of fluid supply and having automatic mechanism for shutting off said normal supply and for opening up said auxiliary supply when the pressure of the normal supply is below a predetermined minimum and adapted to restore connection to the normal supply and to cut off the auxiliary supply when the pressure of the normal supply has risen above said minimum, said mechanism including a connection to said normal source of supply, of automatic means for venting said connection to a region where the pressure is below said minimum only when the pressure of the normal source has risen above a predetermined maximum.

2. The combination as set forth in claim 1 and in which the venting means isconstructed and arranged to out 01f the connection between the automatic mechanism and the normal fluid supply at the time said connection is vented to the region whose pressure is below the predetermined minimum.

3. The combination with an injector having a supply of exhaust steam and an auxiliary steam supply and having automatic mechanism for shutting off said exhaust steam supply and for opening up said auxiliary supply when the pressure of the exhaust steam supply is below a predetermined minimum and adapted to restore connection to the exhaust steam supply and to cut off the auxiliary supply when the pressure of the exhaust steam supply has risen above said minimum, said mechanism including a connection to said exhaust steam supply, and automatic means for producing in said connection a pressure below said minimum when the pressure of said exhaust steam supply has risen above a predetermined maximum.

4. Thecombination as set forth in claim 3 and in which the means for producing the low pressure in the connection is constructed and ararranged to out 01f the exhaust steam from the ifo automatic mechanism when the exhaust steam I the minimum at which such mechanism shuts off the exhaust steam supply and opens up the auxiliary supply to the injector.

5. The combination of an apparatus having a normal source of fluid supply of variable pressure and an auxiliary source of fluid supply and having automatic mechanism for shutting off said normal supply and. for opening up said auxiliary supply when the pressure of the normal supply is below a predetermined minimum and adapted to restore connection to the normal supply and to cut off the auxiliary supply when the pressure of the normal supply has risen above said minimum, said mechanism including a connection to said normal source of supply, and automatic means for controlling said automatic mechanism to cause it to shut off said normal supply and to open up said auxiliary supply only its abnormal pressures from said source of a casing in said connection, a valve in said casing adapted when seated to interrupt communication between said source and said apparatus, said casing having a vent aperture, a valve arranged to close said aperture when seated, automatic means for holding said vent valve normally closed but adapted to yield only to abnormal pressures Within said casing, and means whereby said first mentioned valve closes when said vent valve opens and remains open when said vent valve is seated.

' JOSEPH F. GRIFFIN.

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