US1719070A - Charles j - Google Patents

Description

y 2, 1929- c. J. MILLER AUTOMATIC CONTROL VALVE Filed Sept. 1927 INVENTOR.

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Patented July 2, 1929.

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CHARLES J. MILLER,.OF IASSAIC, NEW JERSEY, ASSIGNOR TO THE SUPERHEA'IER COMPANY, OF NEW YORK, N. Y.

AUTOMATIC CONTROL VALVE.

Application filed september 2, 1927. Serial 110,217,116.

.My invention relates to automatic control valves and has for its general object the provision of a control valve for automatically preventing the starting or continued operation of steam driven pumping units when the load thereon fails. H

The invention is particularly applicable to high speed turbine driven centrifugal pumps, and I have, therefore illustrated a preferred form of my invention applied to a locomotive feed water pump of thistype, although it is to be understoodthat the invention may equally well be applied to many different forms of apparatus of this" general character. For purposes of illustration, I have shown I the invention in the accompanying drawings,

in which Fig. 1 is a fragmentary elevation of a locomotive provided with a feed pump equipped with an automatic control valve embodying my invention, and Fig. 2 is a diagrammatic sectional view on an enlarged scale through the control valve.

Referring now to Fig. 1, I have shown generally at 1 a steam turbine driven centrifugal pump to which water is supplied through the suction conduit 2, and from which boiler feed water is delivered under pressure through the discharge conduit 3 to the check valve (not shown) of the boiler.. Steam is supplied to the turbine end'of the pump from the boiler of the locomotive through the inlet conduit 1 in which is located, convenient to the operator, the throttle valve 5.

The control valve embodying my invention is located in the conduit between the pump turbine and the throttle valve 5, the

control valve being connected by means of conduit 6 with the discharge side of the pump. 7

Referring now to Fig. 2, I have shown the control valve as housed in a single integral casing 7, although it is to be understood that the severalparts of the valve may, if desired,

be housed in an assembly comprising a number of separate casings. 1 Y

The casing has'formed therein a steam inlet passage 8 receiving the main steam supply to the pump turbine, and'a main steam outlet passage 9 delivering steamthereto. Passages 8 and 9 are separated by a suitably ported web 10 and communication through in the passage connecting passage 8 with chamber13. The position of metering pin 18 is made adjustable, preferably by threading it into the casing 7, and extends to the exterior of the casing'so that adjustments in its position may be made. A cap 19 is preferably removably secured over the end of the .metering pin, and this cap as well as the casing 7 is provided with a suitable ring 20 adapted to receive a sealing wire.

At the end opposite the opening 17 the passage 16 is provided with a conical valve seat 21, and the casing 7 is formed to provide a cylindrical chamber 22 closed by cap 23 and in alignment with the seat 21. Chamber 22 is'ventedto the atmosphere at one end bythe port 24, and at the other end is placed in communication by means of passage 25 with the chamber 26, the latter communicating through the conduitG with the dis charge side of the pump.

A freely slidable valve member is mountec in the casing and comprises a piston 27 located in chamber 22 between the inlet passage 25 and vent 24, and a conically faced valve end 28 adapted to engage the seat 21 to close communication between passage 8 and chamber 14.

The inlet passage 8 is placed in communication with the opening 17 of passage 16 ,by means of-passages 28, 29 and 30 and another passage 31 connects passage 29 with passage 16 at a point intermediate'its ends. Passage 291s closed at one end by the plug 32, and has located therein between passages 28 and 30' the annular plug 33 having the valve seat 34 formed therein.

At its opposite end passage 29 is enlarged to form the chamber 26 closed by cap 35.

A Vaiy 11ien1 bQ1-aG is mounted inpas'sage 29 and provlalecl at and. sits piston piston 37.

The operation of the device is as follows: Assuming that it 1s desired to start the pump when water is available in the supply line leading thereto, the opening of the throttle valve 5 admits steam to the passage 8, and it will be apparent from the form of the valve member 11 that-the unbalanced steam pressures acting on the latter will force it to its open position as shown in the figure, and allow steam to flow to the pump turbine and start the latter; At" the sametime steam will-be admitted through passage 28 to the valve head 38, but'further flow oi the steam through passage 29 will be prevented by the seating 01 the valve head 38 under the influence of the pressure exerted by spring 10, the latter having sufficient strength to keep the valve closed against any steam pressure less than that required to maintain a pump discharge pressure of approximately lbs.

Steam also flows through passage 15 and past the metering pin 18 into passage 16, forcing th'evalve 28'to the right and flowing through passage 17 to chamber 13. The ad mission of steam to chamber 13 exerts a pressure on piston 12' which would overcome the unbalanced pressures on the valve member 11 and close the latter, thereby stopping the pump, it the full pressure passing through the valve were permitted to act on piston 12. Under the conditions assumed, however, that is, water present at the pump, the initial starting of the pump upon the opening of valve 11 will have caused a discharge presexerted by spring 40 so that the valve men'iber '36 is held inits extreme lettt-hand position,

and communication between passages 28 and 29 cut oil? even though the pressure in passage 28 rises to a point where it would, acting on the valve head '38, shift the valve member 36 to the right against the counter-pressure of spring lO'fllOIiG.

Itthere is no suction water present at the pump, and his attempted to start the latter, the action of the control valve will be substantially the same as that described except that due to the lack of water at the pump, no discharge pressure therefrom will be built up and communication between passages 16 and 17 will not be closed by the action of pump discharge pressure on piston 27. Steam will then continue to be admitted to piston 12, and the resulting pressure thereon will shift the valve 11 to its closed position before the pump has had an opportunity to reach a dangerous degree of speed because of the lack of load thereon.

Incase the 'pumpz'is operating normally, and the discharge pressure fails because of failure of a su'liicient ater supply to reach the pump, the pressure in chau'ibers 22 and 26 will be relieved. The gt'ailure of pressure in chamber 22 will permit piston 27 and with it valve 28 to move to the right and allow steam to close the valve 11 by acting on piston '12. However, if the pump atthe time of such iailure'were operating under a: substantial load it might be damaged from 'overspeedi'ng before valve llclosed, because. oi th'e time interval introduced by the restriction at the metering pin in the steam passage leading to piston 12.

In order to obviate such a possibility, the valve member 36 is provid .ed. If thepumpis operating under a substantial load, the steam presure in passage 28 is suiliciently high to overcome'the resistance of spring 10, and upon the failure of the pump discharge pressine'under thesecon'ditions, the valve member 36 isforced to the right against the spring 40. '1hisinov'ement oi the member 36 brings the recessed portion 39 into registry with the passages 30 and 31, so that they are placed in comn'iunication through the recess in member 36'. \Vith the member-36in this position, stean 'from the inlet passage 8 is bypassed around the restriction formed at the meteringpin and an unrestricted steam flow is established between the inlet'passage S and the piston 12. This tree steam flow to piston 12 assures the instant closing oil the valve member 11 in the event of failure of the pump 7 discharge pressure whenever the 17111111115 operating under a sufiicient head oisteam to actuate'the valve memberSG'. It the pump 15 operating undera lower headol steam than this, the flow of steam past the metering pin 18 to the piston 12 will be sutlici-ently' rapid to close the main valve before serious overspeeding occurs.

The time interval introduced by the metric tion' formed by the 'uetering pin13 is necessary in orderto allow the pump to start when water is present at the pump. A few seconds are re uiretl for the "min 3' tobuild n J a dis- 7 In order to prevent improper adjustment of the metering pin 18, I prefer to provide the cap' 19 with means for sealing it in position so that only those authorized to make the necessary adjustments may do so, and it unauthorized adjustment is made, it will be immediately apparent because of the broken seal.

I prefer to provide in connection with my control valve a compound gauge such as is shown at 41, equipped with one indicator hand 42 which registers the pressure in the inlet conduit 4 between the throttle 5 and the pump turbine, and a second hand -13 which registers the pump discharge pressure Under normal starting conditions, the hand 43 will rise to a point slightly above boiler pressure indicating that the pump is operating to feed the boiler, and the hand 42 will rise to a point somewhat below boiler pressure, the pressure indicated by hand 42 being indicative of the approximate capacity at which the pump is operating. If water is not present at the pump, and it is attempted to start the latter, the hand 43 will fail to rise and hand 42 will rise to approximately boiler pressure; thus giving immediate notice to the operator that the control valve has operated to stop the pump. When the pump is operating and the Water supply thereto fails, the action of the gauge will be of a similar nature, hand 43 dropping from a high pressure to zero and hand 42 rising from a point below boiler pressure to about boiler pressure.

Obviously, many changes in the apparatus I have shown as an illustrative example may be made, and it is therefore to be understood that theinvention is not to be limited to the form. shown, but is to be considered as embracing all forms that may fall within the scope of the appended claims.

I claim:

1. In apparatus of the class described, a fluid pressure operated prime mover, a pump driven thereby, a conduit connecting said prime mover with a fluid pressure source,

' a valve located in said conduit, fluid pressure actuated means for closing said valve, a connection leading from the inlet side of said valve to said means, and means actuated by the delivery pressure from said pump to close said connection, said connection being arranged to pass a predetermined quantity of steam at all times except when closed by said last named means. v

2. In apparatus of the class described a fluid pressure operated prime mover, a pump driventhereby, a conduit connecting said prime mover with a fluid pressure source, a valve located inv said conduit, fluid pressure actuated means for closing said valve, a connection leading from said conduit to said means, means for delaying the flow of fluid through said connection, means for bypassing said delaying means, and means actuated by the delivery pressure from said pump to close said connection.

3. In apparatus of the class described, a fluid pressure operated prime mover, a pump driven thereby, a conduit connecting said prime mover with a fluid pressure source, a valve controlling said conduit and opened by fluid pressure therein, fluid pressure actuated means for closing said valve against pressure in said conduit, a conduit connecting the inlet side of said valve with said means, said last-named conduit having a restriction therein, a valve closing said lastnamed conduit under the influence of pump discharge pressure, a normally closed bypass around said restriction, and means actuated by fluid pressure admitted to said control valve for opening said bypass under predetermined conditions.

4. In apparatus of the class described, a fluid pressure operated prime mover, a pump driven thereby, a conduit connecting said prime mover with a fluid pressure source, a valve controlling said conduit and opened by fluid pressure therein, fluid pressure actuated means for closing said valve against pressure in said conduit, a conduit connecting the inlet side of said valve with said means, said last-named conduit having a restriction therein, a valve closing said last-named conduit under the influence of pump discharge pressure, a bypass around said restriction,

means for controlling said bypass, means for closing said, controlling means under pump starting conditions, means utilizing pump discharge pressure to hold said controlling means in closed position, and means actuated by fluid from said source to open said controlling means when the pump discharge pressure fails.

5. In apparatus of the class described, a turbine, a pump driven thereby, a steam supply pipe leading to said turbine, a main valve controlling said pipe and opened by steam passing therethrough, a piston for closing said valve, a connection for adn'iitting steam from the inlet side of said valve to said pistion, a restriction in said connection, a valve operated by the discharge pressure from said pump to close said connection, a bypass around said restriction, a valve member con trolling said bypass, a spring urging said valve member to closed position, means actuated by steam admitted to said main valve for opening said valve member against said spring only when the steam pressure exceeds a predetermined amount and means actuated by the pump discharge pressure for holding said valve member in closed position against the action of said steam pressure actuated means.

6. An automatic control valve comprising a main valve initially opened by steam admitted thereto, means actuted by steam admitted to said valve for subsequently closing. and

means forming a passage open at all times and adapted to admit steam at a predetermined delayed rate to said first named means.

7. An automatic control valve comprising a main valve initially opened by steam admitted thereto, means actuated by steam admitted to said valve for subsequently closing it, means for admitting steam at a predetermined delayed rate to said first named means, 10 and means for bypassing said last named means.

CHARLES J. MILLER.

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