US2058028A

US2058028A - Throttle valve device

Info

Publication number: US2058028A
Application number: US660786A
Authority: US
Inventors: Joseph C Mccune
Original assignee: Westinghouse Air Brake Co
Current assignee: Westinghouse Air Brake Co
Priority date: 1933-03-15
Filing date: 1933-03-15
Publication date: 1936-10-20
Anticipated expiration: 1953-10-20

Description

" ocnzo, 1936.1 JQMCCUNE 2,058,028

THRAOTTL VALVE DEVICE Filed Maron .15, 1935 INVENTOR A TTORN Patented Oct. 20, 1936 UNITED 4STATES PATlez-NTA OFFICE:Y

THROTTLE-VALVE DEVICE V Joseph C. McCune, dgewoodga., 'vasjsignor to The Westinghouse Air Brake Company, Wilmerdng, Pa., a corporation ofl `Pennsylvania Application March 15, 1933,Serial No. 660,786

6 claims; (c1. 13d- 139) This invention relates to throttlevalve devices and particularly to valve devices for controlling the delivery of steam driven air compressors such as are employed on railway locomotives.

Locomotives equipped for supplying superheated steam to the driving cylinders and appurtenant apparatus of the locomotive are usually equipped with means for generating superheated steam as required and for regulating the temperf 10` ature of the steam delivered to the cylinders and appurtenant apparatus, so that when superheated steam is not required, saturated steam may be supplied to the driving cylinders, as when descending long grades where little or no power is required to maintain the speed of the train.

Because of the greater efciency of the superheated steam, the usual steam driven compressor is driven with greater rapidity when the superheated steam is supplied thereto than when op- 201 erated by saturated steam at like pressure.

Since the increase in speed of operation of theV compressor is unnecessary, the operation with superheated steam is wasteful unless the supply of superheated steam is throttled to maintain the desirable speed of operation. It is, therefore, advantageous to reduce the delivery of super-l heated steam to the engine of the compressor in accordance with the increase in temperature of the steam delivered, so that the compressor is 30. operated substantially at a constant speed regardless of whether saturated steam or superheated steam is supplied to the engine of the compressor.

An object of the invention is to provide a throttle valve devicev for a steam driven `air compressor and having means for automatically regulating the delivery of steam to the engine for operating the compressor so that the compressor will be driven at a uniform speed regardless ofr whether the engine is being supplied with-saturated steam or with superheated dry steam.

A further object of the invention isto'provide a throttle valve device having the above noted characteristics wherein a movable valve serves to 45 control the passage of steam through a by-passl passage, and which valve is operated by a thermally responsive bi-metal element and moved to closed position for closing the by-pass passage when superheated steam is being supplied tothe` 50, engine of the compressor.

A further-object of the invention is to providea throttle valve device for the purpose described, that may be placed in the steam conduit leading from the superheater of the locomotive to the 55l engine of: the. compressor `and which isprovided .a

withia permanently openpassage having a flow area of sufficient size to deliver the proper amount of superheated steam to the engine of the compressor formaintaining a predetermined` or desired operating speed thereof and which is 5'*- also provided with a by-pass and a normally open control valve therefor thatA is open when saturated steam is supplied tothe engine and whichV is automatically moved toward closed position as the temperature of the steam is increased, as '10" when superheated steam is delivered to the engine of the compressor, so that the quantity of steam `delivered to the engine is reduced when that steam is superheated.

.These and otherobjects of the invention that 15 will be madev apparent throughout the further description thereof are attained by means of the apparatus hereinafter described and illustrated in the 'accompanying drawing; wherein,

Fig. 1 is anelevational view of a steam driven 20 fluid icomprssor and theimproved throttle valve device associated therewith;

'Fig.f2 Vis -a longitudinal section through the throttle valve. device shown in Fig. 1, the throttle Valve A`device being, shown in the cold condition thereof, thatis without steam flowing therethrough; f

Fig. 3 is a transverse section through the throttle Valve device taken on the line 3-3 of Fig-...2: and Y c Fig. 4 is a fragmental sectional view taken on the line ll-llof v Fig. 3 showing the laminated construction of vthe loi-metal valve operating d evie.'v 35 Referringto the drawing, a standard steam driven air compressor `is. disclosed comprising a steam driven engine Il, a `huid compressor I2 that is driven by the; operating piston rod i3, and the improved throttle vvalve, device I4 that is 40 connected-inthe steamV supply pipe I5 which leads fromthesuperheater of the locomotive, not shown, to the engine Il.

The .throttle valve device comprises a casing lll havingfan inlet chamber IB and an outlet y chamber. l'l. separated by a partition wall I8 havingpaa permanently open steam passage i9 establishing communication between the inlet and outlet .chambers tti-andv I1 respectively. The flow area of the passage [Sl-may be altered as desired by inserting a screwplug 2| having an orifice 22, theflowarea oi which is of suiiicient size to permit the passage-oi` suztlicient steam to the engine of-'the compressor tof-maintain the desired and most 'advantageous-1 speedof V operation when 552 superheated steam is supplied to the engine from the locomotive superheater, not shown.

Since a greater quantity, by weight, of saturated steam must be supplied to the engine of the compressor to maintain a given speed of operation than when superheated steam is supplied thereto, it is necessary to provide an additional passage or by-pass for the flow of steam from the inlet chamber to the outlet chamber, so that suicient saturated steam may be supplied to the engine of the compressor through the passage |9 and the by-pass passage to maintain the desired operating speed of the compressor.

The by-pass passage comprises a chamber 23 in a bushing 20 and which is open to the chamber I6 through four passages 30, and passages 24 and 25 leading from the chamber 23 and opening into the chamber |1, the passage 24 opening into a passage 26 in the casing of the throttle valve device which leads from the chamber I1. The bushing 20 is centered in the chamber I6 so that two relatively large passages past the bushing from the inlet to the outlet side of chamber |6 are provided, as shown in Figure 3. A valve 21 within the chamber 23 and a valve 28 within the chamber |1 and connected by a uted stem 29 having a cylindrical portion 38, serve to close the passages 24 and 25 respectively when the valves are moved axially upwardly. The valves are pres- `sure balanced and are operated by means of a laminated bi-metal thermal element 3| that is mounted in a supporting member 32 that is secured within the chamber |1 of the casing. The valve 28 is provided with a flat extension 33 having a slot 34 in which the central portion of the bi-metal element 3| is disposed in such manner that when the bi-metal element 3| is bowed upwardly, as when the temperature thereof is increased, the valves 21 and 28 are moved toward closed position.

The rate of flow of steam through the by-pass passages 24 and' 25 is substantially constant, as the valves 21 and 28 are moved upwardly, until the valves reach a certain intermediate position, beyond which further movement thereof eiects a restriction or reduction in the rate of ilow of steam through the passages 24 and 25.

The expansion characteristics of the bi-metal thermal element 3| are such that the valves 21 and 28 do not reach the certain intermediate position as long as saturated steam is supplied through the throttle valve device, assuming that the saturated steam is below a certain pressure, the valves 21 and 28 being raised beyond the certain intermediate position only when superheated steam, at or above its minimum temperature for the same pressure as that of the saturated steam, which minimum temperature is higher than the temperature of the saturated steam, is supplied through the throttle valve device.

'I'he degree of reduction in the rate of ow of superheated steam through the by-pass passages 24 and 25 is substantially in direct proportion to the temperature of the superheated steam, and thus the rate of flow of superheated steam through the passages 24 andl 25 is reduced in inverse relation to the increase in the temperature of the superheated steam until a predetermined high temperature is attained at which the thermal element 3| has raised the valves 21 and 28 sufficiently to entirely close the passages 24 ,and 25 and completely cut oi the flow of superheated steam through the by-pass passages.

Thus, over a considerable range of temperatures between the minimum temperature and the predetermined high temperature of superheated steam, above mentioned, there is a regulation of the ow of superheated steam through the bypass passages 24 and 25, so that for a given load on the driving engine of the compressor there is substantially no change in the speed of operation of the driving engine with changes in the temperature of the superheated steam. Furthermore, since regulation of the flow of superheated steam begins substantially at the minimum temperature thereof, there is substantially no change in the speed of operation of the driving engine of the compressor for a given load thereon, when superheated steam is supplied through the throttle valve device as compared to that when saturated steam is supplied through the throttle valve device.

If the temperature of the superheated steam increases above the predetermined high temperature there is, of course, no regulation of the ow of superheated steam, but the range of temperatures 4of superheated steam over which the throttle valve device is effective to regulate the ow of superheated steam is calculated to take care of the usual operating temperatures of superheated steam employed.

The casing of the throttle valve device is provided with a cover 31 for closing the opening 35 in the chamber |1, through which opening the valves 21 and 28, stem 29 and thermal element 3| are inserted during assembly of the valve device. Suitable union pipe connections 36 are also provided for eiecting steam-tight joints between the casing and the pipe.

In operation, assuming the compressor engine and the steam supply pipe to be cold, and' that because of the cold condition of the apparatus, saturated steam is initially supplied to the pipe l5 and to the throttle valve device i4 and the compressor engine the valves 21 and 28 are in the open position and saturated steam is supplied to the engine of the compressor through passage I9 and through the by-pass passages 24 andl 25.

As the bi-metal element 3| bows upwardly, the valves 21 and 28 are raised to their intermediate position in the manner previously described, the permanently open passage |9 andv the open bypass passages permitting the proper amount of saturated steam to ilow to the engine for op-erating the engine at the desired speed.

When superheated steam is supplied to the pipe I5 and to the throttle valve device, the bi-metal element 3| is heated above the minimum temperature of superheated steam for the pressure employed and is caused to bow further upwardly to effect further upward movement of the valves 21 and 28, thereby reducing the flow area of the bypass passages 24 and 25, in the manner above described, and correspondingly reducing the quantity of steam supplied to the engine so that the speed of operation of the compressor is maintained substantially constant for a given load thereon.

If the temperature of the superheated steam be reduced to that of saturated steam, as when the locomotive is descending a long grade and saturated steam is then supplied to the pipe |5 and the engine the temperature of the bi-metal element 3| will be correspondingly reduced, and as it assumes its normal position, it moves the valves 21 and 28 toward open position, thereby increasing the iiow area of the by-pass passage and permitting a greater quantity of saturated steam to ow to the compressor engines and maintain proper operating speed thereof. It will be. understood that the expansion characteristics of. the bi-metal element 3| may be such that as the temperature of the steam varies between that of saturated steam and superheated dry steam, the quantity f steam supplied to the compressor engine is regulated to maintain a constant operating speed.

While the device is disclosed as applied to the steam engine of a fluid compressor, it is obvious that the throttle valve device may be used for regulating the delivery of steam to other steam driven apparatus for maintaining a constant speed of operation thereof regardless of variations in the temperature of the steam delivered thereto.

While but one embodiment of. the invention is disclosed, it is .obvious that additions and omissions and other changes may be made in the structure without departing from the spirit of the invention.

Having now described my invention, what I claim as new and desire to secure by Letters Patent, is:

1. A temperature regulated steam throttle valve device comprising a casing having an inlet chamber and an outlet chamber, a valve portion mounted for removal through the bottom of said casing between said two chambers and having two passages therethrough for establishing communication between said chambers through which steam may flow, one of said passages being permanently open and adapted to permit a relatively large flow of. steam to be maintained therethrough, a valve for closing the other passage, and a thermal responsive element for actuating said valve into closing position only upon a predetermined temperature of the steam flowing through said chambers.

2. A temperature regulated steam throttle valve device comprising a casing having an inlet chamber and an outlet chamber, a valve portion mounted for removal through the bottom of. said casing betwn said chambers and enclosing a valve chamber having a passage communicating with said inlet chamber, a constantly open passage for effecting communication between said valve chamber and said outlet chamber, and bypass passages for effecting communication from said valve chamber to said outlet chamber, a valve for closing the by-pass passages, and a thermal responsive element for actuating said valve into closing position upon a predetermined increase in temperature of the steam flowing through said chambers.

3. A temperature regulated steam throttle valve device comprising a casing having an inlet chamber and an outlet chamber, a valve portion enclosing a valve chamber removably mounted in said casing between said inlet and outlet chambers providing permanently open dividing passages between said outlet and said inlet chambers about said valve portion, a passage for effecting communication between said valve chamber and said outlet chamber, and a by-pass passage for effecting communication from said valve chamber to said outlet chamber, a valve for closing the by-pass passage, and a thermal responsive element for actuating said valve into closing position upon a predetermined temperature of the steam flowing through said chambers.

4. A temperature regulated steam throttle valve device comprising a casing having an inlet chamber and an outlet chamber, a valve portion removably mounted in said casing between said inlet and outlet chambers and enclosing a valve chamber, passages for effecting constant open communication between said inlet and outlet chambers, a passage for effecting constant communication between said inlet chamber and said valve chamber, and by-pass passages leading in the opposite directions from said valve chamber for effecting communication with said outlet chamber, pressure balanced valves for closing said by-pass passages, and a thermal responsive element in said outlet chamber for actuating said valves into closing position upon a predetermined increase in the temperature of the steam flowing` through said chambers.

5. A temperature regulating steam throttle valve device comprising a casing having an inlet chamber and an outlet chamber separated by a partition wall, a valve portion extending through said wall and comprising a bushing enclosing a central chamber and having a bore therethrough forming by-pass passages leading from said central chamber to said outlet chamber, pressure balanced valves for closing said by-pass passages having a common stem positioned in said bore, and a thermal responsive element in said casing for actuating said valve into closing position upon a predetermined temperature of the steam owing through said chamber.

6. A temperature regulated steam throttling device through which saturated steam at a given pressure and corresponding temperature and superheated steam at substantially the same pressure but above a predetermined higher temperature than that of the saturated steam is supplied at different times, comprising a casing having an inlet chamber and .outlet chamber, a valve portion enclosing a valve chamber removably mounted in said casing between said inlet and outlet chambers providing permanently open divided passages between said outlet and inlet chambers about said valve portion, a passage for effecting communication between said valve chamber and said outlet chamber, and a by-pass passage for effecting communication from said valve chamber to said .outlet chamber, a valve for closing said by-pass passage, and a thermal responsive element subject to the heat of the steam flowing through the throttling device for actuating said valve into closing position upon a predetermined temperature of steam iiowing therethrough, said thermal responsive element being adjusted to operate the said valve device to reduce the flow of only superheated steam in relation to the temperature of the superheated steam above the predetermined temperature, said thermal responsive device being ineffective to so operate the valve device and to reduce the flow of saturated steam.

JOSEPH C. MCCUNE.