US2345379A - Drain valve mechanism - Google Patents

Description

March 28, 1944. CAMPBELL 2,345,379

DRAIN VALVE MECHANISM Filed July 2, 1942 C52. 43 27 8 26 62524 ID INVENTOR J (LTTLQ SAD-am beU,

I WWW-1 M ATTO R N EY Patented Mar. 28, 1944.

T OFFICE DRAIN VALVE MECHANISM James A. Campbell, Oakland, Calif., assignor to The Westinghouse Air Brake Company. Wilmerding, Pa., a corporation of Pennsylvania Application July 2, 1942, Serial No. 449,527 8 Claims. (01. 3034s) 'This invention relates to drain valve equipments, and more particularly to an automatic drain valve mechanism for effecting periodic discharge of water accumulating in the main reser-' voirs of a locomotive.

In the operation of railway locomotives in regions of high altitudes, or under cold weather conditions generally, one problem which has been encountered for man years without satisfactory solution has been the need for means to expel condensed moisture from the main reservoirs before the water can be carried to the feed valve and other devices of the air brake system, where freezing of such condensate would interfere with operation of the brakes. A number of automaticdrain valve devices have been proposed for' draining both the main reservoirs and the after-cooler sometimes associated therewith, some of which are rendered operative upon each application of the brakes, and others of which are designed for intermittent operation by the usual pump governors. Although a measure of success has been achieved with certain of these devices, there still exists a need for a dependable inexpensive automatic mechanism operable at regular intervals with a low consumption of main reservoir air to provide proper'drainage of accumulated water from the system.

-A principal object of my invention is to provide an improved drain valve mechanism fulfilling the above requirements.

Another object of the invention is to provide a drain valve mechanism which is operative periodically at predetermined intervals to eject condensate from a main reservoir or the like, regardless of the frequency of applications of the brakes, or of the functionin of the pump governor.

Other objects and advantages of invention will appear in the following more detailed description, taken in connection with the accompanying drawing, in which the single figure is a diagrammatic sectional view of a drain valve mechanism constructed in accordance with the invention.

For the purpose of disclosing the invention, the equipment shown in the drawing is represented in elementary form, and includes a main reservoir I, which is adapted to be supplied with air under pressure by means of a suitable compressor, not shown, and which ha associated therewith a pressure actuated drain valve device 2 and a timing valve device 3. 'It will be understood that in actual practice the drain valve device and timingvalve' device may be associated with more than one'main reservoir; or with an after-cooler or'the like, depending upon the equipment carried by the locomotive.

The drain valve device 2 comprises a casing section 5 suitably secured to the bottom of the main reservoir I, a casing section 6 bolted to the casing section 5, and a flexible diaphragm I, which is clamped between the two casing sections in a canted position, forming on one side thereof a pressure chamber-8 and on the opposite side a chamber 9 communicating with a drainage tube I0. Formed in the casing section 5 is a condensate collection chamber I2 which communicates by way of a passage I3 with the interior of the main reservoir I. A bore I4 connects the chamber I2 with a valve chamber I5, also formed in the casing section and communicating by way of a bore I6 with the ejection chamber 9. A double valve element I8 disposed within the valve chamber I6 is engageable with a seat I9 for controlling communication between the chambers I2 and I5, or alternatively with the valve seat 20 for controlling communication between chambers I5 and 9. The double valve element I8 is supported through the medium of a fluted stem 23, slidably fitting the bore I4, and a similar stem 24- slidably mounted in the other bore I6, it being: noted that the valve element and stems are inclined in alignment with the axis of the canted. diaphragm 1. The fluted stem 24 operatively engages a follower member 25 which is attached to the diaphragm I, and which is subject to the force exerted by a coil spring 26 interposed between the follower element and an upper wall of the chamber 9. The spring 26 normally urges the diaphragm I downwardly and into engagement with a stop portion 21 of the casing. A coil spring 28 is interposed between the fluted stem 23 and an upper wall of the chamber I2 for urging the double valve element I8 downwardly into engagement with the seat 20, as shown in the drawing, in which position of the valve element communication is maintained between the chamber I5 and the chamber I2.

The timing valve device 3 comprises a timing reservoir 30 having a chamber 3I of predetermined volume, a casing section 32, which is bolted or otherwise secured to the reservoir, a casing section 33 similarly mounted on the casing section 32, and a strainer section 34 that may be mounted on the section'33. A suitable asket, indicated' at 35," may be interposed between the casing sections.

The strainer section 34 has a chamber 36 which communicates by way of-a pipe 31 with a main' reservoir I, and contains suitably mounted way 4| for controlling the rate of supply of air. H

to the timing chamber 3|.

Formed in the casing section 32 beneatn-the.a=

bore 33 is an enlarged bore 45, in which is slidably mounted a piston valve element 45 havinga;

valve portion 41 that is normally;mai ntaine.dini j engagement with a valve seat48"for"closing 'a' port 5!]. The piston valve element? cargri'es; .;a,

stem 49, which extends upwardly through the V bore 45 and into sliding engagement withthe bore 3.9, the length of the'stem beingsuchgastomaintain open the port 43 when the-valve :portionflc isseated, as shown in the drawing. It.;will.be

noted that thediameter. ofethe. valve:portion.-;4| r is considerably greater thanthat of-;the,stem 49.. The piston Valve element 45 is also provided-with. a restricted passage 5|, forming communication, between a chamber 52 at the lowerfaceof. the. piston valve element and the portion of. thebore 45 at the; u per side. "thereof, which; is. connected.

to ;the

atmosphere byway of apassage 53. It will be understood that the pistonvalveelement. 4B is thusdesigned for operation-with a quick. orsnapaction, in-response to an increase in,fluidi. pressure initially forcingihe. valve .portion-.4lsaway from its seat :and subsequently acting-on the lower surface of-the valve element exposed to. the. chamber 52, and that, the element can; be held-inits uppermost positionaby aclower pres sure-thanthat required tounseatitr In ;operation,. compressed zairr.--supplied in the usual v; manner, to the main reservoir, flows; through thepipe "31,. chamber ;36,,;pass age 39,. port .49; and passageway 4 to the timing; reservoir .chamber- 3|, and also .by -way, ofi;pipe .43-,tothe chamber 8 in the main valve device The 4 pressure of air inthe timing reservoirechamber 3| and .theldiaphragml chamber 8 is thus-;-gr,ad-:- ually increased-at a rate .determined by lthe size of the restrictedpassage of. the choke. plug interposed in=the passageway. When ,the pres sure of air acting against the diaphragm-1 of the. drain valve device has been thus increased=sufli ciently to overcome theaopposing forceexerted by the springs 25 and, the diaphragm.is;;force.d-

upwardly, therebymaising'therdoublewalve ele ment |8away from the lower valVeseat-IO-and into engagement with the uppervalve seat 19. As the double valve element |B thus traverses the distance 3 between the. two seats, the re1ati,vely 3 high pressure of air contained in the maintreservoir actsv against any accumulated-water, which may have collected-in the chamber l2 and connected chamber 5-by flow from the; reservoir I through the passage l3; andquickly;drives;out

valve devicewi1l:be rendered;operativezperiodical such water byway of .the chamber. 9 anddrainage1.-

tube IE1. This discharge of compressed ,air,,-from the main reservoirj ishof, course Quickly gtermia-g, nated-by engagement; ,of the doubleivalve ele ment l8 avithgthe upper seat ;|9,,s0,,that 10111315: ax small amount'of air isrequired for'the operatiom; Drainage of water from the chamber; 9 :is; f acili-; tated by reason of the inclined position ,-injwhich thediaphragm l is disposed;

Air under pressure is meanwhile. continuously;

supplied by way of passage 4| and the restricted passage 44 to timing chamber 3|, and when the pressure efiective on the surface of the valve portion 41 exposed to the passage 50 becomes great enough to overcome the weight of the piston valve element 46 and the opposing pressure of air acting on the stem 49, the element is forced upwardly. As the valve portion 41 is moved away from theseat 48, the pressure of-air in the timing chamber becomes effective over the entire area of the valve element exposed to the chamber 52 =whereupon the element is moved to its uppermost position with a snap action, the stem 49 being thereby operated to close the port 40.

r Further supply of air from the main reservoir to the timinggch'am-ber 3| is thus cut off, while air under" pressure is discharged therefrom at a controlledira-te by z'fiow through the restricted passage 5| in the piston valve element 46 and thence I throughthe atmospheric passage 53.

, When the pressure of airincthettimingchamber 3| and in theLdiaphrag'm chamberQ-fllicong nected; thereto. has. been. reduced sufficiently the, combined forces of .the ,two coil. springs -2fi-randr 28 of the drain valve device ,VareFthenQrendered, effective to shift the associated diaphragm. 1', follower member, 25 and doubleva-lve element. l8 to" the .position. in which they are illustrated inithe drawing, In traversing the distance. between.

.the-seat l9 andthe seatZU, the double valveiele "mentcl8 again efiectsaa quickilimited discharge--,

ofrwa'ter that has been. condensedlfrom the air; in the reservoir as .hereinbefore explained. Continuedflbw ofair under pressure from: thee timing chamber 3|., passageway 4| and chamber" 52 through thedpassages 5 I. and 53 finally results in"v reduction in the..p'ressure acting upwardiy on"; the piston valverelement 46. a a. value,les s..than a that required to. hold the element t in, the upper;

.most position, whereupon. that element is.; again 7 moved to its seatedposition.bythe-forceof grav-- 0 the invention. may be mounted onca lQOQl'flOiii-KZG;

in any convenient position,- with 'the'timing YHJY K? device spaced any desired distance away;;from

the drain valve device. It. will further-.beevident a that withzthe timing reservoirand associatedreleer ments properly proportionednwith relationytocther; pressure carried in th'e .mainareservoin, the;v drain ly and often enough to keep the reservoir su stantially dry'atv all times;. i

Having now described my invention; when: :1 claim. as.,new. .and. .desire' to secure v-by .Letters *1 Patentisz' e i 1; i In: an automatic :drainage rapparatusz for pe riodic'ally r discharging condensate from :an J air-Ev 1 3 storage 7 reservoir, in; combination; arvalve: device operativeyto eject;:condensate from'said reservoirl': lIL-IBSDOIISB;1705561331181 .8111 .zincreaseor-raadecreasee' in; pressure iofaair' ;in a ichamber; eaetimingzrresen voir. communicating .with r said. chamber; meani for: supplying ;-air.: undei: pressure ;to said: timingt: reservoir,; and waive lmeans mespcnsive :to a rpredetermined :iincrease in timingsreservoin pres-a sure '.to.;vent iaircfromsaid chamber. 1

2.,;In an; automatic :drainage; z-apparatussnforr 75.;periodically gdischarging 1condensate -from aan V ant-.2

storage reservoir, in combination, a valve device operative to eject condensate from said reservoir in response to either an increase or a decrease in pressure of air in a chamber, a timing reservoir communicating with said chamber and with said storage reservoir, means restricting said communication between said timing and storage reservoirs, and valve means responsive to gradual increase in timing reservoir pressure to a predetermined value for venting air from said chamber and said timing reservoir.

3. In an equipment of the class described, the combination with an air storage reservoir of a fluid pressure actuated drain valve device operative to effect discharge of water condensed in said reservoir, and timing valve mechanism remote from said reservoir and drain valve device, said timing valve mechanism comprising valve means controlling the supply and release of air under pressure to and from said drain valve device, and timing means for causing operation of said valve means at predetermined intervals.

4. A timing valve apparatus for controlling periodic operation of a fluid pressure actuated drain valve for an air storage reservoir, comprising a, timing reservoir, means providing communication through which air is supplied from the storage reservoir to said timing reservoir at a restricted rate, a snap acting valve element operative upon a predetermined increase in the pressure of air in said timing reservoir to vent air therefrom while cutting off said communication with the storage reservoir, said valve element being subsequently operative, when pressure of air in said timing reservoir has been reduced, for reestablishing communication thereto from said storage reservoir while stopping further venting of air, and means for communicating such variations in timing reservoir pressure to said drain valve device for effecting corresponding operation thereof.

5. A timing valve mechanism for controlling periodic operation of a fluid pressure actuated drain valve for an air storage reservoir, comprising a casing structure having a timing chamber, a communication formed in said casing structure through which air under pressure can be supplied from the storage reservoir to said timing chamber, air straining means and flow retarding means interposed in said communication, a reciprocating valve element slidably mounted in a bore in said casing for controlling commu-- nication from said timing reservoir to atmosphere, said valve element being constructed and arranged to control alternate increase and reduction in timing reservoir pressure, and means for communicating such periodic variations in pressure to said fluid pressure actuated drain valve device.

6. A timing valve mechanism for controlling periodic operation of a fluid pressure actuated drain valve for an air storage reservoir, comprising a casing structure having a timing chamber, a communication formed in said casing structure through which air under pressure can be supplied from the storage reservoir to said timing chamber, air straining means and flow retarding means interposed in said communication, a reciprocating valve element slidably mounted in a bore in said casing for controlling alternate increase and reduction in timing reservoir pressure, said piston valve element having a vent valve portion always subject to timing reservoir pressure, an enlarged surface surrounding said valve portion and arranged to be subjected to timing reservoir pressure only when said valve portion is unseated, and a stem portion for controlling the communication between said storage and timing reservoirs, said stem portion having a pressure area less than that of said valve portion subject to storage reservoir pressure in opposition to the timing reservoir pressure acting on said valve element, and means for communicating such periodic variations to said fluid pressure actuated drain valve device.

7. In a drain valve equipment of the class described, the combination with a reservoir adapted to be supplied with air under pressure, of a drain valve device having a Water accumulating chamber into which water can flow from said storage reservoir, a double valve in said chamber cooperable with either of two seats formed in said device, a movable abutment subject to variations in fluid pressure for moving said double valve from one seat to the other to efiect periodic quick discharge of Water from said accumulating chamber, and timing means operative by air under pressure from said storage reservoir for alternately increasing and reducing the fluid pressure acting on said movable abutment.

8. In a fluid pressure system including a receptacle for receiving fluid under pressure, in combination, a fluid pressure actuated drain valve device constructed and arranged to collect and efiect discharge of water condensed in said receptacle, said drain valve device being operative periodically upon alternate variations in the pressure of fluid in a chamber within a predetermined range, and fluid pressure responsive timing valve means controlling the supply and release of fluid under pressure to and from said chamber, said timing valve means being automatically operative upon increase in pressure in said chamber to a maximum beyond said predetermined range for initiating gradual venting of fluid therefrom, and upon resultant decrease in said pressure to a minimum beyond said predetermined range for initiating gradual supply of fluid under pressure to said chamber.

JAMES A. CAMPBELL.

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