US2261827A - Valve - Google Patents

Description

NOV. 4, 1941. w BROWN ETAL 2,261,827

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I AIR I |lr| SUPPLY I H 'INVENTOR. WILLIAM J. BROWN "w, EVAN A.EDWARD5 ATTORNEY Patented Nov. 4, 1941 v 2.26m VALVE William J. Brown and Evan A. Edwards, Rochester, N. Y., asslgnors to Taylor Instrument Gom-- panies, Rochester, Y., a corporation of New York Application July 24, 1940, Serial No. 347.160

lclalm.

This invention relates to valves and particularly to relay air valves. 1

In certain pneumatically-operated regulating systems, it is customary to employ a sensitive baflie and nozzle type of valve actuated in response to changes in a condition to be regulated,

which ba'file and nozzle operate a relay air valve to control the application of compressed air or other fluid for operating means to control the application of a regulating medium. The bafie and nozzle valve and the relay air valve have been separate structures with' an air conduit interconnecting them.

The present invention relates to a simple, inexpensive construction incorporating both valves in a single unit, thereby facilitating the assembly and installation thereof.

The various features and advantages of the invention will appear' from the detailed description and claim when taken with the drawing in which Fig. l is a vertical section showing the valve unitin its normal or open position together with its connection to a diaphragm motor valve; Fig. 2 is a similarview illustrating the valve unit in its closed position; and Fig. 3 is an enlarged view of a modified form of nozzle closure.

Referring to the drawing of the unitary valve of the present invention, the numeral 5 designates an elongated metal block which may be of cylindrical, rectangular or'other convenient shape. block has extending therethrough, a longitudinal bore 6, the respective end portions '5 and 8 of which are enlarged and the wall of each enlarged bore portion is internally threaded. The block has three lateral ports or passages 9, l and H extending through of to communicate with the bore 6. It will be noted that each passage has an extension or counterbore into the opposite wall of the bore as indicated at to, We and lie, for a purpose to be described. The port 9 may bean inlet port which communicates with a source of pressure fluid, such as compressed air. The port 50 is an outlet port which may communicate with the diaphragm top ,of a pneumatically operated valve V, while the port ii exhausts to the atmosphere. A generally cylindrical plunger l2 of a length approximately that of the bore proper is mounted in the bore, the major portion of the plungerbeing spaced from the wall of the bore about .0004

or an inch to make a close fit therewith, generally defined as a close running fit. The plunger at its intermediate portion is provided with a peripheral channel l3 of a width just great enough to span simultaneously either the the side wall thereports 9 and H! or I and H. plunger is provided with the peripheral grooves It and I5 adjacent the respective sides of the channel I 3 and so spaced therefrom as to afford communication with the ports 9 or tively in the several positions of the-plunger. The upper portion is of the plunger is of reduced diameter so that it can be inserted into a helical spring II, which spring is of a diameter to have a portion thereof received in the space between the reduced end portion of the plunger and the bore proper- The projecting end portion of the spring I! is received in a recess ill in a cap I!) which has external threads to engage the internal threads in the wall at the enlarged upper portion 1' of the bore. A perforation 20 through the cap communicates with the recess 18 so that back pressure will not develop against the upper end of the plunger.

The lower end portion 8 of the bore is closed by a brass disc 2!, the center of which is perforated and upset to jecting nozzle 24. The marginof the disc is mounted to make air-tight engagement with the wall of the body and for this purpose the body is provided with a shoulder 25 against which the margin of the disc engages. A vided with an externally threaded flange 28, has threaded engagement with the internal threads in the wall of the lower enlarged portion 8 of the bore. The free end of the flange 28 on the cap, engages the margin of the disc and forces it so snugly into engagement with the shoulder 25 on the body that the joint between'these parts is sealed against air leakage. The flange on the cap also defines a recess which communicates with the atmosphere through a bore 29 in the cap. This bore is of such diameter as to loosely fit the stem 30 of a movable valve element which includes a circular head 3i integral with, and

having its principal plane perpendicular to the axis of the stem. The surface of the head 3! adjacent the nozzle 26 has secured thereto, a disc of flexible material 32 preferably possessing the characteristics of synthetic rubber, now commonly sold under the name of Neoprene. This disc is conveniently secured to the head by means of an annular washer 33 having a plurality of ears 3 This washer engages the exposed margin of the-disc while the ears 3d are bent over the lower surface of the head. The bent over ears thus retain the .disc on the head and, in addition, insure that the head is always spaced from the cap it.

The cap 2? also clamps a bracket 35 against In addition, the

l I respec provide a downwardly procap 21, pro-' the lower surface oi the body 5. This bracket has a downwardly extending lug 36 serving as a fulcrum for the right-hand end of a lever 31 which extends in position to elevate the stem 30, when the left-hand end of the lever is raised. A leaf spring 38 holds the lever in contact with the free end of the lug 36. It will be understood that the bracket 35 can also be so positioned on the body 5 that the lug 36 will occupy the position shown in dotted lines. In this position, the stem 30 will be raised when the left end of the lever (shown in dotted lines) is lowered. The left end of the lever 31 may be raised and lowered by any suitable means (not shown), such as temperature, pressure or other conditions responsive means, or suitable time-actuated means.

In the operation of the present combined valve unit, a source of compressed air or like operating fluid is continuously supplied to the inlet port 9 of the unit. Since there is a clearance of .0004 of an inch between the plunger and the inner wall of the bore, there is a small continuous leakage of air past each end of the plunger. This valve unit is designed to be used in a system in which suitable actuating mechanism such as lever 31, controls the respective raising and lowering of the valve stem. When in the course of the operation of the system, the stem 30 is permitted to move the synthetic rubber disc 32 away from the nozzle 24 by gravity (Fig.1), the air pressure about the lower end of the plunger will be reduced and the coil spring l'l will restore the plunger to a position in which the exhaust port II is closed while the inlet port 9 and the outlet port [0 to the diaphragm motor of the valve V are placed in communication. Compressed air is thus supplied to this motor causing it to depress the stem of the diaphragm valve V.

When the stem 30 is raised (Fig. 2) until the synthetic rubber disc 32 reduces or completely prevents the escape of compressed air through the nozzle 24, the pressure in the bore 6 will build up about the lower end of the plunger l2, causing this plunger to be elevated against the action of the helical spring I! until the outlet port In and exhaust port II are in communication. This permits the diaphragm motor of the pneumatically operated valve to exhaust so that its spring S raises its valve stem.

It will be appreciated that in a valve or this type the plunger should be eflectively floating in air. In other words, there normally should be no unbalanced air pressures against any part of the plunger, except when the nozzle 24 is closed or partially closed. To this end the small grooves I4 and I5 and the counter bores 9a and Ha have been provided. It will be understood that these grooves tend to equalize the air pressures about the periphery of the plunger and the .pressure of the air in the counter bores 90. and

lla'equalizes or balances the opposing pressures due to the area of the ports 9 and I l. Thus the plunger eflectively floats in air.

In the slightly modified form of the invention illustrated in Fig. 3, the Neoprene disc 32 in the upper surface of the head 3| has been replaced by a tapered needle 40 attached to saidhead, which needle serves to control the flow of air through the nozzle 24. It should be understood that this form of the invention functions in the manner as that already described.

We claim:

In a valve unit, a body having a bore extending therethrough, said body also having an inlet port, an outlet port and an exhaust port communicating with said bore in the order named, said ports being continued as counterbores into the body at the opposite wall of said bore, a plunger making a close running fit with the wall of the bore whereby air will slowly leak past said plunger, said plunger being of a length to have each end extend beyond said ports and having a peripheral channel of a width to span either said inlet port and said outlet port or said outlet port and said exhaust port in the respective positions of adjustment, said plunger also having peripheral grooves respectively communicating with said inlet port and with said exhaust port in the respective positions of adjustment of said plunger, one end of said bore being closed by a disc in airtight relation with the wall of said bore, said disc having an opening therethrough, a spring tending to move said plunger toward said disc, a movable valve element having a part operable to close said opening whereby air pressure will build up about the adjacent end oisaid plunger, and means for moving said element toward said disc.

J. BROWN.'

EVAN A. EDWARDS.

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