US2024685A - Pressure retaining valve device - Google Patents

Description

17 Q Q ARMER 2,@24 @85 PRESSURE RETAINING VALVE DEVICE Fi led March 17, 1952 [III , I H a q N g 4 Q m i? L k g 5 E INVENTOR.

CLYDEC. FARMER BY ,g% 4% A TTORNE Y.

LOW PRESSURE Patented Dec. 17, 1935 UNITED STATES PATENT OFFICE PRESSURE RETAINING VALVE DEVICE Application March 17, 1932, Serial No. 599,374

4 Claims. (Cl. 303-79) This invention relates to a fluid pressure retaining valve device of the type employed with fluid pressure brake systems for retaining fluid pressure in the brake cylinder.

With the present standard so-called three position retaining valve, when the handle points vertically downward, the brake cylinder pressure is completely released in a predetermined time, for example about four seconds, after the triple valve moves to its release position. With the retaining valve handle in 45 angle position from the vertical, the brake cylinder pressure is permitted to reduce at a very slow rate and is prevented from reducing below twenty pounds by the closure of a spring loaded valve. With the retaining valve handle in horizontal position, the brake cylinder pressure is permitted to reduce at a restricted but somewhat faster rate than was just described for the 45 angle position and the brake cylinder pressure is prevented from reducing below ten pounds by the closure of a spring loaded valve.

The closing value just given for the retaining positions is necessary on trains of considerable length on descending grades of considerable percentage to avoid the brake cylinders becoming empty within that period of time which is required for the recharge of the auxiliary reservoirs. Should the brake cylinder be permitted to become empty during a recharging period, the succeeding brake pipe reduction must exceed five pounds before any retarding force is again developed. Where the retaining valve closes the exhaust and holds twenty or ten pounds in the brake cylinder, the lightest succeeding brake pipe reduction which will cause the triple valves to move to their application positions will immediately produce an increased retarding force on the cars.

With the retaining valve turned to one of its retaining positions, the brake cylinder pressure is permitted to reduce rather slowly to the closing value of the retaining Valve and this amount of cylinder pressure and retarding iorce then becomes permanently active to prevent excessive acceleration of the train while the auxiliary reservoirs are becoming fully recharged.

Under retaining valve operation as described, it will be obvious that, when a train on which the retaining valves are turned to retaining position reaches a level track grade or an adverse grade, the train will be stalled unless the retaining valves are turned down. Again, as is quite common on a considerable amount of main line track, a train must move over a generally descending grade of small degree, say one and one-half per cent or less. The closing value of the retaining valve in even its ten pound position provides more retarding force within the train than that with which it can be kept in motion, the result of 5 which is that either a portion of the retaining valves must be left in their direct exhaust position or an attempt made to so manipulate the brakes in the train as to secure safe control without the use of retaining valves. Both of these 10 latter methods are practiced but both are objectionable.

Where only a portion of the retaining valves are employed, all of the brake work in controlling the train will be concentrated on the wheels of the 15 cars on which the retaining valves are in retaining position, thus creating an undesirable amount of heat in the wheels of such cars. Again, when a train so operated must be moved for a distance over level or even adverse grade, as is quite 20 common, trainm-en must go over the train and turn all retaining valves to direct release position and then, when the train is again entering the descending grade, they must go back over the train and again turn the needed number of re- 25 taining valves to retaining position.

Another objectionable feature of such an arrangement for controlling train speed is that the consumption of air by the cars having retaining valves turned down is as great as though the 30,

brakes on these cars were efiective, whereas they normally in no way contribute to the control of the train speed.

Where trains and particularly long trains are controlled over such low and undulating grades, 35 as just described, and without the use of retaining valves, the time between brake applications is usually insufiicient to accomplish the recharge of other than the brakes on the front portion of the train and, therefore, as with only a portion 40 of the retainers turned up, the brake work is concentrated on the front portion of the train, and in addition to this, the consumption of air required for controlling the train greatly exceeds the amount needed for control when a portion of 45 the retaining valves are employed, as previously described.

The principal object of my invention is to provide a retaining valve device having means for overcoming the above difliculties and for this 50 purpose, the retaining valve device is provided with a fourth position, in which fluid under pressure is released from the brake cylinder at a predetermined slow rate which, to accomplish an increase in flexibility for the control of trains 55 on the light grades, is at a somewhat faster rate than provided for in the ten pound retaining position.

In addition, this fourth position of the retaining valve will not have a closing value and consequently in some given period, say sixty seconds, after release movement of the triple valve, the brake cylinder pressure will have reduced from sixty tofive pounds, with which latter pressure the retarding force of the brake becomes substantially nil. Having retainers provided with the fourth position and all of them in a train placed in this position, sixty seconds time will be available for recharging the auxiliary reservoirs of the cars before the brake pistons can recede in their cylinders, and, therefore, if the brakes are then reapplied all of the brakes in the train will immediately develop effective retarding force.

With the retaining valves of this type and used as described, if the train is approaching a level or adverse section of the generally descending grade, a brake release is initiated in time, all brake cylinder pressure will be exhausted, and consequently the train will be as free to move over the level or adverse grade section as though the retaining valves were in their direct release position.

In the accompanying drawing; Fig. 1 is a central sectional view of a pressure retaining valve device, embodying my invention, showing the controlling valve in the quick release position; and Fig. 2 an elevational view of the retaining valve device, partly in section, to show the controlling valve in the slow release position.

As shown in the drawing, the pressure retaining valve device may comprise a casing I in which is mounted a pair of spring loaded pressure retaining valves 2 and 3, and a controlling plug valve 4. The valve 2 is provided with a stem 5 which is guided in a bore of a cap nut 6, having screw-threaded engagement in the casing and the valve 3 is provided with a stem 1 which is guided in a bore of a cap nut 8, having screw-threaded engagement in .the casing A coil spring 9 mounted in chamber l0 and surrounding the stem 5, is interposed between a wall of the nut 6 and a collar carried by the stem 5 to hold the valve 2 seated against a predetermined pressure, and a coil spring l2 mounted in chamber l3 and surrounding the stem 1, is interposed between a wall of the nut 8 and a collar l4 carried by the stem 1, to hold the valve 3 seated against a predetermined pressure.

The valve 2 controls communication from a passage l5 leading to the seat of plug valve 4, to chamber H], and valve 3 controls communication from a passage IE to chamber l3, the passage I6 communicating with a passage leading to the seat of plug valve 4.

Chamber I0 communicates with a passage l8 leading to passage through a restricted port l9 in a choke plug 20 which is mounted in passage l8, and chamber l3 communicates with the atmosphere through a restricted port 2| in a choke plug 22.

The plug valve 4 is provided with an operating handle 23 and has four operating positions as follows: quick release, high pressure, low pressure, and slow release.

In the quick release position, as shown in Fig. 1, the plug valve 4 is so positioned that a through port 24 therein connects a chamber 25,

open to pipe 26 (which pipe is connected to the usual brake cylinder exhaust of the usual triple valve device) (not shown), to an atmospheric exhaust port 21, so that with the plug. valve 4 in this position, fluid released from the brake cylinder, upon movement of the triple valve device to release position, is vented directly to the atmosphere at a rapid rate, say such that the brake cylinder pressure will be completely released in about four seconds.

When the plug valve 4 is turned to the high pressure position, the port 24 connects chamber 25 with passage i5, so that fluid released from the brake cylinder first acts to unseat the valve 2 against the pressure of spring 9 and then flows from chamber I0 through restricted port I9, and passages l8 and I! to passage l6. The valve 3 is then unseated by fluid pressure against the pressure of spring I2 and fluid under pressure flows to chamber l3 and thence to the atmosphere through restricted port 2|. When the brake cylinder pressure has been reduced to a predetermined degree, say twenty pounds, the valves 2 and 3 will close, thus retaining a pressure of twenty pounds in the brake cylinder.

When the plug valve 4 is turned to the low pressure position, the port 24 connects chamber 25 with passage so that fluid released from the brake cylinder only has to flow past the valve 3 tothe atmosphere. When the brake cylinder pressure has been reduced to a predetermined low degree, such as ten pounds, the valve 3 will seat and cut off the further release of fluid from the brake cylinder.

As so far described, the positions and operation of the retaining valve device are the same as the retaining valve devices now employed in service, but according to my invention, a fourth position of the plug valve 4 is added in which fluid may be released from the brake cylinder directly to the atmosphere at a slow rate. In this position, as shown in Fig. 2, a cavity 33, cut in the valve 4 and opening into the passage 24, provides communication in this fourth position from chamber 25 to port 24. In this position, communication is established from port 24 to atmospheric exhaust port 21 by way of a restricted port 3|, the port 3| opening into port 24 and leading to a port 32 of greater area which opens at the seat of the plug valve 4.

The flow area of restricted port 3| is such that fluid will be released from the brake cylinder at a somewhat greater rate than fluid is released from the brake cylinder in the low pressure position, but yet at a sufficiently slow rate to permit the auxiliary reservoir on the cars throughout the train to be recharged with the triple valves in release position and at the same time retain suflicient pressure in the brake cylinder to prevent undue acceleration of the speed of the train.

The fourth or slow release position is defined by the engagement of the handle 23 with a stop pin 33, which is secured in the casing at the proper position.

In order to convert a retaining valve device of the existing type to the improved type, a stop lug on the existing retaining valve device which defines the low pressure position is cut off and the casing is drilled to provide a bore into which the pin 33 is driven.

The plug valve of the existing type of retaining valve device is machined to provide the cavity 30 and the restricted port 3 I, so positioned that in the fourth position, communication will be established from the chamber 25 to the exhaust port 21.

While one illustrative embodiment of the invention has been described in detail, it is not my intention to limit its scope to that embodiment or otherwise than by the terms of the appended claims.

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

1. A pressure retaining valve device comprising a loaded pressure retaining valve device and a manually operable plug valve having a through port, through which fluid flows from a fluid pressure inlet to the atmosphere at a rapid rate in one position of the valve, and through which fluid flows from the inlet past the loaded pressure retaining valve to the atmosphere in another position of the valve, said valve having a restricted port communicating with said through port, and with the atmosphere in a third position of the valve, and said through port having an extended cavity which communicates with the fluid pressure inlet in said third position, whereby communication is established in said third position from the fluid pressure inlet, through a restricted port, to the atmosphere.

2. A pressure retaining valve device comprising a loaded pressure retaining valve and a manually operable plug valve having a port embodied therein for establishing a communication from a fluid inlet in said valve device to a fluid outlet in said valve device, through which communication fluid may flow at a relatively unrestricted rate when said plug valve is in one position, said plug valve having also embodied therein a restricted port for restricting the rate of flow of fluid from said fluid inlet to the said fluid outlet below said relatively unrestricted rate when said plug valve is in another position, said valve device being provided with a restricted port for restricting the rate of flow of fluid from said fluid inlet to a second fluid outlet through said pressure retaining valve below the restricted rate effected by the restricted port in said plug valve, when said plug valve is further operated to an- 5 other position.

3. A pressure retaining valve device comprising a casing having a fluid inlet and two different fluid outlets, a loaded pressure retaining valve controlling a communication for the flow of fluid from the said fluid inlet to one of said fluid outlets, and a manually operable plug valve having a port therein adapted in one position of said plug valve to establish said communication, the said plug valve having a port adapted in a second position of the plug valve to establish a com munication for the flow of fluid from said fluid inlet to the other of said outlets, and having also a restricted port adapted in a third position of said plug valve to establish a. communication through which fluid flows from said fluid inlet to said other fluid outlet at a lesser rate than in the said second position of said plug valve.

4. A pressure retaining valve device comprising a casing having a fluid inlet and two different I fluid outlets, a pair of pressure retaining valves loaded at difierent values, respectively, and controlling two different communications, respectively, between said fluid inlet and one of said fluid outlets, and a manually operable plug valve having a port adapted in a first and a second position, respectively, of said plug valve to establish said two communications, said plug valve having a port adapted in a third' position of said plug valve to establish a communication through which fluid flows at a certain rate from said fluid inlet to the other of said outlets, and having also a restricted port adapted in a fourth position of said plug valve to establish a communication through which fluid flows from said fluid inlet to 40 said other fluid outlet at a slower rate than said certain rate.

CLYDE C. FARMER.

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