US2320445A - Valve mechanism - Google Patents

Description

June 1, 1943. E, MARTIN VALVE MECHANISM Filed Nov. 28, 1941 2 SheetsSheet l June 1, 1943. M N 2,320,445

VALVE MECHANISM Filed Nov. 28, 1941 I 2 Sheets-Sheet 2 Z J/ 74: J/ 74 r 54.) fZaZ INVENTOR flame/V41 ATTORNEY Patented June 1, 1943 VALVE MECHANISM Eugene Martin, Erie, Pa., asslgnor to The Standard Stoker Company. Incorporated, a corporation of Delaware 7 Application November 28, 1941, Serial No. 420,775

Claims.

automatically effect reversal of a reversible pressure fluid operated engine when the engine stalls due to an overload; that will effect continued reverse operation of said engine for a predetermined period; and that will automatically effect forward running of the engine upon the expiration of said predetermined period.

More specifically it is an object of the invention to provide an operating and reverse valve for a stoker engine which will automatically effect reversal of the stoker engine for a predetermined period when the stoker conveyor stalls and automatically restore the stoker engine to forward running operation upon the expiration of the said predetermined period.

It is also a further general object of the invention to provide a valve mechanism as above dey scribed, that is positive and reliable in its action, consists of relatively few, simply constructed parts, and that can be manufactured at comparatively small cost.

With the above and other objects in view, the invention consists in the improved construction, combination and relative arrangement of I the several parts as hereinafter more fully described, claimed and illustrated in the accompanying drawings, and wherein Fig. 1 is a longitudinal vertical section through the rear portion of a locomotive with a stoker, and a pressure fluid operated engine and valve mechanism for operating the stoker, applied to the locomotive, a part of the stoker being broken away;

Fig. 2 is a central vertical section through the novel valve mechanism, the valve being shown in position for operating the stoker conveyor in forward direction;

Fig. 3 is a central vertical section through the novel valve mechanism, the valve being shown in position for operating the stoker'conveyor in retaken on the line .l-i of 2.

The invention is illustrated in the drawings and will be described as applied to the stoker engine of a locomotive, but it will be apparent that the novel valve mechanism is equally adaptable to engines for operating other devices and appliances.

Referring specifically to Fig. 1, the locomotive is indicated by the letter L and comprises a frame Ill upon which the boiler backhead l l is supported by means of an expansion plate II. A cab deck l3 extends rearwardly from the backhead ii and is supported at its rearward end on the frame I0 by expansion plate l4.

The stoker is shown at S and includes a fuel discharge conduit l5 supported at its upper end from the backhead H by a bracket l6 and at its lower end by a bracket ll. The lower end of the discharge conduit i5 is flexibly connected with and supports the forward end of another conduit l8 leading forwardly from the tender (not shown). A conveyor screw, such as l9, extends through the conduits l5 and II and conveys fuel therethrough for delivery into a flrebox contained within the boiler. The conveyor screw it is operated by means of gearing (not shown) driven by shafting 20 having an operative connection with the stoker drive engine E.

The engine E is of the mul-ti-eylinder, double acting type and utilizes steam or other pressure fluid as an operating medium therefor. The engine is rigidly secured in any suitable manner to the locomotive frame Ill. The admission of steam or other pressure fluid to the driving engine E and the exhausting of steam therefrom are controlled by a reversing valve V having an inextensible rod 2| which extends upwardly through the cab deck I 3 and terminates in the handle 22 by which the valve V may be manually manipulated.

Steam from the locomotive boiler is conducted to the valve V by means of an intake pipe 23 while the steam exhausted by the engine E passes through the valve V and thence through exhaust pipe 24. During normal forward running operation of the stoker, the valve V conducts steam from the intake pipe 23 to the pipe 25, the latter having a connection with the steam chest 26 of the engine. Steam exhausted from the engine passes through the pipe 21 into the valve V and thence to exhaust pipe 24.

Reversal of the stoker engine E, when the stoker conveyor stalls, and resumption of forward operation after a predetermined interval of time is accomplished automatically in the manner hereinafter described, and manual reversal is accomplished by raising the rod 2|. During such reverse operation the valve V admits steam from pipe 23 to pipe 21, the steam exhausting through pipe 25, valve V and thence through pipe 24.

Referring now to Figs. 2 to 5, inclusive, illustrating the detailed construction of the control valve V, it will be seen that it comprises a body member 28 having axially alined upper and lower bores 29 and 38, respectively, and'bore 3| laterally disposed with respect to lower bore 38. Within the cylindrical bore 29 there is mounted a movable hollow valve element 32 arranged for movement within the body 28 by means ofa stem 33' which has an operative pivotal connection as at 34 with the rod 2|. The upper'end of the valve body 28 is covered by a cap 35 secured to the valve body by studs 36, the cap 35 having a stuffing box 31 through which the stem 33 passes. The movable valve element 32 is in the form of a spool having an upper enlarged end 38 and a lower enlarged end 39. In each enlarged end 38, 39 of 33 is provided with a shoulder 43 seating against a central boss 44 which is formed with the valve element 32 and connected to the cylindrical walls thereof by ribs 45. The stem 33 passes through the central boss 44 and its lower end is engaged by a nut 46 drawn tightly against the under side of the boss 44 to form a secure connection between the stem 33 and the movable valve element 32.

A stem 41, threaded in the nut 46, extends downwardly fromand in axial alinement with the stem 33, through the wall 48 into the lower bore 38. The open lower end of the bore 30 is provided with a cap nut 48 threaded into the body member 28. The cap nut 49 is provided with a passage 50 in which is disposed a ball check valve 5| effecting one way flow communication from atmosphere into the bore 38. The lower end of the stem 41 carries a piston 52 adapted for slidable movement in the bore 30. A compression spring 53 encircles the stem 41, one end thereof being received in an annular groove 54 in the wall 48 and the other end thereof being received in an annular groove 55 in the piston 52.

In the bore 3| is mounted a movable hollow spool-shaped valve element 56, having an upper enlarged end 51 and a lower enlarged end 58. A cap nut 59 is threaded into the body member 28 in the lower portion of the bore 3| forming a seat for the valve element 56. A plug 68 threaded in the cap nut 59 forms a seat for one end of the compression spring 6|, the other end thereof contacting the transverse web 62 within the hollow valve element 56 urging the latter to the position shown in Fig. 2. The pressure of the spring 6| can be adjusted by threading the plug farther in or out of the cap nut 59, and can be secured in adjusted position by drawing the lock nut 92 tightly up against the cap nut 59. The upper end of the enlargement 51 of the hollow valve element 56 is formed with a seat 63 arranged to receive a disc valve 64 which, in the absence of any substantial pressure in the passage 65 connecting bore 3| with port 66, is maintained in an open position by means of a spring 61 encircling the valve stem 68.

valve body 28 is provided with a laterally opening exhaust passage 69 threaded to receive the exhaust pipe 24. A drain passage 18 in the valve body 28 establishes communication between the exhaust passage 69 and the lowermost point of a passag 1| extending vertically along a side of the valve body. Adjacent the lower portion of the passage 1|, the valve body is threaded to receive pipe 21 which, during normal stoker operation, conducts exhaust steam from the engine E to the exhaust pipe 24 through the valve V. At the upper portion of the valve body 28 the passage 1| opens inwardly, as at 12, into the bore 29 for conducting the exhaust steam through the valve element 32 during normal stoker operation.

The steam intake pipe 23 is threaded into a boss 13 and admits steam between the enlarged ends 38, 39 of the movable valve element 32 for selective distribution into either of the pipes 25 or 21. As illustrated in Fig. 2, the normal or forward operation of the stoker engine E is attained by moving the valve element 32 to a position in which its lower end 39 rests upon the seat 42. In this position steam passing from the intake 23 enters. the bore 29 between the enlarged ends 38, 39 of the valve element 32 and then passes through port 66-into the-pipe 25 for admission to the steamchest 26. Under such operating conditions, the pressure of the steam entering passage 65 closes the disc valve 64 against the force of the spring 61, and the compressive strength of the spring 6| is such as to retain the valve element 56 in its upper closed position, as shown in Fig. 2. In the absence of any substantial pressure in port 66, the disc valve is maintained in an open position by means of the spring 61 so that any accumulated condensate in pipes 23, 25 will 'flow through the hollow valve element 56 and the drain passage 14 before operation of the stoker engine is started.

Occasionally the stoker will stall due to a fuel jam or extraneous material which may have found its way into the conveyor. In such instances it has been the practice to'manually operate the reverse valve to reverse the operation of the engine for a few revolutions and then return it to normal operating position. If the jam has not become loosened or extraneous matter dislodged or carried through by the conveyor, the operation of reversing the engine and returning it to forward operation is repeated. My invention, as hereinafter described in detail, provides means whereby the engine is automatically thrown into reverse for a predetermined period when the stoker stalls and then automatically returned to forward running position.

When the stoker engine E stalls due to an overload, steam pressure builds back in the pipe 25 and port 66 and when the pressure has built up to an extent sufficient to move the valve element 56 from the position shown in Fig. 2 to the position shown in Fig. 3, pressure fluid will flow through the passage 65 into the bore 3| and then through the passage 15, connecting the upper end of the bore 3| with the lower end of bore 89,

into the bore 38 beneath the piston 52.

The spring 53 is of a strength, preferably, to

. just overcome friction between the piston 52 and Below the seat 39 for the valve element 32, the

the walls of the bore 36; the valve element 32 and the walls of the bore 29; and the friction of the stufling box 31, whereby under normal operating conditions movement of the piston 52 and valve element 32 to the position shown in Fig. 2 will be facilitated. Since the spring 53 is only of sufficient strength to overcome friction, pressure fluid entering bore 30 beneath piston 52 raises the latter and also the valve element 32 to the position shown in Fig. 3. In this latter position of the valve element 32, communication is effected betweenthe intake pipe 23 and the port 12, whereby pressure fluid flows through passage H into pipe 21 to the engine E, reversing its operation. In this position of the valve element 32 also, the port 66 communicates through exhaust passage 69 with the exhaust pipe 24, whereupon the spring 6| forces the valve element 55 upwardly to the position shown in Fig. 2, closing oi? the upper end of passage and trapping pressure fluid in bore beneath the piston 52. v

In this latter position of the valve element 56 communication is provided between a port 'ili and bleed valve 11 through the enlarged end 51 and 58 of valve element 56, permitting thetrapped pressure fluid to escape slowly. The escape of pressure fluid can be regulated by a threaded nut I8 to retain the piston 52 and valve element 32 in its upper position for apredetermined period and thereby permitting reverse operation of the stoker engine E for a predetermined period. When the pressure beneath the piston 52 has been, sufliciently reduced, the valve element 32 will return first to a neutral position, cutting oif the flow of pressure fluid from intake pipe 23 to both pipes 25 and 21, and then to its normal forward tween intak pipe 23 and pipe 25.

If it is desired to manually move the valve element 32 to neutral position, the operator grasps handle 22, turn and raises it and engages keeper I9 in notch 8|], and similarly engages keeper 19 in notch 8| to move the valve element 32 into position for reversing the stoker engine. The rod 2| slides freely in handle 22 durin automatic operation of the valve.

For purpose of illustration, let it be assumed that valve 82 in pressure fluid intake line 23 (see Fig. 1), is set to admit pressure fluid at 25 pounds from the high pressure side of the line and let it be further assumed that the stoker engine E normally operates the stoker at 25 pounds pressure. The pressure of spring BI is such that under normal forward running operation of the stoker engine, the valve 56 closes .the passage 65, as shown in Fig. 2.

Now let it be assumed that a hard lump of coal or other obstruction has caused the stoker to stall. Pressure will build up in the line 25 causing the valve 56 to move downwardly to the position shown in Fig. 3 against the pressure of spring 6|. In order to avoid downward movement of valve 56, and consequent reversal of the stoker engine, each time the stoker engine labors, the

pressure of the spring BI is adjusted to resist opening or downward movement of valve 56 until the pressure in line 25 has built up to about 40 pounds.

When the pressure in line 25 has built up to 40 pounds, and valve 56 opens, pressure fluid passes through passage 15 into bore 30 beneath the piston 52, effecting upward movement of piston 52 and consequently upward movement of valve element 32 to the position shown in Fig. 3. In the latter position of valve element 32, line 25 communicates with exhaust pipe 24 through the valve V, the drop in pressure in passa 55 causes spring 6| to move valve 56 upward, closing oil passage 15 and trapping pressure fluid in bore 30 beneath piston 52 thereby retaining valve element 32 in its upper position. In its upper position, valve element 32 provides communication between intake pipe 23 and port 12, whereby pressure fluid passes to the engine E through pipe .27 effecting reverse operation of the stoker engine and stoker.

The trapped pressure'fluid beneath piston 52 passes through port 16 and escapes through bleed valve 11 to atmosphere. The bleed valve 11 may be regulated to control escape ofpressure fluid so that valve element 32 may be retaine in its upper or reverse operating position a predetermined period of time, preferably a length of time sufiicient to permit several revolutions of the stoker conveyor screw [9. When the trapped pressure fluid has escaped, piston 52 and valve element 32 descend to the position shown in Fig. 2, again operating the stoker in normal forward direction. v

I claim:

1. A control valve for a pressure fluid operate-l reversible engine, comprising a body member having a valve chamber and a piston chamber, said valve chamber having a pressure fluid intake port and a pair of pressure fluid discharge ports,, a movable valve element in said valve chamber providing communication between said intake port and either of said discharge ports, a piston in said piston chamber operatively connected with said movable valve element, means providing a passage from one of said discharge ports to said piston chamber, valve means for opening and closing said passage, yieldable means normally retaining said valve means in a position closing said passage, and means providing a restricted. vent from said piston chamber to atmosphere when said valve means is in a position closing said passage.

2. A control valve for a pressure fluid operated reversible engine, comprising a body member having a valve chamber and a piston chamber, said valve chamber having a pressure fluid intake port and a pair of pressure fluid discharge ports, a movable valve element in said valve chamber providing communication between said intake port and either of said discharge ports, a piston in said piston chamber operatively connected with said movable valve element, means providing a passage from one of said discharge ports to said piston chamber, valve means in said passage responsive to the pressure of the fluid in said last named discharge port for admitting pressure fluid to said piston chamber and for closing said passage to trap pressure fluid in said piston chamber, and slow release means for venting pressure fluid from said piston chamber when said valve means is in a position closing said passage.

3. A control valve for a pressure fluid operated reversible engine engine comprising a body member having a valve chamber and a piston chamber, said valve chamber having a pressure fluid intake port and a pair of pressure fluid discharge ports, a movable valve element in said valve chamber normally providing communication between said intake port and one of said discharge ports, means forming a passage providing communication between said last named discharge port and said piston chamber, a piston in said piston chamber operatively connected with said valve element, and valve means normally closing said passage, said valve means being responsive to a pressure above the normal pressure in said last named port to admit pressure fluid to said piston chamber to move said valve element through said piston to a position providing communication between said intake port and the other of said discharge ports and venting said first named discharge port, said valve means besaid first named discharge port to close said pas- I sage and trap pressure fluid in said: piston chamber to retain said valve element inj-its last named position, and 'slow release mechanism associated with said piston chamber for releasing the trapped pressure fluid, said valve element being arranged to return to its normal position upon release of the trapped pressfire fluid.

4. A control valve for a pressure fluid operated reversible engine comprising a body member having an upper chamber, a lower chamber, a laterally disposed chamber and a passage providing communication between said lateral and lower chambers, said upper chamber having a pressure fluid intake port and a pair of discharge ports, a movable valve element in said upper chamber, a piston in said lower chamber operatively connected with said movable valve element for moving the latter to establish communication between said intake port and either of said discharge 01' said discharge ports, and venting said first named discharge port, said valve means being responsive to venting of said first named discharge port to'close said passage trapping pressure fluid in said piston chamber to retain said movable valve element in position establishing communication between said intake port and said second named discharge port, and pressure fluid release mechanism associated with said piston chamber for venting pressure fluid, said valve element being responsive to venting of said trapped pressure fluid and returning to position establishing communication between said intake port and said first named discharge port.

5. The combination with a stoker having fuel conveying means and a pressure fluid operated reversible engine for operating said conveying means, of valve mechanism including a movable valve element normally admitting pressure fluid to said engine for operating said conveying means in a forward direction, and including means responsive to an overloadvon said engine when said conveying means stalls for automatically moving said movable valve element to a position admitting pressure fluid to said engine for operating said conveying means in reverse direction, said last named means including slow release means providing for return of said vlave element to its original position. v

EUGENE MARTIN.

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