US2574377A - Quick-release valve - Google Patents

Description

1951 T. R. COGGESHALL 2,574,377

QUICK RELEASE VALVE Filed NOV. 29, 1943 2 SHEETSSHEET 1 Fig. I.

Inventor: T he! lwel I R. Cogges ha! I,

His Attor'heg.

Nov. 6, 1951 T. R. COGGESHALL 2,574,377

QUICK RELEASE VALVE Filed Nov. 29, 1943 2 SHEETS-SHEET 2 Fig. 2.

lrxventor:

Thellwell R. Coggeshall,

b His Attorney.

Patented Nov. 6, 1951 UNITED ES PATENT OFFICE QUICK-RZZZTQE VALVE I Thellwell R. Coggeshall, Bala Cynwyd, Pa., assignor to General Electric Company, a corporation of New York Application November 29, 1943, Serial No. 512,180

2 Claims. v1

My invention relates to a fluid actuated opcrating mechanism for an electric circuit breaker, and more particularly is an improvement on United States Letters Patent 2,292,095, granted August 4, 1942, upon an application of Carl Thumim and assigned to the same assignee as the present application.

Fluid actuated operating mechanisms have become quite popular in recent years, particularly since the extensive use of the gas blast circuit breaker. As a matterof fact, such fluid actuated operating mechanisms are now being generally used whether the circuit breakers are of the gas blast type or not, due to numerous advantages thereof. It is essential that such fluid actuated operating mechanisms be trip-free so that the means to be actuated, such as the circuit breaker, can be released with respect to the fluid actuated operating mechanism during the course of the closing stroke and prior to completion thereof.

It is an object of my invention, therefore, to provide a new and improved fluid actuated operating mechanism for an electric circuit breaker.

It is another object of my invention to provide a new and improved dump valve for the fluid actuated operating mechanism of an electric circuit breaker so as greatly to decrease the time within which reversal of the operating mechanism during a circuit breaker closing operation can occur.

' Further objects and advantages of my invention will become apparent as the following description proceeds, and the features of novelty which characterize my invention will be pointed out with particularity in the claims annexed to and forming a part of this specification.

' For a better understanding of my invention, reference may be'had to the accompanying drawings in which Fig. 1 diagrammatically illustrates an electric switch embodying the fluid actuated operating mechanism of my invention, Fig. 2 is an enlarged sectional view of a portion of Fig. 1, Fig. 3 is a sectional view of a modification of my invention, and Fig. 4 is a view taken on line 4-4 of Fig. 3.

Referring now to Fig. 1 of the accompanying drawings, I. have illustrated my invention in connection with an electric switch, such as a circuit breaker having contact structure l0, whose op: erating mechanism II is fluid pressure actuated to close the circuit breaker. This circuit breaker is schematically illustrated as a three-pole switch which is biased to the circuit open position by suitable means, indicated as aspring 2. 'I'he contact structure H] of the circuit breaker is arranged to control an electric circuit comprising conductors |3, H and I5. As shown in elevation, the operating mechanism II is of the roller toggle type and comprises an operating crank Hi, and a pivotally mounted lever H. The crank I6 is mounted on a stationary pivot I8 and pivotally connected at I!) to a circuit breaker operating rod indicated schematically in part by the dash-dot line 20'. For actuating the crank I6 clockwise to close the circuit breaker comprising contact structure It, the lever H is mounted on a stationary pivot 2| and provided at its free end with a roller 22 mounted on a pin 23. The roller 22 engages the roller 24 mounted on a pin 25 at the end of crank -|6 opposite its attachment to operating rod 20.

For holding the operating mechanism in the switch closed position illustrated, there is provided a prop or latch 26 which, as shown, is mounted on a rotatable shaft 21 to which is also fastened the lever 28. For the reduction of friction load the prop 26 is preferably arranged to engage a second roller mounted on the pin 23 and similar to the roller 22. A suitable spring 29 is provided for biasing prop 26 in a clockwise direction, which clockwise movement is limited by a stop 30 which engages lever 28. It will be obvious that the operating mechanism described is free to collapse upon a predetermined counterclockwise movement of the prop 26 and thereby to allow the opening of the circuit breaker providing there is no support or force against the roller 22 to hold it in the illustrated position when the latch or prop 26 is moved out of holding engagement with its associated roller.

For actuating the prop 26 in the tripping direction, counterclockwise as illustrated, suitable electromagnetic means comprising a winding 3| is provided. As shown, the tripping winding 3| is arranged to be energized in response to the operation of a protective relay 32 or a tripping control switch 33. The protective relay 32 is illustrated simply as an overcurrent relay connected to be energized from a current transformer 34 in the circuit conductor l3. It will be understood of course that any number of relays may be employed in accordance with the art of circuit protection. Also as shown, the circuit of the winding 3| which includes the conductors 35 and 36 may also include the contacts 31 of a circuit breaker a auxiliary switch which is closed when the circuit breaker is closed and open when the circuit breaker is. opened.

The operating mechanism ll described thus far is not my invention but is disclosed and claimed in copending application, Serial No. 512,185, Westervelt, now Patent 2,378,270, filed concurrently herewith and assigned to the same assignee as the presentapplication.

For actuating the operating mechanism H to close the circuit breaker having contact structure I0, I provide fluid pressure actuated means such as a fluid motor 38 comprising a cylinder 39 within which is slidably mounted a piston 40 carrying a piston rod 4|. This rod on its up stroke upon the admission of fluid under pressure beneath the piston 49, engages the roller 22 whereby to move the lever 11 clockwise until the parts of the operating mechanism II are positioned as shown in the drawing with the circuit breaker in the closed position. The prop or latch 26, unless its winding 3| is energized, by virtue of spring 29 drops in under its associated roller to hold the circuit breaker closed after which the piston 40 returns to its lower position. While any suitable fluid may be provided to raise the piston 40, it is usual to use air under pressure in a receiver or tank 42 from which the air is supplied to the cylinder 39 through control valve means 43. On the up stroke of the piston 4!! suitable energy storage means, such as the spring 4|, is compressed to effect a down or return stroke of the piston 40 to the lower position shown. This down stroke operation follows the cutting off of the air supply of the valve 43 through the medium of a dump valve generally indicated at 44, which embodies my invention and which will be described in greater detail hereinafter;

The control valve 43, best shown in Fig. 2, is in many respects quite similar to the control valve disclosed in my copending application, Serial No. 512,179, filed concurrently herewith and assigned to the same assignee as the present application, now Patent 2,381,336. This control valve is shown as of the pilot differential type embodying a pilot valve 45, and a main valve means such as the piston operated valve 45. Also as shown, it includes an exhaust valve 41 for release of air to atmosphere from behind the dump valve 44 and from the delivery portion 48 of the valve body. For pressure equalization on both sides of the piston for operating main valve 43, it is provided with a bleed hole 49. The pilot valve 45 is biased to the closed position by means of a spring 59 acting through rod When the pilot valve 45 is opened it permits the fluid in the space 52above piston operated main valve 43 rapidly to exhaust to atmosphere so that the fluid pressure beneath piston operated main valve 46 causes the main valve to move upwardly against the bias of spring 53. It will be observed that in, this connection the main piston operated valve 46 and the pilot valve 45 are substantially identical to the valve disclosed and claimed in Thumim et a1. Patent 2,310,130, granted February 2, 1943, and assigned to the same assignee as the presen application.

For opening the pilot valve 45, there is provided electromagnetic means comprising an armature 54, a magnetic housing 55, a pole piece comprising the magnetic elements 56, 51 and 58 and a valve opening winding 59. As illustrated, the electromagnetic means is of the plunger and solenoid type with the armature 54 forming a part of the pilot valve 45; In order to hold the armature 54 in the attracted position after it is moved to this position, the pole piece" magnetic element 51 is of permanently magnetic material, examples of which are well known to the art.

The pilot valve 45 is normally maintained in closed position by virtue of spring 50'. However, when the pilot valve 45 is opened in response to the attraction of the armature 54 the pressure in the space 52 which is constructed for minimum volume is quickly exhausted to atmosphere thereby unbalancing the pressure on main piston operated valve member 46. Simultaneously with the opening of the main valve 46 the exhaust valve 41 is moved to the closed position so as to seal the outlet of the delivery portion 48 of the control valve 43 against loss to atmosphere through the exhaust ports 41.

For closing the circuit breaker comprising contact structure In there is provided a closing control circuit for the valve opening winding 59. As shown in Fig. 1, this circuit includes a closing control switch 60, contacts 6| of a minimum pressure switch 62 which opens when the pressure in the tank 42 falls below a predetermined value, a conductor 63, b auxiliary switch contacts 64 0f the circuit breaker comprising the contact structure I0, a conductor 65, the contacts 66 of a short time delay circuit opening relay 61 whose winding 68 is energized upon closure of the closing control switch 60, a conductor 69, the valve opening winding 59, and the conductor 10. The opening of the circuit breaker closing control circuit by the slightly delayed contacts 66 of the relay 6! insures a positive opening of the control valve 43 in response to the energiza'tion of its winding 59 and also prevents reclosure of the circuit breaker as long as the control switch 69 is kept closed. In other words, with a single closure of the control switch 69 only one closure ofv the circuit breaker comprising contact structure Hi can be effected.

In order quickly to return the piston 40 to the down position shown at the end of a circuit breaker closing stroke, means are provided for effecting the closure of valve means 43 to cut off the pressure supply at the end of the piston stroke when the circuit breaker is fully closed. As shown, this means comprises a valve closing winding 1| so wound and connected to be energized that its polarity is opposite to the polarity of the opening winding 59 and is such as to neutralize the holding flux of the permanent magnet 51' whereby to release the plunger 54 for the valve closing movement. In order to insure the energization of the valve closing winding H at the proper moment the circuit at this winding is controlled by a limit switch 12 which is actuated to the closed position in response to the move.- ment of the piston 49 so as to close its contacts 13 in the circuit 'of the winding II when the breaker is fully closed. As shown, the circuit of the valve closing winding H includes the contacts 13 of the cutofi or limit switch 12, the conductor 14, the valve closing winding II and the conductor 15.

In order to insure afast or earlier opening of the circuit breaker structure I0 when it is closed during an abnormal circuit condition, I provide means for substantially simultaneously tripping the circuit breaker and effecting the closing of the valve means 43. As shown, this means comprises a valve closing winding 16 which is independent of the winding H and which is wound and connected to be energized to have a polarity such as to neutralize the magnetic holding effect of the permanent magnet 51 whereby to release the plunger 54 to close the valve 43 and to enthe shoulder 86.

ergize the trip circuit comprising the tripping winding 3| of the operating mechanism The circuit for the valve closing winding 16 includes the contacts of the protective relay 32 and the trip switch 33 in parallel, the conductor 35, the circuit breaker a auxiliary switch contacts 31, a conductor 11, the valve closing or neutralizing winding 16 and a conductor 18. It will be observed that winding 16 and trip coil or winding 3| are always simultaneously energized.

The control arrangement of the circuit breaker and the valve means 43 is disclosed and claimed in my copending application, Serial No. 512,179, referred to above, now Patent 2,381,336.

In accordance with my present invention, I have provided a new and improved dump valve 44 which permits a much faster reversal of the piston 48 of fluid motor 38 when for example, the circuit breaker is closed on afault condition. This dump valve, generally indicated at 44, is in certain respects quite similar to the dump valve disclosed in Thumim Patent 2,292,095, and comprises a cylinder portion 80 interposed between the cylinder 39 of fluid motor 38 and the control valve 43. Mounted within cylinder 8|) is dump valve member 8| which comprises a skirted piston with the skirt extending toward control valve 43. Suitable ports 82 are provided in the valve member 8| through which fluid from source 42 may flow to cylinder 39. A suitable valve stem 83 is connected to dump valve member 8| and is guided for reciprocal movement in opening 84. A spring 85, presses against a shoulder 88 on valve rod 83 and normally biases the dump valve member 8| to the position shown in Fig. 1 so as to uncover the large escape ports 81 which quickly vent the cylinder 39 to atmosphere. my invention the ports 82 in the dump valve member 8| are closed by a check or non-return type admission valve 88 which is biased to the closed position by spring means 89 also engaging When valve means 43 is opened, fluid under pressure enters the cylinder 80 of the dump valve 44 and moves the dump valve member 8| to the left against the bias of spring means 85 to close the exhaust ports 8! since spring means 85 is constructed to exert a smaller force on shoulder 86 than spring 89 exerts on valve 88. coincidentally with the closing of ports 81 the air under pressure opens non-return valve or admission valve 88 to admit fluid under pressure to the cylinder 39. The spring means 89 of the nonturn valve becomes so compressed that when air is subsequently exhausted from the space 48 of valve 43 the non-return valve 88 is closed very quickly whereupon the dump valve member 8| is moved more rapidly to uncover the ports 81. I have found that in accordance with my invention the dump valve member 8| operates almost five times as fast as similar dump valves not embodying my invention.

In view of the detailed description given above the operation of the arrangement embodying my invention will be more or less obvious to those skilled in the art. With the circuit breaker in the position shown, closing of switch 33 or energization of protective relay 32 will cause latch 26 to be rotated in a counterclockwise direction whereupon opening of the circuit breaker will result. To close the circuit breaker closing switch 6|! is operated with the consequent energization of valve opening winding 59 whereupon control valve 43 is opened. Fluid under pressure from source 42 will move dump valve member 8| to the left as viewed in Figs. 1 and 2 to closed escape ports 81. Non-return valve 88 will also open to.

In accordance with permit the fluid under pressure to enter cylinder 39 and cause piston 48 to move upwardly to close the circuit breaker comprising contact structure l0. As soon as the circuit breaker reaches its fully closed position piston 40 engages limit switch 12 which closes its contacts 13 energizing valve closing winding 1|. As a result of the energization of the valve closing winding 1| control valve 43 is closed and as a result thereof nonreturn valve 88 automatically is closed with high speed and dump valve member 8| moves to the right to permit the piston 40 to return to its lowermost position under the bias of spring means 4| at high speed so that if circuit breaker contact structure ||l should quickly re-open piston rod 4| will notinterfere with its opening movement. The operation will be similar if the circuit breaker is closed on a fault condition except that in this case valve closing winding I6 will be energized to function in a manner similar to that when valve closing winding H is energized.

It will be observed that with my arrangement I have provided a new and improved dump valve of simple and rugged construction which is adapted instantly to reduce the back pressure resulting from the rapid reversal of fluid motor 38 so that a pneumatically trip-free circuit breaker is obtained in every sense of the word.

It will be noted that one of the factors which controls the speed of operation of dump valve 44 is the volume of the space 48 of control valve 43. If this volume is reduced to an absolute minimum a still higher speed of response of the dump valve 44 will occur. To this end there is shown in Figs. 3 and 4 a modification of my invention in which a still higher speed of operation of the dump valve may be obtained. The corresponding parts of Figs. 3 and 4 are designated by the same reference numerals as in Figs. 1 and 2. 'In this case the dump valve 44' also comprises the cylinder within which is reciprocally mounted the dump valve member 8|. The skirt of the dump valve member 8| extends in the opposite direction from the skirt of the dump valve mem ber 8| of Figs. 1 and 2 greatly to decrease the volume between the dump valve 44 and the delivery portion of the control valve 43. As may be observed from Fig. 4, the delivery port 48' of control valve 43 registers with the blank portion of the dump valve member end wall. With this arrangement the dump valve receives an opening impulse from the pressure front as it is liberated from the rapidly opened control valve 43' whereupon the dump valve is efiectively moved to cover the exhaust openings 81 before the non-return valve 88 opens to admit air to the cylinder 39. With this arrangement it is possible to dispense with one of the springs or 89 and instead provide just a single spring bearing against the nonreturn valve 88. This single spring will then function to not only keep the flapper valve against the dump valve face, but it will also act as a dump valve return spring.

While I have described what I at present consider the preferred embodiments of my invention, it will be obvious to those skilled in the art that various changes and modifications may be made without departing from my invention and I therefore aim in the appended claims to cover all such changes and modifications as fall within the true spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. A quick release valve mechanism comprising a chamber having inlet means, outlet means and exhaust means therein, piston means having two working faces and being slidably disposed in said chamber, means comprising an opening in said piston means for affording communication besaid valve means toward. its closedv position, a

valve stem movable with-said piston means, an

-opening in a wall of said chamber in which said valve stem is slidable, a. shoulder on said valve stem, second spring means interposed between said shoulder and said wall of said chamber for biasing said piston means in'a direction toward said inlet means and-away from said exhaust means, said second spring. means being constructed to exert a smaller force on said shoulder than the force exerted on said valve means by said first spring means so that fluid pressure from said inlet means is efiective to move said piston means toward said outlet means to close said exhaust means before Substantial opening of said valve means.

2. A quick release valve mechanism comprising a chamber having an inlet and an outlet opening and an exhaust port therein, a piston in said chamber having an opening therein, a valve stem movable '-with said piston, an opening in a wall of said chamber in which said valve stem is slidber on said piston, first spring means interposed between said shoulder and said valve member for normally biasing said valve member'in 'a direction to close-said opening in said piston, said piston being slidable in said chamber to close said exhaust port in response to pressure fluid supplied to said chamber through said inlet passage, and second spring means interposed between said shoulder and said wall of said chamber for biasing said piston in a direction to open said exhaust port, said second spring means being constructed to exert a smaller force on saidshoulder than the force exerted on said valve member by said first spring means;- I

THELLWELL R. COGGESHALL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,107,849 Schoen Aug. 18, 1914 1,356,298 McGregor Oct. 19, 1920 1,361,904 Rhodes Dec. 14, 1920 1,652,360 Jackson Dec. 13, 1927 1,697,352 Ferris Jan. 1, 1929 1,726,102 Forman Aug. 27, 1929 2,225,518 Blasig Dec. 1'7, 1940 2,252,418 Shelley Aug. 12, 1941 2,292,095 Thumin Aug. 4, 1942

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