US2525470A

US2525470A - Valve mechanism

Info

Publication number: US2525470A
Application number: US578236A
Authority: US
Inventors: Benjamin P Baker; Leon R Ludwig; James M Cumming
Original assignee: Westinghouse Electric Corp
Current assignee: CBS Corp
Priority date: 1945-02-16
Filing date: 1945-02-16
Publication date: 1950-10-10
Anticipated expiration: 1967-10-10

Description

Oct. 10, 1950 B. P. BAKER ETAL 7 2,525,470

VALVE MECHANISM Filed Feb. 16, 1945 2 Sheets-Sheet 2 WITNESSES: E I p50 Z lNtgIlTtgRS erg 0mm rer' eon q nag and Jbme/W. C urnm/ny.

W97! 4 BY 2 Patented Oct. 10, 1950 2,525,470 VALVE MECHANISM Benjamin P. Baker, Turtle Creek, Leon R. Ludwig, Wilkinsburg, and James M. Cumming, Turtle Creek, Pa., assignors to Westinghouse Electric Corporation, a corporation of Pennsylvania Application February 16, 1945, Serial No. 578,236

18 Claims.

This invention relates to fluid-pressure discharge-valve devices, and more particularly to a blast-valve mechanism designed for rapid operation to supply compressed gas for extinguishing the are drawn between contact elements of a large circuit breaker.

In order to minimize the fire hazard and to secure the advantages of fluid-pressure control, circuit-breaker equipments of modern design have been constructed for operation by fluid pressure, such as compressed air, and have been provided with means for extinguishing the are drawn upon separation of the contact elements comprising a blast-valve mechanism operative at the proper instant to subject the contact elements to a sudden blast of fluid under high ressure.

A blast-valve mechanism designed for such service must be adapted for operation at high speed and for quick response to the initial tripping operation of the circuit breaker, inasmuch as it is desirable to insure operation of the circuit breaker as a whole within an interval time corresponding to approximately three cycles, assuming that the circuit breaker is employed in 60-cycle alternating-current service. The blastvalve element is necessarily of large area, approximating ten square inches in some cases for example, and should be operative under a force sufficient to control the supply of fluid under a high pressure, which may be in the neighborhood of 350 pounds per square inch. It will thus be seen that unusual problems confront the designer of a blast valve suitable for rapid operation, to

control the large volume of fluid at high pressure which is required in circuit-breaker service.

One object of our invention is the provision of an improved blast-valve mechanism operable at high speed and fulfilling the requirements mentioned in the foregoing paragraph.

Another object of our invention is the provision of a fluid pressure actuated blast valve for a circuit breaker constructed and arranged for instantaneous response to energization of anelectroresponsive trip mechanism.

Still another object is the provision of a highspeed fluid-pressure operative blast-valve mechanism including electroresponsive trip mechanism and means for automatically resetting the trip mechanism during each operation of the blastvalve element.

It is still another object of our invention'to provide an improved blast-valve mechanism for a circuit breaker comprising a main valve element; fluid-pressure means for actuating that i render the pilot valve inoperative; and electroresponsive means for actuating the trip mechanism.

Another object of our invention is the provision of a blast-valve mechanism in which the main valve element and the fluid-pressure responsive means for operating it into and out of seating position are so constructed as to permit sufficient lost motion therebetween to divide the force of impact of the valve element on its seat during a closing operation, thereby reducing the tendency of the valve to engage the seat with a damaging force.

A further object of our invention is the provision of a fluid-pressure actuated blast-valve mechanism including an electroresponsive magnet assembly for actuating the tripping mechanism associated with the valve device, to ether with circuit means for the electromagnet comprising a switch which is initially closed, to permit energization of the coil of the magnet by a relatively high current, and means for opening the switch uponinitiation of a tripping operation for shunting into the circuit a resistance limiting the current ultimately supplied to the coil, thus rendering feasible the use of a low-inductance coil having relatively few turns to minimize the time constant of the circuit.

These and other objects of the invention will be apparent in the following more detailed description thereof, taken in connection with the accompanying drawings, in which:

Figure 1 is a fragmentary elevational view illustrative of an elementary form of circuit-breaker apparatus having associated therewith a blastvalve mechanism constructed in accordance with the invention;

Fig. 2 is an enlarged detail sectional view of the blast-valve mechanism shown in Fig. 1; and

Fig. 3 is a sectional view of a blast-valve mechanism constructed in accordance with a different form of the invention and adapted to be substituted for the blast valve shown in connection with the circuit breaker of Fig. 1.

As shown in diagrammatic form in Figure 1 of the drawings, the essential elements of a circuit-breaker apparatus l0 may comprise a suitably insulated supporting frame (not shown) carrying a housing I l formed of insulating material, and having an arc chamber l2 the upper end of which is closed by a plate I4 having an orifice I5 and constituting the stationary contact element of the circuit breaker. Mounted within the housing H) at the lower end of chamber [2 is a metal body 15 having a bore H in which is slidably mounted a fluid pressure responsive movable contact element I8, which is normally urged upwardly by a spring is into circuit closing engagement with the portion of plate I4 adjacent the orifice l5. Apertures 2! are formed in the body it to permit flow of air or other gas from a passageway 22 at the lowermost end of the insulating housing lfl to the chamber [2. The circuit breaker l may be one of a plurality of units arranged in stacked formation, if desired, and in the form here illustrated is adapted to control a circuit which includes a terminal member 23 on the plate E4, the movable contact element 18, the body it and a terminal member 24 carried on the body. The lower end of the insulating housing I i is connected by suitable means (not shown) to a flange 25 formed on the casing structure 26 of a blast-valve mechanism which is generally indicated by the reference character 30. The blast-valve casing 26 has an inlet portion with a flange 3i suitably connected to a conduit 32, which is associated with a reservoir or other source of fluid under pressure (not shown).

Referring to Fig. 2 of the drawings, the casing structure 23 of the blast-valve mechanism 30 has formed therein an inlet passage 33 which is adapted to communicate with the source of fluid pressure, and has mounted in its upper portion a valve-seat member 34 having formed therein a discharge passage 35 which, it will be understood, communicates with the passage 22 and arc chamber 12 formed within the housing I! shown in Fig. l. Slidably mounted in a bore formed in an extension 37 of the seat member 34 is a valve element 38, which is normally held in engagement with an annular seat 39 formed on the seat member, under the force exerted by a coil spring 43 which is interposed between an inner surface of the valve element and a lower wall of the passage 33. In the form of the Valve apparatus shown in Fig. 2, the valve element 38 is disposed for movement along a substantially vertical axis. Formed within the valve element is a cavity within which is loosely fitted the enlarged head of a connecting member 42 havin screw-threaded engagement with the upper end of a valve stem 43, which extends through a bore 44 formed in the casing structure and into a piston chamber 45. A threaded ring 4 is screwed into the valve element 38 for retaining member 42.

A piston 46 is operatively mounted in the piston chamber 45 for operating the valve element 3S and is provided with a centrally disposed bore into which the lower end of the stem 43 is threaded. A coil spring 41 is interposed between the piston 46 and the lower wall of the casing structure for urging the piston upwardly, as shown in the drawing. The piston is locked in place on the stem 43 through the medium of a screw-threaded member 48 secured to the stem, the uppermost position of the stem being determined by engagement of a sealing shoulder 49 formed thereon with a suitable seat formed on the casing adjacent bore 44, it being noted that a small space is thus left between the upper surface of the piston 45 and the upper wall of the piston chamber 45. By reason of the lost motion provided in the connection between the member 42 and the valve element 38, the latter is held in seating engagement with the seat 39 under the force exerted by the spring 40, independently of the spring 41 acting on piston 43. The valve stem 43 and piston are also urged upwardly by means of a pair of coil springs 50 and Si, which are mounted within the spring 46 and interposed between the casing and an annular element 52 fitted over the stem and adapted to engage a shoulder formed on the connecting member 42.

For controlling the supply of fluid under pressure from the inlet passage 33 to the piston chamber 45, there is provided a pilot-valve element 53 which is slidably mounted in a bore 54 formed in the casing in communication with the piston chamber. Formed in the casing in coaxial alignment with the bore 54 is a somewhat larger bore 56, which has slidably mounted therein a cylindrical resetting element 57 having an annular valve seat 58, on which the pilot valve 53 is adapted to be held seated under the force of a coil spring 59 that is interposed between the pilot valve and the lower wall of the bore 54. The resetting member 51 has a central opening to within the seat 58, and is urged downwardly toward sealing engagement with an annular rib 64 formed on the casing, by the force of a coil spring 63 interposed between a suitable shoulder portion of the resetting element and a ring element '64 having screw-threaded engagement with the casing.

The casing structure 26 is further provided with spaced extension portions 56 carrying a pin 8?, on which is pivotally mounted a trip lever 68 having oppositely extending arm portions 69 and l6 and a third arm portion H, which extends downwardly at an angle of approximately 90 from the other arm portions, in the form of the device illustrated. The arm portion 70 of the trip lever carries a pin 13 having a lost motion pivotal connection with the lower end of a valve stem 14, the upper end of which is adjustably secured to a release valve element 15 that is slidably mounted in a bore 16 formed in the casing. The release valve element 15 is adapted to engage an annular seat 71, for cutting 01? communication between a port 18 in the wall of the piston chamber 45 and an atmospheric exhaust port 79. The space 8| above the valve element 15 is open to the atmosphere through a port formed in a cap structure 82 secured to the casin structure. It will be understood that the trip lever 68 is so balanced and arranged that it normally assumes the position in which it is shown in Fig. 2, with the valve element 15 held in unseated posifdon. When in this position, the arm portion 10 of the trip lever engages an adjustable stop bolt 85 secured to a portion of the casing bridging the extension portions 66.

For operatively associating the trip lever 68 with the pilot-valve element 53, there is provided a substantially horizontally dispose-d lever 88 which is fulcrumed on a pin 89 carried in 0. depending U-shaped portion 96 of the casing structure. One end of the lever 38 closely adjacent the pin 89 is pivotally connected by means of a pin 92 to a clevis 93 having screw-threaded engagement with a valve stem 94 of the pilotvalve element 53. The opposite end of the lever 88 has a suitably formed tip 55 which is able with a notch 91 formed in the lowermost end of the arm portion H of trip lever 68. The fulcrum pin 89 is not directly secured to the U-shaped portion 99 of the casing structu e, but is yieldably supported thereon through the medium of a fulcrum member 99 and a relatively heavy spring I interposed between the fulcrum member and the lower wall of the U-shaped portion. It will thus be seen that the lever 88 is yieldably supported from the pin 89; and that, so long as the pilot-valve member 53 and trip lever 68 are held stationary, the spring I00 will remain effective to hold the tip 96 of the lever in engagement with the notch in the trip lever 68. It should-be understood that the pin 89 is fitted in a slot (not shown) formed in the lever 88, in order to permit the desired operation thereof, as hereinafter explained. The casing structure may be provided with a pair of parallel guide portions I02 disposed on opposite sides of the lever 88 for preventing undesired lateral movement thereof.

At a point intermediate the pin 88 and the tip 96, the lever 88 is provided with a pin I05, which extends through a slot I06 formed in a portion of a clevis I0I carried an the lower end of the member 48 to which the piston stem 43 is secured. The pin I05 is also secured in a cage element I09 having guide portions straddling the lever 88, which cage portion is slidably fitted on the clevis I0I in operative alignment with the lower end of a coil spring H0 carried by the member 48. The spring I I0 is attached to the member 48 by engagement with suitable grooves formed therein, and extends downwardly through an aperture III formed in the casing structure. It will be understood that, upon downward movement of the piston 46, as hereinafter explained, the spring IIO will be brought into engagement with the cage element I09, after which the force of the spring will be exerted on the lever 88 through the medium of the pin I05.

Electroresponsive magnet means is provided for actuating the trip lever 68, comprising a magnet assembly II5 supported on an extension II6 of the casing structure and including a coil I I1 and a movable armature I 48 which is secured to a plunger II9 extending into the coil. The lower end of the plunger I I9 is pivotally connected through the medium of a pin I to the arm portion 69 of the trip lever 68. When the coil H1 is deenergized, the armature H8 is adapted to rest on suitably formed stop elements I22 carried by the magnet assembly, as shown in the drawing. According to our invention, the coil II! is wound with relatively few turns to limit the inductance of the coil, and thus to minimize the time constant of the energizing circuit thereof. In order to permit safe use of sufficient energizing current for the coil without the risk of damage thereto, the energizing circuit is provided with a suitable resistance together with means for shunting such resistance out of the circuit during substantially the first third of the time interval durin which current in the circuit is building up from zero to its maximum value.

In Fig. 2 of the drawings, an energizing circuit for the coil III is illustrated diagrammatically as including a conductor I25 connected to a suitable energizing system indicated generally by the rectangle I26, the windin of the coil, a resistor I21, and a return conductor I28 leading to the energizing system. The energizing system I'26 may include a source of electric energy under the control of a manual switch or relay responsive to a fault in the main circuit.

Disposed in shunt relation across the resistor casing structure, while the contact element I 3I is carried on. an arm I formed of insulating material and suitably secured to the trip lever 68 adjacent the pin 61. It will be apparent that, with the trip lever 68 disposed in its normal position as shown in Fig. 2, the movable contact element I3I engages the stationary contact element I30; and that, upon clockwise tilting of the trip lever, the contact elements will be separated. Formed in the tube I32 is a restricted passage I36, which communicates with the passage 18 formed in the casing and opens at a nozzle disposed closely adjacent the normally engaged contact elements I30 and I3I. Through this restricted passage fluid under pressure may be supplied, as hereinafter explained, for extinguishing any arc drawn during separation of the contact elements.

When the circuit-breaker equipment is conditioned for operation, fluid under pressure from the source is supplied to passage-33 and aids the spring 40 in maintaining the valve element 38 in engagement with the seat 39. The pressure of fluid in the passage 33 also acts against the resetting element 51 to hold it seated on the seating surface 6|, thus augmenting the force exerted by spring 63, while the pilot-valve element 53 is maintained in engagement with the seat 58 under the combined forces of springs 59 and I00, due to interlocking engagement of the end of the lever 88 with the trip lever 68. At the same time, the piston chamber above the piston 46 is vented to the atmosphere by way of the assage I8, bore I6, and port I9, since the release valve I5 is disposed in unseated position by the trip lever 68.

When the trip circuit for the trip coil II I is energized through the usual operation of a faultresponsive relay or other means (not shown) for initiating operation of the circuit breaker, the full current available is supplied through the winding of the coil by way of the circuit including conductor I25, the coil winding, the connected contact elements I30 and I3I and conductor I28, with the result that the armature I I8 is pulled upwardly for turning the trip lever 68 in a clockwise direction about the ,pin 61. Initial movement of the trip lever 68 disengages the arm II thereof from the tip 96 of lever 88, whereupon pressure of fluid in the inlet passage 33 becomes effective to force downwardly the pilot-valve element 53, thus supplying fluid under pressure from the inlet passage through the opening in the resetting element to the piston chamber 45. As the pilot valve 53 moves downwardly in opposition to the force of the spring 59, it acts through the medium of stem 94 and pin '92 to tilt the lever 88 in a clockwise direction about the fulcrum pin 89.

The piston 46 is at once shifted downwardly by the fluid pressure acting thereon in opposition to the force of spring 41, and acts through the medium of the stem 43 and connecting element 42 to move the valve element 38 away from the annular seat 39. Fluid under pressure is thus supplied from the inlet passage 33 to the discharge passage 35 and acts to aid downward movement of the valve element 38, while supplying a blast of fluid under pressure through the passage 22 to the arc chamber I2 shown in Fig. l. The pressure of fluid thus supplied to the chamber I2 quickly forces the movable contact element I8 downwardly and away from the stationary contact element I4, and the fluid is thereupon discharged from chamber I2 by way of the orifice I to extinguish the arc. It should be understood that any well known form of auxiliary or isolating contact mechanism (not shown) can be associated with the circuit breaker Ill for maintaining open the circuit controlled thereby, following the initial arc extinguishing operation of the elements shown in Fig. 1, as just explained.

In turning clockwise about the pin 61, the trip lever 68 carries the pin I3, valve stem 14, and valve element I5 downwardly until the valve ele ment engages the seat I! for closing communication between the piston chamber 45 and the atmospheric port I9. Meanwhile, however, the resistance I21 has been shunted into the circuit for the coil I IT by operation of the movable switch contact element I3! away from the stationary element I30 due to operation of the trip lever 68. Any are drawn between the contact elements is extinguished by discharge of fluid under pressure from the nozzle in insulating member I32, the fluid being supplied from the piston chamber 45 by way of passage I8 and restricted passage I36. It should be understood that the release valve element I5 is not operative to close this restricted passage, but that the quantity of fluid under pressure lost will, in any event, be very small by reason of the quick operation of the device as a whole. It will thus be seen that the resistance I2! is quickly rendered eifective to limit the current supplied to the coil I I! to a safe value. The low inductance of the coil renders available a high tripping speed under a high initial energizing current; while, after the tripping operation is accomplished, the current is automatically reduced to prevent burning out of the coil.

Downward movement of the piston 46 in unseating the valve element 38 meanwhile continues, bringing the lower end of spring III) into engagement with the cage element I03. Since the pin I05 is disposed a greater distance from the fulcrum pin 89 than is the pin 92, and because of the greater power of spring I II] with respect to the spring 59, the lever 88 is then turned in a counterclockwise direction about the fulcrum pin r 89, thus moving the pilot valve 53 toward the resetting element 51. Downward movement of the piston 46 is limited upon engagement of that member with a stop ring I40 supported on suitable resilient elements carried by the casing structure. As the lever 88 is thus rotated in a counterclockwise direction about the fulcrum pin 89, the tip 96 thereof is carried below the latching position with respect to the arm portion II of trip lever 68. Movement of these elements to this position is made possible by reason of the fact that the resetting element 51, after engagement by the pilot valve 53, is shifted upwardly against the force of the spring 53.

As hereinafter explained, the operation of the trip lever 58 upon energization of the magnet II! of the electroresponsive means E I5 will effect the closure of the release valve '55. Upon completion of the circuit-interrupting operation of the circuit breaker, the magnet coil I I! is deenergized in the usual manner, thus releasing the armature H8 to permit counterclockwise movement of the trip lever 68 to the normal position indicated in Fig. 2. This operation of the trip lever 38 effects opening of the release valve I5 to vent fluid under pressure from the piston chamber 45 to the atmosphere; and, since the pilot-valve element'53 has already been moved to seating engagement with the resetting element 51, the springs 41, 50 and 5| are rendered effective to shift the piston 46 and stem 43 upwardly, while the valve element 38 is moved toward the annular seat 39. This movement of valve element 38 is efiected very rapidly; and, due to the fact that the pressure of fluid in the discharge passage tends to fall below that of the fluid in the inlet passage 33, the valve element is finally forced against the seat 38 by the combined action of fluid pressure below it and of the force of spring 43. The lost-motion connection between the valve element 38 and the connecting member 42 attached to the valve 43 thus permits the valve element to come to rest on the seat an instant prior to the final upward movement of the stem 43, piston 46, and elements. associated therewith, so that undesired pounding of the valve and of the valve seat is minimized. In other words, the total mass of valve element 33, valve stem 43 and piston 46 is divided to prevent driving of the valve element against the valve seat with excessive force during the closing operation.

As the spring H0 is withdrawn from the cage member I09, by reason of upward movement of the piston 46 as just explained, the lever 88 is allowed to tilt in a clockwise direction about the yieldable fulcrum pin 29, under the force exerted by the spring 33- on the downwardly moving resetting element 51 and pilot valve 83, until the r setting element again engages the seat surface EI at about the same time the tip 95 of the lever 88 is brought into locking engagement with the notch 97 in the trip lever I38. The operating parts of the valve mechanism are thus again positioned as shown in Fig. 2.

From the foregoing, it will be evident that a blast-valve mechanism constructed in accordance with the form of our invention shown in Fig. 2 can be automatically tripped and actuated at high speed to supply the desired blast of fluid under pressure for extinguishing the are drawn by the circuit-breaker contacts. By providing a tripping mechanism that is instantaneously responsive to a tripping impulse for unseating the pilot valve controlling the flow of fluid under pressure to the operating piston, the inertia of the necessarily large blast-valve element 38 and operating elements therefor can be quickly overcome to permit rapid opening movement thereof. The provision of the auxiliary switch-contact elements I30 and ISI for shunting the resistance I2? into the energizing circuit for the magnet coil, constitutes an effective means to allow use of a coil with a low inductance characteristic and an energizing current of relatively high value, without risk of damage to the coil. Fully automatic operation of the blast-valve mechanism is insured by the provision of means for effecting resetting of the trip mechanism during a valveclosing operation.

Referring to Fig. 3 of the drawings, there is illustrated a blastvalve mechanism embodying a modified form of the invention and including a casing structure I which is constructed and arranged to be assembled as part of the circuitbreaker apparatus shown in Fig. 1, in place of the blast-valve device 30 already described. The casing structure I50 is provided with an inlet passage I5I which communicates with the supply reservoir (not shown) and a discharge passage I52 through which fluid under pressure may be discharged to extinguish the arc during operation of the circuit breaker. Mounted on an annular interior flange I49 of the casing structure is a casing section I53 having formed at the lower end thereof an annular valve seat I54. The casing structure I50 includes a bottom section I55 having an annular wall I56 extending into inlet passage II and in which is formed a chamber I51. Slidably mounted within the wall I56 is a movable abutment I58, to which is secured a valve element 660, which is adapted to be urged into engagement with the annular seat I 54- under the force exerted by a coil spring I62 mounted in chamber I51. The valve element S69 is preferably secured to the movable abutment I58 through the medium of a screw-threaded extension I65 thereof, to which a locking nut I65 is applied in such a manner as to permit a slight relative movement between the two elements, in order that the force with which the valve element engages its seat may be divided on the same principle as has already been explained in connection with the apparatus shown in Fig. 2. A restricted passage I68 is formed in the movable abutment I58, for permitting supply of fluid under pressure at a predetermined rate from the inlet passa e I5! to the chamber I51.

Formed in the casing section I55 below the chamber I51 is a bore I10, in which is slidably mounted a cylindrical resetting element I1I that is normally engageable with a seat rib I12 under the force exerted by coil spring I14. The coil spring I14 is interposed between a suitable shoulder on the element HI and a ring I having screw-threaded engagement with the casing. A pilot-valve element I11 is slidably mounted in a bore I18 formed in the casing section below the bore I 10, for controlling communication from the chamber I51 through the openings in the ring I15 and in the resetting element IN to an atmospheric exhaust port I80. The pilot-valve element I11 is normally held in engagement with a seat I8I, formed on the resetting element I1!, under the upward force exerted by coil spring I82.

Extending downwardly from the casing structure I50 is a U-shaped bracket portion I85 on which is mounted a coil spring I86 supporting a fulcrum element I81. A lever I89 is pivotally connected to the fulcrum element by means of a fulcrum pin I90. The end of the lever adjacent the fulcrum pin is pivotally connected to a pin I9I carried by a clevis I92 secured to the lower end of a valve stem I93 of the pilot-valve element I11. The opposite end I94 of the lever I8? is adapted for interlocking engagement with an arm portion I95 of a trip lever I96, which is journalled on a pin I91 carried between parallel extensions I98 of the section I55.

The trip lever I96 has an arm :00 having a lost-motion connection with a pin I carried by a valve stem 202, which extends into a bore 293 in the casing section having'mounted therein a valve element 205. The bore 203 communicates through the mediumof a pipe 201 with a port 208 in the wall of the fluid discharge or blast pas- I52, the valve element 205 being adapted to engage a seat 299 to control communication from the pipe to a chamber 2I0 formed in the casing structure. A piston-valve element 2I I is slidably mounted in the chamber 2 I0, for controlling communication from that chamber to a passage 2I2 leading to the chamber I51 below the movable abutment I58. A ball-check valve 2 is interposed in the passage 2I2, for preventing backfiow of fluid from the chamber I 51 to the passage. The piston-valve element 2 II is provided with a stem 2I6 extending downwardly and outwardly of the casing, the lower end being disposed in operative alignment .with an upper surface of the lever I89. A forked member 2| 1 may be fitted over the lever I89 and slidably fitted in stem 2 I6, for preventing lateral displacement of that member.

Interposed between the lever I89 and the piston-valve element 2 II is a coil'spring 2 I8, which urges the piston-valve element upwardly to normal position, as shown in Fig. 3, in which the element cuts off communication between chamber 2 I0 and passage 2I2.

The trip lever I96 is so balanced as to assume the position in which it is shown in the drawing, so that the arm portion 200, thereof normally engages a stop member 220 secured to the casing structure. I A coil spring 22I is preferably interposed between the valve element 205 and the lower wall of the bore 203, for urging the valve member upwardly to its'unseated position; and the force of this spring is also effective to urge the trip lever I96 toward its normal position.

A third arm portion 224 formed on the trip lever I96 is pivotally'connected by means of a pin 225 to a plunger226 associated with an electromagnet assembly 221, which is supported on an extension 230 of-the casing I50. The magnet assembly includes a coil 228 operative when energized to move upwardly an armature 229 carried by the plunger 226. The electromagnet assembly 221 is preferably constructed and arranged for quick response to initially high energizing current, and has associated therewith means for limiting the current in time to prevent damage to the coil. A'construction similar to that already described in connection with the assembly I I5 shown in Fig. 2 may be provided for attaining this object; In Fig. 3, a diagrammatic circuit is illustrated as including a suitable energizing system 232 connected to one end of the coil 228, the other end of the coil being connected through a resistor 233 to the energizing system, together with a pair of switch-contact elements 235' and 236. which are connected in shunt'relation across-the resistor 233. The contact element 235 is carried by a suitably insulated member 238 secured to the casing struc ture; and the contact element 236 is mounted by means of an insulating member 239 on the trip lever I96. With thetrip lever I96-held. in its normal position, as shown in Fig. 3, the movable contact element 236 is maintained in engagement with the stationary contact element 235. Suitable arc-blowout means (not shown) may also be provide'dfor cooperation with the switch-contact elements 235 and-236.

Assuming that the circuit-breaker apparatus equipped with the valve mechanism shown in Fig. 3 is in condition for operation, and that the operating-parts of the blast-valve mechanismare initially in normal position, fluid under pressure flows from the inlet passage I5I through the restricted port I68 in the movable abutment I58 into the chamber I51 below the abutment, thusaugmenting the force exerted by spring I62 for maintaining the valve element I in engagement with the annular seat I54. When the usual trip switch or fault-responsive switch associated with the circuit coil 228 is closed, for initiating an opening operation of the circuit breaker, the coil 228 is energized through the circuit including the switch-

contact elements

235 and 236 by the maximum current available, with the result that the armature 229 and plunger 226 are moved upwardly for turning the trip lever I96 in a clockwise direction about .thefpin I91...?The arm I of the trip trip lever IE6 is thereby moved away from the lev r E89 to p rmit fluid pressure acting on the pilot valve IT! to force that element downwardly, while the lever is turned in a clockw se direction about the fulcrum pin I90. Meanwhile, the triplever I96 has effected movement of the valve element 205 into its seated position a ainst the force of spring 22I, while the contact element 236 has been moved away from contact element 235 to render the re istor 233 effective to limit further flow of energizing cur ent in the coil 228.

Wh n the pilot valve 11-! is unseated, fluid under p e sure is vented through the atmo pheric exhaust port I80 from the chamber 51 at a rat fast r than that of the flow of fluid throu h t e restricted port I68; and the pressure of fluid in the inlet passa e I5I thus becomes efiective to move the abutment and the blast-valve el ment I60 downwardly, to cause supply of fluid under pressure through the discharge passage I52 for extinguishing the are. It will be apparent that this movement of the movable abu ment and blast-valve element is rapid by reason of the large pressure area of the elements exposed to the relatively high fluid pr ssure above the valve, the force of the spring I62 being insuiflcient to interfere with the desired rapid operation.

Upon correction of the fault in the circuit which caused tripping of the circuit-breaker apparatus and, consequently, deenergization of the magnet winding 228, the trip'lever I96 is again positioned in its normal position, as shown in the drawing, and the spring MI is enabled to move the valve element 205 to its unseated position. At the same time, a needle valve 24I carried on the upper side of the valve 205 is moved. upwardly to close an atmospheric port 242, for preventing immediate loss of fluid under pressure from a chamber 243 formed at the upper side of the valve element, which chamber has meanwhile become charged with fluid leaking past the valve element 205.

The fluid underpressuresupplied to the discharge passage I52 by operation of the blastvalve element I60 is now supplied through the pipe 273? and past the unseated valve element 205 to the chamber 2I0, and forces downwardly the piston-valve element 2H for uncovering the passage 2 I2, whereupon fluid is supplied past the ball-check valve 2I4 to chamber I51. At the same time, the stem 2I6 of the piston-valve element 2!! is brought into operative engagement with the lever I89, for tilting that lever in a counter-clockwise direction about the pin I82, thus moving the pilot-valve element II'I into sealing engagement with the resetting element Ill. The resetting element is movable upwardly against the pressure of spring I14, for permitting movement of the free end I94 of the lever I88 somewhat below its tripping position to enable engagement thereof with the arm I95 of the trip lever. With the atmospheric communication from the chamber I5I thus cut off, the increase in the fluid pressure therein becomes effective to aid the spring I62 in returning the movable abutment I58 and valve element I60 to the position shown in Fig. 3, it being understood that the mass of these elements will be brought to bear against the annular seat 54 in two stages to minimize shock. Upon closure of the :blast-valve element, the pressure of fluid in the discharge passage I52 drops to that of the atmosphere, permitting the piston-valve element 2I I to be returned to the position shown by means of the spring 2 I 8.

The needle valve 24I serves to delay loss of fluid under pressure from the chamber 243 above the valve element 205; so that, in the event that the coil 228 is again energized immediately after a closing operation of the circuit breaker has been initiated and before the pressure of fluid in the discharge passage I52 and pipe 201 has been reduced to that of the atmosphere, the rapid operation of the trip lever I96 will not be impeded due to the effect of fluid pressure beneath the valve element 205. In other words, the valve element 205 is in effect unloaded for the required brief interval, for insuring quick response of the apparatus to initiate a reopening operation of the circuit breaker.

It will thus be seen that the blast-valve mechanism, as shown in Fig. 3 of the drawings, embodies many of the features of the construction and operative advantages inherent of the apparatus shown in Fig. 2. With the device shown in Fig. 3, the blast-valve element and movable abutment connected thereto are actuated upon a reduction in the pressure of fluid in a chamber which can be vented by sudden operation of the pilot valve in response to energization of a quick-acting electroresponsive trip mechanism. To insure rapid closure of the blast-valve element, the high pressure of fluid in the discharge passage through which the blast is conducted is utilized to effect equalization of the fluid pressure on opposite sides of the spring-biased movable abutment and blast-valve element, while the tripping mechanism is at the same time automatically reset to condition the mechanism for repeated operation.

Having described the invention in accordance with the patent statutes, it is to be understood that various changes and modifications may be made in the structural details thereof without departing from some of the essential features of the invention. It is, therefore, desired that the language of the appended claims be interpreted as broadly as the prior art permits.

We claim as our invention:

1. A discharge-valve mec anism comprising, a casing structure having a fluid-inlet passage and a fluid-discharge passage, valve means mounted in said casing for controlling communication from said inlet passage to said discharge passage, fluid pressure responsive means for operating said valve means, a normally seated pilot valve operable by fluid under pressure and operable for suddenly varying the pressure of fluid on said fluid pressure responsive means, trip mechanism for normally maintaining said pilot valve inoperative in opposition to the fluid pressure thereon, electroresponsive means for actuating said trip mechanism to release said pilot valve, and means for automatically resetting said trip mechanism.

2. A discharge-valve mechanism comprising, a casing structure having a fluid-inlet passage and a fluid-discharge passage, valve means mounted in said casing for controlling communication from said inlet passage to said discharge passage, movable abutment means responsive to a variation in fluid pressure for operating said valve means, a pilot valve operable by fluid under pressure for suddenly varying the pressure of fluid on said movable abutment means, a lever fulcrumed on said casing structure and operatively connected to said pilot valve, an electroresponsive'tri-p mech- 13 anism for normally positioning said lever to maintain said pilot valve inoperative, said trip mechanism being operative to release said lever to permit quick operation of said pilot valve by fluid under pressure, and means for automatically resetting said lever.

3. A discharge-valve mechanism comprising, a casing structure having a fluid-inlet passage and a fluid-discharge passage, valve means mounted in said casing for controlling communication from said inlet passage to said discharge passage, movable abutment means responsive to a variation in fluid pressure for operating said valve means, a pilot valve operable by fluid under pressure for suddenly varying the pressure of fluid on said movable abutment means, a lever fulcrumed on said casing structure and operatively connected to said pilot valve, trip mechanism cooperative with said lever for normally rendering said pilot valve inoperative, electroresponsive means operative to actuate said trip mechanism for releasing said lever whereby said pilot valve is automatically operated by fluid under pressure to cause rapid operation of said valve means, and means for automatically resetting said lever.

4. A discharge-valve mechanism comprising, a casing structure having a fluid-inlet passage and a fluid-discharge passage, valve means mounted in said casing for controlling communication from said inlet passage to said discharge passage, movable abutment means responsive to a variation in fluid pressure for operating said valve means, a pilot valve operable by fluid under pressure for suddenly varying the pressure of fluid on said movable abutment means, a lever having a fulcrum on said casing structure and operatively connected to said pilot valve, trip mechanism cooperative with said lever for normally rendering said pilot valve inoperative, electroresponsive means for actuating said trip mechanism to release said lever, and resilient means associated with said fulcrum for facilitating resetting of said lever into cooperative relation with said trip mechanism.

5. A discharge-valve device comprising, in combination, a casing structure having a fluid-inlet passage and a fluid-discharge passage, valve means mounted in said casing for controlling flow of fluid under pressure from said inlet passage to said discharge passage, fluid pressure responsive means for actuating said valve means, pilot-valve means for controlling the pressure of the fluid on said fluid-pressure means, and quickacting electroresponsive means for controlling operation of said pilot-valve means including an actuating coil having a low inductance characteristic, and energizing circuit therefor, a current-limiting resistor, and switch means operative immediately upon energization of said electroresponsive means for causing said resistor to limit the current in said current.

6. In a blast-valve mechanism for a fluid pressure operated circuit breaker, the combination of valve means operative to supply arc-extinguish.

ing fluid under pressure to said circuit breaker, fluid-pressure means for actuating said valve means, means for effecting sudden variation in the pressure of fluid on said fluid-pressure means comprising, pilot-valve means, a low inductance actuating coil associated therewith, an energizing circuit for said coil including a current-limiting resistor, and switch means for first shunting said resistor out of said circuit and operative immediately upon energization of said actuating coil to render said resistor effective to limit the energizing current.

7. In a control-valve mechanism, in combination, fluid-pressure means including a controlvalve element, means for operating said valve element, trip means normally operative to render said valve element inoperative, quick-acting electroresponsive means including a movable armature adapted to be energized for actuating said trip means to release said valve element, and circuit-controlling means actuated by said armature immediately upon energization of said electroresponsive means to limit the degree of energization of said electroresponsive means.

8. In a circuit-breaker apparatus of the type utilizing a blast of fluid under pressure for extinguishing the are drawn in operating the apparatus, a blast-valve mechanism comprising a casing structure having an inlet passage and a discharge passage, a valve member interposed between said passages, fluid pressure responsive means for operating said valve member, controlvalve means operative by fluid pressure for effecting a variation in the pressure of fluid on said fluid pressure responsive means for actuating the same, trip means normally rendering said controlvalve means ineffective, means for actuating said trip means to release said control-valve means and means for automatically resetting said trip means.

9. In a circuit breaker having relatively movable contact elements and means for directing a blast of fluid under pressure toward said contact elements for extinguishing the arc drawn during separation thereof, a blast-valve apparatus having an inlet passage and a discharge passage, blast-valve means for controlling the flow of fluid under pressure from said inlet passage to said discharge passage, a movable abutment operative by the pressure of fluid supplied from said inlet passage for actuating sai'd blastvalve means, normally seated pilot-valve means operative to an unseated position by fluid under pressure for imitating sudden operation of said movable abutment, means for normally holding said pilot-valve means in seated position including a trip mechanism, current-responsive means for actuating said trip mechanism to release said pilot-valve means and means for automatically reseating said pilot valve and for automatically resetting said trip mechanism.

10. In a circuit breaker having relatively movable'contact. elements and conduit means for directing a blast of fluid under pressure thereon for extinguishing the arc drawn during separation of said contact elements, a blast-valve device comprising a casing structure having a fluidinlet passage, a fluid-discharge passage communicating with said conduit means and an annular valve seat defining an opening connecting said passages, a blast-valve element disposed in said inlet passage for engagement with said seat, a cylinder having a piston movable therein by the pressure of fluid supplied from said inlet passage for operating said blast valve to open position, and means providing a limited lost-motion connection between said blast-valve element and said piston, said lost-motion connection rendering said blast-valve element movable into engagement with said seat under pressure of fluid in said inlet passage in advance of final movement of said movable piston in eflecting closing operation of said blast-valve device.

11. In a blast-valve mechanism for a circuit breaker, the combination of a casing structure having an inlet passage supplied with fluid under pressure, a discharge passage, and a pressure chamber, main-valve means mounted in said casing for controlling flow of fluid under pressure from said inlet passage to said discharge passage, a movable abutment operatively connected to said main-valve means and mounted in said chamber, spring means for normally positioning said valve element to cut off communication between said passages, a pilot valve operable by fluid pressure from said inlet passage to admit fluid under pressure from said inlet passage to said chamber for causing said movable abutment to operate said main-valve means, a lever operatively connected to said pilot-valve element, trip mechanism engageable with said lever for maintaining said pilot-valve element inoperative, means for actuating said trip mechanism to release said lever to permit operation of said pilot valve, and yieldable means controlled by said movable abutment for resetting said lever into engagement with said trip means following an opening operation of said blast valve mechanism.

12. In a blast-valve mechanism for a circuit breaker, the combination of a casing structure having an inlet passage supplied with fluid under pressure, discharge passage, and a pressure chamber in said casing, a main-valve disposed in said casing for controlling flow of fluid under pressure from said inlet passage to said discharge passage, a movable abutment interposed between said inlet passage and said chamber for operating said main-valve, means for admitting fluid under pressure from said inlet passage to said chamber at a restricted rate, and a pilot-valve mechanism disposed in said casing and automatically operative to vent fluid under pressure from said chamber at a more rapid rate to initiate operation of said main-valve by said movable abutment.

13. In a blast-valve mechanism for a circuit breaker, the combination of a casing structure having an inlet passage supplied with fluid under pressure, a discharge passage, and a pressure chamber in said casing, a main-valve mounted in said casing for controlling flow of fluid under pressure from said inlet passage to said discharge passage, means for admitting fluid pressure from said inlet passage to said chamber, a movable abutment subject to the opposing pressures of fluid in said inlet passage and in said chamber for operating said main-valve, pilot-valve means associated with said chamber subject to the pressure of fluid in said chamber and operative to vent fluid therefrom, trip mechanism fo normall maintaining said pilot-valve means inoperative, said trip mechanism being adapted for operation to permit unseating of said pilot valve in effecting operation of said main-valve, and means responsive to the pressure of fluid supplied to said discharge passage upon operation of said main-valve for resetting said trip mechanism and to effect closure of said pilot-valve means.

14. In a blast-valve mechanism for a circuit breaker, the combination of a casing structure having an inlet passage supplied with fluid under pressure, a discharge passage, and a pressure chamber in said casing, a main-valve mounted in said casing for controlling flow of fluid under pressure from said inlet passage to said discharge passage, means for admitting fluid pressure from said inlet passage to said chamber, a movable abutment subject to the opposing pressures of fluid in said inlet passage and in said chamber for operating said main-valve, pilot-valve means associated with said chamber subject to the pressure of fiuid in said chamber and operative to vent fluid therefrom, trip mechanism for normally maintaining said pilot-valve means inoperative, said trip mechanism being adapted for operation to permit unseating of said pilot valve in effecting operation of said main-valve, said trip mechanism including an electro-responsive movable element, fluid pressure responsive means operative to efiect resetting of said trip mechanism and closure of said pilot-valve means, and valve means controlled by said movable element for eifecting supply of fluid under pressure from said discharge passage to said fluid pressure responsive means.

15. In a blast-valve mechanism for a circuit breaker, the combination of a casing structure having a passage supplied with fluid under pressure and through which fluid under pressure may be supplied to said circuit breaker, a main-valve mounted in said casing structure for controlling flow of fluid through said passage, spring means, a movable abutment subject to the opposing ressures of said spring means and of fluid in a chamber formed in said casing for actuating said main-valve, a lever yieldably fulcrumed on said casing structure, a pilot-valve element operatively connected to one end of said lever and disposed to be operated by fluid pressure in said passage to control the supply of fluid under pressure from said passage to said chamber, a trip mechanism including a movable element engageable with the other end of said lever for normally positioning same to render said pilot-valve element inoperative, means for actuating said trip mechanism to release said lever, and means operated by said movable abutment in effecting operation of said main-valve for positioning said lever to close said pilot-valve element and to reengage said movable element of the trip mechanism.

16. A blast-valve mechanism for a circuit breaker comprising, a casing structure having an inlet passage supplied with fluid under pressure and a discharge passage through which fluid under pressure is supplied to said circuit breaker, a main-valve mounted in said casing structure for controlling flow of fluid from said inlet passage to said discharge passage, movable abutment means subject to the opposing pressures of fluid in said inlet passage and in a control chamber, means for admitting fluid pressure from said inlet passage to said chamber, a vent valve mounted in said casing structure and operable by fluid pressure in said chamber to vent fluid under pressure from said control chamber to initiate operation of said main-valve, an electroresponsive trip mechanism including a movable element, a lever yieldably fulcrumed on said casing structure and having one end operatively connected to said vent valve and the other end operatively engageable with said movable element for normally maintaining said vent valve closed, means for energizing said electroresponsive trip mechanism to permit movement of said lever to a position permitting opening of said vent valve, and a valve piston subject to pressure of fluid supplied from said discharge passage for operating said lever to close said vent valve.

17. A blast-valve mechanism for a circuit breaker comprising, a casing structure having an inlet passage and a discharge passage through which fluid under pressure is supplied to said circuit breaker, a main-valve mounted in said casing structure for controlling flow of fluid from said inlet passage to said discharge passage, mov- 17 able abutment means cooperating with said casing to form a control chamber and subject to the opposing pressures of fluid in said inlet passage and in said control chamber, means for admitting fluid pressure to said chamber, a vent valve mounted in said casing structure and operable by fluid pressur in said chamber to vent fluid under pressure from said control chamber to initiate operation of said main-valve, an electroresponsive trip mechanism including a movable element, a lever yieldably fulcrumed on said casing structure and having one end operatively connected to said vent valve and the other end operatively engageable with said movable element for normally maintaining said vent valve closed, means for energizing said electroresponsive trip mechanism to permit movement of said lever to a position permitting opening of said vent valve,

a valve piston subject to pressure of fluid supplied from said discharge passage for operating said lever to close said valve, and means for increasing the pressure of fluid in said control chamber when said vent valve is closed.

18. In a fluid pressure operated circuit breaker, relatively movable contact means constructed and arranged for operation by fluid under pressure, fluid pressure means for effecting operation of said contact means including a control valve element subject to a biasing pressure, trip means normally operative to render said valve element inoperative, electroresponsive means including a trip coil having a low inductance characteristic for actuating said trip means to release said valve element in initiating an operation of the circuit breaker, a circuit for energizing said trip coil, a current limiting resistance for said circuit, arc blowout switch means normally shunting said resistance, and means for quickly opening said switch means upon initial operation of said trip means.

BENJAMIN P. BAKER.

LEON R. LUDWIG.

JAMES M. CUMMING.

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

UNITED STATES PATENTS Number Name Date 533,283 Engberg Jan. 29, 1895 812,279 Locke Feb. 13, 1906 844,923 Cridge Feb. 19, 1907 896,402 Locke Aug. 18, 1908 1,077,319 Tatum Nov. 4, 1913 1,142,852 Simon June 15, 1915 1,629,815 Aikman May 24, 1927 1,901,679 Uebermuth Mar. 14, 1933 2,074,292 Wilkins Mar. 16, 1937 FOREIGN PATENTS Number Country Date 679,233 Germany of 1939