US3588407A

US3588407A - Puffer piston gas blast circuit interrupter with insulating nozzle member and valve acting hollow contacts

Info

Publication number: US3588407A
Application number: US657122A
Authority: US
Inventors: Russell E Frink; Stanislaw A Milianowicz
Original assignee: Westinghouse Electric Corp
Current assignee: CBS Corp
Priority date: 1967-07-31
Filing date: 1967-07-31
Publication date: 1971-06-28
Anticipated expiration: 1988-06-28
Also published as: ES355651A1; YU31493B; DE1765381A1; GB1156310A; FR1575273A

Abstract

A GAS-BLAST CIRCUIT INTERRUPTER OF THE PUFFER PISTON TYPE IS PROVIDED HAVING A PAIR OF VENTED SEPARABLE CONTACTS, WHICH MAKE VALVE-CLOSED ENGAGEMENT IN THE CLOSED POSITION. AN OPERATING LINKAGE IS PROVIDED WITH A LOST MOTION MECHANICAL CONNECTION BETWEEN THE PISTON MEANS AND THE MOVING CONTACT, SO THAT GAS PRESSURE IS BUILT UP PRIOR TO CONTACT PART. THE CONTACTS SEPARATE WITHIN AN INSULATING NOZZLE MEMBER, WHICH

GUIDES ALL OF THE GAS FLOW THROUGH BOTH VENTED CONTACTS, WHEN THEY PART DUE TO THE TAKEUP OF THE LOST MOTION.

Description

United States Patent OPEN\ 3,339,046 8/1967 Giammona et a1 ZOO/148(B) 2,442,010 5/1948 Leeds et al 200/150(G) 2,757,261 7/1956 Lingal et a1. ZOO/148(2) 3,095,490 6/1963 Cromer et al... 200/148(.1) 3,291,947 12/1966 Van Sickle ZOO/148(8) FOREIGN PATENTS 144,768 9/1935 Austria 200/l48(.1) 106,334 7/1938 Austria 200/148(.I) 369,189 9/1930 Great Britain..... 200/l48(.1) 514,359 1/1938 Great Britain 200/148(.l)

Primary ExaminerRobert S. Macon Assistant ExaminerRobert A. Vanderhye Attorneys-A. T. Stratton, Clement L. McI-Iale and W. R.

Crout ABSTRACT: A gas-blast circuit interrupter of the puffer piston type is provided having a pair of vented separable contacts, which make valve-closed engagement in the closed position. An operating linkage is provided with a lost motion mechanical connection between the piston means and the moving contact, so that gas pressure is built up prior to contact part. The contacts separate within an insulating nozzle member, which guides all of the gas flow through both vented contacts, when they part due to the takeup of the lost motion.

PATENTED-JUNZSIHYI 3,5 9,407

sum 1 OF 3 l p FIG-l.

WITNESSES IN TORS ATTORNEY PUFFER PISTON GAS BLAST CIRCUIT INTERRUP'I'ER WITH INSULATING NOZZLE MEMBER AND VALVE ACTING HOLLOW CONTACTS CROSS REFERENCES TO RELATED APPLICATIONS Applicants are not aware of any related pending patent applications pertinent to the present invention.

BACKGROUND OF THE INVENTION The invention relates to a puffer, or piston-type fluid-blast circuit interrupter in which a piston structure, providing a fluid blast, is related to the operating mechanism and provides a desirable fluid-blasting action during contact separation, with the fluid flow passing over the arc to effect its extinction. Cromer et al. U.S. Pat. No. 3,095,490 teaches, generally, a fluid-blast circuit interrupter of such a type in which the separation of the contact structure is deliberately delayed until a predetermined pressure buildup occurs. This has the advantage of providing an adequate pressure differential across a related orifice structure prior to contact part.

SUMMARY OF THE INVENTION In accordance with a preferred embodiment of the invention, there is provided an elongated insulating housing structure, interiorly of which is disposed a movable operating cylinder connected by a lost-motion mechanical connection to the movable contact structure. The movable operating cylinder has a closed end portion and slides over a stationary piston, which supports the stationary contact structure. Because of the provision of the lost-motion mechanical connection, there occurs a predetennined pressure buildup prior to contact part. The stationary and movable contacts are so arranged as to block off any venting of the gas flow during the taking up of the lost-motion during the initial portion of the Opening operation. When the lost-motion has been taken up, there occurs a separation of the separable contact structure and a consequent exhausting of fluid flow in opposite directions through the stationary tubular vented contact, and also in an opposite direction through the movable tubular vented moving contact so that an opposite double-fluid flow is achieved. A cooling structure surrounds the vented stationary contact and assures thereby a cooling of the compressed gas prior to its ejection through the are.

A general object of the present invention is to provide an improved delayed-action piston-type fluid-flow circuit interrupter in which a pressure buildup is achieved prior to contact part, and then a highly effective double-flow exhausting action is achieved.

Still a further object of the present invention is the provision of a low-cost fluid-blast circuit interrupter of highly efficient construction and operation.

Still a further object of the present invention is the provision of a highly effective delayed-action piston-type circuit interrupter in which cooled gas under pressure is ejected into the arcing region; and then a double-flow exhausting action is obtained for rapid arc elongation and efi'ective fluid flow.

Further objects and advantages will readily become apparent upon reading the following specification, taken in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 illustrates a perspective view of a three-pole circuit interrupter embodying the principles of the present invention;

FIG. 2 is a longitudinal sectional view taken through one of the interrupting assemblies of FIG. 1, the contact structure being illustrated in the closed-circuit position;

FIG. 3 is a view similar to that of FIG. 2, but illustrating the disposition of the several parts at an intermediate point in the opening operation;

FIG. 4 is a sectional view taken substantially along the line IV-IV of FIG. 2; and

FIG. 5 is a sectional view taken substantially along the line V-V of FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawings, and more particularly to FIG. 1 thereof, a reference numeral 1 generally designates a threepole fluid-blast circuit interrupter comprising three spaced pole assemblies A, B and C. As will be apparent from FIG. I, each pole assembly includes, generally, an upper end plate 2, a generally upstanding cylindrical housing 3, and a lower end plate and mechanism housing 4. Disposed exteriorly of the mechanism housing 4 is a drive crank 5 affixed to an operating shaft 6, and a generally horizontally reciprocally movable insulating operating rod 7 is pivotally secured to the external operating crank 5, as at 8, and is connected to a drive crank 9 through a pivotal connection 10. The three drive cranks 9, only one of which is shown, are affixed and rotatable with an operating drive shaft II, which is connected to a suitable mechanism 12, which constitutes no part of the present invention, and may be of the type set forth in U.S. Pat. No. 3,183,332, issued May ll, I965 to Russell E. Frink and Paul Olsson, and assigned to the assignee of the present invention.

It will be apparent from FIG. I that a suitable supporting grounded framework 14 is utilized comprising vertical channels members 15 with interbracing structural steel members I6, having horizontally extending insulating support straps 16b secured thereto, which assist in supporting the interrupting assemblies. Additionally, lower insulator supports 17 may be employed extending generally horizontally from a channel support member 160, the latter being affixed to the vertical support channels 15.

FIGS. 2 and 3 more clearly illustrate the internal construction of each of the interrupting assemblies. With reference to FIG. 2, it will be noted that there is provided the cylindrical housing 3 of a suitable insulating material having at one end thereof the end closure plate 2 having a line terminal connection 20 constituting an integral part thereof. At the opposite end of the tubular housing 3 is the operating casting 4, within which extends the rotatable operating shaft 6 having affixed thereto. as by a key pin I8, an internally disposed operating crank 19, the latter being pivotally connected, as at 20, to a pair of metallic operating links 21. The upper ends of the operating links 21, as viewed in FIGS. 2, 3, and 5 are pivotally connected to a pivot pin 22, the latter extending through apertures 23 provided in a spiderlike spring seat 24, which is fastened, as by pins 25, to the end 26a of a movable operating cylinder 26 having a closed end plate portion 26b. Interposed between the spiderlike spring seat support 24, movable with the movable operating cylinder 26, is a contact compression spring 27 having its upper end 27a bearing upon a generally frustoconical movable spring seat support 28 constituting an integral part of an elongated movable tubular vented contact rod 30. The contact rod 30 makes sliding contacting engagement, as at 3I, with a stationary sliding contact structure having a plurality of contact balls 33 interposed between a surrounding housing cage 34 and the outer surface 300 of the movable tubular contact 30. U.S. Pat. No. 3,301,986 illustrates the general construction of such a stationary sliding contact structure.

At the upper end of the movable tubular contact rod 30 is a plurality of contact fingers 35 fomied by slotting the upper end of the movable tubular contact tube 30. Interiorly of the contact tube 30, as at 36, is a metallic orifice contact member 37 threaded, as at 38, to the outer movable contact tube 30. This movable metallic orifice member 37, having an arc-resisting tip portion 370, abuts an arc-resisting stationary orifice contact member 40, with a valve sealing engagement. The orifice contact member 40 is affixed to a stationary tubular contact tube 41 which supports a fixed piston structure 43.

Preferably, the gas disposed within the interrupting housing 3 is sulfiir-hexafluoride (SF gas, under a pressure of say, for example, 60 p.s.i.

In more detail, the fixed piston 43 comprises a cup-shaped member 43a having apertures 43b therethrough and a cooling means 45 comprising a spirally arranged metallic strap 46, such as a copper strap, cooling the gas prior to its ejection into the arcing region 48. In other words, as will be obvious. downward opening motion of the end closure plate portion 26b of the operating cylinder 26 will effect a compression of the gas within the region 50 and cause the ejection thereof through the apertures 43!: provided in the fixed piston 43 and into the arcing region 48 following contact separation. Because of the provision of a lostmotion connection 52 between the operating cylinder 26 and the movable contact structure 54, as brought about by the pivot pin 22 moving through an elongated slot 55 provided in the sidewalls of the movable contact tube 30, there will be a predetermined pressure buildup within the region 50 prior to the taking up of the lost-motion 52 and a movement of the entire assembly 51 comprising the operating cylinder 26 and the movable contact structure 54. When this occurs, the compressed gas within the region 50 will be forced through the cooling structure 45 and into the arcing region 48 (FIG. 3) to become exhausted in opposite directions through the fixed tubular vented contact tube 41 and also in an opposite direction through the movable vented tubular contact tube 30, as illustrated more clearly in FIG. 3 of the drawings.

The stationary contact tube 41 is threadedly secured to a contact clamping plate 56, which is bolted, as by means of bolts 58, which pass through spacing sleeves 59 and have their ends threaded into tapped holes 61 provided in the end metallic terminal plate 2. Additionally, a deflecting button 63 is provided, being threadedly secured to the end closure plate 2 and serves to deflect the exhaust gases, as indicated by the arrows 65 in FIG. 3 of the drawings.

The exhaust gases which pass through the moveable tubular contact rod 30 are exhausted out of the end 30a thereof, and into the operating mechanism casting 4 to become cooled.

It will be observed that the compression spring 27 not only assists in providing the desired lost-motion connection 52 between the operating cylinder 26 and the movable contact structure 54, but additionally provides the desired contact pressure in the closed-circuit position of the device, as is illustrated in FIG. 2 of the drawings.

With reference to FIGS. 2 and 3 of the drawings, it will be observed that the stationary venting contact 40 is provided on the upstream side of an electrically insulating arc chamber or flow guide 67, which is secured to the fixed piston 43, an apertured clamping plate 68 provided therebetween, which assists in supporting the cooling coils of copper strap 46, for example, within the cooling structure 45.

Additional support for the fixed piston structure 43 is provided by stationary support rods 69, which extend through the end clamping plate 56 and are affixed to the end closure plate From the foregoing description, it will be apparent that counterclockwise rotative opening motion of the operating shaft 6, as effected by the operating mechanism 12 (FIG. 1), will cause, through the pair of links 21, downward compressing action of the operating cylinder 26 over the fixed piston 43. This action will continue while the contact structure 54 remains in engagement with fixed contact 40 until the pivot pin 22 reaches the lower end of the elongated slots 55 provided in the opposite sidewalls of the movable contact tube 30. When this occurs, the pivot pin 22, being driven by the operating links 21, will cause downward following opening motion of both the operating cylinder 26 and the movable contact structure 54. By this time, however, there has been considerable gas pressure built up within the region 50, and upon the subsequent contact part of the movable and

stationary contacts

40, 54, the gas will pass through the cooling means 45 and into the arcing region 48 (FIG. 3) to effect are elongation 60 within the separating movable and stationary contact orifice members 37 and 40, for rapid arc elongation and are extinction, the gas-exhausting action occurring in opposite directions out through the stationary tubular venting contact post 41 and the movable tubular venting contact tube 30. Following arc extinction, the movable contact structure .54 and operating cylinder 26 moves to the fully open-circuit position, as illustrated by the dotted lines 70 in FIG. 3 of the drawings.

CLOSING OPERATION During the closing operation, the operating mechanism 12 effects clockwise rotative closing motion of the drive shaft 6, which through the linkage 21 effects upward closing motion of both the movable contact structure 54 and the movable operating cylinder 26. This action continues until the movable and stationary contact structure 37a. 40 abut, as illustrated in FIG. 2, and continued upward closing motion of the operating cylinder 26 causes a desired compression of the compression spring 27, thereby effecting a proper contact pressure in the closed-circuit position, as illustrated in FIG. 2 of the drawings.

It will be noted that the interrupter 1 has both the stationary and moving contacts hollow, and that in the closed-circuit position (FIG. 2) the volume 50 in the cylinder chamber system 26 is sealed off from the rest of the circuit breaker interior 71 by virtue of the abutting engagement of the stationary and

movable contact structure

37a, 40, as effected by the contact compression afforded by the contact compression spring 27. The provision of the lost-motion connection 52 and the contact compression spring 27 permits the contact motion to lag behind that of the operating cylinder 26 during the initial part of the opening operation, so that a higher pressure differential can be produced at contact part by the choice of the length of the slots 55, and also by the fact that there are no open ports of any kind before contact part. Additionally, it will be noted that there is no arcing 60 during the early stages of gas compression when are interruption would not be possible because of the low pressure available. Moreover, the contact part speed can be higher since there will be an instantaneous momentum transfer when the pivot pin 22 reaches the lower ends of the slots 55. Also the energy obtained from the contact compression spring 27 is used to obtain the opening motion of the movable contact structure 54.

When all of the moving pans have reached the fully opencircuit position 70, and crank motion is arrested by the external mechanism 12 (FIG. 1), the mass of the moving contact assembly 54 will act on its mechanical train through the contact compression spring 27, thus diminishing the forces necessary to decelerate all the moving parts.

From the foregoing description of the invention, it will be apparent that there is provided a delayed-action piston-type circuit interrupter l in which the gas is not permitted to flow from the operating cylinder 26 until the pressure within the cylinder 26 has reached the value required for efficient arc interruption. This results in a maximum use of the available gas, and also makes interrupting action easier because the interrupting region has not been contaminated with ionization caused by arcing prior to the time that sufficient pressure differential has been generated to effect interruption.

Although there has been illustrated and described a specific structure, it is to be clearly understood that the same was merely for the purpose of illustration, and that changes and modifications may readily be made therein by those skilled in the art without departing from the spirit and scope of the invention.

We claim:

1. A gas-blast circuit interrupter including, in combination, means defining a stationary contact structure having an exhausting vent aperture therethrough, an elongated insulating nozzle member (67), a cooperable movable tubular venting contact (37) movable longitudinally interiorly within said nozzle member (67) at all times during arcing, said movable contact making closed abutting valvelike engagement with said vented stationary contact in the closed position, puffer piston means for generating gas pressure at the point of separation between the separable contacts and within said insulating nozzle member, operating linkage means having a lost-motion connection between the puffer piston means and the movable tubular venting contact, whereby operation of the operating linkage means first generates gas pressure within the noule member while the separable contacts remain closed, thereby preventing an exhausting flow of gas through the contacts at this time, and following takeup of the lost-motion, separation of the contacts results with all of the gas blast compelled to flow through both separable vented contacts to thereby sweep the arc interiorly within both vented contacts near a current zero for quick interruption.

2. The combination according to claim I, wherein the elongated insulating nozzle member (67) is stationary.

3. The combination according to claim I, wherein the stationary contact structure supports the elongated insulating nozzle member (67).

4. The combination according to claim 1. wherein the puffer piston means comprises an operating cylinder slidably movable over a stationary piston secured to the stationary contact structure.

5. The combination according to claim 1, wherein the lostmotion connection of the operating linkage means comprises a biasing spring (27) which biases the movable contact (30) toward the closed-circuit position.

6. The combination according to claim I, wherein the stationary contact structure is supported by an elongated support member (41 and the pufi'er piston means comprises a movable piston member which is guided by sliding over the stationary contact support (41).

7. The combination according to claim 1, wherein the puffer piston means comprises an operating cylinder which slides over a stationary piston secured to the stationary contact structure, and the other end of the operating piston has a support member to which operating links (21) are secured.

8. The combination according to claim I, wherein the movable vented contact (30) never withdraws from the elongated insulating nozzle member (67).

9. The combination according to claim I, wherein the stationary and movable contact structure is disposed interiorly within an elongated outer insulating casing (3), and the insulating casing (3) has a terminal plate closing one end thereof and has a crank casting closing the other end of the casing (3) with crank means for the operating linkage disposed therewithin.

10. The combination according to claim 1, wherein a fixed piston and the fixed nozzle member (67) are secured to the relatively stationary contact structure.

11. The combination according to claim I, wherein a cooling structure (46) is secured to the stationary contact structure. and the gas compressed by the puffer piston means is compelled to traverse the cooling structure prior to entry into the arcing region.

12. The combination according to claim 1, wherein the lostmotion connection comprises spring-biasing means to bias the movable contact against the stationary contact in the closedcircuit position of the interrupter.

13. The combination according to claim 1, wherein the puffer-piston means comprises an elongated operating cylinder (26), and an elongated outer insulating casing (3) is provided having slight clearance between it and the inwardly disposed longitudinally movable operating cylinder (26), and a stationary piston structure is secured to the stationary contact and assists in guiding the longitudinal motion of the operating cylinder 26).