US2340095A - Fluid blast circuit breaker - Google Patents

Description

\ Jan. 25, 1944; H; M. w|| cox 2,340,095

FLUID BLAST CIRCUIT BREAKER Filed April 2, 1942 4 Sheets-Sheet 1 nsuiatzbrz Insulation 1? 1a a wnmzsszs: INVENTOR ad/ i241 Howard/W. Wilcox.

Jan; 25, 1944. H. M. wlLCox 2,340,095

FLUID BLAST CIRCUIT BREAKER Filed April 2, 1942 4 Sheets-Sheet 2 [USU/527072 51 Mmzssss:

INVENTOR Howard/ 1 Wi/aox.

Jan. 25, 1944. H, M, LCOX 2,340,095

FLUID BLAST CIRCUIT BREAKER Filed April 2, 1942 sheets-sheet s J3 WITNESSES: INVENTOR a Ho ard/ 2 Wilcox.

H. M. WILCQX FLUID BLAST CIRCUIT BREAKER Jan. 25, 19,44.

FiledApril 2, 1942 4 Sheets-Sheet 4 \SD n mNN - INVENTOR Hawaraflibx zl aox.

Ai'TOR'NE WITNESSES:

.MMQ

Patented Jan. 25, 1944 UNITED STATES FLUID BLAST CIRCUIT BREAKER Howard M. Wilcox, Wilkinsburg, Pa, asslgnor to Westinghouse Electric & Manufacturing Company, East Pittsburgh, Pa, a corporation of Pennsylvania Application April 2, 1942, Serial No. 437,379

6 Claims. (Cl. ZOO-e148) The invention relates to a multipole circuit breaker of the fluid blast type wherein the arcs drawn upon interruption of the circuit are extinguished by blasts of arc-extinguishing fluid,

such as air blasts derived from a source of com- .1

pressed air.

An object of the invention is the provision of a multipole circuit breaker having a plurality of mechanically independent pole units or circuit interrupting units and an improved pneumatic system for simultaneously operating the units from a single control valve. a I

Another object of the invention is the provision of a multipole compressed air circuit breaker having a plurality of mechanically independent pole units and. a single electrically controlled valve for simultaneously causing blasts of air to be directed to all of the circuit interrupting units.

Another object of the invention is the provision of a multipole compressed air circuit breaker comprising a plurality of mechanically independent pole units each with an individual blast valve, and a compressed air operating system including a single master air relay valve for simultaneously controlling the operation of all of the blast valves. I

Another object of the invention is the provision of an improved multipole compressed air circuit breaker-that is simple, reliable in operation and relatively inexpensive to manufacture.

The novel features that are considered characteristic of the invention are pointed out in particular in the appended claims. The invention itself, both as to structure and operation, together with additional objects and advantages thereof,

will be ,best understood from the following detailed description of one embodiment thereof when read in conjunction with the accompanying drawings, in which:

Figure 1 is a front elevational view of a multipole circuit breaker embodying the features of the invention; I

Fig. 2 is a side elevational view, partly in section, of the circuit breaker shown in Fig. 1;

Fig. 3 is a sectional view on an enlarged scale of one of the pole unit operating mechanisms, and Fig. 4 is an enlarged fragmentary view, partly in section, of the lower portion of-the breaker showing the master air relay valve and two of the blast valve operating means.

' The features of the present invention are illustrated as applied to a circuit breaker'of the same general construction as that 'disclosed'in the copending application of LB. Ludwig,'B.-P. Baker, and J. M. Cumming, Serial No. 437,010, filed March 31, 1942, and assigned to the assignee of the present invention. I

Referring to Fig. -1 of the drawings, the three pole circuit breaker. has three separate and mechanically independent circuit interrupting pole units 9 which are mounted in spaced relation on a structural supporting frame I The three pole units are of identical construction, and each unit comprises three hollow supporting insulators |3, -|5 and I1 secured to the frame in triangularly spaced relation and rising vertically therefrom. Supported on'the upper end of the insulators is a casing IQ for housing the contact operating mechanism more clearly shown in Fig. 3; The casing l9 supports a hollow insulator 2| which, in turn, supports a circuit interrupting element 23. A hollow insulator 25 extends upwardly from the element 23 and has a metallic terminal cap 21 secured on its upper end. A stationary contact member 29 (Figs. 1 and 2) extends downwardly from the terminal cap 21 into the circuit interrupting element 23.- A movable contact member 3| coacts with the stationary contact member 2-9 and extends downwardly through the element 23 and through the hollow insulator 2|. The lower end of the contact member 3| extends into the casing I 9 and is connected to an operating piston of the operating means as shown in Fig. 3. The movable contact member 3| is electrically connected by means of a resilient multipole contact finger assembly 33 (Fig. 3) and through the operatingcylinder casting to a terminal 35 (Fig. 2) which is secured to a projection on the lower end of the cylinder casting and which projects outwardly from the casing l9.

Extinction of arcs drawn by the movable contact member 3| upon interruption of the circuit is accomplishedby a blast of compressed gas or air directed to an arc-extinguishing structure of the fluid blast type which may be of the form disclosed in the copending application of L. R. Ludwig and B. P. Baker, Serial No. 373,856, filed January 1, 1941, U. S. Patent 2,313,159, issued March 9, 1943, and assigned to the assignee of the present invention. Since the present invention s ot c ncerned it t e arcxtin u shing unit structure per se, it is believed that the general designation of the are-extinguishing unit 31 (Fig. '2) located in the interrupting element 23 and which is supplied with a blast of compressed air, wlllbe sufilcient for the purpose at hand. Fluid under pressure, in this illSllallQQ QQOIII- P d air, for xti shin he arts n also for thecofntact operating mechanisms, is '5 .11 in a common reservoir or' tank 39 mounted within the frame Compressed air is stored and maintained at a predetermined pressure in the tank 39 by a suitable motor driven compressor unit (not shown).

Each movable contact member 3| is operated to opened and closed circuit position by an individual compressed air operating mechanism comprising a; double-acting piston 4| (Fig. 3) movable vertically in a cylinder 43 provided in a metal casting 45, there being an individual cylinder casting 45 and compressed air operating piston 4| for each of the three movable contact members 3|. Each contact operating mechanism is mounted within its corresponding casing l9, and the three operating pistons and their contact members are adapted to be operated simultaneously to open or closed position, by compressed air from the tank 39,, the flow of compressed air for opening and closing the three poles of the circuit breaker being controlled by a single opening valve mechanism 41 and a single closing valve mechanism 49 (Fig. 1).

Referring to Fig. 3, thecylindr casting 45 has an air blast tube| formed integral therewith communicating at its lower end with the passage through the hollow supporting insulator l3 (Fig. 2) and communicating at its upper end with the passage through the hollow insulator 2 I, this tube and the aforementioned passages through the insulators I3 and 2| forming a path for the blast of compressed air which is directed to the circuit interrupting element 23 during circuit opening operations.

v A lower cylinder head 53 is secured to the lower end-of the operating cylinder, and a shock absorbing assembly indicated generally at 55 is mounted in this cylinder head for absorbing the kinetic energy at the end of a circuit opening operation of the mechanism. A resilient shock absorbing bumper means 51 is mounted in the upper end of the operating cylinder for absorbing the kinetic energy of the moving parts at the end of circuit closing operation. This upper end of the, operating cylinder is closed by a cap .or head 59 which is threaded into the upper end of the cylinder and the head 59 is provided with an opening for slidably receiving the movable contact member 3| which is of tubular construction. The lower end of the tubular contact member 3| issecured to the operating piston 4| in .a central opening provided therein. The oper- "ating piston is also provided with a substantially square babbitted opening (not shown) in alignv ment with the tubular contact member for engaging a centrally disposed twisted square rod 6| which is rotatably mounted in a bearing 63 in the lower portion of the lower cylinder head 53. The twisted square rod extends throughout the entire length of the operating cylinder, the lower end thereof having a cylindrical portion engaging the bearing 63, and a crank arm 65 is rigidly secured to the lowermost end of the rod which projects downwardly fromthe bottom of the cylinder head 53. The operating piston 4| and thehollow tubular contact member 3| slide telescopically on the twisted square rod 6| as the operating piston is moved upwardly and downwardly in the operating cylinder, and this movement of the operating piston, due to the square opening therein and the twisted construction of.

the rod, causes the rod to be rotated through an angle in one direction when the piston is moved moved upwardly to closed circuit position. This movement of the rod G| is utilized to operate a conventional multipole auxiliary switch (not shown) through the agency of the crank 65 and a linkage 6T, 69, 1|, and 13.

An air \passage formed in the upper end of the cylinder casting leads to the upper end of the operating cylinder and is connected through a short section of pipe ll to the upper portion of an inlet and automatic dump valve assembly 19 secured to the side of the cylinder casting.

' An inlet port 8| of the valve assembly 19 is connected through a pipe 83 (Fig. 2) and the passage through the hollow insulator |5 to an opening air manifold pipe 85 (Fig. 1) common to the three lpole units of the circuit breaker. The compressed air for producing simultaneous opening operation of the movable contact members 3| is adapted to flow through the opening air manifold 85 and through the three hollow insulators l5 and pipes 83 to the upper ends of the three operating cylinders. The opening air manifold 85 is connected by a pipe 8? to the single opening Valve mechanism 41 which controls the simultaneous opening operation of all three poles of the circuit breaker. The single opening valve mechanism 41 is connected by a pipe 89 (Fig. 1) to the air reservoir tank 39.

An air passage 9| formed in the lower end of the cylinder casting 45 is connected through a pipe 93 to the lower section of the automatic valve assembly 19, and a closing air inlet port 95 of the valve device (9 is connected through a pipe 91 and the air passage through the hollow insulator H to a closing air manifold pipe 99 (Fig. 1) disposed within the frame H. lhe closing air manifold 99 is common to the three pole units. that is to say, it is connected through the passages of the three insulators l7 and pipes 91 to the lower end of the three contact operating cylinders. The closing air manifold 99 is connected by a pipe |0| to the single closing valve mechanism 49 which controls simultaneous closing op eration of the three contact members 3| of the circuit breaker. The valve mechanism 49 is connected by a pipe I03 to the air reservoir tank 39.

The opening valve mechanism 4i and the closing valve mechanism 49 are of the same construction as disclosed in the copending application of L. H. Ludwig, et al., Serial No. 431,394, filed February 18, 1942; and assigned to the assignee of the present invention; and only a brief description thereof will be given in this application as the details of construction of these valve mechanisms are not necessary to a complete understanding of the present invention.

Referring to Fig. 1, the opening valve mechanism 41 has a valve element H35 which is biased closed and which is caused to be opened by air pressure in the pipe 89 when the pilot valve of the mechanism is operated upon energization of a solenoid I01. Similarly, the closing valve mechanism 49 has a valve element H39 which is biased closed and which is caused to be opened by compressed air in the pipe 3'63 when the pilot valve of the mechanism is operated in response to energization of a solenoid HI associated with the valve.

When the single opening valve mechanism 41 is operated to open position, compressed air fiows from the tank 39 through the opening air manifold 85, through the three insulators l5, pipes 83, inlet ports8| of the valve devices 19 and pipes 1'! into the upper ends of each of the three operating cylinders 43 above the operating pistons 4|; The flow of compressed air to the ports 8| immediately moves the three slide valve elements of the valve devices 19 to their lower position, thereby connecting the lower ends of the main operating cylinders to atmosphere through exhaust ports H3. The compressed air flowing to fold 99 through the three hollow insulators II,

pipes 91, inlet ports 95 and pipes 93 to the lower end of the three operating cylinders 43. The flow of compressed air to the ports '95 causes the slide valve elements of the valve devices I9 to connect the upper ends of the three operating cylinders to atmosphere through the exhaust ports H5. The flow oi compressed air to the lower end of the operating cylinders drives the three pistons 4| simultaneously upwardly to their closed positions, thereby effecting closing of the three movable contact members 3i.

The construction of the circuit breaker as thus far described in detail above is substantially the same as that disclosed in the aforementioned copending application of L. R. Ludwig, B. P. Baker and J. M. Cumming Serial No. 437,010.

A separate air blast valve indicated generally at I I1 is provided for each of the three pole units of the circuit breaker. In accordance with the present invention, the three blast Valves II! are operated simultaneously by a compressed air operating system under the control of a single electro-pneumatically controlled air relay valve. Each blast valve Il'l includes a housing H3 (Fig. 4), the lower end of which is connected by a pipe I21 to the air reservoir tank 39. The upper end of the blast vlave housing H9 is connected. by a short section of pipe I23 to the passage of the hollow supporting insulator I3 of its corresponding pole unit. The valve element I25 within the blast valve housing is connected by means of a rock shaft 521 and a rod I28 to a blast valve operating piston I29 disposed in the valve operating cylinder Hit. A pair of concentrically disposed helical compression springs I33 mounted in the cylinder'IBI between the valve piston I29 and the head of the cylinder act to bias the blast valve element I25 to closed position and normally maintain the valve in closed position. Upward movement of the valve operating piston I29 effects opening of the blast valve.

The lower ends of the three blast valve operating cylinders I3l are connected to a manifold pipe I35 through which compressed air for simultaneously operating the three blast vlaves is adapted to flow tothe lower sides or" the valve operating pistons. The manifold pipe I35 is connected by a pipe I31 to the valve chamber of an electro-pneumatically controlled master air relay valve mechanism indicated generally at I39 (Fig. 4) The master'control valve I 39 is, in turn, con,-

nected by a" pipe I ti and the pipe 89 to the air rounding the valvestem- T e upper end ofthe Closing operation of the circuit breakspring engages the under side of a collar I41 secured to the top of the valve stem, and the lower end of the spring bears against the spider which supports the guide sleeve bearing for the valve stem. The valve element I43 is adapted to be operated to open position by an air piston I49 which is movably mounted in a small cylinder formed in the upper portion of the valve housing MI. The valve operating piston I49 is biased to its upper position shown in Fig. 4 by means of a helical compression spring I5 I. The valve piston I49 is adapted to be moved downwardly to effect openingcf the valve element I i-3, by the flow of compressed air through air passages I56 and I53 to the upper side of the piston I 33 upon opening of a pilot valve I55. The pilot valve I55 is 0perated to open position upon energization of a solenoid I5? and is returned to closed position upon deenergization of the solenoid. The valve housing I42 is provided with an exhaust passage I59 which connects the valve chamber to atmosphere when the valve mechanism and its operating piston M9 are returned to the normal position shown in Fig. 4. When the master valve is in its normal closed position, as shown'in Fig. 4, the exhaust passage I53 provides an exhaust for air in the lower portions of the three blast valve operating cylinders I3! below the blast valve operating pistons, thereby permitting the blast valves to be quickly returned to closed position immediately after the master control valve I39 is closed. The master valve operating piston I49 is provided with a skirt Ifil arranged to close the exhaust passage I59 when the piston M9 is moved downwardly to effect opening of the master valve element I43.

The pneumatic operating system for simultaneously operating the three blast valves has the advantage that it requires only a single master control valve and a single control eleotromagnet or solenoid for controlling operation of all of the blast valves of the circuit breaker. The arrangement assures that the blast valves will all operate simultaneously even though there is no mechanical tie between the valves, and the pneumatic system is faster in operation and more free from trouble than constructions which utilize a mechanical tie or an electrical tie between the blast valves.

The opening valve mechanism il is mechanically interlocked with the operating lever arm I59 (Fig. l) of the center pole blast valve II! by means of a lever E52 pivoted on the housing of the opening valve al and connected at one end to the opening valve element I05. The interlock includes a projection 55% on the arm I50 of the center pole blast valve which is disposed to block opening movement of the lever I52 and thereby prevent opening of the opening valve I I1 except when the center pole blast valve is operated to open position. The interlock thus serves to prevent opening of the opening valve mechanism 4'! if the blast valves become inoperative, i. e., fail to open for any reason.

The solenoid I5? of the master air relay valve and the solenoid Iil'l of the opening valve mechanism are adapted to be energized simultaneously tion of the solenoid ml of the opening valve mechanism 41 and the solenoid I 51 of the master air blast control valve I33. Opening of the valve ll causes compressed air to flow from the tank 39 to the upper ends of each of the three operating cylinders 43 and the compressed air drives the three contact operating pistons 4| simultaneously downwardly to open position, efiecting opening at the circuit breaker. The energization of the solenoid I51 of the master control valve I39 efiects opening of the :pilot valve I55, thereby admitting compressed air from the pipe I 4| through the passages I56 and I53 to the top of the valve operating piston I49. Piston I49 is driven downwardly by the compressed air and effects opening of the master valve element I43, whereupon compressed air flows from the pipe I4I into the manifold I35 to the lower sides of the three blast valve operating pistons I255. This flow of compressed air to the lower sides of the three blast valve operating pistons produces simultaneous upward movement of the three valve pistons, thereby effecting simultaneous opening of the three blast valves I25. The opening of the three blast valves I25 causes blasts of compressed air from the tank 39 to be directed to each of the three circuit interrupting elements 23 to blow out the arcs drawn by the three movable contact members 3|. Air blasts into the circuit interrupting elements 23 occur prior to the time that the movable contact members 3! separate from their stationary contacts 29 and the air blast is maintained until after the arcs have been extinguished. Upon deenergization of the master valve controlling'solenoid I51, the pilot valve I55 returns to closed position and the master valve I43 is returned to closed position by its biasing spring I45 when the valve operating piston I49 is reset to its upper position by the spring I5I. When the master valve I39 is thus returned to closed position, the supply of compressed air to the blast valve pistons l29 is shut oil and the three blast valves simultaneously are returned to closed position by their biasing springs I33.

Closing operation of the circuit breaker is initiated by the energization of the closing valve solenoid III. When the closing valve 49 opens, compressed air flows from the tank 39 into the closing air manifold 99 and through the same to the lower ends of the three contact operating cylinders 43. Compressed air simultaneously drives the three operating pistons i! upwardly to closed position, thereby effecting closing of all three movable contact members 3i into engagement with their stationary contacts. As soon as the closing operation. is completed, the solenoid III is deenergized and the closing valve is returned to closed position.

While the invention has been disclosed in accordance with the provisions of the patent statutes, it is to be understood that various changes in the structural details and arrangement of parts thereof may be made without departing from some of the essential features of the invention. It is desired, therefore, that the language of the appended claims be given the broadest reasonable interpretation permissible in the light of the prior art.

I claim as my invention:

1. A gas blast multipole circuit breaker comprising a plurality of separate circuit interrupting units each having a pair of separate contacts, operating means for simultaneously operating all of said pairsof contacts, a source of gas under pressure for supplying a blast of gas to each of said units to extinguish the arcs formed on sepa ration of said contacts, a separate blast valve associated with each of said units for controlling the flow of blast gas from said source to said unit, and a gas pressure operating system for said blast valves, said operating system having a single master control valve for simultaneously controlling operation of said plurality of blast valves.

2. A multipole compressed air circuit breaker comprising a plurality of separate circuit interrupting units each having a pair of separable contacts, operating means for simultaneously operating said contacts, a source of compressed air, air conduits connecting said units to said source of compressed air for conducting blasts of compressed air from said source to said contacts to extinguish arcs formed upon separation of said contacts, a separate air blast valve for each unit for controlling the flow of blast air to said unit, a compressed air operating system for said blast valves including a single master control valve for controlling the operation of said blast valves, and an electromagnet for controlling said master valve.

3. A multipole compressed air circuit breaker comprising a plurality of separate circuit interrupting units, each having a pair of separable contacts, operating means for said contacts, a source of compressed air, blast air conduits connecting said units to said source of compressed air for conducting blasts of compressed air from said source to said contacts to extinguish arcs formed upon separation of said contacts, a separate air blast valve for each unit for controlling the flow of blast air to said unit, compressed air operating means for said blast valve comprising a master relay valve for simultaneously controlling the operation of said plurality of blast valves, and an electropneumatic pilot valve for controlling said relay valve.

4. A multipole compressed air circuit breaker comprising a plurality of mechanically independent and separate circuit interrupting units each having a pair of separable contacts, operating means for simultaneously operating said pairs of contacts, a source of compressed air, relatively short air conduits of equal length directly connecting said units to said source of compressed air for conducting blasts of compressed air to said contacts to extinguish arcs formed upon separation of said contacts, a separate air blast valve associated with each unit for controlling the flow of blast air to said unit, a compressed air system for operating said blast valves comprising a separate air pressure actuated piston for each valve for opening said valve, and a master air re lay valve for simultaneously controlling the operation of said blast valves.

5. A multipole compressed air circuit breaker comprising a plurality of separate and mechanically independent circuit interrupting units each having a pair of separable contacts, compressed air operating means for simultaneously operat ing said pairs of contacts, a source of compressed air, relatively short air blast conduits of equal length directly connecting said units to said source of compressed air for conducting blasts of compressed air to said contacts to extinguish arcs formed upon separation of said contacts, a separate air blast valve for each unit for controlling the flow of blast air to said unit, a compressed air operating system for said valves comprising a separate air piston for each valve operable to open said valve, a common air conduit communicating with said pistons, and a master air control valve for controlling the flow of compressed air to said common air conduit for simultaneously controlling the operation of said plurality of blast vlaves.

6. A multiple compressed air circuit breaker comprising a plurality of separate and mechanically independent circuit interrupting units each having a pair of separable contacts, compressed air operating means for simultaneously operating said pairs of contacts, a source of compressed air, air blast conduits connecting said units to said source of compressed air for conducting blasts of compressed air from said source to said contacts for extinguishing the arcs formed upon separation of said contacts, a separate air blast valve for each unit for controlling the flow of blast air to said unit, a compressed air operating system for said valves comprising an individual cylinder and piston for operating each valve, a common air conduit connected to all of said valve operating cylinders, a pneumatically operated master air relay valve for controlling the flow of compressed air to said common air conduit for simultaneously controlling operation of said blast valves, and an electromagnetically controlled pilot valve for controlling operation of said master valve.

HOWARD M. WILCOX.

D l S C L A l M E l? 2,340,095.-H0ward M. Wilcox, Wilkinsburg, Pa. FLUID BLAST CIRCUIT BREAKER. Patent dated January 25, 1944. Disclaimef filed August 29, 1944, by the assignee, Westinghouse Electric c Manufacturing Company. Hereby enters this disclaimer to claims 1, 2, and 3 of said patent.

[Official Gazette October 3, 1944.]

D i S C L A l M E I? 2,340,095.H0ward M. Wilcox, Wilkinsburg, Pa. FLUID BLAST CIRCUIT BREAKER. Patent dated January 25, 1944. Disclaimef filed August 29, 1944, by the assignee, Westinghouse Eiectr'ic d Manufacim-ing Company. Hereby enters this disclaimer to claims 1, 2, and 3 of said patent.

[Official Gazette October 3, 1944.]

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