US2708700A - Presssure gas operated electrical circuit breaker device - Google Patents

Description

H. THOMMEN 2708700 PRESSURE GAS OPERATED ELECTRICAL CIRCUIT BREAKER DEVICE May 17, 1955 2 sheets-sheet 1 Filed Jan. 22, 1954 mun-m J m m w M ATTORNEYS PRESSURE GAS OPERATED ELECTRICAL CIRCUIT BREAKER DEVICE Filed Jan. 22, 1954 2 Sheets-Sheet 2 Q i R g m q u t 2' 1" w H QTY! q,

M N l'lll'll w i \K I E I 1 I INVENTOR ./.7/v.s WON/WAT,

BY PM ,JWA 4w ATTORNEYS nite titates Patent Oiiice Paton-tool lv'iiay l7, 1%55 arcane PREgSUkE GAS @FERATED ELECTRICAL CIRQUET BREAKER DEVICE Hans Tllominen, Baden, Switzerland, assignor to Aktienges-ellschaft Brown, lloveri & Cie, Baden, Switzerland, a innit-stock company Application Sanitary 22, 195%, Serial No. 495,548

Claims priority, application Switzerland Jlannary 24, B53

2 Claims. (Cl. Mi -4&8)

The present invention relates in general to circuit breaker systems and in particular to those utilizing a main, pressure gas operated switch for extinguishing the load current, and an auxiliary switch, also pressure gas operated, whose contacts are connected in series with the contacts of the main switch, for insulating the load from the power supply point, the contacts of the auxiliary switch being opened after opening of the contacts of the main switch. It is known to control both switches by means of electro-pneumatic valves in such manner that when switching off, interruption of power is effected by opening of the contacts of the main switch and this is followed by opening of the contacts of the auxiliary switch. The contacts of the main switch then reclose automatically after the arc gap area of those contacts has been deionized, and the load can then be reconnected to the power source by closure of the contacts of the auxiliary switch.

Switching systems as described above are well suited for diminishing the number of power failures in power plants which, for example, may be caused by short-circuiting arcs. in the latter case, dependent upon a change in electrical magnitude, the load is reconnected to the power source at least once again before being finally disconnected by the auxiliary switch. Moreover, the switching out systems are so constructed that the liow of pressure gas to the contacts of the main switch, and which is utilized to open the contacts, is cut off after the contacts open in order to diminish the consumption of pressure gas. it is also known to provide impedances connected in parallel with the contacts of the main switch in order to diminish the residual current which must be interrupted by the contacts of the auxiliary, series connected switch, and in order to achieve an approximately uniform distribution of voltage over all contacts of the main, power switch. Furthermore, it is known to construct the main switch with a plurality of sets of contacts arranged in series and with impedances connected in parallel with each set of contacts, and to close oil the passages for the escape of pressure gas after the contacts have been separated, thereby maintaining the pressure of the gas in the chamber containing the contacts and increasing the voltage insulation protection provided by the auxiliary switch connected in series with the main switch. However with switching arrangements of this kind, pressure gas is conducted to the contacts of both the main and auxiliary switches over paths which are in part common to both switches and hence it is necessary to provide both switches with means for blocking off the escape of pressure gas from the chambers housing the contacts thereof. This not only results in a larger than desired consumption of the pressure gas but also involves an increase in manufacturing costs because of the many gasket points involved. Moreover the large number of gasket points increase correspondingly, the chances for plant failures at such points.

The present invention is directed to an improved switching arrangement comprising main and auxiliary switches connected in series for power interruption and voltage insulation, respectively, each of which switches includes one switching point constituted by at least one moved, selfclosing nozzle contact, in which the switching points of both switches are actuated and blown upon by the pressure gas, and in which the above described deficiencies are eliminated. The invention is characterized by a control for the pressure gas such that in a switching oil operation, on the one hand, pressure gas escapes to the exterior of the chamber housing the contacts of the main switch after blowing upon, separating and tie-ionizing the contact points, and that, on the other hand, pressure gas is conducted to the switching points of the auxiliary switch, for the insulation of the voltage, along a path which is completely separate from and independent of that leading to the contacts of the main switch. The contacts or" the auxiliary switch are thereby blown open and gas pressure is maintained on those contacts until it is desired to reconnect the load.

Various embodiments of the invention are shown in the accompanying drawings wherein:

Fig. 1 is a side view partly in elevation and mostly in entral longitudinal section of an embodiment consisting of a single, main switch and a single auxiliary switch;

Fig. 2 is a view in side elevation showing an embodiment comprising two main switch sections arranged vertically in parallel, spaced relation and an auxiliary switch individual to each main switch and connected in series therewith, the auxiliary switches being series connected and arranged as the arms of a T, normal to and extending between the two main switch sections; and

Fi 3 is an embodiment shown partly in side elevation and partly in central longitudinal section illustrating essentially a modification of the arrangement shown in Fig. 2.

With reference now to the drawings, and particularly Fig. l, the switching system is comprised of an elongated tank 1 which may be mounted on wheels 2 if desired for ease in transport. This tanl: is charged with the pressure gas used for actuating (opening or separating) the contacts of the main and auxiliary switches. Upstanding upon tank 1 at the left side thereof is a valve assembly 3 terminating in a cylindrical flange 3a upon which upstands an insulator column 4 having a longitudinal bore 4a extending therethrough.

Upstanding upon the top of column 4 is the main switch assembly e. The latter is comprised of a lower tubular electrically conductive member 6a secured by a bottom flange thereof to the top of insulator column 4, a hollow insulator column 611, upstanding upon and secured to an upper flange of member Ga, which forms chamber for the switch contacts, an electrically conductive, hollow cylinder 6c forming a top closure for the switch contact chamber, an electrically conductive piston 6d slidable in the cylinder 6c, a nozzle contact 62 depending from the piston 6d and movable with the latter, a fixed contact of cooperative with the nozzle contact 6e, and which is secured to the tubular member 6a,

a spring 6g in the cylinder (in which urges piston 6d and hence also nozzle contact 62 into engagement with the fixed contact 6]", a. top opening 611 in cylinder 60 for venting pressure gas from switch chamber 6b when the contacts are separated, and a cap 61' over and electrically connected to cylinder 6c. The contact axis lies along the axis of the hollow insulator column 4.

The valve assembly 3 includes a. movable valve member provided with a head 31) at one end adapted to seat upon and close off communication between tank 1 and a passageway 3c leadins through the valve into the lower end of the bore 4a in insulator column 4. At the opposite end of this valve member is a piston 3d operating in a cylinder 3e against a loading spring 3;. Control pressure gas entering cylinder 35 through a conduit 7 from a control mechanism 3, urges piston 3d to move "13d into engagement with the fixed contact 13s.

against the loading spring 3f and hence move valve head 3]) otf its seat. When the gas pressure on piston 3d is released, the loading spring 3 causes valve head 3b to reseat itself.

Upstanding upon tank 1 at the right side thereof is a second valve assembly terminating in a cylindrical flange 10a upon which upstands an insulator column 11 having a longitudinal bore 11:; extending therethrough.

A hollow, 90 elbow 12 is secured at one end by a flange thereon to the upper end of insulator column 11. Between the other flanged end of the elbow and the insulator column 4 and main switch assembly 6 is arranged the auxiliary series switch assembly 13. The latter is comprised of a horizontally disposed hollow insulator 13a forming a chamber for the auxiliary switch contacts, one end of the insulator being secured to elbow 12. Extending from the opposite end of insulator 13a is an electrically conductive cylinder 13b forming an end closure for the auxiliary switch contact chamber, an electrically conductive piston 13c slidable in cylinder 13b, a nozzle contact 13d secured to piston 13c and movable with the latter, a fixed contact 136 cooperative with nozzle contact 13d, and which is secured to and extends through elbow 12, and a spring 13, in the cylinder 13b which urges piston 13c and hence also nozzle contact It is thus seen that the contact axis of the auxiliary switch is normal to the contact axis of the main switch assembly. 6.

Associated with the chamber 13a for the auxiliary switch contacts 13d, Be is an outlet valve assembly 14 through which pressure gas is exhausted from chamber 13a to atmosphere following separation of these contacts, the valve reclosing automatically shortly after the contacts have separated. The particular valve construction illustrated to function in this manner includes a 'cylinder 14a having an opening 14b through the wall thereof to atmosphere, a combined piston and valve head 14c operating in such cylinder and a spring 14d which loads the piston or valve head He in such direction as to seat against and close oi the valve outlet 14a and hence outlet 14b also from chamber 13b. Valve head 140 includes a small opening 14 which enables the pressure of the gas to be equalized on opposite sides of the head shortly after the initial opening operation of contacts 13d, He thus permitting the valve to reclose by the force of the loading spring 14d.

The valve assembly 10 at the lower end of insulator column it includes a two position valve member 1% having a piston 100 on one end operating in cylinder 10d and a valve head We on the opposite end. In one position of the valve member 1%, the position shown in the drawing, head 1% seats against and closes off the mouth of an outlet 10f leading from the interior of tank 1 into the bore 11a of insulator column 11. This is made possible by the fact that the interior of cylinder 19d communicates with outiet 10) and the area of piston 19c is larger than that exposed to the pressure of the gas in outlet ltlf at the underside of valve head 1% thus establishing a pressure gas derived force differential in the direction to seat the head 10a and close off outlet 10 This is the position occupied by the valve when the contacts of the auxiliary switch 13 are closed.

In the other position of the valve member 10!), valve head ltle seats against and closes off an outlet 10g which otherwise maintains the bore 11a of column 11, and hence also the chamber 13a for the auxiliary switch contacts 13:5, 15:2, in communication with the atmosphere. The valve member liib is actuated from the position shown to the position closing off outlet 10g, by pressure air delivered via conduit 15 from tank 1 via the control mechanism 8 into the cylinder ltld at the side of piston 10c opposite the side to which the gas pressure in outlet 10) is applied, thereby applying a counter pressure sufiicient to reverse the direction of the 4 force differential acting on the valve member 1G1). Thus as the valve member 1% is actuated, it places the chambcr 13a for the auxiliary switch contacts 13d, 13a in communication with the interior of tank 1 and simultaneously closes 01f the exhaust or vent 19g from chamber 13a to atmosphere, and vice versa.

Operation Operation of the various elements in the switch organization of Fig. 1 occur in the following sequence. With the load connected through the two switches in series, the elements occupy the positions shown in the drawing. The electrical circuit from the load through the two switches can be traced from terminal 16 at the cap 61 of main switch assembly 6, through the wall of cylinder 6c, piston 6d, nozzle contact 6e, fixed contact 6 tubular member 6a, rigid conductive rod 18 extending from member 6a to cylinder 13b of the auxiliary switch assembly 13 and which helps to support that end of the assembly, piston 13c, nozzle contact 13d and fixed contact 132 to the other terminal 17.

Assuming it is now desired to open the circuit, a signal current is applied to an electro-controlled pneumatic valve in control mechanism 8, which is conventional and therefore not illustrated, and pressure gas such as compressed air is admitted from tank 1 through conduit 7 into valve cylinder 3e causing the valve head 3b to unseat. Pressure gas then flows from tank 1 through the valve passageway 3c up through the bore 4a in column 4 and through the tubular member 6a into chamber 61). Pressure of the gas applied to piston 6:! moves the latter and hence also the nozzle contact 62 upward to separate it from fixed contact 6]. Pressure gas then flows upward through the nozzle contact, blowing upon the are, extinguishing it and de-ionizing the switching point, and the gas then discharges to atmosphere through the end opening 611 in cylinder 60. The main switch assembly 6 is thus charged with pressure gas only briefly. Hence no self-closing blocking valves need be associated with the switch contact chamber 6b and the cost of the construction is decreased accordingly.

Control current applied to another electro-controlled pneumatic valve in the control mechanism 8 effects flow of pressure gas through conduit 15 to valve 10 causing the valve head ltle to unseat and close off air vent outlet 16g. Pressure gas then flows from tank 1 through valve outlet 10 into and through the bore 11a in column 11 into the auxiliary switch chamber 1310. Pressure of the gas applied to the junction of nozzle contact 13d and fixed contact 1342 causes movement of the nozzle contact to the left to separate it from fixed contact 132. Pressure gas then flows through the nozzle and is applied to piston 13c which effects further separation of the contacts, and the gas pressure then opens valve 14 and discharges through valve 14 to the atmosphere, the valve 14 then reclosing automatically, in the manner previously described, to shut off the flow of pressure gas and maintain the gas pressure against piston 13c, thus holding the nozzle contact 13d away from its fixed contact 13s. Valve 3 then recloses shutting off the flow of pressure gas to the main switch 6 and the contacts 66, 6 thereof reclose. The load circuit however remains open at the contacts 13d, 13a of the auxiliary switch 13 which are connected in series with the contacts 62, 6 of the main switch 6. To reclose the load circuit it is thus only necessary to cut oil the flow of pressure gas through conduit 15 to valve cylinder 10d whereupon valve head 16a will be reseated to close off outlet 10f-and reopen the outlet 10 thus permitting the gas under pressure in chamber 13a to exhaust to atmosphere which releases the pressure on valve piston 13c and permits spring 13 to move this piston and hence nozzle contact 13d back into engagement with the fixed contact Be. This completes the series circuit through the two switches 6 and 13.

In the embodiment of the invention illustrated in Fig. 2, which makes for a very sturdy construction, the main switch assembly is comprised of two series connected sections 6' arranged in upstanding spaced relation on hollow insulator columns 4 which upstand at the opposite ends of the compressed gas supply tank 1'. The construction of each main switch assembly 6 is similar to switch 6 in Fig. 1 except that a plurality of series connected sets of nozzle and fixed contacts are utilized to divide the load current, and each set of contacts is bridged i. e. parallel by an impedance 20 illustrated as resistances (although they could be capacitances) which, as known, serve to distribute the voltage more uniformly over the sets of switch contacts. Valves 3 at the foot of each column 4 are connected via conduits 7' to a control mechanism 8 similar to mechanism 8 of Fig. l and operate in the same manner as valve 3 in the Fig. i embodiment. Between the insulator columns 4' is another hollow column 11' upstanding upon tank 1' and having a,valve 10 at the lower end thereof corresponding in construction and function to valve 10 of Fig. 1. Extending horizontally at the top of column 11' and to each side thereof is a series or auxiliary switch section 13' each similar in construction and function to switch 13 in Fig. 1, the two switch sections 13' being connected in series with and between the two series connected switches 6. Operation is basically the same as in Fig. 1. When breaking the load current, the contacts in the two main switch sections 6 are separated temporarily by admitting pressure gas through valve 3, the contacts of the auxiliary switch sections 13' are then separated by admitting gas through valve 10' to break the residual current carried by the impedance elements 20. The contacts of the main switch section 6 then reclose, and the contactsof the auxiliary switch sections 13 are maintained open by the continued application of pressure gas thereto and the automatic reclosing of outlet valves 14', which correspond in construction and function to valve 14 in Fig. 1, shuts off the flow of pressure gas to the auxiliary switch sections after their contacts have been opened. To reclose the circuit to the load it is only necessary to vent the contact chambers of switch sections 13; to atmosphere by actuating valve 10 to its other position.

The embodiment shown in Fig. 3 is basically similar to that shown in Fig. 2 in that the switching device for interrupting the main load current is divided into two series connected sections 6 and the two auxiliary switches 13" are connected in series with and between the two switches 6". However unlike the Fig. 2 embodiment wherein the contacts of the auxiliary switch sections 13 are subjected to pressure gas only when those contacts are about to be opened, the contacts of the auxiliary switch sections 13" are always subject to the pressure of the gas. To make this possible, it will be observed that hollow column 11" is in continuous communication with the pressure gas tank 1" (there being no valve corresponding to valve 10') thereby always being present in contact chamber 13a" and applying the pressure to the junction of the nozzle and fixed contacts 13d", 132". These contacts do not however separate but remain closed since provision is made for applying a counter, pressure gas derived, force, in addition to that provided by spring 13f", to the opposite side of the piston 13c". This is accomplished by the addition of two other hollow insulator columns 21 upstanding upon and in communication through valve 22 at the lower ends with tank 1" and being also in communication at the opposite ends with the cylinder 13b" of each auxiliary switch section 13" at the side of the piston 130 on which the loading spring 131" is located. The vent opening 141) of outlet valve 14" leads from cylinder 14a" to the interior of insulator column 21 and downwardly therethrough and through valve 22 (which is of the same construction as valve 10 in the Fig. 1 embodiment) to atmosphere when the latter is in the position shown for valve 10 in the Fig. 1 embodiment. In the other position of each valve 22, the interior of each column 21 is in communication with tank 1" and the opening to atmosphere in each valve 22 is cut off. Under this latter condition pressure of the gas applied against the spring side of piston 13c establishes the necessary force differential to maintain the nozzle and fixed contacts 13d, 13s" of each switch section 13" closed.

To open the load circuit, valves 3" are actuated as a result of how of pressure gas through conduits 7" in response to a signal current applied to control mechanism 8 to thus cause the contacts of the main switch sections to separate. Thereafter, valves 22 are actuated to thus vent each cylinder 13b" at the spring side of piston 130" to atmosphere whereupon the pressure of the gas in each switch contact chamber 13a is then able to separate contacts 13d", 13a of each of the auxiliary switch sections 13" thus breaking the currents flowing through impedances 20'. The related arcs are extinguished by passage of gas which bathes the contacts, and the spent gases push each piston 14c" from its seat and fiow through each valve port 14b" into each column 21 and out of the latter to atmosphere. Each valve piston 14c" reseats after a brief period, closing off the fiow of pressure gas and the contacts 13d", 13a" of each switch section 13 are maintained in the open position surrounded by the pressure gas. To reclose the circuit through the switches 6" and 13", it is merely necessary to move valve 3" to their other position wherein the lower end of each insulator column 21 is cut off from atmosphere and again communicates with the interior of tank 1".

In conclusion it is to be understood that while the embodiments described and shown are preferred, various modifications thereof and of the specific construction of the various component parts may be effected without departing from the spirit and scope of the invention as defined in the appended claims.

I claim:

1. In a circuit breaker system for breaking a load current and insulating the load from its power source, the combination comprising main and auxiliary switches of the pressure gas operated type connected in series, said main switch being comprised of two switch sections each being constituted by at least a pair of pressure gas operated relative movable contacts one of which is a nozzle contact through which the pressure gas flows upon separation of the contacts, a tank constituting the source of said pressure gas, a hollow insulator column individual to and upstanding upon said tank for the support of each switch section, each said column establishing a passageway for the flow of pressure gas from said tank to the switch section, said auxiliary switch being also comprised of two switch sections each being constituted by a pair of pressure operated relatively movable contacts one of which is a nozzle contact through which pressure gas flows upon separation of the contacts, hollow insulators enclosing the two sections of said auxiliary switch and extending between the insulator columns supporting the sections of said main switch, hollow insulator column means upstanding upon said tank and supporting one end of each of said insulators enclosing the two sections of said auxiliary switch, said ends of last said insulators being in continuous communication with the pressure gas in said tank through said hollow insulator means, other hollow insulator column means upstanding upon said tank and supporting and being in communication with the opposite ends of said insulators enclosing the two sections of said auxiliary switch to establish a counter pressure on the contacts of the sections of said auxiliary switch preventing separation of said contacts, first valve means arranged in said other hollow insulator column means for controlling flow of pressure gas from said tank to the sections of said auxiliary switch, said valve means in one 7 position thereof venting said other hollow insulator column means to atmosphere to thereby establish a pressure differential on the contacts of the sections of said auxiliary switch to effect opening thereof, and in the other position thereof closing'ofi said vent to atmosphere and placingsaid other hollow insulator means in communication with the interior of said tank, and second valve means in each of said insulator columns supporting the sections of said main switch for controlling the flow of pressure gas from said tank to the contacts of said main switch.

2. A circuit breaker system as defined in claim 1 wherein said first valve means associated with said other hollow insulator column means are arranged at the lower ends thereof adjacent said tank. V I

References Cited in the file of this patent UNITED STATES PATENTS 2,561,192 Forwald July 17, 1951 2,592,079 Thornmen et a1 Apr. 3, 1952 FOREIGN PATENTS 487,391 Great Britain of 1938 581,236

Great Britain Oct. 4, l94' 6

Images