US3819890A

US3819890A - Explosion circuit breaker

Info

Publication number: US3819890A
Application number: US00254679A
Authority: US
Inventors: G Mikhailu; N Skugorova; V Semchenko; V Biteryakov; K Kozorezov
Original assignee: Individual
Current assignee: Individual
Priority date: 1971-05-25
Filing date: 1972-05-18
Publication date: 1974-06-25
Anticipated expiration: 1991-06-25
Also published as: GB1394067A; DE2224252A1; IT960794B; SU418141A1; FR2139093A1; BE783921A; NL7206855A; JPS4910372A

Abstract

An explosion type circuit breaker incorporating a hollow current-carrying bus containing an explosive charge and detonator characterized in that the current-carrying bus is provided with dielectric sheathings covering outer and inner surfaces of the hollow current-carrying bus, the dielectric sheathing covering the inner surface of the current-carrying bus having an annular groove and the explosive charge having an annular cumulative recess lined with a dielectric and facing the above-mentioned annular groove of the dielectric sheathing.

Description

United States Patent [191 Kozorezov et al EXPLOSION CIRCUIT BREAKER [76] Inventors: Konstantin lsaakovich Kozorezov, Universitetsky prospekt, 21, korp. l, kv. 29; Vitaly Vasilievich Semchenko, ulitsa 26 Bakinskikh Komissarov, 8, korp. 3, kv. 32; Viktor Vasilievich Biteryakov, ulitsa Vvedenskogo, 7, kv. 98; Georgy Ivanovich Mikhailu, ulitsa Volgina, 23, korpus l, kv. 52; Nine! Fedorovna Skugorova, ulitsa Bolshaya Cheremushkinskaya, 57, korp. 30, kv. 23, all of Moscow, U.S.S.R.

[22] Filed: May 18, 1972 [211 Appl. No.: 254,679

[ June 25, 1974 [58] Field of Search ZOO/61.08

[56] References Cited UNITED STATES PATENTS 3,1 l7 l94 1/1964 Stresau. Jr. ZOO/61.08

Primary ExaminerJames R. Scott Attorney, Agent, or FirmHolman & Stern [5 7] ABSTRACT An explosion type circuit breaker incorporating a hollow current-carrying bus containing an explosive charge and detonator characterized in that the current-carrying bus is provided with dielectric sheathings covering outer and inner surfaces of the hollow current-carrying bus, the dielectric sheathing covering the inner surface of the current-carrying bus having an annular groove and the explosive charge having an annular cumulative recess lined with a dielectric and facing the above-mentioned annular groove of the dielectric sheathing.

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sum 3 0F 3 V/// //////////g W EXPLOSION CIRCUIT BREAKER BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to the field of electrical engineering and more particularly to explosion circuit breakers which provide a means for quick circuit interruption and breaking of heavy-current and high-voltage circuits.

2. Description of Prior Art In view of the general trend in present-day science and engineering technology to raise the unit capacity of electric power and electrophysical installations such as generator sets, capacitive and inductive energy accumulators, installations for thermonuclear fusion, etc the problem of protection of these large installations arises during emergency conditions, also, switching of highpower and extra-high-power circuits is being given great consideration.

Certain difficulties have to be overcome in solving the above problems as they call for rapid interruption of high-voltage and heavy-current circuits.

Solution of these problems by conventional methods has led to the development of circuit breakers with various types of arc quenching means (air-blast, magnetic blast), and insulating fillings such as in, for example, oil-filled circuit breakers. These circuit breakers rely for their operation on mechanical interruption of the electric circuit and extinction of the are between the separating contacts by cooling and lengthening the arc gap. However, the operating time of these circuit breakers amounts to several milliseconds since the arc is lengthened at a rate of about a few tens of metres per second.

Known in the present state of the art are circuit breakers wherein charges of explosives are used to increase the speed of interruption of the electric circuit. Such circuit breakers comprise a hollow current carrying conductor, preferably of tubular shape, containing an explosive charge and a detonator. The hollow conductor has longitudinal slits and transverse notches and seams within the narrowed middle or end part of the conductor. On explosion of the charge, the conductor bursts and spreads out into a kind of rosetter. while the hollow ends of the conductor serve as nozzles for extinguishing the breaking current are by jets of the products of explosion.

In practice, however, the operating time of this device cannot be made shorter than 30 to 40 microseconds. This is due mainly to the two following factors: firstly the speed of interruption of the electric circuit does not exceed l to 2 mm per microsecond (increase of the speed up to 3 mm per microsecond calls for a considerable increase of the explosive charge), secondly the arc is quenched by explosion products which are of relatively low dielectric strength (the products of the explosion expand and their pressure drops with the sixth power of the radius of space occupied by these products).

SUMMARY OF THE INVENTION A primary object of the present invention is to eliminate the above-mentioned disadvantages.

It is a further object of the present invention to provide an explosion circuit breaker having an operating time of l to 5 microseconds employing a limited explosive charge.

These objects are accomplished by the present circuit breaker incorporating a hollow current-carrying bus containing an explosive charge and detonator; in accordance with the disclosed invention, the hollow current-carrying bus is provided with dielectric sheathings on its inner and outer surfaces and the dielectric sheathing on the inner surface of the currentcarrying bus has an annular groove and the explosive charge has an annular cumulative recess lined with a dielectric and facing the above-mentioned annular groove of the dielectric sheathing.

A second version of the present invention consists in that the dielectric sheathing covering the outer surface of the above-mentioned current-carrying bus has an annular groove formed opposite the annular groove of the dielectric sheathing which covers the inner surface of the above-mentioned current-carrying bus.

BRIEF DESCRIPTION OF THE DRAWING The above and other objects, advantages and features of the present invention will be more fully understood from the following detailed description of its embodiments considered in connection with the accompanying drawings, in which:

FIG. 1 illustrates a cross-sectional view of an explosion type circuit breaker constructed in accordance with the present invention, this Figure showing the position of the circuit breaker components before the explosion;

FIG. 2 is a cross-sectional view of the embodiment 0 FIG. 1 showing the position of the circuit breaker components during the explosion;

FIG. 3 is a cross-sectional view of another embodiment of the explosion-type circuit breaker in accordance with the teachings of the present invention, this Figure depicting the position of the circuit breaker components before the explosion;

FIG. 4 is a cross-sectional view of the embodiment of the invention of FIG. 3, depicting the position of the circuit breaker components during the explosion; and

FIG. 5 is a cross-sectional view of the embodiment of the invention depicted in FIG. 1, this Figure illustrating the condition of the current bus following the explosion.

DESCRIPTION OF PREFERRED INVENTIVE EMBODIMENTS The explosion circuit breaker incorporates tips 1 (FIG. 1) in which the hollow current-carrying bus 2 of cylindrical shape is fixed. The outer surface of the current-carrying bus 2 is covered by a dielectric sheathing 3 made as a hollow cylinder. The inner surface of the current-carrying bus 2 is covered by an inner dielectric sheathing 4 made as a hollow cylinder. The sheathing 4 has an annular groove 5.

An explosive charge 6 and detonator 7 are arranged inside the hollow current-carrying bus 2. The explosive charge 6 is in the form of a disc the side surface of which has an annular convergent or concave recess lined with a dielectric 9. As will be appreciated by those skilled in this art, the assembly constituting members 6 through 9 can be mounted in any convenient and known manner within the current-carrying bus 2 having sheathing 3 through 4. One technique by which such mounting can be effected is by means of plugs having annular centering grooves in their ends, one of the plugs having a through center hole for the wires of the detonator 7. Such plugs are widely known in this field and constitute prior art. In that such plugs are not important for an understanding of the principles taught by the instant invention, no specific illustration of same has been shown.

The explosive charge 6 is positioned so that the annular recess 8 is opposite the annular groove of the inner dielectric sheathing 4.

The explosion circuit breaker operates in the following manner, and attention is directed to FIG. 2.

On receiving an external control signal, the detonator 7 and the explosive charge 6 operate in succession. After detonation of the explosive charge 6, the material of the lining 9 forms itself into a high-speed cumulative jet [0 and pestle 11. Both the cumulative je t l0 and the pestle 11 are in the form of discs moving radially with a speed of and 10 m per second, respectively. The thickness of the cumulative jet 10 depends on the shape of the recess 8, the thickness and density of the lining 9, the speed of detonation within the explosive charge 6 and is from 0.1 to 0.9 of the width of the cumulative recess.

In order to avoid energy losses of the dielectric cumulative jet I0 needed to rupture the inner dielectric sheathing 4, this sheathing is provided with the abovementioned annular groove 5.

After passing into the annular groove 5, the cumulative jet l0 strikes the current-carrying bus 2. As a result. the jet 10 turns around and forms a film 12. The current-carrying bus 2 splits by bursting on explosion and its parts are accelerated in the direction perpendicular to the direction of motion of the cumulative jet l0. Afterwards, the cumulative jet 10 goes farther into the body of the outer dielectric sheathing 3.

The shattering of the current carrying bus 2 occurs in the course of l to 5 microseconds since the speed of penetration of the jet amounts to about 5 mm per second.

The pressure developed at the point of contact of the dielectric cumulative jet I0 and the outer dielectric sheathing 3 attains hundreds of atmospheres and so the arc of the breaking current is intensively cooled and quenched.

Thus, the dielectric sheathing 3 sets up head for the cumulative jet l0 and contributes to the development of high pressure within the region of the interaction. Furthermore, the outer dielectric sheathing prevents breakdown along the surface of the destroyed currentcarrying bus 2. Electric breakdown along the inner surface of the current-carrying bus 2 is prevented by the inner dielectric sheathing 4 and the products of explosion of the explosive charge 6 which expand in the axial direction. The body of the dielectric cumulative jet 10, the film l2 and the pestle I] prevent breakdown between the ends of the destroyed current-carrying bus 2. Reference is made to FIG. 5 for an illustration of the bus after the explosion.

The construction of the explosion circuit breaker shown in FIG. 3 differs from that shown in FIG. 1 in that the dielectric sheathing 3 covering the outer surface of the current-carrying bus 2 is also provided with an annular groove 13 (FIG. 3).

The explosion circuit breaker shown in FIG. 3 oper ates in the same way as the explosion circuit breaker shown in FIG. 1, the only difference being that the section of the current-carrying bus 2 located between the

grooves

5 and 13 is sheared off and moves radially outward at a high speed radially away from the break. Reference is made to FIG. 4 in this respect.

The explosion circuit breaker described above may be used without the dielectric lining 9 of the recess 8 of the explosive charge 6. It should be noted, however, that employment of the above-mentioned dielectric lining greatly improves the efficiency of operation of the explosion circuit breaker.

Thus, the present invention allows the shortening of the operating time of the explosion circuit breaker down to a value of l to 5 microseconds, recudes the weight of the explosive charge and improves its dielectric strength.

What is claimed is:

1. An explosive type electric power circuit breaker comprising:

a hollow current-carrying tubular bus;

outer and inner dielectric sheathings disposed respectively on the outer and innersurfaces of said hollow current-carrying tubular bus;

an annular groove formed on the periphery of said inner dielectric sheathing;

an explosive charge disposed inside said hollow current-carrying tubular bus, said explosive charge being shaped so as to have an annular notch shaped recess positioned opposite said annular groove in said inner dielectric sheathing; and

a detonator means for igniting and exploding said explosive charge at a moment when the electric power circuit in said hollow current-carrying tubular bus is desired to be interrupted;

said recess of said explosive charge directing the explosive force towards said annular groove of said tubular bus such that said bus bursts along a circumferential region adjacent of said annular groove so as to cause swift interruption of the electric power circuit.

2. An explosive circuit breaker as claimed in claim 1, wherein said outer dielectric sheathing disposed along the outer suface of said hollow current-carrying tubular bus is provided with an annular groove positioned opposite the annular groove made in the said inner dielectric sheathing so as to facilitate a more effective interruption of the electric circuit.

3. An explosive circuit breaker as claimed in claim 1, wherein said annular notch-shaped recess is lined with a dielectric substance, whereby said dielectric lining serves to impinge violently against said currentcarrying tubular bus so as to facilitate a more effective repturing thereof,- when a circuit interruption is initiated by detonating said explosive charge.

Claims

1. An explosive type electric power circuit breaker comprising: a hollow current-carrying tubular bus; outeR and inner dielectric sheathings disposed respectively on the outer and inner surfaces of said hollow current-carrying tubular bus; an annular groove formed on the periphery of said inner dielectric sheathing; an explosive charge disposed inside said hollow current-carrying tubular bus, said explosive charge being shaped so as to have an annular notch-shaped recess positioned opposite said annular groove in said inner dielectric sheathing; and a detonator means for igniting and exploding said explosive charge at a moment when the electric power circuit in said hollow current-carrying tubular bus is desired to be interrupted; said recess of said explosive charge directing the explosive force towards said annular groove of said tubular bus such that said bus bursts along a circumferential region adjacent of said annular groove so as to cause swift interruption of the electric power circuit.

3. An explosive circuit breaker as claimed in claim 1, wherein said annular notch-shaped recess is lined with a dielectric substance, whereby said dielectric lining serves to impinge violently against said current-carrying tubular bus so as to facilitate a more effective repturing thereof, when a circuit interruption is initiated by detonating said explosive charge.