SU890478A1

SU890478A1 - Liquid-metal safery switch

Info

Publication number: SU890478A1
Application number: SU802889641A
Authority: SU
Inventors: Василий Андреевич Андреев; Евгений Васильевич Бондаренко; Юрий Степанович Крежевский; Александр Федорович Кузьмин; Олег Всеволодович Петинов; Геннадий Владимирович Уфаев
Original assignee: Ульяновский политехнический институт
Priority date: 1980-03-06
Filing date: 1980-03-06
Publication date: 1981-12-15

Description

(54) ЖИДКОМЕТАЛЛИЧЕСКИЙ ПРЕДОХРАНИТЕЛЬ(54) LIQUID METAL FUSE

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Изобретение относитс к электротехнике и может быть использовано дл защиты электрооборудовани от токов короткого замыкани и перегрузок.The invention relates to electrical engineering and can be used to protect electrical equipment from short-circuit currents and overloads.

Известны жидкометаллические предохранители , которые автоматически замыкают электрическую цепь через некоторое врем после охлаждени паров металла, из которого изготовлена вставка 1.Liquid metal fuses are known that automatically close an electrical circuit some time after cooling the metal vapor from which the insert 1 is made.

Недостатком указанного предохранител вл етс то, что при возникновении электрической сети устойчивого короткого замыкани жидкометаллический предохранитель производит многократное включение источника тока на существующее короткое замыкание , следовательно, указанный предохранитель может работать только в совокупности с другими коммутационными аппаратами .The disadvantage of this fuse is that when a stable short-circuit electrical network occurs, the liquid metal fuse repeatedly switches on the current source to an existing short circuit, therefore, the fuse can work only in conjunction with other switching devices.

Наиболее близким по технической сущности к изобретению вл етс жидкометаллический предохранитель, содержащий электроизол ционный корпус с контактными колпаками , жидкометаллическую плавкую вставку и демпфер, размещенный в одном из контактных колпаков 2.The closest in technical essence to the invention is a metal fuse containing an electrically insulating housing with contact caps, a liquid metal fuse insert and a damper located in one of the contact caps 2.

Недостатком известного устройства вл етс необходимость дополнительного аппарата дл отключени защищаемой цепи.A disadvantage of the known device is the need for an additional apparatus for disconnecting the protected circuit.

Цель изобретени - повыщение надёжности отключени защищаемой цепи.The purpose of the invention is to increase the reliability of the disconnection of the protected circuit.

Поставленна цель достигаетс тем, что жидкометаллический предохранитель снабжен электромагнитом и щтоком, установленным в контактном колпаке, где размещен демпфер, жидкометаллическа плавка вставка выполнена в виде нескольких параллельных капилл рных каналов, в качестве демпфера использован сильфон, а корь электромагнита через щток соединен с указанным демпфером.The goal is achieved by the fact that the liquid metal fuse is equipped with an electromagnet and a brush installed in the contact cap where the damper is located, the liquid metal melting insert is made in the form of several parallel capillary channels, the bellows is used as the damper, and the electromagnet measles are connected to the damper as a damper.

Кроме того, в жидкометаллическом предохранителе корпус электромагнита может 15 быть электрически изолирован от контактного колпака, а корь электрически изолирован от сильфона.In addition, in the liquid metal fuse, the body of the electromagnet can 15 be electrically isolated from the contact cap, and the measles is electrically isolated from the bellows.

Claims

Moreover, in the liquid metal fuse, in order to control the nominal response current, the ends of the capillary channels placed in the contact cap where the bellows is located can be provided with threaded plugs. In the drawing, the image is a liquid metal fuse, slit. In the electrically insulating housing 1, in the upper contact cap 2 and in the lower contact cap 3 there are capillary channels 4 filled with liquid metal. The diameter of the channels is chosen based on the condition of obtaining a capillary effect for the liquid metal, i.e. the metal cannot flow from the channels under the influence of its own gravity, and if they are not filled, it cannot flow into them. Inside the upper contact cap 2 there is installed a bellows 5, and on the front part of this cap an electromagnet of the armor type is placed, consisting of body 6, cover 7, winding 8 and core 9. Electromagnet body 6 is electrically isolated from the top contact cap 2 by means of an annular insulating inserts 10. The anchor 9 is connected to the bellows 5 by means of a puff 11. The anchor 9 and the poles 11 are electrically isolated from the bellows 5 by means of an insulating sleeve 12. The bellows 5 is installed in the contact cap 2 so that between the bellows 5 and the upper ends of the canal s 4 there is some buffer volume 13 is not filled with liquid metal. The pins 14 prevent the contact caps 2 and 3 from turning relative to the electrically insulating body 1 during the assembly of the liquid metal guard. The lower ends of the capillary channels 4 in the contact cap 3 are closed by plugs 15 (for example, screw). threaded plugs 16 can be installed in the upper ends of some capillary channels 4. The liquid metal fuse operates as follows. In normal operation, the current flows from the contact cap 2 through the liquid metal in channels 4 to the lower contact cap 3. When a short circuit or a current flows, the liquid metal in the channels 4 evaporates, and the resulting pressure displaces a significant proportion metal vapor in the buffer volume 13. After the vapor has cooled, it condenses. The liquid metal formed in this way does not drain from the buffer volume 13 into the channels 4, since this is prevented by the capillary properties of the channels. A minor part of the metal vapors remaining in channels 4 is insufficient for the formation in the channels 4 of electrically conductive bridges after condensation of the vapors. Consequently, the contact cap 2 is electrically disconnected from the contact cap 3. To restore the liquid metal fuse, a short current is applied to the winding 8 of the electromagnet. At the same time, the electromagnet's bark 9 is drawn into the inside of the housing 6 and through the brush 11 it acts on the bellows 5, which forces the liquid metal from the buffer volume 13 into the channels 4. Recovery of the liquid metal guard can be done by pressing the projecting end of the core 9 {if there is a fault power supply winding 8 electromagnet). In order to reduce the danger of injury to personnel by electric current, an annular insulating insert 10 and an insulating sleeve 12 are introduced into the design of the liquid metal fuse. If the requirement of manual repair is not presented to the fuse, then the insert 10 and the sleeve 12 can be removed, i.e. the fuse design is somewhat simplified. Making the fuse insert in the form of several (rather than one) capillaries allows to increase the rated current of the liquid metal fuse. To change the rated current, it is possible to change the number of channels 4. It is more convenient with a constant (maximum) number of channels 4 to change the nominal current in the direction of decreasing, disconnecting some of these channels using threaded plugs 16. Channels 4, closed with plugs on both sides, during assembly the fuse is not filled with liquid metal. As the liquid metal in the proposed fuse, sodium can be used, the gallium eutectic is more convenient. The advantage of gallium eutectics is the absence of toxicity. Since the transition temperature to liquid for gallium eutectics is about 5 ° C, then gallium tectics should be used in indoor electrical installations with a fusible insert from the galli tectics eelectric fuse. As can be seen from the above, spontaneously self-healing of the proposed liquid metal fuse does not occur. Consequently, the fuse does not require the installation of a circuit breaker with it. The absence of a circuit breaker simplifies the circuit of the circuit to be protected and significantly reduces it. Claims I. A liquid metal fuse comprising an electrically insulating housing with contact caps, a liquid metal fuse insert and a damper housed in one of the contact caps, characterized in that, in order to increase the reliability of disconnection of the protected circuit. It is equipped with an electromagnet and a choke installed in a contact cap where the damper is located, the liquid metal melting insert is made in the form of several parallel capillary channels, the bellows is used as the damper, and the electromagnet is connected through the brush to the damper.

2. Fuse according to claim 1, characterized in that the body of the electromagnet is electric