SU1267185A2 - Vacuum relay - Google Patents

Abstract

VACUUM RELAY on auth. No. 1065705, whether it is By the fact that, in order to increase the accuracy of work, it is supplied with a source of stabilized direct current, connected to a series circuit of a membrane, a contact pair, a contact group, a supply nipple and a load resistance. (L hch

Description

The invention relates to vacuum technology and can be used to improve the accuracy and reliability of the relay in operation when. higher temperatures.

The invention is an improvement on the device auth.St. № 1065705

In a known invention, a vacuum relay is described, comprising a housing within which a sealed cavity with a sensitive membrane is formed. The relay also contains an electrically insulated cover, a pair of connecting contacts, one of which is made on the membrane, a contact spring and a movable fitting. The movable sleeve and its adapter are connected by a threaded joint and are freely mounted in guides along the direction of movement of the membrane.

The second contact of the relay is placed in the center of the membrane inside the adapter, electrically insulated from it and connected through contact springs; well, to the inlet fitting, which is mounted on the key.

The disadvantage of such a relay is the impossibility of using it as an analyzer for precision measurements due to the presence on the contact pair of a surface film, for example, an oxide film, which increases the resistance of the transition contact, which is especially noticeable at low contact forces.

Since the resistance of the insulation elements of the relay at high temperatures drops, the initial contact between the contact and the membrane is difficult to register with sufficient accuracy.

Only at a certain value of the voltage breakdown occurs (Fritting) and the resistance of the transition contact drops sharply.

The magnitude of such a voltage for chromium-nickel steels is more than 15V. However, it is impossible to bring a contact of such a magnitude to the Hia contact, since at the time of contact closure, with a sharp increase in the current, the contact pair will burn. The use of load resistance makes it possible to limit the amount of current, but it does not allow to precisely fix the initial moment of the contact pair closure (contact-membrane), since in the moment

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The fritting increase in the current through the contact and, consequently, through the load resistance leads to an increase in the voltage drop across this resistance and, consequently, to a drop in the voltage across the transition contact when the value (s) is below the Fritting. This leads to the appearance of fluctuations on the load resistance, which, secondly, are not distinguishable from the fluctuations of the leakage currents on the insulation, which makes it impossible to carry out precision measurements.

The aim of the invention is to improve the accuracy of the vacuum relay.

The goal is achieved by the fact that the vacuum relay is auth.St. No. 1065705 is supplied with a source of stabilized direct current, connected to a series circuit consisting of a membrane, a contact pair, a contact wire, under the water connection and a load resistance.

The source of stabilized direct current is adjusted to a certain allowable value of the current through the contact, an increase in the contact resistance causes an increase in the voltage at the transition to Fritting (the current does not change). Provided that the Fritting voltage is automatically maintained, the voltage on the load resistance will not change from Fritting until the full opening (opening) of the start of the contacts. Moreover, the magnitude of the voltage on this cross section at the time of Fritting will be substantially greater than the voltage from the leakage currents on the insulation, since the contact resistance at the time of Fritting is units of Ω.

An example of a specific implementation of the analyzer is shown in the drawing.

The relay contains a housing 1, which serves as a sliding contact for a membrane 2, which rests with the center on a fixed contact 3, which is isolated electrically from the housing. The adapter 4 is screwed into the movable sleeve 5., located in the body guides 6 and secured with a nut 7. The sleeve 5 is pressed by the contact spring 8 to the body stops 9, i.e. in the initial state, it is only driven upward along the vertical axis. The spring 8 at the same time makes electrical contact with the inlet fitting 10, through which the fixed contact 3 positions can be adjusted. The reaction vessel 14 is attached to the housing 1 by means of a seal 15, washers 16 and a nut 17. A source of stabilized direct current 18 is connected to a series circuit of membrane 2, contact pair 2 and 3, contact spring B, inlet fitting 10 and load resistance 19.

The relay works as follows.

When the vacuum under the membrane changes, the latter bends. A measurement system (not shown) commands the gas to be pumped out through fitting 9 At the moment when the pressure under the membrane 2 and above it is equal, the contact pair 2 and 3 will close. A command is issued to measure the amount of vacuum. . The source of stabilized DC 18 is set to a valid value of the current through the contact pair 2 and 3.

Since the Fritting voltage will be maintained automatically by a source of stabilized direct current, the voltage across the load resistance 19 will not change from the moment of the start of the Fritting until full closed (open)

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contacts. This allows more t04 but to determine the moment of equality of pressures and increase the sensitivity and accuracy of the relay.

5 After the end of the vacuum change, the measurement system on command connects the nozzle 10 to the atmosphere, and the membrane 2 again bends. Further, the measurement processes are repeated. 10 If the process of changing the pressure in the reaction vessel occurs, then in the initial state, membrane 2 is bent upwards. Under the influence of the membrane 2, the spring 8 is compressed, and the contact 15 3 moves upwards. The membrane 2 is placed on the anvil 9 of the housing 1 and thereby protects it from the influence of the excessive pressure.

With experimental verification of the Ge20, the current necter was tuned. the amount of current through the contact 5 mA, a; the maximum voltage of the GBerator with an open output of 20 V. In this case, the leakage current did not exceed 1 mA. 25 The use of exemplary pressure measuring instruments made it possible to establish that the proposed device makes it possible to measure pressure with an accuracy of 0.1%.

The technical and economic effect lies in the fact that maintaining a constant voltage on the loading resistance from the moment of the start of Fritting to the complete closing (opening) of the contacts makes it possible to more accurately determine the moment of equality of the measured and compensatory pressures and improve the accuracy of the relay.

Claims (1)

VACUUM RELAY by ed. No. 1065705, characterized in that, in order to improve the accuracy of operation, it is equipped with a stabilized direct current source connected to a serial circuit from a membrane, a contact pair, a contact group, a supply fitting and load resistance. SU ,, 1267185