JPH08180776A - Vacuum pressure measuring apparatus - Google Patents

Abstract

PURPOSE: To provide a vacuum pressure measuring apparatus in which the intensity of a magnetic field can be adjusted easily and of which a connection part to fix a plurality of coil parts is hardly broken by thermal expansion and contaction. CONSTITUTION: A vacuum pressure measuring apparatus is composed of at least a d.c. voltage circuit 2 to make electric current run in and apply d.c. voltage to a pair of electrodes 6A, 6B installed in a vacuum container 5 and an exitation d.c. circuit 3 to make d.c. current run in a solenoid coil 8 installed in the outer circumference of the vacuum container to generate a magnetic field H in order to amplify the ion current (i). A first conductor piece 10A in the inner-most layer and a second conductor piece 10B in the outer most layer of a coil part 20 composed of a plurality of layers connected in series are so set as to face to the inside and the outside, respectively, and a connection part 10 which fixes respective coil parts 20 between the conductor pieces by a fixing means is so installed in the middle layer of the inner- and outer most layers as to make both conductor pieces 10A, 10B overlapped each other and thus a solenoid coil is composed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vacuum pressure measuring device having an improved solenoid coil.

[0002]

2. Description of the Related Art Conventionally, a magnetron test method has been widely used as a method for measuring the vacuum pressure of a vacuum valve for a vacuum circuit breaker. In the magnetron test method, a magnetic field is generated in a vacuum container to be measured and a high voltage is applied between a pair of electrodes in the vacuum container to be measured, thereby generating a spiral electron flow. This electron flow increases the number of times of ionization of gas molecules in the vacuum container to be measured to obtain a larger ion current.

Since this ion current is proportional to the density of gas molecules in the vacuum container to be measured, it cannot be detected in the high vacuum region. In order to extend the measurement range to the high vacuum region, it is necessary to obtain a larger ion current.

By the way, when the vacuum pressure of the vacuum valve is measured before shipment from the factory, the vacuum valve alone can be used. Therefore, the shape of the vacuum measuring device is not selected, but the vacuum is measured while it is mounted on the vacuum circuit breaker. For vacuum pressure measurement of valves,
There is a method of attaching a measuring device such as a magnetron element to the vacuum valve, but this has not been realized because it causes a cost increase. Further, as a simple measurement method, there is a method of knowing the vacuum pressure in the vacuum container to be measured by detecting a high frequency generated when a glow discharge occurs between the electrodes.

However, this system has an internal vacuum pressure of 4 × 1.
It is effective for the vacuum degree inspection of the glow discharge region of 0 ^-1 [Pa] (3 × 10 ^-3 [Torr]) or more, but it is the guaranteed limit value of the vacuum valve, 7 × 10 ^-2 [Pa] (5 Values below × 10 ^-4 [Torr]) cannot be measured.

Further, in the vacuum pressure measuring device disclosed in Japanese Patent Laid-Open No. 62-237625, a vacuum valve is inserted into an opening between legs extending from both ends of the central iron core, and the central iron core corresponding to the vacuum valve is inserted. A magnetic path is formed in which a magnetic flux generated when a solenoid coil is mounted and an electric current is applied to the solenoid coil passes through the central iron core, the leg iron core, and the vacuum valve.

[0007]

However, in this magnetic path, the number of turns of the solenoid coil cannot be changed to adjust the strength of the magnetic flux.

An object of the present invention is to provide a vacuum pressure measuring device which facilitates adjusting the strength of magnetic flux.

Still another object of the present invention is to provide a vacuum pressure measuring device in which breakage of the connecting portion of the solenoid coil is reduced.

[0010]

In order to achieve the above object, the vacuum pressure measuring device of the present invention applies at least a pair of electrodes arranged in a vacuum container and a DC voltage for flowing an ionic current between the electrodes. A device for measuring a vacuum pressure with a vacuum pressure measuring device comprising a direct current voltage circuit and a direct current circuit for applying a direct current to a solenoid coil for generating a magnetic field for amplifying the ion current arranged on the outer circumference of a vacuum container,
Arranged so that the conductor pieces of the innermost layer and the outermost layer of the multiple-layered coil portions connected in series face inward and outward, respectively.
The solenoid coil is configured by connecting portions in which the conductor pieces of the coil portions are arranged so as to overlap each other in the intermediate layer of both layers, and the conductor pieces of the coil portions are fixed by the fixing means.

[0011]

Since the fixing means is removed so that the coil portions can be disassembled, the strength of the magnetic flux can be easily adjusted. Further, when each connecting portion expands and contracts due to heat fluctuation, the connecting portion expands and contracts accordingly, and the damage of the connecting portion is reduced.

[0012]

Embodiments of the present invention will be described below with reference to FIGS. FIG. 5 is an equivalent circuit of a vacuum pressure measuring device using the solenoid coil of the present invention, and details of the solenoid coil will be described with reference to FIGS. 2 to 4.

In FIG. 5, the vacuum vessel 5 has a pair of fixed side electrodes 6A and movable side electrodes 6B which are freely contactable and separable inside, and a rod 16 extends from the back surface of both electrodes 6A and 6B to the outside. Normally, a current is flowing between the electrodes 6A and 6B, and when the fixed electrode 6A is separated from the movable electrode 6B, an arc is generated between the electrodes 6A and 6B, and the evaporated metal at that time is transferred to the vacuum container 5. It adheres to the attached shield 17 and cuts off the current. Since the interruption of the electric current is largely related to the vacuum pressure in the vacuum container, the vacuum pressure measuring device 1 is mounted outside the vacuum container 5 to measure the vacuum pressure.

A DC high voltage circuit composed of a DC high voltage power supply 2, a switch 7A and a measuring instrument 4 is formed at both ends of the rod 16. The DC high-voltage power supply 2 uses a DC power supply capable of boosting the voltage to 30 KV. When the switch 7A is closed to energize with the pair of fixed-side electrode 6A and movable-side electrode 6B hermetically sealed in the vacuum container, a minute current is discharged between the electrodes 6A and 6B.

The solenoid coil 8 of the present invention mounted on the outside of the vacuum container 5 has the exciting DC power source 3 and the switch 7B connected in series at both ends. A magnetic field is created by closing the switch 7B and energizing it to generate magnetron discharge in the vacuum container 5. A small current becomes an ionic current due to the magnetron discharge and is measured by the measuring device 4. Since the magnitude of the ion current is proportional to the vacuum pressure in the vacuum container, the vacuum pressure value can be obtained by converting the ion current value into the vacuum pressure value.

Vacuum pressure measuring device 1 having the above-mentioned structure
May be measured with the vacuum valve alone or with the vacuum valve mounted on the vacuum circuit breaker. INDUSTRIAL APPLICABILITY The present invention makes it possible to perform measurement while mounted on a vacuum circuit breaker in order to utilize it for predicting the service life of a vacuum valve (for maintenance, etc.) by the user.

When measuring the vacuum pressure with the vacuum valve mounted on the vacuum circuit breaker, a circular solenoid coil is mounted because the vacuum valve is fixed to the vacuum circuit breaker by an insulator or a molded insulating cover. Is not easy. Therefore, it is necessary to insert it into the space between the insulator or the insulating cover and the vacuum valve, and a solenoid coil that can be freely opened is required. This will be described in detail with reference to FIGS. 1 to 4.

FIG. 1 shows an openable solenoid coil 8
2A and 2B has a conductor 8A coated with an insulator 8B, and both ends of the conductor 8A are alternately stepped to expose the first conductor piece 9A and the second conductor piece 9B. create.
The first conductor piece 9A is exposed on the side opposite to the second conductor piece 9B, that is, on the lower side. The four coil portions 20 formed by bundling several conductors 8A into a coil shape are wound around and connected to each other in series at the connection portion 10.

The four coil parts 20 are composed of first to fourth coil parts 20A, 20B, 20 from the innermost layer to the outermost layer.
Called C, 20D. These coil parts 20A to 20D
Bends the conductor 8A into a coil shape with the first conductor piece 9A facing inward, and the second conductor piece 9B facing outward on the side opposite to the first conductor piece 9A.

The first coil portion 20 between the innermost layer and the outermost layer
The electrical connection between A and the fourth coil portion 20D is performed, for example, by arranging so that the second conductor piece 9B of the first coil portion 20A and the first conductor piece 9A of the second coil portion 20B overlap each other. Connected to each other. The second coil portion 20B to the fourth coil portion 20D are also performed in the same manner as described above, and the first coil portion 20A to the fourth coil portion 20D are electrically connected in series.

The second conductor piece 9B of the innermost and outermost first coil portions 20A and the first conductor piece 9 of the fourth coil portion 20D.
A is arranged so as to face the inside and the outside, respectively. Lead-out terminals 10A and 10B are provided on the second conductor piece 9B of the first coil portion 20A and the first conductor piece 9A of the fourth coil portion 20D.
Are arranged so as to be in contact with each other, and lead-out terminals 10A and 10B are further arranged.
The pressing metal fitting 10C is inserted through the insulating member 10D to fix the first conductor piece 9A and the second conductor piece 9B, the lead terminals 10A and 10B, and the insulating member 10D between the pressing metal fitting 10C.
In the insulating member 10D, the surface of the pressing metal fitting 10C corresponding to the lead terminals 10A and 10B is coated with a vinyl-based smooth and flexible insulator. An insulating spacer may be used instead of the insulating coating of this embodiment. The pressing metal fitting 10C is composed of an elastic member capable of absorbing a lateral stretching force. When using a bolt and a nut for the pressing fitting 10C, it is preferable to interpose an elastic member such as rubber or spring.

An exciting DC power source 3 and a switch 7B are connected in series to the lead terminals 10A and 10B. Switch 7
By closing B and energizing it, a vertical magnetic field H is created in the vacuum vessel 5 to generate magnetron discharge. Both electrodes 6 arranged with a gap by this magnetron discharge
The ion current i flowing between A and 6B is measured by the measuring device 4. Since the magnitude of the ion current i is proportional to the vacuum pressure in the vacuum container, the vacuum pressure value can be obtained by converting the ion current value into the vacuum pressure value.

In the vacuum pressure measuring device 1 of the present invention, the plurality of coil portions 20A to 20D connected in series are provided with the pressing member 10.
By attaching / detaching C, the number of turns of the coil portion can be freely increased / decreased according to the strength of the magnetic field H, so that the strength of the magnetic field H can be easily adjusted. Further, since the solenoid coil 8 may be formed by forming the single conductor 8A into a coil shape, a large-scale wire winding machine is not required, which facilitates manufacture.

On the other hand, when a current flows through the connecting portion 10 where many contact surfaces of the first conductor piece 9A, the second conductor piece 9B, etc. are gathered, the contact resistance becomes high, and the generated heat causes the coil portions 20A to 20A.
20D expands and contracts, but in the present invention, the second conductor piece 9B of the first coil portion 20A and the first conductor piece 9A of the fourth coil portion 20D.
The circumferential end surface 10E absorbs the expansion and contraction in the circumferential direction by making the circumferential direction a free end. Further, the expansion and contraction in the direction perpendicular to the circumferential direction, that is, in the left and right directions, is absorbed by the elastic force of the pressing member 10C. Therefore, the thermal expansion and contraction of the connecting portion 10 can be absorbed, and the damage of the connecting portion 10 can be significantly reduced.

[0025]

As described above, in the vacuum pressure measuring apparatus of the present invention, the solenoid coil is connected in series with a plurality of coil portions so that the number of turns of the coil portion can be freely increased or decreased, so that the strength of the magnetic field can be easily adjusted. I can do it now.

Further, the connecting portion for fixing the plurality of coil portions is less likely to be damaged by thermal expansion and contraction.

[Brief description of drawings]

FIG. 1 is a front sectional view of a solenoid coil shown as an embodiment of the present invention.

2A and 2B are a sectional view and a plan view of a conductor used in the solenoid coil of FIG.

FIG. 3 is an exploded perspective view of the solenoid coil used in FIGS. 1 and 2.

FIG. 4 is an enlarged cross-sectional view of a connection portion of the solenoid coil shown in FIG.

FIG. 5 is an equivalent circuit diagram of a vacuum pressure measuring device used for the vacuum valve shown as the embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Vacuum pressure measuring device, 2 ... DC voltage power supply, 3 ... Excitation DC power supply, 4 ... Measuring device, 5 ... Vacuum container, 6A ... Fixed side electrode, 6B ... Movable side electrode, 7A, 7B ... Switch, 8 ... Solenoid coil, 8A ... conductor, 9A ... first conductor piece, 9B
... 2nd conductor piece, 10A, 10B ... Lead-out terminal, 10C ... Push metal fitting, 20 ... Coil part.

Claims (2)

[Claims] 1. At least a pair of electrodes arranged in a vacuum container, a DC voltage circuit for applying a DC voltage for flowing an ion current between the electrodes, and a magnetic field for amplifying the ion current arranged on the outer periphery of the vacuum container. A device for measuring vacuum pressure with a vacuum pressure measuring device comprising a direct current circuit for flowing direct current to a solenoid coil coated with an insulating coating, which is formed by cutting the opposite ends of conductors used for the solenoid coil. The first conductor piece and the second conductor piece, the coil portion formed by deforming the conductor into a coil shape, and the connecting portion including the fixing means for fixing the conductor piece obtained by superposing the first conductor piece and the second conductor piece A vacuum pressure measuring device comprising the solenoid coil. 2. The conductor pieces of the innermost layer and the outermost layer of the plurality of coil portions connected in series are arranged so as to face inward and outward, respectively, and both conductor pieces are superposed on each other in an intermediate layer of both layers. 2. The vacuum pressure measuring device according to claim 1, wherein the solenoid coil is constituted by connecting portions arranged and fixing the conductor pieces of the respective coil portions by a fixing means.