JPH01110232A - Viscosity vacuum gauge - Google Patents

Abstract

PURPOSE:To enable the measuring of friction purely attributed to a gas viscosity while eliminating a mechanical friction, by mounting a blade and a disc made of non-magnetic material on a disc comprising a superconductive material to measure a rotational speed thereof non-contact when they rotate in a gas. CONSTITUTION:A disc 2 made of superconductive material is magnetically levitated by a magnetic field generated by a permanent magnet 1 together with a disc 3, a shaft 4 and a blade 5 all made of non-magnetic material. A rotary motion is applied to objects levitated centering around the shaft 4. The degree of attenuation of a rotational speed at this point is measured by receiving light from a light emitter 7 with a light receiver 8 through a hole 6 provided in the perimeter of the disc 3 made of non-magnetic material to count an output thereof with a counter 9. The degree of attenuation of the rotational speed represents a friction resistance with a gas, namely, viscosity of the gas.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] This invention relates to a vacuum gauge for measuring the pressure of low pressure, dilute gas.

[Conventional technology]

Various types of vacuum gauges have been put into practical use to measure the pressure of low-pressure, dilute gases. There is a viscous vacuum gauge that takes advantage of the property that the viscous force of gas acting on an object is proportional to pressure.

Examples include Langmuir Dunciman's molecular vacuum gauge, which rotates one of two parallel disks and measures the torsion of the other, and a tube that vibrates a thin crystal system and measures viscous force from the rate of decay. and so on.

[Problem that the invention seeks to solve]

However, with conventional viscous vacuum gauges like this.

It has been extremely difficult to put it into practical use due to the effects of mechanical friction and external vibration, and the difficulty in measuring damping.

This invention was made to solve the above-mentioned problems by eliminating mechanical friction.

The purpose of this invention is to obtain a device that can measure purely gas viscosity friction in a simple manner.

[Means for solving problems]

The viscous vacuum gauge according to the present invention magnetically levitates a disc made of superconducting material, adds a non-magnetic disc and blades to this disc, rotates these, and then circles the disc in a non-contact manner. It is designed to measure the rotational speed of the plate.

[Effect]

In this invention, since the rotational speed of the magnetically levitated superconducting disk and non-magnetic disk and blade is attenuated only by frictional resistance with the gas, the degree of attenuation of this rotational speed is measured without contact. By this, the viscosity of the gas is determined.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings.

In the figure, (1) is a permanent magnet, (2) is a disk made of superconducting material, and (3) is a non-magnetic material (such as plastic) attached to disk (2) of superconducting material. A disc, (4) is a non-magnetic shaft, and (5) is a non-magnetic blade.

(6) is a hole made around the non-magnetic disc (3).

(7) is a light emitting device, (8) is a light receiving device, and (9) is a pulse counter.

The disk (2) made of superconducting material and the disk (3) made of non-magnetic material are joined with their centers aligned, and the axis (4) is erected perpendicularly to the center of these disks. It is being

The disk (2) made of superconducting material is made of non-magnetic material (
The circular disk (3), shaft (4), and nine blades (5) are magnetically levitated by the magnetic field of the permanent magnet (1), and there is no mechanical contact with other objects. state.

From this state, if only rotational motion is given to these floating objects, like spinning a top around the axis (4), they will continue to rotate forever in a vacuum.

When it is rotated in gas, the rotation rate is gradually attenuated due to the frictional resistance between it and the gas.

The degree of attenuation of this rotational speed is determined by the non-magnetic disc (3).
When the light receiving device (8) receives the light from the light emitting device (7) through the hole (6) made around the disk, a pulse-like signal is obtained in proportion to the rotational speed of the disk, and this is sent to the pulse counter (
By counting at 9), measurement can be performed in a non-contact state, so there is no difference in the fact that the decrease in rotational speed is due only to the frictional resistance with the gas.

In the above embodiment, nine blades (5) are provided in order to increase the frictional resistance with the gas and shorten the measurement time, but the shape and number of blades may be determined as necessary.

Also, even those without the shaft (4) and blades (5) at all.

Since frictional resistance exists between the disk and the gas, the principle of measurement remains the same.

In order to measure the rotational speed of the first disc without contact, in the above embodiment a hole (6) is provided around the second disc, but even if two reflective markers are attached to the surface of the disc, it is possible to measure the rotational speed of the second disc without contact. Measurements can be made.

In this embodiment, the magnetic field for magnetic levitation is obtained from two permanent magnets, but a coil may also be used.

〔Effect of the invention〕

As described above, according to this invention, a magnetically levitated object is rotated and the attenuation of its rotational speed is measured without contact. It is convenient, does not require periodic calibration because there are no parts that change over time, and has a simple structure, making it possible to obtain an extremely inexpensive device.

This is a perspective structural diagram. (1) is a permanent magnet, (2) is a disk made of superconducting material, (3) is a non-magnetic disk, (4)
is a non-magnetic shaft, (5) is a non-magnetic blade, (6) is a hole, (7) is a light emitting device, (8) is a light receiving device, and (9) is a pulse counter.

Claims (1)

[Claims] A viscous vacuum equipped with a disk made of a superconducting material, a blade made of a non-magnetic material, and a disk attached to the disk, and a mechanism for non-contact measurement of the rotational speed of the disk when it is rotated in a gas. Total.