JP2873934B2 - Rotary viscometer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary viscometer using a superconducting magnetic bearing.

[0002]

2. Description of the Related Art A conventional rotary viscometer will be described.

FIG. 5 shows an example of a conventional rotary viscous vacuum gauge, in which a part of a measuring head is cut away and its control system is shown in a block diagram. In this figure, reference numeral 1 denotes a measuring head, and 2 denotes a rotating body of a magnetic stainless steel ball having a diameter of, for example, 4.5 mm, which is a transducer for converting an attenuation rate of natural rotation into a pressure of a measuring gas. Reference numeral 3 denotes a non-magnetic stainless steel pipe-shaped rotating body chamber which accommodates the rotating body 2 and has, for example, an outer diameter of 8.5 mm. Reference numerals 4a and 4b denote permanent magnets which are disposed vertically facing each other. It is for magnetic suspension. 5a and 5b are the rotating bodies 2
, A vertical misalignment correction coil, 6 is a controller, 7a
7d are coils for correcting the displacement of the rotating body 2 in the horizontal direction (7c and 7d are not visible in FIG. 5), 8a to 8d are driving coils for generating a rotating magnetic field, 9 is a temperature sensor, 10a,
10b is a detection coil for detecting the rotation of the magnetization vector of the rotating body 2, 11 is a three-phase AC power supply for generating a rotating magnetic field in the drive coils 8a to 8d, 12 to 15 are transformers, and 16 is an integrator 17 Is a computer that receives the output from each coil and performs calculation and control.

[0004] The operation thereof will be briefly described. The magnetically levitated rotating body 2 is applied to the driving coils 8a and 8b by a rotating magnetic field for about 4 hours.
00r. p. After acceleration to s, the driving is stopped, and the rate at which the number of revolutions attenuates due to the viscous resistance of the gas to be measured is detected. On the other hand, the function of the computer 17 detects the attenuation rate from the rotation cycle detected by the measuring head 1 and converts the viscosity coefficient of the gas, which is input in advance by the computer 17, into pressure and displays it.

[0005] In order to detect the temperature near the rotating body 2, a temperature sensor 9 is fixed to the rotating body chamber 3, from which a temperature signal υ is output.
Which is input to the transformer 12. Where the voltage V
_T is generated and input to the computer 17. In addition,
Instead of the temperature sensor 9, one of the coils 7a, 7b and 8a to 8d may be used. In other words, so that the voltage generated by the temperature dependence of the resistance value R is taken out as a signal V _T from the transformer 13.

On the other hand, cause the signal V _I in accordance with the on time of the three-phase AC power source 11 tau, the voltage V _P which is proportional thereto is generated from the transformer 14. The data is further input to a computer 17 through an integrator 16.

Further, it is also entered into the computer 17 through the integrator 16 because even obtain a voltage V _d corresponding to the on time τ from transformer 11. The temperature correction of the pressure display value of the computer 17 is performed by combining these two inputs.

FIG. 6 shows a main part of another example of a conventional rotary viscous vacuum gauge, and shows only a portion of a rotary shaft floating holding mechanism. In this figure, reference numeral 21 denotes a ring-shaped permanent magnet which is magnetized on the upper and lower surfaces. Reference numeral 22 denotes a disk made of a superconducting material, reference numeral 23 denotes a non-magnetic disk attached to the disk 22, reference numeral 24 denotes a non-magnetic shaft to which a non-magnetic blade 25 is attached. ing. 26 is the disk 22
Holes are provided at equal intervals around the light emitting device;
Is provided opposite to a position where light emitted from the light emitting device 27 is incident on the light receiving device 28 through the hole 26 in the light receiving device. 2
Reference numeral 9 denotes a pulse counter for counting the number of light incidents on the light receiving device 28. The upper end of the shaft 24 is a free end.

The operation is performed by the permanent magnets 2 arranged vertically.
Disk 1 made of superconducting material because 1 is fixed
2 floats due to the Meissner effect and is held in a non-contact manner. Then, the drive is stopped after accelerating the shaft 24 by appropriate means, the rate of decrease in the number of revolutions is detected from the number of pulses of the pulse counter 29, and the degree of vacuum is measured in the same manner as in the conventional example of FIG.

The conventional example shown in FIG. 6 uses a non-contact rotating shaft holding mechanism in which a shaft 24 of a blade 25 is vertically mounted on a permanent magnet 21 floating on a disk 22 of a superconducting material.

[0011]

The rotary shaft floating and holding mechanism in the conventional rotary viscometer of FIGS. 5 and 6 described above focuses only on the stable floating and holding of the masses of the rotating body 2 and the blades 25. There is no assurance that the rotation axis will be displaced from the vertical and no turbulent rotation accompanied by pulsation or precession will occur, and no specific precautionary measures have been taken.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a rotating shaft levitation holding mechanism capable of stably holding a rotating shaft by using a superconducting magnetic levitation holding mechanism, and to provide the same. An object of the present invention is to provide a rotary viscometer used.

[0013]

A rotary viscous vacuum gauge according to the present invention includes a rotary shaft floating holding mechanism for magnetically levitating and holding a rotationally symmetric sample with rotation. A superconducting magnetic levitation holding mechanism composed of non-contact superconducting bearings is used at the upper and lower ends of a rotating shaft to be kept vertical, and the non-contact superconducting bearing has a vertical portion and a horizontal portion without holes. And a recess having a recess for receiving each of both ends of the rotating shaft.

[0014]

Since the upper and lower ends of the present invention are held by superconducting magnetic bearings, there is no pulsation of the rotating shaft or precession.

[0015]

1 (a) and 1 (b) are a front view and a plan view of a sample showing a portion of a rotary shaft floating holding mechanism of a rotary viscous vacuum gauge showing an embodiment of the present invention. In this figure, 3
Reference numeral 1 denotes a vertical rotation shaft which supports the sample 32A in an axially symmetric manner, and whose upper and lower ends are N-pole and S-pole magnetized. The sample 32A has a windmill shape as shown in the plan view of FIG. 33 and 34 are upper and lower non-contact superconducting bearings,
The upper and lower portions of the vertical rotation shaft 31 are supported in a non-contact manner by the Meissner effect. That is, the upper and lower ends of the vertical rotation shaft 31 are N
Pole and S pole are magnetized. For this purpose, the vertical rotating shaft 31 itself is made of a magnetic material and magnetized, or permanent magnets are attached to the upper and lower ends of the vertical rotating shaft 31. When the non-contact superconducting bearing 33 enters the superconducting state, the upper and lower ends of the vertical rotating shaft 31 receive repulsive forces due to the Meissner effect, and are held in a non-contact manner. Reference numeral 35 denotes a spur gear fixed to the vertical rotation shaft 31. A drive gear 36 is attached to an output shaft of the electric motor 37. At the time of starting, the drive gear 36 is driven by the electric motor 37,
When the spur gear 35 meshing with the spur gear 35 is driven and given rotation is given to the vertical rotation shaft 31, the electric motor 37 is moved as indicated by a dotted arrow to separate the drive gear 36 from the spur gear 35. Thereafter, the degree of vacuum is measured in the same manner as in a conventional rotary viscometer. As described above, since the vertical rotation shaft 31 is supported at the upper and lower ends in a non-contact manner, precession movement and irregularity do not occur.

FIG. 2 is a front view showing another embodiment of the present invention. This embodiment is different from the embodiment of FIG. 1 in that the sample 32B forms a sphere. Others are the same as FIG. However, the motor 37 and the like for performing initial driving are omitted.

FIGS. 3 (a) and 3 (b) are a front view and a plan view of a drive coil showing still another embodiment of the present invention. In this embodiment, the sample 32C has an elliptical cross section.
FIG. 3B is a plan view of the starting coil, and is omitted in FIG. 3A. As described above, two pairs of starting coils 38a and 38b and 39a and 39b are provided.

FIGS. 4A and 4B are a front view and a plan view showing still another embodiment of the present invention. This embodiment is different from the embodiment of FIG. 1 in that the sample 32D has a water wheel shape. Others are the same as FIG. However, the motor 37 and the like for performing initial driving are omitted.

In the case of the embodiment shown in FIGS. 1, 2 and 4, the samples 32A, 32B and 32D are magnetized as shown in FIG. The initial drive can be performed using the coil without using the electric motor 37. Reference numeral 40 denotes a pickup coil for detecting the number of rotations in the vicinity of the magnetic pole.

[0020]

The rotary viscometer according to the present invention has a non-contact superconducting mechanism as a rotating shaft floating holding mechanism for magnetically levitating and holding a rotating body at both upper and lower ends of a rotating shaft to be kept vertical.
Comprising a superconducting magnetic levitation holding mechanism consisting of bearing, the non-contact
The superconducting bearing has a concave part with a vertical part and a horizontal part without holes.
Receiving each of the two ends of the rotating shaft in the recess.
With such a configuration, there is an advantage that the rotation axis does not pulsate and precession does not occur, and accurate measurement can be expected.

[Brief description of the drawings]

FIGS. 1A and 1B are a front view and a plan view showing an embodiment of a rotary shaft floating holding mechanism in a rotary viscous vacuum gauge according to the present invention.

FIG. 2 is a front view showing another embodiment of the present invention.

FIG. 3 is a front view and a plan view of a drive coil showing another embodiment of the present invention.

FIG. 4 is a front view and a plan view showing another embodiment of the present invention.

FIG. 5 is a block diagram illustrating a control system in which a part of a measurement head showing an example of a conventional rotary viscometer is cut away.

FIG. 6 is a diagram showing a main part of another example of the conventional rotary viscous vacuum system.

[Explanation of symbols]

 31 Vertical rotating shaft 32A Sample 32B Sample 32C Sample 32D Sample 33 Non-contact superconducting bearing 34 Non-contact superconducting bearing 35 Spur gear 36 Drive gear 37 Electric motor

Claims (1)

(57) [Claims] 1. A rotary viscous vacuum gauge provided with a rotating shaft floating holding mechanism for magnetically levitating and holding a rotationally symmetric sample accompanied by rotation, wherein the rotating shaft floating holding mechanism includes a rotating shaft that is to be kept vertically. Using a superconducting magnetic levitation holding mechanism consisting of a non-contact superconducting bearing at both ends, the non-contact superconducting bearing has a concave portion having a vertical portion and a horizontal portion without holes, and the concave portion has A rotary viscometer that accepts both ends.