JP2583924Y2 - Clean pump - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a clean pump, which is applied to a semiconductor manufacturing plant, medical equipment, and the like. The impeller itself is held at a predetermined position in a casing and rotated by a magnetic action from outside the casing. Related to clean pump.

[0002]

2. Description of the Related Art As a clean pump used in a semiconductor manufacturing plant or the like, there is one known in Japanese Patent Application Laid-Open No. Hei 3-22987.

FIG. 5 is a longitudinal sectional view of such a clean pump. In FIG. 5, an impeller 3 is provided in a casing 2 of the pump 1. The impeller 3 includes a non-magnetic member 5 having a permanent magnet 4 constituting an uncontrolled magnetic bearing, and soft iron corresponding to a rotor of the controlled magnetic bearing. The member 6 is connected. The permanent magnet 4 is divided in the circumferential direction of the impeller 3, and portions adjacent to each other are magnetized in opposite directions. As opposed to the permanent magnet 4 of the impeller 3,
A rotor 8 supported on a shaft 7 is provided outside the casing 2. The rotor 8 is driven and rotated by a motor (not shown). The same number of permanent magnets 9 as the number of impellers are attached to the rotor 8 so as to face the permanent magnets 4 of the impeller 3 and to apply an attractive force.

On the other hand, the casing 2 faces the side having the soft iron member 6 of the impeller 3 so that the impeller 3 can be held at the center of the casing 2 by overcoming the attractive force of the permanent magnets 4 and 9. A working electromagnet 10 is provided.

The gap between the electromagnet 10 and the soft iron member 6 is detected by a position sensor (not shown), and the electromagnet is controlled by a control unit (not shown) in accordance with the detection output, so that the impeller 3 is held at the center of the casing 2. . Even if a radial force acts on the impeller 3 due to gravity or the like, the shear force of the magnetic flux between the permanent magnets 4 and 9 and the shear force of the magnetic flux between the electromagnet 10 and the soft iron member 6 act. 3 is held at the center of the casing 2.

When the rotor 8 rotates with the impeller 3 magnetically supported in this manner, the permanent magnets 4 and 9 are rotated.
And constitute a magnetic coupling, impeller 3 rotates,
The liquid is sent to a discharge port (not shown).

[0007]

In the clean pump shown in FIG. 5, the impeller 3 receives a force in the direction of arrow F shown in FIG. 5, and the load of the control type magnetic bearing by the electromagnet 10 and the soft iron member 6. If the capacity is exceeded, the floating control of the impeller 3 becomes impossible, and the impeller 3 may come into contact with the inner wall of the casing 2. Further, even if the load capacity of the control type magnetic bearing is not exceeded, self-heating of the electromagnet 10 may increase, and the temperature of the liquid in the casing 2 may increase.

Therefore, a main object of the present invention is to provide a clean pump capable of preventing the controllable magnetic bearing from being unable to be controlled while the impeller is rotating, and preventing self-heating of the controllable magnetic bearing from increasing. It is to be.

[0009]

According to the present invention, a first permanent magnet provided on one surface of an impeller and a second permanent magnet provided on an outer surface of a rotor opposed to one surface of the impeller via a casing are provided. In a clean pump in which a permanent magnet and a non-controllable magnetic bearing are configured, and a controllable magnetic bearing is configured by a magnetic member provided on the other surface of the impeller and an electromagnet provided to face the other surface of the impeller, A plurality of dynamic pressure grooves for generating dynamic pressure are formed on one surface of the impeller, and the control of the controlled magnetic bearing is stopped when the impeller reaches a predetermined number of revolutions, and the non-controlled magnetic bearing is stopped. The impeller is configured to float and rotate by a dynamic pressure having a strength corresponding to the suction force of the impeller.

[0010]

In the clean pump according to the present invention, the dynamic pressure groove is formed on one surface of the impeller, so that the impeller can be lifted and rotated by the dynamic pressure having a strength balanced with the attraction force of the permanent magnet coupling. Therefore, it is possible to eliminate the possibility that the controllable magnetic bearing cannot be controlled during the rotation of the impeller or the self-heating of the controllable magnetic bearing increases.

[0011]

1 is a longitudinal sectional view of one embodiment of the present invention, FIG. 2 is a view showing one surface of the impeller shown in FIG. 1, and FIG. 3 is a sectional view taken along line III-III of FIG. FIG.
FIG. 4 is a sectional view taken along the line IV-IV in FIG.

The clean pump shown in FIG. 1 is configured in the same manner as in FIG. 5 except for the following points. That is, as shown in FIG. 2, the permanent magnets 4 for transmitting the rotational force from the rotor 8 to one end of the impeller 3 are equally divided on the same circumference at every angle and the adjacent permanent magnets have different polarities. And a dynamic pressure groove 11 as shown in FIG. 2 is formed on the same end face. This dynamic pressure groove 1
1 generates a constant dynamic pressure between the impeller 3 and the casing 2 as the impeller 3 rotates. In the example shown in FIG. 2, the dynamic pressure groove 11 is formed in a herringbone (shape), but the groove is not limited to this and may have any shape so as to generate dynamic pressure. There may be.

In the clean pump constructed as described above, the impeller 3 has a controlled magnetic bearing composed of the electromagnet 10 and the soft iron member 6 with an attractive force that is in proportion to the magnetic coupling attractive force of the permanent magnets 4 and 9. From the casing 2
Rotate by magnetic levitation without contact inside. The impeller 3 generates a dynamic pressure between the impeller 3 and the inner surface of the casing 2 as the impeller 3 rotates. After the generation of the dynamic pressure, the rotation speed of the impeller 3 is detected by a detector (not shown), and when the rotation speed reaches a preset rotation speed, the control of the electromagnet 10 is stopped. At this time, the impeller 3 has the permanent magnets 4 and 9
Generates a dynamic pressure of a strength that balances the suction force of
Levitate and rotate without touching inside.

[0014]

As described above, according to the present invention, a plurality of dynamic pressure grooves for generating dynamic pressure are formed on one surface of the impeller facing the casing, and the impeller has a predetermined rotation speed. In response to this, the control of the control type magnetic bearing was stopped, a dynamic pressure of a strength corresponding to the attraction force of the non-control type magnetic bearing was generated, and the impeller was lifted and rotated.
This makes it possible to prevent the controllable magnetic bearing from becoming uncontrollable while the impeller is rotating, and to prevent self-heating of the controllable magnetic bearing from increasing.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of one embodiment of the present invention.

FIG. 2 is a view showing one surface of the impeller shown in FIG. 1;

FIG. 3 is a sectional view taken along line III-III in FIG. 2;

FIG. 4 is a sectional view taken along the line IV-IV in FIG. 2;

FIG. 5 is a longitudinal sectional view of a conventional clean pump.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Pump 2 Casing 3 Impeller 4, 9 Permanent magnet 5 Non-magnetic member 6 Soft iron member 8 Rotor 10 Electromagnet 11 Dynamic pressure groove

Claims (1)

(57) [Scope of request for utility model registration] 1. An uncontrolled system comprising: a first permanent magnet provided on one surface of an impeller; and a second permanent magnet provided on an outer surface of a rotor to face one surface of the impeller via a casing. A clean magnetic pump comprising a magnetic member provided on the other surface of the impeller and an electromagnet provided to face the other surface of the impeller. Forming a plurality of dynamic pressure grooves for generating dynamic pressure on one surface, stopping the control type magnetic bearing in response to the impeller reaching a predetermined number of revolutions, the non-control type magnetic bearing Wherein the impeller is levitated and rotated by a dynamic pressure having a strength corresponding to the suction force of the clean pump.