JPH11303788A - Liquid feeding line pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent contamination of chemicals to be transferred by a liquid feeding line pump, and improve its maintenance property. SOLUTION: In an in-line screw pump for transferring liquid, a rotor 30 is radially supported by means of magnetic bearings 15 arranged on both ends of the rotor 30. The rotor 30 is axially supported by controlling type magnetic bearings 16 each having a conical control surfaced faced to a conical axial disc 35 attached to the end face of the rotor 30. The rotor 30 is magnetically floated and supported in a non-contact form by the bearings 15, 16. The rotor 30 is rotated without contact with the static side. Liquid is transferred by pumping function of a screw groove 33 formed on an outer periphery of the rotor 30.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid feed line pump suitable for transferring a special chemical such as a resist liquid or a liquid for a wafer protective film used in manufacturing a semiconductor device.

[0002]

2. Description of the Related Art Conventionally, as a liquid feeding device used for transferring the above-mentioned special chemical liquid, a positive displacement pump such as a piston type is installed in the middle of a liquid transfer line connecting a liquid supply source and a liquid supply destination. It is generally known that a liquid is sequentially sent out while compressing a liquid to a predetermined pressure by this pump.

On the other hand, it is widely used to install a pump and a motor in the middle of the liquid transfer line, and to install an in-line pump which can be easily attached in the middle of the piping. For this type of in-line pump,
A main shaft that rotates integrally with the impeller according to the rotation of the motor is provided, and the main shaft is rotatably supported by rolling bearings and sliding bearings.

[0004]

However, in the former using the above-mentioned conventional positive displacement pump, a piston type pump is disposed in the middle of the line piping.
There is a problem that the transfer of the liquid is not continuously smooth. On the other hand, in the latter case where an in-line pump is used, contact of a sliding member in a rolling bearing or a sliding bearing is inevitable, and this contact involves fine dust generation (particle generation). When such particles are mixed into the pumped liquid and mixed into a liquid transfer destination such as a semiconductor device manufacturing facility, the particles adhere to a semiconductor wafer or the like manufactured using the chemical solution to be transferred, and the quality thereof is reduced. There is a problem that leads to a decrease in

[0005] In a pump, a narrow gap (assembly gap) which is necessarily formed when assembling and assembling the components generally exists in the flow path of the pumped liquid. This allows
A stagnation region and a dead water region are formed in the flow path of the pumped liquid, and the liquid enters into the gaps, which rots over time to become a contaminated liquid. When the liquid gradually seeps into the pumped liquid, mixes into the pumped liquid of the pump, and mixes into a liquid transfer destination such as a semiconductor device manufacturing facility, the semiconductor manufactured using the chemical to be transferred is manufactured. There is a problem in that the contaminated liquid adheres to the wafer or the like and deteriorates its quality.

[0006] Further, the liquid accumulated in the stagnation area and dead water area in the flow path may be solidified and fixed with the passage of time. In such a case, the flow path may be narrowed and closed, which significantly deteriorates the pumping performance of the pump.
For this reason, the operation of the manufacturing apparatus or the like to which the pump transfers the liquid is hindered. For this reason, maintenance is required, and such a pump becomes a hindrance factor in production efficiency.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a liquid feed line pump which can prevent contamination of a chemical solution to be transferred and has improved maintenance.

[0008]

According to a first aspect of the present invention, there is provided an in-line screw pump for transferring a liquid, wherein the rotor is radially supported by magnetic bearings provided at both ends of the rotor. The rotor is axially supported by a control type magnetic bearing having a conical control surface provided opposite to a conical axial disk attached to both end faces of the rotor, and the rotor is magnetically levitated by both bearings. A liquid feed line pump characterized in that it is supported in a non-contact manner, rotates without contacting the stationary side at all, and transfers liquid by a pump action of a screw groove provided on an outer periphery of the rotor.

According to the present invention, the rotor is supported by the magnetic bearing in a non-contact manner in the radial and axial directions.
The rotor can be rotated without any contact with the stationary side, and the liquid can be transferred by the pumping action of the thread provided on the outer periphery of the rotor. Thereby, unlike a conventional pump using a rolling bearing or a sliding bearing, it is possible to prevent a problem of generation of particles (generation of particles) from a sliding portion. Therefore, it is possible to prevent the particles from being mixed into the liquid being pumped and from being mixed into the semiconductor device manufacturing equipment or the like to which the liquid is transferred.

Then, from the suction port and the discharge port of the pump,
Along the conical axial disks attached to both end surfaces of the rotor, a flow path is formed that extends substantially linearly in the axial direction, in which the pumped liquid is connected to the thread groove on the outer periphery of the rotor, so that the flow path of the pumped liquid is smooth. And is simplified. Thereby, the stagnation area and dead water area of the pumped liquid are eliminated, and the maintainability is improved.

According to a second aspect of the present invention, the liquid contact portions on the rotor side and the stationary side of the pump are formed by forming a water-repellent material or a film of the material, and the pumping liquid stagnation region is formed. Alternatively, the liquid supply line pump according to claim 1, wherein a dead water region is excluded.

[0012] Thus, the narrow assembly gap created by the combination between the parts constituting the pump is covered with the coating of the water-repellent material. Therefore, the liquid can be prevented from permeating into the narrow assembly gap, and the stagnation region and dead water region of the pumped liquid can be eliminated. Therefore, the liquid accumulated in the stagnation area and the dead water area rots over time and becomes a contaminant, and this liquid gradually seeps into the pumped liquid and mixes into the pumped liquid. And the like can be prevented from being mixed into the transfer destination device. Further, since the stagnation area and the dead water area in the flow path are eliminated, the liquid does not accumulate here, and there is no problem that the liquid is solidified and fixed over time. Thereby, maintainability is improved.

According to a third aspect of the present invention, the suction port of the pump, the liquid transfer portion by the screw groove, and the discharge port of the pump are each arranged substantially linearly in the axial direction. The liquid transfer part by the screw groove is provided along the gap between the conical axial disk surface attached to both end surfaces of the rotor and the control surface of the magnetic bearing provided opposite to the surface. 2. The suction port and the discharge port are connected in a substantially linear manner in the axial direction.
Or a liquid sending line pump according to 2. This allows
Since the flow path of the pumped liquid can be formed to extend substantially linearly in the axial direction, the efficiency of the pump can be improved.

According to a fourth aspect of the present invention, the rotor includes:
It is composed of a cylindrical portion and conical axial disks provided on both end surfaces of the cylindrical portion, and a motor rotor is built in substantially the center of the cylindrical portion, and both ends of a thread groove portion on the outer periphery of the cylindrical portion. 4. A permanent magnet, which constitutes a passive magnetic bearing, is provided in the portion.
A liquid sending line pump according to any one of the above. This makes it possible to provide a screw-type pump in which the rotor is non-contact floating supported by both the axial and radial magnetic bearings, with a compact structure. In general, there is provided a liquid sending line pump which is free from a problem of contamination and has excellent maintainability.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. In the drawings, the same reference numerals indicate the same or corresponding parts.

FIGS. 1 and 2 show a liquid feed line pump according to a first embodiment of the present invention. This pump is used, for example, when manufacturing a semiconductor device or the like, and is suitable for a transfer line for transferring a special chemical such as a resist liquid or a liquid for a wafer protective film. That is, for example, it is used to send a chemically unstable special chemical solution from a transfer source tank or the like to a semiconductor manufacturing apparatus or the like at a transfer destination. At the suction port 11 of this pump, a suction pipe (not shown) as a part of the pipe of the liquid transfer line is mounted on the suction inner wall 11a, and similarly, a discharge pipe (not shown) is mounted on the inner wall 12a of the discharge port 12. . Therefore, a suction pipe (not shown), this pump, and a discharge pipe (not shown) are arranged substantially linearly, and inside the pump, liquid is supplied in the axial direction by rotation of a screw groove of a rotor, so-called in-line type. It is a screw pump.

This screw pump mainly comprises a stator 20 and a rotor 30 having a thread groove on the outer periphery. On the inner peripheral surface of the casing 21 at the center of the stator,
The motor stator chamber 22 is provided with a can 23. A motor stator 22b having a winding 22a is arranged in the motor stator chamber 22. In the motor stator 22b, a rotating magnetic field is formed by a current supplied to the winding 22a, and the motor rotor 32 disposed at a position facing the magnetic pole surface of the motor stator is driven to rotate, whereby the rotor 30 rotates.

A thread groove 33 is provided on the outer periphery of the central portion of the rotor 30.
When the rotor 30 is rotationally driven, the screw groove 33 also rotates, and the liquid existing in the space between the can 23 and the screw groove 33 is transferred. As a result, the liquid on the suction port 11 side is pumped to the discharge port 12 side.

The stator 20 includes an uncontrolled radial magnetic bearing 15 for supporting both ends of a rotor 30 on a casing 24.
, Whereby the rotor 30 is levitated and supported in the radial direction. In the radial magnetic bearing 15, the magnetic pole surfaces of the permanent magnet 15a on the stator side and the permanent magnet 15b on the rotor side are arranged to face each other, and the rotor 30 is brought into non-contact by the magnetic force acting between the magnetic pole surfaces. Floating supported.

An axial disk 35 made of a conical magnetic material is fixed to both end surfaces 30a of the rotor 30. A control electromagnet 25 is arranged to apply a magnetic force to the axial disk 35, and similarly, the conical control surface 25a faces the conical surface 35a of the axial disk 35 on the rotor side. The axial magnetic bearing 16 composed of the stator-side electromagnet 25 and the rotor-side axial disk 35 is a control-type magnetic bearing, and the axial floating position of the rotor 30 is set so that the rotor 30 is positioned at the target floating position. Is controlled.

That is, the axial sensor 2 is provided on the stator side.
6 for detecting the axial displacement of the rotor 30. Then, a control current is formed by a compensation circuit (not shown), and the control current is supplied to the coil 25b of the electromagnet 25 to adjust the magnetic force. As shown, in this pump, the axial magnetic bearings 16 are arranged on both the suction port 11 side and the discharge port 12 side. Thereby, the floating position of the rotor 30 in the axial direction is maintained at a constant target position regardless of the magnitude of the thrust force generated in the pump.

The gap 16 between the pole face 25a of the electromagnet 25 and the pole face 35a of the axial disk facing the pole face 25a is
It is the flow path of the pumped liquid. That is, the liquid in the suction port 11 passes through the flow path 16 and the permanent magnet 1 constituting the radial magnetic bearing.
The flow reaches the thread groove 33 of the rotor 30 through a flow path 15d provided in the gap 15 between 5a and 15b. Here, the liquid is pumped by the pumping action of the rotating screw groove 33.
And the permanent magnets 15a, which constitute the radial magnetic bearing,
Through a channel 15d provided in the gap 15 between the holes 15b,
Further, it reaches the discharge port 12 through the flow path 16 which is a gap between the magnetic pole surface 25a of the electromagnet 25 and the magnetic pole surface 35a of the axial disk opposed thereto.

Accordingly, the rotor 30 of this pump is composed of a cylindrical portion and a conical axial disk 35 provided on both end surfaces 30a of the cylindrical portion. A motor rotor 32 is built in substantially the center of the cylindrical portion, and a thread groove portion 3 corresponding to a pump blade is provided on the outer periphery of the rotor cylindrical portion.
3 are arranged. At both ends of the rotor cylindrical portion, permanent magnets 15b constituting a passive magnetic bearing are arranged. Thus, the rotor is supported in a non-contact floating manner by both the axial and radial magnetic bearings, and the rotor having a thread groove on its outer periphery can have an extremely compact structure.

The suction port 11 of the pump, the liquid transfer section 33 by a screw groove, and the discharge port 12 of the pump are each arranged substantially linearly in the axial direction. Then, the liquid transfer part 33 by the screw groove is provided at both end faces 30 of the rotor 30.
a along a flow path 16 in a gap between a surface 35a of a conical axial disk 35 attached to the magnetic disk control surface 25a and a control surface 25a of a magnetic bearing provided to face the surface 35a. The connection to the discharge port 11 and the discharge port 12 is as described above. The flow path 16 is formed substantially linearly in the axial direction along a conical surface as shown in the figure. Thereby, the flow path of the pumped liquid in the pump can be formed so as to extend substantially linearly in the axial direction as a whole, so that the stagnation area and dead water area of the pumped liquid are reduced, and the efficiency of the pump can be improved.

In this pump, the liquid contact portions on the rotor side and the stationary side are formed by forming a water-repellent material or a film of the material. That is,
As a material of the liquid contact part, a fluororesin or the like is used,
Alternatively, a treatment such as applying a fluororesin coating, a fluororesin lining, or a fluororesin-based paint is applied. For example, a bulk member such as a rotor body is formed of fluororesin, and can 23 or permanent magnets 15a, 15a.
A liquid surface of a metal material such as 5b or a magnetic material is coated with a fluororesin. The control electromagnet 2
The storage section in which the fifth coil 25a is disposed is sealed with an O-ring 27, and a liquid contact surface thereof is filled with a filling of a fluororesin. Further, the entire surface of the magnetic pole is coated with a fluororesin. The same applies to the sealing port of the axial sensor 26.

By using a water-repellent material on the liquid contact surface or by forming a film of the water-repellent material, the pumping of a special chemical such as a resist liquid or a liquid for a wafer protective film causes the metal constituting the pump to be pumped. No direct contact with material or magnetic material.
As a result, the metallic and magnetic materials that make up the pump
It is possible to prevent contaminants from being eluted in the pumped liquid by reacting with the special chemical. Further, in this pump, there is a narrow gap which is inevitably formed by assembling and assembling the parts, but the gap is covered by forming a film of a water-repellent material. Therefore, it is possible to prevent the liquid from permeating into the narrow gap in the assembly, and it is possible to eliminate the stagnant area and the dead water area of the pumped liquid.

The outline of the operation of this pump is as follows. The rotor 30 is floated and supported in the radial direction by uncontrolled magnetic bearings 15 provided at both ends of the rotor. By supplying an exciting current to the coil 25b of the electromagnet 25 having the conical control surface 25a provided opposite to the conical axial disk 35 attached to both end surfaces 30a of the rotor 30, the control-type magnetic The bearing 16 floats and supports the rotor 30 at a target position in the axial direction. In a state where the rotor 30 is magnetically levitated by the bearings 15 and 16 and is supported in a non-contact manner, the coil 2
By supplying a current to 2a, the rotor 30 containing the motor rotor 22 rotates without any contact with the stationary side. Then, the liquid in the suction port 11 is pumped toward the discharge port 12 by the pumping action of the screw groove 33 provided on the outer periphery of the rotor 30.

As described above, since the rotor 30 rotates without making any contact with the stationary side 20, the problem of generation of particles (generation of particles) from the sliding portion can be prevented. Therefore, there is no problem that particles are mixed into the liquid to be pumped and mixed into the semiconductor device manufacturing equipment or the like to which the liquid is transferred, which impairs the quality. Further, the flow path of the pumped liquid includes the suction port 11 of the pump, the flow path 16 along the conical surface, the liquid transfer portion around the rotor by the screw groove 33, and the flow along the conical surface again. Via a line 16 it is connected to the outlet 12 of the pump. Therefore, each is arranged substantially linearly in the axial direction. Further, the liquid contact portions on the rotor side and the stationary side of the pump are formed by forming a water-repellent material such as a fluororesin or the like, or a coating of the material.

Since the flow passage is arranged substantially linearly in the axial direction and the narrow assembly gap in the pump is covered with a water-repellent material, the stagnation region and dead water region of the pumped liquid are eliminated. can do. Therefore, the liquid accumulated in the stagnation area / dead water area rots with time and becomes a contaminant, and this liquid gradually seeps into the pumped liquid, mixes into the pumped liquid of the pump, and mixes into the transfer destination device. Can be prevented. Further, since the stagnation area and the dead water area in the flow path are eliminated, the liquid does not accumulate here, and there is no problem that the liquid is solidified and fixed with the lapse of time, so that the maintainability can be improved.

As shown in the figure, the pump of this embodiment has a symmetrical suction port and discharge port, and the pump is reversed to reverse the discharge port and the suction port. The liquid can be transferred in the opposite direction. Thus, when the transfer of a special chemical such as a resist liquid or a liquid for a wafer protective film is stopped, the pump is rotated in the reverse direction to suck back the liquid, so that the inside of the pump is almost empty and the pump is stopped. it can. Therefore, it is possible to reduce solidification and fixation of the chemical solution remaining in the pump when the pump is stopped.

FIGS. 3 to 8 show a liquid feed line pump according to a second embodiment of the present invention. The basic configuration of this pump is the same as that of the liquid feed line pump according to the first embodiment shown in FIGS. That is, it is an in-line screw pump suitable for transferring a special chemical such as a resist solution or a wafer protective film solution used in the manufacture of semiconductor devices.
The control type magnetic bearing 25 includes conical axial disks 35 and 40 attached to both end surfaces of the rotor 30, and has conical control surfaces provided opposite thereto.
25 supports the rotor 30 in the axial direction. The permanent magnets 15b provided at both ends of the rotor 30
And a permanent magnet 15a on the stator side, which is provided on the outer periphery of the rotor, and forms a magnetic bearing 15.
0 is supported in the radial direction. The above-described liquid is pumped from the pump suction port 11 side to the pump discharge port 12 side substantially linearly by a pump action accompanying the rotation of the rotor 30 by the screw grooves 33 and 41 provided on the outer circumference of the rotor or the inner circumference of the stator can. .

Therefore, due to the configuration of the two magnetic bearings 15 and 25, the rotor 30 magnetically levitates and rotates without any contact with the stationary side, so that dust generated by contact between the rotor and the stationary side is completely suppressed. be able to. by this,
It will not contaminate the pumped liquid. In addition, the flow path of the pumped liquid flows only in the axial direction, the structure is in-line type,
And by using a water-repellent material such as a fluororesin or a coating thereof as a material of the liquid contact part constituting the pump,
The pumping liquid can be prevented from permeating into a narrow assembling gap or the like generated by a combination between the parts, and thereby, a structure in which a stagnation region and a dead water region of the pumping liquid can be eliminated.

Here, the liquid sending line pump shown in FIG.
A screw groove 33 is provided on the outer periphery of the rotor similarly to the liquid sending line pump shown in FIG. On the other hand, the liquid feed line pump shown in FIG. 4 is a modified embodiment in which a thread groove 41 is provided on the inner peripheral side of the stator can 23 instead of the above-described thread groove 33 provided on the outer periphery of the rotor. In addition, the liquid feed line pump shown in FIG. 5 shows a modified embodiment in which screw grooves 33 and 41 are provided on both the outer peripheral side of the rotor and the inner peripheral side of the can to improve the performance of the pump by providing screw grooves 33 and 41 having opposite winding ends. ing.

The liquid feed line pump shown in FIGS. 3 to 5 is improved from the liquid feed line pump of the first embodiment shown in FIGS. 1 and 2 in the following points. First, as shown in lines AA in FIGS. 3 to 5 and FIG. 6, a flow path 42 is provided in the stator casing 24 on the outer peripheral side of the radial magnetic bearing 15. Thereby, in the portion where the rotor 30 is supported by the radial magnetic bearing 15, the flow path of the pumped liquid can be provided at substantially the same radial position as the surface of the thread groove on the outer periphery of the rotor, thereby enabling the linear pump A channel can be formed. In addition, by providing a flow path on the outer peripheral side of the radial magnetic bearing in which the permanent magnets 15a are disposed, the size of the flow path can be arbitrarily formed, thereby reducing the resistance loss of the pump.

Second, the BB line in FIGS. 3 to 5 and FIG.
As shown in FIG.
A flow path 43 is provided on the side of the stator core 25 of the axial magnetic bearing opposite to 40. Thereby, the flow path in the axial magnetic bearing portion can be expanded, and the resistance loss can be reduced. Third, C in FIGS.
-As shown in line C and FIG.
Is flattened, an axial displacement sensor 26a is arranged on a rotating shaft facing the conical top, and a flow path 44 is provided outside the sensor. This allows
It is easy to detect the axial position of the rotor 30 by the axial sensor 26a, and the axial sensor 26a can be arranged in the casing 45 without hindering the formation of the linear flow path 44.

[0036]

According to the present invention as described above,
There is provided a liquid sending line pump which is free from the problem of particles or contaminants being mixed in the pumped liquid and is excellent in maintainability.

[Brief description of the drawings]

FIG. 1 is a sectional view taken along a main axis of a liquid sending line pump according to a first embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a sectional view taken along a main axis of a liquid sending line pump according to a second embodiment of the present invention.

FIG. 4 is a sectional view showing a modification of FIG. 3;

FIG. 5 is a sectional view showing another modification of FIG. 3;

FIG. 6 is a sectional view taken along the line AA of FIGS. 3 to 5;

FIG. 7 is a sectional view taken along the line BB of FIGS. 3 to 5;

FIG. 8 is a sectional view taken along the line CC of FIGS. 3 to 5;

[Explanation of symbols]

REFERENCE SIGNS LIST 11 suction port 12 discharge port 15 uncontrolled radial magnetic bearing (gap between magnetic pole faces of permanent magnet) 16 control type axial magnetic bearing (gap between conical axial disk and magnetic pole face of electromagnet) 20 stator 21, 24 casing 22 Motor stator 23 Can 25 Electromagnet 25a Electromagnet pole face 25b Coil 26, 26a Axial sensor 30 Rotor 30a Rotor end face 32 Motor rotor 33, 41 Screw groove 35 Conical axial disk 35a Magnetic pole face 42, 43, 44 Channel

Claims (4)

[Claims] 1. An in-line type screw pump for transferring a liquid, wherein the rotor is radially supported by magnetic bearings provided at both ends of the rotor, and is formed on a conical axial disk attached to both end faces of the rotor. The rotor is supported in the axial direction by a control type magnetic bearing having a conical control surface provided facing each other, the rotor is magnetically levitated by these two bearings and is supported in a non-contact manner, without any contact with the stationary side. A liquid feed line pump which rotates and transfers liquid by a pump action of a screw groove provided on an outer periphery of the rotor. 2. A liquid contact portion on the rotor side and the stationary side of the pump is formed by forming a material having water repellency or a coating of the material, and eliminates a stagnant region or dead water region of pumped liquid. The liquid feed line pump according to claim 1, wherein: 3. The pump according to claim 1, wherein the suction port of the pump, the liquid transfer part by the screw groove, and the discharge port of the pump are arranged substantially linearly in the axial direction, and the liquid transfer part by the screw groove. Along a gap between a conical axial disk surface attached to both end surfaces of the rotor and a control surface of a magnetic bearing provided to face the surface, a suction port and a discharge port of the pump are provided. The liquid feed line pump according to claim 1, wherein the liquid feed line pump is connected in a substantially linear manner in the axial direction. 4. The rotor comprises a cylindrical portion and conical axial disks provided on both end surfaces of the cylindrical portion, and a motor rotor is built in substantially the center of the cylindrical portion. At both ends of the thread groove on the outer periphery of the
The liquid sending line pump according to any one of claims 1 to 3, wherein a permanent magnet constituting a passive magnetic bearing is provided.