JP2007182782A - Pump device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable to transfer extremely highly pure active liquid with preventing metal ion or the like from entering therein. <P>SOLUTION: The pump device includes an impeller 14 attached on an end part of rotary shaft 12 and stored in a pump casing 10, a auxiliary blade 36 preventing transferred liquid pressurized by rotation of the impeller 4 from flowing to a motor side, a seal part 50 including a shaft sealing mechanism 46 arranged in a motor side of the auxiliary blade 36 and operating when the same receives pressure of the transferred liquid, and liming materials 10a, 16a, 16b, 30a, 36a, 38a provided at section touching the transferred liquid. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a rotary pump device for transferring an extremely high-purity active liquid used in a manufacturing process of a semiconductor device or a liquid crystal, and more particularly, during operation, an active liquid such as ultrapure water and The present invention relates to a high-purity liquid transfer pump apparatus that prevents metal ions and other fine particles from entering an active liquid such as ultrapure water to be transferred by insulating the metal part of the pump mechanism from each other.

  As the degree of integration of semiconductor devices and the performance of liquid crystals further increase, the concentration of metal ions remaining in ultrapure water has become a major problem, and now the content of metal ions in ultrapure water is 1 PPT. (1 / trillion) or less is required. This metal ion is expressed by the dissolution behavior of ultrapure water in metals at the wetted parts of all equipment such as pumps, pipes, valves, etc. during the wet process, and particularly has a resistance value of 18.20 MΩ or more. In the highest degree of ultrapure water, it is said that extremely active ion elution of metals and the like occurs.

  In order to solve the above inconvenience, lining material is widely applied to cylinders in contact with ultrapure water in devices such as pumps. However, it is generally difficult to apply the surface treatment of the lining material to the rotary sliding part or the seal part of the pump. Moreover, even if extremely chemically stable high hardness SiC (silicon carbide) is used for the rotary sliding part and the seal part of the pump, the dissolution behavior due to ultrapure water cannot be suppressed.

At present, functional ultrapure water containing a trace amount of ozone (O ₃ ), hydrogen fluoride (HF) and the like is being used for ultrapure water. Such ultra-pure water causes metals and ceramics to be exposed to a larger chemical attack, such as the rotary sliding part of the pump, that is, the metal and ceramics of the liquid contact part in the bearing part and the seal part, etc. It is considered that inconveniences such as corrosion due to elution of selenium are regarded as a further problem.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a high-purity liquid transfer pump device capable of transferring an extremely high-purity active liquid without entering metal ions and the like. And

  The invention according to claim 1 is an impeller attached to the end of the rotating shaft and housed in the pump casing, and an auxiliary for preventing the transfer liquid pressurized by the rotation of the impeller from flowing to the motor side. It has a seal part which has a shaft and a shaft seal mechanism which is arranged on the motor side of the auxiliary blade and operates when the pressure of the transfer liquid is received, and a lining material applied to a portion which comes into contact with the transfer liquid. This is a pump device.

  Thereby, during the pump operation, the transfer liquid that tries to enter the back side of the rotating impeller can be pushed back by the rotational force of the auxiliary blades, the back side of the auxiliary blades can be kept in a dry state, and can be sealed without contact, This makes it possible to apply a lining material to the surface of the auxiliary blade. On the other hand, when the pump is stopped, the transfer liquid at the outlet portion of the impeller enters the back side of the auxiliary blade through the auxiliary blade, and the water that has entered is completely sealed through the shaft seal mechanism. Thus, it is possible to separate the bearing portion from the liquid installation portion via the shaft seal mechanism so that the bearing portion does not come into contact with the liquid.

  According to a second aspect of the present invention, the shaft sealing mechanism has a gap formed between the seal ring attached to the rotating shaft and the seal ring, and contacts the seal ring when receiving the pressure of the transfer liquid. The pump device according to claim 1, further comprising a fixed-side seal plate disposed so as to be in contact with the pump device.

According to a third aspect of the present invention, the auxiliary blade is disposed on the back side of the main plate of the impeller so as to rotate integrally with the rotary shaft at a position where a side plate is disposed between the auxiliary plate and the main plate. The pump device according to claim 1, wherein the pump device is a pump device.
Auxiliary blades may be provided directly on the back side of the impeller, but the sealing effect of the auxiliary blades can be further enhanced by placing the side plate on the back side of the impeller with the side plate positioned therebetween. Can do.

The invention according to claim 4 is the pump according to claim 3, wherein the side plate is fixed by sandwiching the peripheral edge portion of the side plate between the auxiliary blade casing for accommodating the auxiliary blade and the pump casing. Device.
Thereby, it is possible to prevent the lining material from being broken at the joint between the auxiliary blade casing and the side plate and at the joint between the side plate and the pump casing.

  According to the present invention, the back side of the impeller can be sealed in a non-contact manner with a seal portion having a simpler structure than existing seal mechanisms (mechanical seals, gland packings, etc.) during pump operation. During rotation, the seal portion is in a dry state, but there is no concern about seizure or the like. Moreover, elution of metal ions and the like can be prevented by applying a lining material to the entire area of the wetted part. Further, by disposing the bearing portion at a position where no contact is made with the bearing, measures against contact with the bearing are not required.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. Needless to say, the present invention is not limited to the embodiments described herein.
FIG. 1 is a cross-sectional view showing the overall structure of a pump device according to an embodiment of the present invention. Note that the motor is omitted. FIG. 2 is a sectional view showing a shaft sealing mechanism (a combination mechanism of a seal plate and a seal ring) according to the present invention. As shown in FIG. 1, the pump device includes a pump casing 10 and an impeller 14 that is attached to the end of the rotary shaft 12 and accommodated in the pump casing 10. The impeller 14 has a main plate 16 and a plurality of blades 18.

  The rotating shaft 12 is rotatably supported via a bearing portion 24 having a pair of bearings 22 disposed in the bearing body 20, and the rotating shaft 12 of the rotating shaft 12 extending outside from the bearing cover 26 of the bearing body 20. A shaft coupling 28 to the motor side is attached to the end. An auxiliary vane casing 30 and a ground cover 32 are interposed between the pump casing 10 and the bearing body 20, and extend between the bearing body 20 and the ground cover 32 inside the bearing body 20. The end of the ground case 34 is fixed.

  An auxiliary vane 36 is disposed inside the auxiliary vane casing 30, located on the back side of the main plate 16 of the impeller 14, and prevents the transfer liquid pressurized by the rotation of the impeller 14 from flowing to the motor side. . The auxiliary blade 36 is fixed to the rotary shaft 12 with its boss portion sandwiched between the impeller 14 and the sleeve 38, and rotates integrally with the rotary shaft 12. Further, between the ground case 34 and the rotary shaft 12, a shaft having a fixed side seal plate 42 fixed to the ground case 34 with a seal plate presser 40 and a rotary side seal ring 44 attached to the sleeve 38 of the rotary shaft 12. A sealing mechanism 46 is provided, and thereby a seal portion 48 is configured. That is, the seal portion 48 includes the auxiliary blade 36, the shaft sealing mechanism 46, and the space between the auxiliary blade 36 and the shaft sealing mechanism 46 (the sleeve 38 on the rotating shaft 12, the ground case 34, the ground cover 32, the auxiliary blade). A ring-shaped space 50 surrounded by the casing 30 and the seal plate 42.

  The auxiliary blade 36 is a mechanism for scraping back a part of the transferred liquid that has entered the space 50 from the back side of the main plate 16 of the impeller 14 to the vicinity of the outlet portion of the impeller 14. Since it is fixed to the rotating shaft 12, it rotates in synchronization with the rotating shaft 12. Accordingly, since the space 50 is in a dry state during the rotation of the pump, the auxiliary blade 36 can be sealed without contact, and the lining material 36a is applied to the surface of the auxiliary blade 36 as described below. It becomes possible.

  Thus, when the pump is stopped, the transfer liquid discharged from the outlet of the impeller 14 enters the space portion 50 through the back side of the main plate 16 of the impeller 14, and the space portion 50 is the transferred liquid that has entered. It becomes full of water. In this state, when the pump is started, the auxiliary blades 36 fixed to the rotary shaft 12 rotate in synchronization with each other, and the transferred liquid that has entered the space 50 is scraped toward the outlet of the impeller 14 that has entered the space 50. Acts as follows. As a result, the space 50 is in a dry state, and a boundary region between the entering liquid and the dry state is formed in the vicinity of the tip of the auxiliary blade 36, and the boundary region is in a radial direction with respect to the auxiliary blade 36. It shows a widened or narrowed behavior.

  Since the space portion 50 is in a dry state when the pump is activated, the seal plate 42 and the seal ring 44 are not in contact with each other while the shaft seal mechanism 46 is in a dry state. By pressing, the seal plate 42 is pressed against the surface of the seal ring 44 so as to be sealed. That is, as shown in FIG. 2 (a), the seal plate 42 and the seal ring 44 are arranged substantially in parallel with each other in a non-contact state with a slight gap δ. Is in a dry state, the seal plate 42 and the seal ring 44 are not in contact with each other. When the transfer liquid enters the space 50 and the space 50 is filled with the transfer liquid, as shown in FIG. 2B, the seal plate 42 is pushed onto the surface of the seal ring 44 by pushing the transfer liquid. The seal plate 42 comes into contact with the seal ring 44, that is, the gap δ between the seal plate 42 and the seal ring 44 becomes zero (δ = 0), and is sealed here.

  There is a slight gap between the inner peripheral surface of the seal plate 42 and the outer peripheral surface of the sleeve 38 of the rotary shaft 12. Therefore, the seal plate 42 is not in contact with the sleeve 38 while the rotary shaft 12 is rotating. Immediately before the rotation of the rotating shaft 12 decelerates and stops, the force that the auxiliary blade 36 scrapes becomes weak, and when the transfer liquid enters the space 50, the internal pressure of the transfer liquid that has entered the space 50 Thus, the seal plate 42 can be pressed immediately against the seal ring 44 to be sealed immediately.

  In addition, the seal plate 42 is formed of a lining material as described below, and impurities are eluted in the transfer liquid in the space 50 when the internal pressure is applied to the space 50 when the pump is stopped. do not do. However, when starting the pump or immediately before stopping the pump, wear fine powder may be generated due to friction between the rotating seal ring 44 and the seal plate 42. Therefore, a purge pipe 52 may be provided in the ground case 34 so that the transferred liquid in the contaminated space 50 may be positively discharged from the purge pipe 52.

  In this example, the bearing portion 24 is arranged on the motor side of the seal ring 44 so that the bearing portion 24 is separated from the liquid contact portion, and the impeller 14 and the seal portion 48 on the rotating shaft 12 are cantilevered. I try to support it. In this way, by disposing the bearing portion 24 at a position where the bearing portion 24 does not come into contact with the liquid, it is not necessary to take measures against the bearing portion 24 against liquid contact.

  Further, on the back surface side of the main plate 16 of the impeller 14, a flat side plate 54 is disposed between the main plate 16 and the auxiliary blade 36. The side plate 54 is fixed by sandwiching the outer peripheral portion between the pump casing 10 and the auxiliary blade casing 30. In this way, by arranging the side plate 54 between the main plate 16 and the auxiliary blade 36, the sealing effect by the auxiliary blade 36 can be enhanced.

  In this example, anti-corrosion by a lining material made of tetrafluoroethylene / perfluoroalkoxyethylene copolymer resin, vinylidene fluoride resin, or the like is applied to the surface of the portion (wetted part) that contacts the transfer liquid during pump operation. We are processing. That is, the anti-corrosion treatment with the lining material 10 a is applied to the inner peripheral surface of the pump casing 10, the anti-corrosion treatment with the lining materials 16 a and 16 b is applied to the front and back surfaces of the main plate 16 of the impeller 14, and the exposed lining material is applied to the exposed surface of the side plate 54. The rotating shaft 12 facing the auxiliary blade casing 30 is subjected to the anticorrosion processing by 54a, the anticorrosion processing by the lining material 36a on the surface of the auxiliary blade 36, the anticorrosion processing by the lining material 30a on the inner peripheral surface of the auxiliary blade casing 30. The surface of the sleeve 38 is subjected to anticorrosion treatment with a lining material 38a. Note that the side plate 54 itself may be formed of a lining material.

  In this way, by applying an anti-corrosion treatment with the lining material to the wetted part, elution of metal ions and the like from the wetted part can be prevented. In addition, the surface of the auxiliary blade 36 constituting the seal portion 48 is subjected to an anti-corrosion treatment with the lining material 36a, and further, the bearing portion 24 is separated from the liquid contact portion, thereby contacting the transfer liquid during pump operation (contact Anti-corrosion treatment with a lining material can be performed on the entire surface of the liquid portion.

  Furthermore, even when the pump is stopped, the portion (liquid contact portion) that comes into contact with the transferred liquid, that is, the inner peripheral surface of the ground cover 32, the inner peripheral surface of the ground case 34, the inner peripheral surface of the ground cover 32 and the ground case 34. The surface of the sleeve 38 of the rotating shaft 12 and the surface of the seal ring 44 facing each other are preferably subjected to anticorrosion treatment with a lining material. Further, the seal plate 42 is preferably formed of a lining material in order to prevent elution and have an elastic structure.

  The side plate 54 subjected to the anticorrosion treatment with the lining material is sandwiched between the pump casing 10 and the auxiliary vane casing 30 and further arranged to be pressed by the bolt of the pump casing 10 on the basis of the ground cover 32. Thus, it is possible to prevent the lining material from being broken at the joint between the auxiliary blade casing 30 and the side plate 54 and the joint between the side plate 54 and the pump casing 10, and to simplify the structure. it can. Moreover, a screw is cut in the front-end | tip part of the rotating shaft 12, and the screw part can be screwed in and attached to the impeller 14, and a liquid-contact part can be decreased as much as possible.

It is sectional drawing which shows the whole structure of the pump apparatus of embodiment of this invention. It is an enlarged view which expands and shows the shaft seal mechanism shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Pump casing 10a Lining material 12 Rotating shaft 14 Impeller 16 Main plate 18 Blade 22 Bearing 24 Bearing part 30 Auxiliary blade casing 30 Lining material 32 Ground cover 34 Ground case 36 Auxiliary blade 36a Lining material 38 Sleeve 38a Lining material 42 Seal plate 44 Seal Ring 46 Shaft seal mechanism 48 Seal part 50 Space part 54 Side plate 54a Lining material

Claims (4)

An impeller attached to the end of the rotating shaft and housed in the pump casing;
An auxiliary blade that prevents the transfer liquid pressurized by the rotation of the impeller from flowing to the motor side, and a shaft seal mechanism that is disposed on the motor side of the auxiliary blade and that operates when the pressure of the transfer liquid is received. A seal part;
A pump apparatus comprising a lining material applied to a portion in contact with the transfer liquid.   The shaft seal mechanism is a fixed-side seal that is arranged so that a gap is formed between the seal ring attached to the rotating shaft and the seal ring and abuts against the seal ring when receiving the pressure of the transfer liquid The pump device according to claim 1, further comprising a plate.   The auxiliary blade is disposed on the back side of the main plate of the impeller so as to rotate integrally with the rotary shaft at a position where a side plate is disposed between the auxiliary blade and the main plate. Or the pump apparatus of 2.   The pump device according to claim 3, wherein the side plate is fixed by sandwiching a peripheral edge portion of the side plate between the auxiliary blade casing for accommodating the auxiliary blade and the pump casing.

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