KR20230119761A - Turbo molecular pump comprising buffer chamber - Google Patents

Abstract

The present invention relates to a turbo molecular pump, and according to one aspect of the present invention, a turbo unit including a rotating blade and a stator and exhausting gas molecules, disposed downstream of the turbo unit and exhausting gas molecules through a screw groove flow path unit A turbo molecular pump includes a drag unit for exhausting, an exhaust pipe connected to the drag unit, and a buffer chamber movably connected to a connection passage connecting the turbo unit and the drag unit.

Description

Turbo molecular pump comprising buffer chamber

The present invention relates to a turbo molecular pump having a buffer chamber.

The turbo molecular pump is a vacuum pump device used for high vacuum and high-speed exhaust in various manufacturing industries by rotating multi-stage rotor blades at high speed.

The turbo molecular pump has a structure in which a rotor rotates at high speed inside a housing having an intake port and an exhaust port. The stator is installed in multiple stages inside the housing, and on the other hand, rotating blades are radially provided on the rotor, and the rotating blades are installed in multiple stages.

In this structure, when the rotor rotates at high speed, gas is drawn into the intake port by the action of the rotating blades and the stator, and is exhausted through the exhaust port.

The turbo molecular pump includes a turbo part including rotating blades and a stator, and a drag part including a screw groove passage part downstream of the turbo part, from an intake port to an exhaust port.

On the other hand, in the turbo molecular pump, since the region between the turbo unit and the drag unit is a region in which the mechanism of the rotor rotating unit is switched when process gas is loaded, the pressure temporarily rises and exhaust performance may deteriorate.

That is, the pressure between the turbo part area and the drag part area temporarily increases due to the process gas flow rate load, so that solid by-products of the process gas may be generated.

Therefore, due to the generation of process by-products, contact may occur between the rotating part of the rotor and the stator, and thus exhaust performance may be deteriorated or durability of the pump may be reduced.

An object of the present invention is to provide a turbo molecular pump capable of preventing solid by-products of a process gas by providing a buffer chamber for pressure relief between a turbo unit and a drag unit.

In order to solve the above problems, according to one aspect of the present invention, a turbo unit including a rotating blade and a stator, exhaust gas molecules is disposed downstream of the turbo unit and exhaust gas molecules are exhausted through a screw groove passage unit. A turbo molecular pump includes a drag unit, an exhaust pipe connected to the drag unit, and a buffer chamber movably connected to a connection passage connecting the turbo unit and the drag unit.

As described above, the turbo molecular pump related to an embodiment of the present invention has the following effects.

A buffer chamber may be provided in a flow area connecting the turbo unit and the drag unit to prevent a pressure between the turbo unit area and the drag unit area from temporarily increasing due to a process gas flow rate load.

In addition, the durability of the pump can be improved by relieving the pressure and preventing process by-products by locating a buffer chamber, which is a buffer space for relieving the pressure, between the screw groove flow path and the guide spacer.

In addition, the buffer chamber provides an extra space to block the direct cooling conduction of the screw groove flow path and the thermostat (water cooling device), so that the temperature of the screw groove flow path is maintained higher than the sublimation temperature of the process gas, and as a result, the solid By-product formation can be avoided.

1 is a schematic diagram showing a turbo molecular pump related to an embodiment of the present invention.
2 is a cutaway perspective view of a drag unit in a state in which the turbo unit is separated.
Figure 3 is a plan view of Figure 2;
4 and 5 are enlarged views of the illustrated buffer chamber area of FIG. 1 .

Hereinafter, a turbo molecular pump having a buffer chamber according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

In addition, regardless of the reference numerals, the same or corresponding components are assigned the same or similar reference numerals, and duplicate descriptions thereof will be omitted. For convenience of description, the size and shape of each component shown is exaggerated or reduced. It can be.

1 is a schematic diagram showing a turbo molecular pump 1 related to an embodiment of the present invention.

The turbo molecular pump according to this document may be installed in, for example, a semiconductor or display manufacturing apparatus, and may be used when discharging a process gas from a vacuum chamber.

Referring to FIG. 1 , the turbo molecular pump 1 includes a case 10 having an intake port 11 and an exhaust port 12 and a rotating shaft 20 disposed in the case. The case 10 constitutes an external body of the turbo molecular pump 1 and may have a substantially cylindrical shape. In addition, the case 10 may have a structure in which a plurality of housings, for example, two or more housings 13 and 14 are assembled.

In addition, a gas transport unit for transporting gas molecules is provided inside the case 10 to exhaust gas molecules, and the gas transport unit includes a turbo unit T and a drag unit D. The turbo unit T includes rotating blades 31 to 37 rotatably supported by an axis and a stator 40 fixed in the case 10 .

Referring to FIG. 1, the turbo molecular pump 1 includes rotating blades 31 to 37 and stators 40: 41 to 47, and the turbo molecular pump 1 includes rotating blades 31 to 37. A turbo unit (T) that exhausts gas molecules toward the drag unit as it rotates, and an exhaust that is disposed downstream of the turbo unit (T) along the exhaust direction of the gas molecules and exhausts the gas molecules through the screw groove passage part (50). It includes a drag unit (D).

In addition, the turbo part (T) is supported on the rotating shaft 20, and the rotor unit 30 including a plurality of stages of rotating blades 31 to 37 along the axial direction (y-axis direction) of the rotating shaft 20 include Each of the plurality of stages of rotating blades extends along the radial direction (x-axis direction) with respect to the rotating shaft 20 .

In addition, the stator 40 may include a ring-shaped inner ring, an outer ring disposed concentrically with the inner ring and having a larger diameter than the inner ring, and a plurality of fixed blades connecting the inner ring and the outer ring. In addition, the stator 40 is composed of a plurality of stages along the axial direction (y-axis direction) of the rotating shaft 20, and each is positioned between two adjacent rotating blades along the axial direction (y-axis direction) of the rotating shaft 20. will be located That is, along the axial direction (y-axis direction) of the rotating shaft 20, the rotating blade, the stator, the rotating blade, and the stator are sequentially arranged. 1 shows a case in which a total of seven stages of rotating blades and stators are disposed, the present invention is not limited thereto.

In addition, the turbo unit T includes a spacer 90 arranged to maintain a gap between two adjacent stators along the axial direction (y-axis direction) of the rotation shaft 20 .

In addition, the turbo part T may further include a guide 901 that surrounds the stator and the spacer together on the outside. The guide 901 may be provided to surround a plurality of stators and a plurality of spacers disposed adjacent to each other along the axial direction (y-axis direction) of the rotation shaft 20 from the outside.

In addition, the case 10 of the turbo molecular pump 1 includes a first housing 13 surrounding the turbo part T and a second housing surrounding the drag part D and equipped with an exhaust pipe 80. (14) included. In addition, the turbo molecular pump 1 includes a guide spacer 60 disposed between the first and second housings 13 and 14 on which the turbo unit T is seated. A lowermost spacer 90 along the axial direction of the rotation shaft 20 may be seated on the guide spacer 60 .

In addition, the guide 901 positioned at the lowest end along the axial direction of the rotation shaft may be disposed in the first housing 13 and partially inserted into the guide spacer 60 so that the position thereof may be fixed.

In addition, in the turbo molecular pump 1, the rotor unit 30 is fixed to the rotating shaft 20 and rotates together, and the rotating shaft 20 may be rotated by a motor. In particular, the turbo molecular pump 1 supports the rotor unit 100 in a non-contact manner with magnetic bearings when the rotor unit 100 rotates, and in a rotating state, two radial magnetic bearings disposed close to the outer circumferential surface of the rotating shaft 20 and It is supported in a non-contact state in a magnetic levitation state by a pair of axial magnetic bearings disposed above and below the flange portion integrally formed with the rotating shaft 20.

In addition, the turbo molecular pump 1 includes a touchdown bearing 200, which includes a radial magnetic bearing and an axial magnetic bearing with the rotary shaft 20 when the rotary shaft 20 stops and when the control is abnormal. It is a rolling bearing to protect it from contact damage.

The distance between the touchdown bearing 200 and the outer circumferential surface of the rotary shaft 20 is smaller than the distance between each magnetic bearing and the outer circumferential surface of the rotary shaft 20 . In this structure, in a state in which the rotating shaft 20 is rotationally supported by the magnetic bearing in a magnetic levitation state, the rotating shaft 20 maintains a non-contact state with respect to the touchdown bearing 200, but when the rotating shaft 20 is stopped , or when the control is abnormal due to the action of an external force, the rotating shaft 20 contacts the touchdown bearing 200 before contacting each magnetic bearing and is supported for rotation.

In addition, the touchdown bearing 200 may include an inner ring provided to contact the rotation shaft 20 when the rotation shaft stops rotating or when control is abnormal, a plurality of balls supported by the inner ring, and an outer ring surrounding the balls. In this case, the inner ring It may be provided to perform the function of this rotating wheel. The balls are provided in plurality, and may include ferromagnetic balls (eg, stainless steel balls) and ceramic balls.

The touchdown bearing 200 may be disposed at upper and lower ends of the rotation shaft in the axial direction, respectively. In addition, it includes an upper housing 16 supporting the outer ring of the touch down bearing 200, and is inserted into the upper housing 16. It may include a magnetized member 300 provided to pull the ball toward the outer race. The magnetized member 300 is a member processed to have a force to attract a magnetic material, and may include a permanent magnet. Also, reference numeral 17 denotes a lower housing coupled to the upper housing.

FIG. 2 is a cutaway perspective view of the drag unit in a state in which the turbo unit is separated, FIG. 3 is a plan view of FIG. 2 , and FIGS. 4 and 5 are enlarged views of the illustrated buffer chamber area of FIG. 1 .

Referring to FIGS. 1 and 2 , the turbo molecular pump 1 enables fluid movement with an exhaust pipe 12 connected to the drag unit D and a connection passage connecting the turbo unit T and the drag unit D. It includes a buffer chamber 100 connected to it.

The buffer chamber 100 is disposed so that at least some of the gas molecules that have passed through the turbo part T are introduced into the buffer chamber 100 before being introduced into the drag part D. That is, the buffer chamber 100 is provided on a connection passage between the turbo part T and the drag part D, and the pressure between the turbo part T and the drag part D is increased by the process gas flow rate load. Temporary increase can be prevented. That is, in the present invention, when the pump is combined with other mechanisms such as the turbo unit (T) and the drag unit (D), the turbo unit (T) and the drag unit are used to relieve the momentary high pressure in the area where the rotation mechanism is changed. A buffer chamber 100 for buffering is provided in the connection passage area between the parts D.

The connection passage refers to a space between an area below the lowermost blade 37 of the rotary shaft 20 in the axial direction and an inlet of the screw groove passage part 50 .

In one embodiment, the buffer chamber 100 may be provided between the guide spacer 60 and the drag unit (D). Specifically, the buffer chamber 100 may be provided between the guide spacer 60 and the screw groove passage part 50 .

Referring to FIGS. 2, 4, and 5 , the inlet I of the buffer chamber 100 may be formed by separating a portion of the guide spacer 60 from the drag part D. Specifically, the inlet (I) of the buffer chamber 100 may be formed such that a partial area of the guide spacer 60 is spaced apart from the screw groove flow path portion 60 . The interval (width) of the inlet (I) may be appropriately set in consideration of the processing capacity of the turbo unit and the drag unit and the number of stages of the turbo unit. For example, the interval (width) of the inlets (I) may be about 0.1 to 10 mm, and the interval (width) of the inlets (I) may be about 0.5 to 5 mm.

In addition, a temperature controller 70 may be disposed between the guide spacer 60 and the second housing 14 in the turbo molecular pump 1 . In addition, the temperature control device may be inserted into the guide spacer (60). In one embodiment, the temperature control device 70 is a device for cooling, and may be, for example, a water cooling tube.

In this structure, when the water cooling pipe operates, the buffer chamber 100 is positioned between the water cooling pipe and the screw groove passage 50 to prevent the cooling effect from being directly transmitted to the screw groove passage 50. can Therefore, the screw groove passage 50 can maintain a temperature higher than the sublimation curve of the process gas in order to prevent the formation of solid by-products.

In addition, since the water cooling pipe is located adjacent to the buffer chamber 100, the process gas entering the inside of the buffer chamber 100 can be sublimated into a solid by-product, and the buffer chamber 100 also serves to collect the solid by-product. can

Referring to FIGS. 2 and 3 , the buffer chamber 100 may extend along the rotational direction R of the rotational blades 31 to 37 based on the central axis of the rotational axis. For example, the buffer chamber 100 may be a ring-shaped space continuously formed along the rotation direction of the rotary blades 31 to 37 .

In addition, the buffer chamber 100 may be provided such that a cross-sectional flow area increases at least in part along a direction from the inlet side I to the exhaust pipe 80 side.

The height H of the buffer chamber along the central axis direction of the rotary shaft 20 of the turbo unit may be smaller than the height of the drag unit D. Specifically, the height H of the buffer chamber in the direction of the central axis of the rotating shaft 20 may be smaller than the height of the screw groove flow passage 50 .

In addition, the width L of the buffer chamber 100 may increase toward the inside of the chamber from the side of the inlet I. As shown in FIG. 4 , the cross section of the buffer chamber 100 may be a polygonal shape or, differently from this, a circular or elliptical shape.

Referring to FIG. 5 , the turbo molecular pump 1 may include a bypass passage 110 connecting the buffer chamber 100 and the exhaust pipe 80 .

The airflow introduced into the buffer chamber 100 may flow to the exhaust pipe 80 through the bypass passage 110 .

In addition, the turbo molecular pump 1 may include a check valve 120 disposed in the bypass passage 110 to allow only flow in a direction from the buffer chamber 100 toward the exhaust pipe 80 . The check valve 120 is to prevent reverse flow in the bypass flow path 110, allows only flow in the direction from the buffer chamber 100 toward the exhaust pipe 80, and flows from the side of the exhaust pipe 80 to the buffer chamber 100. ) is provided so as not to allow flow in the direction toward.

Preferred embodiments of the present invention described above have been disclosed for illustrative purposes, and those skilled in the art having ordinary knowledge of the present invention will be able to make various modifications, changes, and additions within the spirit and scope of the present invention, and such modifications and changes and additions are intended to fall within the scope of the following claims.

1: turbo molecular pump
10: case
100: buffer chamber

Claims (12)

a turbo unit including a rotating blade and a stator and exhausting gas molecules;
an exhaust drag unit disposed downstream of the turbo unit and exhausting gas molecules through the screw groove passage unit;
An exhaust pipe connected to the drag unit; and
A turbo molecular pump comprising a buffer chamber movably connected to a connection flow path connecting the turbo part and the drag part. According to claim 1,
The buffer chamber is arranged so that at least some of the gas molecules that have passed through the turbo unit are introduced into the buffer chamber before being introduced into the drag unit. According to claim 1,
The buffer chamber is a turbo molecular pump extending along the direction of rotation of the rotating blade. According to claim 1,
The buffer chamber is a turbo molecular pump having a ring shape continuously formed along the rotational direction of the rotating blade. According to claim 1,
A turbo molecular pump further comprising a bypass passage connecting the buffer chamber and the exhaust pipe. According to claim 1,
The turbo molecular pump of According to claim 5,
The turbo molecular pump further comprising a check valve disposed in the bypass passage to allow only flow in a direction from the buffer chamber toward the exhaust pipe. According to claim 1,
A first housing surrounding the turbo unit;
a second housing surrounding the drag part and equipped with an exhaust pipe; and
The turbo unit is seated and further includes a guide spacer disposed between the first and second housings,
The buffer chamber is a turbo molecular pump provided between the guide spacer and the drag unit. According to claim 8,
A turbo molecular pump in which a thermostat is disposed between the guide spacer and the second housing. According to claim 9,
The thermostat is a turbo molecular pump inserted within the guide spacer. According to claim 8,
The inlet of the buffer chamber is a turbo molecular pump formed by separating a part of the guide spacer from the drag unit. According to claim 1,
A turbo molecular pump in which the height of the buffer chamber along the direction of the central axis of the turbo part is smaller than the height of the drag part.

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