WO1996001373A1

WO1996001373A1 - Molecular pump with multiple air suction grooves

Info

Publication number: WO1996001373A1
Application number: PCT/CN1995/000056
Authority: WO
Inventors: Jiguo Chu
Original assignee: Jiguo Chu
Priority date: 1994-07-06
Filing date: 1995-07-05
Publication date: 1996-01-18
Also published as: AU2878695A; CN1115362A

Abstract

The present invention relates to a molecular pump with air suction grooves which are arrayed parallel to each other, wherein a width of the air suction grooves near the rotor shaft is narrow and an air passage between neighbouring suction grooves is wide. Some single-basic air suction units concentrically mounted provide a multistage pump composed in series or parallel connection. The single-basic air suction units concentrically mounted with other molecular pump or rotary mechanical vacuum pump can form a compound vacuum pump with good operation performance. The molecular pump with simple construction can be made conveniently and provides high compression ratio.

Description

TECHNICAL FIELD

The invention relates to a molecular pump theory. Background technique

Chinese patent 92 1 0 1 3 00. 0 describes a molecular pump with multiple drag surfaces. The basic extraction unit provided by this invention has the following disadvantages:

1. The length of the shaft air groove near the shaft is shorter, and the speed of the dragging of the gas molecules is lower.

, Reduces the compression ratio of the suction tank.

2. A small working gap is used between the groove wall and the stationary surface of each parallel suction groove. Therefore, the leakage gas in the working gap between the two outside groove walls is concentrated in the suction groove adjacent to the two outside groove walls. The amplitude reduces the effective compression ratio of the suction tank.

3. The working gap of the movable seal block in the suction tank caused a large amount of gas leakage, which limited the further improvement of the compression ratio. Summary of the Invention

The object of the present invention is to provide a novel molecular pump with a higher compression ratio and less leakage, and a composite vacuum pump composed of such a pump, other molecular pumps and a rotary mechanical vacuum pump.

The molecular pump (referred to as a multi-pull pump) provided in the present invention has at least one set of basic pumping units composed of a plurality of pumping grooves with multiple pumping surfaces connected in parallel. The basic suction unit has a structure similar to that described in Chinese patent 92 1 G 1 3 G (). Fl, and is composed of a moving wheel, a moving seal block, a rotating shaft, a spacer ring, a static wheel, a pump casing and the like.

The moving wheel is composed of several parallel suction grooves along the circumferential direction, and the opening of the suction groove is on the circumferential cylindrical surface, or on the cross section, or on the oblique side. The cross section of the suction tank can be rectangular, curved or other shapes. -Insert a moving seal block into the suction tank. The moving seal block consists of a slightly smaller arc-shaped body with a cross section similar to that of the suction tank. The dynamic sealing block is fixed on the spacer ring, or the pump casing, or a stationary part such as a static wheel. Inlet and exhaust ports are provided on both sides of the dynamic seal block. There is less work between the moving seal block and the suction groove wall

Replacement page (Rules 笫 26 ^) The invention is characterized by:

1. The width of the suction groove near the shaft is narrow.

2. There is a large gas passage between adjacent exhaust grooves, for example, to increase the working gap between the groove wall and the stationary surface between adjacent exhaust grooves, or to set a number of communicating air holes or gaps in the groove wall. Therefore, the leakage gas in the working gap between the two outer tank walls is shared by the parallel suction tanks.

When the moving wheel rotates at a high speed, the above-mentioned basic structure can constitute a set of practically valuable extraction units with multiple operating surfaces.

In the same extraction tank described above, a plurality of movable seal blocks can be installed, and each side of each movable seal block is provided with an air inlet and an exhaust port respectively. In this case, the extraction unit should be regarded as a multi-stage extraction unit.

Sealing stages can be added on both sides of the suction unit.

When using the sealing stage, the movable seal block in the suction tank should be divided into two parts. The isolation space between the two parts of the dynamic seal block is connected to the air inlets of the seal stages on both sides, and the exhaust port of the seal stage is connected to the suction tank. The exhaust port is connected.

The sealing stage can adopt various dynamic sealing structures with a certain suction effect, such as a single-slot multi-pull pump (Chinese patent 921H3G0.I), or the same structure as the basic suction unit described above.

The sealing level greatly reduces the leakage effect caused by the working gap between the two outer tank walls and the moving seal block, and significantly improves the effective compression ratio of the suction tank.

A baffle similar to a stationary blade of a radial turbomolecular pump can be added to the air inlet and the air outlet of the above-mentioned suction unit, thereby further increasing the suction effect. The extraction direction of these baffles should be consistent with the flow direction of the pumped gas.

In the above basic suction unit, the suction slot opening on the circumferential cylinder is abbreviated as a circumferential multi-pull pump, and the suction slot opening on the cross section is abbreviated as a radial multiple drag pump.

Several levels of the above-mentioned basic exhaust units are installed coaxially, and their intake and exhaust ports are connected end-to-end in sequence, which can form a series exhaust, and their intake and exhaust ports can be connected separately to form a parallel exhaust. Several stages of basic pumping units are installed coaxially, in series and parallel, and pumped in parallel near the air intake of the pump, and pumped in series near the pump's exhaust, which can form a molecular pump with better performance.

The above single-stage or multi-stage multi-tow pump suction unit can also be used with other molecular pumps, for example, single-slot multi-tow pump (Chinese patent!) 210Γ3.0), cylindrical double-tow pump (Chinese patent! 1M226.X), Cylindrical single drag pump (H.lw "k molecular pump), disc-shaped double drag pump (ZL-871Dlll (i.6), ά single drag pump (Si e gbaiin molecular pump), or rotary mechanical vacuum pump suction unit Or, they are installed coaxially, in series and parallel, the intake port near the pump is the basic unit of the multi-pull pump, the exhaust port near the pump is the unit of the single-pump pump, or the unit of the rotary mechanical vacuum pump , Composite vacuum pump with better composition performance.

-2-Replacement page (Article 26) Advantages of the invention:

1. The molecular pump proposed by the present invention has relatively high compression.

2. The molecular pump provided by the present invention can be coaxially installed in multiple stages, and can be combined in series and parallel to form a multi-stage molecular pump with excellent performance.

3. The molecular pump proposed by the present invention can also be coaxially installed with other molecular pumps, rotary mechanical vacuum pumps, etc., and combined in series and parallel to form a composite vacuum pump with excellent performance. Overview of the drawings

The invention is further described below with reference to the drawings and embodiments.

Figure 1 is a schematic diagram of a single-stage circumferential multi-pull pump.

Fig. 2 is a sectional view of the single-stage circumferential multi-pull pump in the direction A-A.

Figure 3 is a schematic diagram of a single-stage multi-pull pump with a sealed stage.

Fig. 4 is a sectional view of the single-stage multi-pull pump with seal stage in the direction A-A.

Fig. 5 is a sectional view of a single-stage multi-pull pump with a sealed stage in the direction of B-B.

Fig. 6 is a schematic diagram of a multi-circle multi-pull pump (1).

Fig. ⁷ is a schematic diagram of a multi-circle multi-trailer pump (2).

Fig. 8 is a schematic diagram of a perimeter multi-drag pump.

(Picture!) Is a front view of the multi-pull pump wheel.

Fig. 10 is a cross-sectional view of a multi-pull pump driving wheel.

Fig. 11 is a front view of the static wheel of the multi-pull pump.

Fig. 12 is a cross-sectional view of the stationary pulley of a radial multi-pull pump. Best Mode of the Invention

Embodiment 1: Single-stage circumferential multi-pull pump

This embodiment is shown in FIG. 1, and a cross-sectional view in the A-A direction is shown in FIG. 2.

This embodiment is composed of a rotating shaft (1), a moving wheel (2), a moving seal block (3), a spacer ring (4), and a pump casing (5). The moving wheel is provided with a plurality of (two shown in Fig. 1) suction ducts (6) connected in parallel, and the dynamic sealing block ( ³ ) is fixed on the spacer ring (4). The spacer ring (0 may not be used. At this time, the dynamic seal block (3) is directly fixed on the pump casing (5). The groove wall (-7) between the adjacent suction grooves and the ¾ ring (4), or the pump There is a large gap between the shells (5). Generally, the gap is one-tenth to one-third of the slot width. There are also several inside of each suction tank (. ) The lower groove wall (8), thereby reducing the groove width at that location. Generally, the height of the suction groove is about half the groove depth. The groove walls on both sides (υ and

--3 a replacement sheets ⁽² Rule 6) There is a small working gap between the spacer ring (4), or between the pump casing (5), and between the movable seal block (3) and the suction tank groove wall. Inlet (10) and exhaust (11) are provided on both sides of the movable seal block (3). Ο

Baffles similar to the stationary blades of the radial turbomolecular pump can also be added to the air inlet (lfl) and the exhaust (H). The direction of extraction of these baffles is the same as the direction of the gas being pumped.

Embodiment 2: Single-stage multi-pull pump with sealed stage

This embodiment is shown in FIG. 3, and the cross-sectional views in the A-A and B-B directions are shown in FIGS. 4 and 5.

This embodiment is similar to the first embodiment, except that a two-stage sealing stage (12) consisting of a single-slot multi-pull pump is added to each side of the suction tank, and a dynamic sealing block (3) of the suction tank is divided into two . Two parts movable separation space between the sealing block (13) via a gas passage (14) on both sides of the sealing stages (I ²⁾ of the intake port (is) are connected. The sealed-stage exhaust port (10 is connected to the exhaust port (11) of the suction tank. The dense (12) can also be other dynamic sealing device with a certain suction effect, such as the multiple described in the first embodiment. The pumping unit is composed of a tow pump.

The air inlet (10) and air outlet (11) of the suction tank, and the air inlet (15) and air outlet (16) of the sealed stage can also be added with baffles similar to the stationary blades of the radial turbomolecular pump. The pumping direction of these baffles is consistent with the flow direction of the pumped gas.

Embodiment 3: Compound circumferential multi-pull pump (1)

In this embodiment, several stages of multi-pull pumping units with or without a sealing stage are installed coaxially with several stages of single-slot multi-pump pumping units. The port is the suction unit of the circumferential multi-pull pump, and the exhaust port near the pump is the suction unit of the single-slot multi-pull pump.

FIG. 6 is a schematic diagram of a feasible structure. In the middle near the pump's air inlet (Π) is a set of several sealed stages (1Ό (4 shown in Figure δ)). The circumferential multi-pull pump suction unit (10, with two sides close to each other) The exhaust port (27) of the pump is connected in series with several stages ( ² stages are shown in Fig. 6). Single-slot multi-pump pumping unit () ο

The channel between the stages is set on the pump casing, and the interstage channel near the pump exhaust port (27) can also be set on the spacer ring (4).

Embodiment 4: Compound peripheral multi-pull pump (2)

This embodiment is similar to the third embodiment, except that several stages of coaxial Hoi week molecular pump suction units are added near the exhaust port of the pump. · '

FIG. 7 is a schematic diagram of a feasible structure. In the middle near the pump's air inlet (Π) is a group of several (with ^four seals shown in Figure 7) with a sealing stage ().

18), and several stages are connected in series on both sides (stage 1 is shown in Figure ⁷ ).

-4 Replacement pages (Article ^) Several stages (stage 1 is shown in Figure ⁷ ) Holwk molecular pumping unit (20).

The channels between the various stages are set on the pump casing, and the inter-stage channels that rely on the pump exhaust port (27) can also be set on the spacer ring (υ).

Embodiment 5: Multi-pull pump

As shown in Figure ⁸ , the radial multi-pull pump is composed of a rotating shaft (1), a moving wheel (21), a spacer ( ⁴ ), a pump casing (5), a static wheel (11), and a dynamic seal block (23). The front view and cross-sectional view of (21) are shown in Figure!) And Figure 10 respectively, and the front view and cross-sectional view of static wheel (22) are shown in Figure 11 and Figure 12, respectively.

The moving wheel is provided with a plurality of (two shown in Fig. 8) parallel suction grooves with openings in the cross-sectional direction (

24). Among them, the groove width of the inner suction groove is narrower than that of the outer suction groove. Slot walls between adjacent suction slots (

25) The clearance between the pulley and the static wheel (22) is large, usually one-tenth to one-third of the groove width. There is a small working gap between the two outer groove walls (26) and the static wheel (22). There are several moving seal blocks in each suction tank ( ^two blocks are shown in Fig. 7) (23). The dynamic seal block (2 ³ ) is fixed on the static wheel (11), and there is a small working gap between the movable seal block and the wall of the suction groove. The dynamic seal block (23) is provided with air inlets (28) on both sides respectively. And exhaust port (2ϋ). Inside the moving wheel (21), there are several communication air holes (30) near the shaft.

Two sets of moving seal blocks (23) divide the suction tank into two sets of suction units. The two gas passages (31) on the static wheel (22) respectively connect the two exhaust ports (29) and the air holes (30), so that the two sets of suction grooves form parallel suction.

Baffles similar to the stationary blades of the axial-flow turbomolecular pump can be added to the air inlet () and the exhaust (29), and the direction of extraction of these baffles is the same as the direction of the gas being pumped.

Example 6: Compound Vacuum Pump

The composite vacuum pump is coaxially installed by the above-mentioned various molecular pumps and the rotary mechanical vacuum pump suction unit. It is combined in series and parallel. The intake port near the pump is the suction unit of the molecular pump. . Industrial applicability

The invention is mainly used in the fields of vacuum coating, integrated circuit manufacturing, manufacturing of electric vacuum devices such as electric light sources, kinescopes, accelerators and plasma technology.

Claims

Request for Rights

What is claimed is: 1. A molecular pump comprising at least one set of basic suction units consisting of a plurality of suction slots of a plurality of drag surfaces connected in parallel. The basic suction unit comprises a moving wheel, a moving seal block, a rotating shaft, a spacer ring, a static wheel and Pump casing and other components;

The moving wheel is composed of several parallel suction grooves along the circumferential direction. The suction grooves are opened on the circumferential cylindrical surface, or on the cross section, or on the oblique side. The cross section of the suction groove can be rectangular, curved or other. Shape; insert a moving seal block in the suction groove, the dynamic seal block is similar to the suction groove but has a slightly smaller arc-shaped body; the dynamic seal block is fixed to the spacer ring, or the pump housing, or a stationary part such as a static wheel There is a small working gap between the movable seal block and the wall of the suction groove; there are air inlets and exhaust ports on both sides of the movable seal block;

It is characterized by the above-mentioned basic suction unit:

(1) the width of the suction groove near the rotating shaft is narrow;

(2) A large gas passage is provided between two adjacent shaft gas grooves.

The molecular pump according to claim 1, characterized in that, in the basic axial air unit, a gap between a groove wall between two adjacent parallel suction grooves and a stationary surface of the suction groove is larger than that of the groove walls on both sides and The gap between the stationary surfaces of the suction pump.

3. The molecular pump according to claim 1, characterized in that in the basic pumping unit, a plurality of communication air holes or gaps are provided on a tank wall between two adjacent pumping tanks in parallel. -

The molecular pump according to claim 1, characterized in that in the basic pumping unit, a plurality of lower ones are added to the bottom of the pumping groove (that is, near the rotating shaft) of the pumping groove which is opened on a circumferential cylinder surface. The groove wall thus reduces the groove width at this portion.

5. The molecular pump according to claim 1, characterized in that, in the basic pumping unit, a plurality of movable seal blocks are installed in the same pumping groove, and each side of each movable seal block is provided with an air inlet and a Breath.

The molecular pump according to claim 1, characterized in that a sealing stage is additionally provided on both sides of the basic suction unit, and a dynamic sealing block in the suction tank is divided into two parts, and an isolation space therebetween and a sealing stage are provided. The air ports are connected, and the sealed-level exhaust port is connected to the exhaust port of the extraction unit. · '

The molecular pump according to claim 6, characterized in that said sealing stage adopts a single-slot multi-pull basic pumping unit.

The molecular pump according to claim 1, characterized in that a baffle similar to a turbine molecular pump stationary blade is added to the air inlet or exhaust port of the basic suction unit, and the baffling direction and pumping of the baffle Angry

-6-

Replace page (decision 20th) The body flows in the same direction.

9. The molecular pump according to claim 6, characterized in that a baffle plate similar to the turbine blade of the turbomolecular pump is added to the air inlet or exhaust port of the sealed stage. The gas flows in the same direction.

The molecular pump according to claim 1, characterized in that the basic suction unit is coaxially mounted with several stages of single-slot multi-pull pumps, and the intake port near the pump is the basic suction unit, close to The exhaust port of the pump is connected with several stages of single-slot multi-pump pumping units in series. The channels between the stages are set on the pump casing, and the inter-stage channels near the pump exhaust port (27) can also be set on the spacer ring (4 ) On.

Π. The molecular pump according to claim 6, characterized in that the basic suction unit is coaxially installed with several stages of single-slot multi-pull pumps, and the inlet of the pump is the basic suction unit. The pump exhaust port is connected with several stages of single-slot multi-pump pumping units in series. The channels between the stages are set on the pump casing. The interstage channels near the pump exhaust port (27) can also be set on the spacer ring (0 .

12. The molecular pump according to claim 11, characterized in that the molecular pump is provided with several stages of coaxially mounted, serially pumped Holwck molecular pump units near the pump exhaust port.

13. The molecular pump according to claim 12, characterized in that said molecular pump is provided with baffles similar to the stationary blades of the turbo molecular pump near the pump air inlet, and the baffling direction of these baffles and the flow of the pumped gas The direction is the same.

The molecular pump according to claim 10, characterized in that a coaxial and serial rotary mechanical vacuum pump suction unit is added to the exhaust port of the pump.

-7 1 Replacement (Article 26)