EP4062068A1

EP4062068A1 - Scroll pump

Info

Publication number: EP4062068A1
Application number: EP20801396.1A
Authority: EP
Inventors: Peter Charles LAMB; Michael Andrew Galtry
Original assignee: Edwards Ltd
Current assignee: Edwards Ltd
Priority date: 2019-11-19
Filing date: 2020-11-03
Publication date: 2022-09-28
Anticipated expiration: 2040-11-03
Also published as: EP4062068B1; WO2021099759A1; CN114667393A; GB201916841D0; GB2589104A

Abstract

A scroll pump (100, 200) comprising a first scroll (130) with a cooling conduit (170) extending therethrough and a fan (160) configured to blow cooling gas towards the first scroll (130), wherein the cooling conduit (170) is configured to receive cooling gas blown by the fan (160) and convey the received cooling gas through the first scroll (130).

Description

SCROLL PUMP

FIELD OF THE INVENTION

The present invention relates to scroll pumps.

BACKGROUND

Scroll pumps are a known type of pump used in various different industries (e.g. in R&D laboratories). Scroll pumps operate by using the relative motion of two intermeshed "scrolls" to pump fluid.

In scroll pumps, a significant amount of heat is generated during operation. Thus, it is desirable to provide ways of cooling the scroll pump.

SUMMARY

According to a first aspect, there is provided a scroll pump comprising a first scroll with a cooling conduit extending therethrough, and a fan configured to blow cooling gas towards the first scroll, wherein the cooling conduit is configured to receive cooling gas blown by the fan and convey the received cooling gas through the first scroll.

The scroll pump may further comprise a second scroll intermeshed with the first scroll, wherein the second scroll is located further away from the fan than the first scroll.

One of the first and second scrolls is a fixed scroll and the other one of the first and second scrolls is an orbiting scroll.

The scroll pump may further comprise a drive shaft coupled to the fan and at least one of the first and second scrolls, wherein the shaft is configured to rotate to drive the blowing of the fan and the orbiting of orbiting scroll.

The scroll pump may further comprise a cowl extending around the first and second scrolls, the cowl being configured to direct cooling gas exiting the cooling conduit around the first and second scrolls. The cowl may be attached to the fixed scroll.

The cowl may comprise one or more surface features selected from the following group of surface features: one or more ridges, one or more grooves, one or more lattice structures, one or more fins, one or more folds.

The cooling conduit may be defined by a surface and the surface comprises one or more surface features selected from the following group of surface features: one or more ridges, one or more grooves, one or more lattice structures, one or more fins, one or more folds.

The surface defining the cooling conduit may be a surface of an insert disposed within the first scroll.

The first scroll may be formed from a single piece of material.

The first scroll may be formed from two pieces of material attached to each other.

One of the two pieces may comprise a spiral wall of the first scroll and the other one of the two pieces may comprise an inlet passage of the cooling conduit and an outlet passage of the cooling conduit.

The cooling conduit may extend from an axially facing surface of the first scroll to a circumferential surface of the first scroll.

The scroll pump may comprise a plurality of cooling conduits, each of the plurality of cooling conduits being configured to receive cooling gas blown by the fan and convey the received cooling gas through the first scroll.

Each of the plurality of cooling conduits may extend from an axially facing surface of the first scroll to a circumferential surface of the first scroll.

According to a second aspect there is provided a vacuum pumping system comprising a scroll pump according to the first aspect.

BRIEF DESCRIPTION OF DRAWINGS

Figure 1 is a schematic illustration (not to scale) showing a cross- sectional view of a scroll pump; Figure 2 is a schematic illustration (not to scale) showing a cross- sectional view of another scroll pump;

Figure 3 is a schematic illustration (not to scale) showing a cross- sectional view of a two-piece structure for a scroll of a scroll pump; Figures 4 and 5 are a schematic illustrations (not to scale) showing perspective views of structures which may be formed on an internal surface of the two-piece structure;

Figures 6A to 6D are schematic illustrations (not to scale) showing perspective views of examples of inserts which may be inserted in the fixed scroll of the scroll pump.

DETAILED DESCRIPTION

Figure 1 is a schematic illustration (not to scale) showing a scroll pump 100 in accordance with an embodiment of the invention.

The scroll pump 100 comprises a casing 110, an orbiting scroll 120, a fixed scroll 130, a drive shaft 140, a motor 150 and a fan 160. It will be appreciated that the scroll pump 100 also comprises various other components, but these will not be described for the sake of brevity. The scroll pump 100 may be used as part of a vacuum pumping system, e.g. in a R&D laboratory.

In this embodiment, the casing 110 and the fixed scroll 130 together define an overall housing of the scroll pump 100 within which other components of the scroll pump 100 are located.

The orbiting scroll 120 is located within the overall housing of the scroll pump 100 and intermeshed with the fixed scroll 130. The orbiting scroll 120 is configured to orbit relative to the fixed scroll 130 to pump fluid from an inlet (not shown) of the scroll pump 100 to an outlet (not shown) of the scroll pump 100. The orbiting scroll 120 comprises a first base 122 and a first spiral wall 124 extending from the base 122. The fixed scroll 130 comprises a second base 132 and a second spiral wall 134 extending from the second base 132. The first and second spiral walls 124, 134 are intermeshed with each other to define a space therebetween which is used by the scroll pump 100 during operation to pump fluid. The details of the physical mechanism by which fluid is pumped by the orbiting of the orbiting scroll 120 relative to the fixed scroll 130 is well known and will not be described herein for the sake of brevity.

In this embodiment, the orbiting and fixed scrolls 120, 130 are each formed as a single-piece structure. The drive shaft 140, motor 150 and fan 160 are located within the overall housing of the scroll pump 100. The drive shaft 140 is coupled to both the orbiting scroll 120 and the fan 160. More specifically, the drive shaft 140 is coupled at a first end thereof to the orbiting scroll 120 and at a second, opposite end thereof to the fan 160. The motor 150 is configured to actuate the drive shaft 140 to cause rotation the drive shaft 140. The rotation of the drive shaft 140 drives both the orbiting of the orbiting scroll 120 and rotation of the fan 160. The rotation of the fan 160 blows gas (e.g. air) through (and/or across) the scroll pump 100 towards the fixed and orbiting scrolls 120, 130 to cool the fixed and orbiting scrolls 120, 130 (as shown by arrows 162). The fixed scroll 130 comprises a plurality of cooling conduits or galleries

170 which extend through the fixed scroll 130. Each cooling conduit 170 is configured to receive cooling gas blown by the fan 160, convey the received cooling gas through the fixed scroll 130 (as shown by arrows 164), and output the cooling gas out of the fixed scroll 130. In more detail, each cooling conduit 170 comprises an inlet 172 at which the cooling gas is received into the cooling conduit 170 and an outlet 174 at which the cooling gas is output out of the fixed scroll 130.

In this embodiment, each cooling conduit 170 extends from an axially facing surface of the fixed scroll 130 to a circumferential surface of the fixed scroll 120. The axially facing surface faces away from the orbiting scroll 120.

Advantageously, the directing of gas through the fixed scroll 130 in the manner described above tends to bring the cooling gas closer to the orbiting scroll 120 and thus tends to provide for improved cooling of the orbiting scroll 120 compared to if the cooling conduits 170 were not present. For example, if the cooling conduits 170 were not present, then all of the cooling gas would simply impinge on the axially facing surface of the fixed scroll 120 and be directed away from the scroll pump 100 in a direction parallel to the axially facing surface (i.e. a radial direction) and thus would not flow close to the orbiting scroll 120. Furthermore, the directing of cooling gas in the manner described above tends to improve the cooling of the fixed scroll 130 because the cooling gas makes contact with a relatively large surface area and the cooling is more evenly dispersed through the fixed scroll 130.

Figure 2 is a schematic illustration (not to scale) showing a cross- sectional view of a scroll pump 200 in accordance with another embodiment.

The scroll pump 200 comprises a casing 210, an orbiting scroll 220, a fixed scroll 230, a drive shaft 240, a motor 250 and a fan 260. It will be appreciated that the scroll pump 200 also comprises various other components, but these will not be described for the sake of brevity. The scroll pump 200 may be used as part of a vacuum pumping system, e.g. in a R&D laboratory.

In this embodiment, the casing 210 and the fixed scroll 230 together define an overall housing of the scroll pump 200 within which other components of the scroll pump 200 are located.

The orbiting scroll 220 is located within the overall housing of the scroll pump 200 and intermeshed with the fixed scroll 230. The orbiting scroll 220 is configured to orbit relative to the fixed scroll 230 to pump fluid from an inlet (not shown) of the scroll pump 200 to an outlet (not shown) of the scroll pump 200. The orbiting scroll 220 comprises a first base 222 and a first spiral wall 224 extending from the base 222. The fixed scroll 230 comprises a second base 232 and a second spiral wall 234 extending from the second base 232. The first and second spiral walls 224, 234 are intermeshed with each other to define a space therebetween which is used by the scroll pump 200 during operation to pump fluid. The details of the physical mechanism by which fluid is pumped by the orbiting of the orbiting scroll 220 relative to the fixed scroll 230 is well known and will not be described herein for the sake of brevity.

In this embodiment, the orbiting and fixed scrolls 220, 230 are each formed as a single-piece structure. The drive shaft 240, motor 250 and fan 260 are located within the overall housing of the scroll pump 200. The drive shaft 240 is coupled to both the orbiting scroll 220 and the fan 260. More specifically, the drive shaft 240 is coupled at a first end thereof to the orbiting scroll 220 and at a second, opposite end thereof to the fan 260. The motor 250 is configured to actuate the drive shaft 240 to cause rotation the drive shaft 240. The rotation of the drive shaft 240 drives both the orbiting of the orbiting scroll 220 and rotation of the fan 260. The rotation of the fan 260 blows gas through (and/or across) the scroll pump 200 towards the fixed and orbiting scrolls 220, 230 to cool the fixed and orbiting scrolls 220, 230 (as shown by arrows 262).

The fixed scroll 230 comprises a plurality of cooling conduits or galleries 270 which extend through the fixed scroll 230. Each cooling conduit 270 is configured to receive cooling gas blown by the fan 260, convey the received cooling gas through the fixed scroll 230 (as shown by arrows 264), and output the cooling gas out of the fixed scroll 230. In more detail, each cooling conduit 270 comprises an inlet 272 at which the cooling gas is received into the cooling conduit 270 and an outlet 274 at which the cooling gas is output out of the fixed scroll 230.

In this embodiment, each cooling conduit 270 extends from an axially facing surface of the fixed scroll 230 to a circumferential surface of the fixed scroll 220. The axially facing surface faces away from the orbiting scroll 220.

In this embodiment, the scroll pump 200 further comprises a cowl 280 extending around the fixed and orbiting scrolls 220, 230. The cowl 280 is configured to direct cooling gas which has been output from the cooling conduits 270 along the exterior of the overall housing of the scroll pump 100, past the orbiting scroll 220, and out of an exit hole located in line with the drive shaft 240 (as shown by arrows 266). The cowl 280 is annular and extends around the circumference of the fixed and orbiting scrolls 220, 230. Although not shown in Figure 2, the cowl 280 is attached to the fixed scroll 230.

The cowl 280 comprises one or more surface features (e.g. moulded surface features) on a surface of the cowl 280 which faces towards the fixed and/or orbiting scrolls 220, 230. In general, the one or more surface features may be any surface feature which acts to direct gas flow, modify gas velocity, induce turbulence or attenuate noise from gas flow. For example, the one or more surface features may comprise one or more of the following: one or more ridges, one or more grooves, one or more lattice structures, one or more fins, one or more folds.

Advantageously, the directing of gas through the fixed scroll 230 in the manner described above tends to bring the cooling gas closer to the orbiting scroll 220 and thus tends to provide for improved cooling in a similar manner to that described above for the embodiment of Figure 1. Additionally, the presence of the cowl 280 brings the cooling gas flow even closer to the orbiting scroll 220 and thus tends to provide for further improved cooling of the orbiting scroll 220.

Figure 3 is a schematic illustration (not to scale) showing a cross- sectional view of a two-piece structure which may be used for the fixed scroll 130, 230 of the embodiments of Figures 1 and 2.

With this two-piece structure, the fixed scroll 130, 230 comprises a first piece 310 and a second piece 320. The first piece 310 comprises the second spiral wall 134, 234 and a first part of the second base 132, 232, whilst the second piece 320 comprises a second part of the second base 132, 232, one or more inlet passages 330a of the cooling conduit 170, 270, and one or more outlet passages 330b of the cooling conduit 170, 270. The one or more inlet passages 330a are configured to receive the cooling gas blown by the fan into the fixed scroll 130, 230, and the one or more outlet passages 330b are configured to output the received cooling gas out of the fixed scroll 130, 230. The first and second pieces 310, 320 are each manufactured separately and subsequently attached to each other to form the fixed scroll 130, 230. The first and second pieces 310, 320 may be fixed together by any appropriate method, e.g. by bolting. When attached, the two pieces define between them an internal cavity 340 fluidly connected to the inlet and outlet passages 330a, 330b. More specifically, when attached, the internal cavity 340 is defined by an internal surface of the first piece 310 and an internal surface of the second piece 320. When the first and second pieces 310, 320 are attached together, the inlet passages 330a, outlet passages 330b and the internal cavity 340 together form the cooling conduits 170, 270.

One or more surface structures for directing gas flow may be disposed on the internal surface of the first and/or second piece 310 to form galleries that act to direct gas flow from the inlet passages 330a to the outlet passages 330b. These surface structures also increase the amount of surface area for improved cooling of the gas passing over them. For example, the one or more surface features may comprise one or more of the following: one or more ridges, one or more grooves, one or more lattice structures, one or more fins, one or more folds.

Figures 4 and 5 are schematic illustrations (not to scale) showing perspective views of examples of the structures which may be formed on the internal surface of the first and/or second pieces 310, 320 described above with reference to Figure 3. Figure 4 shows a finned structure 410. The fins of the finned structure 410 may extend between the internal surfaces of the first piece 310 and the second piece 320. Figure 5 shows a honeycomb lattice structure 510.

Figures 6A to 6D are schematic illustrations (not to scale) showing perspective views of examples of inserts 600A, 600B, 600C, 600D which may be inserted into one or more of the cooling conduits 170, 270.

Each of the inserts 600A, 600B, 600C, 600D comprises an insert body 610A, 610B, 610C, 610C and an insert conduit 620A, 620B, 620C, 620D extending through the insert body 610A, 610B, 610C, 610C. The insert conduit 620A, 620B, 620C, 620D is defined by an internal surface of the insert body 610A, 610B, 610C, 610C. In the illustrated examples, the insert body 610A,

610B, 610C, 610C is elongate and the insert conduit 620A, 620B, 620C, 620D extends longitudinally through the elongate insert body 610A, 610B, 610C, 610C. When inserted, an insert 600A, 600B, 600C, 600D may be fixed in place by a friction fit between the insert body 610A, 610B, 610C, 610C and an internal surface of the fixed scroll 130, 230.

When an insert 600A, 600B, 600C, 600D is inserted in a cooling conduit 170, 270, cooling gas blown by the fan 160, 260 flows through the insert conduit 620A, 620B, 620C, 620D. In this way, the insert conduit 620A, 620B, 620C, 620D acts a cooling conduit for blown gas flowing through the fixed scroll 130, 230. The internal surface of the insert body 610A, 610B, 610C, 610C comprises one or more surface features for increasing surface area for cooling. For example, the one or more surface features may comprise one or more of the following: one or more ridges, one or more grooves, one or more lattice structures, one or more fins, one or more folds. It will be appreciated that the internal surface of an insert may, in general, be any form that will increase the surface area (relative to a smooth surface) for heat transfer.

Figure 6A shows an example of an insert 610A whose insert body's 610A internal surface has a plurality of helically extending ridges/grooves. Figure 6B shows an example of an insert 61 OB whose insert body's 61 OB internal surface has a plurality of ridges/grooves defining a star shape. Figure 6C shows an example of an insert 610C whose insert body's 610C internal surface has a plurality of folds. Figure 6D shows an example of an insert 610D whose insert body's 610D internal surface has a plurality of radially extending fins.

The use of an insert to provide said extra surface area tends to be advantageous because it tends to be easier to manufacture complex surface features in an insert rather than directly in the cooling conduit of the fixed scroll.

REFERENCE NUMERAL KEY Scroll pump: 100, 200 Casing: 110, 210 Orbiting scroll: 120, 220 Fixed scroll: 130, 230

Drive shaft: 140, 240 Motor: 150, 250 Fan: 160, 260 First base: 122, 222 First spiral wall: 124, 224

Second base: 132, 232 Second spiral wall 134, 234 Inlet: 172, 272 Outlet: 174, 274 Cowl: 280

First piece: 310 Second piece: 320 Inlet passage: 330a Outlet passage: 330b Internal cavity: 340

Finned structure: 410 Lattice structure: 510 Insert: 600A, 600B, 600C, 600D Insert body: 610A, 610B, 610C, 610D Insert conduit: 620A, 620B, 620C, 620D

Claims

1. A scroll pump comprising: a first scroll with a cooling conduit extending therethrough; and a fan configured to blow cooling gas towards the first scroll, wherein the cooling conduit is configured to receive cooling gas blown by the fan and convey the received cooling gas through the first scroll.

2. The scroll pump of claim 1 , further comprising a second scroll intermeshed with the first scroll, wherein the second scroll is located further away from the fan than the first scroll.

3. The scroll pump of claim 2, wherein one of the first and second scrolls is a fixed scroll and the other one of the first and second scrolls is an orbiting scroll.

4. The scroll pump of claim 3, further comprising a drive shaft coupled to the fan and at least one of the first and second scrolls, wherein the shaft is configured to rotate to drive the blowing of the fan and the orbiting of orbiting scroll.

5. The scroll pump of any one of claims 2 to 4, further comprising a cowl extending around the first and second scrolls, the cowl being configured to direct cooling gas exiting the cooling conduit around the first and second scrolls.

6. The scroll pump of claim 5, wherein the cowl is attached to the fixed scroll.

7. The scroll pump of claim 5 or 6, wherein the cowl comprises one or more surface features selected from the following group of surface features: one or more ridges, one or more grooves, one or more lattice structures, one or more fins, one or more folds.

8. The scroll pump of any one of the preceding claims, wherein the cooling conduit is defined by a surface and the surface comprises one or more surface features selected from the following group of surface features: one or more ridges, one or more grooves, one or more lattice structures, one or more fins, one or more folds.

9. The scroll pump of claim 6, wherein the surface defining the cooling conduit comprises a surface of an insert disposed within the first scroll.

10. The scroll pump of any one of the preceding claims, wherein the first scroll is formed from a single piece of material.

11. The scroll pump of any one of claims 1 to 9, wherein the first scroll is formed from two pieces of material attached to each other, wherein one of the two pieces comprises a spiral wall of the first scroll and the other one of the two pieces comprises an inlet passage of the cooling conduit and an outlet passage of the cooling conduit.

12. The scroll pump of any one of the preceding claims, wherein the cooling conduit extends from an axially facing surface of the first scroll to a circumferential surface of the first scroll.

13. The scroll pump of any one of the preceding claims, wherein the scroll pump comprises a plurality of cooling conduits, each of the plurality of cooling conduits being configured to receive cooling gas blown by the fan and convey the received cooling gas through the first scroll.

14. The scroll pump of claim 13, wherein each of the plurality of cooling conduits extends from an axially facing surface of the first scroll to a circumferential surface of the first scroll.

15. A vacuum pumping system comprising the scroll pump of any of claims 1