Vacuum pump cooler for cooling a pumped fluid in a multistage vacuum pump

Abstract

The present invention relates to a vacuum pump cooler (112, 114) for cooling one of the pumping fluids in a multi-stage vacuum pump (100), the vacuum pump cooler (112, 114) comprising: a plate (300, 320) comprising: a first surface (302, 322); a second surface (304, 324) opposite to the first surface (302, 322); a channel (308, 328) through which a cooling fluid can flow; and one or more fins (306, 326), or the like, extending from the second surface (304, 324) of the plate (300, 320).

Description

[Technical Field]

[0001] This invention relates to a vacuum pump cooler for cooling the pumped fluid in a multi-stage vacuum pump. [Previous Technology]

[0002] Vacuum pumps are used in various technical processes to pump gas out of the process chamber, thereby creating low-pressure conditions for the respective process.

[0003] In a multistage vacuum pump, gas is pumped through a continuous pumping stage. [Summary of the Invention]

[0004] When a fluid is pumped through the sequential stages of a multi-stage vacuum pump, the temperature of the pumped fluid often rises. This may be caused, for example, by the action (e.g., compression) of the fluid by the pumping mechanism of the pump.

[0005] Managing the thermal load within a multistage vacuum pump is often crucial for, for example, maintaining a good operating temperature, maintaining proper clearances within the pump, and ensuring that various components and working fluids operate as required. Poor thermal management can lead to a loss of pumping performance and reliability.

[0006] Conventionally, the external body of a vacuum pump is cooled in an attempt to remove the heat generated by the compression of the pumped fluid.

[0007] The inventors have recognized that more efficient cooling can be achieved by cooling the pumped fluid in the interstage region where the fluid travels from one stage to another. This cooling can be considered as "intermediate cooling".

[0008] The present invention provides a vacuum pump cooler and a vacuum pump, which provide intermediate cooling of the pumped fluid, thereby providing improved cooling effectiveness and thus improved pumping performance and reliability.

[0009] In one embodiment, a vacuum pump cooler is provided for cooling one of the pumping fluids in a multi-stage vacuum pump. The vacuum pump cooler includes a plate having a first surface, a second surface opposite to the first surface, and a channel through which cooling fluid can flow. The vacuum pump cooler further includes one or more fins extending from the second surface of the plate.

[0010] The vacuum pump cooler may include a plurality of fins.

[0011] The channel may be defined at least in part by one of the grooves formed in the first surface.

[0012] This passage can define a winding path.

[0013] At least a portion of the channel may be formed in one or more fins.

[0014] One or more of the fins may have a substantially U-shaped cross-section.

[0015] The plate may further include one or more ports, each configured to receive a respective purge valve.

[0016] The plate may further include an aperture extending between the first surface and the second surface, the aperture defining an inlet or outlet of the vacuum pump.

[0017] The vacuum pump cooler can be a single, integral item.

[0018] The vacuum pump cooler may be formed from a material selected from the group consisting of iron, ferroalloys, steel, anodized aluminum and aluminum alloys.

[0019] In a further embodiment, a multi-stage vacuum pump is provided, comprising: a first stage having a first pumping chamber having a first inlet and a first outlet; a second stage having a second pumping chamber having a second inlet and a second outlet; an interstage conduit fluidly coupling the first outlet and the second inlet; and a vacuum pump cooler according to any one of claims 1 to 10, wherein the vacuum pump cooler is configured such that one or more fins extend into the interstage conduit.

[0020] The multistage vacuum pump may further include a further vacuum pump cooler, which is a vacuum pump cooler according to any of the aforementioned configurations, wherein the further vacuum pump cooler is configured such that one or more fins of the further vacuum pump cooler extend into the interstage conduit.

[0021] The vacuum pump cooler and further vacuum pump coolers may define the opposing walls of a housing that accommodates the first stage, the second stage and the interstage conduit.

[0022] The vacuum pump cooler may include a first orifice extending between the first surface and the second surface of the vacuum pump cooler, the first orifice defining an inlet of the multistage vacuum pump. The further vacuum pump cooler may include a second orifice extending between the first surface and the second surface of the further vacuum pump cooler, the second orifice defining an outlet of the multistage vacuum pump.

Implementation Method

[0024] It should be understood that the relative terms such as above and below, horizontal and vertical, top and bottom, front and back are used only for the convenience of referring to the accompanying drawings, and such terms are not limited to these, and any two different directions or positions can be implemented, rather than actually above and below, horizontal and vertical, top and bottom, etc.

[0025] Figure 1 is a schematic cross-section of a side view of a multistage vacuum pump 100 (not to scale).

[0026] Figure 2 is a schematic cross-section of a front view of a multistage vacuum pump 100 (not to scale).

[0027] In this embodiment, the multistage vacuum pump 100 series is a Roots vacuum pump.

[0028] In this embodiment, the multi-stage vacuum pump 100 includes a housing 102. The housing 102 includes an upstream end wall 104, a downstream end wall 106 opposite to the upstream end wall 104, a first side wall 108, a second side wall 110 opposite to the first side wall 108, a first vacuum pump cooler 112, and a second vacuum pump cooler 114. The first vacuum pump cooler 112 forms a top wall or upper wall of the housing 102. The second vacuum pump cooler 114 forms a bottom wall or lower wall of the housing 102. The second vacuum pump cooler 114 is positioned opposite to the first vacuum pump cooler 112.

[0029] The functionality of the first vacuum pump cooler 112 and the second vacuum pump cooler 114, etc., will be described in more detail below with reference to Figures 3 and 4.

[0030] The housing 102 defines a plurality of pumping stages, namely a first pumping stage 121, a second pumping stage 122, a third pumping stage 123, a fourth pumping stage 124, a fifth pumping stage 125, and a sixth pumping stage 126. The pumping stages 121 to 126 of the multi-stage vacuum pump 100 are defined by partition walls 128 within the housing 102. For example, partition walls 128 may be integral with one or more of the upstream end wall 104, the downstream end wall 106, the first side wall 108, and the second side wall 110.

[0031] For each pumping stage 121 to 126, the housing 102 defines a respective stator including one of the stator holes. Thus, the housing defines a first stator hole 131, a second stator hole 132, a third stator hole 133, a fourth stator hole 134, a fifth stator hole 135 and a sixth stator hole 136.

[0032] The multistage vacuum pump 100 includes a rotor assembly comprising two shaft members, namely a first shaft member 141 and a second shaft member 142. The two shaft members 141 and 142 are configured to rotate in opposite directions about parallel rotation axes. The first shaft member 141 is configured to rotate about a first rotation axis 143. The second shaft member 142 is configured to rotate about a second rotation axis 144.

[0033] Each shaft member 141, 142 includes a plurality of rotors. Each rotor of each shaft member 141, 142 is positioned within one of the stator bores 131 to 136. Thus, each stator bore 131 to 136 has a pair of rotors positioned therein, each rotor of the pair of rotors being mounted to one of the two shaft members 141, 142.

[0034] Figure 1 shows a plurality of first rotors 146, each first rotor 146 being positioned in a respective stator bore 131, 136. Figure 2 shows a pair of rotors positioned in the first stator bore 131, namely a first rotor 146 and a second rotor 148.

[0035] Rotors 146 and 148 are each a three-lobed rotor.

[0036] For each stator bore 131 to 136, the pair of rotors 146, 148 positioned therein are cooperating rotors configured to rotate within the stator bores 131 to 136. For each stator bore 131 to 136, the rotors 146, 148 mounted therein have a cooperating dimension with the stator bores 131 to 136 such that when rotating within the stator bores 131 to 136, the outer edge of each rotor 146, 148 away from the other rotor 146, 148 seals against the stator bores 131 to 136.

[0037] Each of the stator holes 131 to 136 includes a respective inlet and a respective outlet. Specifically, in this embodiment, the first stator hole 131 includes a first inlet 151 and a first outlet 161, the second stator hole 132 includes a second inlet 152 and a second outlet 162, the third stator hole 133 includes a third inlet 153 and a third outlet 163, the fourth stator hole 134 includes a fourth inlet 154 and a fourth outlet 164, the fifth stator hole 135 includes a fifth inlet 155 and a fifth outlet 165, and the sixth stator hole 136 includes a sixth inlet 156 and a sixth outlet 166.

[0038] The multistage vacuum pump 100 includes a plurality of interstage conduits that fluidly connect pumping stages 121 to 126 together and allow fluid flow through the continuous pumping stages 121 to 126. In this embodiment, the interstage conduits travel around an outer surface of one of the stators. A first interstage conduit (indicated by element 171 in FIG. 2) fluidly connects a first outlet 161 to a second inlet 152. Furthermore, a second interstage conduit fluidly connects a second outlet 162 to a third inlet 153. Furthermore, a third interstage conduit fluidly connects a third outlet 163 to a fourth inlet 154. Furthermore, a fourth interstage conduit fluidly connects a fourth outlet 164 to a fifth inlet 155. Furthermore, a fifth interstage conduit fluidly connects a fifth outlet 165 to a sixth inlet 156.

[0039] The multistage vacuum pump 100 includes a pump inlet 170 and a pump outlet 172. The pump inlet 170 is connected to a first inlet 151 of a first stator bore 131. The pump outlet 172 is connected to a sixth outlet 166 of a sixth stator bore 136.

[0040] In operation, (e.g., by means of an electric motor) rotating shafts 141, 142 cause rotors 146, 148 to rotate within stator bores 131 to 136. The rotation of rotors 146, 148 within the first stator bore 131 draws gas into the first stator bore 131 via pump inlet 170 and first inlet 151. This gas flow into the multistage vacuum pump 100 is illustrated in Figures 1 and 2 by dashed arrows and component symbol 180. The continuous rotation of rotors 146, 148 within stator bores 131 to 136 causes gas to move through continuous pumping stages 121 to 126 via interstage conduits. Specifically, in this embodiment, the pumping gas is pumped through the multi-stage vacuum pump 100 as follows: the gas is pumped out of the first stator bore 131 via the first outlet 161, and through the first interstage conduit 171 to the second inlet 152, through which the gas enters the second stator bore 132 (this gas flow is indicated in Figures 1 and 2 by a dashed arrow and component symbol 182); then, the gas is pumped out of the second stator bore 132 via the second outlet 162, and through a second interstage conduit to the third inlet 153, through which the gas enters the third stator bore 133; then, the gas is pumped out of the third stator bore 133 via the third outlet 163, and through a third interstage conduit to the fourth inlet 154, through which the gas enters the fourth stator bore 134; then, the gas... Gas is pumped out of the fourth stator bore 134 from the fourth outlet 164 and passes through a fourth interstage conduit to the fifth inlet 155, through which it enters the fifth stator bore 135. Next, the gas is pumped out of the fifth stator bore 135 from the fifth outlet 165 and passes through a fifth interstage conduit to the sixth inlet 156, through which it enters the sixth stator bore 136. Then, the gas is pumped out of the sixth stator bore 136 from the sixth outlet 166 and pumped out of the pump 100 from the pump outlet 172. This gas flow leaving the multistage vacuum pump 100 is shown in Figure 1 by a dashed arrow and component symbol 184.

[0041] Figure 3 is a schematic illustration of an exploded perspective view of the housing 102 (not to scale).

[0042] Figure 4 is a schematic illustration of one of the further exploded perspective views of the housing 102 (not to scale).

[0043] In this embodiment, a first vacuum pump cooler 112 forms a top wall of the housing 102. The first vacuum pump cooler 112 is attached to a top surface of an assembly including an upstream end wall 104, a downstream end wall 106, a first side wall 108, and a second side wall 110. The first vacuum pump cooler 112 may be attached to the assembly by any suitable means, such as by using a plurality of fasteners.

[0044] The first vacuum pump cooler 112 includes a first plate 300 having a first surface 302 and a second surface 304 opposite to the first surface 302.

[0045] In this embodiment, the first surface 302 is a top surface of the first plate 300, and the second surface 304 is a bottom surface of the first plate 300. When the first vacuum pump cooler 112 is attached to the top surface of the assembly, the first surface 302 forms an outer surface of the housing 102. Furthermore, the second surface 304 of the first plate 300 contacts the top edges of the upstream end wall 104, the downstream end wall 106, the first side wall 108, and the second side wall 110. The second surface 304 of the first plate 300 can be sealed against the top edges of the upstream end wall 104, the downstream end wall 106, the first side wall 108, and the second side wall 110, for example, by means of an O-ring or gasket disposed therebetween.

[0046] The first vacuum pump cooler 112 further includes a plurality of first fins 306 extending downward from the second surface 304 of the first plate 300. In this embodiment, there are eight first fins 306. Preferably, the first fins 306 are integrally formed with the first plate 300. This often reduces or eliminates air gaps or joints between the first fins 306 and the first plate 300 to provide improved thermal conductivity and improved heat transfer between them.

[0047] When the first vacuum pump cooler 112 is attached to the top surface of the assembly to form the upper wall of the housing 102, the first fin 306 extends into the interstage conduit. One or more first fins 306 may extend into each of the interstage conduits. More preferably, a plurality of first fins 306 extend into each of the interstage conduits. As shown in FIG2, at least one first fin 306 extends downward from the second surface 304 of the first plate 300 into the first interstage conduit 171.

[0048] In this embodiment, when viewed from the front, the first fin 306 appears as a substantially U-shaped fin, which can be considered as having a substantially U-shaped cross-section. This allows the first fin 306 to extend through the interstage guides surrounding both sides of the stator. In some embodiments, when viewed from below, the first fin 306 may appear as a substantially U-shaped fin, which can be considered as having a substantially U-shaped cross-section. This allows the first fin 306 to extend along the interstage guides. The shape of the first fin 306 may be application-dependent and may depend on the size and shape of the interstage guides through which the first fin 306 extends when the housing 102 is assembled.

[0049] The first plate 300 includes a first channel 308. The first channel 308 is a channel through which a cooling fluid can flow. In this embodiment, the first channel 308 is defined by a groove formed in a first surface 302 of the first plate 300. In this embodiment, the first channel 308 defines a meandering or spiral path above the first surface 302 of the first plate 300. In some embodiments, the first channel may include one or more gaps or cavities.

[0050] In this embodiment, the first plate 300 includes a plurality of ports 310. Each port 310 extends from the first surface 302 through a hole in the first plate 300 to the second surface 304. Each port 310 is configured to receive a respective purge valve.

[0051] In this embodiment, a plurality of purge valves are provided in the assembled multistage vacuum pump 100. Each purge valve is disposed in one of the plurality of ports 310. One or more purge valves constitute a pressure relief system configured to release pressure in the stator ports 131 to 136 of the multistage vacuum pump 100. One or more purge valves are configured to be in a closed position when the pressure in one or more of the stator ports 131 to 136 is below a threshold pressure, thereby preventing or obstructing airflow through them. Furthermore, one or more purge valves are configured to be open when the pressure in one or more of the stator ports 131 to 136 is greater than or equal to the threshold pressure, thereby allowing gas to flow out of one or more of the stator ports 131 to 136 to the external atmosphere. In this way, pressure within the multistage vacuum pump 100 can be released. This advantageously reduces the load on rotors 146 and 148 and prevents excessive compression of the pumped gas.

[0052] In this embodiment, the first plate 300 further includes a first aperture 312. The first aperture 312 extends from the first surface 302 through the first plate 300 to the second surface 304. The first aperture 312 fluidly connects the pump inlet 170 to the first inlet 151. Therefore, the first aperture 312 can be considered as at least partially defining one of the inlets of the multi-stage vacuum pump 100. In operation, gas is pumped into the pump inlet 170, through the first aperture 312, and then through the first inlet 151 to the first stator aperture 131.

[0053] In this embodiment, the first vacuum pump cooler 112 is a single, integral article. The first vacuum pump cooler 112 may be a monolithic component or product. As used herein, the term "monolithic" may mean comprising a substantially single unit, which in some embodiments may be a single piece formed, composed, or produced without joints or seams, and comprising a substantially homogeneous but not necessarily rigid whole. The first vacuum pump cooler 112 may be undifferentiated, i.e., formed from a single material, which may be substantially homogeneous within the component.

[0054] The first vacuum pump cooler 112 is formed of a thermally conductive material, such as one of the materials group selected from iron, iron alloys, steel, anodized aluminum and aluminum alloys.

[0055] The first vacuum pump cooler 112 may be manufactured by any suitable manufacturing technique, including but not limited to machining from a solid workpiece or blank, casting or manufacturing by lamination.

[0056] In this embodiment, the second vacuum pump cooler 114 forms a bottom wall of the housing 102, which is opposite to the top wall formed by the first vacuum pump cooler 112. The second vacuum pump cooler 114 is attached to a bottom surface of an assembly including an upstream end wall 104, a downstream end wall 106, a second side wall 108, and a second side wall 110. The second vacuum pump cooler 114 can be attached to the assembly by any suitable means, such as by using a plurality of fasteners.

[0057] The second vacuum pump cooler 114 includes a second plate 320 having a first surface 322 and a second surface 324 opposite to the first surface 322.

[0058] In this embodiment, the first surface 322 is a bottom surface of the second plate 300, and the second surface 324 is a top surface of the second plate 320. When the second vacuum pump cooler 114 is attached to the bottom surface of the assembly, the first surface 322 forms an outer surface of the housing 102. Furthermore, the second surface 324 of the second plate 320 contacts the bottom edges of the upstream end wall 104, downstream end wall 106, first side wall 108, and second side wall 110. The second surface 324 of the second plate 320 can be sealed against the bottom edges of the upstream end wall 104, downstream end wall 106, first side wall 108, and second side wall 110, for example, by means of an O-ring or gasket disposed therebetween.

[0059] The second vacuum pump cooler 114 further includes a plurality of second fins 326 extending upward from the second surface 304 of the second plate 300. In this embodiment, there are 13 second fins 306. Preferably, the second fins 326 are integrally formed with the second plate 320. This often reduces or eliminates air gaps or joints between the second fins 326 and the second plate 320 to provide improved thermal conductivity and improved heat transfer between them.

[0060] When the second vacuum pump cooler 114 is attached to the bottom surface of the assembly to form the lower wall of the housing 102, the second fin 326 extends into the interstage conduit. One or more second fins 326 may extend into each of the interstage conduits. More preferably, a plurality of second fins 326 extend into each of the interstage conduits. As shown in FIG2, at least one second fin 326 extends upward from the second surface 324 of the second plate 320 into the second interstage conduit 171.

[0061] In this embodiment, when viewed from the front, the second fin 326 appears as a substantially U-shaped fin, which can be considered as having a substantially U-shaped cross-section. This allows the second fin 326 to extend through the interstage guides surrounding both sides of the stator. In some embodiments, when viewed from above, the second fin 326 may appear as a substantially U-shaped fin, which can be considered as having a substantially U-shaped cross-section. This allows the second fin 326 to extend along the interstage guides. The shape of the second fin 326 may be application-dependent and may depend on the size and shape of the interstage guides through which the second fin 326 extends when the housing 102 is assembled.

[0062] The second plate 320 includes a second channel 328. The second channel 328 is a channel through which cooling fluid can flow. In this embodiment, the second channel 328 is defined by a groove formed in the first surface 322 of the second plate 320. In this embodiment, the second channel 328 defines a meandering or spiral path above the first surface 322 of the second plate 320.

[0063] In this embodiment, the second plate 320 further includes a second aperture 332. The second aperture 332 extends from the first surface 322 through the second plate 320 to the second surface 324. The second aperture 332 fluidly connects the pump outlet 172 to the sixth outlet 166. Therefore, the second aperture 332 can be considered as at least partially defining one of the outlets of the multistage vacuum pump 100. In operation, gas is pumped out of the sixth stator hole 136 through the sixth outlet 166, through the second aperture 332, and then through the pump outlet 172.

[0064] In this embodiment, the second vacuum pump cooler 114 is a single, integral article. The second vacuum pump cooler 114 may be a single component or product.

[0065] The second vacuum pump cooler 114 is formed of a thermally conductive material, such as one of the materials group selected from iron, iron alloys, steel, anodized aluminum and aluminum alloys.

[0066] The second vacuum pump cooler 114 can be manufactured by any suitable manufacturing technique, including but not limited to machining from a solid workpiece or blank, casting or manufacturing by lamination.

[0067] In operation, gas is pumped through successive stages 121 to 126 of the multi-stage vacuum pump 100, as described in more detail above. The pumped gas travels between successive stages 121 to 126 of the pump 100 via interstage conduits (such as the first conduit 171). As the pumped gas travels through the interstage conduits, it travels above (i.e., in contact with) the first fins 306 and the second fins 326 located within the interstage conduits. As the pumped gas travels above the first and second fins 306, 326, heat from the gas is transferred to the fins 306, 326. Thus, the pumped gas is cooled. Since the first and second fins 306, 326 are integral with (or at least attached to) the first and second plates 300, 320, respectively, the heat transferred to the fins 306, 326 is transferred to the plates 300, 320. Furthermore, during operation, a cooling fluid (i.e., a gaseous or liquid coolant, such as water or water containing an anti-corrosion additive) flows along the first and second channels 308 and 328 formed in the first and second plates 300 and 320, respectively. This cooling fluid flows through the channels 308 and 328 to cool the plates. Therefore, the heat transferred from the pumping gas to the plates 300 and 320 by the fins 306 and 326 is removed from the plates.

[0068] In this embodiment, it is advantageous to apply the cooling fluid directly to the vacuum pump coolers 112, 114. This often provides more efficient heat transfer from the vacuum pump coolers 112, 114, and thus more efficient cooling of the pumped gas.

[0069] Cooling fluid can flow from one of the cooling fluid sources outside the multistage vacuum pump 100 to the first and second channels 308 and 328 formed in the first and second plates 300 and 320. Cooling fluid can flow out of the first and second channels 308 and 328 formed in the first and second plates 300 and 320 to a cooling fluid discharge tank outside the multistage vacuum pump 100.

[0070] The vacuum pump cooler described above provides "intermediate cooling" for a pumped gas, that is, cooling a pumped gas in the interstage region of a multi-stage vacuum pump.

[0071] Compared to other vacuum pumps (such as reverse claw or screw pumps), the gas paths between the sequential stages of a multistage Roots vacuum pump tend to be relatively long. The vacuum pump cooler described above utilizes these relatively long interstage gas paths or ducts to provide effective interstage cooling.

[0072] Advantageously, the improved cooling often provided by the vacuum pump cooler described above often helps to maintain a good operating temperature of the pump and maintain the correct clearance within the pump, and often ensures that various components and working fluids operate as needed.

[0073] Improved cooling, often provided by the vacuum pump cooler described above, often provides improved pumping performance and reliability.

[0074] Advantageously, the vacuum pump cooler is a single-piece, monolithic entity formed of a thermally conductive material. Therefore, smaller components, such as cooling tubes, are often avoided, as they may suffer fatigue failure when made of highly conductive materials such as aluminum or copper.

[0075] Advantageously, the vacuum cooler described above avoids the use of conduits of a first material that are at least partially embedded in a support structure (such as a casting) of a second material. Therefore, the possibility of thermal cavitation between the two different materials is often eliminated. The cooler described above can be formed substantially from a single material having a predetermined or desired thermal conductivity. Therefore, the vacuum pump cooler described above often provides improved thermal conductivity and thus provides more efficient cooling of the pumped fluid.

[0076] Advantageously, the vacuum cooler described above is often robust against fatigue and cracking, for example, fatigue and cracking caused by corrosive and / or high-temperature gases pumped by a vacuum pump.

[0077] The vacuum pump cooler described above can be easily removed from the housing, for example for cleaning or inspection.

[0078] In the above embodiments, the multistage vacuum pump is a Roots vacuum pump. However, in other embodiments, the multistage vacuum pump is a different type of multistage vacuum pump, such as a multistage claw pump.

[0079] In the above embodiments, the multi-stage vacuum pump includes two vacuum pump coolers. However, in other embodiments, the pump includes a different number of vacuum pump coolers, such as only one single cooler or more than two coolers. For example, in some embodiments, one of the first or second vacuum coolers is omitted and can be replaced by a standard or conventional housing wall.

[0080] In the above embodiments, the first vacuum pump cooler forms one of the top walls or upper walls of the housing. However, in other embodiments, the first vacuum cooler forms a different wall of the housing, such as one of the side walls of the housing.

[0081] In the above embodiments, the second vacuum pump cooler forms one of the bottom or lower walls of the housing. However, in other embodiments, the second vacuum cooler forms a different wall of the housing, such as one of the side walls of the housing.

[0082] In the above embodiments, the multi-stage vacuum pump includes six stages. However, in other embodiments, the multi-stage vacuum pump includes a different number of stages, i.e., fewer than six or more than six.

[0083] In the above embodiments, each pumping stage includes a respective pair of cooperating rotors. However, in other embodiments, one or more pumping stages may include a different type of pumping mechanism, such as a pumping mechanism with a different number of rotors.

[0084] In the above embodiment, the rotor is a three-lobed rotor. However, in other embodiments, one or more of the rotors have a different number of lobes, such as two lobes or more than three lobes.

[0085] In the above embodiments, the first vacuum pump cooler includes eight first fins. However, in other embodiments, the first vacuum pump cooler includes a different number of first fins, for example, fewer than eight or more than eight. The number of fins in the first vacuum pump cooler may be application-dependent and may depend on factors including, but not limited to, the number of pumping stages and the size of the interstage conduits.

[0086] In the above embodiments, the second vacuum pump cooler includes thirteen second fins. However, in other embodiments, the second vacuum pump cooler includes a different number of first fins, for example, fewer than thirteen or more than thirteen. The number of fins in the second vacuum pump cooler may be application-dependent. The number of fins in the second vacuum pump cooler may depend on factors including, but not limited to, the number of pumping stages and the size of the interstage conduits.

[0087] In the above embodiments, the first fin may be a substantially U-shaped fin, that is, it may be considered to have a substantially U-shaped cross-section. However, in other embodiments, one or more of the first fins may have a different shape other than U-shaped.

[0088] In the above embodiments, the second fin may be a substantially U-shaped fin, that is, it may be considered to have a substantially U-shaped cross-section. However, in other embodiments, one or more of the second fins may have a different shape than U-shaped.

[0089] In the above embodiments, the first plate includes a plurality of ports therein for receiving a purge valve. However, in other embodiments, the first plate includes a different number of ports and purge valves than shown in the figures. In some embodiments, the ports and purge valves are omitted. In some embodiments, some or all of the ports and purge valves are located on a different wall of the housing other than the first vacuum cooler, i.e., the top wall. For example, in other embodiments, one or more of the upstream end wall, downstream end wall, first side wall, second side wall, and bottom wall (i.e., the second vacuum cooler) may include ports therein for receiving one or more of their respective purge valves.

[0090] In the above embodiments, the first and second plates each include a respective channel through which a cooling fluid flows. However, in other embodiments, one or both of the first and second plates include a different number of such channels, i.e., multiple channels. The one or more channels may have any suitable shape.

[0091] Therefore, one or both of the vacuum pump coolers may have a shape or configuration different from that described above. Figure 5 is a schematic illustration of one of the first and second vacuum pump coolers 112, 114 according to a further embodiment. In the embodiment shown in Figure 5, the number and shape of the fins 306, 326, the shape and configuration of the first channel 308, and the number and configuration of the ports 310 are different from those shown in Figures 3 and 4 and described above.

[0092] In the above embodiments, the cooling fluid channel is formed by grooves in the first surfaces of the first and second plates. However, in other embodiments, at least a portion of one or both channels is not formed by a groove in a surface of a vacuum pump cooler. For example, in some embodiments, one or more channels are formed through a conduit, tube, or hole through a plate of a vacuum pump cooler. In some embodiments, at least a portion of a channel of a vacuum pump cooler extends into a conduit, tube, or hole in the body of one or more fins. In other words, at least a portion of a channel may be formed in one or more fins. Thus, cooling fluid can flow through one or more fins. This often provides improved cooling of the fins, and therefore improved cooling of the pumped gas. [Simplified Explanation of the Diagram]

[0023] Figure 1 is a schematic drawing of a side view cross section of a vacuum pump (not to scale); Figure 2 is a schematic drawing of a front view cross section of a vacuum pump (not to scale); Figure 3 is a schematic drawing of an exploded perspective view of a vacuum pump housing (not to scale); Figure 4 is a schematic drawing of a further exploded perspective view of a vacuum pump housing (not to scale); and Figure 5 is a schematic drawing of a perspective view of a vacuum pump cooler (not to scale).

Claims

1. A vacuum pump cooler for cooling one of the pumped fluids in a multi-stage vacuum pump, the vacuum pump cooler comprising: A plate includes: a first surface; a second surface opposite to the first surface; a channel through which a cooling fluid can flow; and one or more fins, or the like, extending from the second surface of the plate, wherein at least a portion of the channel is formed in the one or more fins.

2. The vacuum pump cooler of claim 1, wherein the number of the one or more fins is multiple.

3. The vacuum pump cooler of claim 1 or 2, wherein the channel is at least partially defined by one of the grooves formed in the first surface.

4. A vacuum pump cooler as requested in item 1 or 2, wherein the channel defines a meandering path.

5. A vacuum pump cooler as claimed in claim 1 or 2, wherein one or more of the one or more fins have a substantially U-shaped cross-section.

6. The vacuum pump cooler of claim 1 or 2, wherein the plate further includes one or more ports, each configured to receive a respective purge valve.

7. The vacuum pump cooler of claim 1 or 2, wherein the plate further includes an aperture extending between the first surface and the second surface, the aperture defining an inlet or outlet of the vacuum pump.

8. The vacuum pump cooler as requested in item 1 or 2, wherein the vacuum pump cooler is a single integral article.

9. The vacuum pump cooler of claim 1 or 2, wherein the vacuum pump cooler is formed of a material selected from the group consisting of iron, ferroalloys, steel, anodized aluminum and aluminum alloys.

10. A multi-stage vacuum pump, comprising: A first stage, having a first pumping chamber having a first inlet and a first outlet; A second stage having a second pumping chamber having a second inlet and a second outlet; an interstage conduit fluidly coupling the first outlet and the second inlet; and a vacuum pump cooler as claimed in any one of claims 1 to 9, wherein the vacuum pump cooler is configured such that the one or more fins extend into the interstage conduit.

11. The multistage vacuum pump of claim 10, further comprising a further vacuum pump cooler, the further vacuum pump cooler being any one of claims 1 to 9, wherein the further vacuum pump cooler is configured such that one or more fins of the further vacuum pump cooler extend into the interstage conduit.

12. The multistage vacuum pump of claim 11, wherein the vacuum pump cooler and the further vacuum pump cooler define opposing walls of a housing accommodating the first stage, the second stage and the interstage conduit.

13. A multistage vacuum pump as requested in item 11 or 12, wherein: The vacuum pump cooler includes a first aperture extending between the first surface and the second surface of the vacuum pump cooler, the first aperture defining an inlet of the multistage vacuum pump; and the further vacuum pump cooler includes a second aperture extending between the first surface and the second surface of the further vacuum pump cooler, the second aperture defining an outlet of the multistage vacuum pump.

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