GB2590666A - Multi-stage vacuum pump - Google Patents

Multi-stage vacuum pump Download PDF

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Publication number
GB2590666A
GB2590666A GB1919167.5A GB201919167A GB2590666A GB 2590666 A GB2590666 A GB 2590666A GB 201919167 A GB201919167 A GB 201919167A GB 2590666 A GB2590666 A GB 2590666A
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GB
United Kingdom
Prior art keywords
vacuum
stage
vacuum stage
stages
over
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
GB1919167.5A
Other versions
GB201919167D0 (en
Inventor
Zahradka Martin
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Edwards sro
Original Assignee
Edwards sro
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Edwards sro filed Critical Edwards sro
Priority to GB1919167.5A priority Critical patent/GB2590666A/en
Publication of GB201919167D0 publication Critical patent/GB201919167D0/en
Priority to PCT/EP2020/087056 priority patent/WO2021130117A1/en
Publication of GB2590666A publication Critical patent/GB2590666A/en
Pending legal-status Critical Current

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C23/00—Combinations of two or more pumps, each being of rotary-piston or oscillating-piston type, specially adapted for elastic fluids; Pumping installations specially adapted for elastic fluids; Multi-stage pumps specially adapted for elastic fluids
    • F04C23/001—Combinations of two or more pumps, each being of rotary-piston or oscillating-piston type, specially adapted for elastic fluids; Pumping installations specially adapted for elastic fluids; Multi-stage pumps specially adapted for elastic fluids of similar working principle
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C25/00—Adaptations of pumps for special use of pumps for elastic fluids
    • F04C25/02—Adaptations of pumps for special use of pumps for elastic fluids for producing high vacuum
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C28/00—Control of, monitoring of, or safety arrangements for, pumps or pumping installations specially adapted for elastic fluids
    • F04C28/02—Control of, monitoring of, or safety arrangements for, pumps or pumping installations specially adapted for elastic fluids specially adapted for several pumps connected in series or in parallel
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C28/00—Control of, monitoring of, or safety arrangements for, pumps or pumping installations specially adapted for elastic fluids
    • F04C28/24—Control of, monitoring of, or safety arrangements for, pumps or pumping installations specially adapted for elastic fluids characterised by using valves controlling pressure or flow rate, e.g. discharge valves or unloading valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C28/00—Control of, monitoring of, or safety arrangements for, pumps or pumping installations specially adapted for elastic fluids
    • F04C28/28—Safety arrangements; Monitoring
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C29/00—Component parts, details or accessories of pumps or pumping installations, not provided for in groups F04C18/00 - F04C28/00
    • F04C29/0021—Systems for the equilibration of forces acting on the pump
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C2270/00—Control; Monitoring or safety arrangements
    • F04C2270/17—Tolerance; Play; Gap

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Applications Or Details Of Rotary Compressors (AREA)

Abstract

A multi-stage vacuum pump, comprising at least one higher vacuum stage 30, 40, 50, at least one lower vacuum stage 60, 70, 80, 85, and an over-pressure device 120 operable to selectively couple said lower vacuum stage with said higher vacuum stage. This over-pressure device serves as a relief valve, to allow for reduction of pressure in the low vacuum stages thereby preventing improper pump operation. The over-pressure device may comprise a valve biased closed by a biasing force, the valve actuated by a pressure differential between said higher and lower vacuum stages. The stages may comprise a common rotor urged into position by an urging force, where his urging force exceeds said biasing force. The over pressure device may draw working fluid from a lower vacuum stage with the lowest vacuum, or one other than the highest vacuum lower vacuum stage. The over-pressure device may deliver working fluid to a highest vacuum stage of the lower vacuum stages, or to a stage other than the highest vacuum of the lower vacuum stages.

Description

MULTI-STAGE VACUUM PUMP
FIELD OF THE INVENTION
The present invention relates to a multi-stage vacuum pump.
BACKGROUND
Vacuum pumps are known. These pumps are typically employed as a component of a vacuum system to evacuate devices. Also, these pumps are used to evacuate fabrication equipment used in, for example, the production of io semiconductors. Rather than performing compression from a vacuum to atmosphere in a single stage using a single pump, it is known to provide multistage vacuum pumps where each stage performs a portion of the complete compression range required to transition from a vacuum to atmospheric pressure. Multi-stage vacuum pumps help to reduce pump leakage and reduce power consumption compared to a single-stage vacuum pump.
Although such multi-stage vacuum pumps provide advantages, they also have their own shortcomings. Accordingly, it is desired to provide an improved arrangement for multi-stage vacuum pumps.
SUMMARY
According to a first aspect, there is provided a multistage vacuum pump having a plurality of stages, comprising: at least one higher vacuum stage which is operable to receive fluid from a high vacuum device to be compressed; at least one lower vacuum stage which is operable to receive compressed fluid from the at least one higher vacuum stage; and an over-pressure device operable to selectively couple the at least one lower vacuum stage with the at least one higher vacuum stage.
The first aspect recognizes that a problem with existing multistage pumps is that a blockage in one of the stages can cause a pressure build-up in the outlet of that stage which can cause incorrect operation of the pump such as, for example, -2 -typically axial displacement of the rotor which may lead to clashes between the rotor and the stator. Accordingly, a pump is provided. The pump may be a multistage vacuum pump. The pump may have a plurality of different stages. The pump may comprise a higher vacuum stage which receives fluid to be compressed from a device. The pump may comprise a lower vacuum stage. The lower vacuum stage may be configured to experience a lower vacuum than the higher vacuum stage. The lower vacuum stage may receive the compressed fluid from the higher vacuum stage. The pump may comprise an over-pressure device or mechanism. The over-pressure device may selectively, actuateably or configurably couple the lower vacuum stage with the higher vacuum stage. In this way, when required, the over-pressure device may be actuated to couple the lower vacuum stage with the higher vacuum stage in order to prevent damage caused by incorrect operation of the multistage pump due to, for example, a blockage.
The over-pressure device may be operable to selectively couple the at least one lower vacuum stage with the at least one higher vacuum stage to convey at least some of the compressed fluid from the at least one lower vacuum stage to the at least one higher vacuum stage in response to a blockage.
The over-pressure device may be operable to selectively couple the at least one lower vacuum stage with the at least one higher vacuum stage to convey at least some of the compressed fluid from the at least one lower vacuum stage to the at least one higher vacuum stage. Accordingly, when the over-pressure device is actuated then this allows fluid to be transferred from the lower vacuum stage to the higher vacuum stage to help prevent incorrect operation of the multistage pump.
The over-pressure device may be operable to selectively couple the at least one 30 lower vacuum stage with the at least one higher vacuum stage when a pressure differential across the over-pressure device exceeds a threshold amount. Accordingly, when a predetermined or selected amount of pressure is generated -3 -in the lower vacuum stage then the over-pressure device may be actuated to convey fluid out of the lower pressure stage in order to reduce pressure and prevent incorrect operation of the pump occurring.
The over-pressure device may comprise a valve biased closed by a biasing force and the plurality of stages may comprise a common rotor urged into position by an urging force, wherein the urging force exceeds the biasing force. Accordingly, the pressure required to activate the over-pressure device may be smaller than the pressure that would cause the rotor to displace and clash against the stator.
io Accordingly, the over-pressure device may actuate before any clashing occurs.
The pump may comprise a plurality of lower vacuum stages, each being a sequentially decreasing lower vacuum stage and the over-pressure device may be operable to couple other than a highest vacuum stage of the lower vacuum stages with the at least one higher vacuum stage. Accordingly, a number of lower vacuum stages ma1y be provided. The lower vacuum stages may each experience a lower vacuum than any of the higher vacuum stages. The lower vacuum stages may be arranged in series with the output of a preceding stage feeding the input of a subsequent stage. Each stage increases the compression of the fluid compared to the preceding stage. Accordingly, each stage supports a lower vacuum than the preceding stage. The over-pressure device may be coupled to a stage in the lower vacuum stages which is not the stage having the highest vacuum.
The pump may comprise comprising a plurality of lower vacuum stages, each being a sequentially decreasing lower vacuum stage and wherein the overpressure device is operable to couple a lowest vacuum stage of the lower vacuum stages with the at least one higher vacuum stage. For example, the over-pressure device may be coupled to the pump exhaust.
The pump may comprise a plurality of higher vacuum stages, each being a sequentially decreasing higher vacuum stage and wherein the over-pressure -4 -device is operable to couple the at least one lower vacuum stage with other than a lowest vacuum stage of the higher vacuum stages. Accordingly, a number of higher vacuum stages may be provided. The higher vacuum stages may each experience a higher vacuum than any of the lower vacuum stages. The higher vacuum stages may be arranged in series with the output of a preceding stage feeding the input of a subsequent stage. Each stage increases the compression of the fluid compared to the preceding stage. Accordingly, each stage supports a lower vacuum than the preceding stage. The over-pressure device may be coupled to a stage in the higher vacuum stages which is not the stage having the io lowest vacuum.
The pump may comprise a plurality of higher vacuum stages, each being a sequentially decreasing higher vacuum stage and wherein the over-pressure device is operable to couple the at least one lower vacuum stage with a highest vacuum stage of the lower vacuum stages. For example, the over-pressure device may be coupled to the pump inlet.
According to a second aspect, there is provided a method, comprising: providing a multistage vacuum pump having a plurality of stages, comprising at least one higher vacuum stage which is operable to receive fluid from a high vacuum device to be compressed, and at least one lower vacuum stage which is operable to receive compressed fluid from the at least one higher vacuum stage; and selectively coupling the at least one lower vacuum stage with the at least one higher vacuum stage.
The selectively coupling may comprise selectively coupling the at least one lower vacuum stage with the at least one higher vacuum stage to convey at least some of the compressed fluid from the at least one lower vacuum stage to the at least one higher vacuum stage. -5 -
The selectively coupling may comprise selectively coupling the at least one lower vacuum stage with the at least one higher vacuum stage when a pressure differential across the over-pressure device exceeds a threshold amount.
The selectively coupling may comprise coupling with an over-pressure device comprising a valve biased closed by a biasing force, the plurality of stages comprise a common rotor urged into position by an urging force and wherein the urging force exceeds the biasing force.
The pump may comprise a plurality of lower vacuum stages, each being a sequentially decreasing lower vacuum stage and the coupling may comprise coupling other than a highest vacuum stage of the lower vacuum stages with the at least one higher vacuum stage.
The pump may comprise a plurality of lower vacuum stages, each being a sequentially decreasing lower vacuum stage and the coupling may comprise coupling a lowest vacuum stage of the lower vacuum stages with the at least one higher vacuum stage.
The pump may comprise a plurality of higher vacuum stages, each being a sequentially decreasing higher vacuum stage and the coupling may comprise coupling the at least one lower vacuum stage with other than a lowest vacuum stage of the higher vacuum stages.
The pump may comprise a plurality of higher vacuum stages, each being a sequentially decreasing higher vacuum stage and the coupling may comprise coupling the at least one lower vacuum stage with a highest vacuum stage of the lower vacuum stages.
Further particular and preferred aspects are set out in the accompanying independent and dependent claims. Features of the dependent claims may be -6 -combined with features of the independent claims as appropriate, and in combinations other than those explicitly set out in the claims.
Where an apparatus feature is described as being operable to provide a function, it will be appreciated that this includes an apparatus feature which provides that function or which is adapted or configured to provide that function.
BRIEF DESCRIPTION OF THE DRAWINGS
Embodiments of the present invention will now be described further, with reference to the accompanying drawings, in which: Figure 1 illustrates schematically a multistage vacuum pump having an overpressure valve according to one embodiment.
DESCRIPTION OF THE EMBODIMENTS
Before discussing the embodiments in any more detail, first an overview will be provided. Embodiments provide an over-pressure relief valve for use in a multistage pump such as a vacuum pump or compressor. The over-pressure relief valve couples between two stages of the multistage vacuum pump. Typically, the valve couples one of the so-called low vacuum stages which are proximate the exhaust of the multistage vacuum pump with one of the so-called high vacuum stages of the multistage vacuum pump which are proximate the inlet of the multistage vacuum pump. The stages of the multistage vacuum pump typically share a common rotor which is held in axial position by a preloaded force provided by, for example, a spring. This spring helps to ensure that the correct axial position is maintained to prevent clashing between the axial ends of the rotor lobes in each of the stages and the enclosing axial ends of the stator enclosures. However, when an increase in pressure occurs due to, for example, a blockage then the backpressure caused by the compressed fluid within at least one of the stages can overcome the biasing force of the spring, which can cause an undesirable axial movement of the rotor and clashing between the rotor and the stator. However, providing an over-pressure valve coupling between the stages, which activates when greater than a desired pressure is experienced, -7 -allows fluid flow from the lower vacuum stage to the higher vacuum stage and reduces the pressure within the lower vacuum stage which prevents the biasing spring from being overcome and avoids clashing between the rotor and the stator.
Multistage Vacuum Pump Figure 1 illustrates schematically a multistage vacuum pump 10 according to one embodiment. The multistage vacuum pump 10 has an inlet 20 which is coupled with a high vacuum apparatus (not shown). The inlet 20 is coupled to a first high io vacuum stage 30 which begins to compress the fluid received via the inlet 20 and outputs the compressed fluid to a second high vacuum stage 40. The second high vacuum stage 40 compresses the fluid and outputs the compressed fluid to a third high vacuum stage 50. The compressed fluid output by the third high vacuum stage 50 is provided to a first low vacuum stage 60 where it is compressed further. The fluid output by the first low vacuum stage 60 is provided to a second low vacuum stage 70 where it is further compressed. The compressed fluid output by the second low vacuum stage 70 is provided to a third low vacuum stage 80 where it is further compressed. The compressed fluid output by the third low vacuum stage 80 is provided to a fourth low vacuum stage 85 where it is further compressed, this time to at least atmospheric pressure and is output through an exhaust 90.
The multistage vacuum pump 10 in this example is a roots-type vacuum pump with a common rotor shared by each of the stages. The first high vacuum stage 30, second high vacuum stage 40 and third high vacuum stage 50 collectively form a high vacuum stage group 100. The first low vacuum stage 60, the second low vacuum stage 70, the third low vacuum stage 80 and the fourth low vacuum stage 85 together form a low vacuum stage group 110. The low vacuum stage group 110 is characterized by providing relatively high compression compared to the high vacuum stage group 100 and provides for above-ambient pressure so that the compressed fluid can be pushed out of the exhaust 90. The high -8 -vacuum stage group 100 is characterized by providing relatively low compression compared to the low vacuum stage group 110.
The vacuum level at the first high vacuum stage 30 is higher (that is the pressure is lower) than the above-ambient pressure output from the fourth low vacuum stage 85 with the vacuum level decreasing (and pressure and compression increasing) along each stage from the first high vacuum stage 30 to the fourth low vacuum stage 85.
The common rotor shared by the multistage vacuum pump 10 has differing radial and axial dimensions in the different stages. In this example, the radial and axial dimensions of the high vacuum stage group 100 are larger than those of the low vacuum stage group 110. A preload spring (not shown) biases the rotor with a preload force to resist movement of the rotor at least along the axial direction towards the inlet.
Over-pressure Valve An over-pressure valve 120 is provided which couples with the exhaust 90 using a conduit 130. The over-pressure valve 120 also couples via a conduit 140 with the input to the second high vacuum stage 40. The over-pressure valve 120 is biased into a closed position to prevent flow of compressed fluid from the exhaust 90 through the coupling conduit 130, through the over-pressure valve 120 and through the coupling conduit 140 to the inlet of the second high vacuum stage 40 under normal operating conditions.
However, the bias force within the over-pressure valve 120 is configured to be overcome when the pressure of the fluid at the exhaust 90 and conveyed to the over-pressure valve 120 via the conduit 130 increases to a threshold amount, due to, for example, a blockage in the fluid path through the exhaust. In those circumstances, the over-pressure valve 120 opens, allowing the fluid to be conveyed from the exhaust 90 to the inlet of the second high vacuum stage 40, thereby reducing the pressure at the exhaust 90. The pressure required to -9 -actuate the over-pressure valve 120 is set to a level which is below the pressure which would overcome the preload force on the rotor and cause the rotor and stator to clash.
Although in this example the over-pressure valve 120 couples the exhaust 90 back to the inlet of the high vacuum stage 40, it will be appreciated that this need not be the case. Instead, any of the stages may be coupled with another of the stages and the over-pressure valve may then operate resulting from an overpressure due to blockage in any of the downstream stages. Typically, one of the io lower vacuum stage group 110 is coupled with one of the higher vacuum stage group 100. Preferably, the exhaust 90 is coupled with the inlet 20 via the overpressure valve 120.
Although illustrative embodiments of the invention have been disclosed in detail herein, with reference to the accompanying drawings, it is understood that the invention is not limited to the precise embodiment and that various changes and modifications can be effected therein by one skilled in the art without departing from the scope of the invention as defined by the appended claims and their equivalents.
-10 -
REFERENCE SIGNS
multistage vacuum pump 10 inlet 20 first high vacuum stage 30 second high vacuum stage 40 third high vacuum stage 50 first low vacuum stage 60 second low vacuum stage 70 third low vacuum stage 80 exhaust 90 high vacuum stage group 100 low vacuum stage group 110 over-pressure valve 120 conduit 130, 140

Claims (9)

  1. CLAIMS1. A multistage vacuum pump having a plurality of stages, comprising: at least one higher vacuum stage which is operable to receive fluid from a 5 high vacuum device to be compressed; at least one lower vacuum stage which is operable to receive compressed fluid from said at least one higher vacuum stage; and an over-pressure device operable to selectively couple said at least one lower vacuum stage with said at least one higher vacuum stage.
  2. 2. The multistage vacuum pump of claim 1, wherein said over-pressure device is operable to selectively couple said at least one lower vacuum stage with said at least one higher vacuum stage to convey at least some of said compressed fluid from said at least one lower vacuum stage to said at least one higher vacuum stage.
  3. 3. The multistage vacuum pump of claim 1 or 2, said over-pressure device is operable to selectively couple said at least one lower vacuum stage with said at least one higher vacuum stage when a pressure differential across said over-20 pressure device exceeds a threshold amount.
  4. 4. The multistage vacuum pump of any preceding claim, wherein said overpressure device comprises a valve biased closed by a biasing force and said plurality of stages comprise a common rotor urged into position by an urging force, wherein said urging force exceeds said biasing force.
  5. 5. The multistage vacuum pump of any preceding claim, comprising a plurality of lower vacuum stages, each being a sequentially decreasing lower vacuum stage and wherein said over-pressure device is operable to couple other than a highest vacuum stage of the lower vacuum stages with said at least one higher vacuum stage.
  6. -12 - 6. The multistage vacuum pump of any preceding claim, comprising a plurality of lower vacuum stages, each being a sequentially decreasing lower vacuum stage and wherein said over-pressure device is operable to couple a lowest vacuum stage of the lower vacuum stages with said at least one higher vacuum stage.
  7. 7. The multistage vacuum pump of any preceding claim, comprising a plurality of higher vacuum stages, each being a sequentially decreasing higher vacuum stage and wherein said over-pressure device is operable to couple said at least one lower vacuum stage with other than a lowest vacuum stage of the higher vacuum stages.
  8. 8. The multistage vacuum pump of any preceding claim, comprising a plurality of higher vacuum stages, each being a sequentially decreasing higher vacuum stage and wherein said over-pressure device is operable to couple said at least one lower vacuum stage with a highest vacuum stage of the lower vacuum stages.
  9. 9. A method, comprising: providing a multistage vacuum pump having a plurality of stages, comprising at least one higher vacuum stage which is operable to receive fluid from a high vacuum device to be compressed, and at least one lower vacuum stage which is operable to receive compressed fluid from said at least one higher vacuum stage; and selectively coupling said at least one lower vacuum stage with said at least one higher vacuum stage.
GB1919167.5A 2019-12-23 2019-12-23 Multi-stage vacuum pump Pending GB2590666A (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
GB1919167.5A GB2590666A (en) 2019-12-23 2019-12-23 Multi-stage vacuum pump
PCT/EP2020/087056 WO2021130117A1 (en) 2019-12-23 2020-12-18 Multi-stage vacuum pump

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB1919167.5A GB2590666A (en) 2019-12-23 2019-12-23 Multi-stage vacuum pump

Publications (2)

Publication Number Publication Date
GB201919167D0 GB201919167D0 (en) 2020-02-05
GB2590666A true GB2590666A (en) 2021-07-07

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
GB1919167.5A Pending GB2590666A (en) 2019-12-23 2019-12-23 Multi-stage vacuum pump

Country Status (2)

Country Link
GB (1) GB2590666A (en)
WO (1) WO2021130117A1 (en)

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
TW201111634A (en) * 2009-09-30 2011-04-01 Kashiyama Ind Ltd Positive displacement dry vacuum pump
GB2575270A (en) * 2018-07-03 2020-01-08 Edwards Ltd Interstage valve

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB0518995D0 (en) * 2005-09-16 2005-10-26 Boc Group Plc Vacuum pump
GB2499217A (en) * 2012-02-08 2013-08-14 Edwards Ltd Vacuum pump with recirculation valve

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
TW201111634A (en) * 2009-09-30 2011-04-01 Kashiyama Ind Ltd Positive displacement dry vacuum pump
GB2575270A (en) * 2018-07-03 2020-01-08 Edwards Ltd Interstage valve

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Publication number Publication date
WO2021130117A1 (en) 2021-07-01
GB201919167D0 (en) 2020-02-05

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