US3924962A - Molecular pumps of the drum type - Google Patents

Molecular pumps of the drum type Download PDF

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Publication number
US3924962A
US3924962A US503126A US50312674A US3924962A US 3924962 A US3924962 A US 3924962A US 503126 A US503126 A US 503126A US 50312674 A US50312674 A US 50312674A US 3924962 A US3924962 A US 3924962A
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US
United States
Prior art keywords
grooves
thickness
low
discharge
cut
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.)
Expired - Lifetime
Application number
US503126A
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English (en)
Inventor
Louis Maurice
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.)
Alcatel CIT SA
Nokia Inc
Original Assignee
Nokia Inc
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Filing date
Publication date
Application filed by Nokia Inc filed Critical Nokia Inc
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Publication of US3924962A publication Critical patent/US3924962A/en
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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D19/00—Axial-flow pumps
    • F04D19/02—Multi-stage pumps
    • F04D19/04—Multi-stage pumps specially adapted to the production of a high vacuum, e.g. molecular pumps
    • F04D19/044—Holweck-type pumps

Definitions

  • the first consists in reducing the clearance between the rotor and the stator, but that measure leads to the considerable increasing of the cost of machining and reduces appreciably the operational safety of such a pump. Indeed, the least foreign body, the least expansion of a fixed or rotating part and any mechanical deformation cause irremediable seizing of the pump, as happened during the manufacturing of the first pumpt of the Holweck type.
  • the number of grooves is increased in the zones where the compression ratio is sufficiently high for the leakages to become appreciable. A greater number of grooves is therefore observed on the discharge side than on the suction side.
  • the thickness of the low walls between the channels remains substantially constant, there is, according to this method, an increase in the total space kept for the low walls going from the suction end towards the distance end. In this way, from an overall point of view, the transversal impedence afforded to the fluid between the various parallel channels is increased and consequently, the leakages are reduced in the same proportions.
  • the object of the invention is therefore a high vacuum molecular pump comprising a cylindrical drum rotating at high speed with slight play in a stator whose internal face is cylindrical, comprising several helical grooves cut in one or the other of the faces opposite to each other, which are parallel to each other, separated by low walls which end at the output of the pump where the discharge is effected, characterized in that on the one hand, from the suction end to the discharge end, the width of the grooves decreases whereas the thickness of the low walls increases and in that, on the other hand, grooves which are blind on the suction side but open on the discharge side are cut starting from a certain distance from the suction end in the thickness of the low walls.
  • FIG. 1 is a developped view of a groove cut in the rotor (or the stator) according to a first variant of the invention
  • the two low walls limiting the groove 3 on the suction side 4 may be seen at l and at 2, these two low walls extending parallel to each other over a certain length, for example half the height of the drum, up to the point 21 where the compression ratio becomes sufficiently high for a great leakage of fluid to occur between the groove 5 and the groove 3 separated by the low wall 2.
  • the low wall 2 is then extended towards the left and enlarged.
  • a groove 8 parallel to the groove 3 but blind on the suction side is cut in that enlarged low wall 7.
  • the enlarged low wall 7 is prolonged laterally by a portion, itself enlarged, provided with a blind groove 1 1, limited towards the left by the low wall 12.
  • the original groove 3 is replaced by a groove 14 which is clearly narrower, limited by the low walls 1 and 12, whereas two blind grooves 8 and 11 on the suction side 4 lead out from the discharge side 9.
  • the width of the low wall 2 is defined by the distance measured between the right-hand edge of the groove 3 and the left-hand edge of the groove 5.
  • FIG. 2 makes it easier to understand the development of the thickness of the grooves.
  • FIG. 2a shows more particularly a cutaway view of FIG. 1 through AB.
  • the great height of the low walls 1 and 2 limiting the main groove 3 in the vicinity of the suction end will be observed.
  • FIG. 2b corresponding to a cutaway view of FIG. 1 in the vicinity of the discharge end 9, it will be observed that the depth of the main groove 3 has considerably decreased and that the grooves 11 and 8 which are blind on the suction side and open on the discharge side have an even slighter depth, their function being to effect the draining of the flow passing through the play 15 between the low wall 2 and the smooth cylindrical wall 16 of the stator.
  • FIG. 3 shows a second example of embodiment comprising, as in the case of FIG. 1, on the suction side 4, a groove 5 and a groove 6 separated from each other by the low wall 2.
  • the main groove 3 is limited, as previously, by the low walls 1 and 2.
  • That low wall 23 which becomes progressively thicker comprises, as previously, two blind grooves 8' and 10' fulfilling, as previously, the function of draining channels.
  • a high vacuum molecular pump comprising a cylindrical drum rotating with a slight clearance in a stator whose internal face is cylindrical, comprising several parallel helical, main grooves separated by low walls and cut in at least one of the opposite cylindrical faces, wherein; the improvement starting from a certain point, from the suction end to the discharge end, on the one hand the thickness of the low walls increases and on the other hand, grooves which are blind on the suction side and open on the discharge side are cut in the thickness of the low wall.
  • each of the grooves has a greater depth than on the discharge side and the grooves which are blind on the suction side have a depth which is at the most, equal to that of the main grooves.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Non-Positive Displacement Air Blowers (AREA)
  • Applications Or Details Of Rotary Compressors (AREA)
  • Structures Of Non-Positive Displacement Pumps (AREA)
US503126A 1973-09-14 1974-09-04 Molecular pumps of the drum type Expired - Lifetime US3924962A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR7333097A FR2244370A5 (enrdf_load_stackoverflow) 1973-09-14 1973-09-14

Publications (1)

Publication Number Publication Date
US3924962A true US3924962A (en) 1975-12-09

Family

ID=9125050

Family Applications (1)

Application Number Title Priority Date Filing Date
US503126A Expired - Lifetime US3924962A (en) 1973-09-14 1974-09-04 Molecular pumps of the drum type

Country Status (10)

Country Link
US (1) US3924962A (enrdf_load_stackoverflow)
JP (1) JPS5055911A (enrdf_load_stackoverflow)
BE (1) BE819441A (enrdf_load_stackoverflow)
CH (1) CH592818A5 (enrdf_load_stackoverflow)
DE (1) DE2443727A1 (enrdf_load_stackoverflow)
FR (1) FR2244370A5 (enrdf_load_stackoverflow)
GB (1) GB1473713A (enrdf_load_stackoverflow)
IT (1) IT1020719B (enrdf_load_stackoverflow)
NL (1) NL7412212A (enrdf_load_stackoverflow)
SU (1) SU580850A3 (enrdf_load_stackoverflow)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4797068A (en) * 1986-06-12 1989-01-10 Hitachi, Ltd. Vacuum evacuation system
WO2021013979A1 (en) * 2019-07-25 2021-01-28 Edwards Limited Drag pump

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL8105614A (nl) * 1981-12-14 1983-07-01 Ultra Centrifuge Nederland Nv Hoog-vacuum moleculair pomp.
GB2232205B (en) * 1987-12-25 1991-11-13 Sholokhov Valery B Molecular vacuum pump
GB2221255B (en) * 1988-01-05 1991-10-16 Sholokhov Valery B Molecular vacuum pump
WO1989008192A1 (fr) * 1988-02-26 1989-09-08 Nikolai Mikhailovich Novikov Pompe a vide turbomoleculaire
CH676378A5 (enrdf_load_stackoverflow) * 1988-03-30 1991-01-15 Vladimir Pavlovich Sergeev
DE3831258C1 (enrdf_load_stackoverflow) * 1988-09-14 1989-10-12 Alcatel Hochvakuumtechnik Gmbh, 6980 Wertheim, De

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1053637A (en) * 1912-03-02 1913-02-18 John Arthur Hamilton O'reilly Fluid-propelled machine.
US1448079A (en) * 1920-07-08 1923-03-13 Noeggerath Jacob Emil Viscosity pump
US1869106A (en) * 1931-06-12 1932-07-26 Charles J Marchant Rotary engine
US1902439A (en) * 1930-12-30 1933-03-21 Edward T Skeffington Flying worm steam motor
US3794449A (en) * 1971-08-31 1974-02-26 Philips Corp Viscosity pump

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1053637A (en) * 1912-03-02 1913-02-18 John Arthur Hamilton O'reilly Fluid-propelled machine.
US1448079A (en) * 1920-07-08 1923-03-13 Noeggerath Jacob Emil Viscosity pump
US1902439A (en) * 1930-12-30 1933-03-21 Edward T Skeffington Flying worm steam motor
US1869106A (en) * 1931-06-12 1932-07-26 Charles J Marchant Rotary engine
US3794449A (en) * 1971-08-31 1974-02-26 Philips Corp Viscosity pump

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4797068A (en) * 1986-06-12 1989-01-10 Hitachi, Ltd. Vacuum evacuation system
WO2021013979A1 (en) * 2019-07-25 2021-01-28 Edwards Limited Drag pump
CN114127423A (zh) * 2019-07-25 2022-03-01 爱德华兹有限公司 拖曳泵
US11971041B2 (en) 2019-07-25 2024-04-30 Edwards Limited Drag pump

Also Published As

Publication number Publication date
FR2244370A5 (enrdf_load_stackoverflow) 1975-04-11
NL7412212A (nl) 1975-03-18
DE2443727A1 (de) 1975-04-03
JPS5055911A (enrdf_load_stackoverflow) 1975-05-16
GB1473713A (en) 1977-05-18
BE819441A (fr) 1975-03-03
SU580850A3 (ru) 1977-11-15
CH592818A5 (enrdf_load_stackoverflow) 1977-11-15
IT1020719B (it) 1977-12-30

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