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
  • F04D29/00—Details, component parts, or accessories
  • F04D29/26—Rotors specially for elastic fluids
  • F04D29/32—Rotors specially for elastic fluids for axial flow pumps
• • 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 invention relates to an evacuation device with the features of the preamble of claim 1.
• evacuation means having a suction side and a atmospharen horridas paragraphen vacuum pump (roughing pump).
• the suction-side vacuum pump is usually designed as a mechanical, kinetic vacuum pump. These include gas ring pumps, turbo vacuum pumps (axial, radial) as well as molecular and turbomolecular vacuum pumps.
• the gases to be conveyed behave molecularly, that is to say that a directional flow can only be achieved by pump structures which give the individual gas molecules impulses with a preferred direction, the desired direction of flow. Since the gas molecules in the chamber to be evacuated have no preferred direction of movement, only such gas molecules get into the intake port of the connected vacuum pumps that happen to have this direction of movement.
• An " evacuation device of the type concerned here is known from EP-363 503 AI.
• the rotor and stator of the mechanical kinetic vacuum pump are cylindrical.
• the rotor has a conical hub, the diameter of which increases in the direction of the pressure side.
• the width of the webs between the hub and the cylindrical inner surface of the stator accordingly decreases in the direction of the pressure side.
• This solution has the advantage that the inlet cross-section for the molecular behaving gases, ie the suction-side ring surface into which the gases to be conveyed enter, is relatively large, and an evacuation device of the known type is therefore particularly suitable for applications in which there is a requirement for high gas throughputs.
• the object of the present invention is to further improve an evacuation device of the type concerned here with regard to the demand for high gas throughputs.
• the hub is conical, as in the evacuation device according to the prior art.
• evacuation means of Entrance fee 'tsquer- is cut by a multiple greater than in the prior Techni.
• the lines which represent the shape of the outside diameter of the rotor and the inside diameter of the stator in a longitudinal section through the suction-side vacuum pump, are curved in such a way that the slope of the curves increases from the suction side to the pressure side. It is particularly expedient if these lines essentially have the shape of a hyperbola.
• This design of the suction-side vacuum pump ensures. an optimal and above all trouble-free flow of the extracted gases and thus contributes significantly to the goal of improving the gas throughput. Overall, a significant improvement in the power density is achieved, that is to say that the ratio of the performance of the suction-side vacuum pump to its mass is significantly greater than in the prior art. Further advantages and details of the invention will be explained on the basis of exemplary embodiments shown schematically in FIGS.
• FIG. 1 shows a section through a solution with a conical stator and cylindrical rotor hub
• FIG. 2 shows a section through a solution with a conical stator and a conical rotor hub
• Figure 3 shows a section through a solution with an inwardly curved stator and an outwardly curved rotor hub and
• Figure 4 shows a solution according to Figure 3, in which the rotor is shown in view.
• the device according to the invention is denoted by 1, the suction-side vacuum pump by 2 and the vacuum pump on the atmospheric pressure side shown only as a symbol by 3.
• the suction-side pump 2 is designed as a mechanical kinetic vacuum pump. It has a three-part housing 4 with sections 5, 6 and 7.
• the suction-side section 5 is equipped with a flange 8 which forms the suction opening 9 and is used for connection to a system to be evacuated.
• Its inner wall 10 forms the stator component of the mechanical kinetic vacuum pump 2.
• the housing section 5 surrounds the rotor 11. This includes a hub 12 which on its outside carries the structure 13 which effects the gas production.
• These are webs 14 (cf. in particular FIG.
• the at least internally conical housing section 5 is supported on the central, essentially cylindrical housing section 6.
• the lower part of the housing section 5 projects with a lower end section 18 into the housing section 6, to the end of the rotor 11 on the pressure side
• the hub 12 is hollow. In the area of the suction side, it has a disk 23 which separates a pressure-side cavity 24 in the hub 12 from the suction side.
• the lower housing section 7 is approximately cup-shaped and fastened to the middle housing section 6. Together with the pressure-side cavity 24 in the hub
• FIG. 12 shows an engine and storage room.
• Figures 1 to 3 are a drive motor and bearings for the Rotor not shown in detail. These components are known per se.
• the storage suitably consists of magnetic bearings. They are for mechanical kinetic vacuum pumps because of that. high rotor speeds particularly suitable.
• FIG. 4 shows those parts of the drive and bearing system that protrude into the housing section 7.
• An emergency running bearing 25 and components 26 of an eddy current brake (?) Can be seen.
• the outer contour of the rotor 11 and the stator 10 inner surface of the housing 2 are conical, in such a way that the diameter of the outer contour of the rotor and the stator decrease from the suction side to the pressure side. This achieves the desired enlargement both of the entry cross section for the molecules to be removed from the connected recipient and of the peripheral speed of the structure 13.
• the hub 12 of the rotor 11 is also conical, in such a way that the hub diameter increases from the suction side to the pressure side. This measure further increases the entry area for the molecules to be conveyed.
• the outer contour of the rotor 11 and the stator 10 have an inward curvature.
• a significantly improved gas flow through the pump 2 can be achieved by this measure, that is, freed from interference. It is particularly expedient if the stator 10 and the outer contour of the rotor 11 have a hyperbolic course. Result of this measure . is the following calculation:
• the first term describes the Cuette flow and the second term the channel backflow caused by the pressure gradient. All geometry data, with the exception of the channel depth, can be assumed to be essentially constant over the axial length. In addition, the denominator is approximated by 2 in the first term, since the ratio s / h is rather small. The viscosity is also approximated as a variable independent of the pressure. You can therefore write:
• a linear pressure curve in the pump therefore results in a coordinate system with the axis of rotation
• the shape of the rotor hub 12 was initially disregarded in this calculation. It can be cylindrical, conical or curved outwards, as shown in FIGS. 1 to 4. From the point of view of simple manufacture, the conical shape (FIG. 2) is preferable. From the point of view of a possible undisturbed flow, a slight curvature inwards - appropriately also. Hyperbolic - is expedient.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Non-Positive Displacement Air Blowers (AREA)
• Structures Of Non-Positive Displacement Pumps (AREA)
• Applications Or Details Of Rotary Compressors (AREA)

Applications Claiming Priority (3)

Publications (1)

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ID=29557496

Family Applications (1)

Country Status (8)

Families Citing this family (6)

Family Cites Families (13)

• 2002
  • 2002-06-04 DE DE10224604.1A patent/DE10224604B4/de not_active Expired - Fee Related
• 2003
  • 2003-05-16 AU AU2003282471A patent/AU2003282471A1/en not_active Abandoned
  • 2003-05-16 EP EP03783967A patent/EP1509701A1/de not_active Withdrawn
  • 2003-05-16 US US10/517,113 patent/US7264439B2/en not_active Expired - Fee Related
  • 2003-05-16 CN CNB038129620A patent/CN100422565C/zh not_active Expired - Fee Related
  • 2003-05-16 JP JP2004526668A patent/JP4457008B2/ja not_active Expired - Fee Related
  • 2003-05-16 WO PCT/EP2003/005136 patent/WO2004015272A1/de active Application Filing
  • 2003-05-29 TW TW092114552A patent/TWI294946B/zh not_active IP Right Cessation

Non-Patent Citations (1)

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