U.S. patent application number 14/474536 was filed with the patent office on 2015-03-05 for vacuum pump and arrangement with vacuum pump.
The applicant listed for this patent is Pfeiffer Vacuum GmbH. Invention is credited to Jan Hofmann, Michael Schweighoefer, Tobias Stoll, Robert Watz.
Application Number | 20150064033 14/474536 |
Document ID | / |
Family ID | 51383656 |
Filed Date | 2015-03-05 |
United States Patent
Application |
20150064033 |
Kind Code |
A1 |
Stoll; Tobias ; et
al. |
March 5, 2015 |
VACUUM PUMP AND ARRANGEMENT WITH VACUUM PUMP
Abstract
A vacuum pump includes a housing having an axial inlet a pumping
unit including a stator, a rotor rotatably supported in the stator,
and a drive for driving the rotor. At least one housing part which
has at least one outlet, is placed on the housing in an axial
direction and is connected with the housing.
Inventors: |
Stoll; Tobias; (Hohenahr,
DE) ; Schweighoefer; Michael; (Schoeffengrund,
DE) ; Watz; Robert; (Weilburg, DE) ; Hofmann;
Jan; (Gruenberg, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Pfeiffer Vacuum GmbH |
Asslar |
|
DE |
|
|
Family ID: |
51383656 |
Appl. No.: |
14/474536 |
Filed: |
September 2, 2014 |
Current U.S.
Class: |
417/423.4 |
Current CPC
Class: |
F04D 29/522 20130101;
F04D 29/5853 20130101; F04D 19/042 20130101; F04D 19/04 20130101;
F04D 29/668 20130101; F04D 29/601 20130101 |
Class at
Publication: |
417/423.4 |
International
Class: |
F04D 19/04 20060101
F04D019/04 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 4, 2013 |
DE |
102013109637.9 |
Claims
1. A vacuum pump, comprising a housing (2) having an axial inlet
(7); a pumping unit including a stator (5), a rotor (3) rotatably
supported in the stator, and a drive (114) for driving the rotor;
and at least one additional placed-on housing part (10) attachable
to the housing (2) in an axial direction, connectable with the
housing, and having at least one outlet (12).
2. A vacuum pump according to claim 1, wherein the at least one
housing part (10) has at least one radial inlet (11).
3. A vacuum pump according to claim 2, wherein the at least one
radial inlet (11) is provided at an end of the placed-on housing
part (10) remote from the drive.
4. A vacuum pump according to claim 1, wherein the housing (2) of
the vacuum pump (1) has at least one radial inlet (8, 9).
5. A vacuum pump according to claim 1, wherein the at least one
placed-on housing part (10) has a same outer profile as the housing
(2).
6. A vacuum pump according to claim 1, wherein pump-active elements
of the pumping unit are at least partially located in the at least
one placed-on housing part (10).
7. A vacuum pump according to claim 1, wherein the at least one
placed on housing part (10) is free of the pump-active elements of
the pumping unit.
8. A vacuum pump according to claim 1, wherein the housing (2) and
the at least one placed-on component (10) have a total length (L)
of at least 550 mm.
9. A vacuum pump according to claim 1, wherein the housing (2) and
the at least one placed-on component (10) have a total length (L)
of at least 700 mm.
10. A vacuum pump according to claim 1, wherein the inlet (7) of
the housing (2) and the outlet (12) of the at least one placed-on
housing part overlay each other.
11. A vacuum pump according to claim 1, wherein at least one of
thermal sealing element, vibration-isolation sealing element, and
electrical sealing element (21, 22) is provided between the housing
(2) of the vacuum pump (1) and the at least placed-on housing part
(10).
12. A vacuum pump according to claim 1, wherein the vacuum pump (1)
comprises at least one of turbomolecular pump stages and Holweck
pump stages.
13. A vacuum pump according to claim 1, wherein the vacuum pump has
at least two inlets (8, 9, 11).
14. An arrangement comprising a vacuum pump including a housing (2)
having an axial inlet (7), a pumping unit having a stator (5), a
rotor (3) rotatably supported in the stator, and a drive (114) for
driving the rotor, and a pump flange; a chamber (102) having a
chamber flange; means for vacuum-tightly connecting the vacuum pump
and the chamber and including the pump flange and the chamber
flange; wherein the vacuum pump further includes at least one
additional placed-on housing part (10) attachable to the housing
(2) in an axial direction, connectable with the housing, and having
at least one outlet (12) and at least one radial inlet (11)
connectable with the chamber (102).
15. An arrangement according to claim 14, wherein the chamber (102)
comprises a plurality of different chambers (121, 122, 123, 166),
and the at least one radial inlet (11) is connected with at least
one of the different chambers (166).
16. An arrangement according to claim 14, wherein the arrangement
further comprises a force-transmitting structure (165) for
transmitting force from an application point (156) to at least one
operating point provided on the connecting means.
17. An arrangement according to claim 14, further comprising a
mass-spectrometer (124).
18. An arrangement according to claim 14, wherein the arrangement
comprises a receiver, and the housing of the vacuum pump and at
least one placed-on housing part have an outer profile adapted to a
receiver profile.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a vacuum pump and an
arrangement with a vacuum pump.
[0003] 2. Description of the Prior Art
[0004] Vacuum pumps, in particular turbomolecular pumps have at
least one rotor that is arranged in the pump housing. The rotor is
surrounded by a stator package or several stators which are
supported in the housing. Further, a drive, e.g., an electric motor
that drives the at least one rotor, is also arranged in the pump
housing. Usually, the drive shaft is arranged coaxially with the
rotor axis.
[0005] With the turbomolecular pumps, high compression ratios can
be achieved. The turbomolecular pumps have a very small outlet
opening or outlet nipple in comparison with an inlet opening or
inlet nipple. Usually, a conduit connects a forevacuum pump with
the outlet nipple.
[0006] Arrangements which include vacuum pumps and recipients,
which further refer to as chambers, present a number of
requirements, with regard to their geometrical design. E.g., with
mass-spectrometers, it is desirable that the entire system has
compact dimensions. Often, this results in such positioning of the
vacuum pump in the end apparatus that its access is noticeably
limited. Despite this, the servicing of the vacuum pump, e.g.,
preventive replacement of shaft bearings, should be possible.
[0007] According to the state of the art (EP 2 228 540 A2), there
is provided an arrangement with a vacuum pump having a pump flange.
The arrangement also has a chamber flange and flange connecting
means for vacuum-tight connection of the chamber and the vacuum
pump. The arrangement also includes a force transmitting structure
for transmitting force from an application point to an operating
point located in the flange connection means.
[0008] This means that the vacuum pump is usually arranged in a
receiver provided in the arrangement to this end. The receiver can
be formed as some type of a rail system. The pump flange and the
chamber flange are vacuum-tightly connected with each other. Here,
the inlet openings of the pump are so arranged that they are
aligned with outlet openings of the chamber, overlaying each other.
This state-of-the art pump can be easily extracted from the
arrangement after loosening respective connection and connection
means, e.g., to effect a preventive replacement of shaft
bearings.
[0009] These state-of-the art arrangements should meet
customer-specific requirements with regard to position of the
chamber outlets and the geometry of the pump receiver.
[0010] In a system with several suction openings for different
pressure levels, as known in practice, several separate pumps are
used. In particular, with mass-spectrometers with time-of-flight
systems, the increased distances between different suction openings
are observed. The time-of-flight mass-spectrometers form a
sub-class of mass-spectrometers.
[0011] In practice, with the time-of-flight mass-spectrometers,
so-called split-flow pumps are used. Split-flow pumps represent
vacuum pump systems for multi-stage gas inlet systems disclosed,
e.g., in DE 43 31 589 A1.
[0012] These state-of-the art split-flow pumps usually have a
constructional length of 500 mm. If, however, the suction openings
are spaced by a large distance, as it is known from practice, the
pump houses, which are long enough to bridge large distances
between the suction openings, can be produced only with very
expensive machine-tools.
[0013] The object of the invention is to so improve the
state-of-the art vacuum pumps and arrangements with vacuum pumps
that the customer-specific requirement can be realized in a simpler
and more cost-effective manner, and that cheaper vacuum pumps with
a large length are produced.
SUMMARY OF THE INVENTION
[0014] The object of the invention is achieved with a vacuum pump
including a housing having an axial inlet a pumping unit including
a stator, a rotor rotatably supported in the stator, and a drive
for driving the rotor, and at least one additional placed-on
housing part attachable to the housing in an axial direction,
connectable with the housing, and having at least one outlet.
[0015] The advantage of the inventive vacuum pump consists in that
with the additional housing part placed on in the axial direction,
a greater constructional length of the vacuum pump which is often
required in the field, can be realized. In addition, a standard
vacuum pump can be used, and the placed-on housing part then is
provided with dimensions capable to meet customer-specific
requirements.
[0016] In addition, the vacuum pumps can be formed with
through-housings having greater lengths then it was possible with
tools known up to now. Namely, the state-of-the art machine-tools
limit the constructional length of the housing.
[0017] With the provision of at least one additional housing part,
in principle, any arbitrary length can be provided.
[0018] The placed-on housing part has an advantage, in comparison
with, e.g., attached tube, that consists in that the diameter and
the outer profile of the housing are formed so that they remain the
same as for the entire vacuum pump, so that flanges, openings, rail
system and the like of the inventive pump can be used in
arrangements, e.g., including a mass-spectrometer.
[0019] In addition the placed-on tubes often have a bent-off
section in order to be able to connect the tube with an outlet of a
pump chamber arranged radially with respect to the longitudinal
axis of the pump. Because of the bent-off section, a state-of-the
art vacuum pump with a placed-on tube cannot be received in
existing receivers.
[0020] According to a particular advantageous embodiment of the
invention, the at least one placed-on part has at least one radial
inlet.
[0021] This radial inlet serves for connection, with an outlet of a
pumped chamber of the arrangement in which the vacuum pump is
arranged.
[0022] If the arrangement has several chambers, advantageously, the
placed-on part has a corresponding number of inlets which overlay
respective outlets of the chambers.
[0023] According to a further advantageous embodiment of the
invention, the at least one radial inlet of the placed-on housing
part is provided at the end of the placed-on housing part remote
from the drive.
[0024] Arrangements with mass-spectrometers having time-of flight
systems often have increased distances between different suction
openings. Because in the placed-on housing part, customer-specific
radial inlets can be formed, it is advantageous when at least one
radial inlet or the last radial inlet is provided at the end remote
from the drive, i.e., at the end of the housing part remote from
the pump-active structures.
[0025] According to a further advantageous embodiment of the
invention, the housing of the vacuum pump has at least one radial
inlet. This means that the vacuum pump itself has at least one
radial inlet provided in the housing to which the additional
housing part is attached.
[0026] According to a further advantageous embodiment of the
invention, the at least one placed-on housing part has an outer
profile at least partially similar to that of the housing. Thereby,
it is insured that the vacuum pump housing and the placed-on
housing part have an outer profile of a one-piece housing. Thereby,
it becomes possible to particularly advantageously arrange the
vacuum pump in a receiver of an arrangement with
mass-spectrometer.
[0027] Identical outer profiles of a housing and a placed-on
housing part can advantageously be interrupted by a necking.
[0028] According to yet another advantageous embodiment of the
invention, pump-active structures of the vacuum pump can at least
partially be located in the placed-on housing part. There also
exists a possibility to arrange a bearing star for a rotor bearing
in the placed-on housing part.
[0029] Other components likewise can be provided in the housing
part.
[0030] According to another embodiment of the invention, no
pump-active structures of the vacuum pump are arranged in the
placed-on housing part. In this case, the at least one placed-on
housing part forms a pure extension of the vacuum pump housing.
[0031] The housing and at least one placed-on housing part have
advantageously a total length of at least 550 mm. Vacuum pump
housings with a length less than 500 mm can be manufactured with
usual expenses by conventional machine-tools.
[0032] The invention, advantageously, permits to achieve lengths of
more than 550 mm, e.g., lengths of more than 700 mm can be
practically obtained.
[0033] According to yet further advantageous embodiment of the
invention, the inlet openings of the housing and the outlet
openings of the placed-on housing part are so formed that they
overlay each other. Thereby, it is insured that the placed-on
housing part functions as an extension of the vacuum pump
housing.
[0034] According to a still further embodiment of the invention,
two placed-on housing parts placed one onto the other can be
provided, with the outer opening of the second housing part
overlaying the inlet opening of the first housing part, whereby a
further extension of the vacuum pump housing becomes possible.
[0035] According to another particularly advantageous embodiment of
the invention, at least one thermally isolating sealing element,
and/or vibration-isolating sealing element, and/or electrically
isolating sealing element is provided between the housing of the
vacuum pump and the placed-on housing part, and/or between two
placed-on housing parts when two housing parts are placed one upon
the other. This function can be incorporated in a particularly
formed sealing element.
[0036] This embodiment permits, e.g., to achieve a thermal
separation of housing parts. Also, electrical isolation and/or
vibration-isolation also become possible.
[0037] According to an advantageous embodiment of the invention,
the vacuum pump is formed as a turbomolecular pump.
[0038] However, it is also possible to provide other types of pumps
with the inventive housing extension.
[0039] According to another embodiment, the vacuum pumps can be
formed with two gas inlets. This type of pumps is called split-flow
pumps. This type of pumps are often used in arrangements with
multi-stage gas inlet system, e.g., with mass-spectrometers. It is
particularly in this arrangements, it is often desirable to have
housings adapted to customer-specific requirements.
[0040] The vacuum pump can have, e.g., at least one turbomolecular
pump stage and/or at least one Holweck pump stage. The at least one
Holweck pump stage usually is arranged downstream of the at least
one turbomolecular pump stage in the gas flow direction. The gas
inlets are advantageously arranged in front of, between, or behind
the turbomolecular pump stages and/or Holweck pump stages.
[0041] An inventive arrangement comprises a vacuum pump including a
housing having an axial inlet, a pumping unit having a stator, a
rotor rotatably supported in the stator, and a drive for driving
the rotor, and a pump flange; a chamber having a chamber flange;
means for vacuum-tightly connecting the vacuum pump and the chamber
and including both the pump flange and the chamber flange; with the
vacuum pump further including at least one additional placed-on
housing part attachable to the housing in an axial direction,
connectable with the housing, and having at least one outlet and at
least one radial inlet connectable with the chamber.
[0042] With this embodiment of the arrangement that includes a
vacuum pump, the vacuum pump can be used in an arrangement with
several suction openings spaced from each other, without
particularly high machining and finishing costs in housing
manufacturing.
[0043] According to a particularly advantageous embodiment of the
invention, the arrangement has a force-transmitting structure for
transmitting force from an application point to at least one
operating point provided on the connecting means. This
force-transmitting structure is disclosed in EP 2 228 540 A2.
[0044] As discussed, the inventive arrangements are particular
advantageous when used with mass-spectrometers because in these
arrangements several gas inlets are available which, under
circumstances, can form suction openings spaced from each other by
large distances.
[0045] According to a yet particularly advantageous embodiment of
the invention, the housing of the vacuum pump and the at least one
placed-on housing part have an outer profile adapted to a receiver
provided in the arrangement. Thereby, it became possible to fit the
vacuum pump with the placed-on housing part in an available
structure of the arrangement. The arrangement receivers for vacuum
pump housing are so formed that they are adapted to the outer
profile of the vacuum pump housings. In this case, it is
advantageous when the placed-on housing part has the same outer
profiled to insure fitting of the housing with the placed-on
housing part in the receiver.
[0046] Basically, there exists also a possibility that the
placed-on housing part is offset relative to the vacuum pump
housing. This embodiment is formed in response to corresponding
requirements specified by the customer.
[0047] Because of the tolerances of separate housing parts and form
and position deviations of the housings and the at least one
housing part during the fitting process, it is advantageous to
provide the bearing of the high vacuum side in the vacuum pump
housing. In this case, the tolerances of the placed-on housing part
can be greater.
[0048] Advantageously, the inventive pump is secured in the
arrangement with a rail system. The rail system enables mounting
and dismounting of the vacuum pump from one side by axial push-in
or pull-out, as described in EP 2 228 540 A2. The pump access then
must be provided only from one side for carrying out mounting and
dismounting, whereby the system can be compactly formed, e.g., with
smaller costs of the pump or the pump replacement.
[0049] Advantageously, the regions between the sealing planes are
formed complementary to each other so that the housing is not
subjected to pressure or non-acceptably deformed because of
crowning and like position errors.
[0050] By greater spacing of the radial suction openings in the
placed-on housing part with respect to the housing, it became
possible to subject, in particular, the high vacuum region of the
pump to high temperatures. The large surface and the length of the
at least one placed-on housing part positively influence the
temperature behavior of the pump.
[0051] Due to use of several parts, it became possible, in
addition, to realize a thermal separation of the housing part or
parts from the vacuum pump housing. This can be carried out by
reduction of the contact surfaces or by using isolating
intermediate elements or sealing elements. An electrical isolation
or vibration isolation can also be realized.
[0052] The invention made possible a modular construction, with the
vacuum pump housing forming a base of the pump with different
housing extensions, i.e., with placed-on housing parts having
different lengths. It is also possible to provide the base pump
with a cover instead of an extension.
[0053] The novel features of the present invention, which are
considered as characteristic for the invention, are set forth in
the appended claims. The invention itself, however, both as to its
construction and its mode of operation, together with additional
advantages and objects thereof, will be best understood from the
following detailed description of preferred embodiments, when read
with reference to the accompanying drawings which show several
exemplary embodiments of the inventive vacuum system.
BRIEF DESCRIPTION OF THE DRAWINGS
[0054] The drawings show:
[0055] FIG. 1 a longitudinal cross-sectional view of a vacuum pump
with a total of three inlets;
[0056] FIG. 2 a longitudinal cross-sectional view of a vacuum pump
with a total of two inlets;
[0057] FIG. 3 a longitudinal cross-sectional view of a vacuum pump
without pump-active structures;
[0058] FIG. 4 a perspective view of a vacuum pump;
[0059] FIG. 5 a longitudinal cross-sectional view of a connection
between a housing and a housing part;
[0060] FIG. 6 a longitudinal cross-sectional view of a connection
between a housing and a housing part according to another
embodiment of the present invention;
[0061] FIG. 7 a longitudinal cross-sectional view of a connection
between a housing and a housing part according to yet another
embodiment of the present invention;
[0062] FIG. 8 a cross-sectional view of a screw connection between
a housing and a housing part;
[0063] FIG. 9 a cross-sectional view of an arrangement with
chambers and a vacuum pump that represents an integrated
system;
[0064] FIG. 10 a cross-sectional view of a flange connection along
line I-I' in FIG. 9; and
[0065] FIG. 11 a cross-sectional view of a flange connection along
line II-II' in FIG. 9.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0066] FIG. 1 shows a vacuum pump 1 having a housing 2. The vacuum
pump 1 has a rotor 3 carrying rotor vanes 4. The rotor vanes 4
alternate with stator vanes 5 and form different vacuum pump stages
of the pump 1.
[0067] At the high-vacuum side, the rotor 3 is supported by a
bearing star 6. For the sake of clarity the bearing is not shown.
At the forevacuum side, the rotor 3 is likewise supported by
bearings, e.g., ball bearings.
[0068] The housing 2 of the vacuum pump has an axial inlet 7. In
addition, there are provided two radial inlets 8 and 9.
[0069] On the housing 2, an additional housing part 10 is arranged
having a further radial inlet 11. The housing part 10 has the same
cross-section and the same outer profile as the housing 2. An
outlet 12 of the housing part is so formed that it completely
overlays the inlet 7 of the housing 2.
[0070] In addition, the housing 2 has a radial outlet 13 that can
be connected with a forevacuum pump (not shown).
[0071] The pump-active structures of the rotor 3, the rotor vanes
4, the stator vanes 5, the bearing star 6 are completely arranged
in the housing 2 according to FIG. 1. The placed-on housing part
forms an extension of the housing 2. With this arrangement, it is
possible to achieve a total length L of the housing 2 and the
placed-on housing part 10 of at least 550 mm, advantageously of at
least 700 mm. Thereby, it becomes possible to remove the suction
opening 11 (inlet 11) relatively far from the suction openings 8, 9
(inlets 8, 9), without a need to manufacture the housing 2 with
expensive machine-tools when the housing is formed as a one-piece
member.
[0072] An interface 19 is provided between the housing 2 and the
housing part 10, as discussed with reference to FIGS. 5 through
8.
[0073] FIG. 2 likewise shows a vacuum pump 1 with a housing 2 and a
housing part 10.
[0074] The same components are designated with the same reference
numerals and would not be precisely described again. According to
this embodiment, the housing 2 has only one radial inlet 9.
[0075] The placed-on housing part 10 increases the length of the
housing 2 so that the combined length of the housing 2 and the
placed-on component 10 is almost twice of the length of the housing
2.
[0076] As shown in FIG. 2, a portion of the pump-active structures
is located in the placed-on housing part 10. Thus, e.g., the
bearing star 6 and the high-vacuum pump stage are located in the
housing part 10.
[0077] FIG. 3 shows a further vacuum pump 1 without any pump-active
structures in the housing 2. The housing 2 has inlets 8, 9 and a
radial outlet 13. The housing part 10 has a radial inlet 11. In
addition, the housing 2 has a necking 14 in order to reduce the
heat flow from high vacuum to the rotor or the housing 2.
[0078] FIG. 4 shows a vacuum pump 1 with a housing 2 and the
placed-on housing part as well as with the inlets 8, 9 and 11. As
shown in FIG. 4 the housing 2 and the housing part 10 have the same
outer profile. E.g., cooling ribs 15 of the housing 2 continue as
cooling ribs 16 of the housing part 10. A necking 14 is also
clearly shown in FIG. 4. In addition, on the housing 2 and the
housing part 10, there are provided strips 17, 18 which insure an
additional stabilization of the housing 2 and the housing part 10
relative to each other and over the entire length of the vacuum
pump 1.
[0079] The connection of the housing 2 and the housing part 10 is
effected over an interface 19. According to FIG. 5, in the
interface 19, there is provided an O-ring seal 20 to achieve a
vacuum-tight connection of the housing 2 with the housing part
10.
[0080] According to FIG. 6, the interface 19 has, in addition to
the O-ring seal 20, a sealing element 21. The sealing element 20
can be formed as a thermal, and/or vibration-isolating, and/or
electrical sealing element.
[0081] FIG. 7 shows an interface 19 with the O-ring seal 20 and a
sealing element 22 which is likewise formed as a thermal, and/or
vibration-isolating, and/or electrical sealing element.
[0082] FIG. 8 shows a screw connection of the housing 2 and the
housing part 10. The screw connection serves for a vacuum-tight and
mechanical connection of the housing 2 and the housing part 10. The
screw connection consists of a screw 25, a washer 26, and an
elastomeric member 24 for vibration isolation. A sleeve 23 is
provided as a force-transmitting element.
[0083] FIG. 9 shows the arrangement of a vacuum pump 1 in a system
including a vacuum pump 1 and a chamber 102.
[0084] The chamber 102 is formed as a multi-chamber system for
operating with different pumps and has, to that end, a forevacuum
chamber 121, an intermediate chamber 122, another intermediate
chamber 123, and a high-vacuum chamber 166. These chambers are
connected with each other by openings 125, 126, 127 through which,
e.g., a stream of gas particles flows. In the high vacuum chamber
166, there is provided a detector, e.g., a mass-spectrometer 124
which is controlled by a control packaged circuit 136. The chamber
102 has a chamber flange 120 with which the pump flange 110 is
connected.
[0085] The pump flange 110 forms part of the vacuum pump 1 which
also includes a shaft 111 which is rotatably supported, at its
high-vacuum side, by a bearing 113, e.g., by a permanent magnet
bearing. The shaft 111 is rotated by drive 114 so that in the pump
stages 115, 116, compression and suction take place.
[0086] A suction opening 127 connects the inlet of the pump stage
115 with the intermediate chamber 122. The suction opening 128
connects the pump stage 116 with the intermediate chamber 123. The
suction opening 169 connects the pump stage 168 with the
high-vacuum chamber 166.
[0087] The gas enters the vacuum pump 1 through the suction opening
169, is compressed in the pump stage 168 and then is compressed,
together with the gas entering the vacuum pump 1 through the
suction opening 128, in the pump stage 116. A further compression,
together with the gas flowing from the intermediate chamber 122
into the vacuum pump 1 through the suction opening 127, takes place
in the pump stage 115. The outlets of the vacuum pump 1 and the
forevacuum chamber 121 are connected by a vacuum conduit 141 with a
forevacuum pump 140 which further compresses the gas and discharges
it against the atmosphere. The pump stages 115, 116, and 168,
advantageously, are formed as turbomolecular pump stages.
[0088] The vacuum pump 1 and the chamber 102 are arranged in a
stand 130. The vacuum pump 1 is connected with the vacuum-tight
chamber by a flange connection, i.e., via the chamber flange and
the pump flange. The stand 130 also carries the control packaged
circuit 136 of the mass-spectrometer and further components 133,
134, 135, e.g., network elements, calculation unit, and the like.
The frame 130 is covered with lining 131. The vacuum pump 1 and the
chamber 102 are accessible through a hinged lid 132, but other
components, however, are surrounded by the stand 130. The flange
connection is, therefore, accessible with much difficulty and only
from the side adjacent to the hinged lid 132. Mounting and
dismounting of the vacuum pump is only possible from the lid
side.
[0089] The vacuum pump 1 has a housing 2 and a placed-on housing
part 10. The placed-on housing part 10 has the inlet 11 connected
with the suction opening 169. With the placed-on housing part 10,
the vacuum pump has an increased length made possible by the
arrangement shown in FIG. 9.
[0090] The mounting without problems is made possible by a
force-transmitting structure according to FIGS. 10 and 11.
[0091] FIG. 10 shows a cross-sectional view of a force-transmitting
structure 165 transverse to the shaft 111 along line I-I' in FIG.
9. The chamber flange 120 and the pump flange 110 are in contact
with each other. For providing a vacuum-tight connection, a seal
119 that surrounds the suction opening 127, is used. In this
cross-section, in the vacuum pump 1, a distance sleeve 118 which is
provided between the pump stages and spaces their components, and
the last stator disc 117 of the high-vacuum pump stage 168 can be
seen. A connecting screw 151 secures a retaining angle 150 to the
chamber flange. A first expansion member 152 and a second expansion
member 153 are arranged between the retaining angle and the pump
flange.
[0092] FIG. 11 shows an associated cross-sectional view along line
II-II' in FIG. 10 and parallel to the shaft 111. It can be seen
that a portion of the retaining angle 150, the first expansion
member 152 and the second expansion member 153, and a portion of
the pump flange 110 lay in a common plane. The first expansion
member 152 has a wedge surface 158' and the second expansion member
has a wedge surface 158. The wedge surfaces 158 and 158' are so
contact each other that their displacement relative to each other
becomes possible. The displacement is effected by a force-applying
screw 155 that extends through a through-bore in an arm 154 of the
first expansion member, with its threaded part engaging in the
thread of the second expansion member 153. By tightening the screw,
a planar force is produced that displaces the expansion members
152, 153 relative to each other. The action of the wedge surfaces
converts the force direction in an axial direction. As a result, an
axial press-on force 160 is produced in the operating point 159 and
that presses the pump flange 110 and the chamber flange 120 against
each other and that provides, thus, for a vacuum-tight connection.
The expansion members 152, 153 provide for force direction
conversion. Mounting and dismounting of the vacuum pump 1 is
achieved by tightening and loosening the screw 155.
[0093] The expansion member 152, 153 insure transmission of a force
from an application point 156 to the operating point 159 in the
force transmitting structure 165. The force transmission enables to
produce a press-on force at points which are not accessible as a
result of the vacuum pump 1 being surrounded by components
described with reference to FIG. 9. Advantageously, in this
embodiment, in addition to force transmission, force distribution
over the pump flange takes place, so that a uniform pressure is
achieved. With an appropriate number of the wedge surfaces and
their angles, the force distribution of the applied force over the
flange 110 can be adjusted.
[0094] Because the housing 2 and the placed-on housing part 10 have
the same outer profile, as shown in FIG. 4, the vacuum pump 1 can
be mounted in an arrangement shown in FIG. 9 without any problem.
As described with reference to FIGS. 10 and 11, the vacuum pump is
fixedly secured in the arrangement. With the placed-on housing part
10 it becomes possible to meet customized requirements economically
and without problem, as shown in the arrangement of FIG. 9.
[0095] Though the present invention was shown and described with
references to the preferred embodiments, those are merely
illustrative of the present invention and is not to be construed as
a limitation thereof and various modifications of the present
invention will be apparent to those skilled in the art. It is,
therefore, not intended that the present invention be limited to
the disclosed embodiments or details thereof, and the present
invention includes all variations and/or alternative embodiments
within the spirit and scope of the present invention as defined by
the appended claims.
* * * * *