U.S. patent application number 11/919963 was filed with the patent office on 2009-03-12 for vacuum pump arrangement.
Invention is credited to Dirk Kalisch, Heinz-Dieter Odendahl, Robert Stolle.
Application Number | 20090068011 11/919963 |
Document ID | / |
Family ID | 36593111 |
Filed Date | 2009-03-12 |
United States Patent
Application |
20090068011 |
Kind Code |
A1 |
Kalisch; Dirk ; et
al. |
March 12, 2009 |
Vacuum pump arrangement
Abstract
A vacuum pump arrangement, especially a turbomolecular pump
arrangement, comprises a rotor (14) and a stator (16) in a pump
housing (10). The pump housing (10) is connected to a vacuum
chamber housing (26) through a pump flange (10). Retaining elements
(34) are provided for this connection. To avoid a twisting of the
retaining elements (34) in the event of a damage, such as the
blocking of the rotor (14) and the high moments occurring thereby,
the retaining element (34) comprises an anti-twist structure (40)
cooperating with the vacuum chamber housing (26).
Inventors: |
Kalisch; Dirk; (Koln,
DE) ; Stolle; Robert; (Kaarst, DE) ; Odendahl;
Heinz-Dieter; (Koln, DE) |
Correspondence
Address: |
Fay Sharpe LLP
1228 Euclid Avenue, 5th Floor, The Halle Building
Cleveland
OH
44115-1843
US
|
Family ID: |
36593111 |
Appl. No.: |
11/919963 |
Filed: |
May 2, 2006 |
PCT Filed: |
May 2, 2006 |
PCT NO: |
PCT/EP2006/061977 |
371 Date: |
November 6, 2007 |
Current U.S.
Class: |
415/220 |
Current CPC
Class: |
F04D 19/042 20130101;
F04D 29/601 20130101 |
Class at
Publication: |
415/220 |
International
Class: |
F01D 1/00 20060101
F01D001/00 |
Foreign Application Data
Date |
Code |
Application Number |
May 7, 2005 |
DE |
10 2005 020 904.1 |
Claims
1. A vacuum pump arrangement, comprising: a rotor and a stator,
both arranged in a pump housing, a pump flange connected to the
pump housing, and at least one retaining element connected to the
pump housing and to a vacuum chamber housing for fastening the pump
housing to the vacuum chamber housing, the retaining element being
connected to an anti-twist means cooperating with the vacuum
chamber housing.
2. The vacuum pump arrangement of claim 1, wherein the anti-twist
means engages a recess provided in the vacuum chamber housing.
3. The vacuum pump arrangement of claim 1, wherein the retaining
element comprises a fastening element provided in addition to the
anti-twist means.
4. The vacuum pump arrangement of claim 1, wherein the anti-twist
means is additionally designed as another fastening element.
5. The vacuum pump arrangement of claim 1, wherein at least three
retaining elements are provided along the circumference of the pump
flange.
6. The vacuum pump arrangement of claim 1, wherein the pump flange
has a groove in which engages a projection of the retaining
element.
7. The vacuum pump arrangement of claim 1, wherein the vacuum pump
arrangement includes a turbomolecular vacuum pump arrangement.
8. The vacuum pump arrangement of claim 5, wherein the pump flange
is annular.
9. The vacuum pump arrangement of claim 8, wherein the annular
flange defines an annular groove.
10. The vacuum pump arrangement of claim 9, wherein the retaining
element includes a ring segment-shaped projection that is received
in the annular groove.
11. A vacuum pump comprising: a pump housing; a rotor and a stator
disposed in the pump housing; an annular flange extending from the
pump housing, the flange having: a vacuum chamber engaging face,
and an annular groove defined in a face opposite to the vacuum
chamber receiving face.
12. The vacuum pump of claim 11, further including: at least one
retaining element for engaging the face of the annular flange
opposite the vacuum chamber, the retaining element having a
fastening element for fastening the retaining element with the
vacuum chamber and an anti-twist element which blocks the retaining
element from rotating around the fastening element.
13. The vacuum pump of claim 12, wherein the retaining element
includes an arcuate projection that is received in the flange
annular channel.
14. A retaining element for retaining the vacuum pump of claim 11
to a vacuum chamber, the retaining element including: an arcuate
leg that engages the face of the annular flange opposite to the
vacuum chamber; an arcuate projection extending from the arcuate
leg to engage the annular groove; an aperture which receives a
fastening element; and an anti-twist structure that cooperates with
a vacuum chamber housing to block the retaining element from
rotating around the fastening element in response to high moments
resulting from a vacuum pump failure.
Description
BACKGROUND
[0001] The invention is directed to a vacuum pump arrangement, in
particular a turbomolecular pump arrangement.
[0002] Vacuum pumps, such as turbomolecular pumps, for example, are
connected to a vacuum chamber housing to generate a vacuum in a
vacuum chamber. The connection is achieved with a pump flange
connected to the pump housing and with corresponding retaining
elements such as so-called claws, for example. These claws are
connected with the pump flange, a lug of the claw engaging a groove
or flute of the pump flange, for example. The claws are fastened to
the vacuum chamber housing by means of a screw. Since such vacuum
pumps weigh up to 65 kg and the rotor situated in the pump housing
can reach numbers of rotations in the range from 30,000 to 100,000
rpm, safety must meet with high demands. Because of the great
weight and the high rotor speeds, a safe fastening of the vacuum
pump at the vacuum chamber housing has to be guaranteed to exclude
hazards to operating personnel with great certainty. Especially in
the event of a damage by a blocking of the rotor, high moments
instantaneously occur that are transferred from the rotor to the
pump housing via the stator and from the pump housing to the vacuum
chamber housing via the claws. With such high moments, which may be
on the order of several thousand Nm, the pump housing may be
twisted relative to the vacuum chamber housing. This may cause
damages to the vacuum chamber housing in the area where the claws
are mounted. A damage to the vacuum chamber housing is a particular
disadvantage, since in addition to replacing the vacuum pump, it is
also necessary to repair the vacuum chamber housing. This does not
only incur high costs, but may also interrupt production possibly
for a longer time. It could possibly also happen that the claws
break completely at the pump flange and that the vacuum pump is no
longer held to the vacuum chamber housing so that the vacuum pump
can drop. Besides damages to the vacuum chamber housing, this
causes a high risk of injuries to the operating personnel.
[0003] Studies have shown that the above problems can occur
especially with flange diameters of and larger than 160 mm.
[0004] It is an object of the present invention to increase the
safety of vacuum pump arrangements in cases of damage.
SUMMARY
[0005] The present vacuum pump arrangement, which is a
turbomolecular pump arrangement, in particular, especially
comprises a pump of great weight and/or high speeds of rotation of
the rotor. The vacuum pump arrangement has a pump housing in which
a rotor and a stator are arranged. Connected to the pump housing is
a pump flange that may also be configured directly as a part of the
housing. Retaining elements are provided for fastening the pump
housing to a vacuum chamber housing. According to the invention, at
least one retaining element has an anti-twist means cooperating
with the vacuum chamber housing. Providing such an anti-twist means
ensures that in case of a damage, especially upon an instantaneous
blocking of the rotor, no twisting of the retaining elements such
as the claws will occur due to the occurring high moments. This
especially avoids a loosening of the connection between the pump
flange and the vacuum chamber housing so that the safety is
enhanced. Further, the risk of a damage to the vacuum chamber
housing in the region of the fastening of the retaining element is
reduced.
[0006] Preferably, at least one retaining element with a present
anti-twist means is provided. Preferably, two, especially
oppositely arranged retaining elements with an anti-twist means are
provided. Here, the present retaining element with an anti-twist
means can be combined with conventional single retaining elements.
Preferably, a plurality of retaining elements with an anti-twist
means are provided, especially (together) with at least three
retaining elements distributed along the circumference of the pump
flange. The pump flange is preferably of annular shape.
[0007] As an anti-twist means, the retaining element may have a pin
preferably engaging a recess or bore provided at the pump chamber
housing. Additionally, the retaining element preferably has a
fastening element, such as a screw. A preferred embodiment of the
present retaining element thus comprises an anti-twist means, e.g.
in the form of a pin engaging a recess, and a fastening element
screwed into a thread provided in the vacuum chamber housing. In
another preferred embodiment, the anti-twist means is also designed
as a fasting element, especially a screw, so that the present
retaining element has at least two, especially identically designed
fastening elements. Since both fastening elements engage recesses,
such as threaded bores, in the vacuum chamber housing, both
fastening elements serve both fastening and anti-twist
purposes.
[0008] The pump flange connected to the pump housing or formed as a
part of the pump housing preferably comprises an annular groove.
This groove may be discontinuous, but preferably extends along the
entire circumference. The retaining elements preferably have a
projection, especially in the shape of a segment of an annulus,
engaging the groove. This substantially facilitates the mounting of
the pump since the position of the pump housing relative to the
vacuum chamber housing can be varied without having to change the
position of the retaining elements.
[0009] Preferably, the radius of the groove substantially
corresponds to the radius of the projections. In particular, this
has the advantage that upon the occurrence of a very high moment in
a case of damage the pump housing can rotate with respect to the
retaining elements as soon as the forces acting due to the existing
moment between the pump flange and the projections are greater than
the frictional forces in this region.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] The following is a detailed description of a preferred
embodiment of the invention with reference to the accompanying
drawings.
[0011] In the Figures:
[0012] FIG. 1 is a schematic sectional view of a vacuum pump
arrangement,
[0013] FIG. 2 is a schematic perspective view of a pump
housing,
[0014] FIG. 3 is a schematic perspective view of a retaining
element of the present invention, and
[0015] FIG. 4 is a schematic top plan view on a part of a vacuum
pump arrangement with a retaining element according to prior art in
a case of damage.
DETAILED DESCRIPTION
[0016] A vacuum pump arrangement comprises a pump housing 10 in
which a rotor 14 rotating about a longitudinal axis 12 is arranged.
Stator blades 16 connected to the housing 10 are disposed between
the individual rotor blades 14. The rotor 14 is rigidly connected
to a drive shaft 20 through a connecting element 18. The stator 16
is correspondingly rigidly connected to the housing 10 through a
connecting element 22.
[0017] To create a vacuum in a vacuum chamber 24, the housing is
fastened to a vacuum chamber housing 26 in the region of an opening
28.
[0018] For fastening, the housing has a pump flange 30 which in the
embodiment illustrated is annular. The pump flange 30 has a
L-shaped cross section so that an annular groove 32 is formed.
[0019] Using a retaining element 34, the pump housing 10 is
fastened to the vacuum chamber housing 26 by the flange 30. To this
end, the retaining element 34 in the embodiment illustrated has a
projection 36, in particular in the shape of a ring segment,
engaging the groove 32 of the pump flange 30.
[0020] As a fastening element, a screw 38 is provided for fastening
the retaining element 34 to the vacuum chamber housing. Here, the
present retaining element 34 (FIG. 2) comprises an anti-twist means
40, both the fastening element 38 and the anti-twist means 40 being
designed as a screw in the embodiment shown. The anti-twist means
40 engages a recess 42, which, in the embodiment illustrated, is a
threaded bore in the vacuum chamber housing 26.
[0021] Since the present retaining elements 34 have an anti-twist
means 40 besides the fastening element 38, it is ensured in the
event of a damage that no twisting of the fastening elements will
occur. Despite the high moments prevailing in case of a damage,
such as in a blocking of the rotor 14, which are transferred from
the rotor 14 to the pump housing 10 via the stator 16, the
retaining elements 34 are not twisted as could happen with
corresponding single retaining elements 44 (FIG. 2).
[0022] The perspective view of the pump housing 10 in FIG. 2 is a
view to the flange side of the pump housing with four retaining
elements 34 of the present invention and four single retaining
elements 44 being provided on the annular flange 30. The present
retaining elements 34 each have an annular projection 36 engaging
the groove 32 of the pump flange (FIG. 1). Further, two screws 38,
40 are provided per retaining element 34 that serve as a fastening
element and an anti-twist means.
[0023] The screws 38, 40 are passed through throughbores 46
provided in the retaining element 34.
[0024] To clearly illustrate the prior art, FIG. 4 shows a single
retaining element 44.
[0025] The single retaining element 44 is fastened in the vacuum
chamber housing 10 by a screw 48. Due to the high moments occurring
in the event of a damage, the pump housing 10 is rotated in the
direction of the arrow 50. Thereby, a single retaining element 4 is
twisted counterclockwise. This can cause damage to the flange 30 as
well as to the vacuum chamber housing 26.
[0026] The invention has been described with reference to the
preferred embodiments. Modifications and alterations may occur to
others upon reading and understanding the preceding detailed
description. It is intended that the invention be constructed as
including all such modifications and alterations insofar as they
come within the scope of the appended claims or the equivalents
thereof.
* * * * *