Patent Description:
Vacuum pumps known in the art comprise a housing wherein a rotor assembly is disposed within the housing and rotated by an electric motor. The rotor assembly comprises at least one rotor element interacting with a stator, wherein the stator is connected to the housing. Further, the housing comprises an inlet and an outlet, wherein due to interaction of the rotor element with the stator element upon rotation of the rotor assembly a gaseous medium is conveyed from the inlet to the outlet.

The majority of known vacuum pumps comprise a flange directly connected to the outer most end of the inlet side of the vacuum pump. Alternatively, so called cartridge pumps are known, wherein the flange is arranged on the opposite side to the inlet at the pump base, wherein the vacuum pump is almost completely inserted into a vacuum apparatus. With the flange the vacuum pump is connected to a vacuum apparatus.

However, in both possibilities the axial position of the vacuum pump with respect to the vacuum apparatus is fixed. The known vacuum pumps do not provide any freedom in design and simply provide the choice whether the pump is completely inserted into the vacuum apparatus or externally attached to it.

In particular, for portable vacuum apparatus such as point of use mass spectrometer systems, the size of the vacuum apparatus needs to be small requiring more degrees of freedom regarding the position of the vacuum pump with respect to the vacuum apparatus.

<CIT> describes a vacuum system to connect a vacuum pump to a vacuum apparatus. There, the vacuum pump comprises a flange surrounded by a collar, wherein a clamping ring provided between the collar and the flange of the vacuum pump fixes the axial position of the vacuum pump relative to the vacuum apparatus.

It is a subject of the present application to provide a vacuum pump providing the possibility for a small and compact design.

The technical problem is solved by a vacuum pump in accordance to claim <NUM> as well as a vacuum system in accordance to claim <NUM>.

The vacuum pump in accordance to the present invention for connecting to a vacuum apparatus comprises a housing having a first end defining an inlet and a second end opposite to the first end. In particular, in the housing a rotor assembly is disposed comprising at least one rotor element wherein the rotor assembly is rotated by an electric motor. Further, the rotor element is interacting with at least one stator element connected to the housing in order to convey a gaseous medium from the inlet to an outlet.

Further, in accordance to the invention the vacuum pump comprises a collar to be connected to a vacuum apparatus. In particular, the collar is directly connected to the vacuum apparatus. The housing comprises at least one positioning element and also the collar comprising at least one positioning element for defining an axial position of the housing relative to the collar. This may provide the advantage that by tayloring the position of at least one positioning element, the axial position of the vacuum pump with respect to the collar can be adjusted. Since the collar is in particular directly connected to the vacuum apparatus, as a consequence also the axial position of the vacuum pump with respect to a vacuum apparatus can be adjusted accordingly.

Preferably the positioning element of the housing is arranged at the first end of the housing. However, the more the positioning element is shifted towards the second end of the housing, the more the vacuum pump is inserted into the vacuum apparatus. In particular, the positioning element is not arranged directly at the first end and also not arranged directly at the second end of the housing, but spaced apart from the first end and the second end which may provide the desired degree of freedom in design of the axial positon of the vacuum pump with respect to the vacuum apparatus.

According to the present invention the housing comprises more than one positioning element. The positioning elements are then distributed along an axial direction of the pump wherein each positioning element is spaced apart from the directly adjacent positioning elements. Since by the positioning elements the axial position of the vacuum pump is defined providing more than one positioning element at the housing of the vacuum pump, this may have the advantage that with one housing different axial positions can be realized without the necessity to rebuild or reconstruct the housing for each individual application of the vacuum pump. Additionally or alternatively, the collar comprises more than one positioning element distributed along an axial direction of the collar in order to define different axial positions in which the housing can be placed with respect to the collar, i. the vacuum apparatus. Preferably the positioning elements of the collar are also separated from each other wherein more preferably the separation of the positioning elements of the collar are identical to the separation of the positioning elements of the housing, in particular if both the housing and the collar comprise more than one positioning element. However, it is also possible to have different separations between the positioning elements of the housing and the collar. Different separation between positioning elements in the collar and positioning elements in the housing provides more relative positioning options than same spacing. Additionally or alternatively also the number of positioning elements of the collar and/or the housing can be equal or different.

This may provide the advantage that either by the positioning elements of the housing or the positioning elements of the collar, different axial positions of the vacuum pump with respect to the vacuum apparatus are feasible with one vacuum pump without the necessity to rebuild or reconstruct for each application.

Preferably the number of positioning elements of the housing and the number of positioning elements of the collar are identical. Alternatively the number of positioning elements of the housing and the number of positioning elements of the collar are different. More preferably one of the number of positioning elements of the housing or the number of positioning elements of the collar is one while the other is larger than one.

Preferably the positioning element is a circumferential groove. In particular, the circumferential groove is arranged at an outer surface of the housing and/or a radially inner surface of the collar. In particular the groove need not to be closed on all three sides but can also be open at one side. Thus, the groove can be built as abutment edge. The vacuum pump further comprises a snap ring, which is disposed in the groove of the housing and the groove of the housing simultaneously for engagement of the respective positioning elements. Thus, the axial position is defined by the position of the circumferential grooves of the housing and the collar, wherein the axial position is fixed by the snap ring. Further, the apparatus may comprise a face opposing the pump inlet face to further define the axial position. In particular, if a snap ring is employed the groove can be built as abutment edge. Then, assembling is performed by advancing the vacuum pump until the snap ring abuts against the abutment edge formed by the groove of the collar. This may provide the advantage that if the axial position of the vacuum pump with respect to the vacuum apparatus needs to be adapted, several positioning elements are provided at the housing and/or the collar, the snap ring will be arranged in another pair of opposing grooves of the housing and the collar.

Preferably, the collar comprises at least one set and preferably more than one set of through holes for receiving a screw for connecting the collar to a vacuum apparatus. Thus, each set of through holes may be adapted to a specific configuration of vacuum apparatus and its individual fastening configurations.

Thus, it may be possible that the collar can be connected to a larger number of different vacuum apparatus without the necessity to reconstruct or redesign the collar for each vacuum apparatus individually. In particular, one specific through hole might belong to more than one set, wherein each set differs at least by one through hole to cover different fastening configurations of different vacuum apparatus.

Preferably the vacuum pump comprises a centering ring arranged at the first end between the housing and the vacuum apparatus. The centering ring maintains a centered position of the vacuum pump with respect to the vacuum apparatus. Preferably, the centering ring has a circular cross-section. However, alternatively the centering ring may also have any other cross-section such as elliptic, rectangular or any other polygonal form in dependence on the form of the inlet of the vacuum pump and/or the port of the vacuum apparatus.

Preferably the centering ring is in direct contact with both the housing and the vacuum apparatus in order to provide a defined centered position.

Preferably the centering ring comprises a first radial abutment face wherein the first abutment face directly abuts against the housing to define a center position. In particular, the first abutment face abuts against a radial surface of the housing.

Preferably the centering ring comprises a second abutment face that directly abuts against a vacuum apparatus and in particular to a radial surface of the vacuum apparatus to maintain a centered position between the vacuum pump and the vacuum apparatus.

Preferably the radius of the first radial abutment face is different than the radius of the second radial abutment face. Thus, the diameter of the connection port of the vacuum apparatus can be adapted to the diameter of the inlet of the vacuum pump. This may provide the advantage that the centering ring may compensate for different inlet diameter of respective vacuum pumps and/or vacuum apparatus.

Preferably the centering ring may be provided in different lengths along the axial direction. Thus, for one vacuum pump to be connected to a certain vacuum apparatus the axial position can be adapted without any redesign of the vacuum pump.

Further, it is subject of the present invention to provide a vacuum system comprising a vacuum pump as previously described and a vacuum apparatus. Therein the vacuum apparatus might be any vessel, spectrometer or apparatus that requires the existence of a certain vacuum.

Preferably a sealing element is placed between the first end of the vacuum pump and the vacuum apparatus in order to provide a vacuum tight seal of the vacuum pump to the vacuum apparatus.

Specific embodiments of the present application will be described in the following with reference to the accompanied drawing.

The vacuum pump <NUM> comprises a housing <NUM> with an inlet <NUM> arranged at a first end <NUM> of the housing <NUM> and an outlet <NUM> arranged at a second end <NUM> of the housing <NUM>. At the outer surface <NUM> of the housing <NUM> three positioning elements are built as grooves 24a, 24b, 24c. Further, a centering ring <NUM> is arranged at the first end <NUM> of the housing <NUM>. The centering ring <NUM> comprises a first radial abutment face <NUM> (<FIG>) and a second radial abutment face <NUM>, wherein the first abutment face <NUM> is in direct contact with the housing <NUM> of the vacuum pump <NUM> and the second abutment face <NUM> is in direct contact with an abutment face of the vacuum apparatus <NUM>. Thus, by the centering ring <NUM> a centered position of the vacuum pump <NUM> with respect to the vacuum apparatus <NUM> is maintained.

Different distances between the housing <NUM> of the vacuum pump <NUM> and the vacuum apparatus <NUM> can be compensated by different centering rings <NUM> which have respectively different length along the axial direction of the pump in correspondence to the housing <NUM> of the vacuum pump <NUM> and the vacuum apparatus <NUM>. Thus, even for the same vacuum pump <NUM> and the same vacuum apparatus <NUM> different axial positions can be chosen with selecting different centering rings having different length along the axial direction of the vacuum pump.

Further, the vacuum pump comprises a collar <NUM> wherein the collar <NUM> comprises in the example of <FIG> four through holes <NUM> to receive screws <NUM>. However, the number and positions of the through holes and screws are not limited. In particular, the collar <NUM> may comprise more than one set of through holes <NUM> to be connected to different fastening configurations of different vacuum apparatuses <NUM>. By the screws <NUM> the collar <NUM> is connected to the vacuum apparatus <NUM>. The collar <NUM> comprises a groove <NUM> as positioning element. In particular the groove <NUM> of the collar need not to be closed on all three sides but can be also open at one side towards the inlet of the vacuum pump <NUM>. Thus, the groove can be built as abutment edge. The groove <NUM> of the collar <NUM> is engaged with one of the grooves 24a, 24b, 24c of the housing <NUM> by a snap ring <NUM> in order to define the axial position of the vacuum pump <NUM> with respect to the vacuum apparatus <NUM>. Assembling is performed by advancing the vacuum pump <NUM> into the collar <NUM> until the snap ring <NUM> abuts against the abutment edge <NUM>, <NUM> formed by the groove <NUM>.

As shown in <FIG>, the snap ring <NUM> is placed simultaneously in the groove <NUM> of the collar <NUM> and the groove 24a of the housing <NUM>.

If the collar <NUM> comprises more than one positioning element, as shown in <FIG>, then a first positioning element built by a first groove <NUM> has a first diameter and the second positioning element built by a second groove <NUM> has a second diameter. Therein, the first diameter is smaller than the second diameter. In particular, if more than two positioning elements are employed by the collar <NUM> then the diameter increases from one groove to the next in a direction from the second end <NUM> towards the first end <NUM>. Of course, also the positing elements in the housing <NUM> may have different diameters alternatively or additionally. Preferably, the snap ring <NUM> then might have a different thickness in the radial direction to compensate for the different diameters of the positioning elements. This may have the advantage that upon inserting the vacuum pump into the collar <NUM>, due to the decreasing diameter along the inserting direction, the respective snap ring <NUM> can be received by the respective groove <NUM>, <NUM> to attach the vacuum pump <NUM> to the collar <NUM>. Hereby in particular the groove <NUM>, <NUM> comprises an open side forming an abutment edge <NUM>, <NUM> facing against the inserting direction the snap ring <NUM> abuts against the abutment edge <NUM>, <NUM> formed by the respective groove <NUM>, <NUM> of the collar <NUM>.

Due to the collar <NUM> with the screws <NUM>, the vacuum pump <NUM> is fixed to the vacuum apparatus <NUM> wherein the axial position of the vacuum <NUM> with respect to the vacuum apparatus <NUM> is defined by the position of the respective grooves 24a, 24b, 24c and <NUM>. The centered position between the vacuum pump <NUM> and the vacuum apparatus <NUM> is maintained by the centering ring <NUM> as describe above. Further, between the housing <NUM> of the vacuum pump <NUM> and the vacuum apparatus <NUM> a vacuum tight seal <NUM> is arranged to seal and maintain the vacuum in the vacuum apparatus and the vacuum pump.

As shown, the housing <NUM> of the vacuum pump <NUM> comprises in the example of the figures three positioning elements built as grooves 24a, 24b, 24c. Thereby the number of the positioning elements and also the position of the positioning elements with respect to the housing <NUM> of the vacuum pump are not limited. Thus, a larger or smaller number of positioning elements can be employed and also the position of the positioning elements itself can be shifted along the axial axis of the vacuum pump <NUM> for example towards the second end <NUM>. However, if the groove <NUM> of the collar <NUM> is engaged with a groove 24a, 24b, 24c of the housing <NUM>, the axial position of the vacuum pump <NUM> with respect to different vacuum apparatus can be adapted providing a degree of freedom in design of the vacuum system. As shown in <FIG> protruding of the vacuum pump <NUM> from three exemplified vacuum apparatus <NUM>, as denoted by the lengths L1 to L3, can be adapted by using different positioning elements, i.e. grooves 24a, 24b, 24c of the housing <NUM>.

Claim 1:
Vacuum pump for connecting to a vacuum apparatus, comprising a housing (<NUM>) having a first end (<NUM>) defining an inlet (<NUM>) and a second end (<NUM>) opposite to the first end (<NUM>),
a collar (<NUM>) to be connected to a vacuum apparatus (<NUM>),
wherein the housing (<NUM>) and the collar (<NUM>) comprising each at least one positioning element (24a, 24b, 24c, <NUM>) for defining an axial position of the housing (<NUM>) relative to the collar (<NUM>),
characterized in that
the housing (<NUM>) and/or the collar (<NUM>) comprises more than one positioning element.