EP3636879B1 - Vacuum pump - Google Patents

Description

The present invention relates to a vacuum pump comprising: a pump chamber in which a gas to be conveyed can be conveyed from an inlet to an outlet by means of a pump body; a first channel, which opens into the pump chamber, for feeding a ballast gas into the pump chamber, and a second channel, which discharges into the pump chamber, for feeding a further gas, in particular different from the gas to be pumped, into the pump chamber. Such vacuum pumps are about in US 2005/0163632 A1 and the EP3 483 448 A1 disclosed.

In common, in particular single-stage, rotary vane pumps, a noise dampening device is provided through which air at atmospheric pressure is guided to the pump chamber of the pump via a channel containing a constriction, in particular a nozzle, for volume flow regulation. Another channel also leads air or gas as gas ballast, e.g. to increase the water vapor capacity, into the pump room.

It is an object of the invention to simplify the production of a vacuum pump of the type mentioned at the beginning.

This object is achieved by a vacuum pump with the features according to claim 1, and in particular in that the channels have a common opening into the pump chamber.

Only one mouth has to be made, which saves drilling operations. This simplifies production and makes it more cost-effective.

In addition, it has surprisingly been shown that the pump according to the invention works more quietly in certain operating states. This is explained by the fact that the ballast gas can escape through the second channel if the pressure of the ballast gas is too high. This prevents undesired overpressure in the pump chamber.

According to one embodiment it is provided that the channels have a common channel section. This further simplifies production, since further drilling operations can be saved.

The common channel section can, for example, comprise an orifice channel section which is arranged, for example, transversely, in particular perpendicularly, to at least one separate channel section of one of the channels and / or to another section of the common channel section, in particular a longer section or a main section. The mouth channel section can be defined, for example, by a bore, in particular the other section of the common channel section being defined by a bore running transversely to this bore. The mouth channel section can generally run, for example, at least substantially parallel to an axis of rotation of the pump body.

In a further embodiment with particularly simple manufacture, it is provided that a separate channel section of at least one of the channels and the common channel section each run at least partially at least essentially in one plane. In general, both channels can have their own channel section, in particular with their own channel sections at least partially running at least essentially in one plane. Both the own channel sections and the common channel section preferably run at least partially at least essentially in one plane. Generally preferred, the channel sections in each of the combinations shown, in particular, at least insofar as they are defined in a common component, run completely in one plane.

At least one channel section, in particular at least one separate channel section and / or a common channel section, can preferably run transversely, in particular perpendicularly, to a rotor axis of the pump body. This represents a particularly space-saving solution in terms of installation space.

In principle, the first channel and / or the second channel can be defined at least in sections by a bore.

In a further development, a separate channel section of one of the channels is defined by a bore. In particular, the common channel section can also be at least partially defined by this bore. This can further simplify production. Preferably, the first channel can be defined by the bore that defines the common channel section.

A separate channel section of the other channel can open into the bore, for example, in particular into the one that defines the common channel section. Here or in principle, i.e. independently of the above embodiment, the own channel section of the other channel itself can be defined by a bore which, for example, runs transversely to the bore of the common channel section.

According to an advantageous example, the common mouth can be defined in a structural component, a housing component, a component that carries a bearing element for the pump body, and / or in a component that axially and / or radially delimits the pump chamber in relation to an axis of rotation of the pump body. In principle, the component in which the mouth is defined can also meet several or all of these characteristics. For example, the component can be a so-called end shield.

In some embodiments, it is provided that at least one channel section defines in a structural component, a housing component, a component that carries a bearing element for the pump body, and / or in a component that axially and / or radially delimits the pump chamber in relation to an axis of rotation of the pump body is. In particular, a separate channel section of the first channel, a separate channel section of the second channel and / or a common channel section can be defined in the component.

In principle, it can be advantageous if separate channel sections of the two channels are defined in the same component. This represents a simple solution in terms of production technology. A common channel section can preferably also be defined in this component. This simplifies the manufacturing process even further.

For example, at least one of the channels, in particular in or on its own channel section, can have a valve for controlling the gas inlet into the channel. For example, a gas ballast valve can be provided for the first channel.

In principle, the second channel can preferably be provided for admitting the further gas for the purpose of noise damping. The further gas can be air, for example, in particular ambient air and / or atmospheric pressure.

According to a further development it is provided that at least one of the channels, in particular the second channel, a constriction and / or a nozzle is provided on or in its own channel section. Thus, the amount of the relevant, in particular second, channel supplied gas can be regulated in a simple manner.

The vacuum pump can be, for example, a rotary displacement vacuum pump. The vacuum pump is particularly preferably a rotary vane vacuum pump, preferably an oil-lubricated rotary vane vacuum pump. In particular, the pump body can be formed by a rotor shaft and in particular at least one rotary slide valve. The vacuum pump can be single-stage or multi-stage, for example two-stage.

For example, an inert gas or, for example, air can be provided as ballast gas. During operation it is necessary under certain circumstances to introduce additional gas, here generally referred to as ballast gas, as drag gas, flushing gas or sealing gas into the pump chamber. For example, when corrosive gases are conveyed, ballast gas in the form of an inert sealing gas is introduced into the pump chamber in order to protect sensitive components of the vacuum pump. The ballast gas can also be used for cooling, for example when the vacuum pump is heated up due to a shift in the operating point. So-called drag gas is introduced in order to be able to pump particularly light gases such as hydrogen or helium better. Towing gas can also be used to transport undesired accumulations, e.g. condensation of liquid substances or deposits of solid substances within the pump system in the direction of an outlet of the vacuum pump. After the vacuum pump has been switched off, ballast gas can be introduced as flushing gas in order to prevent condensation of, in particular corrosive, gases in the pump chamber. A suitable ballast gas for this application is nitrogen, for example.

Further areas of application concern the dilution of a pumped gaseous medium ("passive addition"), for example to achieve an ignitable gas concentration to avoid, which can result from a compression of the medium during the pumping process in different places in the pumping system. In contrast, when "active addition" is used, the pumped medium is changed to a more harmless type, in which case, for example, by adding suitable reactants or catalysts, corrosive or otherwise harmful components of the pumped medium can be precipitated and removed.

The supply of ballast gas into the pump chamber is controlled, for example, by a valve whose inlet opening is connected to a ballast gas container by means of a connecting hose and whose outlet opening is connected to the pump chamber.

The common orifice is preferably arranged in a region of the pump chamber in which a higher pressure prevails during operation than at the inlet. In particular, the common orifice can be arranged in an area of the pump chamber with a pressure between 50 and 300 mbar during operation.

The invention basically also relates to a system comprising a vacuum pump according to the type described above, a ballast gas supply device being connected to the first channel and an air inlet being provided or connected to the second channel. This system is disclosed here, for example, for the purpose of a later claim. It goes without saying that the system can advantageously be developed further in the sense of the features and embodiments described here with regard to the vacuum pump.

Fig. 1

zeigt eine beispielhafte Vakuumpumpe.

Fig. 2

zeigt die Vakuumpumpe der Fig. 1 in einer Schnittansicht.

Fig. 3

zeigt die Vakuumpumpe der Fig. 1 in einer weiteren Schnittansicht.

Fig. 4

zeigt die Vakuumpumpe der Fig. 1 in einer weiteren Schnittansicht.

The invention is explained below by way of example only with reference to the schematic drawing.

Fig. 1

shows an exemplary vacuum pump.

Fig. 2

shows the vacuum pump of the Fig. 1 in a sectional view.

Fig. 3

shows the vacuum pump of the Fig. 1 in a further sectional view.

Fig. 4

shows the vacuum pump of the Fig. 1 in a further sectional view.

In Fig. 1 a vacuum pump 10 is shown in a side view. The vacuum pump 10 is designed as a rotary vane vacuum pump and is set up to convey a gas to be conveyed from an inlet 12 to an in Fig. 1 to promote outlet not shown.

The vacuum pump 10 comprises a housing component 14 in which the pump-active components of the pump are accommodated. This is in Fig. 2 which shows a sectional view of the vacuum pump 10 with a sectional plane in the region of the inlet 12. In particular, a rotor shaft 16 with rotary slides 18 mounted displaceably on the rotor shaft 16, which are provided for rotation in a pump chamber 20 and which convey the gas to be conveyed from the inlet 12 to an outlet 22 when the rotor shaft 16 rotates, is arranged in the housing component 14. The subsection of the rotor shaft 16 arranged in the pump chamber 20 forms, together with the rotary valves 18, a pump body of the pump 10.

In Fig. 3 the vacuum pump 10 is shown in a sectional view, the sectional plane in FIG Fig. 1 indicated by the line AA. In particular, the rotor shaft 16 can be seen as it is supported in the housing component 14. The sectional plane runs through a wall 21 of the housing component 14 which axially delimits the pump chamber 20, which is why the pump chamber 20 is not visible here. The rotor shaft 16 is mounted on this wall 21 by means of a bearing element 23, here a plain bearing.

The vacuum pump 10 comprises a gas ballast valve 24, which is provided for connection to a ballast gas supply device (not shown), for example a ballast gas container. In addition, the vacuum pump 10 comprises a connection 26 for admitting air, preferably for the purpose of noise damping. Both the ballast gas and the air for noise damping are fed to the pump chamber 20.

For this purpose, a first and a second channel are provided, namely each from the gas ballast valve 24 and from the connection 26 to the pump chamber 20. The channels have a common opening 28 into the pump chamber 20.

The first channel runs from the gas ballast valve 24 to the orifice 28 and comprises its own channel section 30 and a common channel section 32. The second channel runs from the connection 26 to the orifice 28 and includes its own channel section 34 and the common channel section 32.

In this embodiment, all channel sections are designed as bores which are introduced into the housing component 14 or into the wall 21 axially delimiting the pump chamber 20. The own channel section 30 of the first channel and the common channel section 32 are formed here by the same bore, a first longitudinal section of the bore forming the channel section 30 and a second longitudinal section of the bore forming the channel section 32. The own channel section 34 of the second channel is designed as a further bore which runs transversely to the first bore and opens into it. In this example, the two bores lie in a plane which runs perpendicular to the axis of rotation of the rotor shaft 16.

the Fig. 4 FIG. 10 shows a further sectional view of the vacuum pump 10 of FIG Fig. 1 , the cutting plane along an in Fig. 1 indicated line BB runs. In particular, a cross section of the common channel section 32 and the common opening 28 into the pump chamber 20 is visible. The mouth 28 is connected to the common channel section 32 via a mouth channel section 36, which is also designed as a bore. The mouth channel section 36 runs transversely to the common channel section 32 and here in particular parallel to the rotor shaft 16.

How it looks in particular Fig. 4 As can be seen, the wall 21 axially delimiting the pump chamber 20 is formed in one piece with the housing component 14. Alternatively, a separate design would also be possible, for example.

In the embodiment shown, the common opening 28 and the own and common channel sections 30, 32, 34 are consequently defined in a component which axially delimits the pump chamber 20, namely in the housing component 14. Alternatively or additionally, a position of the opening in a radial direction would also be, for example Arrangement is conceivable, in particular in the cylinder wall of the housing part 14 which radially delimits the pump chamber 20. The position and shape of the channel sections 32 and 36 and the opening 28 could be different from what is shown. The mouth would then not run parallel to the axis of rotation and / or not axially to the channel section 36, but in particular at right angles to the axis of rotation and / or at a suitable angle to the channel section 36.

The solution shown ultimately integrates the duct routing and spraying of the noise dampening in the gas ballast duct (or vice versa). This means that fewer holes have to be provided on the pump. The pump becomes more compact and cheaper to manufacture. In contrast to other pumps of a similar design, which have a higher noise level when the gas ballast is open, in the described invention the noise level can even decrease when the gas ballast is open.

In principle, the pump 10 shown in the figures can also comprise further channel sections, for example for similar or different purposes, which can be formed, for example, in the housing component 14 and / or other housing components. In particular, the pump 10 on which the drawings are based has further channel sections which are hidden in the figures for the sake of clarity.

List of reference symbols

10

Vacuum pump

12th

inlet

14th

Housing component

16

Rotor shaft

18th

Rotary valve

20th

Pumping room

21

Wall

22nd

Outlet

23

Bearing element

24

Gas ballast valve

26th

connection

28

mouth

30th

own canal section

32

common channel section

34

own canal section

36

Mouth channel section

Claims (15)

1. A vacuum pump (10) comprising:

   a pump space (20) in which a gas to be conveyed can be conveyed from an inlet (12) to an outlet (22) by means of a pump body (16, 18);

   a first channel (30, 32), which opens into the pump space (20), for feeding a ballast gas into the pump space (20);

   a second channel (34, 32), which opens into the pump space (20), for feeding a further gas into the pump space (20);

   characterized in that

   the channels have a common opening (28) into the pump space (20).
2. A vacuum pump (10) in accordance with claim 1,
   wherein the channels have a common channel section (32).
3. A vacuum pump (10) in accordance with claim 1 or claim 2,
   wherein a separate channel section (30, 34) of at least one of the channels and the common channel section (32) each at least partly extend at least substantially in one plane.
4. A vacuum pump (10) in accordance with at least one of the preceding claims,
   wherein at least one channel section (30, 32, 34) extends transversely to an axis of rotation of the pump body (16).
5. A vacuum pump (10) in accordance with at least one of the preceding claims,
   wherein a separate channel section (30) of one of the channels is defined by a bore and the common channel section (32) is likewise defined by this bore.
6. A vacuum pump (10) in accordance with claim 5,
   wherein the first channel (30, 32) is defined by the bore.
7. A vacuum pump (10) in accordance with claim 5 or claim 6,
   wherein a separate channel section (34) of the other channel opens into the bore.
8. A vacuum pump (10) in accordance with at least one of the preceding claims,
   wherein the common opening (28) is defined in a structural component (14), a housing component (14), a component (14) which supports a bearing element (23) for the pump body (16, 18), and/or in a component (14) which axially and/or radially bounds the pump space (20) with respect to an axis of rotation of the pump body (16, 18).
9. A vacuum pump (10) in accordance with at least one of the preceding claims,
   wherein at least one channel section (30, 32, 34, 36) is defined in a structural component (14), a housing component (14), a component (14) which supports a bearing element (23) for the pump body (16, 18), and/or in a component (14) which axially and/or radially bounds the pump space (20) with respect to an axis of rotation of the pump body (16, 18).
10. A vacuum pump (10) in accordance with at least one of the preceding claims,
    wherein separate channel sections (30, 34) of the two channels are defined in the same component (14).
11. A vacuum pump (10) in accordance with claim 10,
    wherein a common channel section (32) is also defined in this component (14).
12. A vacuum pump (10) in accordance with at least one of the preceding claims,
    wherein at least one of the channels has a valve for controlling the admission of gas into the channel.
13. A vacuum pump (10) in accordance with at least one of the preceding claims,
    wherein the second channel is provided for admitting the further gas for the purpose of noise damping.
14. A vacuum pump (10) in accordance with at least one of the preceding claims,
    wherein a nozzle is provided at or in the separate channel section (34) of the second channel.
15. A vacuum pump (10) in accordance with at least one of the preceding claims,
    the vacuum pump (10) is a rotary vane pump.

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