Improved gas deoiling element for rotary vane vacuum pump

Abstract

The invention relates to a gas deoiling element (1), in particular an air deoiling element, and to an oil separation and recovery device (3) comprising said element, for separating oil droplets from a gas, such as preferably air, in which a cross-sectional contraction, for example in the form of an orifice plate (2), is provided in the region where an oil-gas mixture enters the gas deoiling element. The invention also relates to: an oil-lubricated rotary vane vacuum pump (4) having a gas deoiling element (1) according to the invention, thereby increasing the service life of a sliding bearing; a method for operating an oil-lubricated rotary vane vacuum pump (4) according to the invention; a method of replacing the gas deoiling element (1) in such an oil-lubricated rotating vane vacuum pump (4); the invention relates to the use of a cross-sectional contraction, in particular an orifice plate, in a gas deoiling element according to the invention for increasing the service life of a sliding bearing of an oil-lubricated rotating vane vacuum pump; the invention further relates to the use of a gas deoiling element according to the invention in an oil-lubricated rotary vane vacuum pump for increasing the service life of a sliding bearing.

Description

[0001] The present invention relates to a gas oil separation element, in particular an air oil separation element, and to an oil separation and recovery device comprising such an element for separating oil droplets from a gas (such as, preferably, air) and being improved compared to devices in the prior art.

[0002] Separation devices of this type are used, for example, in vacuum pumps, in particular in oil-lubricated rotary vane pumps. Accordingly, the present invention also relates to an oil-lubricated rotary vane vacuum pump having a pump stage comprising a rotary vane chamber and a rotary vane rotor and having an oil separation and recovery device in which the separation of oil and gas (preferably oil and air) is carried out. TECHNICAL FIELD

[0003] Oil-lubricated rotary vane vacuum pumps are known. The pumps generally have a pump stage with a housing in which a cylindrical rotor is eccentrically arranged in a cylindrical rotary vane chamber. The cylinder and the cylinder head together form the rotary vane chamber housing into which the working medium flows and is then compressed and ejected. The axis of the eccentrically mounted rotor is parallel offset to the axis of the rotary vane chamber cylinder. The rotor has one or more vanes. The vanes are arranged such that they can move in a sliding manner in the slots of the rotor, where the slots are oriented in a substantially radial direction in cross-section. As the rotor rotates, the vanes are pressed against the inner wall delimiting the rotary vane chamber under the action of centrifugal force. During operation of the vacuum pump, the rotating rotor is radially displaced from the central axis of the cylindrical rotary vane chamber. This results in the formation of closed transfer chambers separated by radially movable vanes, the size of which changes during one revolution of the rotor. The change in the size of the transfer chambers during operation of the vacuum pump causes a pressure difference to occur between the individual transfer chambers, and it is in this way that the pressure difference between the intake side and the outlet side of the blower is formed.

[0004] An exemplary rotary vane vacuum pump has three vanes in three slots, defining three transfer chambers. Rotary vane vacuum pumps with more or fewer vanes, slots and transfer chambers are also conceivable. For example, a rotary vane vacuum pump with two vanes, slots and transfer chambers is also conceivable.

[0005] In an oil-lubricated rotary vane vacuum pump, oil is introduced into the pump stage or into the rotary vane chamber. By means of this oil, the gaps between the various components, in particular the gap between the vane and the wall of the rotary vane chamber, are blocked. Thus, the gas exchange between the individual transfer chambers is blocked. In this way, a higher vacuum can be obtained during operation than in a dry rotary vane vacuum pump. A rotary vane vacuum pump with a double pump stage can obtain a higher vacuum than a rotary vane vacuum pump with a single pump stage. The oil is also used to lubricate the rotor, which is rotatably arranged in a sliding bearing.

[0006] Due to design reasons, oil is transferred from the final chamber to the exhaust port together with the transfer gas. In addition, the oil is heated due to the compression enthalpy in the system. The oil may also be contaminated after contact with the pumping medium or may change due to possible chemical reactions. Therefore, it is preferred to treat the oil after it leaves the pump stage. In this regard, it is known to circulate the oil through the device.

[0007] In addition, it is known to perform the oil treatment process substantially in different sub-processes. For example, the oil and gas can first be separated in several stages, for example, by rough separation to separate large oil droplets, or further, for example, by gravity and / or impact. Another sub-process can be to filter the oil in a gas oil removal element including a filter element.

[0008] In addition, it is known to accommodate an oil separation device (preferably an oil separation device and a post-treatment device) in an oil separation and recovery housing, which is separated from the rotary vane housing but can be coupled to the rotary vane housing.

[0009] The gas oil removal element provided herein is accommodated in a replaceable manner in an oil separation and recovery housing adjacent to the rotary vane housing. The gas oil removal element is generally inserted into the oil separation and recovery housing by means of one or more positioning walls.

[0010] If an oil-lubricated rotary vane vacuum pump has not been used for a long time, the oil level is low at the start of the pump, and the sliding bearings are not sufficiently lubricated when the pump starts. This damages the surface of the sliding bearings and shortens their service life.

[0011] Therefore, the object of the present invention is to increase the service life of the sliding bearings of an oil-lubricated rotary vane vacuum pump. Prior Art

[0012] The above problems have not been disclosed or solved in the prior art. Oil-lubricated rotary vane vacuum pumps are known from, for example, WO2022 / 078591. Summary of the Invention

[0013] The object of the present invention is to further improve the rotary vane vacuum pump in the prior art, thereby increasing the service life of the sliding bearings.

[0014] The current solution involves narrowing the cross-section of the gas oil separation element on the intake side of the oil-gas mixture. In a conventional gas oil separation element, the cross-section is typically chosen such that the pressure loss on the intake side is as low as possible. In contrast, the cross-section of the gas oil separation element on the intake side of the oil-gas mixture is reduced. Preferably, the contracted diameter is 40% to 75% of the diameter of a conventional gas oil separation element without cross-section contraction, particularly preferably 45% to 70%, and very particularly preferably 50% of the diameter of a conventional gas oil separation element without cross-section contraction. Depending on the pump and the vacuum to be generated, the cross-section contraction can be adjusted accordingly.

[0015] According to the invention, this narrowing of the cross-section is preferably achieved by inserting an orifice plate into the gas oil separation element on the intake side of the oil-gas mixture. The orifice plate can be designed as an additional component and is preferably attached to the gas oil separation element by a positive fit. Force fit and material fit connections are also conceivable. The decisive factor is the pressure boost in the oil separation and recovery device. Alternatively, the intake part of the gas oil separation element can be selected to already have a cross-section contraction.

[0016] Using an orifice plate on the intake side of the oil-gas mixture facilitates the easy installation of the orifice plate, for example, the orifice plate can be snapped into place.

[0017] In a preferred embodiment, the gas oil separation element and the orifice plate are preferably designed as one piece.

[0018] The gas oil separation element according to the invention can also be easily replaced. For this purpose, in one embodiment according to the invention, the gas oil separation element is removed on the exhaust side of the oil-gas mixture. This is easily achievable because the gas oil separation element is preferably carried in a plug-in manner by one or more positioning walls in the oil separation and recovery device. Therefore, by simply unscrewing the exhaust hood, access to the gas oil separation element can be obtained, allowing it to be replaced.

[0019] Narrowing the cross-section by, for example, an orifice plate means that backpressure builds up faster because the pressure chamber becomes smaller. Due to this overpressure in the oil separation device, a high pressure gradient can be quickly generated compared to the pressure in the rotary vane chamber, which in turn causes the oil to flow quickly to the sliding bearing. In this way, lubricating oil can be supplied to the sliding bearing more quickly, minimizing the risk of bearing damage. This is particularly advantageous for oil-lubricated rotary vane vacuum pumps for generating a vacuum with a final pressure of up to 50 mbar, especially for those for generating a vacuum with a final pressure of up to 15 mbar.

[0020] Accordingly, the subject matter of the present invention is also the use of a cross-sectional constriction in a gas oil separation element according to the present invention for increasing the service life of the sliding bearings of an oil-lubricated rotary vane vacuum pump.

[0021] Another subject matter of the present invention is the use of an orifice plate in a gas oil separation element according to the present invention for increasing the service life of the sliding bearings of an oil-lubricated rotary vane vacuum pump.

[0022] Likewise, the subject matter of the present invention is the use of a gas oil separation element according to the present invention in an oil-lubricated rotary vane vacuum pump for increasing the service life of the sliding bearings.

[0023] Filtration of the oil is carried out in the gas oil separation element: an oil-containing gas stream circulates from the inlet of the housing in which the gas oil separation element is installed to the outlet, after which an oil-free gas stream leaves from the said outlet. The gas oil separation element often has the form of a cylindrical barrel and is usually provided with an inlet part and a closing cover such that the gas stream passes through a cylindrical filter wall before being directed to an exhaust hood. In a preferred embodiment, the inlet part, the cylindrical filter element and the closing cover are non-detachably connected to each other, in particular glued together.

[0024] That is to say, the flow direction of the oil can be given by the longitudinal extension of the oil separation and recovery housing or by the correspondingly gas oil separation element. This is the basic flow direction from the region at one end of the housing along its longitudinal extension to the region at the other end of the housing, and thus a deviation from the direction of strictly linear flow can be provided in this flow from one end of the housing to the other end. Due to the strong change in velocity, the cross-sectional constriction causes additional pre-separation of the oil.

[0025] Accordingly, the subject matter of the present invention is also an improved oil separation and recovery device, which comprises a gas oil separation element according to the present invention.

[0026] From the following description of the preferred embodiments of the present invention, more details of the present invention will become apparent, wherein the preferred embodiments are shown in the drawings. More advantages of the present invention can also be learned from the description, as well as suggestions and proposals on how to modify and even further develop the subject matter of the present invention within the claimed scope.

[0027] The entire specification, claims and drawings also disclose the inventive features in specific embodiments and combinations. Those skilled in the art can also independently consider these features and combine them into further combinations or sub-combinations, so that the invention defined in the claims can be adapted to his or her needs or to a specific application field. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 A cross-sectional schematic view showing the state of the pump with an oil supply and a sliding bearing arrangement is shown.

[0030] Figure 2A A perspective view of an oil-lubricated rotary vane vacuum pump is shown.

[0031] Figure 2B Shown is a top view of an oil-lubricated rotary vane vacuum pump according to Figure 2A ...

[0032] Figure 3 A partial cross-sectional view of an oil-lubricated rotary vane vacuum pump is shown, focusing on the oil separation and recovery device.

[0033] Figure 4 A transverse cross-sectional view of the oil separation and recovery device according to the present invention is shown.

[0034] Figure 5A A cross-sectional view of a gas deoiling element with an inserted orifice plate is shown.

[0035] Figure 5B A perspective view of a gas deoiling element with an inserted orifice plate is shown. Detailed Description of the Invention

[0036] From Figure 1 In the cross-sectional view of the pump stage with the oil supply and sliding bearing arrangement shown therein, the situation of supplying oil to the sliding bearing 23 in the oil-lubricated rotary vane vacuum pump can be seen. 00 represents the oil level at pump startup, and 01 is the oil level during the operation of the motor 12: this means that the sliding bearing is not lubricated with oil at pump startup. Therefore, in order to prevent the pump from "seizing", it is necessary to quickly lubricate the sliding bearing 23 with oil as in the case of pump operation. This rapid lubrication of the sliding bearing 23 is achieved by narrowing the cross-section of the gas deoiling element on the intake side of the oil-gas mixture, because the greater the pressure difference between the pump stage 5 and the oil separation and recovery device 3, the faster the oil supply to the sliding bearing. Therefore, the sliding bearing 23 can be fully lubricated in a rapid manner, thereby increasing its service life.

[0037] Figure 1 The arrows in... indicate the oil flow in the pump stage during pump startup and operation.

[0038] Figure 1 Also shown is the cylindrical rotary vane rotor 9 in the rotary vane chamber 8, and the motor 12.

[0039] Figure 2A A perspective view of the oil-lubricated rotary vane vacuum pump 4 according to the present invention is shown, wherein the oil-lubricated rotary vane vacuum pump 4 is provided with a motor 12 and an oil separation and recovery device 3. The exhaust hood 7 can also be seen.

[0040] Figure 2B Shown is Figure 2ATop view of the oil-lubricated rotary vane vacuum pump 4 according to the invention, where the oil-lubricated rotary vane vacuum pump 4 has a pump stage 5, an electric motor 12, and an oil separation and recovery device 3. It can be clearly seen that the orifice plate 2 is inserted into the gas deoiling element 1 on the intake side of the oil-gas mixture. The gas deoiling element 1 preferably includes a filter element 29, a closure cap 27, and an intake member 28, and these three parts can be inseparably connected to each other. In particular, these three parts (27, 28, and 29) are adhesively bonded to each other. The exhaust hood 7 can also be seen, and the gas after cleaning can escape through the exhaust hood 7.

[0041] Figure 3 A partial cross-sectional view of the oil-lubricated rotary vane vacuum pump 4 according to the invention is shown, focusing on the oil separation and recovery device 3 and its housing 14. The housing 14 includes a top wall 16, a bottom wall 17, and side walls 15 and 26. The gas deoiling element 1 can be replaced through an opening 6, where the opening 6 is formed by removing the exhaust cover 7. Here, the gas deoiling element 1 including the orifice plate 2, the intake member 28, the filter element 29, and the closure cap 27 is preferably inserted into the oil separation and recovery device 3 by means of a plurality of positioning walls 19.

[0042] The oil, together with the pumped gas, is transferred from the final transfer chamber of the pumping stage 5 to the exhaust port. In addition, due to the compression enthalpy in the system, the oil will be heated. When the oil comes into contact with the pumped medium, the oil will also be contaminated or changed due to possible chemical reactions. Therefore, it is preferable to treat the oil after it leaves the vacuum area. In this regard, it is known to circulate the oil through the device. From Figure 3 It can be seen that the oil-gas mixture regularly passes through the gas deoiling element 1, where the gas deoiling element 1 has a cross-sectional contraction preferably in the form of an orifice plate 2 in the intake area. During pump operation, the unfilled arrows indicate the gas flow, and the filled arrows indicate the oil flow.

[0043] The oil separation and recovery device can preferably have a chamber formed integrally. Referring to the installation conditions also shown in the drawings, the lower chamber 20 and the upper chamber 21 are formed under gravity. The separation of the chambers 20 and 21 is achieved by a partition bottom plate 22 that extends laterally to the side walls 15 and 26, and its cross-section refers to Figure 3 .

[0044] The upper chamber 21 is mainly used to accommodate the gas deoiling element 1. It preferably extends in a direction substantially the same as the rotor axis. In the longitudinal direction of the upper chamber 21, its ends are defined by the retaining walls 19.

[0045] During the operation of the rotary vane vacuum pump 4, the oil-gas mixture enters the oil separation and recovery device 3 from the pump stage 5 through the channel opening 24 in the area of the outer wall 18 (refer to Figure 4)。Therefore, the channel opening 24 is the air inlet of the oil separation and recovery device.

[0046] First, the rough separation of large oil droplets can be performed by gravity and / or an impact separator. In the housing 14 of the oil separation and recovery device, the housing portion 25 below the channel opening 24 can function like an oil pan in an oil sump. Therefore, Figure 3 The possible oil level 30 is also shown. An oil storage area can thus be formed in the lower chamber 20.

[0047] In addition, the lower chamber 20 forms a flow channel in the longitudinal direction of the housing 14. This flow is directed generally in the direction of the side wall 26, and the flow deflects in the region of the side wall 26 to enter the upper chamber 21.

[0048] The gas deoiling element 1 accommodated in the upper chamber 21 often has a filter element 29, especially a filter element in the form of a fine separation device, for example.

[0049] The oil-gas mixture diverted from the lower chamber 20 to the upper chamber 21 is directed to pass through the gas deoiling element 1 in a targeted manner, so that a pressure difference is generated between the upstream and downstream of the gas deoiling element 1. Depending on the transfer pressure of the pump stage 5 and the type of pump, this pressure difference can be up to 800 mbar when the pump is started.

[0050] As shown by the arrow, the gas deoiling element 1 has a generally centered axial flow, and the cleaned gas can leave the housing 14 of the oil separation and recovery device through the exhaust cover 7. The oil droplets are thus separated in the gas deoiling element 1 and then returned to the oil sump as described above.

[0051] Figure 4 A transverse cross-section of the oil separation and recovery device according to the present invention is shown. In particular, the orifice plate 2 of the gas deoiling element and the plug-in holding device by means of the holding wall 19 can be seen; in addition, the individual parts of the housing 14 of the oil separation and recovery device can also be seen: the side wall 15, the top wall 16, the bottom wall 17, and the outer wall 18. In addition, the lower chamber 20, the channel opening 24, the housing portion 25, the upper chamber 21, and the partition bottom plate 22, as well as the oil level 30, can also be seen.

[0052] Figure 5A A cross-section of the gas deoiling element 1 according to the present invention is shown, with the inserted orifice plate 2, the inlet member 28, and the filter element 29. The orifice plate 2 is preferably located on the air inlet side where the oil-gas mixture enters the oil separation and recovery device. As shown, the orifice plate 2 can be designed as an additional component and is preferably attached to the gas deoiling element 1 by means of a positive fit. Force-locking connections and material-locking connections are also conceivable. The decisive factor is the pressure boost in the oil separation and recovery device. Alternatively, the inlet member 28 of the gas deoiling element can be selected such that it already has a cross-sectional contraction.

[0053] Figure 5B Figure 2 shows a perspective view of a gas deoiling element 1 according to the present invention, with an intake member 28, a filter element 29, and an insertable orifice plate 2, which is preferably located on the intake side where the oil-gas mixture enters the oil separation and recovery device.

[0054] In summary, it should be pointed out again that the exemplary embodiments described herein only represent possible modes that can implement the inventive concept, and they should not be regarded as restrictive. Those skilled in the art will understand that there can be other embodiments of the present invention and other elements without neglecting the basic features of the present invention.

[0055] List of Reference Numerals

[0056] 00 Pump start oil level

[0057] 01 Oil level during motor operation

[0058] 1 Gas deoiling element

[0059] 2 Orifice plate

[0060] 3 Oil separation and recovery device

[0061] 4 Oil-lubricated rotary vane vacuum pump

[0062] 5 Pump stage

[0063] 6 Opening

[0064] 7 Exhaust hood

[0065] 8 Rotary vane chamber

[0066] 9 Rotary vane rotor

[0067] 12 Motor

[0068] 13 Transfer chamber

[0069] 14 Oil separation and recovery device housing

[0070] 15 Side wall

[0071] 16 Top wall

[0072] 17 Bottom wall

[0073] 18 Outer wall

[0074] 19 Retaining wall

[0075] 20 Lower chamber

[0076] 21 Upper chamber

[0077] 22 Partition bottom plate

[0078] 23 Sliding bearing

[0079] 24 Channel opening

[0080] 25 Housing part

[0081] 26 Side wall

[0082] 27 Sealing cover

[0083] 28 Intake part

[0084] 29 Filter element

[0085] 30 Oil level

Claims

1. Gas oil separation element (1), characterized in that, There is a cross-sectional contraction in the area where the oil-gas mixture enters the gas oil removal element.

2. The gas oil separation element (1) according to claim 1, characterized in that, The cross-sectional contraction is achieved by means of an orifice plate (2) which is located in the area where the oil-gas mixture enters the gas oil removal element.

3. The gas oil separation element according to claim 1 and / or 2, characterized in that, The cross-sectional contraction preferably reduces the diameter of the gas oil removal element to 40% to 75% of the initial value, particularly preferably to 45% to 70% of the initial value, and very particularly preferably to 50% of the initial value.

4. The gas oil separation element according to one or more of claims 1 to 3, characterized in that, The gas oil removal element and the orifice plate are integrally formed.

5. An oil separation and recovery device (3) for separating oil droplets from a gas, comprising a gas oil separation element (1), characterized in that, The gas oil removal element is the gas oil removal element according to one or more of claims 1 to 4.

6. An oil-lubricated rotary vane vacuum pump (4) with a pump stage (5) and an oil separation and recovery device (3), the pump stage (5) comprising a rotary vane chamber (8) and a rotary vane rotor (9) in a sliding bearing (23), wherein in the oil separation and recovery device (3) the separation of gas and oil, in particular air and oil, is preferably carried out by means of the gas oil separation element (1), characterized in that, The gas oil removal element (1) is the gas oil removal element according to one or more of claims 1 to 4.

7. The oil-lubricated rotary vane vacuum pump (4) according to claim 6, characterized in that, The ultimate pressure of vacuum generated by the oil-lubricated rotary vane vacuum pump (4) is in the range up to 50 mbar, in particular the ultimate pressure is in the range up to 15 mbar.

8. A method of operating an oil-lubricated rotary vane vacuum pump (4) according to claim 6 and / or 7.

9. A method of replacing the gas oil separation element (1) according to one or more of claims 1 to 4 in an oil-lubricated rotary vane vacuum pump (4).

10. Use of a cross-sectional contraction in the gas oil separation element (1) according to one or more of claims 1 to 4 for increasing the service life of the sliding bearing (23) of an oil-lubricated rotary vane vacuum pump (4).

11. Use of an orifice plate (2) in the gas oil separation element (1) according to one or more of claims 2 to 4 for increasing the service life of the sliding bearing (23) of an oil-lubricated rotary vane vacuum pump (4).

12. Use of the gas oil separation element (1) according to one or more of claims 1 to 4 in an oil-lubricated rotary vane vacuum pump (4) for increasing the service life of the sliding bearing (23).

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