Filter system

Abstract

SOLUTION: To provide a filter system for a vacuum pump, in particular for an oil sealing type vacuum pump which includes a filter element (10), wherein the filter element (10) is arranged in a filter housing (12), a filter inlet element (14) is stored in a housing inlet (16), the filter element (10) has a wing-shaped tab (54) in particular in a region of a filter outlet element (24), and the tab cooperates with a corresponding slot-shaped receiving element (58) provided in the filter housing (12); and in order to improve adjustment of the filter element (10) at a prescribed position in the filter housing (12), the filter inlet element (14) and the housing inlet (16) and / or a holding element (54) and a receiving element (58) are correspondingly formed.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a filter system for a vacuum pump. In particular, the filter system is a filter system for an oil-sealed vacuum pump and is particularly suitable for rotary vane pumps.

Summary of the Invention

Problems to be Solved by the Invention

[0002] When using a rotary vane pump and possibly other oil vacuum pumps, it is necessary to filter the mixture of lubricant and gas, which is an oil-air mixture generated especially when sending gaseous media. An appropriate filter system is used to return the lubricant to the lubrication system and release the remaining clean gas. It is necessary to regularly replace the filter element of such a filter system. In known filter systems, replacing the filter element is complicated. In particular, it is often necessary to disassemble several parts connected to the filter element. Therefore, these parts need to be refitted and attached to a new filter again. Such work is complicated on the one hand and often gets dirty because the parts covered with lubricant have to be disassembled.

[0003] Furthermore, the problem often occurs that the filter may be installed in a wrong position. For this reason, the filtration performance may be impaired or the filtration effect may be completely eliminated.

[0004] An object of the present invention is to provide a filter system for a vacuum pump, especially an oil-sealed vacuum pump, in which the replacement of the filter element is simple. A further object of the present invention is to provide a method for providing such a filter system for a vacuum pump and a method for replacing the filter element of such a filter system.

Means for Solving the Problems

[0005] These objectives are addressed by the filter system of claim 1 and the methods of claims 13 and 16, according to the present invention.

[0006] A filter system particularly suitable for vacuum pumps, and especially preferably for oil-filled vacuum pumps such as rotary-blade pumps, comprises a filter element housed within a filter housing. The filter element serves to filter out lubricants, such as oil, from a lubricant-gas mixture, particularly a mixture of lubricant and air. The filter element has a filter inlet element, through which the lubricant-gas mixture flows into the filter element. During operation, when the filter element is installed within the filter housing, the filter inlet element is housed in the housing inlet of the filter housing. Furthermore, the filter element has a retaining element, particularly in the area of ​​the filter outlet element, i.e., the area from which the gas flows out of the filter element. When the filter element is installed, the retaining element cooperates with a receiving element provided in the filter housing. Since the filter element generally has a cylindrical or conical shape, it is preferable that the base of the cylindrical or conical shape be, for example, circular, oval, rectangular, elliptical, or polygonal. Furthermore, it is preferable that the filter outlet element and / or filter inlet element are located at the axial ends of the filter element. In a particularly preferred embodiment, the filter outlet element is located at one axial end of the filter element, and the filter inlet element is located at the other axial end of the filter element. It is preferable that the filter housing has a substantially hollow cylindrical or hollow conical shape. Here again, the base of the hollow cylindrical or hollow conical can be associated with, for example, a circular, oval, rectangular, elliptical, or polygonal shape.

[0007] To ensure the defined position and, consequently, reliable adjustment of the filter element within the filter housing, the filter inlet element and housing inlet of the first preferred embodiment are configured such that the filter inlet element can be received by the housing inlet in only one position for adjustment. In alternative embodiments, the retaining element of the filter element and the receiving element of the filter housing are configured such that the retaining element can be received by the receiving element in only one position for adjustment. In preferred embodiments, these two possibilities are combined for specific adjustments. By making at least one such adjustment, it is ensured that the filter element can be positioned within the filter housing in only one defined position. Such a guarantee is particularly important when the filter element has, for example, various filter regions, and the position of the filter regions is important for the filter element to function reliably. For example, the filter element may further have a drip edge that needs to face downward when installed.

[0008] In preferred embodiments, the filter inlet elements and housing inlet, preferably configured to be complementary to each other, are configured to have a non-circular cross-section. For example, a cross-section having a flat portion, a recessed portion, or a raised portion in part of a circular cross-section. Thus, the filter elements of the corresponding configurations can be inserted into the housing inlet only at a predetermined position. For this purpose, one of the two parts can be provided with, for example, a tab, particularly a radially positioned tab or projection. Thus, the tab engages with the corresponding recess. In particular, if the filter inlet element has a tab that protrudes radially outward, the filter element may have a circular opening in cross-section, so that the flow is not impaired by an open cross-section.

[0009] In a particularly preferred embodiment, the retaining element has at least one, and more particularly two, wing-shaped tabs. When installed, these tabs are inserted into slot-shaped recesses of the receiving element of the filter housing. The wing-shaped tabs may here again serve to adjust to only one appropriate position, but may have the further advantage of being able to properly grip and, consequently, handle the filter element. Insertion of the filter element into the filter housing can be achieved by gripping the filter element with two, preferably wing-shaped tabs. In a particularly preferred embodiment, the wing-shaped tabs are not positioned opposite each other, i.e., not at a 180° angle to each other, so that the filter element can be inserted only in a predetermined position, depending on the angle between the two wing-shaped tabs. Similarly, the wing-shaped tabs themselves have tabs, projections, grooves, etc., that cooperate with correspondingly matching projections and recesses of the receiving element, so that their position is similarly determined.

[0010] It is preferable that the filter system for a vacuum pump is constructed such that insertion of the filter element into the housing is achieved by axial insertion into the housing, taking the filter element into consideration. In other words, the filter system for a vacuum pump is configured such that the filter element can be inserted into the housing by axial, preferably sliding, movement. Since this insertion is achieved by axial insertion of the filter element into the housing, it is preferable that the filter element and the housing are axially aligned with each other, for example, when the housing and the filter element have a conical and / or cylindrical shape. It is preferable that the connection and / or sealing of the filter inlet element and the housing inlet is achieved by the axial contact pressure of the filter element against the housing. Therefore, for example, radial movement and / or screwing of the filter element relative to the housing is not required.

[0011] In a more preferred embodiment, the filter inlet element has an annular shoulder in cross-section to receive a particularly annular sealing element, such as an O-ring. Therefore, conventional sealing elements can be used, as the sealing element does not necessarily need to fit into a non-circular filter inlet element in some cases.

[0012] In another preferred embodiment, the filter system includes a tension element. The tension element may be a spring, and more particularly, a coil spring. The tension element is preferably located in the region of the filter outlet element where the filtered gas flows out of the filter element. By providing such a tension element, it is possible to apply a holding force to the installed filter element, or while the filter element is installed. Thus, here again, the position of the filter element within the filter housing is more effectively and uniquely determined. Specifically, the tension element can apply a compressive force to the sealing element, thereby ensuring a secure seal.

[0013] It is even more preferable that the filter housing has an insertion opening for inserting a filter element. The insertion opening is preferably closed by a housing cover. In a particularly preferred development of the present invention, the housing cover is fixed to the filter housing by fixing elements, particularly a plurality of screws. Here, it is preferable that fixing the housing cover generates tension in the tension element, i.e., a holding force by the tension element. For example, the housing cover is pulled towards the outer wall of the filter housing by fixing elements such as a plurality of screws. Here, the tension element is indirectly or directly supported on the inner surface of the housing cover and is then compressed, for example, by tightening screws or by providing the fixing elements.

[0014] The filter element is preferably substantially cylindrical in cross-section, with a drip edge provided on the outer bottom surface of the filter element, and particularly preferably extending along the entire length of the filter element. The drip edge must face downward when installed. If a substantially cylindrical filter element is used, it is even more preferable that the filter inlet element is positioned substantially opposite the filter outlet element.

[0015] It is preferable that the pressure relief valve is provided in the flow direction, particularly upstream of the filter outlet element. The pressure relief valve serves to prevent excessive pressure from accumulating in the filter element, for example, if the filter element becomes clogged.

[0016] In a more particularly preferred embodiment, the filter housing has at least one guide element on its inner surface facing the filter element. The guide element is provided particularly in the area of ​​the housing inlet. The guide element serves to adjust the filter inlet element when it is inserted into the filter housing, so that the filter inlet element can be easily inserted into the housing inlet. It is particularly preferred that there are two guide elements extending longitudinally, i.e., in the direction in which the filter element is inserted. The two guide elements are spaced from the center plane to ensure not only horizontal guidance of the filter element but also vertical guidance.

[0017] The present invention will be described in detail with reference to preferred embodiments and accompanying drawings.

[0018] A method for providing a filter system for a vacuum pump is, in particular, a method for providing a filter system for a vacuum pump as described above. The method comprises the step of preparing a housing having a housing inlet and a receiving element. A further step of the method is to prepare a filter element for filtering and removing lubricant from a lubricant-gas mixture. The filter element has a filter inlet element, a filter outlet element and a retaining element. The filter inlet element and the housing inlet are configured such that the filter inlet element can be received by the housing inlet in only one position for adjustment. Alternatively, or in addition to such a configuration of the filter inlet element and the housing inlet, the retaining element and the receiving element are configured such that the retaining element can be received by the receiving element in only one position for adjustment. The next step of the method is to insert the filter element into the housing. It is particularly preferable that the insertion is achieved by axially inserting the filter element into the housing by sliding movement.

[0019] Furthermore, it is preferable that the method includes a step of attaching a tension element to the filter system for the vacuum pump in order to generate a holding force. In particular, the holding force acts on a sealing element positioned between the filter element and the housing, thereby resulting in a seal between the filter element and the housing. It is preferable that the tension element is attached between the housing and the filter element, or between the housing cover and the filter element, so that the tension element provides a holding force between the filter element and the housing.

[0020] A preferred further step of this method is to attach a housing cover to the housing to seal and / or retain the filter element within the housing. This attachment is achieved, in particular, by screwing the housing cover to the open end of the housing.

[0021] A method for replacing a filter element of a filter system for a vacuum pump, particularly a filter system for a vacuum pump as described above, has a step of removing a used filter element from the housing of the filter system for the vacuum pump, particularly pulling it out axially. Thereafter, a new filter element is inserted into the housing, preferably axially.

[0022] A method for replacing a filter element of a filter system for a vacuum pump particularly further has a step of removing the housing cover from the housing, particularly loosening the screws, before removing the used filter element.

[0023] A method for replacing a filter element of a filter system for a vacuum preferably further has a step of attaching a tension element as defined in a method of providing a filter system for a vacuum pump and / or a step of attaching a housing cover as defined in a method of providing a filter system for a vacuum pump.

Brief Description of the Drawings

[0024] [Figure 1] It is a schematic cross-sectional view showing the state where the filter system is attached. [Figure 2a] It is a schematic cross-sectional view taken along line II-II of FIG. 1. [Figure 2b] It is a cross-sectional view showing an alternative embodiment of the filter element of FIG. 2a. [Figure 3] It is a schematic cross-sectional view taken along line III-III of FIG. 1. [Figure 4] It is a schematic perspective view showing the filter element. [Figure 5] It is a schematic front view showing the filter system without the housing cover in the direction of arrow V of FIG. 1. [Figure 6] It is a schematic cross-sectional view showing the filter system during assembly.

Embodiments for Carrying Out the Invention

[0025] The filter system of the present invention (Figure 1) comprises a filter element 10 disposed within a filter housing 12. When installed, a filter inlet element 14 connected to the filter element 10 is located at the housing inlet 16 of the filter housing 12. Thus, a mixture of lubricant and gas flows into the filter element 10 through the filter inlet element 14 in the direction of arrow 18. The lubricant filtered out flows radially, particularly from the periphery of the cylindrical filter element 10. Due to gravity, the lubricant flows downward on the outer surface of the filter element 10 and drips from its outer surface. For this purpose, a drip edge 20 is provided on the lower surface of the filter element 10 and extends substantially along the entire longitudinal direction of the filter element 10.

[0026] The lubricant dripping downward from the drip edge 20 hits the inclined upper surface 21, and then returns to the pump generator through the opening 23 due to the pressure difference (the lower pressure inside the pump generator).

[0027] The remaining gas flows through the filter element 10 in the direction of arrow 22, enters the gap 26 between the filter element 10 and the filter housing 12 from the filter outlet element 24, and then exits through the housing outlet 28 of the filter housing 12 in the direction of arrow 30. A schematicly illustrated pressure relief valve 32 is provided on the filter outlet element 24. This pressure relief valve 32 opens when the filter becomes clogged and needs to be replaced. Furthermore, in the illustrated embodiment, a tension element 34 in the form of a coil spring is located inside the filter outlet element 24, which has a cylindrical outer circumference. The coil spring 34 is supported at one end by an intermediate wall 36 and at the other end by the inner surface of the housing cover 38. When installed, the coil spring is compressed so that the filter inlet element 14 is pressed against the left side in Figure 1. As a result, a sealing element located on an annular tab 42 and configured as an O-ring seal 40 in the illustrated embodiment is compressed.

[0028] To adjust to a predetermined position, the filter inlet element 14 has a cross-section, for example, as shown in Figure 2a. Here, the cross-section is not circular but has a flat portion 44. Because the outer shape of the housing inlet 16 is configured accordingly, the filter element 10 can only be inserted at a predetermined position.

[0029] Alternatively, the filter inlet element 14 may have a circular cross-section as shown in Figure 2b. In this case, adjustment is made by a tab 46 that is particularly radially extended and is inserted into a recess provided in the housing inlet 16.

[0030] To facilitate the insertion of the filter inlet element 14 into the housing inlet, two guide elements 48 are provided in the illustrated embodiment (Figure 3). The guide elements 48 extend in the longitudinal direction of the filter element 10, particularly in the area of ​​the housing facing the housing inlet. When the filter element 10 is inserted, the outer surface 50 of the filter element 10 is pushed upward in Figure 1 by the guide elements 48, so that the filter inlet element 14 is positioned at the correct height just before it is inserted into the housing inlet 16. Preferably, the two guide elements 48 are spaced apart from the central surface 52 of the filter element 10. The curvature of the outer surface 50 of the filter element 10 allows for further lateral, i.e., horizontal adjustment.

[0031] Two opposing retaining elements 54 are provided on the outside of the substantially cylindrical filter outlet element 24, either in the region of the filter outlet element 24 or on the side of the filter element 10 facing the housing cover 38 (Figure 4). The two retaining elements 54 shown in the illustrated embodiment are configured as wing-shaped tabs. The wing-shaped tabs are tabs that extend horizontally when installed. The tabs have a longitudinally extending, thickened portion 56 on the outside, which helps to provide more secure adjustment.

[0032] In the installed state, the retaining element 54 (Figure 5) is preferably positioned in a slot-shaped receiving element 58.

[0033] To install the filter element 10, it is inserted to the left into the insertion opening 60 (Figure 6). Two guide elements 48 adjust the position of the filter inlet element 14 relative to the housing inlet 16. Furthermore, the right portion of the filter element 10 in Figure 6 is adjusted by a wing-shaped tab 54 (Figure 5). Initially, there is no tension on the coil spring 34. Therefore, there is no need to apply pressure to the filter outlet element 24 yet. In the next step, the housing cover 38 is placed and secured by four screws 62. Here, the screws 62 engage with the threads 64 (Figure 5) provided in the housing, and the coil spring 34 is already slightly held before it is compressed. By tightening the screws 62, the coil spring 34 is further compressed, and the holding force is also applied to the O-ring seal 40.

[0034] To disassemble it, simply loosen the four screws 62, remove the housing cover 38, and pull out the filter element 10. As soon as the filter element 10 is pulled out, it can be sealed in a plastic bag or similar, thus avoiding the risk of lubricant dripping and consequently contaminating the environment.

Claims

[Claim 1] A filter system for a vacuum pump, A filter element (10) has a filter inlet element (14) and a filter outlet element (24) for filtering and removing lubricant from a lubricant-gas mixture, A housing (12) that accommodates the filter element (10), A housing inlet (16) that accommodates the filter inlet element (14), The retaining element (54) connected to the filter element (10) in the region of the filter outlet element (24), A receiving element (58) is provided on the housing (12) and cooperates with the retaining element (54), It is equipped with, The filter inlet element (14) and the housing inlet (16) are configured such that the filter inlet element (14) can be received by the housing inlet (16) at only one position. The retaining element (54) and the receiving element (58) are configured such that the retaining element (54) can be received by the receiving element (58) at only one position. The retaining element (54) has two wing-shaped tabs that protrude into the two slot-shaped recesses (58) of the receiving element. The filter element (10) is configured to be inserted axially into the housing (12) and / or removed axially from the housing (12), A filter system characterized by the following features.

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