EP3763940A1 - Oil mist separator for a compressor - Google Patents

Abstract

The present invention relates to an oil mist separator (1) for a compressor (2), an annular filter element (9) being arranged in a receiving space (8), a cover (18) closing an assembly opening (15) through which the filter element (9) can be inserted into and removed from the working space (8), the housing (7) having a flange (17) at the assembly opening (15) to which the cover (18) is detachably attached. Maintenance of the oil mist separator ( 1) is simplified if the filter element (9) has an annular filter body (22) and two open end plates (25, 26) if a holding device (29) is provided for holding the filter element (9) in the receiving space (8), which a retaining plate (30) which rests tightly on the end disk (25) facing away from the cover (18), closes the passage opening (27) and provides an oil collection volume (31) on the clean side (11), and has a retaining ring (32), the one facing the cover (18) n end plate (26) rests tightly, has an opening (33) open to the passage opening (28) of this end plate (26) and has a collar (34) which is held axially between the flange (17) and the cover (18). The retaining plate (30) and the retaining ring (32) are axially biased against the filter element (9). An oil suction pipe (37) is fluidically connected to the oil collection volume (31) so that oil can be drawn off from the oil collection volume (31) through the oil suction pipe (37).

Description

The present invention relates to an oil mist separator for a compressor. The invention also relates to a filter element for such an oil mist separator. The present invention also relates to a compressor for generating compressed gas, which is equipped with such an oil mist separator.

A compressor for generating compressed gas comprises a pressure generator for generating a pressurized gas flow, preferably for generating compressed air. A coolant and / or lubricant can be supplied to the pressure generator to reduce friction and / or for cooling. Oil is preferred for this. During operation of the pressure generator, this oil can get into the gas flow in the form of drops or droplets and be carried away or carried along in it. For example, the compressor can be designed as a screw compressor in which two oppositely rotating screws mesh with one another and thereby generate the desired gas flow or gas pressure. These screws can be lubricated with oil to reduce friction and ultimately to increase pressure.

In order to reduce the consumption of oil in the pressure generator or in the compressor and also in order to be able to provide the respective gas as free as possible from entrained oil, such a compressor can be equipped with an oil mist separator. This oil mist separator is arranged downstream of the pressure generator with respect to the gas flow in such a way that the gas flow flows through the oil mist separator and thereby separates the oil droplets carried along in the gas flow as largely as possible.

It is clear that such oil mist separators are also suitable for other machines and can also be used in other machines in which a gas stream is contaminated with oil or another coolant and / or lubricant. The oil mist separator can be used in the respective machine to reduce oil consumption and / or to provide a gas flow that is as pure as possible, that is to say a gas flow with the lowest possible content of oil or other impurities.

The present invention deals with the problem of specifying an improved or at least an alternative embodiment for an oil mist separator or for an associated filter element or for a compressor equipped therewith, which is distinguished by inexpensive maintenance. In addition, a high level of operational reliability is aimed for.

This problem is solved by the subject matter of the independent claims. Advantageous embodiments are the subject of the dependent claims.

The invention is based on the general idea of providing a holding device on which the filter element is interchangeably fixed in an oil mist separator which contains an annular filter element in a receiving space to hold the filter element in the receiving space. The holding device simplifies the assembly and disassembly of the filter element in the receiving space. Furthermore, in the event of maintenance, an old or contaminated filter element can more easily be exchanged for a new or cleaned filter element without the holding device having to be exchanged. Thus, in the event of maintenance, the holding device does not have to be exchanged for a new one, which significantly reduces the financial outlay for maintaining the oil mist separator or the compressor equipped with it.

In detail, the oil mist separator presented here has a preferably cylindrical housing which encloses a preferably cylindrical receiving space. Furthermore, the oil mist separator has an annular filter element which is arranged in the receiving space and in the receiving space separates a raw side lying outside the filter element from a clean side lying inside the filter element. When the oil mist separator is in operation, the flow through the filter element is from the outside to the inside. Furthermore, the oil mist separator comprises a cover for closing an assembly opening in the housing, which is arranged axially on the end face of the housing and through which the filter element can be inserted into the receiving space and removed therefrom. The axial direction of the cylindrical housing is defined by the longitudinal center axis of the cylindrical housing. The axial direction extends parallel to the longitudinal center axis of the housing. The housing also has a radially protruding flange running in the circumferential direction at the assembly opening, to which the cover is releasably attached. The circumferential direction runs around the longitudinal center axis, while the radial direction runs perpendicular to the axial direction. The filter element has an annular filter body and two annular end disks which are arranged on the axial annular ends of the filter body. The respective end disk closes the associated axial annular end of the filter body tightly. Furthermore, the respective annular end disk has an axial through opening.

The oil mist separator according to the invention also has a holding device for holding the filter element in the receiving space. This holding device has a holding plate which lies tightly against the end disk of the filter element facing away from the cover, closes the through opening of this end disk and provides an oil collection volume on the clean side. For example, the retaining plate can be in the area of the through opening of the associated end plate Dome-shaped or concave towards the interior of the filter element. Furthermore, the holding device has a retaining ring which rests tightly on the end disk of the filter element facing the cover, has an opening open to the passage opening of this end disk, and has a radially protruding, circumferential collar. This collar of the retaining ring is held axially between the flange and the cover. For this purpose, the collar covers the flange in the radial direction. In particular, the collar can be braced axially between the flange and cover. In particular, the collar can be integrated into a flange connection which fixes the cover to the flange. Such a flange connection can in particular be formed by several connection points, preferably screw connections, distributed in the circumferential direction. The associated fastening means, preferably screws, can penetrate the flange, the cover and optionally the collar. It is also conceivable to design the screws as threaded pins on the flange or on the cover, so that they then penetrate the respective other component, that is to say the cover or the flange and, if necessary, the collar.

Furthermore, in the case of the oil mist separator presented here, it is provided that the retaining plate and the retaining ring are axially pretensioned against the filter element, which improves the sealing of the end plates with respect to the retaining plate or with respect to the retaining ring. Furthermore, an oil suction pipe is passed through the cover or through the housing and is fluidically connected to the oil collection volume of the holding plate, so that oil can be sucked out of the oil collection volume through the oil suction pipe.

By releasing the connection between the cover and the housing flange, the connection between the retaining ring and the housing is also released, whereby the entire retaining device can be removed from the housing together with the filter element. This simplifies maintenance. By loosening the axial The filter element can be removed and exchanged for another pretension between the retaining plate and retaining ring. As a result, the maintenance of the oil mist separator can be carried out comparatively inexpensively.

According to an advantageous embodiment, the holding device can have a connecting device which connects the holding ring to the holding plate under tensile stress. On the one hand, the tensile stress enables the filter element to be securely held within the holding device. On the other hand, the tensile stress improves the sealing effect between the respective end disk and the retaining ring or the retaining plate.

According to an advantageous further development, the connecting device can have a tie rod which is connected to the holding plate for the transmission of tensile force and which is connected to the retaining ring for the transmission of tensile force via crossbars. This measure enables the desired tensile stress to be achieved in a comparatively simple manner. The tensile forces are also supported exclusively within the holding device, namely on the holding ring and on the holding plate and via the filter element. In this way, a defined tensile stress can be implemented without interaction with the housing or the cover.

According to an advantageous development, the transverse webs can rest axially loosely on the retaining ring in the region of the filter body. Additionally or alternatively, the transverse webs can be welded to the tie rod and form a unit. This unit can be a separate component with respect to the retaining ring, so that the transverse webs only rest loosely axially on the retaining ring. It is also conceivable to fix the transverse webs on the retaining ring, for example by means of a suitable material connection, such as an adhesive connection, a soldered connection or a welded connection.

In another development, it can be provided that the tie rod penetrates the holding plate axially and is axially supported on the holding plate on an outside of the holding plate facing away from the cover. The tensile force transmitted with the aid of the pull rod can in this way be introduced as a compressive force on the holding plate, which considerably simplifies the support of the pull rod on the holding plate. For example, the tie rod can be axially supported on the retaining plate via a nut, this nut being axially fixed on the tie rod. For example, the nut can be screwed onto the pull rod. A material connection between nut and tie rod is also conceivable, that is to say in particular an adhesive connection, a soldered connection or a welded connection.

Another advantageous development provides that the oil suction pipe is arranged next to the pull rod, the oil suction pipe extending axially through between two transverse webs. Thus, the oil suction pipe and the pull rod are separate components that can be optimally positioned independently of one another.

According to an advantageous development, the pull rod can be designed hollow, axially closed at an end facing away from the cover and have at least one radial connection opening in the oil collection volume, so that oil from the oil collection volume reaches the interior of the pull rod. In this embodiment, the oil suction pipe can be inserted into the pull rod and / or connected to it. For example, the oil suction pipe can be inserted so far into the tie rod that the oil suction pipe ends axially in the area of the oil collection volume, so that, for example, an axial opening of the oil suction pipe is below the oil level of the oil collection volume. This allows the oil to be sucked out directly via the oil suction pipe, so that a tight connection of the oil suction pipe to the pull rod is not necessary. With another In the variant, the oil suction pipe is only partially inserted into the pull rod and tightly connected to it. In this case, the axial orifice opening of the oil suction pipe can lie above the oil level of the oil collection volume. A negative pressure in the oil suction pipe can now suck in the oil through the hollow pull rod. Finally, it is also conceivable for the oil suction pipe to be axially sealed directly to the pull rod without the oil suction pipe having to be inserted into the pull rod for this purpose. In this case, too, the oil can be sucked in through the hollow pull rod due to a negative pressure in the oil suction pipe.

Another embodiment, on the other hand, suggests connecting the oil suction pipe to the retaining plate for the transmission of tensile force. In this case, the function of the aforementioned pull rod is integrated into the oil suction pipe without the need for a separate pull rod. Accordingly, this embodiment can be implemented comparatively inexpensively.

According to a further development, the oil suction pipe can penetrate the holding plate and be axially supported on the holding plate on an outside facing away from the cover. A further development is expedient in which the oil suction pipe is axially closed at an end facing away from the cover and has at least one radial connection opening in the oil collecting volume so that oil from the oil collecting volume reaches the oil suction pipe. A plurality of radial connection openings are expediently arranged within the oil collection volume on the oil suction pipe. A further development is also advantageous in which the oil suction pipe is axially supported and / or held on the cover. The oil suction pipe can expediently penetrate the cover axially. In this way, a tensile force for axially bracing the filter element between the retaining plate and the retaining ring can be supported on the cover. The pressure force that occurs here can be supported by the retaining ring and its collar on the cover. In this embodiment, a closed one is in connection with the cover Generates power flow that does not load the housing. Another advantageous development suggests that the oil suction pipe is axially supported on the retaining plate via a nut, which nut is axially fixed on the oil suction pipe. The nut can be fixed to the oil suction pipe, for example by a screw connection or a material connection, such as an adhesive connection, a soldered connection or a welded connection.

According to an advantageous embodiment, the oil suction pipe can be axially fixed on the holding plate, so that a tensile force can be transmitted from the oil suction pipe to the holding plate. This can be done, for example, with a weld nut on the retaining plate within the oil collection volume. The oil suction pipe can also be welded directly to the holding plate. However, an embodiment is preferred in which the oil suction pipe penetrates the holding plate, in particular axially, and is axially supported on the holding plate on an outside of the holding plate facing away from the cover.

Another advantageous embodiment provides that an electrostatically dissipative connection or an electrically conductive connection is configured between the retaining plate and the respective end disk and between the retaining ring and the respective end disk. This at least electrostatically dissipative connection can already be implemented in that the respective end disk is in direct contact with the retaining plate or the retaining ring and is itself made of an electrostatically dissipative or electrically conductive material. The at least electrostatically dissipative connection between the preferably metallic retaining plate or between the preferably metallic retaining ring and the respective end plate enables the respective end plate and, depending on the electrical conductivity of the filter body, also the entire filter element to be grounded or grounded. The holding plate can in turn be electrostatically dissipative or electrically conductive with the retaining ring or with the Be connected to the housing, for example via the suitably metallic tie rod and the suitably metallic cross member. It is also conceivable to manufacture the oil suction pipe from a metal.

In the present context, there is an electrostatically dissipative connection if the surface resistance is at least 100 KΩ and at most 1,000 MΩ, i.e. 1 GΩ. Up to 100 KΩ there is an electrically conductive connection and from 1 MΩ there is an electrically insulating connection. The relevant is the surface resistance, i.e. the electrical resistance measured on the surface of the respective body or component or the respective assembly. According to the standard, the surface resistance is measured at a measuring voltage of 100 V between two parallel electrodes of small width and 100 mm in length, which are 10 mm apart and are in contact with the surface to be measured. In the case of a connection that connects two connection partners of a module, the surface resistance is measured on the respective module across the connection. This means that one electrode on one side of the connection is electrically connected to one connection partner, while the other electrode on the other side of the connection is electrically connected to the other connection partner.

The grounding of the filter element can be of advantage in particular in the case of oil-lubricated compressors that generate high working pressures in order to avoid explosions due to electrostatic discharge if a critical gas-oil mixture forms in the oil mist separator.

According to an advantageous development, the respective electrostatically dissipative connection can have an electrically conductive or an electrostatically dissipative sealing ring, which the respective end disk opposite the retaining plate or seals against the retaining ring. This retaining ring can expediently be braced axially between the respective end disk and the retaining plate or the retaining ring, whereby a particularly favorable electrical contact can be implemented. The sealing ring can consist of an electrically conductive or electrostatically dissipative, but sufficiently elastic plastic.

Furthermore, according to an advantageous embodiment, it can be provided that the end plate is made from an electrically conductive or electrostatically dissipative plastic, so that the large-area contact between the end plate and the retaining plate or between the end plate and the retaining ring leads to the desired earthing or grounding. The plastic can be a mixture in which electrically conductive particles made of metal or carbon, for example carbon fibers, are incorporated into a basically electrically insulating plastic as a matrix. It is also conceivable to manufacture the respective end disk with the aid of an electrostatically dissipative adhesive or from such an adhesive.

In another advantageous embodiment, the holding plate can have at least one axially protruding projection on its inside facing the cover, which engages in an axial recess formed in the respective end plate for centering the filter element with respect to the holding plate. Additionally or alternatively, the retaining ring can have at least one axially protruding projection on its inner side facing away from the cover which engages in an axial recess formed on the respective end disk for centering the filter element relative to the retaining ring. The interaction between the filter element and the holding device via the respective projection and the associated depression simplifies optimal positioning of the filter element in the holding device and thus in the oil mist separator.

According to a further development, a plurality of projections distributed in the circumferential direction can be formed on the holding plate, while a plurality of recesses distributed in the circumferential direction are formed on the respective end disk, in each of which a projection of the holding plate engages. As an alternative to this, a common recess, which is designed as an annular groove and runs in the circumferential direction, into which all the projections of the retaining plate engage, can also be formed on the respective end disk. Additionally or alternatively, a plurality of projections distributed in the circumferential direction can be formed on the retaining ring, while a plurality of depressions distributed in the circumferential direction are formed on the respective end disk, in each of which a projection of the retaining ring engages. Alternatively, a common recess which is designed as an annular groove and runs around in the circumferential direction, into which all the projections of the retaining ring engage, can be formed on the respective end disk. These measures simplify the handling of the filter element and the holding device during maintenance of the oil mist separator. The predetermined position between the filter element and the holding device can be found particularly easily for the respective fitter.

A further development is particularly advantageous in which the respective projection on the holding plate is arranged radially inside a sealing ring which is arranged axially between the holding plate and the respective end disk. The selected positioning improves the sealing effect of the sealing ring. Additionally or alternatively, the respective projection on the retaining ring can be arranged radially inside a sealing ring which is arranged axially between the retaining ring and the respective end disk.

Another embodiment suggests that the filter body has a drainage material and a filter material, the filter material being arranged radially further outward than the drainage material. With a flow through the filter element from radially outside to radially inside, the filter material is therefore first flows through. That is, the drainage material is arranged downstream of the filter material. This ensures that the gas flow is first cleaned of disruptive particles that are retained in the filter material. The drainage material is then flowed through so that any oil carried along can be separated out. This reduces contamination of the drainage material with particles that are carried along in the gas flow.

For this purpose, a gas stream can flow through the drainage material and the filter material. An oil separation effect for oil droplets carried along in the gas flow is expediently greater in the drainage material than in the filter material. In addition, it can be provided as an option that a particle separation effect for solid particles carried along in the gas flow is greater in the filter material than in the drainage material. For example, the drainage material can have a certain adhesive effect for oil and accordingly retain it better in the drainage material. In contrast to this, in the filter material this adhesive effect can be small or absent relative to the drainage material.

Another advantageous embodiment suggests that the filter body has at least one metal grid through which the gas flow can flow and which connects the two end plates to one another. In particular with regard to the above-described earthing or grounding of the filter element, an electrically conductive or an electrostatically dissipative connection can be established between the two end plates with the aid of this metal grid. The build-up of electrical or electrostatic voltage due to ionization during operation of the oil mist separator can thereby be minimized. The metal grid can be cylindrical. Furthermore, it can be arranged radially inward on the filter body in order to define a pressure-stable support for the rest of the filter body there. For example, the above-mentioned drainage material can be supported radially on the inside on this metal grid. This metal grille is also conceivable or to arrange a further metal grid radially between the aforementioned drainage material and the aforementioned filter material, so that, for example, the filter material can be supported radially on the inside on this metal grid. The filter material can expediently be folded in a star shape. Additionally or alternatively, the drainage material can in principle also be folded in a star shape.

A filter element according to the invention is suitable and intended for use in an oil mist separator of the type described above. For this purpose, the filter element can have at least one axial recess on at least one of its end disks axially on the outside, which interacts with an axial projection on the retaining ring or on the retaining plate. Additionally or alternatively, such a filter element can also be characterized in that it has electrically conductive or electrostatically dissipative end plates and a metal grid in the filter body, which connects the two end plates to one another in an electrically conductive or electrostatically dissipative manner.

A compressor according to the invention for generating compressed gas has a pressure generator for generating a pressurized gas flow and an oil mist separator of the type described above. The oil mist separator in the compressor is arranged downstream of the pressure generator with respect to the gas flow. The pressure generator can be lubricated with oil. The pressure generator can also work with screws. In particular, the compressor can thus be an oil-flooded screw compressor.

Further important features and advantages of the invention emerge from the subclaims, from the drawings and from the associated description of the figures with reference to the drawings.

It goes without saying that the features mentioned above and those yet to be explained below can be used not only in the respectively specified combination, but also in other combinations or alone, without departing from the scope of the present invention.

Preferred exemplary embodiments of the invention are shown in the drawings and are explained in more detail in the following description, with the same reference symbols referring to the same or similar or functionally identical components.

Fig. 1

einen Längsschnitt durch einen Ölnebelabscheider,

Fig. 2

einen Längsschnitt durch den Ölnebelabscheider wie in Fig. 1, jedoch bei einer anderen Ausführungsform,

Fig. 3

eine auseinandergezogene Darstellung des Ölnebelabscheiders aus Fig. 1,

Fig. 4

einen Längsschnitt des Ölnebelabscheiders im Bereich einer Halteeinrichtung und eines Filterelements,

Fig. 5

eine vergrößerte Ansicht eines Details V in Fig. 4.

They show, each schematically,

Fig. 1

a longitudinal section through an oil mist separator,

Fig. 2

a longitudinal section through the oil mist separator as in Fig. 1 , but in a different embodiment,

Fig. 3

an exploded view of the oil mist separator Fig. 1 ,

Fig. 4

a longitudinal section of the oil mist separator in the area of a holding device and a filter element,

Fig. 5

an enlarged view of a detail V in Fig. 4 .

According to the Fig. 1 and 2 An oil mist separator 1 can form a component of a compressor 2, which has as a further component a pressure generator 3, shown here only symbolically, which serves to generate a pressurized gas flow 4 which is fed into the Fig. 1 , 2 and 4th indicated by arrows is. With regard to this gas flow 4, the oil mist separator 1 is arranged in the compressor 2 downstream of the pressure generator 3. The gas stream 4 accordingly flows through the oil mist separator 1. An inlet for the gas stream 4 laden with oil is in FIG Fig. 1 marked with 5. An outlet for the gas stream 4 freed from the oil is in Fig. 1 denoted by 6. The compressor 2 can be designed as an oil-flooded screw compressor. In any case, the gas stream 4 coming from the pressure generator 3 can be loaded with oil in the form of oil droplets.

According to the Figures 1 to 3 the oil mist separator 1 has a cylindrical housing 7 which encloses a receiving space 8. Furthermore, the oil mist separator 1 has an annular filter element 9 which is arranged in the receiving space 8 and which in the receiving space 8 separates a raw side 10 lying radially outside the filter element 9 from a clean side 11 lying radially inside the filter element 9. The axial direction is indicated in the figures by a double arrow and denoted by 12. The axial direction 12 is defined by a longitudinal center axis 13 of the housing 7. As a result, the axial direction 12 extends parallel to the longitudinal center axis 13. When the ring filter element 9 is arranged concentrically in the cylindrical housing 7, a longitudinal center axis 14 of the filter element 9 also coincides with the longitudinal center axis 13 of the oil mist separator 1.

The housing 7 has a mounting opening 15 through which the filter element 9 can be inserted into the receiving space 8 and removed therefrom. At this assembly opening 15, the housing 7 has a radially protruding flange 17 running around the circumference 16. The circumferential direction 16 is indicated in FIG. 3 by a double arrow and runs around the longitudinal center axis 13. The oil mist separator 1 is also equipped with a cover 18 which is used to close the assembly opening 15. For this purpose, the cover 18 is on Flange 17 is releasably fastened, for example by a flange connection 35. Corresponding connection points or fastening elements 19 are in the Fig. 1 and 2 indicated by dash-dotted lines and can be formed by screw connections. The fastening elements 19 can pass through openings 20 on the flange side and openings 21 on the cover side, the openings 21 of the cover 18 expediently being arranged in axial overlap with the openings 20 of the flange 17.

The filter element 9 has an annular filter body 22 through which the gas stream 4 can flow radially and thereby has the desired oil separation effect and possibly a particle separation effect. An embodiment is preferred in which the filter body 22 has an annularly arranged drainage material 23 as well as a separately annularly arranged filter material 24 for this purpose. Drainage material 23 and filter material 24 are preferably arranged in filter body 22 in such a way that, during operation, gas stream 4 first flows through filter material 24. When the filter element 9 flows through radially from the outside to the inside, the filter material 24 is arranged radially further outside than the drainage material 23. The filter material 24 and / or drainage material 23 can be designed and folded in web form and accordingly form a pleated star. The drainage material 23 is chosen so that an oil separation effect in the drainage material 23 for oil droplets entrained in the gas stream 4 is greater than in the filter material 24. The filter material 24 is expediently designed so that in the filter material 24 a particle separation effect for solid particles entrained in the gas stream 4 is greater than in the Drainage material 23. The filter body 22 is tightly closed at its axial frontal and annular ends with the aid of an annular end disk 25, 26, one or first end disk 25 being arranged at one axial end of the filter body 22, while the other or second end disk 26 is arranged at the opposite other axial end of the filter body 22. Both end plates 25, 26 are as designed open end plates so that they each have an axial through opening 27 and 28, respectively.

The oil mist separator 1 is also equipped with a holding device 29, with the aid of which the filter element 9 is held in the receiving space 8. For this purpose, the holding device 29 has a holding plate 30 which lies tightly against the first end disk 25 facing away from the cover 18. The holding plate 30 closes the through opening 27 of the first end disk 25 and provides an oil collection volume 31 or an oil collection space 31 on its inside facing the cover 18, that is, on the clean side 11. In the in the Fig. 1 and 2 In the mounted state shown, the filter element 9 is upright in the housing 7, that is to say mounted with a vertical longitudinal center axis 14. The first end disk 25 and thus the holding plate 30 are arranged at the bottom of the filter element 9. As a result, the oil collection volume 31 is open at the top, so that oil collecting on the clean side 11 collects in the oil collection volume 31 due to gravity.

The holding device 29 is also equipped with a holding ring 32 which lies tightly against the second end disk 26 facing the cover 18. The retaining ring 32 has an opening 33 that is open to the through opening 28 of the second end disk 26. In addition, the retaining ring 32 has a radially protruding collar 34 running around the circumference 16, which is held axially between the flange 17 and the cover 18. Appropriately, this collar 34 can protrude radially so far into the flange connection 35 formed between cover 18 and flange 17 that the collar 34 is also fixed in this flange connection 35 with the aid of the fastening elements 19. For example, the collar 34 can have openings 36 for this purpose, which are axially penetrated by the fastening elements 19 and which for this purpose are aligned in axial overlap with the openings 20, 21 of flange 17 and cover 18. A suitable seal can be integrally formed in the collar 34 within the flange connection 35 be, for example by at least one closed circumferential bead, which can be formed by deformation on the collar 34. Appropriately, however, at least one separate seal can be used here. In the Figs. 1 to 3 there is shown an washer seal 46 made according to FIG Fig. 1 and 3 is arranged axially between the collar 34 and the cover 18, that is, on the clean side. Optionally, another washer seal 46 can also be present, which in the example of FIG Fig. 1 and 3 is then arranged axially between the collar 34 and the flange 17. In the example of Fig. 2 only one washer seal 46 is also provided within the flange connection 35, but in contrast to the Fig. 1 is arranged axially between the flange 17 and the collar 34. It is also conceivable here to optionally provide a further annular disk seal 46, which is then arranged axially between the collar 34 and the cover 18. The respective annular disk seal 46 can also be integrated into the flange connection 35 and have corresponding openings 38 for this purpose, which are aligned axially with the openings 20, 21, 36 of flange 17, cover 18 and collar 34.

In the assembled state, the holding plate 30 and the holding ring 32 generate an axial bracing of the filter element 9, as a result of which it is securely held on the housing 7 via the holding device 29.

The oil mist separator 1 is also equipped with an oil suction pipe 37, which can preferably be passed through the cover 18 and which is fluidically connected to the oil collection volume 31, so that oil can be suctioned from the oil collection volume 31 through the oil suction pipe 37.

In the example shown, the retaining ring 32 is equipped at its opening 33 with an axially protruding annular collar 38 running around the circumference, which engages in the through opening 28 of the second end disk 26 and thereby radially can come to rest on an opening edge 39 of the second end disk 26. Furthermore, the retaining ring 32 is stepped here in the area of the second end disk 26, so that the retaining ring 32 is connected to the collar 34 via a cylinder section between an annular disk section resting on the second end disk 26. As a result, an outflow space 39 is defined between the cover 18 and the retaining ring 32, which is open to the interior 40 of the filter element 9. The gas outlet 6 is fluidically connected to this outflow space 39 through the cover 18, for example.

In the example of Fig. 1 and 3 the holding device 29 is also equipped with a connecting device 41 which connects the holding ring 32 to the holding plate 30 under tensile stress. This connecting device 41 can expediently have a pull rod 42 which is connected to the holding plate 30 for the transmission of tensile force and which is connected to the retaining ring 32 for the transmission of tensile force via transverse webs 43. For example, these transverse webs 43 can rest axially on the retaining ring 32 in the region of the filter body 22, in particular loosely. In the example shown, the pull rod 42 expediently penetrates the holding plate 30 in the area of the oil collecting volume 31 and is axially supported on the holding plate 30 on its outer side facing away from the cover 18. For example, the pull rod 42 can be axially supported on the holding plate 30 via a nut 44, which nut is axially fixed to the pull rod 42 in a suitable manner. The nut 44 is expediently screwed onto a corresponding thread of the pull rod 42. In Fig. 1 a tensile force curve 45 is indicated by arrows, which shows the force flow for holding the filter element 9 in the housing 7 in a pretensioned manner. Starting from the nut 44, the power flow 45 goes via the tie rod 42 into the cross member 43 and from there via the retaining ring 32 to the cover 18 or to the flange connection 35 Retaining ring 32 supported. In the example of Fig. 1 that happens Oil suction pipe 37 separate from and in addition to pull rod 42, that is to say next to pull rod 42 and extends through between two cross struts 43.

Fig. 2 shows another embodiment of the holding device 29. In the case of FIG Fig. 2 No additional connecting device 41 is provided in the embodiment shown. In this embodiment, the oil suction pipe 37 is connected to the holding plate 30 for transmission of tensile force. In this respect, the oil suction pipe 37 is used here as a pull rod. For this purpose, the oil suction pipe 37 can be axially fixed on the holding plate 30 in such a way that a tensile force can be transmitted from the oil suction pipe 37 to the holding plate 30. This traction transmission 45 is also in Fig. 2 again indicated by an arrow. It can be seen that the tensile force 45 is transmitted directly to the cover 18, while the counterforce is transmitted to the cover 18 or the flange connection 35 via the retaining plate 30, the filter element 9 and the retaining ring 32. In this embodiment, the oil suction pipe 37 penetrates the holding plate 30 axially, expediently in the area of the oil collection volume 31. The oil collection pipe 37 is supported in a suitable manner on the outside of the holding plate 30 facing away from the cover 18 on the holding plate 30. This, too, can expediently take place again via a nut 48 which is axially fixed in a suitable manner on the oil suction pipe 37. In the simplest case, the nut 48 is screwed onto a complementary thread of the oil suction pipe 37. The oil suction pipe 37 is axially closed at an end facing away from the cover 18 and has at least one radial connection opening 49 in the oil collecting volume 31. Accordingly, oil can enter the oil suction pipe 37 from the oil collecting volume 31 through the respective connection opening 49 and in this way can be sucked out of the oil collecting volume 31 through the oil suction pipe 37. In addition, the oil suction pipe 37 is axially fixed in a suitable manner on the cover 18 in order to be able to transmit the desired transmission of tensile force for generating the axial tensioning of the filter element 9 from the holding plate 30 to the cover 18. For example, can a nut not shown here may also be provided here. The oil suction pipe 37 can also be welded into the cover 18.

In the examples of the Figs. 1 to 4 the oil collecting volume 31 is formed with the aid of a cup-shaped central area 61 of the holding plate 30, which merges via a horizontal inner annular disk area 62 into a vertical cylinder area 63 which merges into a horizontal outer annular disk area 64. The lower end disk 25 is supported axially on the outer annular disk area 64 and radially on the cylinder area 63. As a result, on the one hand, the sealing surface between the holding plate 30 and the lower end disk 25 is improved, while on the other hand, the volume of the oil collecting space 31 is increased.

Independently of the respective embodiment of the holding device 29, the advantageous embodiments of the filter element 9 described below can be implemented additionally or alternatively or in any combination. For example, an electrically conductive or an electrostatically dissipative connection 50 can be formed between the retaining plate 30 and the first end disk 25 and / or between the retaining ring 32 and the second end disk 26. The and combination is preferred, so that both end disks 25, 26 are connected to the holding device 29 in an at least electrostatically dissipative manner. First, the two end plates 25, 26 are in direct contact with the mounting plate 30 or with the retaining ring 32 in the assembled state under axial pretension, which inevitably means that an at least electrostatically dissipative connection 50 is already present if the individual connection partners are electrically conductive or electrostatically dissipative are designed. Due to the high forces, the holding plate 30 and the holding ring 32 are expediently metal components, in particular shaped sheet metal parts. The retaining plate 30 and retaining ring 32 are expediently uncoated or unpainted and in particular consist of one corrosion-resistant material, preferably stainless steel. It is also conceivable to manufacture the end plates 25, 26 from an electrically conductive or an electrostatically dissipative material, in particular from an electrically conductive or electrostatically dissipative plastic, preferably from an electrically conductive or electrostatically dissipative adhesive. This already results in an electrically conductive or at least one electrostatically dissipative connection 50 due to the contact between the end disks 25, 26 and retaining plate 30 or retaining ring 32. To improve the electrical conductivity here, the respective electrical or electrostatic connection 50 can be connected to the respective end plate 25, 26 each be equipped with an electrically conductive or electrostatically dissipative sealing ring 51. This sealing ring 51 seals the respective end disk 25, 26 with respect to the retaining plate 30 or with respect to the retaining ring 32. The sealing ring 51 is inserted into an axially open annular groove 52 formed on the respective end disk 25, 26.

In the Figures 4 and 5 a further advantageous embodiment is shown, which is also used in the Figs. 1 to 3 shown embodiments can be implemented accordingly. In the Figures 4 and 5 a state is shown in which the filter element 9 is not yet clamped axially between the retaining plate 30 and retaining ring 32, so that the sealing rings 51 are not yet axially compressed. Accordingly, a gap 53 can be seen between the end disks 25, 26 and the holding plate 30 or the holding ring 32. In the fully assembled state, the respective gap 53 is eliminated, so that there is direct contact between the respective end disk 25, 26 and the holding plate 30 or the holding ring 32.

According to Fig. 4 For example, the holding plate 30 may have at least one axially protruding projection 54 on its inside facing the cover 18, which engages in an axial recess 55 formed on the first end plate 25 for centering the filter element 9 with respect to the holding plate 30. Additionally or alternatively can according to the Figures 4 and 5 the retaining ring 32 have at least one axially protruding projection 56 on its inside facing away from the cover 18, which engages in an axial recess 57 formed on the second end disk 26 for centering the filter element 9 with respect to the retaining ring 32. The holding plate 30 can have a plurality of projections 54 distributed in the circumferential direction 16. A single, annular, circumferential projection 54 is also conceivable. A plurality of depressions 55 distributed in the circumferential direction 16 can be formed on the first end plate 25, so that each projection 54 engages in a separate depression 55. It is also conceivable to provide an annular recess 55 on the first end plate 25, into which all separate projections 54 or the annular projection 54 can engage. A plurality of projections 56 distributed in the circumferential direction 16 can be formed on the retaining ring 32, each of which engages in a recess 57 of the second end disk 26 or which engages in a common, annular recess 57 formed on the second end disk 26. It is also conceivable to form an annular projection 56 on the retaining ring 32, which then engages in the annular recess 57.

According to the Figures 4 and 5 the respective projection 54 of the retaining plate 30 or the respective projection 56 of the retaining ring 32 is arranged radially inside the sealing ring 51, which improves the centering and sealing.

In the embodiments shown here, the filter body 22 has at least one cylindrical metal grid 58, 59. Two such metal grids 58, 59 are shown in each of the examples. The respective metal grid 58, 59 can be flowed through by the gas stream 4 and connects the two end disks 25, 26 to one another mechanically and electrically or electrostatically. The drainage material 23 can be radially supported on the first metal grid 58 arranged radially further inward. The second metal grid 29, which is arranged radially further outward, is arranged radially between the drainage material 23 and the filter material 24. On this second Metal grid 29 can support the filter material 24 radially. In the example of Fig. 2 the filter body 22 additionally has a prefilter material 60 which is also arranged cylindrically and which is arranged radially on the outside of the filter material 24 so that the gas stream 4 flows through first the prefilter material 60 and then the filter material 24 during operation.

Claims (15)

Oil mist separator (1) for a compressor (2), - With a cylindrical housing (7) which encloses a receiving space (8), - With an annular filter element (9) which is arranged in the receiving space (8) and in the receiving space (8) separates a raw side (10) lying outside the filter element (9) from a clean side (11) lying inside the filter element (9), - With a cover (18) for closing an assembly opening (15) of the housing (7), which is arranged axially on the end face of the housing (7) and through which the filter element (9) can be inserted into and removed from the working space (8) , - The housing (7) having a radially protruding flange (17) extending in the circumferential direction (16) to which the cover (18) is detachably attached to the assembly opening (15), - wherein the filter element (9) has an annular filter body (22), - The filter element (9) having an annular end disk (25, 26) at each of the axial annular ends of the filter body (22) which tightly closes the respective axial end of the filter body (22) and which has an axial passage opening (27, 28) having, - wherein the oil mist separator (1) also has a holding device (29) for holding the filter element (9) in the receiving space (8), - The holding device (29) having a holding plate (30) which rests tightly on the end disk (25) facing away from the cover (18), the through-opening of which (27) closes and provides an oil collection volume (31) on the clean side (11), - wherein the holding device (29) has a retaining ring (32) which rests tightly on the end plate (26) facing the cover (18), has an opening (33) open to the through opening (28) of this end plate (26) and a radial one has protruding, in the circumferential direction (16) circumferential collar (34) which is held axially between the flange (17) and the cover (18), - wherein the retaining plate (30) and the retaining ring (32) are axially biased against the filter element (9), - The oil mist separator (1) also having an oil suction pipe (37) which is fluidically connected to the oil collection volume (31) so that oil can be sucked out of the oil collection volume (31) through the oil suction pipe (37). Oil mist separator (1) according to claim 1,
characterized, - That the holding device (29) has a connecting device (41) which connects the holding ring (32) to the holding plate (30) under tensile stress, - That the connecting device (41) has a tie rod (42) which is connected to the holding plate (30) for the transmission of tensile force and which is connected to the retaining ring (32) for the transmission of tensile force via transverse webs (43), - that the transverse webs (43) in the area of the filter body (22) rest axially on the retaining ring (32), - That the tie rod (42) penetrates the holding plate (30) and is supported axially on the holding plate (30) on its outer side facing away from the cover (18). Oil mist separator (1) according to claim 2,
characterized,
that the oil suction pipe (37) runs next to the tie rod (42) and extends through between two transverse webs (43). Oil mist separator (1) according to claim 1,
characterized,
that the oil suction pipe (37) is connected to the retaining plate (30) for the transmission of tensile force. Oil mist separator (1) according to claim 1 or 4,
characterized, - that the oil suction pipe (37) is axially fixed on the retaining plate (30), - That the oil suction pipe (37) is axially closed at an end facing away from the cover (18) and has at least one radial connection opening (49) in the oil collecting volume (31), so that oil from the oil collecting volume (31) passes into the oil suction pipe (37) , - That the oil suction pipe (37) is axially supported and / or held on the cover (18). Oil mist separator (1) according to one of Claims 1 to 5,
characterized,
that between the retaining plate (30) and the respective end plate (25) and between the retaining ring (32) and the respective end plate (26) at least one electrostatically dissipative connection (50) is formed. Oil mist separator (1) according to claim 6,
characterized,
that the respective at least electrostatically dissipative connection (50) has an at least electrostatically dissipative sealing ring (51) which seals the respective end disk (25, 26) with respect to the retaining plate (30) or with respect to the retaining ring (32). Oil mist separator (1) according to one of Claims 1 to 7,
characterized,
that the respective end plate (25, 26) is made of an at least electrostatically dissipative plastic. Oil mist separator (1) according to one of Claims 1 to 8,
characterized, - That the holding plate (30) on its inside facing the cover (18) has at least one axially protruding projection (55) which is opposite in an axial recess (55) formed on the respective end plate (25) for centering the filter element (9) the retaining plate (30) engages, and / or - That the retaining ring (32) has at least one axially protruding projection (56) on its inner side facing away from the cover (18), which protrudes into an axial recess (57) formed on the respective end plate (26) for centering the filter element (9) engages the retaining ring (32). Oil mist separator (1) according to claim 9,
characterized, - That a plurality of projections (54) distributed in the circumferential direction (16) are formed on the holding plate (30), while a plurality of recesses (55) distributed in the circumferential direction (16) are formed on the respective end plate (25), in each of which a projection (54) engages the retaining plate (30), or a recess (55) designed as an annular groove, extending in the circumferential direction (16), into which all projections (54) of the retaining plate (30) engage, and / or - That several projections (56) distributed in the circumferential direction are formed on the retaining ring (32), while several projections (56) are formed on the respective end plate (26) Circumferential direction (16) distributed depressions (57) are formed, in each of which a projection (56) of the retaining ring (32) engages, or a recess (57) formed as an annular groove, extending in the circumferential direction (16), into which all the projections (56) of the retaining ring (32). Oil mist separator (1) according to claim 9 or 10,
characterized, - That the respective projection (54) on the holding plate (30) is arranged radially inside a sealing ring (51) which is arranged axially between the holding plate (30) and the respective end plate (25), and / or - That the respective projection (56) on the retaining ring (32) is arranged radially inside a sealing ring (51) which is arranged axially between the retaining ring (32) and the respective end plate (26). Oil mist separator (1) according to one of Claims 1 to 11,
characterized, - That the filter body (22) has a drainage material (23) and a filter material (24), - That the filter material (24) is arranged radially further out than the drainage material (23), - that the drainage material (23) and the filter material (24) can be flowed through by a gas stream (4), - that in the drainage material (23) an oil separation effect for oil droplets entrained in the gas stream (4) is greater than in the filter material (24), - It can be provided in particular that a particle separation effect for solid particles entrained in the gas flow (4) is greater in the filter material (24) than in the drainage material (23). Oil mist separator (1) according to one of Claims 1 to 12,
characterized,
that the filter body (22) has at least one cylindrical metal grid (58, 59) through which the gas stream (4) can flow and which connects the two end disks (25, 26) to one another. Filter element (9) for an oil mist separator (1) according to one of Claims 8 to 13. Compressor (2) for generating compressed gas with a pressure generator (3) for generating a pressurized gas flow (4) and with an oil mist separator (1) according to one of Claims 1 to 13, which is downstream of the pressure generator (3) with respect to the gas flow (4) is arranged.

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