SEPARATOR FOR SEPARATING A LOWER DENSITY LIQUID FROM A FLUID STREAM

Abstract

The invention relates to a separator for separating a lower density liquid, in particular an oil, from a fluid stream containing a mixture of a gas, the lower density liquid and a higher density liquid, in particular water, the separator having a supply, through which the fluid stream can flow under overpressure, and a decompression chamber having a decompression opening, which can be connected via the decompression opening to an environment in which a pressure level lower than the overpressure of the fluid stream prevails, and a coalescence filter arranged in the decompression chamber and an interior space surrounded by a coalescence filter medium, the supply opening into the interior, and a separation chamber, which is arranged below the decompression chamber and having an upper outlet for lower density liquid and a lower outlet for a residual product, and having a dip tube having a first opening in the lower region of the decompression chamber and a second opening in the separation chamber.

Claims

1. A separator (10) for separating a lower density liquid, in particular an oil, from a fluid stream containing a mixture of a gas, the lower density liquid and a higher density liquid, in particular water, the separator having a supply (11) through which the fluid stream can flow a) under overpressure or b) a pressure which is below an overpressure and wherein the fluid can be pressurized via a pressure line, and a decompression chamber (12) having a decompression opening (13), which can be connected via the decompression opening (13) to an environment in which a pressure level lower than the pressure of a) the fluid stream prevails or b) the pressurized fluid prevails, and a coalescence filter (15), which is arranged in the decompression chamber (12) and has an interior space (16) at least partially surrounded by a coalescence filter medium (17), the supply (11) opening into the interior space (16), and a separation chamber (20) arranged below the decompression chamber (12) and having an upper outlet (21) for lower density liquid and a lower outlet (22) for a residual product, and having a dip tube (23) having a first opening (24) in the lower region of the decompression chamber (12) and a second opening (26) in the separation chamber (20).

2. The separator (10) according to claim 1, characterized in that a particle filter (41) is arranged in the interior space (16) of the coalescence filter (15).

3. The separator (10) according to claim 1 or 2, characterized by a guide plate (27), which is arranged opposite to the second opening (26) of the dip tube (23) within the separation chamber (20).

4. The separator (10) according to one of claims 1 to 3, characterized in that the upper outlet (21) is an overflow.

5. The separator according to one of claims 1 to 4, characterized in that an activated carbon filter (33) is connected downstream the lower outlet (22).

6. The separator (10) according to one of claims 1 to 5, characterized in that a liquid level sensor (29) is arranged in the separation chamber (20).

7. The separator (10) according to one of claims 1 to 6, characterized in that the lower outlet (22) is closed by a valve (30) and/or that a pump is connected downstream the lower outlet (22).

8. A method of separating a lower density liquid, particularly an oil, from a fluid stream containing a mixture of a gas containing the lower density liquid and a higher density liquid, in particular water, the method comprising the following steps: supplying the fluid stream a) under overpressure via a supply (11) into the interior space (16) of a coalescence filter (15) or b) below overpressure into the interior space (16) of a coalescence filter (15) and pressurizing the supplied fluid via a pressure line, the coalescence filter (15) is arranged in a decompression chamber (12) and the interior space (16) of which is at least partially surrounded by a coalescence filter medium (17), passing of the lower density liquid and the higher density liquid through the coalescence filter medium (17), collecting the lower density liquid and the higher density liquid in a lower region of the decompression chamber (12), conveying the lower density liquid and the higher density liquid through a dip tube (23) into a separation chamber (20), the dip tube (23) having a first opening (24) in the lower region of the decompression chamber and a second opening (26) in the separation chamber (20), and floating at least a part of the lower density liquid on a residual product in the separation chamber (20).

9. The method according to claim 8, characterized in that the pressure level in the decompression chamber (12) is lower than a) the overpressure of the fluid stream in the supply (11) and/or b) the pressure in the pressure line.

10. The method according to claim 8 or 9, characterized in that the liquid level in the separation chamber (20) is measured by means of a liquid level sensor (29) and depending on the measured liquid level, a valve (30) closing the lower outlet (22) is activated and/or a pump connected downstream of the lower outlet (22) is activated.

11. The method according to one of claims 8 to 10, characterized in that the lower density liquid is oil and/or the higher density liquid is water.

12. A use of a separator (10) according to one of claims 1 to 7 for separating a lower density liquid, in particular an oil, from a fluid stream containing a mixture of a gas, the lower density liquid and a higher density liquid, in particular water.

13. A compressed air system (1) having a component that introduces water and oil into the compressed air and a separator (10) according to one of claims 1 to 7.

14. A method for exchanging a coalescence filter (15) and/or a particle filter (41) in a separator (10) according to one of claims 1 to 7, characterized by removing a coalescence filter (15) located in the decompression chamber (12) and/or removing a particle filter (41) located in the decompression chamber (12) and inserting a coalescence filter (15) into the decompression chamber (12) and/or inserting a particle filter (41) into the decompression chamber (12).

15. A use of a coalescence filter (15) and/or a particle filter (41) for performing the method according to claim 14.

Description

[0114] The invention is explained with reference to a drawing illustrating only embodiments of the invention. Shown therein:

[0115] FIG. 1 a schematic view of a compressed air system;

[0116] FIG. 2 a schematic view of a separator according to the invention;

[0117] FIG. 3 a schematic representation of a separation chamber having deflection pot and dip tube of a separator according to the invention;

[0118] FIG. 4 a perspective top view of a part of a coalescence filter with part of a particle filter of a separator according to the invention, which part of a particle filter can be inserted into the interior space of the coalescence filter, but is arranged next to the coalescence filter in the view of FIG. 4;

[0119] FIG. 5 a perspective top view of a part of a coalescence filter with part of a particle filter of a separator according to the invention, which part of a particle filter can be inserted into the interior space of the coalescence filter, arranged in the coalescence filter in the view of FIG. 5;

[0120] FIG. 6 a schematic view of an alternative construction of a separator according to the invention; and

[0121] FIG. 7 a sectional view through a coalescence filter, as it can be used in a separator according to the invention.

[0122] FIG. 1 shows a schematic representation of a compressed air system 1. The compressed air system 1 has a feed inlet 2, via which air enters the system. The air can be fresh air, but it can also be a return flow from a compressed air pipeline network. The compressed air system 1 has a compressor. 3 This compressor can be, for example, an oil injected screw compressor. The compressor 3 compresses the air entering via the feed inlet 2 and thus generates compressed air. The compressed air generated by the compressor 3 is supplied to a filter 5 via a cyclone separator 4. The compressed air thus supplied is supplied via a further line to a cooling dryer 6. The dried and filtered compressed air leaving the cooling dryer 6 via a line can be fed into a compressed air pipeline network 7 indicated only schematically.

[0123] The cyclone separator 4, the filter 5 and the cooling dryer 6 each have a condensate discharge line 8, which in each case transfer condensate accumulating in the cyclone separator 4, the filter 5 or the cooling dryer 6 into a condensate collecting line 9. The condensate collecting line 9 leads to a separator 10 for separating a lower density liquid, namely an oil from a fluid stream, namely the condensate stream in the condensate collecting line 9, which condensate stream contains a mixture of a gas, namely air, of the lower density liquid, namely oil, and a higher density liquid, namely water.

[0124] The compressed air located after the compressor 3 in the pipeline system has a higher pressure than the atmosphere. Thus condensate, which is drained into the cyclone separator 4, the filter 5 or the cooling dryer 6 also has a higher pressure than the atmosphere. The pressure level applied specifically in the condensate collecting line 9 depends on the flow resistance over the separator 10 according to the invention, in particular on the flow resistance of the coalescence filter 15 or the coalescence filters 15. If the coalescence filter 15 is free, then a lower pressure level is established in the condensate collecting line 9 than when the coalescence filter 15 has already been clogged up and thus has a higher flow resistance. Then the pressure level in the condensate collecting line 9 is higher.

[0125] The separator according to the invention shown in FIG. 2 for separating a lower density liquid, namely an oil from a fluid stream, which contains a mixture of a gas, namely air, the lower density liquid, namely oil and a higher density liquid, namely water, has a supply 11, through which the fluid stream can flow under pressure. The supply 11 is a pipeline running within a decompression chamber 12, which adjoins the condensate collecting line 9. The decompression chamber 12 has a decompression opening 13.

[0126] The decompression chamber 12 is designed pot-like, so that the decompression opening 13 can make up the complete open cross-section at the upper end of the pot. But it is also conceivable that the decompression chamber 12 is closed by a (not shown) lid and has a vent hole. Due to the expected pressure conditions and flow velocities, it is to be expected that a relatively small hole is sufficient to establish the pressure balance between the interior of the decompression chamber 12 and the ambient pressure. A filter 14 is arranged in the decompression opening 13, which filter can bind odors and/or volatile organic carbon. The interior of the decompression chamber 12 can be connected to the environment of the decompression chamber 12 via the decompression opening 13. A pressure level lower than the overpressure of the fluid stream prevails in the environment of the decompression chamber 12. Particularly preferably, ambient pressure prevails in the environment of the decompression chamber 12.

[0127] A coalescence filter 15 is arranged in the decompression chamber 12. The coalescence filter has an interior space 16. The interior space 16 is partially surrounded by a coalescence filter medium 17. In this case, the coalescence filter medium 17 has a hollow cylindrical shape and also forms the bottom 18 of the coalescence filter 15. In addition, the coalescence filter 15 has a lid 19. The lid 19 has an opening, to which the supply 11 is connected and through which the condensate stream flows into the interior space 16 of the coalescence filter 15, so that the supply 11 opens into the interior space 16.

[0128] A separation chamber 20 is arranged below the decompression chamber 12. The separation chamber has an upper outlet 21 for lower density liquid and a lower outlet 22 for a residual product, which can also be the higher density liquid.

[0129] A dip tube 23 is provided. The dip tube 23 has a first opening 24 in the lower region of the decompression chamber 12, namely in the bottom 25 of the decompression chamber 12. Furthermore, the dip tube 23 has a second opening 26 in the separation chamber 20.

[0130] A guide plate 27 is provided in the separation chamber 20. The guide plate 27 forms the bottom of a deflection pot 28. The second opening 26 of the dip tube 23 is located within the deflection pot 28.

[0131] A liquid level sensor 29 is provided in the separation chamber 20. The liquid level sensor measures the liquid level of the residual liquid in the separation chamber 20.

[0132] The lower outlet 22 is closed by a valve 30. The position of the valve body of the valve 30 can be changed based on a signal from the liquid level sensor 29. This makes it possible to transfer the valve from a closed position to an open position. Furthermore, in a preferred embodiment, it is possible to change the degree of opening of the valve 30 based on signals from the liquid level sensor.

[0133] The upper outlet 21 is designed as an overflow. An overflow pipeline 31 connects to it. A fluid can flow from the separation chamber 20 into a collection container 32 via the overflow pipeline 31.

[0134] An activated carbon filter 33 is connected downstream the valve 30. The liquid emerging through the valve 30 can be conducted through the activated carbon filter 33 to a discharge 34.

[0135] The separation chamber 20 has a turbidity sensor 35, with which the turbidity of the residual product can be determined. Furthermore, a UVC light source 36 is provided on the separation chamber 20, with which UV light can be radiated into the separation chamber 20.

[0136] For separating the lower density liquid, namely oil, from a fluid stream, namely the condensate stream conducted through the condensate collecting line, which contains a mixture of a gas, namely air, the lower density liquid, namely oil or a higher density liquid, namely water, the condensate stream flowing through the condensate collecting line 9 under overpressure is introduced into the interior space 16 of the coalescence filter 15 via the supply 11.

[0137] It is conceivable that, when the separator 10 is commissioned, the fluid stream under overpressure initially only decompresses in the interior space 16 of the coalescence filter 15, without there being any appreciable liquid passage through the coalescence filter medium. In such a case, the mixture of gas, oil and water initially collects in the interior space of the coalescence filter, wherein due to the pressure release during the first time flowing into the interior space of the coalescence filter after commissioning of the separator, there can initially be a lack of a pressure gradient between the interior space 16 of the coalescence filter 15 and the remainder of the interior of the decompression chamber 12. However, the longer the condensate stream is introduced via the supply 11 into the interior space 16 of the coalescence filter, the more the level of the mixture in the interior space 16 of the coalescence filter 15 will increase. If the interior space 16 of the coalescence filter 15 is filled with a mixture, further addition of mixture through the supply 11 results in an overpressure being created in the interior space 16 of the coalescence filter 15 with respect to the interior of the decompression chamber 12. This overpressure pushes the mixture through the coalescence filter medium 17 of the coalescence filter 15. As the mixture passes through the coalescence filter medium 17, smaller droplets of the lower density liquid, namely oil, coalesce into larger droplets and/or droplets of the higher density liquid, namely water, into larger droplets, wherein larger droplets of mixture can also form. The larger drops, as far as they have passed through the sidewalls of the coalescence filter medium, run downwards on the outer surface of the coalescence filter medium, following the principle of gravity. The droplets passing through the bottom 18 of the coalescence filter medium 17 and the droplets that follow gravity on the outer peripheral area of the coalescence filter medium 17 are released from the coalescence filter medium 17 by gravity and drip downward as shown in FIG. 2. The drops on the bottom 25 of the decompression chamber 12 form a liquid level 37. The mixture of oil and water, which forms the liquid level 37, passes by gravity through the first opening 24 in the dip tube 23 and leaves the dip tube 23 through the second opening 26 within the deflection pot 28. The fluid stream emerging from the second opening 26 is deflected by the guide plate 27 and flows upwards. The oil drops flow upwards due to the lower density. There is a separation, so that an oil layer 38 floats on a residual product 39. It can be assumed in this case that the proportion of oil droplets in the residual product 39 is lower the closer the considered region of the residual product 39 is to the bottom 40 of the separation chamber 20. It can be assumed that the regions of the residual product 39, which are located in the immediate vicinity of the bottom 40, consist only of water and are free of oil.

[0138] The liquid level of the residual product 39 in the separation chamber 20 increases through the addition of mixture through the dip tube 23 in the separation chamber 20, as long as the valve 30 is closed or the valve 30 is opened only so far that the volume flow flowing through the valve 30 is less than the volume flow passing through the second opening 26.

[0139] If the oil layer 38 reaches the upper outlet 21, it acts as an overflow and oil enters the overflow pipeline 31 and enters the collection container 32 through the overflow pipeline 31.

[0140] If the level of the residual product 39 reaches the liquid level sensor 29, there is the possibility of it changing the position of the valve 30, for example, to open the valve 30 or, for example, to change the degree of opening of the valve 30. If the valve 30 is opened, residual product 39 located in the vicinity of the lower outlet 22 flows through the lower outlet 22 and the valve 30 into the activated carbon filter 33. Here, the residual product 39 is freed from further residues and can then be discharged via the discharge 34. It is to be assumed that the liquid discharged using the discharge 34 is completely or, within the legal regulations, almost completely free from residues.

[0141] FIG. 3 shows that the deflection pot 28 is open at the top and thus has an upper opening through which the dip tube 23 protrudes into the deflection pot 28, so that the second opening 26 of the dip tube 23 is located in deflection pot 28. If the dip tube 23 protruding into the deflecting pot 28 were not present, this opening of the deflecting pot would have a cross-sectional area A1 in a horizontal plane. Due to its presence, the dip tube 23 protruding into the deflection pot 28 reduces the opening area of the deflection pot 28. In the same horizontal plane, the dip tube 23 has a cross-sectional area A2 predetermined by its outer circumference in this plane. For the passage of liquids upwards in the deflection pot 28, the annular residual area remaining around the dip tube 23 thus remains having the size A1 minus A2.

[0142] The deflection pot 28 is arranged in the separation chamber 20 with a hollow cylindrical wall, namely in a pot-shaped separation chamber 20. If the deflection pot 28 arranged in the separation chamber 20 with a hollow cylindrical wall were not present, the separation chamber 20 would have a cross-sectional area A3 in a horizontal plane. The deflection pot 28 arranged in the separation chamber 20 with hollow cylindrical wall narrows due to its presence the free cross-sectional area A3 of the separation chamber 20. In the same horizontal plane, the deflection pot 28 has a cross-sectional area A1′ predetermined by its outer circumference in this plane (wherein in a first approximation, namely neglecting the wall thickness of deflection pot A1′=A1). For the passage of liquids through the free cross-section of the separation chamber 20 in this horizontal plane past the outside of the deflection pot 28, for example, a sinking of liquid in the direction of the bottom of the separation chamber 20, the annular residual area remaining around the deflection pot thus remains having the size A3 minus A1′ (which in a first approximation corresponds to A3 minus A1). Preferably (A3−A1)=(A1−A2)=20 to 50×A2.

[0143] The liquid level 70 of the lower density liquid is further indicated in FIG. 3. This is in the operating situation shown in FIG. 3 is in alignment with the lower edge of the upper outlet 21. Also shown is the phase boundary 71 between the oil layer 38 floating on the residual product 39 and the residual product 39. The liquid level sensor 29 is arranged so as to detect when the phase boundary 71 falls to a height H. The height H is the distance between the upper edge of deflection pot 28 and the phase boundary. The outer peripheral surface of a (imaginary and indicated by dashed lines in FIG. 3) hollow cylindrical body, which adjoins the top of the deflection pot, can be described with the height H and the radius/diameter of deflection pot 28. In a preferred embodiment, the method according to the invention is performed such that the phase boundary 71 has at least the distance H from the upper edge of the deflection pot, so that the liquid upwardly rising in the deflection pot 28 and passing through the surface (A1-A2) is supplied a hollow cylindrical passage area of H×2×π×√(A1/π) extending over the upper edge of deflection pot 28 to the phase boundary 28. Thus, the liquid rising in the deflection pot 28 is given enough space below the phase boundary 71 in order to flow radially outward over the upper edge of deflection pot 28 and down the outside the deflection pot 28 towards the bottom 40 of the separation chamber 20.

[0144] FIG. 4 shows a perspective view of a part of the coalescence filter 15 and of a part of the particle filter 41, which can be used in the context of the separator 10 according to the invention. FIG. 4 shows the part associated with the coalescence filter 15 and the part associated with the particle filter 41 in the disassembled state. The part belonging to the coalescence filter 15 and the part belonging to the particle filter 41 are designed in this design as DOE cartridges (double open end cartridges). They are supplemented by an upper end plate (not shown in FIG. 4) and a lower cover plate (not shown in FIG. 4) for forming the coalescence filter 15 and the particle filter 41.

[0145] The part of the coalescence filter 15 shown in FIG. 4 has an upper end ring 42, an outer support grid 43 and a lower end ring 48. The upper end ring 42 has an opening 44. The outer circumference of the upper end ring 42 merges into the outer circumference of the outer support grid 43. As a result, a support is created with which the coalescence filter 15 can be placed on a support of the decompression chamber 12 and thus maintained in a fixed spatial relationship to the other elements of the decompression chamber 12. The coalescence filter 15 further has an inner support grid 45. A hollow cylindrical coalescence filter medium 17 is arranged between the inner support grid 45 and the outer support grid 43. The interior space of the coalescence filter 15 is surrounded by the hollow cylindrical coalescence filter medium 17.

[0146] The particle filter 41 has an upper end ring 52, an outer support grid 53 and a lower end ring 50. The upper end ring 52 has an opening 54. The outer circumference of the upper end ring 52 merges into the outer circumference of the outer support grid 53. This creates a shoulder. The particle filter 41 further has an inner support grid 55. A hollow cylindrical particle filter medium 49 is arranged between the inner support grid 55 and the outer support grid 53 (a pleated particle filter medium can also be used). The interior space of the particle filter 41 is surrounded by the hollow cylindrical particle filter medium 49.

[0147] FIG. 5 shows the state in which the part of the particle filter 41 illustrated in FIG. 4 has been inserted into the interior space 16 of the coalescence filter 15. The upper end ring 52 thereby sits in the opening 44. To form a coalescence filter 15, the parts shown in FIG. 5 can be closed above and below by an (not shown in FIG. 4 and FIG. 5) upper end plate having an opening aligned with the opening 54 and with a (not shown in FIG. 4 and FIG. 5) lower end plate. For this purpose, O-rings are placed on the upper end ring 42, the upper end ring 52 and under the lower end ring 48 and under the lower end ring 50 and placed thereon, or below the upper end plate and the lower end plate. The upper end plate and the lower end plate are clamped together by clamping elements.

[0148] As a result, tight chambers are formed, which cause the liquid to be able to enter only through the opening aligned with the opening 54 and can escape only after passing through the particle filter medium 49 and after passing through the coalescence filter medium 17 on the outer peripheral surface of the coalescence filter 15.

[0149] FIG. 7 shows a sectional view through a coalescence filter, as it can be used in a separator according to the invention. As in the embodiment shown in FIGS. 4 and 5, the coalescence filter 15 has an upper end ring 42, an outer support grid 43, and a lower end ring 48. The outer circumference of the upper end ring 42 merges into the outer circumference of the outer support grid 43. The coalescence filter 15 further has an inner support grid 45. A hollow cylindrical coalescence filter medium 17 is arranged between the inner support grid 45 and the outer support grid 43. The interior space of the coalescence filter 15 is surrounded by the hollow cylindrical coalescence filter medium 17. The particle filter 41 has an upper end ring 52, an outer support grid 53 and a lower end ring 50. The upper end ring 52 has an opening 54. The outer circumference of the upper end ring 52 merges into the outer circumference of the outer support grid 53. The particle filter 41 further has an inner support grid 55. A hollow cylindrical particle filter medium 49 is arranged between the inner support grid 55 and the outer support grid 53 (a pleated particle filter medium can also be used). The interior space of the particle filter 41 is surrounded by the hollow cylindrical particle filter medium 49.

[0150] Furthermore, an upper end plate 60 and a lower end plate 61 are shown in FIG. 7. The upper end plate 60 has a circumferential outer annular groove 62, in which the upper end ring sits in a form-fitting. In the outer annual groove 62 an O-ring is placed (not depicted in FIG. 7). The upper end plate 60 has a circumferential inner annular groove 63, in which the upper end ring 52 sits in a form-fitting . In the inner annual groove 63 an O-ring is placed (not depicted in FIG. 7). The upper end plate 60 has a connecting piece 64 having an internal thread, which serves as a supply 11 and by means of which the coalescence filter 15 can be screwed to the end of a (indicated by dashed lines in FIG. 7) pipeline network. A support ring 65 supported by spokes is provided In the connecting piece 64. A (not shown in FIG. 7) threaded pin can be guided by the support ring 65 and screwed into the internal thread 66 in the lower end plate 61. The threaded pin penetrates the support ring 65, so that a nut screwed onto the threaded pin from above can be brought into abutment with the support ring 65 from above. The clamping force can be adjusted by tightening the nut, with which force the upper end plate 60 and the lower end plate 61 are pressed onto the elements arranged therebetween.

[0151] The lower end plate 61 has a circumferential outer annular groove 67, in which the lower end ring sits in a form-fitting. In the outer annual groove 67 an O-ring is placed (not depicted in FIG. 7). The lower end plate 61 has a circumferential inner annular groove 68, in which the lower end ring 50 sits in a form-fitting. In the inner annual groove 68 an O-ring is placed (not depicted in FIG. 7).

[0152] A hole 69 is provided in the upper end plate 60, a pressure sensor 46 being arranged with a signal line 47 at the end of said hole (alternatively a pressure measuring point can be provided). The pressure sensor 46 can measure the pressure in the annular chamber between the outer circumference of the particle filter 41 and the inner circumference of the coalescence filter medium 17.

[0153] A pressure sensor 56 is provided with a signal line 57 in the pipeline network above the connecting piece 64 (alternatively a pressure measuring point can be provided). The pressure sensor 56 measures the pressure present in the pipeline network and thus the pressure in the interior of the particle filter 41.

[0154] The coalescence filter 15 shown in FIG. 7 can be arranged suspended in a decompression chamber 12. For example, the protrusion between the upper end plate 60 and the outer support grid 43 can be used as a support for a support ring. Likewise, it is conceivable to place the coalescence filter 15 with the lower end plate 61 on a platform provided with legs and placed on the bottom 25 of the decompression chamber 12.

[0155] The pressure difference across the particle filter medium 49 can be measured by evaluating the measurement results of the pressure sensor 46 and the pressure sensor 56. If one considers the thus measured pressure difference over time, then information about the state of the particle filter medium 49 can be derived therefrom. If the pressure difference reaches a certain value, it can be concluded that the particle filter medium 49 has been clogged up to some degree and the particle filter 41 can need to be replaced. If the measured pressure difference falls below a certain value, then it is to be expected that the particle filter medium is cracked.

[0156] By evaluating the measurement results of the pressure sensor 46 and assuming that atmospheric pressure prevails inside the decompression chamber 12, the pressure difference across the coalescence filter medium 17 can be measured. If one considers the thus measured pressure difference over time, then information about the state of the coalescence filter medium 17 can be derived therefrom. If the pressure difference reaches a certain value, it can be concluded that the coalescence filter medium 17 has been clogged up to some degree and the coalescence filter 15 may need to be replaced. If the measured pressure difference falls below a certain value, then it is to be expected that the coalescence filter 17 medium is cracked.

[0157] FIG. 6 shows the possibility that the decompression chamber 12 can also have two coalescence filters 15. A valve 58 can be provided in the supply 11. Using this valve 58, there can be control over the fluid stream being conducted from the condensate collecting line 9 into the interior space 16 of the coalescence filters 15 regarding into which interior 16 or in what ratio relative to each other. In this case, operating positions are conceivable in which the condensate stream is conducted solely into the interior space 16 of the right coalescence filter, with which the left coalescence filter 15 becomes free for replacement. It is also conceivable to direct the condensate alone into the left coalescence filter 15 into the interior space 16 of the left coalescence filter 15, while the right coalescence filter 15 remains free, for example, to be replaced. It is also conceivable to direct condensate both into the interior space 16 of the right coalescence filter 15 and into the interior space 16 of the left coalescence filter 15, for example, in order to be able to work off peaks in the volume flow of the condensate.

[0158] According to the embodiment shown in FIG. 6, a common liquid level 37 is formed, which can be conducted via a common dip tube 23 into a common separation chamber 20. It is of course also possible to change the relative position of the dip tube 23 relative to the two coalescence filters 15, for example, to arrange the dip tube 23 in the middle.

[0159] In an alternative embodiment, it is conceivable to have a decompression chamber 12 interact with two dip tubes 23 and two separation chambers 20. In this case, one would arrange the first dip tube 23 below the right coalescence filter 15 and the second dip tube below the left coalescence filter. The two dip tubes can either be conducted into the same separation chamber 20 or it is even conceivable to provide two separate separation chambers.

[0160] The use of multiple coalescence filters 15 in a separator offers the possibility of different types of process control. Thus, a process control is conceivable in which the liquid is primarily passed through a coalescence filter 15 while the supply 11 is closed to a second coalescence filter 15, for example, by a pressure relief valve. The second coalescence filter 15 is used for support, for example, in the event of a sudden accumulation of liquid. In such an operating situation, the resulting higher pressure in the condensate collecting line 9 can lead to opening of the pressure relief valve and lead to a part of the abruptly accumulated larger amount of liquid flowing through the second coalescence filter 15. In such operation, the first coalescence filter 15 gradually primarily clogs up, while the second coalescence filter 15 remains almost unused. If, after a certain period of operation, the coalescence filter 15 becomes so clogged up that it has to be exchanged, the liquid can be diverted to the second (virtually unused) coalescence filter 15 and the supply 11 to the first coalescence filter 15 can be blocked. The first coalescence filter 15 can then be exchanged. During further operation, the liquid is primarily led over the coalescence filter that remained in the system and the replaced coalescence filter takes over the task of a reserve position.

[0161] It is also conceivable to provide a plurality of separators 10 within the compressed air system shown in FIG. 1.