liquid separator

Abstract

Liquid separator (200; 202) for separating oil and / or oil aerosol from compressed air, wherein the liquid separator (200; 202) has a cylindrical pressure-resistant container (110) with a raw air inlet (114), in particular arranged radially, wherein the raw air inlet (114) is connectable to a connection component (300) in the form of a compressor element, and wherein the raw air inlet (114) is configured to admit compressed air containing liquid from the connection component (300) into the pressure-resistant container (110), and wherein a filter insert (120) with at least one separating element (122) configured as an annular coalescer is arranged in the pressure-resistant container (110), wherein the separating element (122) is configured to separate oil and / or oil aerosol from the compressed air containing liquid. is characterized by a sensor drainage unit (100; 102; 104) comprising the sensor drainage unit - at least one drainage pipe element (20, 22) for draining oil that collects in the filter insert (120) of the liquid separator (200; 202), which is designed to return the oil separated by coalescence from the filter insert (120) directly or indirectly to the compressor element and - at least one level sensor (10) designed for contactless measurement of the level of the oil accumulating in the filter insert (120) and designed to supply at least one valve (30) with at least one signal dependent on the measured level, wherein the level sensor (10) is associated with the drainage pipe element (20; 22) and is arranged either inside the drainage pipe element (20; 22) or directly outside the drainage pipe element (20; 22).

Description

Technical field

[0001] The invention relates to a liquid separator according to the preamble of claim 1. State of the art

[0002] Liquid separators, such as oil separators for removing oil aerosols from air, can be used, for example, to remove oil from compressed air in compressed air systems supplied by an oil-lubricated connection element, such as a compressor element or a vacuum pump element. Such a liquid separator has a filter element designed to separate oil from air and a pressure-resistant container for the connection component.

[0003] The oil-laden air flows into the pressure-resistant container via a raw air inlet, then passes through the filter insert, which has at least one filter element or separator element designed to separate oil from raw air, for example a main separator and a post-separator, and finally leaves the housing in a cleaned state via the clean air outlet.

[0004] The filter element operates on the coalescence principle. The at least one hollow cylindrical filter element is designed as an annular coalescer, which clumps the fine oil droplets together into larger oil droplets that settle downwards by gravity within the air-dewatering element and downstream of it. The settled oil droplets are drained away via at least one drainage line or pipe.

[0005] The air oil removal elements used on compressors remove the compressor oil injected for cooling and sealing the stage from the compressed air to approximately one to three mg / m³. 3The residual oil content is removed, and the oil separated by coalescence is collected in an oil collection area radially arranged within the separating element of a bottom end disc of the filter insert. From there, the separated oil is returned to the pressure stage of the compressor or compressor stage via at least one drainage pipe element. During compressor operation, the problem arises that the oil level rises to varying degrees when different operating points are reached. It is known to install an orifice in the drainage pipe to adjust the drainage rate. To accommodate the different operating conditions, the prior art design the drainage rate for the compressor's operating point with the highest fluid level. To prevent the fluid level in the air-oil separator from rising too high, oil and compressed air are continuously extracted via the drainage pipe.Thus, in current technology, oil and compressed air are continuously extracted via a drain pipe permanently connected to the pressure stage, whereby too much compressed air is extracted via the drain pipe during the majority of operating time. The continuously extracted compressed air is not available as usable compressed air, resulting in a continuous energy loss. This is particularly disadvantageous for modern machines with variable speed control (Vr), which are often operated in the partial load range.

[0006] A sensor drainage unit is disclosed in German patent application DE 10 2009 014 744 A1. This document describes a method for the discontinuous emptying of a container in which liquid separated by a liquid separator of a fuel cell system accumulates. A liquid sensor for detecting the level of the separated liquid and a valve that is switched depending on this fill level are arranged in this container. The liquid sensor and the valve are separate units, independent of the liquid separator and the drainage pipe.

[0007] An oil separator with a device for automatically draining the separated oil is disclosed in US patent 3980457 A. This oil separator has means for detecting the liquid level of the separated oil, namely a float with a magnetic switch. This float is a magnetic switch for the drainage system. The oil separator belongs to a series of separators and filters, such as those used after a compressor, and serves for the further treatment of pre-cleaned compressed air. There is no connection from the oil separator to the compressor by which the separated oil could be returned to the compressor. Therefore, the separated oil cannot reach the compressor's pressure stage.

[0008] DE 693 03 447 T2 describes a vacuum pump device with an oil mist filter device for separating lubricating oil from the cleaning gas for the drive motor with a gas outlet and a drain line for the collected lubricating oil, wherein the collected lubricating oil is drawn in by an oil pump and mixed with lubricating oil from the storage tank.

[0009] A filter element for air oil removal with a modular drainage device is described in DE 101 31 108 A1.

[0010] US Patent 2004 / 0050804A1 describes a method for draining water separated from fuel from a collection chamber.

[0011] From DE 10 2006 033 343 A1, a drainage device with capacitive sensors for draining liquids from an air pipe connected to a collection chamber is known. Depending on the signals from two sensors arranged at different heights, a drain valve is controlled to drain the liquid from the collection chamber.

[0012] US Patent 5,616,856 A describes a method for detecting the boundary between two phases in a multiphase fluid using ultrasound.

[0013] US 2017 0 327 369 A1 describes an adapter set for oil drums with a filling tube and a drain tube, wherein a level sensor is arranged in the drain tube to determine the oil level in the oil drum.

[0014] DE 11 2014 002 317 T5 discloses a device for the return of exhaust gas treatment fluid.

[0015] The invention is based on the objective of further developing a liquid separator of the type mentioned above in such a way that the fill level of the liquid accumulating in the pressure-resistant container can be easily detected. In particular, the drainage rate should be easily controllable depending on the fill level of the liquid, and losses should be minimized. For example, it should be prevented that the drainage pipe draws air out of the pressure-resistant container when the fill level drops below a defined value. Disclosure of the invention

[0016] This problem is solved by a liquid separator having the features specified in claim 1. Advantageous embodiments and expedient further developments of the present invention are characterized in the dependent claims.

[0017] The present invention is based on integrating the level sensor into the drainage pipe, in particular into an element or a section of the drainage pipe, for example by attaching it to or within the drainage pipe. The drainage pipe (element) and the level sensor form a single unit. The invention therefore relates to a unit comprising at least one element of a drainage pipe with an integrated non-contact level sensor, or a unit comprising a non-contact level sensor with an integrated drainage pipe (element).

[0018] The level sensor can be integrated into the drainage pipe element or positioned directly on its outer circumference. The level sensor is thus arranged on the drainage pipe in such a way that it measures the level of the liquid collecting in the pressure-resistant container either directly through the drainage pipe or directly around its outer circumference.

[0019] The drainage pipe features a valve designed to control the drainage rate, with the valve's operation dependent on the fill level measured by the level sensor. Thus, the opening of the drainage pipe depends on the liquid level in the pressure vessel. This has the advantage that only the precise amount of liquid and compressed air required for the application is extracted. In other words, the drainage rate depends on the liquid level in the pressure vessel, particularly the liquid level in the liquid separator, for example, the liquid level in the filter element. The drainage rate can vary according to the different operating points of the connected component, i.e., the compressor.

[0020] With the aid of the present invention, it is possible to measure the collected liquid volume or drainage volume without further mechanical processing of the pressure-resistant container and the liquid separator. Compared to the prior art, this results in significant savings in installation costs when initially equipping a sensor drainage unit or a liquid separator.

[0021] The level gauge can also be designed to measure other values, such as temperature and / or pressure, in the pressure-resistant container.

[0022] The pressure-resistant container is connected to a connection component in the form of a compressor element. The pressure-resistant container has a raw air inlet, which is connected to the connection component and is configured to admit compressed air containing liquid, originating from the connection component, into the pressure-resistant container. The raw air inlet can, for example, be arranged radially on the pressure-resistant container.

[0023] To return the liquid accumulating in the pressure-resistant container to the connection component, in particular to the pressure stage or sump of the connection component, the drainage pipe is connected to the connection component, for example to a compressor screw. In this way, liquid separated in the pressure-resistant container can be fed to the pressure stage or sump of the connection component, in particular the compressor, via the drainage pipe. According to the invention, the drainage pipe is thus designed to return the liquid separated by the filter element via coalescence directly or indirectly to the pressure stage or sump of the connection component.

[0024] The level sensor and the valve can be designed as a single unit or as separate elements that can be arranged at different locations along the drainage pipe. In an advantageous embodiment of the present invention, the level sensor is attached to or arranged within the drainage pipe, and the signal output of the level sensor and the signal input of the valve are arranged separately. The level sensor can be connected to the valve or to a control unit that controls the valve, either via cable or wirelessly.

[0025] A level sensor and valve can be integrated into a drainage pipe known from the prior art. The level sensor can be arranged in or on a drainage pipe as described in claim 1. The drainage pipe can be designed, for example, like the drainage pipe described in German patent applications DE 20 2006 002 383 U1, DE 101 31 108 A1, or EP 1 695 753 B1. The present invention can therefore be retrofitted into a conventional drainage pipe. The level sensor measures the level of the liquid, which collects in the pressure-resistant container and is separated by coalescence, without contact, for example, using a laser or ultrasound. For example, to determine the level, the level sensor can project a laser or ultrasound beam through the drainage pipe or pass very close to the drainage pipe.

[0026] Advantageously, the sensor drainage unit can be attached to a liquid outlet of the pressure-resistant container, which is designed to discharge the liquid accumulating within it. The drainage pipe can advantageously be arranged such that it extends through the liquid outlet of the pressure-resistant container, for example, through the pipe-side liquid outlet of a lid of the pressure-resistant housing, and projects into the interior of the pressure-resistant container. For example, the sensor drainage unit can have at least one fixing element for attaching it to the liquid outlet of the pressure-resistant container.

[0027] To separate liquid in the form of oil and / or oil aerosol from the liquid-laden compressed air, a filter insert with at least one separating element designed as an annular coalescer, in particular made of fiberglass and / or plastic, such as nonwoven fabric, is arranged in the pressure-resistant container. The level sensor of the drainage unit is designed to measure the level of the liquid separated by coalescence and accumulating in the pressure-resistant container.

[0028] In an advantageous embodiment of the liquid separator of the present invention, the pressure-resistant container has a lid to close its end face. The lid has a clean air outlet on the clean side, in particular arranged axially, for releasing the compressed air cleaned by the filter element. The clean air outlet can be connected to the connection component to return the clean air cleaned by the filter element.

[0029] The lid is advantageously removable, and in particular screwable onto the pressure-resistant container. The filter element is advantageously replaceable and arranged within the pressure-resistant container. For mounting the filter element within the pressure-resistant container, the filter element can have a flange on its end face, which can be clamped between the lid of the pressure-resistant container and the cylindrical body of the pressure-resistant container. The flange can, for example, be arranged coaxially with the clean air outlet.

[0030] To cover the axial end face of the separator element of the filter insert facing away from the flange, the filter insert advantageously has an axial end plate. For collecting the liquid separated by the separator element, this axial end plate has a liquid collection area, in particular an oil collection area, arranged radially within the separator element. The drainage pipe projects into the separator element up to the liquid collection area. The level sensor measures the fill level of the liquid collection area arranged radially within the separator element without contact, either through the drainage pipe or directly alongside it. In this embodiment, the present invention enables a simple level measurement for measuring the fill level of liquid separated by coalescence in a liquid separator arranged in a pressure vessel, for example, a compressor.

[0031] Finally, the present invention relates to the use of a liquid separator of the type described above for the removal of oil from compressed air in a compressed air system which is supplied by an oil-lubricated connection element in the form of a compressor element. Brief description of the drawings

[0032] As discussed above, there are various ways to advantageously elaborate and further develop the teaching of the present invention. For this purpose, reference is made, on the one hand, to the claims subordinate to claim 1, and on the other hand, further embodiments, features, and advantages of the present invention are described below, inter alia, with reference to the Fig. Examples 1 to 13 are explained in more detail. It shows: Fig. 1: in schematic cross-sectional view a first embodiment of a liquid separator according to the present invention with a first embodiment of a sensor drainage unit; Fig. 2: A second embodiment of a sensor drainage unit according to the present invention is shown schematically, wherein the level sensor of the sensor drainage unit is designed as a laser sensor; Fig. 3: in schematic representation an embodiment of a sensor drainage unit not according to the invention, wherein the level sensor of the sensor drainage unit is designed as a rod probe; Fig. 4: schematically depicts the filter insert and the sensor drainage unit of the liquid separator. Fig. 1; Fig. 5: In schematic cross-sectional representation, a second embodiment of a liquid separator according to the present invention, wherein the drained oil is led to a raw-side oil collection volume of the pressure-resistant container; Fig. 6: Schematic representation of a compressed air system of a compressor with the liquid separator made of Fig. 1, wherein the drained oil is returned directly to the compressor screw; Fig. 7: Schematic representation of a compressed air system of a compressor with the liquid separator made of Fig. 1, wherein the drained oil is returned to the compressor screw via an intermediate tank and a pump; Fig. Figure 8 shows a schematic representation of a compressed air system of a compressor with a liquid separator made of Fig. 1, wherein the drained oil is returned to the compressor screw via an intermediate tank; Fig. 9: Schematic representation of a compressed air system of a compressor with the liquid separator made of Fig. 1, wherein the drained oil is conveyed via an intermediate tank and a pump to a raw-side oil collection volume of the pressure-resistant container; Fig. 10 in schematic cross-sectional view the liquid separator made of Fig. 1 with the sensor drainage unit from Fig. 2; Fig. 11 in schematic cross-sectional view the liquid separator made of Fig. 1 with the non-inventive sensor drainage unit made of Fig. 3; Fig. 12 in isometric representation the liquid separator from Fig. 10 and Fig. 13 in isometric representation the non-inventive liquid separator made of Fig. 11.

[0033] Identical or similar designs, elements, or features are found in the Fig. Numbers 1 to 13 are labelled with identical reference symbols. embodiment(s) of the invention

[0034] To avoid unnecessary repetition, the following explanations regarding the embodiments, features and advantages of the present invention (unless otherwise stated) refer both to those described in the Fig. 1, Fig. 4 and Fig. 5 shown sensor drainage unit 100 as well as on the in the Fig. 2, Fig. 6, Fig. 7, Fig. 8, Fig. 9, Fig. 10 and Fig. 12 shown sensor drainage unit 102 as well as on the in the Fig. 3, Fig. 11 and Fig. 13 illustrated sensor drainage unit 104. Furthermore, the following explanations regarding the embodiments, features and advantages of the present invention (unless otherwise specified) refer both to the one shown in the Fig. 1, Fig. 6, Fig. 7, Fig. 8, Fig. 10, Fig. 11, Fig. 12 and Fig. 13 liquid separators 200 as well as on the ones in the Fig. 5 and Fig. 9 liquid separators shown 202.

[0035] Based on the Fig. 1, Fig. 6, Fig. 7, Fig. 8, Fig. 10, Fig. 11, Fig. 12 and Fig. Figure 13 illustrates a first embodiment of a liquid separator 200 of the present invention, showing an air-oil removal element 200 which operates according to the method of the present invention.

[0036] The air-oil separator 200 is replaceably arranged in a cylindrical, pressure-resistant container 110, namely a pressure storage container. The pressure storage container 110 has a radially arranged raw air inlet 114, which is connected to a compressor element 300, namely a compressor screw. Whenever terms such as radial, axial, coaxial, circumferential, or the like are used herein, unless otherwise stated, this refers to the longitudinal axis of the air-oil separator 200.

[0037] The compressor screw 300 is part of a compressed air system 400, which is located in the Fig. 6 to 9 is shown.

[0038] Compressed air loaded with oil aerosol enters the pressure storage tank 110 via the raw air inlet 114. To separate oil from air, the air-oil separator 200 has a filter insert 120 with, for example, two separator elements 122 designed as ring-shaped coalescers. The separator elements 122 can be made of the same or different materials, for example, fiberglass and / or plastic, such as nonwoven fabric. The raw air flowing in through the raw air inlet 114 flows through the separator elements 122 from radially outside to radially inside. To ensure that the separator elements 122 can withstand the pressure of the airflow and retain their shape, each separator element 122 is arranged around a support tube 128. This support tube 128 is typically made of perforated sheet metal with air passages or expanded metal with air passages.

[0039] For storing the filter element 120 in the pressure storage vessel 110, the filter element 120 has a flange 124. In the operating position, the filter element 120 is arranged in the pressure storage vessel 110 in a replaceable manner, with the flange being held and sealed between the lower part 126 of the pressure storage vessel and the lid 118.

[0040] The purified clean air flows out of the pressure storage vessel 110 in an axial direction. To discharge the clean air, the housing cover 118 of the pressure storage vessel 110 has a central clean air outlet 116. As shown in the Fig. 1, Fig. 5, Fig. 12 and Fig. As shown in Figure 13, the axial clean air outlet 116 can be designed in a tubular form.

[0041] The oil, which is separated by the separating elements 122 of the filter insert 120, collects inside the cylindrical filter insert 120 at a foot-side end disc 130 of the filter insert 120, in particular in an oil collection area 140 arranged radially inside the filter insert 120 of the foot-side end disc 130, and is discharged via a drainage pipe element 20, 22 and fed back to the compressor element 300.

[0042] Oil collects in a foot-mounted oil collection volume 150 at the bottom of the housing body 126 of the pressure storage vessel 110. This oil is separated by a pre-separation process within the pressure vessel 110, primarily by gravity and centrifugal force during the tangential inflow of raw air. The pre-separated oil, which collects in the oil collection volume 150, is also returned to the compressor element 300 via a liquid outlet 112, which is designed to discharge the liquid accumulating in the pressure-resistant vessel 110.

[0043] The drainage pipe element 20, 22, designed to drain the oil separated by coalescence, can be formed in one piece ( Fig. 1) or consist of several drainage pipe elements 20, 22 or drainage pipe sections ( Fig. 2 and Fig. 3) The drainage pipe element 20, 22 can be a drainage pipe known from the prior art, which is placed from the outside through the pressure vessel lid 118 into the inner area of ​​the air de-oil element 200 and, by means of the operating pressure, returns oil from the pressure storage vessel 110 to the stage.

[0044] According to the invention, a level sensor is integrated into the drainage pipe element 20, 22 to improve the regulation of the drainage volume. This reduces drainage losses and significantly increases the efficiency of the compressor 300.

[0045] To retrofit a conventional air-oil separator with the sensor drainage unit 100, 102, 104 according to the invention, the sensor drainage unit 100, 102, 104 can be integrated into an existing drainage pipe 22. The level sensor 10 can then be installed in the existing drainage pipe 22. For example, an existing drainage pipe 22 coming from the pressure storage tank 110 can be cut open, and a sensor drainage unit 100, 102, 104 can be arranged between the cut drainage pipe 22.

[0046] Alternatively, the sensor drainage unit 100, 102, 104 can have a drainage pipe element 20 with an integrated level sensor 10, whereby this drainage pipe element 20 can be installed into the existing drainage pipe 22, for example, by screwing it in. Alternatively, the level sensor 10 can also be arranged directly on the outside of the drainage pipe element 20, 22. This has the advantage that the drainage pipe 22 does not need to be cut, but instead the level sensor 10 can be arranged on the outside of the existing drainage pipe 22.

[0047] In order to retrofit a conventional air extraction element with the sensor drainage unit 100, 102, 104 according to the invention, the level sensor 10 can thus, for example, be arranged inside a drainage pipe element 20 that can be integrated into the existing drainage pipe 22, or be arranged directly outside a drainage pipe element 20 that can be integrated into the existing drainage pipe 22, or be designed to be arranged directly outside the existing drainage pipe 22.

[0048] The sensor drainage unit 100, 102, 104 thus retains the function of the drainage pipe 22. In addition, the sensor drainage unit 100, 102, 104 also enables access to the drainage oil at the bottom of the filter insert 120 of the air de-oiling element 200, 202 by means of a non-contact level sensor 10.

[0049] The sensor drainage unit 100, 102, 104 can be enclosed in a housing, for example an aluminum housing 50. This aluminum housing is advantageously designed to be integrated into the drainage pipe 22, for example by being screwed between pipe elements of the drainage pipe 22.

[0050] The sensor drainage unit 100, 102, 104 according to the invention can also be integrated into the drainage line of a new air de-oiling element 200, 202 at the factory during initial installation. An optimized drainage line could also be supplied as a unit with the aluminum housing 50 in the original equipment manufacturer (OEM) business. In the case of a retrofit (OES), however, the existing drainage line can be used.

[0051] The level sensor 10 is designed for contactless or non-contact measurement of the level of the oil separated by coalescence and accumulating in the oil collection area 140. The level sensor 10 can be designed, for example, as a laser sensor, an ultrasonic sensor, or an electromagnetic level sensor.

[0052] A level sensor 10 not designed as a rod probe according to the invention is in the Fig. 3, Fig. 11 and Fig. 13 shown. In Fig. Figure 3 shows a section of wall 126 of the pressure storage tank 110, through which the drainage pipe element 20 passes. The rod probe 10 can, for example, be screwed into the drainage pipe element 20.

[0053] The liquid level of the drainage oil in the air extraction element 200, 202 can be directly detected by means of the level gauge 10. The measured level can be further processed, for example as an electrical signal. In this way, a valve 30, designed to control the drainage volume of the drainage pipe element 20, can be actuated with a signal that depends on the measured level.

[0054] This valve 30 can, for example, be configured to open the drainage pipe element 20, 22 when a maximum fill level 142 of the oil collection area 140 is reached. Furthermore, the valve 30 can be configured to close the drainage pipe element 20, 22 when a minimum fill level 144 of the oil collection area 140 is reached, or when the maximum fill level 142 of the oil collection area 140 has not yet been reached.

[0055] The aluminium housing 150 can also serve as a mount for the measuring system, in particular for the level gauge.

[0056] The level gauge 10 can be designed to measure other interesting values ​​such as temperature, pressure, original part yes / no, etc., via the drainage pipe element 20, 22 from the pressure storage tank 110 and transmit them to an electronic processing unit.

[0057] The sensor drainage unit 100, 102, 104 according to the invention also opens up the possibility of providing a complete solution, for example a kit with aluminium housing 50, control valve 30 and sensor 10, suitable for the respective air de-oiling element 200, 202, wherein the drainage line 20, 22 could already be permanently installed with the flange 124 of the air de-oiling element 200, 202 and the aluminium housing 50 is only attached or screwed on after the pressure accumulator lid 118 has been closed.

[0058] Furthermore, the installation of at least one additional separate sensor (not shown) is also possible with a separate bore through the cover 118 or through the housing 124 of the pressure storage tank 110. These sensors can be evaluated in addition to the other data.

[0059] As is known from the prior art, the operating pressure of the air-oil separator 200, 202 can be measured on the raw side of the air-oil separator 200, 202. Using the sensor drainage unit 100, 102, 104, a pressure sensor can also be provided on the clean side, which would make it possible to measure the differential pressure of the air-oil separator 200, 202 online and to estimate the possible service life of the air-oil separator 200, 202.

[0060] The Fig. Figures 6 to 9 show a compressed air system 400 comprising a compressor 300, an air oil removal element 200, 202 and a drainage pipe (element) 20, 22 with a drainage quantity control device 100, 102, 104, 106.

[0061] The compressed air system 400 has three filters, namely - an air filter 310 to clean the incoming air - the air oil removal element 200, 202 for oil removal from oil-laden compressed air of the compressor 300 and - an oil filter 350 for cleaning the lubricating oil designed to lubricate the compressor 300.

[0062] The air-oil removal element 200, 202 is connected to an aftercooler 320 and the aftercooler 320 to a water separation element 330.

[0063] Pre-separated oil from the oil collection volume 150 at the bottom of the pressure storage tank 110 is routed via the liquid outlet 112 to the oil filter 350, then to an oil cooler 340 and then back to the pressure stage or to the compressor screw 300.

[0064] The oil separated by the filter element 120 via coalescence is returned directly or indirectly to the compressor screw 300 via the drainage pipe 20, 22. The return flow of the drainage to the compressor screw 300 is in the Fig. 6 to 9 are designed differently.

[0065] At the in Fig. In the compressed air system 400 shown in Figure 6, the oil separated by coalescence is returned directly from the drainage pipe 20, 22 to the compressor screw 300. In the Fig. In the compressed air system 400 shown in section 7, the drained oil is returned to the compressor screw 300 via an intermediate tank 360 and a pump 370. In the case described in Fig. In the compressed air system 400 shown in Figure 8, the drained oil is returned to the compressor screw 300 via an intermediate tank 360. Fig. Figure 9 shows a compressed air system 400, in which the drained oil is fed back to the raw side of the pressure-resistant container 110 via an intermediate tank 360 and a pump 370 and then runs from there back to the compressor screw 300.

[0066] The present invention makes it possible to significantly reduce the amount of drainage, whereby the drainage line can be selectively closed and opened depending on the amount of drainage oil that accumulates under the respective operating conditions of the compressor and how full the reservoir in the air vent element bottom cover is.

[0067] The invention describes a simple way to access data from the pressure storage tank 110 via the drainage pipe 20, 22. The sensor drainage unit 100, 102, 104 can be integrated into an existing drainage pipe without requiring any mechanical modification or alteration. Furthermore, no antennas or transmitters are required for data transmission. Reference symbol list 10 Level measuring devices, in particular liquid sensors, for example laser measuring units, for non-contact or non-touching measurement of the fill level or level of liquid accumulating in a pressure-resistant container 110, in particular oil 12 electrical connection (see Fig. 3) 20 Drainage pipe element or drainage line element associated with sensor drainage unit 100; 102; 104 for draining the liquid from the pressure-resistant container 110, in particular for returning the liquid separated in the pressure-resistant container 110 to the pressure stage or to the sump of the connection component 22 additional drainage pipe element or drainage conduit element 30 Valve designed to control the drainage quantity of the drainage pipe element 20 50 housings, for example aluminum housings, for the sensor drainage unit 100; 102; 104 100 Sensor drainage unit, in particular drainage quantity control device, first embodiment see. Fig. 1, Fig. 4, Fig. 5, 102 Sensor drainage unit, in particular drainage quantity control device, second embodiment see. Fig. 2, Fig. 6, Fig. 7, Fig. 8, Fig. 9, Fig. 10 and Fig. 12 104 Sensor drainage unit, in particular drainage quantity control device, third embodiment see. Fig. 3, Fig. 11 and Fig. 13 110 pressure-resistant container or pressure vessel or pressure storage container 112 Liquid outlet designed for releasing the liquid accumulating in the pressure-resistant container 110 114 Raw air inlet for introducing raw air, originating from the connection component 300 and loaded with liquid, into the pressure-resistant container 110 116 Clean air outlet, in particular clean air outlet pipe, for releasing the compressed air cleaned by the filter element 120 118 Cover of the pressure-resistant container 110, housing cover or pressure vessel cover or pressure storage container cover, in particular housing nozzle 120 filter inserts (see below) Fig. 4) 122 Separation element designed for separating oil and oil aerosol from air in the form of a cylindrical coalescer, in particular made of glass fiber and / or plastic, for example of nonwoven fabric, 124 Flange, in particular end plate, of the filter element 120, for mounting the filter element 120 between the cover 118 and the housing body 126 of the pressure-resistant container 110 126 cylindrical, pressure-resistant housing body or pressure vessel base or pressure storage vessel base of the pressure-resistant container 110 128 Support tube for supporting the separating element 122 130 axial end plate for covering the axial end face of the separating element 122 facing away from the flange 124, in particular a foot-side end plate or foot-side end cap or bottom element for covering the hollow cylindrical foot side of the filter insert 120 140 Liquid collection area, in particular oil collection area, which is assigned to the axial end disk 130, is arranged radially within the separating element 122 and is designed to collect the liquid separated by the separating element 122 (see Fig. 1, Fig. 4 and Fig. 5) 142 Maximum fill level of the liquid collection area 140 144 minimum fill level of the liquid collection area 140 150 Liquid collection volume, in particular oil collection volume or oil collection chamber, for collecting liquid separated by pre-separation, in particular by gravity and / or by centrifugal force during tangential inflow of raw air into the housing body 310 (cf. Fig. 1 and Fig. 5) 200 liquid separators, in particular compressed air dehumidifiers, for example air oil removal elements, first embodiment see. Fig. 1 202 Liquid separator, in particular compressed air dehumidifier, for example air oil removal element, second embodiment see. Fig. 5 and Fig. 9 300 Connection component, in particular oil-lubricated compressor element or oil-lubricated vacuum pump element, for example compressor screw 310 Air filters of the compressed air system 400 320 aftercoolers 330 Water separation 340 oil cooler 350 oil filters 360 tank or intermediate tank 370 pump 400 Compressed air system, in particular compressor or vacuum pump

Claims

[1] Liquid separator (200; 202) for separating oil and / or oil aerosol from compressed air, wherein the liquid separator (200; 202) has a cylindrical pressure-resistant container (110) with a raw air inlet (114), in particular arranged radially, wherein the raw air inlet (114) is connectable to a connection component (300) in the form of a compressor element, and wherein the raw air inlet (114) is configured to admit compressed air containing liquid from the connection component (300) into the pressure-resistant container (110), and wherein a filter insert (120) with at least one separating element (122) configured as an annular coalescer is arranged in the pressure-resistant container (110), wherein the separating element (122) is designed to separate oil and / or oil aerosol from the liquid-containing compressed air is formed characterized by a sensor drainage unit (100; 102; 104) comprising the sensor drainage unit - at least one drainage pipe element (20, 22) for draining oil that collects in the filter insert (120) of the liquid separator (200; 202), which is designed to return the oil separated by coalescence from the filter insert (120) directly or indirectly to the compressor element and - at least one level sensor (10) designed for contactless measurement of the level of the oil accumulating in the filter insert (120) and designed to supply at least one valve (30) with at least one signal dependent on the measured level, wherein the level sensor (10) is associated with the drainage pipe element (20; 22) and is arranged either inside the drainage pipe element (20; 22) or directly outside the drainage pipe element (20; 22). [2] Liquid separator according to claim 1, characterized bya valve (30) which is switched depending on the fill level measured by the level gauge (10), wherein the valve (30) controls the drainage quantity of the drainage pipe element (20, 22). [3] Liquid separator according to at least one of the preceding claims, characterized by , that the pressure-resistant container (110) has a lid (118) designed to close its end face, wherein the lid (118) of the pressure-resistant container (110) has a clean air outlet (116) on the clean side, in particular arranged axially, for releasing the compressed air cleaned by the filter insert (120), and wherein, for returning the clean air cleaned by the filter insert (120), the clean air outlet (116) can be connected to the connection component (300). [4] Liquid separator according to claim 3, characterized byan axial end disk (130) for covering the axial end face of the separating element (122) of the filter insert (120) facing away from the lid (118), wherein the axial end disk (130) has a liquid collection area (140) arranged radially inside the separating element (122) for collecting the liquid separated by the separating element (122) and wherein the drainage pipe element (20) projects into the separating element (122) up to the liquid collection area (140). [5] Liquid separator according to claim 3 or 4, characterized by , that the filter element (120) is arranged replaceably in the pressure-resistant container (110) and the lid (118) of the pressure-resistant container (110) is removable, in particular screwable, wherein the filter element (120) has a flange (124) arranged at its end face, which (124) can be clamped between the lid (118) of the pressure-resistant container (110) and the cylindrical body of the pressure-resistant container (110). [6] Liquid separator according to any of the preceding claims, characterized by , that the level gauge (10) measures the level of the liquid collecting in the pressure-resistant container (110) by means of a laser or by means of ultrasound.

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