DE102006048078A1 - Plant for purifying liquid, e.g. lubricating oil for machine, includes liquid purifier and separator with outlet connected to collection and distribution vessel, allowing recycling of liquid - Google Patents

Abstract

A plant for cleaning liquids, in particular oil from a machine (30), with a liquid container (22) which collects the liquid and supplies the machine with the liquid, with a separating container (2) for separating the machine and discharged to cleaning liquid in at least two components, wherein the separating container, a feed device (4), via which the liquid to be purified is introduced into the separating container, and a first discharge means (8) for discharging a first component of the liquid and a discharge device (12) for discharging a second component of the liquid. According to the invention, the discharge device (12) of this separation container (2) is in fluid communication with the liquid container (22), so that liquid discharged from the separation container can be supplied to the liquid container (22).

Description

Field of the invention

The The present invention relates to a device for cleaning of oil and in particular for cleaning oil, which is used for the lubrication of Equipment or machinery is used and with other liquids how water is contaminated. In the prior art, it is common that For machines that use oil for lubrication, this oil is common collected with water residues and fed to a phase separator becomes. This phase separator separates the water from the oil and carries that separated oil subsequently a waste oil container or the final Disposal too.

Besides Such machines sometimes have day oil containers for permanent oil supply serve the machines. Due to the oil consumption these must Day oil tank, however with significant amounts of fresh oil be supplied, for example, 1500 l per week quite usual values are. This need, oil in high quantities, has a cost-increasing effect on the overall operation of the machine. The present invention is therefore the object of a Device available to ask what the need for fresh oil and therefore the cost of operation reduced the machine.

With In other words, in a plant or machine accumulating mixture from cooling water and lubricating oil be separated, the cooling water the cooling water circuit supplied become and the dirty oil be cleaned and fed to the machine. This is inventively An installation according to claim 1, an apparatus according to claim 7 and a method according to claim 15 achieved. Advantageous embodiments and further developments are the subject of the dependent claims.

The inventive plant for cleaning fluid and especially of oil a machine has a fluid container, which the liquid collects and supplies the machine with the oil. Furthermore, a separation container for disconnecting the machine dispensed and cleaned liquid provided in at least two components, wherein the separation container a feeding has, over which the liquid to be purified in the separation container introduced becomes. Furthermore, a first discharge device is provided to a first component of the liquid drain, and an evacuation device, to remove a second component of the liquid. According to the invention the discharge device of the separation vessel in fluid communication with the liquid container, with it from the separation container dissipated liquid be supplied to the liquid container can.

at the liquid container acts in particular it concerns the above-mentioned day oil container, which preferably in continuous oil circulation with the machine stands. A separation container is understood to be a container, in which a liquid into different components and in particular into different ones Phases can be separated. Such a separation can for example between oil and water take place.

Under a feeder Any device is used, with the separation of the liquid supplied can be. Also, for example, provided in the separation container wall, which the separation container divides into two rooms, is used as a feeder considered within the meaning of the invention. Preferably, however, it is at the feeder around a feed pipe.

at the first component of the liquid in particular, water or oil highly contaminated with water, which a final one Disposal supplied becomes. The second component of the liquid is in particular to not or only slightly contaminated with water which oil again the liquid container and thus fed to the machine becomes.

Thereby, that the discharge device of the separation vessel in fluid communication stands with the liquid container and so on the separation container dissipated liquid be supplied to the liquid container can, it is possible, in contrast to the prior art, oil, which otherwise would be disposed of return to the machine cycle. In this way, as mentioned above the need for fresh oil be greatly reduced.

Under a flow connection therefore every execution understood that transporting a medium from a first flow-connected Device for the or another flow-connected device allows. This transport can also indirectly, d. H. about more Facilities, done.

Preferably, a first cleaning device for cleaning the liquid or the further constituent of the liquid is arranged between the separation container and the liquid container. This may, however, in particular but not exclusively be a filter that filters impurities out of the oil. The separation container has a much larger volume for the liquid compared to known in the art phase separators. The volume may be, for example, in the range of 3000 l. On the In this way, essentially continuous removal of the second constituent of the liquid is possible. This will be explained in detail below.

at a further embodiment has the liquid container a Outflow and an inflow, with the outflow and the inflow over each other a flow circuit in fluid communication stand. This is by this outflow and inflow a closed Cycle for to be cleaned oil educated. This closed circuit is in particular independent of the circuit that supplies the machine with oil. Preferably in the flow circuit a filter means provided to clean the oil flowing through this circuit. In a further advantageous embodiment is in this cycle also a pump for conveying of the oil in the flow circuit intended. Preferably, the flow circuit has a connection for the from the discharge device guided liquid on. This is the flow circuit in conjunction with the above-described cycle or above described flow connection, the with the liquid container the separation container combines. Particularly preferably flows the connection in a subsequent to the discharge device line.

Prefers is in the flow circuit one Heating device for the liquid intended. Dependent on from the oil viscosity is a Heating up the oil meaningful. Warm low-viscosity oil favors the Cleaning and the residual water settles better. The heating takes place preferably over an electric circulation heating. This heater advantageously has a Thermostats on, a safety thermostat and a pressure relief valve. In addition, the heater can also with a temperature monitoring indicator (For example, PT 100) and an automatic venting provided be.

The Heating may be used in other embodiments dependent from the local and system-related events also in the liquid container and / or the separation container be performed. In addition to an electric heater, it is also possible to Heating effect with other energy sources to achieve, for example, with warm steam or waste heat from the production.

at a further advantageous embodiment is between the Fluid container and the machine provided a means for cooling the liquid or the oil. Because, as mentioned above, the oil in one embodiment is heated, it may be necessary under certain operating conditions the oil to cool again, overheat levels in the Machine to avoid.

The The present invention is further directed to a device for cleaning of liquids and especially of oil for one Plant of the type described above. This device has a separation container for separating the liquid to be purified into at least two Ingredients on. Furthermore, a feed device is provided, via which the liquid to be cleaned in the separation container introduced becomes. Furthermore, a first discharge device for draining a first component of the liquid and a discharge device for discharging a second component of the liquid provided.

According to the invention Discharge device in a bottom region of the separation container arranged, the discharge device provided above the discharge device and the feed device protrudes in a lower portion of the separation container. In this feeder it is, as shown above, for example, a feed tube, it However, also a partition within the separation container be provided, this partition the container in two in the lower section of the separation vessel shares connected subspaces and in one subspace the oil a filled becomes. Due to the fact that the feeder protrudes into a lower portion of the separation tank, can contamination be separated more easily. Also, in this way, the phase separation between oil and Water accelerates.

Preferably a pump is provided on or after the drainage device, around the first component of the liquid, d. H. in particular to suck off the contaminated with water content. It is also advantageous at the discharge device a Pump provided to reuse the oil from an upper area of the separation vessel suck. The separation container points opposite usual Phase separators a much larger volume in order to achieve in this way a continuous discharge of the oil. More precisely allows it's the high capacity, that within the separation container several liquid phases are formed, for example, an upper phase, which are dissipated can, a middle phase, in which a separation between the constituents takes place permanently and in the following also as a calming zone is designated and a lower zone, in which predominantly dirt and water and which over the discharge device can be drained.

In other words, the separation container has a predetermined height and the discharge device is arranged on an upper portion of this separation container. In this case, the upper section of the separation container is an upper quarter, preferably an upper fifth, more preferably an upper seventh and more preferably a upper tenth of the separation vessel. This means that in each case only liquid from this upper region and thus liquid with a very high oil content is removed from the separation container.

In a further preferred embodiment is in the separation tank a sensor device for determining a water content of the to be cleaned liquid arranged. In dependence of a measured value that this sensor device outputs can be decided be over the discharge device liquid is discharged and if necessary in what quantity. Instead of a Sensor device would be but it is also possible to determine the water content in each case by calculation and in given intervals each liquid over the Discharge device to drain. It would also be possible for the sensor device is only designed as a control device and not for regulation or control of a discharge valve arranged in the discharge device.

In order to in particular, the separation container, the can also be referred to as Absetzank, be designed as large as possible so that the from a pre-connected phase separator in the feeder incoming oil preferably long in the separation container remains and separates from the residual water. This residual water can, as mentioned above, in common with any deposited dirt particles on the discharge if necessary with Help of a pump and controlled by the residual water detection or sensor device are pumped. This sensor device is in itself known from the prior art and works after a microwave principle.

Preferably is the sensor device for determining the water content in the lowest third, preferably in the lowest quarter and especially preferably provided in the lowest sixth of the separation vessel. As mentioned serves the sensor device for determining the residual water and for deciding whether over the draining device should be drained. That's why it's special Preferably, this sensor device in the lower and thus richest in residual water Area of the separation container provided.

Especially Preferably, the feed tube protrudes in the bottom third, preferably in the bottom fifth, especially preferably in the lowest sixth and more preferably in the lowest tenth of the separation vessel.

In a further preferred embodiment is a first cleaning device for cleaning of the over removal device dissipated Component of the liquid intended. In this dissipated Stand part of the liquid there are still soiling caused by the first cleaning equipment, which is, for example, a filter, filtered out can be.

Prefers the first cleaning device is a second cleaning device downstream. This second cleaning device has, for example a finer filter to also weed out such particles, which were not detected in the first cleaning device. at a further preferred embodiment can also be electrostatic between the two cleaning devices Device or particle connection device be provided the one joining smaller protective particles and thus causes their enlargement.

The The present invention is further directed to a method of cleaning of liquids and especially of oil directed. In this case, in a first process step, the oil in a Separation container supplied, wherein the oil the separating container over a feeding supplied is, which preferably projects into a lower region of the separation vessel. Furthermore, a first component of the liquid is discharged via a first discharge device drained and a second component of the liquid via a discharge device dissipated.

According to the invention second component substantially continuously removed from the separation vessel. at Phase separations according to the prior art, usually deposited in a single process step, the oil phase. This is sufficiently so, as this phase does not continue to exploit, but is disposed of directly. According to the invention, a continuous Process proposed which makes it possible that oil in a higher purity, d. H. with significantly lower water contamination continuously dissipated becomes. For example, it is possible that in a separating container, which is a capacity in the range of 3500 l, only the 120 l, located in the upper Area of the separation container are located, discharged become.

In order to preferably has the separation container given volume for the liquid on and daily is a proportion of less than one-tenth, preferably less as a fifteenth and more preferably less than one-fifth of that volume over the removal device dissipated.

In a further advantageous method, the liquid discharged from the discharge device is supplied to a liquid container. This liquid container is again the daily oil container mentioned above. Advantageously, a flow circuit is provided, wherein The oil is removed from this day oil tank, cleaned and stirred again to the day container. This oil removed from the liquid container and the oil originating from the discharge device are supplied in a particularly advantageous manner. Thus, a cleaning of the oil in the liquid container is performed permanently in the above-mentioned flow circuit. Thus, the oil in the liquid container may have a higher degree of purity than the fresh oil which is supplied in the prior art. Particularly preferably, oil is transported from the separating container to the liquid container via a flow connection.

Preferably becomes that of the evacuation device dissipated liquid cleaned, in which case the above-mentioned cleaning facilities be used. Preferably, the liquid container becomes liquid dissipated and returned to the liquid container in a closed circuit. Especially is preferred by the discharge device not discharged oil more of a fresh oil reservoir supplied to prevent the risk of contamination of the fresh oil.

Further Advantages and embodiments emerge from the attached Drawings:

In this demonstrate:

1 an oil circuit according to the prior art;

2 a plant according to the invention; and

3 an inventive separation container.

1 shows a plant 1 According to the state of the art. There is a machine 30 provided, the oil requirement of a day oil container or a liquid container 22 is covered. For this purpose, in a circuit from the liquid container clean oil into the machine by means of a pump 41 Pumped and returned in the return oil back into the liquid container 22 , During operation of the machine, for example, 70 l per hour can circulate. At the same time, dirty oil or water contaminated with water is produced in the machine. This liquid enters a collection container 39 , and becomes a phase separator from there 34 promoted. In this phase separator 34 the oil phase and the water phase are separated from each other and the oil phase passes into a waste oil container 44 from which the waste oil turn with a pump 48 can be pumped out. Since thus the entire cycle oil is lost, the liquid container must 22 via an oil supply 45 be refilled. In the present example, about 1500. per week must be refilled, which represents a significant cost factor.

In order to was the task of the invention also in it, a resulting cooling water / lubricating oil mixture to separate the cooling water Cooling water circuit feed again and the polluted oil to clean and return to the machine.

2 shows a plant according to the invention for cleaning liquids and in particular oil. In this case, the reference numeral refers 30 in turn to the machine, derived from the polluted or water-contaminated oil and to the phase separator 34 is directed. This phase separator separates oil from water in a first step. At the in 2 The embodiment shown has been the phase separator with an automatic sludge 35 retrofitted. The reference number 37 refers to a device for cleaning filter components of the phase separator 34 , This cleaning can be done with compressed air. The cleaned residual contaminants are finally in a discharge reservoir or a sump 11 disposed of.

That in the phase separator 34 separated oil passes through a feeder 4 in the separation container 2 , This is polluted oil from the phase separator, which may contain, for example, 92% oil and 8% water. This oil is delivered via the feeder 4 in a lower region of the separation container 2 fed. Unlike the phase separator 34 is the separation container 2 designed so that the polluted oil lingers within the same as long as possible.

In a lower or bottom area 2a the separation container has a discharge device 8th on to drain dirt particles and residual water. In this case, this discharge process by a pump 9 supported. The reference number 5 refers to a sensor device for determining the water content. Depending on the values output by this sensor device, it is possible to control whether via the discharge device 8th is drained. The reference number 12 refers to a discharge device for removing oil from the separation container 2 ,

The reference number 13 refers to a second pump, the oil directly through the cleaning devices described below in detail to the machine 30 pumps it back. This pump 13 is determined by (not shown) probes depending on the level of the level of oil inside the separation vessel 2 controlled. This probe (not shown) is inside the separation vessel 2 or tanks installed as high as possible, as long as possible Settling time of dirt particles and water to achieve. The switching range of this probe is designed so that as often as possible small amounts of oil cleaned are fed to the machine. If the probe is released or the state level drops, the pump switches 13 off and at the same time the third pump 23 which supports a cycle described in more detail below.

The third pump 23 pumps this at the machine and in the liquid container or daily oil container 22 existing oil in the remaining time, ie in the time in which the pump 13 is switched off, in the (also referred to as flow circuit above) side stream permanently through the cleaning facilities 16 . 18 . 20 , In this way it is achieved that the oil in the liquid container 22 gets cleaner as that of the central oil supply 36 added fresh oil. This secondary circuit or flow circuit has three supply lines 27 . 28 and 29 on and between these leads are a heater 14 as well as the cleaning facilities 16 - 20 intended.

The reference number 24 denotes a drain and the reference numeral 26 an inflow of the liquid container 22 ,

The reference number 14 refers to a heater for heating the oil, since, as mentioned above, depending on the oil viscosity, heating of the oil makes sense. Downstream of the heater are a first cleaning device 16 and a second cleaning device 20 , These are filters which are self-cleaning with foreign medium. The cleaning devices or filters used 16 . 20 have differential pressure switch for monitoring. Upon reaching a set differential pressure, a cleaning of the filter is effected automatically. The cleaning time is adjustable. For cleaning, compressed air is used, which pushes dirt particles out of the respective filter components so that the filters can be reused.

The two cleaning facilities 16 . 20 or filters have different filter widths. Preferably, the first cleaning device has a higher filter width than the second cleaning device in order to achieve an increasing degree of cleaning. At the in 2 the embodiments shown, the filter width of the first cleaning device 20μ and the filter width of the second cleaning device 20 10μ. However, these filter lengths can be changed depending on the application. The reference numerals 16a and 20a refer to the respective device for cleaning the filter, ie on working with compressed air devices and the reference numerals 16b and 20b on aeration.

Between the first cleaning device 16 and the second cleaning device 20 is a particle connection device 18 intended. The object of this device is the small dirt particles, which are the first cleaning device 16 flow through, join together so that they become larger particles and so that the larger particles in the second cleaning device or even the next flow through the flow circuit 27 . 28 . 29 be withheld.

In the particle connection device 18 the oil is divided into two subsets and a first subset is charged positively and a second subset negatively. It should be noted that not the oil itself but the dirt particles are charged. Since uneven charges attract, the dirt particles stick to each other, thereby becoming larger and in the cleaning device 20 retained.

Smaller charged particles, however, flow through the filters, thus getting to the machine 30 and dissolve oppositely charged particles. To ensure this, the polarity in the particle connection device changes 18 constantly. In this way, the entire lubrication system of the machine is cleaned. The particle connection device 18 was doing with an automatic venting 18b and a cleaning 18a retrofitted.

The individual dirt particles coming from the filters of the cleaning device 16 and 20 as well as from the particle connection device 18 are removed, as shown in detail, also in the Ablassreservoir 11 , Optionally, downstream of the second cleaning device could be 20 a so-called coalescer be inserted. If the residual water content after the second cleaning device 20 exceeds a certain value x, it is possible to after the second cleaning device 20 to provide the said coalescer.

A another possibility would also in it, the fresh oil content to increase, until the water content reduces again below a certain level Has.

Reference symbol I relates in FIG 1 on the tank side and the reference II on the machine side. In contrast to the prior art, in the system described here, therefore, oil is permanently being removed through the cleaning devices 16 . 18 and 20 cleaned and that means that it is oil from the circulation fluid container 22 or oil, which is from the separation vessel 2 comes. To save heating energy be be preferably both the liquid container 22 and the separation container 2 provided with insulation as well as the individual lines such as the lines 27 . 28 . 29 , The reference number 32 refers to a cooler for cooling the oil returning to the machine. The reference number 38 denotes a pump for pumping the oil from the liquid container 22 into the machine 30 , In the oil cooler 32 In this case, pressures in the range of 60 bar can occur.

Furthermore, between the liquid container 22 and the machine 30 even more filters (not shown) may be provided.

To control the system, a control program with a touch panel is used. Oil cleaning is monitored on the oil side and on the compressed air side with pressure switches. In this case, the actuation of the respective actuators takes place here electropneumatically and the movements of the actuators are monitored. To avoid a mixture of used oil with fresh oil, the two pumps are 13 and 23 electrically locked and fitted with check valves. All malfunctions or faults are displayed and cause the system to be switched off. However, regardless of the function of oil cleaning, the machine will continue to be supplied by the central oil supply 36 supplied with fresh oil.

3 shows a schematic representation of a separation container 2 , This separation container 2 has in the embodiment shown here a height of 3m and a capacity of about 3600 l. As mentioned above, the contaminated oil passes along the arrow P1 in the feeder 4 and is in this way in a lower area of the separation vessel 2 promoted. In contrast to the usual phase separations a very long time is ensured in the dirt particles and water in the liquid mixture in the container 2 can settle.

This can be within the separation container 2 train several zones. An upper zone A contains the oil that is largely free of water and dirt. This oil is via the discharge device 12 the in 2 supplied cleaning process shown. The reference B refers to a calming zone. This zone is by far the largest in the embodiment shown here and comprises a volume of about 3200 l. In this area, oil and dirt particles can settle. The reference character C denotes the volume which is heavily contaminated with water and dirt particles and the discharge means 8th is derived. The newly added oil is in a lower area of the separation vessel 2 directed, so that the oil, which is located in the upper region A, no longer contaminated or polluted. The feeder ends at a height h1 of about 40-50 cm above the bottom of the separation container. In the upper area is a probe 6 provided, which controls the level. As soon as the level drops below the area A, the in 2 shown pump 13 switched off. In the upper area can be found at the in 3 embodiment executed about 120 l. Furthermore, a probe is provided which has a maximum level within the separation container 2 or exceeding this maximum level indicated to overflow the separation vessel 2 to prevent. From area A, oil is preferably pumped off continuously.

All Features disclosed in the application documents are considered to be essential to the invention as long as they are individually or in combination with respect to State of the art are new.

1

investment for cleaning liquids

2

separation container

2a

floor area of the separation vessel

4

feeding

5

sensor device for determining the water content

6

probe

8th

discharge device

9

pump for deflation device

11

drain reservoir

12

removal device

13

pump

14

heater

16

first cleaning device

16a, 20a

contraption for cleaning

16b 20b

ventilation

18

Particles connecting device

18a

cleaning the particle connection device

18b

automatic vent the particle connection device

20

second cleaning device

22

A liquid containment

23

pump for liquid container

24

Outflow of the liquid container

26

inflow of the liquid container

27 28, 29

cables

30

machine

32

cooling device

33

collecting container

34

phase separator

35

automatic Sludge of the phase separator

36

supply reservoir for fresh oil

37

contraption for cleaning

38

pump

39

collecting container

41

pump

44

oil container

45

oil supply

48

pump

A, B, C

Areas of the separation container 2

H

Height of the separation container

h1

Distance of the feeder from the bottom of the separation container 1

Claims (18)

Plant for cleaning liquids and in particular oil from a machine ( 30 ), with a liquid container ( 22 ), which collects the liquid and supplies the machine with the liquid, with a separation container ( 2 ) for separating the liquid discharged from the machine into at least two components, the separating container ( 2 ) a feeder ( 4 ), via which the liquid to be purified is introduced into the separating container, and a first discharge device ( 8th ) for discharging a first constituent of the liquid and a discharge device ( 12 ) for discharging a second constituent of the liquid, characterized in that the evacuation means ( 12 ) of the separating container ( 2 ) in fluid communication with the fluid container ( 22 ), so that liquid discharged from the separation container is in the liquid container ( 22 ) can be supplied. Plant according to claim 1, characterized in that between the separation container ( 2 ) and the liquid container ( 22 ) a first cleaning device for cleaning the liquid is arranged. Plant according to at least one of the preceding claims, characterized in that the liquid container has a drain ( 24 ) and an inflow ( 26 ), the outflow ( 24 ) and the inflow ( 26 ) with each other via a flow circuit ( 27 . 28 . 29 ) are in fluid communication. Plant according to claim 3, characterized in that the flow circuit ( 27 . 28 . 29 ) a connection for the of the discharge device ( 12 ) has discharged liquid. Plant according to at least one of the preceding claims 3-4, characterized in that in the flow circuit ( 27 . 28 . 29 ) a heating device ( 14 ) is provided for the liquid. Plant according to at least one of the preceding Claims, characterized in that between the liquid container and the machine is provided with means for cooling the liquid. Contraption ( 1 ) for cleaning liquids and in particular oil for a plant according to at least one of the preceding claims 1-6, with a separating container ( 2 ) for separating the liquid to be purified into at least two components, a feed device ( 4 ), via which the liquid to be purified in the separation container ( 2 ), a first discharge device ( 8th ) for discharging a first constituent of the liquid and a discharge device ( 12 ) for discharging a second component of the liquid, characterized in that the discharge device ( 8th ) in a ground area ( 2a ) of the separation container is arranged, the discharge device ( 12 ) is provided above the discharge device and the feed device ( 4 ) in a lower portion of the separation container ( 2 protrudes. Device according to claim 1, characterized in that the separating container ( 2 ) has a predetermined height (H) and the discharge device ( 12 ) in an upper section of the separation container ( 2 ) is arranged. Device according to at least one of the preceding claims, characterized in that in the separation container ( 2 ) a sensor device ( 5 ) is arranged to determine a water content of the liquid to be purified. Device according to at least one of the preceding claims, characterized in that the feeding device ( 4 ) in the lowermost third, preferably in the lowest fifth and particularly preferably in the lowest sixth of the separating container ( 2 protrudes. Device according to at least one of the preceding claims, characterized in that a first cleaning device ( 16 ) for cleaning of the via the discharge device ( 12 ) discharged component of the liquid is provided. Apparatus according to claim 7, characterized in that the first cleaning device ( 16 ) a second cleaning device ( 20 ) is subordinate. Process for the purification of liquids, and in particular of oil, comprising the steps of: - supplying the liquid into a separating container ( 2 ), wherein the liquid is the separation container ( 2 ) via a feeder ( 4 ), which preferably in a lower region of the separation container ( 2 protrudes; Draining of a first constituent of the liquid via a first discharge device ( 8th ); - Removal of a second component of the liquid via a removal device provided on the separation device ( 12 ), characterized in that the second component substantially continuously from the separation container ( 2 ) is discharged. A method according to claim 15, characterized in that the separation container ( 2 ) has a predetermined volume for the liquid and a daily proportion of less than 1/10, preferably less than 1/15 and particularly preferably less than 1/25 of this volume via the discharge device ( 12 ) is discharged. A method according to claim 16, characterized in that the of the discharge device ( 12 ) discharged liquid a liquid container ( 22 ) is supplied. A method according to claim 15, characterized in that the from the discharge device ( 12 ) cleaned liquid is cleaned. Method according to at least one of the preceding claims, characterized in that from the liquid container ( 22 ) Liquid is discharged and via a closed circuit ( 27 . 28 . 29 ) is returned to the liquid container. Method according to claim 19, characterized in that in the circuit ( 27 . 28 . 29 ) at least in sections also liquid from the discharge device ( 12 ) to be led.