Device for separating fluid mixtures

Abstract

The invention relates to a device for separating fluid mixtures, in particular for separating water from oil, comprising a vacuum container (10) with several sub-chambers (26, 44, 40). According to the invention, at least one liquid constituent of the fluid mixture can be transported from the vacuum container after separation, by means of a transport device (12) and the other constituents can be extracted from the vacuum container (10) in the form of gas and/or steam, using a vacuum pump (20). One of the sub-chambers (26) of the vacuum container (10) houses a heating device (28, 30), which heats the fluid mixture, the latter being guided into an additional sub-chamber (40) and being separated into its constituents by traversing a packed bed. The invention therefore allows even cold and consequently viscous fluid mixtures to be supplied, by means of the heating device, for separation inside the aforementioned vacuum container.

Description

[0001] The invention relates to a device for separating fluid mixtures, in particular for separating water from oil, comprising a vacuum tank with several sub-chambers, and at least one liquid component of the fluid mixture can be transported out of the vacuum tank after separation by a delivery means and the corresponding other components can be extracted from the vacuum tank in gas and/or vapor form by means of a vacuum pump.

[0002] In a non-generic device for separating an oil/water mixture as claimed in EP 0 148 444 A2 there is a pre-separation space in which first the coarser components of the oil are separated from the mixture. The mixture which has been precleaned in this way is then delivered to a coalescence chamber which contains a plurality of coalescing bodies which consist of an oleophilic plastic and are lighter than water. Extremely fine oil particles also settle on the oleophilic, specifically large surface of these body, flow together on the bodies and rise as larger, easily separable oil droplets into the separation space where they can collect and can be removed in the oil collection space. The water flows out of the separation space by way of a partition through another pipe. The known device is large and although oil separation is maintenance-free with the device over a longer time interval, the oleophilic coalescence bodies from time to time must be replaced by new ones; this leads to downtimes of the system. With respect to the size of the system, the discharge performance on the oil and water which have been separated from one another is relatively low. Especially under cold ambient conditions and for moreover cold fluid mixtures to be separated the water removal performance, especially the rate with which water removal takes place, is insufficient.

[0003] EP 0 733 389 B1 discloses a generic device for separating fluid mixtures, especially of oil and water, with a vacuum tank in which this fluid mixture can be atomized by means of an atomization means, and at least one liquid component of the fluid mixture after its separation can be drained from the vacuum tank and the corresponding other components can be suctioned in gas and/or vapor form out of the vacuum tank by means of the vacuum pump. The known atomization means has an atomizer nozzle for the fluid mixture, and the liquid components can be drained by mean of a hydraulic pump which can be driven by a hydraulic motor, which form a structural unit located within the vacuum tank. The indicated hydraulic motor can be driven by the fluid mixture which can be set into motion by another drive as soon as a definable fill level in the vacuum tank requires discharge of the component which is liquid at the time by means of the hydraulic pump. Based on the atomization means it is possible to achieve almost optimum separation of the components with a small structural size of the device, separation also being economically favorable with respect to energy input. But it has been found that especially in applications at low and very low temperatures the atomization means is fault-susceptible and is not especially well suited.

[0004] Based on the above described prior art, the object of the invention is to improve a device for separating fluid mixtures, in particular for separating oil and water, with a low structural size, while retaining the advantages, which allows optimum separation of the components and can be operated economically favorably, in such a way that it can also be used at low and very low temperatures. The pertinent object is achieved by a device with the features of claim 1.

[0005] In that, as specified in the characterizing portion of claim 1, one of the sub-chambers of the vacuum tank holds a heating means which is used to heat the fluid mixture which, routed to another sub-chamber as it flows through the packed bed, undergoes separation into its components, it is possible to deliver cold and consequently viscous fluid mixtures by means of the heating means to separation within the indicated vacuum tank. Thus the separation device as claimed in the invention also becomes of interest for use in construction machinery and military vehicles, where outside of maintenance installations with the corresponding building equipment, therefore also in the field, servicing of the hydraulic fluid can be undertaken by the water being separated from the oil. Another application consists also in separation of water from gasoline or water from kerosene, for example in aircraft.

[0006] The heating means, preferably in the form of an electrically operated heating means, can be regulated in terms of its heating output and can also be tailored so that in a wide range of temperatures of the fluid mixture it can be handled appropriately in terms of separation within the separation device. Integration of the heating means into one sub-chamber of the vacuum tank results in that only a small portion of the heat is released to the vicinity; this leads to improved efficiency and also improves the rate of water removal.

[0007] In one preferred embodiment of the device as claimed in the invention, one sub-chamber with the integrated heating means extends along the entire vacuum tank, the other sub-chamber with the packed bed encompassing the first sub-chamber, and another third sub-chamber coaxially to the second sub-chamber and in the lengthwise direction of the vacuum tank likewise following the latter encompassing the first sub-chamber. Division into different sub-chambers within the vacuum tank ensures that the heating means can occupy a large amount of space within the vacuum tank; this is advantageous in that the fluid mixture can then be routed over a very long section along the heating means. A correspondingly long residence time in the second sub-chamber is ensured by way of the other sub-chamber with the packed bed then, so that a longer time interval is available for the separation or gas removal process. Rapid drainage of the separated liquid portions from the vacuum tank to the outside is then possible by way of the other third sub-chamber with the packed bed.

[0008] In another preferred embodiment of the device as claimed in the invention, in a fourth sub-chamber which extends parallel to the first sub-chamber within the entire vacuum tank there is a level monitoring means which provides information about the fill level of the vacuum tank relative to the respective liquid component. Preferably it is provided here that the level monitoring means triggers a first delivery means such that when a given fill level boundary is not reached within the vacuum tank, the liquid component leaving the tank is passed onto the first sub-chamber with the heating means. Regardless of the fill level of the separation device and especially of the vacuum tank it is consequently possible to conduct a continuing separation process which is especially independent of how much fluid mixture to be separated is being supplied from the outside to the separation device. In addition to this more or less continuous operation which proceeds moreover favorably in terms of energy input, the fluid mixture which has already been separated can again be supplied to the actual separation device again in order to improve the separation results in further separation process. In this respect it is then ensured that fluid from which the air and water have been almost completely removed leaves the separation device for its further application.

[0009] In another preferred embodiment of the device as claimed in the invention, another delivery means by way of a filter unit withdraws the fluid mixture from a withdrawal point, the first delivery means by way of a switching means delivering the liquid component to the withdrawal point, alternatively to delivery to the heating means. If the level monitoring means shows that the fill level within the vacuum tank and especially in its fourth sub-chamber is too high, a switching valve is actuated accordingly and by way of the first delivery means, especially in the form of a motor-hydraulic pump unit, the liquid component is passed directly onto the withdrawal point from which in turn the separation device removes the fluid mixture by the second delivery means. The respective withdrawal point which is shared can be formed for example by the fluid tank of a construction machine or a military vehicle, such as a tank or armored personnel carrier.

[0010] In another preferred embodiment of the device as claimed in the invention, the vacuum pump with its suction force adjoins the top of the vacuum tank, in the opposite direction of the fluid mixture flow taking place from top to bottom through the second sub-chamber with the packed bed. The arrangement of the vacuum pump which is the top arrangement in this respect and also the countercurrent principle within the vacuum tank ensure a high separation rate and moreover streamlining within the vacuum tank for the medium which is flowing at the time is achieved.

[0011] In another preferred embodiment of the device as claimed in the invention, the vacuum tank can be connected to an air supply, and preferably by way of a filter unit and an adjustable choke. In this way then purified air in definable amounts can be supplied to the vacuum tank in order to be able to set and specify the respective negative pressure in the vacuum tank in this way. Preferably it is furthermore provided that the fluid-carrying connection to the heating means and the parts of the fluid lines in the delivery means which are each supplied by a hydraulic pump discharge into a common connecting piece. In this way the free path and use of pipework can be reduced.

[0012] If the device is assembled with all its components to be mobile in a transport unit, the separation device can be used on site so that in a military application a military vehicle can also be repaired and maintained in the open field.

[0013] The separation device as claimed in the invention is detailed below using one embodiment as shown in the drawings. The figures are schematic and not to scale.

[0014] FIG. 1 shows the basic connection diagram of the separation device;

[0015] FIG. 2 shows the separation device which implements the connection as shown in FIG. 1 as a mobile transport unit.

[0016] The device for separating fluid mixtures, especially water from oil, has a vacuum tank 10 into which the fluid mixture, here in the form of an oil/water mixture, can be delivered. The liquid component of the fluid mixture, here in the form of oil or another hydraulic medium, after completed separation can be transported out of the vacuum tank 10 by a delivery means which is designated as a whole as 12. The delivery means 12 which is the first one in this case has a hydraulic pump 16 which can be driven by an electric motor 14. For the respective removal the first delivery means 12 is connected by way of a pipeline 18 to carry fluid on the bottom of the vacuum tank 10. Furthermore, the separation device has a vacuum pump 20 which is conventional for applications in this respect and which is connected by way of a connecting line 22 which is shown only partially in FIG. 2 in the upper part of the vacuum tank 10 to the latter, carrying fluid. The output 24 of the vacuum pump 20 can be connected to a receiving tank which is not detailed or to another liquid drain line (neither is shown). If the vacuum pump 20 must release air to the vicinity, there can be a corresponding release device which is not detailed. In any event, water vapor in the form of a gas and/or in the form of steam can be safety released from the vacuum tank 10 by means of the vacuum pump 20. As can be seen from FIG. 2, the conveyor means 12 of the separation device is located as a unit underneath the vacuum tank 10. As a modular component the vacuum pump 20 is in turn a component of the separation device, in the direction of looking at FIG. 2 seen from the right and above this delivery means 12 and likewise outside of the vacuum tank 12.

[0017] As is to be seen from FIG. 2, the vacuum tank 10 is divided into several sub-chambers. The first sub-chamber 26 extends off-center along the entire vacuum tank 10 and is made in the manner of a hollow cylinder. Within this first sub-chamber 26 as part of a heating means 28 there is an electrically heatable heating rod 30. The heating rod 30 which likewise has a cylindrical outside profile, fits into the first sub-chamber 26 while maintaining a radial distance, the distance established in this way being used for fluid transport of the fluid mixture which is still to be separated. The transport direction of the fluid mixture within the first sub-chamber 26 is indicated with the corresponding arrows. The heating rod 30 itself viewed in the direction of looking at FIG. 2 with its top end is held by the sealing plate 32 of the vacuum tank 10, the heating rod 30 as part of a heating means being provided with an electrical supply 34.

[0018] Fundamentally the heating rod 30 of the heating means 28 works in the manner of electrical resistance heating, as is known from immersion heaters or the like. The cylindrical first sub-chamber 26 on the other hand viewed in the direction of looking at FIG. 2 with its bottom end rests on a lower end plate 36 which seals the vacuum tank 10 to the bottom. Conversely, on its other end the first sub-chamber 26 with its outside wall has a distance to the upper sealing plate 32 so that the fluid mixture can leave the first sub-chamber 26 by way of the separating gap 38 which has been formed in this way, in order to be released to the second additional sub-chamber 40. The respective second sub-chamber 40 is located coaxially to the first sub-chamber 26 and encompasses it with its cylindrical outside wall. In this way, within the second sub-chamber 40 a receiving space 42 is formed which is used to hold a packed bed which is not detailed. The packed bed in this respect can consist for example of special steel material with a plurality of individual filaments or the like in order to increase the surface for the fluid mixture which is to be separated in this way in the manner of a shower bed. Furthermore, the residence time of the fluid mixture which is to be separated in the second sub-chamber 40 is increased by the packed bed so that with respect to this longer residence time, more and more time is available for the actual separation process.

[0019] By integrating the heating means 28 into the vacuum tank 10 and especially into the first sub-chamber 26 only a small portion of the amount of heat is released to the vicinity, so that improved efficiency and an improved rate of water removal are achieved. By heating the fluid mixture, better separation of the water/oil mixture by way of the vacuum pump 20 is possible, which pump otherwise discharges with the free end of its connecting line 22 into the vacuum tank 10, and directly into the second sub-chamber 40 with the packed bed. If the fluid mixture which has been delivered to the first sub-chamber 26 is highly supercooled, there is also the possibility of heating the fluid mixture which is to be separated accordingly; this benefits the separation process. Furthermore, it is also possible to treat unusually viscous fluid, as occurs at low temperatures, by way of the separating device.

[0020] In the fluid direction downstream and moreover underneath the second sub-chamber 40 there is a third sub-chamber 44 which is separated by way of a type of separating or perforated sheet 46 from the second sub-chamber 40. In this way the packed bed which is not detailed can be supported on the top of the separating or perforated sheet 46 and removal of the liquid components of the fluid mixture from which water has been removed to the third sub-chamber 44 is ensured by way of the pertinent separating means 46. The third sub-chamber 44 in turn encompasses likewise in a coaxial arrangement the first sub-chamber 26 and otherwise terminates in terms of its outside diameter flush with the outside diameter of the second sub-chamber 40. The already addressed pipeline 18 which is connected to the first delivery means 12 accordingly fits into the third sub-chamber 44, carrying fluid with its other end. The second and third sub-chamber 40 and 44 extend jointly along the entire vacuum tank 10 and first end flush with the sealing plate 32 and then with the end plate 36. On the bottom end of the third sub-chamber 44 it however has an opening 48 which produces a fluid-carrying connection to the other fourth sub-chamber 50.

[0021] Depending on the overall fill level situation within the vacuum tank 10, in the fourth sub-chamber 50 a corresponding fluid level arises, a level monitoring means designated as a whole as 52 which monitors and adjusts the pertinent fill level. For this purpose the level monitoring means by way of an electrical terminal located on the top of the sealing plate 32 is connected to a control means which is designated 56 as a whole and which also has the corresponding control panel inputs and an emergency off function 58.

[0022] The indicated level monitoring means 52 within the fourth sub-chamber 50 has a lengthwise rod 60 along which a float-buoyancy body is movably located, depending on the respective fill level within the fourth sub-chamber 50, which allows a conclusion about the overall fill level situation within the vacuum tank 10 regarding fluid. The float-buoyancy body can move between a minimum position 62 and a maximum position 66. The respective fluid level moves between these positions 62 and 66 and furthermore there is an emergency off float 64 available for safety purposes. The limit switches (not shown) which are monitored by way of the control means 56 provide for the first delivery means 12 to be triggered upon reaching the lower limit switch and consequently at a low fill level within the vacuum tank 10 such that the liquid component leaving the vacuum tank 10 by way of the third sub-chamber 44 is passed directly onto the first sub-chamber 26 with the heating means 28. For this reason the control means 56 controls a 3/2-way switching valve 68 which in its actuated position clears the fluid-carrying path between the pipeline 18 and the hydraulic pump 16 to a connecting line 70 which discharges exclusively into the fluid-carrying area of the first sub-chamber 26 by way of the lower end plate 36.

[0023] When the float-buoyancy body reaches the top limit switch, the level monitoring means 52 by way of the control means 56 triggers the 3/2-way switching valve such that it retains its unactuated position shown in FIG. 1, in which the pipeline 18 is connected by way of the hydraulic pump 16 to a drain line 72, as shown, which discharges with its free end by way of an hand-actuated check valve 74 into a withdrawal point, for example in the form of a tank T. In the pertinent operating position it can be ensured that the vacuum tank 10 with its sub-chambers cannot be overfilled, but that reliable drainage in the direction of the tank T is possible. Consequently, it is possible by way of the level monitoring means 52 and the control means 56 to exactly adjust the fill and working state, with undersupply of the vacuum tank 10 the liquid fluid which has already been separated in the sense of an internal closed return flow being routed back to the first sub-chamber 26 with the heating means 28.

[0024] In order to be able to ensure the supply of the vacuum tank 10 with the fluid mixture which is to be separated at all, the separation device furthermore has a second delivery means 76 which in turn has a hydraulic pump 80 which can be driven by means of an electric motor 78. The indicated motors 14 and 78 can of course also consist of ordinary hydraulic motors. The hydraulic pump 80 by way of a withdrawal line 82 and a coarse filter 84 and by way of another hand-actuated shut-off means 86 removes fluid from the withdrawal point in the form of the tank T and passes the water-containing fluid mixture which is thus conveyed on to a filter unit 88 which by way of a spring-loaded nonreturn valve 90 ensures that fluid cannot flow back to the filter unit 88 unintentionally in the opposite direction out of the connecting line 70 and by way of the delivery line 92. Otherwise this would be possible for example if the hydraulic pump 80 were not to build up a sufficient fluid pressure. By way of the pertinent second transport or delivery means 76 the supply of the vacuum tank 10, especially the supply of the first sub-chamber 26 with the heating means 28 from the withdrawal point (tank T), is ensured. The withdrawal site or tank T itself can in turn be supplied continuously, but also discontinuously with the fluid mixture which is to be separated from the machine side.

[0025] To prevent negative pressure from developing in the vacuum tank 10 such that the operation of the entire device could be at risk, provision is made such that the vacuum tank 10 be connected to an air feed 94 which has an air filter 96 and an adjustable choke 98. The air feed into the vacuum tank 10 can be dictated by way of the latter choke 98. Furthermore, by way of the air filter 96 it is ensured that contaminated air could not penetrate into the vacuum tank 10 and could adversely affect the separation process there. The fluid-carrying connection 70 to the heating means 28, 30 and parts of the fluid lines 92 of the delivery means 12, 76 which are each supplied by the hydraulic pump 16, 80 discharge into a common connecting piece 100 which allows supply of the vacuum tank 10 first by way of the external supply from the tank T and then by way of the inner circulation depending on the fill level within the vacuum tank 10. As follows furthermore from FIG. 2, all the aforementioned components of the device are combined to be mobile in a transport unit 102, in this case transport on a factory floor, road or the like being possible by means of a set 104 of wheels, for example, in the form of four individual wheels. Rail or air cushion operation would also be conceivable.

[0026] In addition to the indicated removal of water from the oil/water mixture, the device can also be used for comparable fluid mixtures, for example to remove aqueous condensates from aviation fuel (kerosene) in the tanks of aircraft.

[0027] In addition to the indicated automatic operation of the water removal system, it is moreover possible to monitor the pressure situation in the vacuum tank 10 by way of a connected pressure gauge 106 (compare FIG. 1); this also aids safety. Within the vacuum tank 10 preferably a working temperature from roughly 20° C. to roughly 60° C., depending on the application, is used and an absolute pressure of 22,000 Pa (200 mbar) is set; this corresponds to a negative pressure of 80,000 Pa (0.8 bar). Overall the device is set such that a working point in the vicinity of the vapor pressure curve of water develops which is preferably slightly above the vapor pressure curve. A working point slightly above the vapor pressure curve can be easily technically achieved and in terms of energy is within acceptable limits. In the area of this working point or working range the water vapor then separates from the oil-water mist in the area of the fluidized bed and can be diverted by way of the intake area by means of the vacuum pump 20 out of the vacuum tank 10. The oil mist itself settles on the bottom of the fluidized bed and moreover in the area of the separating or perforated sheet 46 at latest as liquid and visibly fills the third sub-chamber 44 and moreover also the fourth sub-chamber 50 of the level monitoring means 52.

[0028] In the indicated separation process, in addition to removing water from oil, removal of gas from it is also achieved, the gases likewise collecting in the intake area of the vacuum pump 20 and in this way being removed at the same time from the vacuum tank 10. The feed line of the fluid mixture which is to be separated to the heating rod 30 of the heating means 28 in the vacuum tank 10 acts like a heat exchanger and preheats the inflowing fluid mixture. This likewise benefits the efficiency and water removal rate of the device as claimed in the invention, since only a limited amount of heat per area can be transferred to the fluid mixture without damage occurring. Integrating the heating in the housing parts of the vacuum tank 10 moreover results in a space-saving and weight-reducing construction.

[0029] For better understanding, the entire device is now explained in conclusion using its manner of operation. The hydraulic pump 80 intakes the fluid mixture (oil/water mixture) to be separated from the tank T from which water is to be removed and fills the vacuum tank 10 by way of a filter 88 and the chamber with the heating rod 30. Moreover filtration and heating of the fluid mixture take place if the heating means 28 has been started by the control means 56. Based on the temperature and the set negative pressure, then water is removed from the oil in the vacuum tank 10. At the same time oil is delivered by way of the hydraulic pump 16 from the vacuum tank 10 and is supplied depending on the level switch signal of the level monitoring means 52 to the vacuum tank 10 or the tank T from which water is to be removed. If malfunctions occur, especially due to the vacuum tank 10 no longer being filled, the level monitoring means 52 especially by way of a switch located right at the bottom in the vacuum tank 10 can ascertain the pertinent complete emptying situation for the tank 10 and then undertake emergency shutdown, for example, by the control means 56 turning off the indicated hydraulic pumps 16, 80. As already described, humid air is intaken from the vacuum tank 10 by way of the vacuum pump and at the same time the room air which has been filtered by way of a so-called gas ballast choke 98 can be allowed to flow back into the vacuum tank 10 by way of the interface 94 and the filter unit 96. As a result of the pressure drop in the vacuum tank 10 the room air is then released and the water vapor partial pressure drops so that water can be removed from the oil.

Claims

1. A device for separating fluid mixtures, in particular for separating water from oil, comprising a vacuum tank (10) with several sub-chambers (26, 44, 40), and at least one liquid component of the fluid mixture can be transported out of the vacuum tank (10) after separation by a delivery means (12) and the corresponding other components can be extracted from the vacuum tank (10) in gas and/or vapor form by means of a vacuum pump (20), characterized in that one of the sub-chambers (26) of the vacuum tank (10) holds a heating means (28, 30) which is used to heat the fluid mixture which, routed to another sub-chamber (40) as it flows through the packed bed, undergoes separation into its components.

2. The device as claimed in claim 1, wherein one sub-chamber (26) with the integrated heating means (28) extends essentially along the entire vacuum tank (10), wherein the other sub-chamber (40) with the packed bed encompasses the first sub-chamber (26) and wherein another third sub-chamber (44) coaxially to the second sub-chamber (40) and in the lengthwise direction of the vacuum tank (10) likewise following the latter encompasses the first sub-chamber (26).

3. The device as claimed in claim 2, wherein in a fourth sub-chamber (50) which extends parallel to the first sub-chamber (26) within the entire vacuum tank (10) there is a level monitoring means (52) which provides information about the fill level of the vacuum tank (10) relative to the component which is liquid and which is to be drained.

4. The device as claimed in claim 3, wherein the level monitoring means (52) triggers a first delivery means (12) such that when a given fill level boundary is not reached within the vacuum tank (10), the liquid component leaving the tank (10) is passed onto the first sub-chamber (26) with the heating means (28).

5. The device as claimed in claim 4, wherein another delivery means (76) by way of a filter unit (88) withdraws the fluid mixture from a withdrawal point (tank T) and wherein the first delivery means (12) by way of a switching means (68) delivers the liquid component to the withdrawal point (T), alternatively to delivery to the heating means (28).

6. The device as claimed in one of claims 1 to 5, wherein the vacuum pump (20) with its suction force adjoins the top (32) of the vacuum tank (10) and wherein, in the opposite direction of the fluid mixture, flow taking place from top to bottom through the second sub-chamber (40) with the packed bed.

7. The device as claimed in one of claims 1 to 6, wherein the vacuum tank (10) can be connected to the air supply (94), and preferably by way of an air filter unit (96) and an adjustable choke (98).

8. The device as claimed in one of claims 5 to 7, wherein the fluid-carrying connection (70) to the heating means (28) and the parts of the fluid line (18, 92) of the delivery means (12, 76) which are each supplied by a hydraulic pump (16, 80) discharge into a common connecting piece (100).

9. The device as claimed in one of claims 1 to 8, wherein the heating means (28) is electrically operated.

10. The device as claimed in one of claims 1 to 9, wherein all its components are combined to be mobile in a transport unit (102).