Filtration systems for oil filtration, particularly for marine units such as marine engines

Abstract

A filtration system for a marine engine comprises an oil circuit with a main pump, at least one backwashable main filter arranged in the supply line of the circuit, a filtrate line for filtered oil filtrate upstream of the engine, a treatment branch with a treatment filter for treatment of the backwash fluid, a plurality of switchable diverter valves in the treatment branch between the backwash outlet of the main filter and a fluid inlet of the treatment filter, and at least one pump. To simplify the filtration system while meeting the engine manufacturer's requirements for purity, separation degree, and differential pressure, an outlet of the treatment filter is connected to the filtrate line, and a switchable multi-way valve has at least first and second valve outlets arranged in the treatment branch, a first valve outlet is connected to the fluid inlet of the treatment filter, and a second valve outlet is connected to the supply line upstream of the main filter.

Description

[Technical Field]

[0001] The present invention relates to a filtration system for filtering oil, in particular for filtering oil of a marine unit such as a marine engine in an oil circuit having a main pump, the filtration system comprising at least one backflushable main filter arranged in a supply line of the oil circuit and having a filter housing with an oil inlet, a filtrate outlet, a backflush outlet and a backflush device, The system includes a filtrate line for filtered oil filtrate between the filtrate outlet and the marine unit, a treatment branch for backwash fluid connected to the backwash outlet and having at least one treatment filter having a filter housing, a fluid inlet, and a fluid outlet, a plurality of switchable diverter valves, and at least one pump in the treatment branch between the backwash outlet of the main filter and the fluid inlet of the treatment filter. [Background technology]

[0002] Filtration systems in a ship's oil circuit serve to protect the marine units connected to them. Oil filtration systems are used in the lubrication oil circuits of ships, especially marine engines used to propel the ship, such as large diesel engines. In this case, large volumes of oil must be filtered, while high levels of contamination of the lubricating or hydraulic oil must be reliably removed. At the same time, since ships can travel for weeks with their engines running continuously, the filtration system must operate accurately over long periods of time, even at extreme or extremely fluctuating temperatures and pressures. Therefore, marine engine manufacturers define the purity that must be maintained in such filtration systems, because otherwise it would be impossible to achieve certification and approval of the filtration systems for their engines.

[0003] Numerous solutions and proposals for corresponding filtration systems already exist in the prior art. See, for example, WO 2018 / 0028221 A1 and JP 2007 / 125479 A or JP 6469198 B1 filed by the applicant. In all of the above-mentioned filtration systems, a switchable multi-way valve is arranged upstream of the main filter, and the treatment filter simultaneously forms, if appropriate, a bypass filter solely responsible for treating the filtrate supplied to the marine unit. However, in normal operation, when the main flow filter is receiving flow, the backwash fluid treated by the treatment filter is supplied to the oil sump.

[0004] The premise of the present invention is based on WO2017 / 085643A1. In this type of filtration system, a switchable multi-way valve is arranged upstream of the main filter, the main filter is supplied with oil directly from the oil sump, and a treatment filter treats the backflush fluid, or the treatment filter is connected upstream of the main filter during the engine start-up phase to ensure a greater filtering of impurities, particularly those arising from engine production. A pump arranged in the treatment circuit is then used as a means to guide the backflush fluid generated in the main filter upstream of the treatment filter in this switching position of the upstream multi-way valve. Meanwhile, during normal operation, the fluid oil treated by the treatment filter is supplied to the engine sump or oil sump.

[0005] The demands on filtration systems for marine units are increasing. Some marine engine manufacturers are now requiring that filtration systems must be designed in such a way that relatively large pressure fluctuations can be avoided, even in continuous operation. While this is in principle possible with existing filtration systems if a disproportionately large filter surface area were made available, this is not possible on ships for reasons of space alone, and is not economically viable overall. Summary of the Invention [Problem to be solved by the invention]

[0006] The object of the present invention is to further simplify filtration systems for marine units while meeting engine manufacturer requirements in terms of purity and separation and differential pressure to be maintained, and also allowing maintenance options for the filtration system during operation. [Means for solving the problem]

[0007] To achieve this goal, the present invention proposes that the treatment filter's fluid outlet be connected to the filtrate line, and that a switchable multi-way valve having a valve inlet and at least one first and second valve outlets be arranged in the treatment branch between the pump and the treatment filter's inlet, with the first valve outlet of the multi-way valve connected to the treatment filter's fluid inlet and the second valve outlet connected to the supply line upstream of the main filter. In this solution, the automatic filter performs substantially continuous filtering of the oil flowing to the marine unit, thus eliminating the need for a switch, as required in filtration systems of this type, to connect the treatment filter upstream of the main filter. This takes advantage of the fact that backwashable main filters (autofilters) can already meet, and in fact even exceed, the requirements for purity and degree of separation required by marine engine manufacturers. Since the oil flowing into the marine unit is constantly filtered by the main filter (autofilter) during operation, including the startup phase, the main filter's filtering surface area is always available during operation. At the same time, the present invention allows the fluid stream treated by the treatment filter to be available to the marine unit as a usable amount of oil. Therefore, the entire amount of oil supplied to the main filter is available to the marine unit during normal operation, not only when backflushing is not currently taking place, but also during the backflushing phase of the main filter. Because the flushed oil treated by the treatment filter is available to the marine unit and the filter area of ​​the main filter is always available, the filter area that must be provided in the treatment filter can be reduced compared to systems in which only the treatment filter performs filtration during startup. The amount of filtered oil available to the marine unit is also not reduced. Unlike many prior art solutions, the switchable multiway valve in the treatment branch allows the treatment filter to be maintained, particularly cleaned or replaced, during operation. In such cases, the untreated flushed oil can be temporarily returned upstream of the main filter or main filter unit, or can be supplied to the main filter unit in the presence of an oil sump.

[0008] According to a particularly preferred embodiment, the backwashable main filter includes a first main filter unit with a backwash device and a second main filter unit with a backwash device, each of which is assigned a separate backwash outlet. Each backwash outlet is connected to or opens a dedicated flush line with a switchable flush valve to a treatment branch upstream of the pump. If one main filter unit fails, the other main filter unit can still ensure that a sufficient amount of filtered oil is supplied to the marine unit, even if a differential pressure could increase during operation if one main filter unit fails. In the case of two main filter units with separate flush valves, it is particularly advantageous if a control unit is used to ensure that at least one of the two switchable flush valves is closed during any operation. This can increase the effectiveness of backflushing (backwashing) while simultaneously reducing the amount of flushing oil required for backflushing.

[0009] The configuration of the filtration system is preferably such that the main filter or each main filter unit is designed as an intermittent flusher, with backflushing preferably only taking place when the associated flushing valve is open. The configuration of the main filter or main filter unit as an intermittent flusher simultaneously opens up additional operating possibilities and operating variants in the treatment branch.

[0010] It is particularly advantageous, in a manner known per se, if the main filter or main filter unit is assigned a bypass branch including a protective filter and an overflow unit with a pressure relief valve, the bypass branch opening into a filtrate line downstream of the protective filter and the overflow unit. Even in the event of failure of both main filter units, a sufficient fluid flow of filtered oil to the marine unit can be provided, with filtration being performed exclusively by the protective filter in this exceptional case. According to one variant, for this purpose, a differential pressure monitoring device can be assigned to the main filter or main filter unit, and the pressure relief valve of the overflow unit can be activated or is activated depending on the differential pressure determined by the differential pressure monitoring device and can open or is opened, particularly by a switching action, when a predetermined differential pressure is exceeded. According to an alternative variant, the pressure relief valve of the overflow unit can have an adjustment device for the trigger pressure, and the pressure relief valve opens automatically when the trigger pressure is exceeded. For this purpose, the adjustment device can, in particular, have a compression spring whose prestress can be adjusted by the adjustment device. In both variants, it is particularly advantageous if a detection unit is assigned to the overflow unit, by means of which opening of the pressure relief valve can be detected and preferably each opening action can be transmitted to a control device. In the evaluation, each opening action can then be tracked at any time, an analysis can be carried out and, if appropriate, it is also possible to determine how long the overflow unit has been active or open. However, in many cases, the knowledge that the overflow unit has been open is already sufficient to carry out maintenance.

[0011] The filtration system allows operation without an oil sump. However, an oil sump is usually interposed in the oil circuit between the marine unit and the supply line. If an oil sump is present, according to one embodiment, the second valve outlet of the multi-way valve in the treatment branch can open directly into the supply line upstream of the main pump. According to an alternative configuration of the filtration system with an oil sump in the oil circuit, the second valve outlet of the multi-way valve in the treatment branch can open directly into the oil sump, to which the supply line to which the main pump is provided is also connected.

[0012] In order to meet and even exceed the requirements of engine manufacturers regarding purity, it is particularly advantageous if the main filter or main filter unit has one or more filter elements with a beta value of at least β6 ≥ 8, i.e., the ratio between the number of particles of a certain same size upstream and downstream of the filter, respectively, at least β6 ≥ 10, or β6 ≥ 20, and / or if the treatment filter has filter elements with a beta value of at least β6 ≥ 8, or β6 ≥ 10, or β6 ≥ 20, or β6 ≥ 75. If an overflow unit with a protective filter is present, it is also advantageous if the protective filter is ≤ 25 μ It is particularly advantageous to have a filter medium with a filter fineness of 1000 m (micrometer).

[0013] If the main filter unit is equipped with a filter media with a β6≧8 or β6≧10, it exceeds the requirements of many engine manufacturers for normal operation, allowing the main filter to meet separation performance requirements under all operating conditions. A backwashable main filter unit facilitates a long service life without the need for filter replacement. Because impurities are removed from the entire system within the treatment filter, there is a high degree of flexibility and adaptability regarding the size of the treatment filter, thereby further reducing the overall area required on the vessel for the filtration system. A pump connected upstream of the treatment filter further increases the absorption capacity of the treatment filter. Since the flushing pump connected upstream of the treatment filter does not necessarily need to be able to handle the main flow rate at any given time during operation, it is sufficient to design the flushing pump for a relatively small flow rate.

[0014] In a particularly advantageous configuration, the or each main filter unit preferably has as backflushing device only one filter cartridge with a backflushing element arranged inside the filter cartridge so that it can rotate about the central axis of the filter cartridge, the backflushing element being preferably coupled to a rotary drive, in particular an electric motor as the rotary drive.It is particularly advantageous if the rotary drive, or a control device for the rotary drive, is coupled to the flushing valve or to the flushing valve, whereby the duration of the opening of the flushing valve per opening movement coincides with the duration of a 360° rotation of the backflushing element in the filter cartridge.

[0015] In particular, when the main filter or main filter unit is designed as an intermittent flusher, one advantageous configuration is for the treatment filter to have or form a settling chamber, preferably a replaceable filter basket with a closed bottom, an inlet opening located above the filter basket, and a collection space for filtrate surrounding the filter basket. The provision of settling significantly increases the dirt absorption capacity and, therefore, the service life of the treatment filter. At the same time, settling allows the fineness of the treatment filter to be further increased, possibly up to β6≧100.

[0016] Further advantages and configurations of the filtration system according to the invention will become apparent from the following description of advantageous exemplary embodiments shown in the drawings. [Brief explanation of the drawings]

[0017] [Figure 1] FIG. 1 shows a schematic diagram of a filtration system according to the invention for an oil circuit for a marine unit in normal operation. [Figure 2] FIG. 2 shows a schematic representation of the filtration system of FIG. 1 during the backflushing process of the first main filter unit. [Figure 3] FIG. 3 shows schematically the filtration system from FIG. 1 during the backflushing process of the second main filter unit. [Figure 4] FIG. 4 shows schematically the filtration system from FIG. 1 during the backflushing process of the first main filter unit and with the treatment branch blocked. [Figure 5] FIG. 5 shows a highly simplified longitudinal cross section of a preferred exemplary embodiment of the main filter. [Figure 6] FIG. 6 shows a highly simplified longitudinal cross section diagrammatically of a preferred exemplary embodiment of a treatment filter having a settling chamber. [Figure 7]FIG. 7 shows a schematic diagram of a filtration system according to the invention for an oil circuit for a marine unit having an oil sump during a backflushing process of the first main filter unit according to a variant of the first embodiment. [Figure 8] FIG. 8 shows a schematic diagram of a filtration system according to the invention for an oil circuit for a marine unit having an oil sump during a backflushing process of the first main filter unit according to a variant of the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0018] In Figures 1-4, reference numeral 10 designates the overall filtering system according to the present invention for the oil circuit of a marine unit 1. The oil circuit shown includes a main pump 22 in a supply line 3 originating from the marine unit 1, which supplies oil to a main filter 4 downstream of the marine unit 1. In the illustrated exemplary embodiment, the main filter 4, shown as a unit by dashed lines, is embodied in two main filter units 4A, 4B, which may have identical construction. Each of the two main filter units 4A, 4B has an oil inlet 5, a suitable filter medium 6, a filtrate outlet 7 and a backwash outlet 8A in the first main filter unit 4A, and a backwash outlet 8B in the second main filter unit 4B. The dashed lines also symbolically indicate the standard housing 13 of the main filter 4. In the illustrated exemplary embodiment, the filtrate outlets 7 of the two main filter units 4A, 4B are connected via an intermediate line to a filtrate line 9, through which the oil filtrate filtered by the main filter 4 or the main filter units 4A, 4B in the illustrated exemplary embodiment is supplied directly to the marine unit 1. The filter media 6 in the two main filter units 4A, 4B can be backwashed by a suitable backwash device, as will be described later, and for the backwash fluid (washing oil) emerging at the backwash outlet 8A or backwash outlet 8B of the main filter 4, a treatment branch 30 is provided, in which a separate treatment filter 31 is provided. The treatment filter 31 in the treatment branch 30 similarly comprises a filter housing 32 and a suitable filter element or filter media 36 between a fluid inlet 35 and a fluid outlet 37 of the treatment filter 31.

[0019] A multi-way valve 40 is connected upstream of the treatment filter 31 in the treatment branch 30. This multi-way valve 40 has a valve inlet 41, a first valve outlet 42, and a second valve outlet 42, preferably a 3 / 2-way valve. The fluid outlet 37 of the treatment filter 31 is connected to the filtrate line 9 via an intermediate line 38, which may include any desired shutoff member 39. The first valve outlet 42 of the switchable multi-way valve 40 in the treatment branch 30 is connected to the fluid inlet 35 of the treatment filter 31. The valve inlet 41 of the switchable multi-way valve 40 is supplied with backwash fluid or cleaning oil via a pump 25 if the backflow device of one of the two main filter units 4A, 4B is currently in operation. Since both main filter units 4A, 4B are embodied as intermittent flushers that do not continuously backwash the filter media 6 but only backwash for a certain period of time, backwash fluid is correspondingly not continuously present in the treatment branch 30. Backflushing actually occurs only when the flushing valve 11A, located between the backflushing outlet 8A and the pump 25, or when the flushing valve 11B, located between the backflushing outlet 8B of the main filter unit 4B and the pump 25, is open. The supply lines between the flushing oil outlets 8A, 8B and the pump 25 are provided via corresponding flushing lines 12A, 12B, respectively, and the respective flushing valves 11A, 11B are arranged accordingly. The flushing valves 11A, 11B are then connected via two electronic control lines 46A, 46B or via a wireless link to a central control unit 45, in this case. During operation, neither of the flushing valves 11A, 11B is open at any particular time, ensuring that backflushing does not occur or that at least one of the two flushing valves 11A, 11B is open. Therefore, the control unit 45 also monitors that at least one of the two flushing valves 11A, 11B is closed. The second valve outlet 43 of the switchable multi-way valve 40 in the treatment branch 30 is connected to the supply line 3 via an intermediate line 48, but is connected upstream of the pump 22 and downstream of a suitable shut-off member 24 or backflow shut-off member.

[0020] The filtration system 10 constructed as described above allows for numerous advantageous operating modes. FIG. 1 shows only an overall view with all system components. FIG. 2 illustrates the filtration system 10 in an operational state in which the filter media 6 of the main filter unit 4A is partially backflowed, while the entire filter surface area of ​​the filter media 6 of the main filter unit 4B is fully available to filter the volume of oil supplied to the marine unit 1 via the filtrate line 9. In the diagram shown in FIG. 2, closed lines through which no oil flows are indicated by dashed and dotted lines, while lines through which oil flows at least partially are indicated by solid lines. Because the flush valve 11A is open, the flush valve 11B is accordingly closed, and fluid does not flow through the flush line 12B as opposed to through the flush line 12A. The backwash fluid (flush oil) passes via the pump 25 to the multi-way valve 40 and through the valve outlet 42 of the multi-way valve to the fluid inlet 35 of the treatment filter 31 at a correspondingly increased pressure. The wash oil is appropriately treated in the filter material 36 of the treatment filter 31 and is supplied to the filtrate line 9 when the shut-off member 39 is open. Thus, at a certain point in time, for this operating mode, the entire fluid flow delivered by the main pump 22 is available to the marine unit 1, but one of the two main filter units, namely here main filter unit 4A, is partially in counter-flow mode.

[0021] 3 shows the backwashing of the main filter unit 4B by means of a comparable diagram. Accordingly, the flushing valve 11B opens and the flushing valve 11A closes. The backwash fluid generated in the main filter unit 4B is supplied via the pump 25 and the switchable multi-way valve 40 to the treatment filter 31 in the treatment branch 30 and is then available to the marine unit 1 via the filtrate line 9.

[0022] The diagram shown in Fig. 4 illustrates a special operating case, namely, when the filter capacity of the treatment filter 31 in the treatment branch 30 is exhausted. Thanks to the switchable multi-way valve 40 connected upstream of the fluid inlet 35 on the treatment filter 31 according to the present invention, any fluid supply to the treatment filter 31 can be interrupted in this case. Instead, the multi-way valve 40 is in a switching position in the diagram according to Fig. 4, similar to Fig. 1, in which the backwash fluid originating from the main filter unit 4A is returned untreated via the connecting line 49 to the supply line 3 upstream of the main pump 22. Again, the control unit 45 ensures that only the flushing valve 11A is open, while the flushing valve 11B is closed. In the corresponding switching state of the switching valve 40, the treatment filter 31 can be cleaned or replaced, particularly while the marine unit 1 and the entire filtration system 10 are in operation.

[0023] The main filter 4, which includes two main filter units 4A, 4B, further includes a bypass branch 51 with an overflow valve 52, as described with reference to FIG. 4. A protective filter 53 is connected downstream of the overflow valve 52 to ensure that unfiltered fluid is not supplied to the marine unit 1 under any circumstances. The bypass branch 51 with the overflow valve 52 and the protective filter 53 can be arranged in the main filter housing 13. The pressure relief valve 52 forms an overflow unit and preferably consists of a spring-loaded pressure relief valve (not shown), whose spring forms an adjusting device so that the trigger pressure for opening the pressure relief valve 52 can be adjusted by the spring. Thus, the pressure relief valve 52 of the overflow unit opens only when the differential pressure across the two main filter units 4A, 4B exceeds a preset value. The bypass branch 51 opens into the filtrate line 9 only downstream of the protective filter 53. In FIG. 4, a signal line 55 is further shown, by which each opening of the pressure relief valve 52 can be detected by the control unit 55 and noted within the control unit 45 for later analysis.

[0024] As already mentioned, the main filter 4 or each main filter unit 4A, 4B is in each case an intermittent flusher with a backwashing device, and the treatment filter 31 is preferably a stand-alone filter with a settling chamber that cannot be backwashed. A preferred configuration of the main filter unit is shown in Figure 5, and a preferred configuration of the treatment filter 31 is shown in Figure 6. Please refer first to Figure 5.

[0025] FIG. 5 shows, by way of example, one of the two main filter units 4A or 4B. The main filter unit 4 has a multi-component filter housing 62, inside which a single cylindrical filter cartridge 66 is located, which together with its peripheral wall forms the filter media 6. The oil to be filtered flows through the bottom region of the filter housing 62 into the interior of the filter cartridge 66. For this reason, for clarity, the reference number 5 for the filter inlet is assigned to the corresponding connecting flange on the filter housing 62. All oil that passes through the filter wall or filter media 6 as filtrate and enters the annular space 67 in the housing 62 surrounding the filter cartridge can be removed via the filtrate outlet 7 and then fed to a filtrate line in the oil circuit, thereby supplying the marine unit. The filter cartridge 66 is open at least at its lower end to allow oil to enter the interior of the filter cartridge 66. A backwashing element 68 is arranged inside the filter cartridge 66. The backwashing element 68 extends over the entire height of the filter cartridge 66 and is connected to a rotary drive 70, which is electrically operated and flange-mounted on the cover 69 of the housing 62 of the main filter units 4A and 4B. The rotary drive 70 can be operated so that the flushing element 68 continuously rotates inside the filter cartridge 66. Because the flushing element 68 extends with a slotted opening (not shown) adjacent to the inner periphery of the filter cartridge 66's peripheral wall, which forms the filter media 6, this movement, along with the resulting vortex currents, has the advantage of significantly preventing larger particles from adhering to the filter wall of the filter cartridge 66. When the differential pressure between the filter inlet 5 and the filtrate outlet 7 exceeds a preset value, which can be detected by the control device (45, Figures 1-4) or automatically triggered under differential pressure control, the flushing valves (11A and 11B, Figures 1-4) assigned to each main filter unit open to initiate backflow.Using the control device, the cleaning element's open duration can be set as a function of the rotation speed of the rotary drive 70 so that the open duration corresponds to approximately 360° of rotation of the backflushing element 68. Since the backflushing element 68 consists, for example, of a strip-shaped chamber with slotted openings, the remaining filter surface area of ​​the filter cartridge 66 not directly covered by the backflushing element 68 can simultaneously continue to filter the fluid entering the filter housing 2 via the filter inlet 5, while only a partial flow occurs as backflushing fluid, specifically during the backflushing process. The backflushing fluid can be supplied to the corresponding backflow outlets 8A, 8B at the bottom 65 of the housing 2 of the main filter units 4A, 4B via an internal channel (not shown) of a rotary shaft 71 coupled to the rotary drive 70 and the backflow element 68 for co-rotation.

[0026] Referring now to FIG. 6, an exemplary embodiment of a treatment filter 31 is shown schematically. It also includes a multi-component housing 32, and as in FIGS. 1-4, the fluid inlet is located adjacent to the cover portion 72 of the housing 32 and is designated by reference numeral 35, and the fluid outlet is located adjacent to a bottom trough 73 on the housing 32 and is designated by reference numeral 37. The fluid inlet 35 is located at an upper height of the filter housing 32 near the cover portion 72, and the fluid outlet 37 is located correspondingly at a lower height near the bottom trough 73. In the exemplary embodiment shown, the filter media 36 is comprised of a circumferential wall of a filter basket 75 that is closed at the bottom within the filter housing 32 and extends over a relatively high height. In the exemplary embodiment shown, the filter basket 75 has a bottom closure plate 77, while the filter basket 75 is open at its upper end. Cleaning oil, which flows only periodically through the fluid inlet 35 into the housing 32 of the treatment filter 31, flows slowly and evenly from above into the interior of the filter basket 75. As a result of this inflow guidance, the treatment filter 31 as a whole simultaneously functions as a settling chamber, allowing heavier residue that enters the treatment filter 31 or the filter basket 75 with the backwash fluid to settle to the bottom of the filter basket 75. The annular space 76 extends over the entire height of the filter basket 75 within the filter housing 32. The partial flow passing through the annular space 76 can then be discharged via the fluid outlet 37 and supplied to a filtrate line within the filtration system.

[0027] The filter media 6 in the main filter units 4A, 4B, on the one hand, and the filter media 36 in the treatment filter 31, on the other hand, are preferably selected to be filter elements with a filter medium of at least β6 ≥ 10, while filter elements 75 with the same filter fineness or even better filter fineness, e.g., β6 ≥ 75, are used in the treatment filter 31. In such a system, the quality of the circulating oil (fluid) is continuously improved. Replacement of the filter elements 75 of the treatment filter 31 in the treatment branch 30 is only performed after a certain operating time.

[0028] Figures 1-4 show a filtration system without an oil sump. The advantages resulting from the inventive configuration of a filtration system with a main filter or main filter unit and a treatment branch, as well as correspondingly arranged switching elements, can also be implemented with an oil sump. Figure 7 shows a first configuration of a filtration system 110, which is substantially identical to the exemplary embodiment according to Figures 1-4. For this reason, the same functional elements are designated by reference numerals increased by 100. As in the previous exemplary embodiment, oil flowing in the oil circuit in the supply line 103 is filtered by the main filter 104, which again may have two main filter units 104A, 104B, each equipped with a backwash device. As in the previous exemplary embodiment, the main filter 104 has a bypass branch 151 and is provided with a treatment branch 130 with a treatment filter 131, upstream of which is connected a pump 125 and a switchable multi-way valve 140 for treating the backwash fluid. The oil filtered by the main filter 104 is supplied to the marine unit 101 via the filtrate line 109. The first valve outlet of the multi-way valve 140 or the filter outlet of the treatment filter 131 connected downstream of the multi-way valve 140 also opens into the filtrate line 109. The deviation from the previous exemplary embodiment essentially consists in: Oil sump 190, into which fluid is introduced into the rear of the marine unit 101, from which oil is removed, and which is supplied by the main pump 122 to the main filter 104 via the supply line 103. As best shown in FIG. 7, the second valve outlet 143 is now the main pump 122's under The valve outlet 143 is connected to the supply line 103, but not to the oil sump 190. A backflow blocking member 199 prevents oil from flowing back into the oil sump 190 when the valve outlet 143 is open. Otherwise, the individual functional elements can be designed as in the previously described exemplary embodiment, for which reference is made to the previous description.

[0029] 8 also shows a modified exemplary embodiment of the filtration system 210, which, like the last-described embodiment, is again provided with an oil sump 290. Functionally identical elements are again provided with reference numbers increased by 100, including a supply line 203 with a main pump 222, a main filter 204 with two main filter units 204A, 204B, a control unit 245 for controlling flushing valves 211A, 211B, a treatment filter 231, and a treatment branch 230 with a switchable multi-way valve 240 arranged upstream of the treatment filter 231. The second valve outlet 243 of the multi-way valve leads to the oil sump 290 via a connecting line 286, as does a supply line 295 between the marine unit 201 and the oil sump 290. In the illustrated exemplary embodiment, the supply line 203 to the main filter 204, in which the main pump 222 is also arranged, then connects to the bottom of the oil sump 290. A backflow blocking element is not necessarily required here. Here too, the liquid filtered by the main filter 204 is supplied to the marine unit 201 via the filtrate line 209, which also opens to the first valve outlet of the multi-way valve 240 or the filter outlet of the treatment filter 231 connected downstream of the multi-way valve 240.

[0030] Numerous modifications intended to fall within the scope of protection of the appended claims will be apparent to those skilled in the art from the foregoing description. The structures shown in the figures are essential for the operation of the filtration system. Each main filter unit may have only a single filter element, a single main filter may be provided, or three or more main filter units may be provided. The exemplary embodiment of the main filter station shown in FIG. 5 is merely illustrative. The main filter unit may also have multiple filter elements in a single housing, as known per se to those skilled in the art. It is also possible to provide only a single main filter with a single filter element. Additional coarse filters or shutoff elements may be arranged throughout the circuit, even if efforts are made to manage with as few switching and shutoff elements as possible, including check valves.

[0031] The present invention is not limited to the above-described embodiments of the filtration system. Individual features of each embodiment can be combined with each other, even if not explicitly mentioned in the drawings. Furthermore, individual elements can be omitted without departing from the scope of protection and disclosure of the present application, as long as they do not have a direct functional relationship with other individual elements.

Claims

1. Filtration system for filtering oil, in particular for filtering oil of a marine unit such as a marine engine, in an oil circuit having a main pump (22; 122; 222), comprising: The filtration system comprises: at least one backwashable main filter (4; 104; 204) arranged in the supply line of the oil circuit and including a filter housing having an oil inlet, a filtrate outlet, a backwash outlet and a backwash device; a filtrate line (9; 109; 209) for filtered oil filtrate between the filtrate outlet (7) and the marine unit (1; 101; 201); a treatment branch for the backwash fluid, connected to said backwash outlet and having at least one treatment filter (31; 131; 231) with a filter housing (32), a fluid inlet (35) and a fluid outlet (37); A plurality of switchable switching valves are provided; and at least one pump in the treatment branch between the backwash outlet of the main filter and the fluid inlet of the treatment filter; the fluid outlet (37) of the treatment filter (31; 131; 231) is connected to the filtrate line (9; 109; 209); a switchable multi-way valve (40; 140; 240) having a valve inlet (41) and at least a first valve outlet (42) and a second valve outlet (43; 143; 243) is arranged in the treatment branch (30; 130; 230) between the pump (25; 125) and the fluid inlet (35) of the treatment filter, the first valve outlet (42) of the multi-way valve is connected to the fluid inlet (35) of the treatment filter (31) and the second valve outlet (43; 143; 243) is connected to the supply line (3; 103; 203) upstream of the main filter (4); A filtration system characterized by:

2. The backwashable main filter (4) comprises a first main filter unit (4A; 104A; 204A) having a backwashing device and a second main filter unit (4B; 104B; 204B) having a backwashing device; the backwash devices of the main filter units are assigned to separate backwash outlets (8A; 8B); 2. A filtration system according to claim 1, characterized in that each backwash outlet is connected to the treatment branch (30; 130; 230) upstream of the pump by a flushing line (12A; 12B) equipped with a switchable flushing valve (11A; 11B).

3. Filtration system according to claim 2, characterized in that a control unit (45; 245) is used as a means for ensuring that at any time during operation at least one of the two switchable flushing valves (11A; 11B) is closed.

4. 4. A filtration system according to any one of claims 1 to 3, characterized in that the or each main filter unit (4A; 4B) is designed as an intermittent flusher, and backwashing preferably only takes place when the associated flushing valve (11A; 11B) is open.

5. The main filter or main filter unit is assigned a bypass branch (51) containing a protective filter (53) and an overflow unit having a pressure relief valve (52), Filtration system according to any one of claims 1 to 4, characterized in that the bypass branch (51) opens into the filtrate line (9) downstream of the protective filter (53) and the overflow unit.

6. a differential pressure monitoring device is assigned to the main filter or the main filter unit; 6. The filtration system of claim 5, wherein the pressure relief valve of the overflow unit is operable or is operated in response to a differential pressure determined by the differential pressure monitoring device and is operable or is opened when a predetermined differential pressure is exceeded.

7. the pressure relief valve of the overflow unit has an adjustment device for trigger pressure; the pressure relief valve opens when the trigger pressure is exceeded; the adjusting device preferably comprises a compression spring, the prestress of which can be adjusted by means of the adjusting device; The filtration system of claim 5 .

8. The overflow unit is assigned a detection unit capable of detecting the opening of the pressure relief valve, and is preferably capable of transmitting each valve opening operation to a control device. The filtration system according to any one of claims 5 to 7.

9. an oil sump (190) interposed in the oil circuit between the marine unit and the supply line; 7. The filtration system according to claim 1, wherein the second valve outlet (143) of the multi-way valve in the treatment branch opens directly into the supply line (103) between the main pump (122) and the main filter (104).

10. 7. A filtration system according to any one of claims 1 to 6, characterized in that an oil sump (290) is interposed in the oil circuit between the marine unit and the supply line, and the second valve outlet (243) of the multi-way valve (240) in the treatment branch opens directly into the oil sump (290), to which the supply line (203) comprising the main pump is also connected.

11. The main filter or main filter unit has at least β ６ ≧8, or β ６ having one or more filter elements with ≥ 10 filter media (6); and / or The processing filter is at least β ６ ≧8, or β ６ ≧10, preferably β ６ 75% or more of a filter medium (36), The filtration system according to any one of claims 1 to 10.

12. 6. The filtration system of claim 5, wherein the protective filter (53) comprises a filter medium with a filter fineness of 25 μm (micrometers) or less.

13. The main filter or each main filter unit has, as a backwashing device, a filter cartridge (66) having a backwashing member (68) arranged inside the filter cartridge so as to be rotatable about the central axis of the filter cartridge; Filtration system according to any one of claims 1 to 12, characterized in that the backwashing member is preferably coupled to a rotary drive (70), in particular to an electric motor as rotary drive.

14. a rotary drive (70) or a control device for the rotary drive is coupled to the flushing valve or valves such that the duration of opening of said flushing valves per opening movement corresponds to the duration of a 360° rotation of the backwash element (68) in the filter cartridge (66), 14. The filtration system of claim 2 or claim 13.

15. Filtration system according to any one of claims 1 to 14, characterized in that the treatment filter (31) has or forms a settling chamber, preferably a replaceable filter basket (75) closed at the bottom, an inlet opening arranged above the filter basket, and a collection space (76) for the washing oil filtrate surrounding the filter basket.

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