Filter exchange device, electrochemical system and method

Abstract

The invention is based on a filter replacement device (10, 12, 14) for an electrochemical system (16), with at least one main fluid line (18) which comprises at least one main filter connection (20) for a fluidic connection to a main filter (22) of the electrochemical system (16), with at least one actuating unit (24) for blocking or opening the main filter connection (20) and with at least one replacement connection (26) for a fluidic connection of a secondary filter (28) of the electrochemical system (16) or an external maintenance device (30). It is proposed that the filter replacement device (10, 12, 14) comprises a further adjusting unit (32) for continuously adjusting a flow resistance of the main filter (22).

Description

State of the art

[0001] A filter replacement device for an electrochemical system has already been proposed, comprising at least one main fluid line, which comprises at least one main filter connection for fluidically connecting to a main filter of the electrochemical system, at least one actuating unit for blocking or opening the main filter connection, and at least one replacement connection for fluidically connecting a secondary filter of the electrochemical system or an external maintenance device. Disclosure of the invention

[0002] The invention is based on a filter replacement device for an electrochemical system, with at least one main fluid line, which comprises at least one main filter connection for a fluidic connection to a main filter of the electrochemical system, with at least one actuating unit for blocking or opening the main filter connection and with at least one replacement connection for a fluidic connection of a secondary filter of the electrochemical system or an external maintenance device.

[0003] It is proposed that the filter replacement device comprise a further actuating unit for continuously adjusting a flow resistance of the main filter. The filter replacement device is preferably designed for a fuel cell system and / or an electrolysis system as an electrochemical system. The filter replacement device is preferably provided for replacing a used main filter with a new main filter. The main filter is preferably provided for cleaning a process fluid of the electrochemical system of at least one additive, in particular for keeping a concentration of the additive in the process fluid below a maximum permissible limit. The process fluid is preferably a reactant or product of an electrochemical conversion carried out by the electrochemical system.The main filter is arranged, for example, in a reactant supply, in particular in a fuel supply or an air supply, of the electrochemical system, for example to filter sulfur, a sulfur compound, chromium, or the like from a fuel or to purify the air drawn in. The main filter is arranged, for example, at an air outlet of the electrochemical system.

[0004] The filter replacement device is preferably provided to maintain operation of the electrochemical system by means of the secondary filter while the main filter is being replaced. The at least one replacement connection is preferably arranged upstream of the main filter connection. The main filter connection preferably comprises at least one filter fluid inlet and at least one filter fluid outlet, which are provided for connecting the main filter. The replacement connection is preferably arranged upstream of the filter fluid inlet. The main fluid line preferably comprises at least one further replacement connection, which is arranged downstream of the main filter connection, in particular the filter fluid outlet. The replacement connections are preferably provided to fluidically connect the secondary filter to the main fluid line in parallel to the main filter.Preferably, the exchange connections are designed to be integrated with the actuating unit, for example in the form of a 3-way valve, in particular of type T. Alternatively, the exchange connection and / or the further exchange connection is designed as a T-piece, wherein the actuating unit comprises an actuating element at the outputs of the exchange connection and / or at the inputs of the further exchange connection.

[0005] The secondary filter can be an emergency filter of the electrochemical system, designed to be automatically activated upon detection of a coagent breakthrough through the main filter, or the secondary filter can be part of the external maintenance device, which is specifically connected to the replacement ports for the duration of the main filter replacement. The secondary filter generally does not have the same filter capacity and / or flow resistance as the main filter, so maintaining a constant flow rate cannot be guaranteed when changing from the used main filter to the secondary filter and / or from the secondary filter to the new main filter.The additional actuating unit is provided to at least partially compensate for differences in the capacity and / or flow resistance of the main filter and the secondary filter, and in particular to enable at least a minimum flow rate through the secondary filter when the main filter is replaced. The additional actuating unit is provided, in particular, to continuously, and in particular not abruptly, shift a ratio of the flow resistances of the main filter and the secondary filter when the main filter and the secondary filter are operated in parallel. The additional actuating unit preferably comprises at least one actuating element arranged in the main fluid line. The actuating element of the additional actuating unit is preferably arranged upstream of the main filter connection.Preferably, the actuating element of the further actuating unit is arranged downstream of the exchange connection, in particular downstream of an actuating element of the actuating unit on the exchange connection.

[0006] "Intended" should be understood in particular to mean specifically programmed, designed, and / or equipped. The fact that an object is intended for a specific function should be understood in particular to mean that the object fulfills and / or performs this specific function in at least one application and / or operating state.

[0007] The inventive design advantageously minimizes the risk of a flow blockage of the secondary filter during a change from the main filter to the secondary filter. In particular, the electrochemical system can advantageously continue to operate without disruption during a replacement of the main filter. In particular, fluctuations in the flow rate of the process fluid to be cleaned during the replacement can advantageously be minimized.

[0008] It is further proposed that the further actuating unit comprise at least one continuous valve, in particular in the form of a throttle valve, to adjust the flow resistance. Preferably, the aforementioned actuating element of the further actuating unit is designed as a continuous valve, in particular as an adjustable throttle valve. The design according to the invention advantageously allows the fluid exchange device to be manufactured simply and cost-effectively.

[0009] It is further proposed that the additional control unit comprise at least one pressure regulator to adjust the flow resistance. Preferably, the aforementioned control element of the additional control unit is designed as a pressure regulator. The inventive design allows a pressure drop across the main filter connection to be advantageously precisely adjusted and varied.

[0010] It is further proposed that the additional actuating unit, in particular the actuating element of the additional actuating unit, be arranged in the main fluid line upstream of the main filter connection. The inventive design allows the flow resistance of the main filter to be advantageously easily adapted to secondary filters with a smaller capacity and / or greater flow resistance.

[0011] Furthermore, an electrochemical system is proposed with at least one filter exchange device according to the invention and with at least one fuel processing unit, in particular a desulfurizer, connected to the filter exchange device. The electrochemical system preferably comprises at least one electrochemical unit with at least one electrochemical cell, preferably a plurality of electrochemical cells, in particular at least 100, preferably at least 200, electrochemical cells. The electrochemical cells are preferably designed as fuel cells, alternatively as electrolysis cells, in particular as solid oxide fuel cells, as solid oxide electrolysis cells, as polymer electrolyte fuel cells, as polymer electrolyte electrolysis cells, or the like.The electrochemical system preferably comprises at least one fuel supply connected to the at least one electrochemical unit, which comprises the fuel processing unit, which is provided for supplying the electrochemical cells with a fuel as a process fluid. The electrochemical system preferably comprises at least one air supply connected to the at least one electrochemical unit, which is provided for supplying the electrochemical cells with air. The fuel processing unit is preferably connected to the main filter connection of the filter exchange device. The fuel processing unit is or comprises the aforementioned main filter, which is preferably provided for filtering sulfur or sulfur compounds from the fuel.Due to the design according to the invention, a supply of fuel to the electrochemical cells can advantageously be maintained without interruption during a replacement of the main filter.

[0012] Furthermore, an electrochemical system, in particular the one already mentioned, with at least one, in particular further, filter exchange device and with at least one air treatment unit connected to the, in particular further, filter exchange device is proposed. The air treatment unit is preferably part of the air supply for supplying the electrochemical cells with treated, in particular purified, air. Alternatively, the air treatment unit is part of an air disposal system of the electrochemical system for discharging treated, in particular purified, air to the environment. The air treatment unit is preferably connected to the main filter connection of the, in particular further, filter exchange device. The air treatment unit preferably comprises the main filter or a further main filter intended to filter air.Due to the design according to the invention, a supply of air to the electrochemical cells can advantageously be maintained without interruption during a replacement of the main filter.

[0013] Furthermore, a method for operating an electrochemical system, in particular the one already mentioned, which has a filter replacement device according to the invention is proposed, wherein in at least one method step of the method for replacing the main filter, the flow resistance of the main fluid line is continuously adjusted. In particular, if the electrochemical system does not comprise an emergency filter connected to the replacement connection, an external maintenance device with the secondary filter is connected to the replacement connections in an assembly step of the method. Preferably, in an opening step of the method, the actuating unit is actuated in order to direct a fluid flow of the process fluid located in the main fluid line at least partially through the secondary filter.Preferably, in an adjustment phase of the method, the flow resistance of the main fluid line is increased continuously, in particular without sudden changes, by means of the further adjustment unit in order to increase a proportion of the fluid flow through the secondary filter and to reduce it in the main filter. Preferably, in a blocking step of the method, the main fluid line is closed by means of the adjustment unit so that the entire fluid flow of the process fluid flows through the secondary filter. Preferably, in a replacement step, the main filter is removed from the main fluid line and replaced with a new main filter. Preferably, in a further opening step of the method, the main fluid line is actuated by means of the adjustment unit in order to open the main fluid line.Preferably, in a further adjustment phase of the method, the flow resistance of the main fluid line is continuously, in particular smoothly, reduced by means of the further adjustment unit in order to reduce a proportion of the fluid flow through the secondary filter and increase it in the main filter. Preferably, in a further blocking step of the method, a fluid line through the secondary filter is closed by means of the adjustment unit. Preferably, in a disassembly step of the method, the external maintenance device with the secondary filter is removed from the replacement connections. The design according to the invention advantageously allows the risk of a flow-related blockage of the fluid flow during a change through the secondary filter to be kept low. In particular, different pressure drops between the main filter and the secondary filter can be compensated to an advantageously large extent.Furthermore, the electrochemical system can be advantageously supplied with the process fluid with low fluctuations even during a replacement of the main filter.

[0014] It is further proposed that in at least one method step of the method for replacing the main filter, the main filter connection and the replacement connection are opened simultaneously. In particular, in the setting phase and / or the further setting phase, the main filter and the secondary filter are operated in parallel and simultaneously flowed through by a proportion of the process fluid other than zero. Preferably, after the blocking step and before the further opening step, the process fluid only flows through the secondary filter and not the main filter. Preferably, before the opening step and after the further blocking step, the process fluid only flows through the main filter and not the secondary filter. The design according to the invention advantageously makes it possible to keep the extent of a sudden change in the fluid flow and / or pressure fluctuations when changing between the main filter and the secondary filter low.

[0015] It is further proposed that in at least one method step of the method for replacing the main filter, a fluid flow of the process fluid is continuously diverted by means of the further actuating unit from the main filter connection to the replacement connection or from the replacement connection to the main filter connection. Preferably, in the actuating phase, the fluid flow is continuously diverted from the main filter connection to the replacement connection, in particular until a proportion of the fluid flow through the main filter connection falls below a threshold value. The threshold value is preferably less than 15%, preferably less than 10%, particularly preferably less than 5%, of a maximum permissible fluid flow through the main filter. Particularly preferably, the fluid flow is continuously diverted until the further actuating unit reaches a maximum closed state.The additional actuating unit can optionally be provided to seal the main fluid line in a fluid-tight manner with respect to the process fluid. Preferably, during the actuating phase, the fluid flow is continuously diverted from the exchange connection to the main filter connection, in particular until a proportion of the fluid flow through the exchange connection falls below a threshold value. The threshold value is preferably less than 15%, preferably less than 10%, particularly preferably less than 5%, of a maximum permissible fluid flow through the secondary filter. Particularly preferably, the fluid flow is continuously diverted until the additional actuating unit reaches a desired opening state, in particular a maximum open state. The design according to the invention advantageously allows the extent of a sudden change in the fluid flow and / or pressure fluctuations when switching between the main filter and the secondary filter to be kept low.

[0016] Furthermore, it is proposed that in at least one method step of the method for replacing the main filter, a flow parameter of a fluid flow through the filter replacement device is controlled by means of the further actuating unit. The assembly step and the disassembly step are preferably carried out manually. The opening step and the further opening step are preferably carried out manually. The actuating phase, the blocking step, the further actuating phase and / or the further blocking step can be carried out manually or by a control or regulating unit of the filter replacement device, the electrochemical system or the external maintenance device. A "control and / or regulating unit" is to be understood in particular as a unit with at least one control electronics unit.The term “control electronics” should be understood in particular to mean a unit with a processor unit and a memory unit, as well as with an operating program stored in the memory unit. The actuating phase and / or the further actuating phase can, for example, be triggered by a sensor, such as a flow meter or a pressure meter, on the external maintenance device and / or the filter replacement device at one of the replacement connections. Alternatively, actuation of the actuating unit triggers the actuating phase and / or the further actuating phase. Alternatively, the actuating phase and / or the further actuating phase is triggered manually. An actual proportion of the fluid flow during the actuating phase and / or the further actuating phase can be actively monitored by the sensor of the filter replacement device and / or the external maintenance device in order to control the further actuating unit and the actuating unit depending on this.Alternatively, a temporal target profile of a degree of opening of the further actuating unit, which is determined in advance of the method, is stored in the memory unit of the control or regulating unit, depending on which target profile the control or regulating unit adjusts the further actuating unit. In an advantageously fault-free embodiment of the method, the control or regulating unit controls the further actuating unit and / or a fluid conveying unit of the electrochemical system, in particular additionally, depending on a total value of the fluid flow, the actual value of which is detected, for example, downstream of the further exchange connection by a sensor of the filter exchange device in order to keep the total value of the fluid flow constant in the actuating phase and / or the further actuating phase. By means of the embodiment according to the invention, a change between the main filter and the secondary filter can be carried out in an advantageously controlled and precise manner.

[0017] In particular, the risk of a positioning phase and / or a further positioning phase being carried out too quickly or unnecessarily slowly can be advantageously avoided.

[0018] The filter replacement device according to the invention, the electrochemical system according to the invention, and / or the method according to the invention are not intended to be limited to the application and embodiment described above. In particular, the filter replacement device according to the invention, the electrochemical system according to the invention, and / or the method according to the invention may, in order to fulfill a functionality described herein, have a number of individual elements, components, units, and method steps that differs from the number stated herein. Furthermore, in the value ranges specified in this disclosure, values within the stated limits are also to be considered disclosed and can be used arbitrarily. Drawings

[0019] Further advantages will become apparent from the following description of the drawings. The drawings illustrate an exemplary embodiment of the invention. The drawings, the description, and the claims contain numerous features in combination. Those skilled in the art will also expediently consider the features individually and combine them into useful further combinations.

[0020] They show: Fig. 1 a schematic representation of an electrochemical system according to the invention, Fig. 2 a schematic representation of a filter replacement device according to the invention, Fig. 3 a schematic sequence of states of the filter replacement device according to the invention during a method according to the invention and Fig. 4 a schematic time diagram of a flow rate of a process fluid of the electrochemical system according to the invention through the filter exchange device according to the invention in the context of the method according to the invention. Description of the embodiment

[0021] Fig. 1 shows an electrochemical system 16. The electrochemical system 16 is embodied, by way of example, as a fuel cell system. The electrochemical system 16 preferably comprises at least one electrochemical unit 42 for the electrochemical conversion of at least one fuel and air. The electrochemical unit 42 comprises a plurality of electrochemical cells, in particular solid oxide fuel cells or proton-conducting fuel cells. The electrochemical unit 42 has, for example, a nominal electrical output of at least 5 kW, preferably of at least 10 kW, in particular of at least 20 kW. Depending on the application, the electrochemical system 16 comprises a plurality of, in particular identical, electrochemical units 42, in particular at least two, preferably at least three, particularly preferably at least five, electrochemical units 42.The electrochemical units 42 are preferably designed for independent operation, in particular independent modulation. The electrochemical system 16 preferably comprises a central fuel supply 44, to which the at least one electrochemical unit 42 is connected, in particular all electrochemical units 42 are connected in parallel for fluidic purposes. The electrochemical system 16 preferably comprises a central or decentralized air supply 46, to which the at least one electrochemical unit 42 is connected, in particular all electrochemical units 42 are connected in parallel for fluidic purposes. The electrochemical system 16 preferably comprises an electrical unit 48 with at least one current converter, in particular inverter, for feeding an electrical current provided by the at least one electrochemical unit 42 into an external power grid or a consumer.The electrochemical units 42 can be electrically connected to the electrical unit 48 in series, parallel, or galvanically isolated. The electrochemical system 16 comprises, for example, a system controller 50 for controlling and coordinating the at least one electrochemical unit 42, in particular all electrochemical units 42, the fuel supply 44, the air supply 46, and / or the electrical unit 48. The system controller 50, the at least one electrochemical unit 42, in particular all electrochemical units 42, the fuel supply 44, the air supply 46, and / or the electrical unit 48 are preferably arranged in a common housing of the electrochemical system 16.

[0022] The central fuel supply 44 preferably comprises a fluid delivery unit 52 for subjecting the fuel to an inlet pressure. The central fuel supply 44 preferably comprises a fuel processing unit 34. The fuel processing unit 34 is preferably arranged downstream of the fluid delivery unit 52. The fuel processing unit 34 is preferably arranged upstream of a distributor of the fuel supply 44 for distributing the fuel to the individual electrochemical units 42. The fuel processing unit 34 preferably comprises at least one fuel filter for cleaning the fuel. The fuel filter is provided, for example, to filter sulfur and / or sulfur compounds from the fuel. The electrochemical system 16 preferably comprises at least one filter exchange device 10, which is connected to the fuel processing unit 34.

[0023] The air supply 46 comprises at least one housing air inlet for admitting air into the housing of the electrochemical system 16. The at least one electrochemical unit 42 preferably comprises a unit air inlet for admitting air into the electrochemical unit 42. The housing air inlet and the unit air inlet can be fluidically connected to one another through an interior of the housing or can be connected to one another via a closed line system. The unit air inlet preferably comprises an air treatment unit 36, in particular an air filter, for cleaning the air. The electrochemical system 16, in particular the at least one electrochemical unit 42, preferably comprises a filter exchange device 12 connected to the air treatment unit 36.The at least one electrochemical unit 42 preferably comprises at least one air outlet for discharging air from the electrochemical unit 42. The air outlet preferably comprises an air treatment unit 38, in particular an air filter, for cleaning the air. The electrochemical system 16, in particular the at least one electrochemical unit 42, preferably comprises a filter exchange device 14 connected to the air treatment unit 38.

[0024] Fig. 2 shows an example of the filter replacement device 10. The filter replacement devices 12 and 14 are preferably designed analogously. The filter replacement device 10 comprises at least one main fluid line 18. The main fluid line 18 comprises at least one main filter connection 20 for a fluidic connection to a main filter 22, which in the case of the filter replacement device 10 is the same as the fuel filter already mentioned. In the case of the filter replacement devices 12, 14, the main filter 22 is the same as the air filter of the air treatment unit 36 or the air treatment unit 38. The fuel treatment unit 34 and / or the air treatment unit 36, 38 can each comprise a main filter 22 or a plurality of main filters 22 connected fluidically in parallel and / or in series, which are provided in particular for individual replacement.The electrochemical system 16 can have a filter exchange device 10 for each main filter 22 and / or for a group of main filters, in particular for each treatment unit 34, 36, 38. The filter exchange device 10 comprises an actuating unit 24 for blocking or opening the main filter connection 20. The actuating unit 24 preferably comprises a first 3-way valve upstream of the main filter connection 20 and a further 3-way valve downstream of the main filter connection 20. The main fluid line 18 preferably extends from a main-filter-side fluid outlet 58 of the first 3-way valve to a main-filter-side fluid inlet 60 of the further 3-way valve. The filter replacement device 10 comprises at least one replacement connection 26 for fluidically connecting a secondary filter 28 of an external maintenance device 30. The replacement connection 26 is preferably formed by a further fluid outlet of the first 3-way valve.The filter replacement device 10 comprises at least one further replacement connection 56, which is preferably formed by a further fluid inlet of the further 3-way valve.

[0025] The external maintenance device 30 preferably comprises a bypass line 62, which is provided to connect the exchange port 26 to the further exchange port 56, bypassing the main filter port 20. The 3-way valves are preferably designed to direct a fluid flow 40, here of fuel or alternatively of air, in one position only through the main filter port 20, in one position only through the exchange port 26, and in one position fluidically parallel through the main filter port 20 and the exchange port 26.

[0026] The filter replacement device 10 comprises a further actuating unit 32 for continuously adjusting the flow resistance of the main filter 22. The further actuating unit 32 can be designed as a continuous valve, in particular in the form of a throttle valve, or a pressure regulator. The further actuating unit 32 is arranged in the main fluid line 18 upstream of the main filter connection 20 and in particular downstream of the main filter-side fluid outlet 58.

[0027] Fig. 3 shows a method 54 for operating an electrochemical system 16, wherein the main filter 22 is replaced while maintaining operation of at least one electrochemical unit 42. During normal operation 64 of the electrochemical system 16, the exchange port 26 and the further exchange port 56 are closed. In normal operation 64 of the electrochemical system 16, the main filter-side fluid outlet 58 and the main filter-side fluid inlet 60 of the actuating unit 24 are open. In normal operation 64, the further actuating unit 32 is at least partially, in particular completely, open. In normal operation 64, the fluid flow 40 passes completely through the main filter port 20.

[0028] The method 54 preferably includes an assembly step 66 in which the external maintenance device 30 is connected to the replacement ports 26, 56. The method 54 preferably includes an opening step 68 in which the replacement ports 26, 56 are opened without closing the main fluid line 18. The method 54 preferably includes an actuating phase 70. In the actuating phase 70, the main filter port 20 and the replacement ports 26, 56 are opened simultaneously. The fluid flow 40 is continuously diverted from the main filter port 20 to the replacement port 26 by means of the further actuating unit 32, in particular until the further actuating unit 32 is in a maximally closed position.The method 54 preferably includes a blocking step 72 in which the main filter-side fluid outlet 58 and the main filter-side fluid inlet 60 of the actuating unit 24 are closed, so that the fluid flow 40, in particular at this point at the latest, passes completely through the secondary filter 28. The method 54 preferably includes a replacement step 74 in which the main filter 20 is removed.

[0029] The method 54 preferably comprises a further replacement step 76 in which a new main filter 22 is connected to the main filter connection 20. The method 54 preferably comprises a further opening step 78 in which the replacement connections 26, 56 are opened without closing the bypass line 62. The method 54 preferably comprises a further adjustment phase 80. In the further adjustment phase 80, the main filter connection 20 and the replacement connections 26, 56 are opened simultaneously. The fluid flow 40 is continuously diverted from the replacement connection 26 to the main filter connection 20 by means of the further adjustment unit 32, in particular until the further adjustment unit 32 is in a maximum open position. The method 54 preferably comprises a further blocking step 82 in which the replacement connections 26, 56 are closed.The method 54 preferably includes a disassembly step 84 in which the external maintenance device 30 is removed from the replacement ports 26, 56.

[0030] Fig.4 shows a graph of the fluid flow 40 against time 86, showing a relative proportion 88 of the fluid flow 40 through the main filter connection 20 and a relative proportion 90 of the fluid flow 40 through the exchange connections 26, 56. During normal operation 64, the fluid flow 40 passes entirely through the main filter connection 20. During the exchange steps 74, 76, the fluid flow 40 passes entirely through the exchange connections 26, 56. During the adjustment phases 70, 80, the fluid flow 40 passes partially through the main filter connection 20 and through the exchange connections 26, 56, with the relative proportions 88, 90 being continuously shifted by the further adjustment unit 32 from the main filter connection 20 to the exchange connections 26, 56 or from the exchange connections 26, 56 to the main filter connection 20.

Claims

[1] Filter replacement device (10, 12, 14) for an electrochemical system (16), with at least one main fluid line (18), which comprises at least one main filter connection (20) for a fluidic connection with a main filter (22) of the electrochemical system (16), with at least one actuating unit (24) for blocking or opening the main filter connection (20) and with at least one replacement connection (26) for a fluidic connection of a secondary filter (28) of the electrochemical system (16) or an external maintenance device (30), characterized by a further adjusting unit (32) for continuously adjusting a flow resistance of the main filter (22). [2] Filter replacement device (10, 12, 14) according to claim 1, characterized by that the further actuating unit (32) comprises at least one continuous valve, in particular in the form of a throttle valve, in order to adapt the flow resistance [3] Filter replacement device (10, 12, 14) according to claim 1 or 2, characterized by that the further actuating unit (32) comprises at least one pressure regulator in order to adjust the flow resistance. [4] Filter replacement device (10, 12, 14) according to one of the preceding claims, characterized by that the further actuating unit (32) is arranged in the main fluid line (18) upstream of the main filter connection (20). [5] Electrochemical system (16) with at least one filter exchange device (10, 12, 14) according to one of the preceding claims and with at least one fuel processing unit (34), in particular a desulfurizer, connected to the filter exchange device (10). [6] Electrochemical system (16), in particular according to claim 5, with at least one, in particular further, filter exchange device (10, 12, 14) according to one of claims 1 to 4 and with at least one air treatment unit (36, 38) connected to the, in particular further, filter exchange device (12, 14). [7] Method (54) for operating an electrochemical system (16), in particular according to claim 5 or 6, which has a filter replacement device (10, 12, 14) according to one of claims 1 to 4, wherein in at least one method step for replacing the main filter (22) the flow resistance of the main fluid line (18) is continuously adjusted. [8] Method (54) according to claim 7, characterized by that in at least one method step for replacing the main filter (22), the main filter connection (20) and the replacement connection (26) are opened simultaneously. [9] Method (54) according to claim 8, characterized by in that in at least one method step for replacing the main filter (22), a fluid flow (40) is continuously diverted by means of the further actuating unit (32) from the main filter connection (20) to the replacement connection (26) or from the replacement connection (26) to the main filter connection (20). [10] Method (54) according to one of claims 7 to 9, characterized by that in at least one method step for replacing the main filter (22), a flow parameter of a fluid flow (40) through the filter replacement device (10, 12, 14) is regulated by means of the further actuating unit (32).

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