Abstract: The present invention discloses a high-voltage electric field low-temperature plasma cold sterilization system circuit and apparatus, and belongs to the field of frequency converter power source circuit technologies. The present invention including a power source module, a voltage/current/power adjustment module, a switch module, and a transformer module. The power source module includes a single-phase frequency converter and a first-stage inductance.

Abstract: The invention relates to a water treatment apparatus based on plasma (ionized gas) discharge. In particular, the invention relates to the field of industrial and agricultural wastewater treatment. More particularly, the invention relates to disinfection of drinking water, and water in pools, spas and similar recreational water environments. The invention comprises a plasma reactor produces plasma discharge at low atmospheric pressure between liquid electrodes eliminating contamination of treated water by harmful nitrogen compounds and toxic substances due to electrode erosion.

Abstract: The application belongs to the technical field of water treatment, and relates to a biofilm electrochemical reactor for simultaneously removing nitrate nitrogen and trace organic matters in water.

Abstract: A high voltage discharge generating a plasma wave front is disposed within a headspace over an oil-containing liquid in order to create various chemical changes within the headspace, and ultimately within the liquid in order to inactivate various microbes, synthesize new chemicals, speed separation of a mixture, and aid in oil extraction. Such a discharge may be repeated at an optimum duration and duty-cycle to maximize the chemical effects of the non-equilibrium plasma at a substantially lower temperature than for an equilibrium plasma.

Abstract: A filter for filtering particulates from a fluid stream includes a filter element, a first end cap, a second end cap, and a wrap. The end caps are respectively secured to the ends of the filter element to form a fluid tight seal therebetween. At least one of the end caps defines an opening therethrough in fluid communication with the interior passage of the filter element. The wrap is in the form of a strip secured to at least the filter element. The wrap comprises a conductive layer comprising an electrically-conductive material. The wrap is wrapped around the filter element such that at least forty percent of the outer surface area is covered by the conductive layer.

Abstract: The present invention discloses a Fe—Al-based metal membrane and preparation method thereof, which relate to the technical field concerning gas-solid separation under high-temperature, low-pressure working conditions, and mainly address the defects of conventional metal filter elements in the prior art such as high filtration resistance and low flux under low-pressure working environments. The preparation method of the present invention comprises the steps of: stirring and defoaming a mixture composed of a Fe—Al-based metal powder and an organic-additive-added water-based solvent, thus obtaining a cast slurry; casting a uniform membrane layer on a metal substrate layer having a required thickness on a casting machine, and performing drying treatment on it, thus obtaining a membrane green body; and, placing the dried membrane green body in a sintering furnace for degreasing, sintering, and alloy phase ordering treatments, respectively, thus obtain a prepared Fe—Al-based metal membrane.

Abstract: In a method for extracting boron from feed water, a backwash operation is performed on a boron-saturated resin bed within a pressurized vessel, wherein the resin bed includes boron-selective resin for extracting boron from the feed water. An acid-based solution is injected into the boron-saturated resin bed, causing the boron to be released from the resin bed and into a boron solution. The boron solution is drained from the pressurized vessel into a holding tank. An acid displacement rinse operation is performed on the resin bed. A caustic solution is injected into the resin bed, the caustic solution recharging the resin bed for extracting the boron from the feed water. A caustic displacement rinse operation is performed for preparing the resin bed for receiving the feed water. Surplus water of the acid displacement rinse operation and the caustic displacement rinse operation are distributed to a source of the feed water.

Abstract: An electrochemical separation device includes a first electrode, a second electrode, and a cell stack including a plurality of sub-blocks each having alternating depleting compartments and concentrating compartments and each including frame and channel portions disposed between the first electrode and the second electrode. An internal seal formed of a first material is disposed between and in contact with the channel portions between adjacent sub-blocks in the cell stack and configured to prevent leakage between depleting compartments and concentrating compartments in the adjacent sub-blocks. An external seal formed of a second material having at least one material parameter different from the first material is disposed between and in contact with the frames of the adjacent sub-blocks in the cell stack and configured to prevent leakage from an internal volume of the electrochemical separation device to outside of the electrochemical separation device.

Abstract: The present application provides a method for extracting an extractable component from a feed liquid using a porous membrane. One embodiment of the method includes temperature-swing solvent extraction of water from saline water using a porous membrane.

Abstract: A multi-function lighting apparatus comprising a support structure, a light engine mounted on the structure, and a control unit controlling the light engine; the light engine comprising a first group of warm LEDs having color temperature ranging between 2000 and 2500 K and color rendering index ranging between 85 and 95; and a second group of cold LEDs having color temperature of at least 5000 K and color rendering index ranging between 65 and 75; the control unit being a two-channel driver control unit which controls independently the warm LEDs and the cold LEDs and is configured to control the light engine to emit white light with variable color temperature and luminous flux according to at least three different modes performing a lighting function, a plant maintenance function, and a sanification function respectively, as the color temperature and the luminous flux emitted by the light engine vary.

Abstract: Tandem electrodialysis (ED) cell systems and methods for using the tandem ED cell systems to extract and recover ions from ion-containing solutions are provided. The tandem ED cell systems are composed of ion-extraction and ion-recovery ED cells. A redox couple contained in the anolyte of the ion-extraction ED cell is different from a redox couple contained in the catholyte of the ion-extraction ED cell. The electrode reactions in the ion-extraction ED cell are reversed in the ion-recovery ED cell, with the anolyte and catholyte of the two ED cells swapped and continuously circulated. As a result, the redox species in the anolyte and catholyte of the two cells are never depleted, which allows for achieving ion extraction and ion recovery with the use of a minimal amount of the redox couples.

Abstract: Systems and methods for operating hydraulic fracturing units to pump fracturing fluid into a wellhead may include receiving a target flow rate and/or a target pressure for fracturing fluid supplied to the wellhead. The systems and methods may increase a flow rate from the hydraulic fracturing units according to a controlled increasing flow rate schedule toward the target flow rate and/or target pressure. When it has been determined the target flow rate and/or target pressure has been achieved, the systems and methods also may include operating the hydraulic fracturing units to maintain the target flow rate and/or target pressure. When the target flow rate has not been achieved, the systems and methods also may include generating notification signals, and/or when the target pressure has not been achieved, the systems and methods further may include operating the hydraulic fracturing units to maintain a maximum flow rate.

Abstract: A dryer cartridge for removal of water from a liquid is provided with a cartridge body having a receiving chamber and a cartridge body wall delimiting the receiving chamber at least in sections thereof, wherein the cartridge body wall allows the liquid to flow through. A drying agent is arranged in the receiving chamber. A connection head is provided that can fasten the dryer cartridge in an opening of a housing wall of a device for receiving the liquid. The connection head has a connection opening and the connection opening connects in fluid communication the receiving chamber to an environment of the cartridge body. A drying system is provided with a device for receiving the liquid and with the dryer cartridge that can be fastened to an opening of a housing wall of a device for receiving the liquid.

Abstract: Certain exemplary aspects of the present disclosure are directed towards an apparatus for electrostatic fluid filtration. The apparatus utilizing alternating positive and negative electrodes in conjunction with filter media there between to filter contaminants from a fluid flow.

Abstract: A magnet positioning system for positioning magnets inside pipes includes a first stackable paddle that includes slots for accepting magnets and a second stackable paddle that includes a metal component for attracting the magnets and securing the magnets in the slots when the paddles are stacked together. Once stacked together, the paddles are inserted into position inside a pipe and the metal component is removed to release the magnets which move toward, and attach to, the inside wall of the pipe. A fluid conduit is positioned between the magnets using a spacer and a fixing agent permanently secures the magnets, fluid conduit, and spacer in place.

Abstract: A desolidification process enables the isolation and extraction of solid additives from an unreacted petroleum residue stream. In a hydrocracking process that mixes a solid additive with a petroleum residue feedstock to convert the petroleum residue to higher-value distillates, the desolidification process enables the recovery of the unreacted petroleum residue for conversion to a saleable product. The desolidification process involves the mixture of one or more solvents with a slurry in which solids are integrated in the petroleum residue to generate a mixture having a decreased density and viscosity as compared to the slurry, which facilitates removal of the solids.

Abstract: In accordance with the principles of the present invention, a system and method for the management of the power applied to electrolytic cell is provided. The power management consists a constant current regulation, H-bridge control by pulse width modulation (PWM), and dimming control of the applied current to the electrolytic cell. The constant current regulation is an analog control that maintains the applied current at a user-defined current setpoint. The time scale of constant current regulation ranges from tenth of microseconds to milliseconds. The PWM control of the H-bridge allows for the instant adjustment of the electrolytic production output by turning the cell on and off; the time scale of the PWM control ranges from tenths of milliseconds to seconds. The dimming control allows the change of the applied constant current; the time scale of the dimming control ranges from milliseconds to hours and longer.

Abstract: A method for eliminating hydrocarbon fouling and reducing pumping power during hydrocarbon transportation. A dielectric layer covers the inner surface of a pipeline for transporting a water-hydrocarbon mixture. A proximity electrode is immersed in the water-hydrocarbon mixture, and an electrical voltage is applied across the dielectric layer. A buffer layer of water is formed on the dielectric layer since water is electrically attracted from the water-hydrocarbon mixture. This water layer, located between the dielectric layer and the water-hydrocarbon mixture, eliminates hydrocarbon fouling on the inner surface of the pipeline or any other internal surface that needs fouling protection. Alternatively, the dielectric layer covers an outer surface of the pipeline and is covered by an external conducting layer.

Abstract: A first wafer has a first stop layer deposited on a substrate, the substrate used to form a base support structure. A second wafer has a second stop layer deposited on a sacrificial substrate, and a filter layer deposited on the second stop layer. A rib layer is deposited on one of: the first stop layer of the first layer; or a third stop layer that is deposited over the filter layer. A rib pattern is formed in the rib layer. The first and second wafers are flip bonded such that the rib pattern is joined between the filter layer and the first stop layer. Elongated voids are formed within the filter layer. The base support structure is formed within the substrate of the first wafer such that there is a fluid flow path between the base support structure, the rib layer, and the elongated voids of the filter layer.

Abstract: An electrochemical separation device includes a first electrode, a second electrode, and a cell stack including a plurality of sub-blocks each having alternating depleting compartments and concentrating compartments and each including frame and channel portions disposed between the first electrode and the second electrode. An internal seal formed of a first material is disposed between and in contact with the channel portions between adjacent sub-blocks in the cell stack and configured to prevent leakage between depleting compartments and concentrating compartments in the adjacent sub-blocks. An external seal formed of a second material having at least one material parameter different from the first material is disposed between and in contact with the frames of the adjacent sub-blocks in the cell stack and configured to prevent leakage from an internal volume of the electrochemical separation device to outside of the electrochemical separation device.

Abstract: Apparatus and method for separating oil from water in produced oil without requiring large separation tanks in which the fluid is heated, using a simple, energy efficient separation process, are described. Centrifugal forces, by themselves, are not effective for completely separating a two-component fluid, especially when the densities of the fluids are similar, such as for heavy oil. By combining both primary and secondary acoustic forces, and taking advantage of centrifugal forces from fluid flow, such that acoustic radiation forces initiate the process of droplet accumulation, and contribute to droplet coalescence, centrifugal separation is enhanced.

Abstract: A method and system for performing biomolecule extraction are provided that use liquid-to-liquid extraction (LLE) in combination with an electrowetting on dielectric (EWOD) device to provide a biomolecule extraction solution that has high extraction efficiency and that is less costly and easier to use than current state of the art methods and systems. The system and method are well suited for, but not limited to, extraction of DNA, RNA and protein molecules.

Abstract: The present invention an apparatus and method of injecting a liquid borne sample into a field flow fractionator and a method of forming a top plate and spacer. In an embodiment, the field flow fractionation unit includes a top plate including a sample injection inlet port, a sample injection outlet port, and a spacer including a separation channel cavity defining at least a portion of the separation channel, a sample injection inlet cavity configured to be in fluid contact with the separation channel and located substantially beneath the sample injection inlet port, a sample injection outlet cavity configured to be in fluid contact with the separation channel and located substantially beneath the sample injection outlet port, such that the injection inlet and outlet paths are configured to define an injection channel that is essentially perpendicular to the length of the separation channel spanning the width of the separation channel cavity.

Abstract: An anti-counterfeiting mechanism for a filter element to specifically, and preferably uniquely, identify a filter with a conductive pattern or path of conductive materials preferably either embedded (thin film circuit) under the surface, or over molded on, a portion of the filter. The conductive materials are preferably positioned at the filter end cap. The resistance of the filter element is an identifier that is preferably associated with the OEM manufacturer's labeling (such as product number) and/or other branding of the component. This electrical resistance signature permits rapid identification of counterfeit filters.

Abstract: The invention relates to a method of performing an optical or electrical measurement in a sample of a disperse fluid, the sample comprising particles and a fluid. The method comprises the steps of: a) positioning the sample in a microfluidic cavity having a resonance frequency, b) subjecting the sample, in the cavity, to an acoustic standing wave configured for causing the particles to congregate in at least one first region of the cavity, thereby causing the fluid to occupy at least one second region of the cavity, wherein the frequency of the acoustic standing wave is varied between a frequency below the resonance frequency and a frequency above the resonance frequency, and c) performing an optical or electrical measurement in the fluid in at least one of the at least one second region of the cavity. Varying the frequency ensures reproducible results. The invention also relates to a system therefore and a method and system for measuring hematocrit.

Abstract: A universal chemical processor (UCP) including a reactor vessel with a main chamber, comprises inlets for feedstock, a fluidizing medium and reactants. The UCP further includes a reactive X-ray chemical processor (RXCP) having a large area hollow cylindrical cold cathode in the main chamber, a grid positioned concentrically with respect to the cathode, and an anode positioned concentrically with respect to the cathode and grid. In operation, when activated, the cathode of the RXCP emits electrodes onto the anode, which then emits X-rays into a radiation zone within the main chamber capable of ionizing feedstock and reactants, inducing chemical reactions, and sterilizing and decomposing organic materials within the radiation zone, and wherein, a fluidized bed is supported in the main chamber when the fluidizing medium and feedstock are supplied. The RXCP and the fluidized bed portions can be operated separately or in conjunction to achieve unanticipated results.

Abstract: A high salinity water purification system and process, including a forward osmosis system and a reverse osmosis or nanofiltration system. A concentrated brine of a zinc or iron complex combined with a salt or acid draws pure water across the FO membrane from the influent water. The diluted brine is pumped through a vessel holding an anionic adsorption media to remove the zinc or iron complex and the resultant brine is passed through the RO or nanofiltration system to obtain purified water and a concentrated brine stream. The adsorption media is regenerated by a rinse cycle using fresh water or water from the RO system, removing the zinc or iron complex adhered to the media. The resultant brine is stored and mixed with the output of the RO system.

Abstract: The present invention relates to a method and system for controlling disinfection in recirculating water systems and a method for retrofitting a recirculation system.

Abstract: An apparatus that functions as an influent multiple passage reactor adaptable to simultaneously carry out a series of functions including effluent contaminant dissociation and molecular oxidation utilizing electrolytic and catalytic reactions is disclosed. The apparatus comprises a concentric outside that may be constructed of an electrically conductive material to serve as a first electrode. A smaller second concentric electrode mounted inside the outside housing may serve as a first cathode, with a third but smaller concentric electrode mounted inside the first cathode serving as a second anode, with yet a fourth but even smaller concentric electrode mounted inside the second anode serving as a second cathode and thereof (with additional anode/cathodes further included as desired). Between each electrode an influent passageway is formed with the series of electrodes and passageways stabilized by two slotted end caps which also serve to seal the apparatus housing.

Abstract: An end cap for a fuel filter includes a metal body with a first surface opposite a second surface. A hole extends through the first surface and the second surface of the body. A metal spring is connected to the first surface of the metal body and extends at least partially over the hole.

Abstract: A stabilised aqueous formazin composition comprises 100 parts by weight water; up to 0.03 parts by weight formazin polymer; 0.4 to 5 parts by weight hexamethylenetetramine; and a buffer composition, wherein the buffer composition is adjusted to maintain a pH of the formazin solution in a range between 8.4 and 10. The stabilised formazin composition has a turbidity of 400 NTU or less. A diluent for preparing the stabilised formazin composition from a formazin stock composition is provided, wherein the diluent comprises hexamethylenetetramine in a concentration of between 4 and 50 g/l and a buffer composition adjusted to a pH of the diluent in a range of from 8.4 to 10.

Abstract: The present invention provides methods, compositions, and systems for distributing molecules and complexes into reaction sites. In particular, the methods, compositions, and systems of the present invention result in an active loading of molecules and complexes into reaction sites with improved efficiency over loading by passive diffusion methods alone.

Abstract: The present invention includes iterations of devices for absorbing water and hydrocarbons that accumulate in hydrocarbon handling and dispensing systems, fuel tanks, sumps, and other oil and hydrocarbon storage tanks, at gas stations and other locations such as ports, commercial trucking facilities, government installations, military bases, privately owned and commercial shipping vessels, and privately maintained fueling locations including trucking facilities, etc. Specialized versions of the devices can also clean up petroleum slicks on water surfaces—known as “sheen” or petroleum-contaminated water (PCW”), and other contaminants. The present invention can stop “phase separation”. Once they have absorbed water, most versions of the device can also be disposed of easily and economically compared to alternative disposal methods due to their extremely light weight and because they can be dehydrated before disposal.

Abstract: Wastewater containing scale components, organic substances, inorganic ions, and the like, such as human effluent, generated in a closed system space, such as a nuclear shelter, a hazardous shelter, a space station or a moon-Mars mission manned spacecraft, or a lunar base is efficiently treated by a simple structural apparatus, so that water is recovered. After a hardness component is removed from water to be treated, such as human effluent, by a softening device, and heat exchange is performed between softening treated water and electrolysis treated water by a heat exchanger, by a high-temperature and high-pressure electrolysis device, organic substances, urea, ammonia, and the like are removed by electrolysis performed under high-temperature and high-pressure conditions. After the electrolysis treated water is processed by a deaeration treatment using a deaeration membrane device, a desalting treatment is performed by acid/alkali manufacturing electrodialysis devices and provided in series at two stages.

Abstract: A filter cartridge for operatively coupling to an appliance interface to treat a fluid, such as water, being supplied to the appliance. The interface comprises a bypass valve for actuating the interface between a bypass mode in which the fluid flowing through the interface does not flow through the filter cartridge and a treatment mode in which the fluid flowing through the interface is directed through the filter cartridge for treatment by the filter cartridge. The filter cartridge comprises a cartridge housing having a first end and a second end and extending along a housing longitudinal axis through the first end and the second end. A filter media is contained within the cartridge housing between the first end and the second end. The filter cartridge also has a first end cap on the first end of the cartridge housing and a second end cap on the second end of the cartridge housing. A bypass valve actuator is attached to the cartridge housing and extends distally to an actuator distal end.

Abstract: A multi-layer liquid purification element includes a liquid-permeable top layer and a liquid-impermeable base layer. The base layer has a suction port for drawing-in liquid through the liquid purification element. At least the top layer and the base layer are connected to one another by a liquid-impermeable connection. At least one separate insert is disposed between the top layer and the base layer. A method for producing a liquid purification element, a device for extracting a liquid additive for exhaust-gas purification from a tank and a motor vehicle are also provided.

Abstract: Provided is a non-woven filtration material including a multilayer structure having a density gradient. The multilayer structure includes a coarse layer disposed at an upstream side of the non-woven filtration material and a dense layer disposed at a downstream side of the non-woven filtration material. The coarse layer and the dense layer are dry layers. The coarse layer contains 30% to 60% by weight of crimped conjugated fibers and contains 30% to 70% by weight of finer fibers. The crimped conjugated fibers have an average fiber diameter in a range from 15 ?m to 45 ?m. The finer fibers have an average fiber diameter that is in a range from 5 ?m to 20 ?m and smaller than the average fiber diameter of the conjugated fibers.

Abstract: The present disclosure is directed to ion generators and their enclosures that include a base, a non-linear wall projecting from the base, a top connected to the non-linear wall a top connected to the non-linear wall, wherein the base, the non-linear wall and the top form a closed space, and at least one ionizing element extending from the enclosure, wherein the at least one ionizing element is configured to receive a voltage capable of producing ions from a power source in the closed space.

Abstract: The object of the present invention is low-dimensional, primarily 2D folded structures of organic and/or inorganic substances and/or their agglomerates, which have folds and faces of irregular shape and exhibit high local electric field strength generated by surface charges on the said folds, faces and edges, and use thereof: as sorbents of organic particles (molecules, bacteria, viruses, proteins, antigens, endotoxins) and inorganic particles (metal ions, colloids); as an agent with wound healing and antibacterial activity; as an agent for tumor cell growth inhibition.

Abstract: A water treatment device includes: an insulating divider which divides a space inside a water tank into two treatment vessels adjacent to each other in a horizontal direction, and includes a current carrier which is able to energize water in the two treatment vessels; a treatment unit including a pair of electrodes, a power supply, and a power supply controller; a water supplier which supplies water to each of the treatment vessels; and a draining member which drains water from each of the treatment vessels. The treatment unit includes a detector which detects a level of water in each of the treatment vessels based on an index corresponding to a current value between the pair of electrodes.

Abstract: The present invention relates to ultrafiltration. In particular, the present invention provides nanoporous membranes having pores for generating in vitro and in vivo ultrafiltrate, devices and bioartificial organs utilizing such nanoporous membranes, and related methods (e.g., diagnostic methods, research methods, drug screening). The present invention further provides nanoporous membranes configured to avoid protein fouling with, for example, a polyethylene glycol surface coating.

Abstract: A system having improved trapping force for acoustophoresis is described where the trapping force is improved by manipulation of the frequency of the ultrasonic transducer. The transducer includes a ceramic crystal. The crystal may be directly exposed to fluid flow. The crystal may be air backed, resulting in a higher Q factor.

Abstract: Devices for separating materials from a host fluid are disclosed. The devices include an acoustic chamber having an inlet and an outlet. An ultrasonic transducer and reflector create a multi-dimensional acoustic standing wave in the acoustic chamber that traps the materials and permits a continuous separation of the materials from the host fluid. The materials and the host fluid can thus be separately collected. Multiple sets of trapping lines are generated by the acoustic standing wave, and the transducer is oriented to minimize cross-sectional area for straight vertical channels between the trapping lines.

Abstract: An acoustophoresis device made up of modular components is disclosed. Several modules are disclosed herein, including ultrasonic transducer modules, input/output modules, collection well modules, and various connector modules. These permit different systems to be constructed that have appropriate fluid dynamics for separation of particles, such as biological cells, from a fluid.

Abstract: A flow cytometer disinfection module is useful for disinfecting a sheath fluid in a flow cytometer. The module includes a flow cell and at least one UV-C and/or UV-B light source. The UV-C and/or UV-B light source is disposed about the cell and irradiates a sheath fluid passing through the cell.

Abstract: A method of detecting E-line loss in a disc stack centrifuge is provided, comprising: collecting data from at least one instrument associated with the centrifuge over a specific time period; calculating one or more indicators by comparing the collected data with expected values from a normally operating centrifuge, the indicators being indicative of a start of an E-line loss event; calculating the probability of E-line loss by applying weighted voting to the indicators to yield a probability value; and activating an alert upon determination that the probability value exceeds a threshold value.

Abstract: A suspension processing method using ultrasonic waves has problems in that movement of solids in liquid do not follow movement of the sound field. Accordingly, application to a field that requires a high suspension processing performance or a high flow rate process is difficult. In order to achieve the high suspension processing performance, a design of adopting a long and large oscillator and the like is required. A suspension processing device (30) of separating and concentrating a component of solids in suspension (1a) using ultrasonic waves, includes: at least one supply port (32) for supplying the suspension (1a) into the device; a channel (31) through which the suspension flows; at least two outlet ports (33 and 34) for discharging processed suspension (1a); an oscillator (35) for emitting ultrasonic waves; and a reflection plate (36) for reflecting the emitted ultrasonic waves.

Abstract: A component measuring apparatus includes a plurality of light sources having different Wavelengths. The component measuring apparatus also includes an irradiation unit that applies lights emitted from the plural light sources to a measurement object, and a light receiving unit that receives at least one of light having transmitted through the measurement object and light having been scattered from the measurement object. The component measuring apparatus further includes a measuring unit that measures intensity of the light received by the light receiving unit per wavelength.

Abstract: A vehicle fuel pump assembly, method of construction thereof, and a fuel tank assembly is provided. The fuel pump assembly includes a non-conductive plastic reservoir and an electrically powered fuel pump disposed in the reservoir. The fuel pump is configured to receive fuel through an inlet and to dispense fuel through an outlet. A fuel filter assembly having a non-conductive plastic housing is disposed in the reservoir and a coating of conductive material is bonded to the housing. A conductive lead is configured in electrical communication with the coating and is further configured for attachment to an electrical ground.

Abstract: A filter has a filter medium (10) during operation clears fluid, particularly in the form of hydraulic fluid. The filter medium (10) is made of a material such that the potential difference to the fluid to be cleaned is low. The parts of the filter medium (10) have different potentials with respect to each other and/or the fluid to be cleaned such that they cancel each other at least partially, specific dissipation is aspired, or a return of electric charge to the associated filter medium (10) is provided, using a charge equalization situation.