A filter system for filtering a fluid has a filter housing with filter housing head module and housing cover. The filter housing accommodates a filter element with raw side and clean side. A fluid inlet is in fluid connection with the raw side of the filter element. A fluid outlet is in fluid connection with the clean side of the filter element. The filter housing head module has a tube section as a main channel connecting the clean side of the filter element to the fluid outlet when the housing cover is attached to the filter housing head module. The tube section projects into the clean side of the filter element and has a ball valve seat of a ball valve for closing or opening the main channel. The filter housing head module has a pump chamber of a pump as a bypass channel bypassing the ball valve seat.

An oil pressure supply device supplies, to an oil chamber, an oil pressure generated by suctioning oil from an oil source with an oil pump. The oil pressure supply device includes a first oil passage connected to a suction side of the oil pump; a first check valve provided in the first oil passage and configured to close the first oil passage and prevent oil from moving to the oil source side when the oil pump is stopped; a second oil passage connected to a discharge side of the oil pump; and a second check valve provided in the second oil passage and configured to close the second oil passage and prevent oil from moving to the oil pump side when the oil pump is stopped. When the oil pump is stopped, the second check valve closes the second oil passage earlier than the first check valve closes the first oil passage.

An oil pressure supply device supplies, to an oil chamber, an oil pressure generated by suctioning oil from an oil source with an oil pump. The oil pressure supply device includes a first oil passage connected to a suction side of the oil pump; a first check valve provided in the first oil passage and configured to close the first oil passage and prevent oil from moving to the oil source side when the oil pump is stopped; a second oil passage connected to a discharge side of the oil pump; and a second check valve provided in the second oil passage and configured to close the second oil passage and prevent oil from moving to the oil pump side when the oil pump is stopped. When the oil pump is stopped, the second check valve closes the second oil passage earlier than the first check valve closes the first oil passage.

A filter cartridge with flow travelling from inside to outside with a flow path in a bottom end cap to enter the cartridge has an anti-drain back valve to prevent cross-contamination to the clean side of the system during filter change-out. The anti-drain back valve moves away from the bottom end cap to allow inlet flow into the cartridge during filtering operation, and when flow ceases, the valve settles to the bottom of the cartridge to plug the flow path during service.

A filter cartridge with flow travelling from inside to outside with a flow path in a bottom end cap to enter the cartridge has an anti-drain back valve to prevent cross-contamination to the clean side of the system during filter change-out. The anti-drain back valve moves away from the bottom end cap to allow inlet flow into the cartridge during filtering operation, and when flow ceases, the valve settles to the bottom of the cartridge to plug the flow path during service.

Contaminants are removed from a liquid (12) in a storage vessel (14), by using a working liquid to varying the volume of a working cavity (44) sequentially inside a working vessel (16) and using the variations in the volume of the working cavity (44) to vary the volume of a suction cavity (20). The working cavity (44) is defined in a working vessel (18) and the suction cavity (20) is defined in a suction vessel (26) and the vessels (16, 18) are configured so that the volumes of their internal cavities (20, 44) are inter-dependent. Using non-return mechanisms (26, 36) to ensure one-way from the storage vessel (14) via the suction cavity (20) to a filter (28) and back to the storage vessel (14).

Contaminants are removed from a liquid (12) in a storage vessel (14), by using a working liquid to varying the volume of a working cavity (44) sequentially inside a working vessel (16) and using the variations in the volume of the working cavity (44) to vary the volume of a suction cavity (20). The working cavity (44) is defined in a working vessel (18) and the suction cavity (20) is defined in a suction vessel (26) and the vessels (16, 18) are configured so that the volumes of their internal cavities (20, 44) are inter-dependent. Using non-return mechanisms (26, 36) to ensure one-way from the storage vessel (14) via the suction cavity (20) to a filter (28) and back to the storage vessel (14).

A filter assembly includes a ring of filter media, a first end cap, a second end cap, a first seal, and a second seal. The first end cap is coupled to a first end of the filter media. The second end cap is coupled to a second end of the filter media and includes (i) a radially extending portion having a first opening and (ii) a first axially extending portion having a stepped ledge defining a first inner diameter. The first seal is supported by the second end cap and includes a second opening defining a second inner diameter that is less than the first inner diameter. The second seal is supported by the second end cap and includes a third opening defining a third inner diameter that is greater than the first and second inner diameters. The stepped ledge is disposed between the first seal and the second seal.

A water purifier structure includes a container assembly and a buffer unit mounted in the container assembly. The container assembly includes a housing and a cap unit. The housing has a first receiving section and a second receiving section. The second receiving section of the housing is provided with a retaining portion. The buffer unit is mounted in the second receiving section of the housing and includes a positioning ring secured in the retaining portion of the housing, and a cushioning member mounted in the positioning ring. The cushioning member is elastically movable in the positioning ring. When the cushioning member is compressed by a force, the cushioning member is contracted and elastically deformed toward the second receiving section of the housing, to form a buffering force.

A filter device may include a filter housing with a filter housing pot and a cover screwable onto the filter housing pot, and an annular filter element arranged in the filter housing and having an axially protruding pin for closing a run-off channel. The annular filter element may be connected to the cover via a first thread, which may have a dome protruding centrally and axially from an upper end disc of the annular filter element. The first thread may be designed running counter to a second thread arranged between the filter housing pot and the cover.