Piston valve with annular passages

Apparatus comprising:

• a fluid control valve configured for use in a connection with an enclosed tank, wherein the tank is operable to oxidize oxidizable contaminants in liquid and to filter such liquid,
• wherein the tank includes an upper area that houses an air pocket, and a tube that extends in the tank and includes a tube opening in the upper area,
• wherein the tank includes a lower area, wherein the lower area houses filter media, and a lower tank fluid port in the lower area below the filter media,
• wherein the fluid control valve includes
• a body,
• an axially extending cylindrical cavity within the body,
• a plurality of annular flow cavities in surrounding relation of the cylindrical cavity,
• a cylindrical piston axially movable in the cavity,
• a plurality of annular resilient seals in operative connection with the piston and the cavity,
• a plurality of fluid passages in the body, wherein axial positioning of the piston is operative to cause such passages to be fluidly connected and fluidly separated within the valve,
• wherein selectively positioning the piston relative to the flow cavities in a filter service position is operative to cause
• untreated liquid to be received into the valve through an untreated liquid port,
• untreated liquid to be passed through at least one valve passage so as to be caused to be passed through the tube and into an air pocket in an upper area of the tank,
• filtered liquid to be received from the lower tank fluid port and passed through at least one valve passage to a filtered liquid outlet port of the valve, wherein in the filter service position the plurality of seals remain continuously wetted with the liquid and are not exposed to air.

Apparatus comprising:

• a control valve configured for use in connection with a liquid treatment tank,
• the control valve including:
• a valve body, wherein the valve body houses a valve interior area, the valve interior area including
• a longitudinally elongated cylindrical bore,
• a piston, wherein the piston is selectively longitudinally movable within the bore,
• a plurality of annular flow cavities, wherein at least one of the piston or the valve body includes the plurality of annular flow cavities,
• wherein the valve body further includes
• a plurality of fluid ports, wherein the ports are in fluid connection with the bore,
• wherein the ports include
• an untreated liquid port, wherein the untreated liquid port is configured to be operatively connected to a source of untreated liquid at elevated pressure, wherein the untreated liquid includes oxidizable contaminants,
• a treated liquid port, wherein the treated liquid port is configured to be operatively connected to at least one treated liquid use device,
• a drain port, wherein the drain port is configured to be operatively connected to a waste liquid drain,
• a further valve outlet port,
• a first tank port, wherein the first tank port is configured to be operatively connected to a first area of the tank disposed on a first side of a liquid treatment material in the tank,
• a second tank port, wherein the second tank port is configured to be operatively connected to a second area of the tank disposed on a second side of the liquid treatment material in the tank,
• wherein selected ports are enabled to be in fluid connection through the flow cavities, responsive at least in part to longitudinal positioning of the piston in the bore,
• wherein the tank includes
• an enclosed tank interior area, wherein the tank interior area includes
• an upper area, wherein the upper area is configured to house an air pocket,
• a lower area, wherein liquid treatment material is positioned in the lower area,
• a tube, wherein the tube extends vertically between the upper and lower areas, wherein the tube includes
• a tube interior area,
• a tube opening to the tube interior area, wherein the tube opening is in the upper area,
• a lower tank fluid port, wherein the lower tank fluid port is in fluid connection with the tank interior area outside the tube and below a level of the liquid treatment material, and wherein the lower tank fluid port is fluidly connected with the second tank port,
• a tube fluid port, wherein the tube fluid port is fluidly connected to the tube interior area and the first tank port,
• an air introduction nozzle, wherein the air introduction nozzle is in fluid connection with
• the further valve outlet port,
• the tube fluid port,
• an air source including ambient air,
• a valve controller, wherein the valve controller is operable to selectively move the piston to a plurality of longitudinal positions, wherein
• in a first longitudinal position the untreated liquid port and the first tank port and the second tank port and the treated liquid port are in fluid connection through the valve, whereby the valve is in a filter service condition and untreated liquid is treated by passing through the air pocket and the liquid treatment material and delivered from the valve through treated liquid port, and wherein in the filter service condition the valve interior area remains in a wetted condition and is not exposed to air,
• and wherein the valve controller is selectively operative to cause
• untreated liquid from the untreated liquid port to be passed from the valve interior area and through the further valve outlet port to the air introduction nozzle, and
• air to be introduced into the untreated liquid through the air introduction nozzle and the air passed into the upper area of the tank.

Apparatus comprising:

• a fluid control valve configured for use in connection with an enclosed tank, wherein the tank is operable to oxidize oxidizable contaminants in liquid and to filter such liquid,
• wherein the tank includes an upper area that houses an air pocket, and a tube that extends in the tank and includes a tube opening in the upper area,
• wherein the tank includes a lower area, wherein the lower area houses filter media, and a lower tank fluid port in the lower area below the filter media,
• wherein the fluid control valve includes
• a body,
• a plurality of fluid passages in the body,
• at least one movable valve element that is movable within the body,
• a plurality of resilient seals within the body, wherein at least one seal is in operative connection with the at least one movable valve element,
• wherein movement of the at least one valve element within the body is operative to cause such fluid passages to be selectively fluidly connected and fluidly separated within the valve,
• wherein selectively positioning the at least one valve element relative to the at least one seal in a filter service position is operative to cause
• untreated liquid to be received into the valve through an untreated liquid port,
• untreated liquid to be passed through at least one fluid passage so as to be caused to be passed through the tube and into an air pocket in an upper area of the tank,
• filtered liquid to be received from the lower tank fluid port and passed through at least one fluid passage to a filtered liquid outlet port of the valve, wherein in the filter service position the at least one seal within the body remains continuously wetted with the liquid and is not exposed to air.