Abstract: A multiport valve is taught for regulating flow of liquid therethrough originating from at least two sources. The valve includes a three cylindrical valve chambers each having a piston residing therein such that through actuation of the pistons flow through each valve chamber can be permitted or stopped independently. There is an inlet port that tangentially intercepts the first cylindrical valve chamber and there is an outlet port that tangentially intercepts an intermediate cylindrical valve chamber. The design of the three valve chambers and the inlet and outlet ports to the valve chambers effectively eliminates any bubble traps in the valve and allows bubbles to be swept from the valve chambers.

Abstract: A method and apparatus for switching a supply to a process from a first vessel to a second vessel. Liquid is flowed from the first vessel through a first outlet conduit through a vessel selection valve, including first and second switch valves, to the process. A conductivity sensor measures the conductivity level of the liquid in the first outlet conduit at a point upstream of the selection valve and a computer compares the conductivity level to a predetermined range. The computer signals an isolation valve, in a second outlet conduit from the second vessel, to open and allow liquid to displace air in the second outlet conduit from the second vessel to the selection valve. The computer determines a delay to allow liquid below the first conductivity sensor to reach the first switch valve, then closes the first switch valve and opens the second switch valve.

Abstract: A method and apparatus is taught for switching supply to a downstream process from a first vessel containing a first batch of a liquid composition to a second vessel containing a second batch of the liquid composition. The liquid is flowed from the first vessel through a first outlet conduit from the first vessel and through a vessel selection valve to the downstream process, the vessel selection valve including a first switch valve and a second switch valve. A conductivity sensor measures the conductivity level of the liquid composition at a point in the outlet conduit from the first vessel before the vessel selection valve and a computer compares the conductivity level to a predetermined range. The computer signals a vessel isolation valve in the second outlet conduit from the second vessel to open thereby displacing air in the second outlet conduit and filling the second outlet conduit with the liquid composition from the second vessel to the vessel selection valve.

Abstract: A multiport valve is taught for regulating flow of liquid therethrough originating from at least two sources. The valve includes a three cylindrical valve chambers each having a piston residing therein such that through actuation of the pistons flow through each valve chamber can be permitted or stopped independently. There is an inlet port that tangentially intercepts the first cylindrical valve chamber and there is an outlet port that tangentially intercepts an intermediate cylindrical valve chamber. The design of the three valve chambers and the inlet and outlet ports to the valve chambers effectively eliminates any bubble traps in the valve and allows bubbles to be swept from the valve chambers.

Abstract: A method for switching filters on-line while continuously supplying a fluid to a downstream operation such as a photographic product coating device comprising transmitting the fluid to a filter selection valve having a first flow path therethrough to a first filter and a second flow path therethrough to a second filter; flowing the fluid through the first flow path and through the first filter to a filter diverter valve having a first fluid from the first filter to the downstream operation, a second fluid path from the second filter to the downstream operation, a third fluid path from the first filter to a drain, and a fourth fluid path from the second filter to the drain; directing the fluid through the first fluid path; determining when the first filter will soon become inoperable; opening the second flow path through the filter selection valve and opening the fourth fluid path through the filter diverter valve; closing the fourth fluid path after the fluid has flowed through the second filter but prior to