Abstract: The present invention is the use of stellite material for all contact surfaces between moving parts and a metering pump pumping silver photographic emulsion. All parts that are in contact with the solutions containing silver made of stellite will prevent failure of rotating assemblies due to metallic silver plateout between rotating parts. Prior art pumps exhibited silver plateout after very few hours of operation.

Abstract: A sealed filter unit is provided having end caps which engage fluid connectors which are in turn connectable to external piping conveying fluid through the filter and which provide a preliminary seal upon mounting the filter unit in the filter holder. The filter unit assures that all fluid passing through the unit is filtered in a single pass without wetting the filter holder into which the filter unit is mounted via the fluid connectors. The filter holder allows rapid and reliable insertion and removal of the filter unit to and from the filter holder. The filter holder will accept various sizes of filter units as required by the process. In the preferred embodiment, the fluid connectors are a part of the filter holder. In the absence of fluid pressure, the filter unit can be manually removed from the filter holder fluid connectors for replacement of the filter unit.

Abstract: Disclosed herein is a housing for a disk of filter material. The housing includes two disk-shaped parts. One of the housing parts includes a radially-inwardly facing cylindrical surface for locating a filter disk. The other housing part includes a radially-outwardly facing cylindrical surface. The two cylindrical surfaces telescope together during assembly and serve to locate the housing parts relative to one another in directions parallel to the general plane of a filter disk in the housing. The radially inwardly facing cylindrical surface serves to locate a filter disk during assemble. Radially inwardly of the cylindrical surfaces is resilient means for engaging and squeezing the annular peripheral margin of the filter disk for at least partially preventing material being filtered passing radially outwardly of the filter disk and for totally preventing material bypassing the filter disk.