Abstract: A process for producing hermetically sealed filters is disclosed. The process includes the steps of providing thermoplastic base and top filter parts and a section of filtration media, sandwiching the media between sections of the base and top filter parts under a compressive force, applying a rapidly repetitive force to at least one of the filter parts to cause movement between the parts and frictional welding of the parts, maintaining the compressive force after frictional welding to allow the melted portion of the parts to solidify and thereby form a fluid seal at the junction of the filter parts and at the junctions of the filtration media and each of the base and top filter parts. In one embodiment, the junction between the filter parts is the periphery of an automatic transmission filter, and the junction is hermetically sealed. A hermetically sealed automatic transmission filter is also disclosed.

Abstract: A fluid filter for use in a fluid system wherein fluid is forced through the filter by a suction source connected to the filter outlet is disclosed. In addition to a housing defining a volume, with an inlet and an outlet, and a filtration media envelope inside said volume, the filter further includes an envelope spacing means to support the envelope against collapse, and fluid flow spacing means between the housing and the envelope. In a preferred embodiment, the envelope spacing means comprises a grid assembly inside the envelope, connected to the housing inlet to maintain proper positioning.

Abstract: A check valve is disclosed made with a rotationally symetrical valve body with fluid inlet and outlet holes centered on the axis of symetry. A circular, flexible diaphragm is held in place inside the valve body by a mounting pin which extends through a hole in the diaphragm. The mounting pin and an opposing mounting pin receptical are supported by legs protruding inwardly from the inlet and outlet walls of the valve body and bridging over the inlet and outlet holes. The length of the legs determine the position of the diaphragm with respect to the inlet wall against which the diaphragm seals. Thus the opening pressure of the valve is dependant on the length of the legs.

Abstract: An improved low-profile inline filter unit comprising a housing unit and filter frame. The filter frame being adapted to fit substantially within the housing so that the filter frame may be sonically welded to the housing unit. The housing unit and filter frame cooperating to provide a visible indicator for determining whether an internal hermetic seal is present between the housing unit and filter frame.

Abstract: An improved low-profile inline fluid filter (10), for IV sets and the like, comprises only two discrete units: a shell unit (11) and a screen unit (12). The screen unit (12) is adapted to fit substantially within the shell unit (11) such that the screen unit (12) and the shell unit (11) are connected to each other at both ends.