Abstract: The present differential pressure limiting valve is constructed with an axially movable valve body having hydrostatic bearings including bearing shafts, whereby the bearing shafts are connected to opposite sides of said valve body in axial alignment. Normally the valve body is biased against the valve seat by an adjustable closing spring acting on the bearing shaft or valve body opposite the valve seat to close the valve. In addition, the face end of the bearing shaft opposite the valve seat may be loaded by a pressure medium. The respective diameters of the bearings may differ. However, the effective cross-sections of the valve body are preferally equal on both sides of the valve seat.

Abstract: The present mechanical chucking device especially for a testing apparatus, has a friction reducing layer interposed between the clamping members and a base plate and another friction reducing layer interposed between the base plate and securing elements for the clamping members, whereby said clamping members may slide within a given range along the base plate without having to release the securing elements holding said clamping members to the base plate. The clamping members are driven by a spindle movably held in a guide block on the base plate which allows an exact concentric clamping of the sample.

Abstract: The leakage flow of a pressurized medium in gap type seals is controlled by a suction device at the sealing location of the gap seal. The suction device comprises a jet pump. The jet pump is driven by the pressurized medium in the gap seal or by an externally supplied fluid medium.