Abstract: The present invention relates to system for measuring pressure and temperature based on change in the characteristic properties of a medium for ultrasound under the effect of pressure and temperature. The invention is based on two waveguides where geometry is adapted to the medium's characteristic properties for ultrasound such that only planar pressure waves are generated in the waveguides. The first of the waveguides is arranged for measuring temperature due to thermal expansion of the medium, where the medium is pressure-compensated by means of an internal compensator to prevent thermal pressure accumulation, and where measuring temperature is based on the medium's specific known characteristic data for ultrasound under the effect of temperature under constant pressure.

Abstract: Driving arrangement (11) for a pump, compressor or similar, adapted to provide alternating pressure in at least two chambers (27a, 27b, 27?, 27?), such as chambers of a pump or compressor, as result of a reciprocating movement of a bar element (23). The bar element is connected to two movable pressure chamber faces being pistons (21a, 21 b) or plungers having fluid connection to said chambers, which bar element (23) is reciprocally supported in a housing (19). The driving arrangement further comprises an electric motor (31) which is adapted to provide the reciprocating movement of the bar element (23). The bar element extends through the rotor (31b) of the electric motor (31). The electric motor is an electric rotary motor. The invention also relates to a pump assembly with a plurality of such driving arrangements.

Abstract: Driving arrangement (11) for a pump, compressor or similar, adapted to provide alternating pressure in at least two chambers (27a, 27b, 27?, 27?), such as chambers of a pump or compressor, as result of a reciprocating movement of a bar element (23). The bar element is connected to two movable pressure chamber faces being pistons (21a, 21 b) or plungers having fluid connection to said chambers, which bar element (23) is reciprocally supported in a housing (19). The driving arrangement further comprises an electric motor (31) which is adapted to provide the reciprocating movement of the bar element (23). The bar element extends through the rotor (31b) of the electric motor (31). The electric motor is an electric rotary motor. The invention also relates to a pump assembly with a plurality of such driving arrangements.