Abstract: A pump includes a pump housing (10, 11, 20) that has a circular-cylindrical piston chamber (14), a rotatable and axially movable circular-cylindrical pump piston (40) in said chamber, means (30, 43) for rotationally driving the piston in the chamber, and means (11, 41; 13, 42; 67, 68) for imparting to the piston guided axially reciprocating movement in the piston chamber through the medium of piston rotation, wherein the pump includes lines and valve means for permitting one-way suction and one-way propulsion of pump fluid respectively into and out of the pump chambers between the ends of the piston chamber and the respective adjacent end of the piston. The means for imparting axial reciprocating movement to the piston are adapted to cause the piston to move axially at a constant speed at a constant rotational speed of the piston, at least during the expulsion of pump fluid.

Abstract: An amplifier including a first transistor whose emmiter is connected to an amplifier output and whose collector is connected to a first of two current supply terminals, with the base of the first transistor being connected to an input. A constant load circuit is connected between the emitter of the first transistor and the second current supply terminal. The constant load circuit is adapted to ensure that the current through the first transistor will always exceed a lowest value, so that the first transistor will always lie in a limited, generally linear area of its working curve.

Abstract: A bubble detector includes a conduit (1) through which a first fluid having a first refractive index is intended to flow, a light source (3) which directs a light beam (4; 41, 42) through a transparent conduit wall-part (12), through the conduit cavity and out through a second transparent conduit wall-part, and a detector means (5; 51, 52, 53) adapted to receive the light beam (4, 41) after the beam has passed through the conduit and the first fluid therein. The two opposing transparent wall-parts (12, 11) of the conduit (1) are trans-illuminated by the light beam and are essentially planar and parallel. The light source (3) is adapted to direct the beam (4) at an oblique angle (.alpha.) to the proximal transparent wall-part (12) of the conduit (1), so that the light source will be broken into different paths (41, 42) depending on whether the beam passes the first fluid or a second conduit-carried fluid having a different refractive index, such as a bubble.