GB1131653A - Improvements in or relating to centrifuges - Google Patents

Abstract

1,131,653. Measuring rotational speed electrically. K. STROHMAIER. June 8, 1966, No.25536/66. Heading G1N. [Also in Divisions B2 and G4] In a centrifuge, means are provided to measure the "centrifugal action" by generating an electrical, quantity proportional to the square of the rotary speed of the rotor and forming the time integral of the square of the rotary speed of the rotor. As shown in Fig. 2, a generator 21 produces a voltage U 1 proportional to the speed of the rotor 3 which voltage is applied to a servomotor 22 driving rotary potentiometers 23, 24. Either potentiometer 23 has a linear characteristic and potentiometer 24 has a square characteristic or potentiometer 23 has a root characteristic and potentiometer 24 has a linear characteristic. The output of potentiometer 24 is fed to an integrating motor 25 which drives a counter 26. In alternative embodiments, the electrical quantity is generated by a dynamometer, Fig. 3 (not shown), or by two generators (41, 42) on a common shaft, Fig 4 (not shown), the output of one (41) being fed to the field windings of the other (42). In a further embodiment, described with reference to Fig. 1 (not shown), a pulse transmitter (4) delivers a certain number of pulses during each rotation of the rotor which are counted over defined time intervals and squared and the squares are then added in a cumulative register (10). When the centrifugal action has attained an adjustable predetermined value, a photographic device may be activated for detecting the concentration in the centrifuge cell or the driving motor may be switched off automatically.