GB373261A - Improvements in or relating to electric means for testing or controlling material - Google Patents

Abstract

373,261. Testing fabrics, paper, &c. SIEMENS & HALSKE AKT.-GES., Siemensstadt, Berlin. Feb. 19, 1931, No. 5324. Convention date, May 10, 1930. [Classes 42 (ii) and 96.] For testing and controlling the thickness of rubber strips, paper, cellulose, textile fabrics, linoleum, &c. during manufacture, the material is passed between the plates of a teat condenser arranged in a Wheatstone bridge, the indicating voltage of which, after amplification, is applied to a rectifier bridge by means of which an indication is obtained on a direct-current instrument. The rectifier bridge consists of rectifiers D1, D2, Fig. 1, resistances Ra1, Ra2, and a direct-current instrument G. An auxiliary voltage Eh, which is high compared with the amplified indicating voltage Eb of the measuring bridge, is arranged so that the voltages Eh, Eb are added in the circuit of the rectifier D1 and subtracted in the circuit of the rectifier D2. The deflection of the instrument G is proportional to the voltage Eb. The auxiliary voltage Eh may be supplied through a phase-shifting potentiometer from the buzzer that supplies current to the measuring bridge. The rectifiers D1, D2 may be of the cuprous oxide type. The test condenser consists of a fixed plate 1, Fig. 4, supported on four porcelain insulators 2, and an upper earthed plate 3 which can be lifted and lowered by means of a lever 6. For controlling the manufacture of threads, these may be passed to and fro within the condenser between rolls. For use with material with a profiled surface, such as motor tyre strips, the condenser plates may be similarly profiled. The instrument G may be replaced by a relay controlling the roll pressure &c. Specification 363,308, [Group XXXVI], is referred to.