GB1120925A - Improvements in and relating to viscosimeter apparatus - Google Patents

Abstract

1,120,925. Electric motors. CONTRAVES A.G. 12 July, 1967 [19 Aug., 1966],No. 32077/67. Heading H2A. [Also in Divisions G1 and G3] The viscosity of a liquid is determined by rotating a cup 3 (Fig. 1) in the liquid at a constant speed and measuring the back torque on the stator. The driving force is supplied by an A.C. synchronous motor comprising stator windings 21, 23, ferromagnetic stator assembly 231-2-3, and rotor 26. The windings 21, 23 are mounted on a fixed housing 10. The flux produced when energized passes through gaps L 1 , L 2 , L 3 to members 231, 232, 233 which are carried by a shaft 23 attached to one end of a spiral spring 25. Located Centrally is the rotor 26 on a shaft 260 carrying at its lower end a permanent magnet 27 in a non-magnetic sheld 11 through which it magnetically couples with magnets 31 on a cup 3 which rotates with the rotor 26 about a bearing 32 at the end of a pin 12 protruding from the shield 11. The torque required to maintain the cup 3 rotating at synchronous speed is reflected in the stator assembly and produces an angular displacement of shaft 23 against spring 25 indicative of the viscosity of the liquid which is indicated by a pointer 5 attached to the shaft, or by an electrical transducer. In one embodiment (Figs. 3, 4, not shown) shaft 23 is associated with a followup switch arrangement to maintain the viscosity of the liquid at a predetermined value, by controlling the preheating or a valve of a diluent pipe.