GB684935A - Method of and apparatus for measuring, recording or controlling viscosities and plotting flow curves - Google Patents

Abstract

684,935. Measuring viscosity electrically. ERLENBACH, M., and SIEGLITZ, A. March 30, 1951 [March 30, 1950], No. 7471/51. Class 40 (i) [Also in Groups XXXV and XL(b)] Apparatus for measuring the viscosity of a fluid comprises a cylinder 7 supported by a torsion wire 6, in the fluid to be tested, contained in a vessel 1 rotated by a motor 5, the resultant angular displacement of the inner cylinder 7 being sensed by, an optical system including a photo-electric cell 12 whose energization causes a servo-motor 22 to rotate a torsion head 25 to bring the cylinder 7 back to its original position, the amount of rotation being indicated on a scale 29. The temperature of the test fluid is maintained constant by a temperature control jacket 2. The photo-electric system comprises a mirror 9, attached to the cylinder 7, which reflects a proportion of the light from a lamp 10 onto a photo-cell 12, so that with rotation of cylinder 7 and mirror 9 the amount of light falling on the cell 12 is varied, thus altering the current in the anode circuit of a valve 13, affecting the energization of the winding 15 of a relay whose contacts 16, 17, 18 close the circuit of a servo-motor 22 to drive the torsion head 25 to restore the position of the mirror 9 and cylinder 7. The torsion head 25 may also be connected to a transmitter 27 feeding a remote indicator 28. The contacts 16, 17, 18 may be duplicated to provide fast and slow contact of the servo-motor 22. In a modification the rotating vessel 1 may be driven at varying speeds, the recorder indicating the relationship between viscosity and angular speed, by a recording arrangement in which the recording drum is moved in accordance with the viscosity, and the pen in accordance with the speed.