GB1235589A - Improvements relating to sensing when viscosity of a fluid has risen to a given level - Google Patents

Abstract

1,235,589. Testing viscosity. BAXTER LABORATORIES Inc. June 16, 1969 [June 17, 1968], No. 30360/69. Heading G1S. [Also in Division G4] In order to measure the time taken for the viscosity of a sample Fig. 1 to rise to a predetermined level after a reagent is added, a spherical ball 18 is magnetically 14, 16 suspended in the sample, the sample is reciprocated 12 in a vertical direction, and constant frequency clock-pulses are counted from the instant of adding the reagent until the viscosity has risen to the predetermined level, this being detected photo-electrically 20, 22 (or by inductive means, not described). As described the sample is blood to which thromboplastin has already been added, and the reagent is calcium chloride. In operation the sample, containing the ball, is placed in a well 40, Fig.2, of atemperature controlled block 30. The ball then rises to the level of the magnet 14, 16 and blocks the light path 20, 22, Figs.2, 6, thereby energizing a relay K1 (shown de-energized) to start a reciprocating drive motor 44 and a 10c/s clock-pulse generator motor 108 details Fig. 5 (not shown). Addition of a measured quantity of reagent is effected by depressing a cylinder 54, Fig.2, to thereby close a switch 66, Figs.2, 6, and energize a second relay K2, which holds over its lower contact and allows clock-pulses to pass over its upper contacts to a counter 250. Eventually, when the viscosity has risen, the ball is dragged from its position between the magnets 14, 16, the light path 20, 22 is cleared, and relay K1 is de-energized to break the hold circuit for relay K2 and the counting is stopped. Dimensions and components of a preferred embodiment are given in the Specification.