Liquid viscosity measuring and control system - adds viscous fluid to liquid in reservoir if measured viscosity is less than required

摘要

A pulsed sound signal provided by an oscillator (6) and transducer (3) passes through the liquid (2) in a reservoir (1). The time taken for the echo to return from the bottom of the reservoir is a measure of the viscosity. During the time between the start of the pulse and of the echo, a counter (11) counts clock pulses which are shown on a display as a measure of viscosity. This figure is then compared with the required viscosity setting on a switch bank (13), and entered in a memory (17). The comparator (14) opens a dosing valve (15) to inject a dose of very viscous liquid into the reservoir, and after mixing, the measurement is repeated. If the viscosity is unchanged, an alarm (18) operates. Temperature compensation is achieved by altering the clock frequency according to the signal from the temperature sensor (5).