High sensitivity liquid thermometer - has bulb connected to triple valve giving access to levelling reservoir and capillary measuring tube

摘要

A thermometer is designed to be sensitive to small changes is temperature. It has an elongated probe body the lower end of which forms a chamber containing a fluid which expands with heat. There is a pipe (15) leading from the probe body to a valve (18). This valve is a triple valve. Fluid forced up the pipe may flow into a reservoir (16) or a bypass tube (26). This tube acts as a measuring tube and the fluid may be seen rising relative to the level in the reservoir. The bypass tube may be made of glass or plastics.