Flowmeter with high accuracy temp. compensation - has by=pass choke with piston displaced by expansion element

摘要

A flow throughput meter has a liquid-driven impeller driving a counter mechanism. The impeller is mounted in a housing between an inlet and outlet also connected by a bypass with a variable choke. Temp. compensation is provided using a single measurement device for liquids of different temp. giving a high degree of constant accuracy. In addition to the choke (12) the bypass (7) contains a thermal expansion element (19) which varies the bypass cross-section with temp. The choke consists of a threaded bolt (12) with a transverse hole of cross-section equal to that of the bypass. A control piston (16) in a longitudinally drilled hole (15) in the bolt has a cross-section corresp. to the bypass cross-section. It is moved under the influence of the thermal expansion element.