Flowmeter with thermostatically controlled Peltier element - permits setting of current through element according to temp. difference between probes fixed to two points of element

摘要

The flowmeter esp. for gases comprises a tube (2) contg. a thermo-sensitive element. This comprises a Peltier element (4) whose outer edges are insulated by discs (5, 6). A temp. probe (7, 8) is attached to each disc. These are connected in series with a voltage sensing device (12). The output signal from this, resulting from a temp. difference between the probes, controls a transistor or other variable resistance element (11). The variable resistance is in series with the Peltier element, a DC source (9), the secondary of a transformer (13) and an ammeter (10). The latter indicates the current in the element and is proportional to the velocity of flow through the tube. Since the Peltier coefficient is temp.-dependent, the element is thermostatically regulated by means of a Vanadium Oxide semi-conductor reference element (15).