calorimetric device for measuring the quantity of heat ceded by a fluid which has a heat exchanger

摘要

This measures the quantity of heat dissipated by a fluid to a heat exchanger. It has a flow meter, one heat sensor each in the feed and return sides of the water circulation in the heat exchanger, a saw-tooth voltage generator (40), comparators (32, 33), and a counting clock generator (50). The heat sensors, which are constructed as linear measuring shunts (5, 9), are fed respectively from a constant-current source (17, 23), it being possible to switch the inputs (30, 31) of the comparators (32, 33) jointly to calibration resistors (22, 28). A logic element is driven in accordance with the difference between the voltages transmitted by the heat sensors and the saw-tooth voltage. In one circuit state of the logic element, the voltage pulses of the counting clock generator (50) are fed for display to a counting mechanism (47), the constancy of the currents through the heat sensors being guaranteed for the duration of a measurement period by being automatically calibrated at adjustable intervals by means of a control loop (50, 52, 55, 58). This device renders it possible to determine precisely a quantity of heat dissipated, e.g. in district heating, or a quantity of heat absorbed by a consumer. IMAGE