Price meter for hot water supply - is operated by circuit connected to temp. sensor adjacent to throttle in supply to tap

摘要

The method of determining the cost of hot water drawn off from a hot water supply uses an electronic measuring device (8) at each tap (3). Positioned behind the body of the tap is a temperature transducer (6), and immediately behind this point, a throttle (1) made of PTFE is housed inside the pipe. The temperature transducer gives a signal which varies linearly with the change in temperature and is connected to a circuit with a switch operated by a relay. When a determined temp. level is reached, a measuring circuit is operated which operates an indicator showing the cost. The signal from the transducer is applied to a resistance giving a voltage drop is operate a zener diode and transistor controlling the relay.