Temp.-dependent expansion material element actuator - controls working piston position, e.g. for valve, by heating element in electrical circuit and mounted on element

摘要

The control heating element (4) comprises at least one resistor of positive temp. coefft. and at least another one of linear behaviour, all connected in series. The working piston (2) moves (3) in dependence on the temp. of the element (1) of expansion material. An electrical heating element (4) is mounted on the latter (1) and is in the current circuit of a voltage supply (5). This circuit can be closed or broken by a switch (6). A variable resistor (7) sets the level of current for the heating element. As soon as current flows through the latter it heats the element (1) which pushes the piston out to operate e.g. a valve. USE/ADVANTAGE - Radiator valve; ventilation flap in building; heating flap; slide valve. Rapid response. Gives definite displacement of working piston without risk of overheating expansion material element.