| 摘要 |
<p>Position measurement device (11), a linear operating differential transformer, provides position signal, according to position of control element (5) or component displaced by control element. Control circuitry controls heating of ohmic resistance (H) according to control signal and position signal. Ohmic resistance (H) is next to thermal stretch material (3). Heating alters temperature and volume of stretch material, and control element (5) is displaced and opening location of valve. Position measurement device (11), a linear operating differential transformer, provides position signal, according to position of control element (5) or component displaced by control element. Control circuitry controls heating according to control signal and position signal. Transformer has primary winding and two phase opposed secondary windings connected with support (1) and core connected with control element or with component displaceable by control element. Deviation of ambient temperature from nominal value is used to determine nominal valve lift, corresponding to water level needed to reduce value. Actual valve lift is registered and regulated according to current feed to heating resistor which heats wax shell and causes movement of valve pin.</p> |
