| 摘要 |
<p>The motorised valve comprises a housing having inlet and outlet ports and a valve within the housing for control of fluid flow between the ports. The valve comprises a poppet-valve member displaceable along a single axis between valve-open and valve-closed positions w.r.t. a seat fixed to the housing. A reversibly electric motor has a rotor on a shaft aligned with the axis and a stator mounted to the housing and concentric with the shaft. A first thread coacts between the housing and shaft with a first helical advance along the axis, a second thread coacting between the shaft and the poppet-valve member with a second helical advances being in the same direction but at differing pitch to develop differential-screw action in valve member displacement in response to electric motor drive of the shaft.</p> |
