Importance

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Abstract

An actuator for an axial flow control valve for operation at high speeds comprises an axially symmetrical plunger armature prebiased against a valve seat in a normally closed position, the plunger having a head portion of increased diameter and a rod portion, the rod portion being slidably received within a central passage of a bobbin, and axially spaced from a pole piece. The valve actuator further comprises a cylindrical housing encasing in coil wound around the bobbin with a central passage configured to allow the flow of fluid around the armature and pole piece when the valve is open, the pole piece, armature housing and end piece being magnetically permeable and the magnetic circuit being completed by a similarly magnetically permeable washer fitted into the housing having an internal opening diameter greater than the diameter of the plunger rod section and less than the diameter of the plunger head section positioned on the bobbin side of the plunger head. Upon excitation of the coil a magnetic circuit is completed, comprising two air gaps, the first being the conventional air gap between the pole piece face and the opposing face of the plunger rod section end, and the second air gap being between the axially opposing surfaces of the washer and the plunger head whereby both air gaps act in an axial direction to produce a high ratio of axial force to mass of the plunger armature creating high speed operation.

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First Claim