Abstract

A low-powered electric to fluid valve unit includes a housing having a supply port connected to a pneumatic source and an output port connected to a pneumatic operator. A disc spring is clamped about the periphery within the housing. The peripheral portion is connected by a plurality of spring arms to a sealing disc located between the inner end of the supply port and an exhaust port. The disc spring is formed of a suitable spring material which may be of a magnetic or non-magnetic material. The disc is coated with a silicone rubber sealant. The housing is closed by an electromagnetic assembly threaded into the housing and having an E-shaped iron core having a coil wound about the central leg and connected to a signal source. The central core leg is formed with an exhaust opening and aligned with the spring disc. An iron pad is provided on the backside of the spring disc and is spaced slightly from the E-shaped iron core to define a working air gap. The pad provides a relatively large cross-sectional flux path for the magnetic field. The housing is formed of plastic components for ease of production. When the magnetic field starts movement of the spring, the air gap shortens and the spring snaps to close the exhaust port and open the supply port. When the magnetic field and holding force drops, the spring initiates return movement. The gap lengthens and creates a reverse snap action closing of the valve.