Abstract: A fluid signal comparator includes a flexible diaphragm clamped within a housing and defining a signal input chamber coupled to a signal source and an input/output chamber connected to an air supply and to a load. A leakport orifice unit includes a centrally located nozzle having a planar outer edge seat located in spaced parallel relation to the diaphragm. The diaphragm moves to create a pressure in the input/output chamber which balances the input signal force on the diaphragm. An output port is connected to the input/output chamber and to the load in the illustrated embodiment to transmit the pressure and/or flow to the load. The pressure of the input signal and of the stream acts on opposite sides of the diaphragm and positions the diaphragm relative to the orifice seat to create a restricted flow passageway having the necessary pressure drop to create a balanced pressure condition in the output chamber.

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.