Dynamic current-to-pneumatic converter and pneumatic amplifier

A current-to-pneumatic converter used in an electro pneumatic positioner, the converter having a flexure-nozzle arrangement to produce a signal pressure proportional to a given electrical current, the converter comprising:

• a coil adapted to supply a variable electromagnetic effect within the converter proportional to current supplied to the coil;
• a flat strip made of magnetic material located in proximity to a nozzle, a portion of the flat strip integrated into a molded spring support, the flat strip having a thickness, wherein the thickness of the flat strip is locally reduced in an area not integrated into the molded spring support;
• and
• a flow regulator having a flat spring securing a plug in a seat within the regulator, the flow regulator proximate to the flat strip of magnetic material,
• wherein the regulator maintains a near constant fluid flow feeding the nozzle, and wherein the electro-magnetic effect from the coil is operable to act on the flat strip of magnetic material to move the plug to allow a pneumatic pressure proportional to the supply current.

A current-to-pneumatic converter of an electropneumatic positioner, the converter comprising:

• a cantilevered flexure integrally secured to a molded spring support;
• a first bias spring positioned on a first side of the flexure;
• and a second bias spring positioned on a second side of the flexure,
• wherein the flexure, the molded spring support, and the bias springs are centered around a nozzle of the converter, wherein a thickness of the flexure is locally reduced in an area not integrated into the molded spring support.

A method for generating an output flow proportional to a signal pressure, the method comprising:

• receiving an input signal pressure into a rely-type amplifier, the amplifier comprising:
• a balance plug adapted to generate a balancing force proportional to the input signal pressure;
• a supply plug coupled to the balance plug by a bead chain, the supply plug adapted to allow a portion of the input signal pressure to enter the amplifier;
• and
• a vent plug proximate to the supply plug, the vent plug adapted to vent high output pressures;
• generating an output pressure proportional to the input signal pressure.