Abstract: A digital valve positioner for use with an actuator. The digital valve positioner includes a housing, at least one exhaust port opening formed in the housing, and a vent assembly operatively coupled to the at least one exhaust port opening. The vent assembly includes a body having a bore, a valve seat surrounding the bore, and a check valve disposed within the bore. The check valve is arranged to shift from a closed position seated against the valve seat to an open position disposed away from the valve seat. A plurality of barriers is disposed around and positioned to enclose the check valve. The plurality of barriers is arranged to prevent an external medium from entering the check valve and to provide a tortuous flow path for the exhaust medium reducing sound through the vent assembly.

Abstract: A digital valve positioner for use with an actuator. The digital valve positioner includes a housing, at least one exhaust port opening formed in the housing, and a vent assembly operatively coupled to the at least one exhaust port opening. The vent assembly includes a body having a bore, a valve seat surrounding the bore, and a check valve disposed within the bore. The check valve is arranged to shift from a closed position seated against the valve seat to an open position disposed away from the valve seat. A plurality of barriers is disposed around and positioned to enclose the check valve. The plurality of barriers is arranged to prevent an external medium from entering the check valve and to provide a tortuous flow path for the exhaust medium reducing sound through the vent assembly.

Abstract: A digital valve positioner for use with an actuator. The digital valve positioner includes a housing, at least one exhaust port opening formed in the housing, and a vent assembly operatively coupled to the at least one exhaust port opening. The vent assembly includes a body having a bore, a valve seat surrounding the bore, and a check valve disposed within the bore. The check valve is arranged to shift from a closed position seated against the valve seat to an open position disposed away from the valve seat. A plurality of barriers is disposed around and positioned to enclose the check valve. The plurality of barriers is arranged to prevent an external medium from entering the check valve and to provide a tortuous flow path for the exhaust medium reducing sound through the vent assembly.

Abstract: A digital valve positioner for use with an actuator. The digital valve positioner includes a housing, at least one exhaust port opening formed in the housing, and a vent assembly operatively coupled to the at least one exhaust port opening. The vent assembly includes a body having a bore, a valve seat surrounding the bore, and a check valve disposed within the bore. The check valve is arranged to shift from a closed position seated against the valve seat to an open position disposed away from the valve seat. A plurality of barriers is disposed around and positioned to enclose the check valve. The plurality of barriers is arranged to prevent an external medium from entering the check valve and to provide a tortuous flow path for the exhaust medium reducing sound through the vent assembly.

Abstract: A non-contacting position sensor having primary and secondary sensors detects relative displacement between two objects. The secondary sensor may function as a limit switch detection element in a limit switch circuit, and is positioned to be in the path of magnetic flux not detected by the primary sensor. The primary sensor is positioned in a flux path between sections of a flux gathering pole. A secondary sensor is positioned in a leakage flux path outside the first sensor or may be positioned in a secondary flux path.

Abstract: A non-contacting position sensor having primary and secondary sensors detects relative displacement between two objects. The secondary sensor may function as a limit switch detection element in a limit switch circuit, and is positioned to be in the path of magnetic flux not detected by the primary sensor. The primary sensor is positioned in a flux path between sections of a flux gathering pole. A secondary sensor is positioned in a leakage flux path outside the first sensor or may be positioned in a secondary flux path.

Abstract: A method and apparatus for controlling a valve/actuator plant by generating a plurality of independent correcting control signals each responsive to a plurality of respective input signals and at least one of these input signals being the set point signal. The plurality of independent correcting control signals includes a pneumatic flow signal. The correcting control signals may be derived from all linear control signals, all non-linear control signals, or a combination of linear control signals and non-linear control signals.

Abstract: A high pressure, fluid level sensor and seal includes a body supporting a removable end cap and housing a trunnion bearing comprising a pivot disk that is pivotable about a pivot axis formed by a pair of pivot pins that are secured to the base of the end cap. The pivot disk is connected to a control arm that freely passes through the end cap. The pivot disk is also connected to a displacer arm that engages a float or displacer in communication with fluid in a high pressure tank. A compression spring acting between the control arm and the end cap biases the pivot disk against the pivot pins. The control arm engages an operating mechanism in a controller that includes a relay. The body is secured in the wall of a high pressure tank. A high pressure seal is formed by a spacer that forms a slip fit with an annular recess on the pivot disk and which engages the end cap and O-rings. The O-rings couple the spacer to the pivot disk and couple the spacer to the end cap.

Abstract: A four-mode pneumatic relay includes a relay body defining four chambers, each coupled to a port. Two of the chambers are formed by a diaphragm assembly consisting of a rolling diaphragm coupled to an input post that drives a movable orifice shaft and a pair of diaphragms of different effective areas coupled to said movable orifice shaft. A movable plug assembly includes valve plugs for interconnecting the first chamber with the second chamber and the second chamber with the third chamber via a valve seat and an orifice and recess in the movable orifice shaft. A pair of mechanical switches couple different ones of said ports for providing multi-mode operation. One switch supplies input pressure to either the first port or the third port and another switch couples the second and fourth ports together to vents the fourth port.