Valve position controller

A valve position controller for controlling the position of an industrial valve element of an industrial valve apparatus to thereby achieve a desired flow of conduit fluid through a conduit as measured by a fluid-condition transducer and monitored by a process controller, said industrial valve apparatus being of a type comprising a fluid-actuated motivator attached to said industrial valve element for moving said industrial valve element and a position-sensing transducer for producing an analog electrical signal corresponding to an actual position of the industrial valve element, said valve position controller comprising:

• closing and opening actuating valves for respectively receiving pressurized actuating fluid from a pressure source and controlling flow of said actuating fluid to and from said motivator to thereby move said industrial valve element;
• an electrical-signal comparator for use in an automatic mode for receiving and comparing an electrical actual-position signal from said position-sensing transducer with an electrical desired-position signal from said process controller and producing control signals in response to a difference between said actual-position and desired-position signals;
• closing and opening solenoids respectively coupled to said closing and opening actuating valves for receiving said control signals and respectively moving said closing and opening valves to positions for allowing flow of pressurized actuating fluid to and from said motivator for opening and closing said industrial valve element;
• wherein is further included a mode switch for switching the valve position controller from said automatic mode into a manual mode in which said control signals from said comparator are deactivated and manually operated close and open switches are energized so that said closing and opening solenoids can be manually energized for closing and opening the industrial valve element by said close and open switches;
• and
• wherein is further included closing and opening locking valves respectively positioned between each of said closing and opening actuating valves and said motivator for closing to block actuating fluid flow to and from said motivator when said mode switch is in said manual-mode position and neither of said manually-operated close and open switches is activated but for opening to allow actuating fluid flow to and from said motivator when said mode switch is in said manual-mode position and either of said manually-operated closed and open switches is activated.

A valve position controller for controlling the position of an industrial valve element of an industrial valve apparatus to thereby achieve a desired flow of conduit fluid through a conduit as measured by a fluid-condition transducer and monitored by a process controller, said industrial valve apparatus being of a type comprising a fluid-actuated motivator attached to said industrial valve element for moving said industrial valve element and a position-sensing transducer for producing an analog electrical signal corresponding to an actual position of the industrial valve element, said valve position controller comprising:

• closing and opening actuating valves for respectively receiving pressurized actuating fluid from a pressure source through respective closing and opening input lines and exhausting it through respective closing and opening exhaust lines to thereby control flow of said actuating fluid to and from said motivator and thereby move said industrial valve element;
• an electrical-signal comparator for use in an automatic mode for receiving and comparing an electrical actual-position signal from said position-sensing transducer with an electrical desired-position signal from said process controller and producing control signals in response to a difference between said actual-position and desired-position signals;
• closing and opening solenoids respectively coupled to said closing and opening actuating valves for receiving said control signals and respectively moving said closing and opening valves to positions for allowing flow of pressurized actuating fluid to and from said motivator for opening and closing said industrial valve element;
• wherein is further included a mode switch for switching the valve position controller from said automatic mode into a manual mode in which said control signals from said comparator are deactivated and manually operated close and open switches are energized so that said closing and opening solenoids can be manually energized for closing and opening the industrial valve element by said close and open switches;
• wherein is further included closing and opening locking valves respectively positioned between each of said closing and opening actuating valves and said motivator when said mode switch is in the manual-mode position and neither of said manually-operated close and open switches is activated to thereby lock the motivator in place;
• wherein said closing and opening actuating valves are biased to move to a home position upon loss of power;
• wherein said respective closing and opening input and exhaust lines of at least one of the closing and opening actuating valves can be interchanged so that upon a loss of power the fail safe position of the motivator depends upon the configuration of the input and exhaust lines of the at least one of the closing and opening actuating valves;
• and,
• wherein is further included an electrical switch for reversing operation of the solenoid of the at least one of the closing and opening actuating valves upon operation of the electrical switch so that the at least one of the closing and opening actuating valves will function properly to close and open the industrial valve element upon respective operation of the manually operated closing and opening switches in the manual mode and in response to the control signals of the comparator in the automatic mode when said input and exhaust lines of said at least one of the closing and opening actuating valves are interchanged.