Precision valve control

A valve control for a hermetically sealed valve system, wherein said valve system operates with a solenoid driven magnetic actuator controlled by electronic input signals;

• with the solenoid causing the selective formation of a magnetic force field of predetermined varying strength, to cause controlled movement of a link element, linked to a valve, for the controlled opening and closing of the valve, the improvement comprising said electronic input signals being within a predetermined range having upper and lower limit values, and wherein individual values of said electronic input signals, within said predetermined range, are calibrated to specific valve positions between said opening and closing of the valve, with one of said upper and lower limit values being calibrated to a closed valve position and the other of said upper and lower limit values being calibrated to a fully opened valve position;
• said valve system further including comparator means, actual valve position monitoring means, and deviation control means;
• wherein the comparator means continuously compares the electronic input control signals, calibrated to a predetermined specific valve position, and electronic feedback signals from the actual valve position monitoring means;
• said electronic feedback signals being calibrated to predetermined valve positions;
• whereby actual position deviation of the valve, from a desired input position, generates an error signal from the deviation control means, with said error signal causing said solenoid to change the strength of the magnetic force field, with concomitant change in valve position, until said error signal is substantially eliminated, wherein the actual valve position monitoring means comprises a linear variable differential transformer (LVDT) adapted to monitor movement of the link element, with actual position of the valve being monitored thereby, and wherein the LVDT creates voltages, each being predeterminately related to a different valve position, as the electronic feedback signals.