In the midst of trying to redesign the pneumatic subsystem of a combined system, I'm at the point of validating a new valve would serve as a direct replacement. The reason for the redesign is an inconsistency of operation over many cycles. The delay between the shifting of the solenoid and the pressurization of the Retract side of the Cylinder is inconsistent, causing errors throughout the rest of the system. The goal with the redesign is to return the system to a closer approximation of the original configuration (shorting piping), while using modern valve technology to retain remote control.

Current Pneumatic Circuit:
The system pressure is 90-110 psi, then Filter, Regulated to 60-80 psi, and Lubricated.
Nope, I can't draw

An interest in operator safety moved flow control valves outside of machine guarding at a midpoint in the life of the machine, though there isn't documentation available demonstrating that artificial volume increase in the cylinder. This added roughly 236 inches of 3/4 piping to the system.

For pneumatic reasons, the flow controls have been installed to allow free flow to the cylinder from the source, but metered flow from the cylinder to the exhaust.

The Flow coefficient of the flow control valve is 8.3.
The Proportional Electro-pneumatic valve supports pressure control of the (A) port, aligned to the retract side of the pneumatic cylinder. The maximum effective area of the valve is 52 mm^2, with a flow coefficient of 2.9

Issues investigated beyond the valves: Lubrication is regularly checked throughout operation. The cylinder is new and properly configured Header pressure doesn't vary regulated pressure doesn't vary. The solenoid is in good working order. There isn't an issue with the electronic control circuitry.

  • $\begingroup$ Upon review, I just found the Cv of the proportional valve. Obviously, it isn't 1 for 1 on the Flow control valve. Realizing this, I've looked into the position of the valve, between shut and open). Likely an edit to follow. Elucidating that point. $\endgroup$ – Drunk Cynic Dec 27 '18 at 15:34

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