Proportion Air manufactures electronic air pressure regulators and air flow control valves in a variety of configurations. High flow control valves are closed loop electronic pressure regulators that can achieve forward flow rates up to 200 SCFM and exhaust flow rates up to 300 SCFM. Electronic pressure control valves feature control limits up to 1000 PSI, while ultra high resolution pressure control valves are capable of resolutions as high as +/- 0.005% F.S.

Madden Manufacturing supplies Griffco diaphragm back pressure valves for chemical feed system applications. The valves can handle pressures ranging from 10 to 350 PSI.