Technology Sourcebook
www.foodengineeringmag.com/articles/91757-proportional-pressure-regulator

Proportional pressure regulator
January 10, 2014
Used with air-driven pumps/ejectors, the Piab piSAVE optimize vacuum-controlled proportional pressure regulator senses the vacuum level in the system. The regulator provides maximum feed pressure/vacuum flow to the vacuum pump until the vacuum level starts to build up; it reacts to changes in compressed air pressure or the degree of leakage into the vacuum system to maintain the set vacuum level. It is available as a standalone unit or a click-on version.
Piab;