A SYSTEM FOR CONTROLLING THE WORKING CONDITIONS FOR MECHANICAL PUMPS, AND A REGULATION VALVE FOR SUCH A SYSTEM

摘要

A system for controlling the working conditions for mechanical pumps supplying associated devices with pressure fluid via a pipe system. A valve means (25) is placed between at least one of the pumps and an appurtenant device supplied by the pump, which valve means is arranged to open only when the pump has started up, and by adjustment of its flow cross-section seeks to maintain its downstream pressure at a value (P3) which is predetermined from the specifications of the pipe system and said device, but gives priority to restrict its flow cross-section so that the counterpressure of the pump does not fall below a given minimum value (P2) determined from the characteristic properties of the pump. The valve means is a regulating valve (25) operating in accordance with this functional principle. The regulating valve is based on a servo function utilising the upstream pressure of the valve, the valve comprisinig a main valve body (34) having an end surface constituting a movable surface in the servo chamber (36), the volume of the servo chamber, and thereby the flow cross-section of the regulating valve, being regulated by a pair of control valves (43, 44) affected by the upstream pressure and the downstream pressure, respectively.