Control system

Control system (10) for a purge valve (12) actuatable by low pressure, intended for a low-pressure or vacuum waste water system, comprising:

• a housing with an external wall,
• a first valve arranged in the housing and switchable from a first position to a second position by dynamic pressure caused by accumulated waste water,
• a first chamber (72) bordered by a first membrane (74), and pressure adjustable via the first valve, and functionally connected with a second valve (34), via which, depending on position, low pressure or atmospheric pressure, to reaches the purge valve,
• a first connection (46), via which the first chamber is connectable with a low pressure source, which in the absence of or at too low dynamic pressure is cut off from the first valve in the first position, and which, at sufficient dynamic pressure, is released by the first valve in the second position,
• a second connection (90, 94, 96, 98) leading to atmospheric pressure and connected with the first chamber, the second connection preferably being adjustable in cross-section,
• with the first chamber being subjected to sufficient low pressure, the first membrane together with the second valve being switchable from a first position connecting the purge valve to atmospheric pressure to a second position connecting the purge valve to a low pressure, and with the first valve in the second position, the first connection being released between the source of the low pressure and the first chamber, cutting off the second connection that leads to the first chamber and is capable of being subjected to atmospheric pressure,
• wherein the first valve (32) comprises a release membrane (36), via which the first connection (46) is lockable when the first valve is in the first position, and a second membrane (38), connected by a spacer element (40) with the release membrane, and cutting off the second connection (90, 94, 96, 98) when the first valve is in the second position,
• with an intermediate space (52) between the release membrane and the second membrane being capable of being subjected to dynamic pressure.