Patent ID: 6014983
Filing Date: 2000-01-18
Classification: F16K,Y10T

Abstract:
A double seat valve with leakage protection, in particular for the food and beverage industry, which in its housing has two cooperating valve plates (6, 7), which define a hollow leakage chamber (10) that typically opens into the open air via lines (11), wherein for actuating both valve plates (6, 7), one common drive is provided, which includes a cylinder (17) with a first work piston (18), loaded on both sides by compression springs (29, 22) and being fixedly connected to the valve shaft (13) of the lower valve plate (7), wherein this valve shaft (13) passes in telescoping fashion through the upper valve plate (6) and its tubular shaft (14), which in turn protrudes with its upper end into the cylinder (17) and there carries an abutment (28) for the lower compression spring (29) that presses the upper valve plate (6) into its seat (8), while the upper compression spring (22), which is braced by its upper end on the upper cylinder cap (23), presses the lower valve plate (7) against its valve seat (9), and a second work piston (36), acting on the tubular shaft, is disposed in the cylinder (17) below the first work piston (18), and a third work piston (30) which is movable on the tubular shaft is disposed between the first and second work pistons, wherein the third work piston (30) is sealingly surrounded on its circumferential surface by the first work piston (18), and the first and third work pistons are embodied as displaceable relative to one another, characterized in that by the first work piston (18) and the third work piston (30) a second work chamber (32) is formed, which is embodied such that it can be subjected to compressed air via a conduit (35), and the first work piston (18) has a first (43) and a second abutment (44), which limits the stroke of the third work piston (30).