DOUBLE-SEAT VALVE HAVING A SEAT-CLEANING FUNCTION, AND METHOD FOR CLEANING SAID DOUBLE-SEAT VALVE HAVING A SEAT-CLEANING FUNCTION

摘要

The invention relates to a double-seat valve having a seat-cleaning function (1), wherein said double-seat valve opens downwards and both closing members (3, 4) can be moved independently from one another into a seat-cleaning position by a partial lift (T1, T2) to form a gap in order to rinse the respective seat surfaces (2d, 2e) such that the dependently driven second closing member (4) is brought into the respective seat-cleaning position by means of a second partial lift (T2) in the same direction as the opening movement while the first closing member (3) is brought into the respective seat-cleaning position by means of a first partial lift (T1) in the direction opposite the opening movement. The aim of the present invention is to provide a double-seat valve having a seat-cleaning function of the type described above, which ensures sufficient cleaning of the passage of the valve rod or the extension thereof in form of a pressure compensation piston of the independently driven closing member and to provide a method for cleaning said double-seat valve having a seat-cleaning function. In order to achieve said aim, the double-seat valve (1) opens downwards in relation to a vertical arrangement and, when the first closing member (3) is moved upwards with the first partial lift (T1) into the associated seat-cleaning position forming a first annular gap (S1), a sealing area (3a, 11; 3a, 11*; 3b, 11; 3b, 11*) is open at a first passage (A) between the first valve rod (3a; 3b) moving the first closing member (3) and the associated first valve housing part (2a) in the form of a second annular gap (S2) which connects the interior space of the first valve housing part (2a) to a rinsing chamber (5b) of a first rinsing device %.1; 5.1*) that encloses the first valve rod (3a, 3b).