Patent ID: 8430110

Claim:
A double-seat valve ( 1 ) having a seat-cleaning function with first and second closing elements ( 3 , 4 ) arranged in series, said first and second closing elements ( 3 , 4 ) are movable relative to each other and, in the closed position of the double-seat valve ( 1 ), prevent overflowing of fluids from a first valve housing part ( 2 a ; 2 b ) into a second valve housing part ( 2 b ; 2 a ) and in the closed as well as in the open position define a leakage cavity ( 16 ), which has a drain outlet leading downward, relative to a vertical arrangement of the double-seat valve ( 1 ), out of the second valve housing part ( 2 b ), having the first closing element ( 3 ) that is a slide piston and is driven independently and in its closed position rests, forming a seal, in a connecting opening ( 2 c ) joining the valve housing parts ( 2 a , 2 b ) together, and during its downward directed opening movement into the completely open position (H), comes into contact in a sealing manner with the second closing element ( 4 ) assigned to a second seat ( 2 e ), and carries this also into the open position (H), having a first seat seal ( 10 ) arranged in the first sealing element ( 3 ) that seals radially against a cylindrical first seat ( 2 d ) formed in the connecting opening ( 2 c ), having the closing elements ( 3 , 4 ) that can be moved independently of each other gap-wide by a partial lift (T 1 , T 2 ), in each case, into a seat cleaning position for the purpose of flushing their seats ( 2 d , 2 e ), wherein the second closing element ( 4 ) can be moved by a second partial lift (T 2 ) in the same direction as the opening movement, and the first closing element ( 3 ) can be moved by a first partial lift (T 1 ) in the direction counter to the opening movement, into its respective seat cleaning position, having valve rods ( 3 a , 4 a ), arranged concentrically inside each other, for the closing elements ( 3 , 4 ) that are led upward into a common drive ( 7 ), having a tubular shaft ( 4 b ), arranged at the second closing element ( 4 ), that penetrates the second valve housing part ( 2 b ) radially outside downward in a sealing manner, and connects the leakage cavity ( 16 ) radially inside via a drain bore ( 4 c ) with an area surrounding the double-seat valve ( 1 ), and that merges upward into the valve rod ( 4 a ) of the second closing element ( 4 ), wherein with the moved first closing element ( 3 ) with the first partial lift (T 1 ) into the associated seat cleaning position, forming a first annular gap (S 1 ), a sealing location ( 3 a , 11 ; 3 a , 11 *; 3 b , 11 ; 3 b , 11 *) is opened upward at a first passage (A) between the first valve rod ( 3 a ; 3 b ) moving the first closing element ( 3 ) and the associated first valve housing part ( 2 a ) in the form of a second annular gap (S 2 ), and said gap connects the interior of the first valve housing part ( 2 a ) to a flush chamber ( 5 b ) of a first flush device ( 5 . 1 ; 5 . 1 *), which encloses the first valve rod ( 3 a , 3 b ).