Patent ID: 8439066

Claim:
A double seat valve provided with first and second closing members ( 3 , 4 ) arranged in series, which are movable relative to each other and which prevent in the closed position of the double seat valve ( 1 ) overflowing of fluids from a first valve housing part into another valve housing part ( 1 b ; 1 a ), which are limited in the closed but also in the opened position by a leakage cavity ( 5 ) that is connected with the area surrounding the double seat valve ( 1 ), wherein in the closed position of the first closing member ( 3 ) which is constructed as a slide piston, the member is sealingly accommodated in a connection opening ( 2 c ) of interconnecting valve housing parts ( 1 a , 1 b ) and comes to rest during its opening movement on a second closing member creating a seal, which is arranged on a second seat surface ( 2 b ), so that the second closing element is also transferred during further opening movement into a fully opened position (H), wherein the first closing member ( 3 ) is equipped with a seat valve ( 6 ) creating a seal against a cylindrical seat surface ( 2 a ) formed radially relative to a connection opening ( 2 c ), with the closing members ( 3 , 4 ), which can be transferred independently of each other with a respective first partial stroke (T 1 ) and second partial stroke (T 2 ), in each case gap-wide into a seat cleaning position in order to clean their seat surfaces ( 2 a , 2 b ), wherein the second closing member ( 4 ) can be transferred with the second partial stroke (T 2 ) which is equidirectional with the opening movement, along with the first closing member ( 3 ) with the opening movement against the first partial stroke (T 1 ) into the respective seat cleaning position, wherein the double seat valve ( 1 ) is opened upward relative to a vertical arrangement and is equipped with a drive having actuating adjustment rods ( 3 a , 4 a ), jointly actuating both closing members ( 3 , 4 ), wherein an outlet bore ( 3 d ), which is provided in a penetrating pipe shaft ( 3 b / 3 c ) creating a seal in the downward direction with the first valve housing part ( 1 a ) arranged in a valve housing part ( 1 a ) deployed on the first closing member ( 3 ), connects the leakage cavity ( 5 ) with the surroundings, and wherein the seat cleaning position of the first closing member ( 3 ) is at the same time opened and can be cleaned in the sealing position between the pipe shaft ( 3 b / 3 c ) and the first valve housing part ( 1 a ), wherein the first closing member ( 3 ), which is moved downward with the first partial stroke (T 1 ), is provided with a freely penetrable ring gap (S 21 ) which is formed between an outer surface (K) of the pipe shaft ( 3 b / 3 c ) and a first rod seal ( 21 ) arranged in an axial direction in the first valve housing part ( 1 a ).