Double seat valve with two serially arranged closing members (3, 4) which are movable relative to each other, which, when the double seat valve is in the closed position, prevent overflowing of fluids from one valve housing part (1a; 1b) into another (1b; 1a), which, both in the closed and also in the opened position, define a leakage cavity which is connected to the area surrounding the double seat valve, wherein, in the closed position, the first closing member, designed as a slide piston, is received in a sealing manner in a connection opening which interconnects the valve housing parts (1a, 1b), and, during its opening movement, comes into position in a sealing manner on the second closing member allocated to a second seat surface, and the second closing member is also transferred into a fully opened position as the opening movement continues, wherein the first closing member comprises a first seat seal which forms a seal radially opposite a cylindrical first seat surface formed in the connection opening, with the closing members (3, 4) which can be transferred independently of each other by a partial stroke (T1, T2) in each case across the gap width into a seat cleaning position in order to rinse their seat surfaces (2a, 2b), wherein the second closing member can be transferred by the second partial stroke, which is in the same direction as the opening movement, and the first closing member can be transferred by the first partial stroke, which is in the opposite direction to the opening movement, into the respective seat cleaning position, wherein the double seat valve is opened upwards relative to a vertical arrangement and comprises, at the top, a drive common to both closing members (3, 4) and actuating the adjustment rods (3a, 4a) thereof, wherein an outlet bore which is provided in a pipe shaft (3b/3c) - which is disposed on the first closing member and passes through the first valve housing part downwards in a sealed manner - connects the leakage cavity to the surrounding area, and wherein, when the first closing member is in the seat cleaning position, at the same time the sealing point between the pipe shaft (3b/3c) and the first valve housing part can be opened and rinsed, characterised in that, when the first closing member has been moved downwards by the first partial stroke, an annular gap which can be passed through freely in the axial direction is formed between an exterior surface, which is formed on the outer surface of the pipe shaft (3b/3c), and a first rod seal, which is disposed in the first valve housing part, in that the temporarily formed annular gap is defined radially on the inside by the exterior surface of the pipe shaft (3b/3c), the contour of which surface is provided substantially as a counter-contour to the adjacent contour of the first rod seal when the latter is exposed with respect to the pipe shaft (3b/3c) and is relieved of pressure, in that the first rod seal consists of an elastic sealing part and a rigid insert part, in that a first guide ring is disposed which, on the inside in a guide bore, is passed through by the pipe shaft (3b/3c) and which, with its upper end-face boundary surface, lies against the elastic sealing part of the first rod seal under pretensioning, and in that grooves are provided in the guide bore in order to form through gaps (S22b) which are distributed over the periphery of the guide bore, and the respective longitudinal axis of which is set at a gradient angle (α) with respect to the parallel end-face boundary surfaces of the first guide ring.