METHOD AND DEVICE FOR MACHINING A SEALING SEAT OF A SHUT-OFF FITTING

The invention relates to a method for machining a sealing seat (24a, b), arranged at the end (26) of a connection pipe (8a, b), of a shut-off valve (6) fitted in a power generating or industrial plant (2), which method comprises the following steps: a) an upper valve part (16) and the internal housing fittings (32) are removed from the housing (10) of the shut-off valve (6), whereby a housing opening (14) is exposed, b) a clamping device (40), having a counter-bearing (56), is introduced through the housing opening (14) into the or a further connection pipe (8a, b) and fastened to the inner wall (50) thereof, c) a machine tool (58), having a bearing (64), is introduced into the housing (10) through the housing opening (14) and mounted with its bearing (64) on the counter-bearing (56), d) a machining step (B1-4) is carried out with the machine tool (58) on the sealing seat (24a, b), e) the machine tool (58) is detached from the counter-bearing (56) and removed through the housing opening (14), f) if need be, steps c) to e) are repeated with another or the same machine tool (58), g) the clamping device (40) is detached from the connection pipe (8a, b) and removed through the housing opening (14), and h) the upper valve part (16) and the internal fittings (32) are attached to the housing (10). A device for machining a sealing seat (24a, b), arranged at the end (26) of a connection pipe (8a, b), of a shut-off valve (6) fitted in a power-generating or industrial plant (2) comprises a clamping device (40), which can be introduced through a housing opening (14) of the shut-off valve (6) into the or a further connection pipe (8a, b) and includes a counter-bearing (56) and a fastening element (47) interacting with the inner wall (50) of the connection pipe (8a, b), and at least one machine tool (58), which can be introduced through the housing opening (14) into the housing, for carrying out a machining step (B1-4) on the sealing seat (24a, b), wherein the machine tool (58) has a bearing (64), which can be mounted in the counter-bearing (56). L'invention concerne un procédé d'usinage d'un siège d'étanchéité (24a, b) d'un robinet d'arrêt (6) monté dans une installation industrielle ou de production d'électricité (2), ledit siège étant placé à l'extrémité (26) d'un tube de raccordement (8a, b). Le procédé comprend les étapes suivantes : a) la partie supérieure (16) du robinet et les éléments intégrés (32) dans le corps sont ôtés du corps (10) du robinet d'arrêt (6), u