A subsurface safety valve including safe additive injection

A B S T R A C T A safety valve (8) for an effluent-production installation, the safety valve comprising a longitudinal 5 shell in which there extends a production tube (22) defining an inside volume for effluent flow, the tube being movable in translation inside the shell in an axial direction (A) between an advanced position in which effluent flow is authorized from the bottom of the 10 installation towards the surface, and a retracted position in which effluent flow is prevented, the valve being characterized in that it further includes a connection duct (42, 44, 46, 50, 60, 62, 64) between a feed line for feeding at least one additive from the 15 surface and an injection line for injecting the additive downhole, a safety plug (100) being provided in the connection duct in order to close or open the duct depending on whether the production tube is in its retracted position or its advanced position. F g Fig. 1 -. 30' Fl 8 22 F 3 8-/ 22' 1 1 5 /1 2 11 Fig. 2