Safety device for clamping screws on pressurized fluid receptacles

A safety device for the clamping screws of pressurized fluid receptacles comprising an internally faceted socket recess in the head of the clamping screw and a threaded axial bore in its shaft. Into the latter is screwed a bleed screw the head of which occupies the socket of the clamping screw. The need to unscrew the bleed screw to gain access to the socket of the clamping screw prevents the inadvertent unscrewing of the clamping screw under pressure by alerting the operator to the presence of pressure, as the bleed screw opens a bleed channel and thereby creates a small fluid leak. The bleed channel extends alongside the threaded axial bore in the clamping screw and is normally closed by the head of the bleed screw.