Abstract: A flow indicator has a pivoting flap fitted in ducting of a hydraulic installation which transports contaminated liquids. To permit the purge of a reservoir, the flap has an opening for air returning through the ducting. The opening prevents overpressure or vacuum in a circuit. The invention applies specifically to purge and vent circuits for nuclear power installations.

Abstract: The technical field of the invention is that of valves of the guillotine type for powdered, granulated or pasty products.The object is to provide such valves which are self-cleaning and therefore avoid a wedging of the guillotine plate which opposes the sealing effect of the closure of the valve by the plate.The gist of the solution of this problem resides in the fact that there are interposed, between the slideways of the body of the valve and the slidable plate straight elongated section members which are rigid with the slidable plate and are distinctly longer than this plate. These section members fill the whole of the space of the slideways and prevent the product passing through the valve from penetrating and accumulating in the slideways.The main use of the invention resides in the equipment of installations conveying powdered, granulated or particulate products.