Patent ID: 8671968

Claim:
Device for combined fluid replacement and pressure testing in pipes with inaccessible end points, characterised in that the device is a two-piece circulation valve structure comprising: a first valve unit comprising an elastic sealing ring which closes and opens depending on the dynamic fluid pressure through the valve, said elastic sealing ring arranged in a recess to close against a seat in the valve unit in step with an increase in the fluid flow velocity through the valve as a function of the dynamic drop in fluid pressure between said elastic sealing ring and said seat when a fluid flows through a recess and out through one or more fluid conduits in the valve unit, said elastic sealing ring having a shape that ensures that the reduction of pressure as a consequence of the velocity of the fluid leads to the cross-section of said sealing ring being altered to seal against said seat and an O-ring therein; and a second valve unit arranged to permanently close off the fluid flow when the pressure testing is terminated.