Patent ID: 8657598

Claim:
Pressure adjustment device, in particular for stretch blow moulding machines of containers made of plastic material, comprising an opening for dispensing a blowing fluid, said device comprising a hollow body having a first inlet opening for a high pressure fluid and a second inlet opening for a piloting fluid, within said hollow body being slidably arranged a shutter, said shutter being held in closing position by elastic means, wherein the adjustable opening of said shutter occurs, in contrast with said elastic means, by introducing—through said second inlet opening said piloting fluid into a piloting chamber arranged between said hollow body and said shutter, and wherein said piloting fluid has a controlled and adjustable pressure, wherein said hollow body is closed at one end by closing means and at the opposite end by a bell-shaped lid, wherein said closing means are removable and comprise an outer diameter, substantially equivalent to the outer diameter of the hollow body, an intermediate diameter, substantially equivalent to the inner diameter of the hollow body, and an inner diameter such to create an annular groove between it and the inner wall of the hollow body, said annular groove having a sealing means disposed therein, on which said shutter presses when it is in closing position.