| 摘要 |
<p>A device for indicating a pressure difference comprises a piston adapted to be adjusted between a first and a second position against the action of a resilent force, when the pressure difference reaches a predetermined value. The piston (14) is movable in a conical cylinder (12) and provided with a piston-rod (14a) extending through an opening at the narrow end of the cylinder and having an area actuated by the pressure difference, said area being dimensioned to start the adjustment when said value is reached.</p> |
