Pressure sensor for installation in a wall element subjected to pressure of a fluid medium, such as a hydraulic pressure line, e.g. in diesel fuel injection systems

Abstract

To provide an unyielding support surface for a film-type, typically thick-film resistor (10) made of pressure-responsive resistance material, an unyielding pressure-tight mass of insulating material, for example a melt of glass, ceramic, or suitable plastic, is introduced into a wall portion of a wall element (11) in which a fluid pressure medium, such as high-pressure fluid for injection to a Diesel engine, is retained. The insulating mass is, preferably, formed as a plug element, for example retained within a metal screw which, simultaneously, can form a venting screw for the fuel injection system. One or two electrical conductors (12, 13) pass through the plug element, which if a metal screw, surrounds the insulating mass, the resistance element can extend over the edge of the metal which, then, can form a ground or return connection. The surface of the plug element is either flush with the surface of the wall or, for example, forms a laterally relieved slot extending parallel to the axis of the plug, which slot may be filled with a protective pressure-transmitting compound and covering the electrical resistance element there located, so that the end surface of the screw and pressure-transmitting filler will be flush with the wall (11) confining the pressure medium.

Dependencies are inferred from the claim text.