Improvements in pressure sensitive devices in which the displacements of a diaphragm are translated into an electrical effect

Abstract

Abstract 549,881. Fluid pressure responsive devices. PHILIPS LAMPS, Ltd. (Naamlooze Vennootschap Philips' Gloeilampenfabrieken). June 6, 1941, No. 7198. [Class 40 (i)] [Also in Group XIX] In a fluid-pressure responsive device for converting pressure variations into a variaable electric quantity by subjecting a diaphragm to the pressure, the diaphragm is mounted in a holder so that the electrical characteristics of the device are not affected by strains set up when the diaphragm is secured in position in the holder or when the holder is mounted on the apparatus to be tested. Temperature compensation is also effected. The device responds by a variation of capacity and is arranged to be screwed into the wall of the cylinder of an I.C. engine. A holder 1 screwed externally at its lower end for insertion in the cylinder is internally screwed at its upper end to receive the member 2 which carries the diaphragm 5 at the end of its lower portion and extends some distance beyond the seal 3 entirely freely in the lower portion of the holder. The diaphragm 5 co-operates with a plate 6 to form a variable capacity, the plate 6 being carried by a thickened part 7 of a rod 8 which is secured by a collar 9 and set screw in a ceramic bush 10 fixed in member 2. The lower end of the holder 1 has a perforated wall 13 and the diaphragm may be protected from hot gases by a mica plate. Cooling is improved by coating the parts 4, 5 with good thermally conductive material, e.g. copper or silver, and temperature compensation is effected by suitable choice of materials for the parts 4 .. 7.

Inventors

No inventors recorded.

Bibliographic Details