High accuracy, combined pressure- and temperature sensor used in injection mold for plastic, comprises infra red transmission system and sensor, with piezoelectric axial pressure sensor

摘要

An infra red transparent window (10) is located at one end, in a bore of the casing (15). Infra red radiation arriving, is led through the tube (11) by reflection at its inner surface (12), to an infra red measurement element (13). This is located at the far end of the tube. The pressure measurement section is formed by a piezoelectric quartz component (19). An infra red transparent window (10) is located at one end, in a bore of the casing (15). Infra red radiation arriving, is led through the tube (11) by reflection at its inner surface (12), to an infra red measurement element (13). This is located at the far end of the tube. The pressure measurement section is formed by a piezoelectric quartz component (19). This is positioned around the tube and gripped by the bore wall of the casing (15). It measures axial pressure exerted on the casing. The window is sapphire and tube is internally-polished metal. At least the inner surface is gold. There is a second sapphire window (16) at the far end. The tube acts radially and resiliently against the quartz element (19). The quartz element has an external circular cross section resting against the casing wall. Its internal chordal sections rest against the outside of the tube (11). The casing is highly-insulated from the tube; these two components forming the electrodes of the quartz piezoelectric sensor. The bore accepting the tube, lies centrally and axially within the casing.