基本信息
摘要：892,493. Measuring electrically. DUNKEL, M. M., [trading as LEYBOLD'S NACHFOLGER, E.]. Feb. 23, 1959 [Feb. 22, 1958], No. 6158/59. Class 40 (1). In a heat conduction manometer comprising one or more temperature-sensitive measuring elements, e.g. resistors or thermocouples, and one or more apertured or bifurcated oscillating members operable to induce a flow of the gas whose pressure is to be measured around or past the measuring elemen(s), the temperature of the measuring element(s) is maintained constant and the heating power necessary to achieve this is measured. In Fig. 1, a leafspring 5 of ferromagnetic material is oscillated by an iron-cored solenoid 2 supplied with voltage- and frequency-stabilized A.C. to create a flow of the test medium around a semi-conductor bead 6 located within an aperture 51 in the leaf-spring; alternatively, the spring may be bifurcated about the bead. The bead is connected to a measuring device 14 comprising a bridge circuit the output of which controls the heating current to the bead and actuates a meter 15 to give an indication of the test pressure. In a modification, two oscillating leaf-springs and two semi-conductor beads are used. The leaf-spring(s) may be oscillated by electrostatic, piezo-electric or mechanical drive, and the measuring element(s) may be fixed to the spring(s) for oscillation therewith. The amplitude and/or frequency of oscillation of the spring(s) may be kept constant or varied, for example, in dependence on the current being measured; electrical or mechanical compensation may be provided to off-set the effect of unwanted variations of oscillation amplitude. The manometer may also contain an ordinary heat conduction measuring element.
摘要附图：
