GB217470A - Improvements in and relating to flexible diaphragms for use in the measurement of fluid pressures - Google Patents

Abstract

217,470. Hodgson, J. L. Aug. 24, 1923. Elastic-diaphragm pressure gauges.-In gauges of the differential type the diaphragm is protected by stiff centres and by a cradle either on the low pressure side only or on both sides. In Fig. 1 the invention is shown applied to the gauge described in Specification 200,985. The diaphragm, which is provided with stiff centres P<1>, P<2> and conical cradles C<1>, C<2>, is controlled by springs S<1>, S<2>, and the movement is transmitted through the part E, roller R, crank K, and spindle G to an indicating needle. Pressure fluid is admitted through valves X<1>, X<2>, and' air vents V<1>, V<2> are provided, together with an equalizing valve not shown. The tension of the springs can be regulated by the nuts N<1>, N<3>, and the number of free turns in the spring S<2> can be varied by a threaded support W. The diaphragm is made preferably of rubber reinforced with fabric, and is shaped by weaving, stitching, moulding, or otherwise, so, that it can roll without stretching on at least the conical cradle on the low-pressure side. The joint between the diaphragm chamber and the outside air may be formed so as to grip the rim of the diaphragm, as shown in Figs. 2 and 3, so that a tight joint may be made at the rim of the diaphragm without disturbing the central portion. The rim of the diaphragm may be hardened or thickened: In the case of very high pressures a separate joint is made, as shown in Fig. 4, and a separate piece having formed on it the low pressure cradle gripping the rim of the diaphragm between it and the casing flange on the high pressureside.