| 摘要 |
<p>1513285 Measuring pressure GEOPHYSICAL RESEARCH CORP 1 Aug 1975 [21 April 1975] 32271/75 Heading G1N A gauge for remotely measuring pressure, as in a bore hole, comprises a housing 10, 12 having a portion thereof forming an integral electrically conductive diaphragm 16, the outer surface 16A of which, in use, is exposed to the pressure to be measured and a stator element 22 of insulating material positioned within the housing 10, 12 adjacent and spaced from the diaphragm 16 and having an electrically conductive surface 34, 36 thereon forming a capacitive relationship with the diaphragm. Circuit means are also provided for forming from an input signal to the circuit, an A.C. signal responsive to the spacing between the diaphragm and stator element, the A.C. signal being, in use, fed into a cable for transmission to a stator remote from the housing. As shown the stator element is provided with two concentric conductive surfaces, the outer one 36 of which with a portion of the diaphragm which is substantially unflexed during pressure measurements forms a reference capacity. However a single conductive surface only may be provided, Fig. 3, (not shown). A support 42 carries a toroidal core conductor 44, a switching device 46 and an oscillator transistor 50 all of the circuit means. The switching device 46 switches between the reference capacitor 16, 36 and the measuring capacitors 16, 34. A reference oscillator may be provided, Fig. 5, (not shown). A temperature sensor 73 by which errors caused by temperature variation may be eliminated is provided in the housing. The space above the diaphragm 16 is evacuated.</p> |
