GB479282A - Differential manometer - Google Patents

Abstract

479,282. Pressure gauges. COBB, R. B., and SLATER, A. L. July 1, 1936, Nos. 18215/30 and 2475 /37. [Class 106 (ii)] A manometer for indicating (a) rate of ascent or descent of aircraft, or (b) variations in the temperature of a fluid comprises a tapered tube in which a ball is lifted, against the force of gravity, by the flow of fluid therein, the position of the ball giving the desired indications. and being visible through a transparent or translucent portion of the tube. .For use ou aircraft the instrument is provided with 'two tapered tubes a, b containing balls c, d and connected as shown to a heat-insulated chamber h and an air inlet or outlet k fitted with a filter g. The ball d is raised in the tube b as the rate of ascent increases, owing to the How of air from the chamber h to the atmosphere. Similarly the ball c indicates rate of descent, scales being provided alongside the transparent tubes. A photographic record may be obtained by arranging for motordriven films q to pass slits f<1> in a box w behind the transparent, tubes a, b. For indicating temperature variations, a metal container may be secured on the tube k, or may replace the chamber h. In a modification, a vacuum flask n is connected to a block made wholly or in part of transparent material, and having a conduit rumning through it, the portion b, c, d constituting a U-tube in which a single indicator ban a is moved by the flow of fluid. The parts of the tubes c, d above the line o-p are tapered, and the tubes k, l have an elliptical cross-section. The movements of the ball may be recorded on a moving photographic film, the lines traced by the ball being differentiated for the two limbs c. d by exposing columns of different lengths. The tubes, in either of the instruments described, may be cylindrical and formed with tapered slots in the wall.