GB425286A - Improvements in or relating to pressure gauges - Google Patents

Abstract

425,286. Pressure gauges. DENT, D. F., 4, Brick Court, Temple, London. Aug. 25, 1933, No. 23665. [Class 106 (ii)] Relates to U-tube manometers of the type in which two vessels contain immiscible liquids, the meniscus separating which moves along the narrow base leg over an indicating scale, and consists in disposing the vessels coaxially or substantially coaxially one within the other so as to be unaffected by the considerable inclinations of the gauge experienced when mounted in aircraft. The vessels 10, 11 of cylindrical form are connected by a U-tube 12 having a much smaller section than either vessel. The vessel 10 is filled with a saturated solution of water in phenol and the vessel 11 with a saturated solution of phenol in water. The outlets 14, 15 serve to communicate with the sources of pressure. The apparatus is particularly suitable for use on gliders and in this case the inner vessel 10 is connected to a thermos flask 16 by a conduit 17 embodying a leak to the atmosphere connected to the outlet 14 and the vessel 11 is connected directly. For indicating air speed, the outlet 14 is connected to a Pitot pressure head and the vessel 11 to a static head. For use as a sensitive pressure gauge the leak is dispensed with and a tap placed in the outlet 14 which can be opened and shut to set the gauge. To avoid movement of the meniscus into either vessel through a sudden dive or ascent, the limb A ... B is provided at the top and bottom respectively with bulbs 18, 19 of sufficient capacity to take all the liquid in the chambers 11 and 10. In a modified form the chambers are made of spherical form and concentric, this form giving a wide scale in the middle of the range.