GB681199A - Improvements in pressure indicating devices - Google Patents

Abstract

681,199. Liquid - level pressure gauges. DYER, J. V., and HOSKYNS, H. W. W. Jan. 11, 1951 [Jan. 11, 1950], No. 719/50. Class 106 (ii). An indicating-device in which small movements of liquid in a tube 18 of relatively wide bore are used to effect larger movements of liquid in a tube 25 of relatively fine bore to indicate pressure is characterized in that the wide bore tube 18 is vertically disposed and open to the gas pressure to be measured, the fine bore tube is connected by liquid-tight connections at one end to the wide bore tube and at the other end to a container 28 open to the ground level atmosphere, and'adjusting means for setting the device to zero are provided, whereby the pressure is indicated against a scale of graduations 29 by the position of the liquid in the fine bore tube 25. In the embodiment shown the scale 29 is graduated to read heights between 35,000 feet and 60,000 feet, corresponding to the pressures measured. When the pressure has fallen to that corresponding to 35,000 feet the height of the tube 18 is adjusted by means of lock-nuts 20 working on a threaded portion 19 until the correct height is indicated, the liquid then moves to the left to indicate height as the pressure is further reduced. A cylindrical enlargement 21 is provided in the tube 18 whose lower end is bent and held in position by a clip 22 brazed to the tube and screwed to a back-board 16. The tube 25 is of transparent glass, 2 mm. in bore, and is secured to the tube 18 bv means of a union 24 screwed on a threaded nipple 23 brazed or otherwise secured to the tube 18 and sealed by a rubber gland 26. In a modification, Fig. 2, the enlargement in tube 18 may be conical, the bend may be replaced by a helical coil and fine adjustment may be obtained by interposing a small cylinder 30 with adjusting screw 31 sealed by a gland 32 with suitable packing 33.