GB346183A - - Google Patents

Abstract

346,183. Combined pressure gauge and thermometer. SCHMIDT'SCHE HEISSDAMPF-GES., 2, Rolandstrasse, Wilhelmsh÷he, Cassel, Germany. April 25, 1930, No. 12762. Convention date, May 21, 1929. [Class 106 (ii).] In a combined pressure and temperature indicator for the heating media of heat transferrers the movements of the indicators according to the non- linear law connecting the temperature and pressure of the heating medium in the saturated condition are brought into relation in such a way that if the heating medium becomes superheated, a departure from such related movement occurs. An electric thermometer 4 of the rotating drum type is connected by a pipe 3 to an extension 2 immersed in the steam flowing through the tube 1 of a heat transferrer. The pointer 8 of the thermometer is rotated by the thermometer drum and moves over a scale indicating e.g. 270‹ C. to 370‹ C. For measuring pressure a Bourdon tube 10 is connected to the medium by a pipe 9 the movement of the free end being transmitted to a spindle 13 by quadrant and pinion in the usual way. A cam disc 18 designed according to the non-linear law connecting temperature and pressure of the saturated medium is fixed to the spindle 13, and has secured to it one end of a band 19 which passes over and is fastened to a disc 20 journalled coaxially with the thermometer spindle and carrying a pointer 21. A disc 24 fixed with the disc 20 has attached to it a band 25 connected to the casing by a spring 26. The transmission between the pressure gauge and thermometer spindle may be through cams coacting with a roller or through levers. The two pointers move in unison as long as the steam in the tube 1 is saturated. If the steam becomes superheated the pointers diverge and as the thermometer pointer 8 is preferably coloured red this is readily noticeable. A lug on the temperature pointer may be arranged to engage the pressure pointer on a predetermined divergence and operate an electric signal circuit. In a second form the pressure gauge and thermometer have a common axis, the spindle of the temperature pointer being hollow to receive the spindle of the pressure pointer. Instead of the movement of the manometer pointer being brought into agreement with the temperature pointer, the reverse may be the case. In a third form the spindles 48, 50, Fig. 5, of the pressure and temperature pointers are arranged eccentrically. The pointers 49, 51 intersect continuously on the arc 52 so long as the steam is saturated. The temperature pointer 51 is cut away so that the right-hand edge is displaced from its centre line and so with normal movements does not come into contact with a pin 54 arranged in the centre line at the end of the pressure pointer. Contact occurs when the temperature pointer moves forward relatively to the other upon superheating taking place. By connecting the pointers in an electric circuit 55 with a bell 56, contact between the pointers may be made to operate a signal.