GB193398A - Apparatus for indicating, measuring or recording physical or chemical quantities or qualities - Google Patents

Abstract

193,398. Roucka, E. Feb. 14, 1922, [Convention date]. Tell-tale apparatus. - In apparatus for recording &c. physical values of the kind in which an auxiliary value co-operates with the value to be measured so that an impulse of energy is produced when the two values have a predetermined ratio, the impulse is produced by the action of a ray of energy on a sensitive device. As shown in Fig. 3, a member 6 carries a source of light 12, and a selenium cell 14 which forms one arm of a wheatstone bridge, a similar compensating cell 36 being included in another arm. The member 6 is continuously rocked by a cam 26, and when it has a definite position relative to a primary indicating pointer 8, light is reflected from a mirror 10 on the pointer on to the cell 14 for an instant. A magnet 44 is thus energized and a momentary impulse sent from a source 50 to the receiving station to energize magnet 92. The latter moves an arm 90 to press a pointer 84, which is continuously moved by a cam 62 in synchronism with the cam 26, on to a record strip. In a modification, Fig. 5, for measuring a small current from the thermoelement 140, a pointer 152 is acted upon by a coil 136, influenced by the value to be measured, and a coil 138 the current through which is being continuously varied. The pointer 152 carries a shutter 150 moving in the path of a beam of heat from a source 146. The arrangement is such that when the two values have a predetermined ratio a slit in the shutter 150 registers with the beam and allows the thermo-battery 148 to be influenced thereby. The element 148 may be arranged in a wheatstone bridge arrangement similarly to the cell 14, Fig. 3. The coils 136, 138 are arranged in a casing having windows 134 of quartz, rocksalt, fluor-spar, &c., transparent, to heat. In examples (1) light normally falls on the sensitive element and is momentarily interrupted by a shutter controlled by the primary value, and (2) the primary element carries a concave mirror which at the desired moment reflects light on to the edge of a prism which refracts the light to illuminate the sensitive element.