GB717060A - Improvements relating to flow meters - Google Patents

Abstract

717,060. Indicating-apparatus; pressure gauges. LANDIS & GYR AKT.-GES. April 3, 1952 [April 6, 1951], No. 8559/52. Classes 106 (2) and 106 (4). [Also in Groups XXIX and XXXVIII] In a flow meter, the ratio between the two effective arms of a lever, arranged in the transmission from a root extraction cam to an indicator member, is varied in accordance with the condition of the medium passing through the meter, by means producing substantially no retarding effect on normal movement of an instrument for measuring the condition. As shown in Fig; 1, the transmission mechanism of : a flow meter comprises a root-extraction cam 9 acting on a rod 10 connected to pointer 11 through linkwork including a lever 8 controlled by a pivoted arm 36, the transmission ratio of the lever being varied by moving a fulcrum rod 30, engaging, an arcuate,slot 38, about a shaft 28. The.rod 30 is normally at the centre of the lever, and is arranged to follow the movements of a shaft 6 which is responsive to deviations from normal in one or more conditions of the medium where flow is being measured, and, as shown, carries a pointer 7 which is moved by an adjustable linkwork 3, 4, 5 so as to indicate the difference α-# between ,the deviations from normal in temperature and pressure measured by instruments having pointers 1 and 2. The shaft 6 also carries a sector 17 and pin 16 which are periodically clamped by toggle mechanism 19, controlled by a cam 21 on a constantly driven shaft 31, while a further cam 27 allows scissor members 24, 25 to close and cause the rod 30 to move to a position corresponding to that of the pin; an elastic coupling 34 permits free movement of the pointer 7 during the clamping periods. In a modification, the pin 16 carries a member with a curved surface which co-acts with teeth on the members 24, 25; Fig. 4 shows another arrangement in which the rod 30 operates a straight line linkwork carrying a rod 45 which engages a straight slot in the lever 8 and is engaged by a flexible band 47 (replacing the arm 36, Fig. 1) held taut by a spring 49. In further modifications, the shaft 6 is connected to the rod 30 through an electric follow-up device (see Group XXXVII) or a pneumatic transmission (see Group XXIX). As shown in Fig. 9, temperature and pressure measuring instruments 65, 66 control separate plates 67, 68 adjacent outlet nozzles of pipes 71, 72 respectively. The pressures in these pipes act on diaphragms 74, 75 interconnected by a rod 76, so that this rod and rods 77, 30 are moved in accordance 'with the difference between the two pressures which corres-; ponds to α-# above.