Patent GB-714900-A (GB)
Title: Improvements in or relating to apparatus for the volume reduction of gases flowing in pipe-lines
IPC: F16L55/00
Filed: 1952-10-10
Abstract: 714,900. Integrating-apparatus ; pressure gauges. GEHRE, H Oct. 10, 1952 [Nov. 24, 1951], No. 25492/52. Classes 106 (2) and 106 (4) Integrating mechanism in a meter for measuring the volume of a gas flow reduced to standard conditions by subjecting a comparison-gas to the service conditions of the gas being measured so that the volume change of the comparison-gas controls a variable intermediate drive in the counting mechanism drive of the gas meter comprises a ring-balance in which the comparison-gas is enclosed by a sealing liquid on the other side of which the service pressure of the gas being measured is exerted to produce a displacement. of the ring-balance for controlling the intermediate drive. In one embodiment of the invention, Fig. 1, the gas to be measured passes through a closed chamber 6 in which a ring- balance 2 is pivoted in a knife-edge bearing 1 and fills a part of the ring from the opening 5 to the meniscus A of mercury filling the lower, part which seals the comparison-gas, initially introduced through a tap 4, between the meniscus Al and the closed end 3 of the ring. Changes in service pressure of the gas will cause changes in volume of the comparison-gas, movement of the mercury and rotation of the ring until equilibrium is established when the angular displacement of the ring will be a function of the volume of the comparison-gas and may be used to control a variable transmission in a drive to a counter 23. As shown, Fig. 1, the variable transmission comprises a block 7, counterpoised by a weight 8, with a profile. 7<SP>1</SP> determined empirically or by . calculation so that a tip 10 of a pivoted arm 12 oscillates between the profile 7<SP>1</SP> and a fixed stop 9 with an amplitude proportional to the required reduction factor and with a frequency determined by the gas flow, the flow determining the speed of rotation of the shaft 13 which oscillates the arm 12 through crank means 14, 15, 16 and spring 17. The arm 12 thus drives the counter through link 18 and pawl and ratchet 19, 20 at a speed proportional to the volume gas flow modified by the required reduction factor. In order that the device may be transported safely the ring may be lifted from the knife edge bearing 1 and clamped against two stops 25 by means of a screw 24 and taps 26, 26<SP>1</SP>, 26<SP>11</SP> prevent undue movement or escape of the mercury. In a modification, Fig. 2, one limb of the ring-balance is formed as a spherical drum 27 linked by a rigid duct 28 and by screwing a cap-nut 34 with valve plate 35 onto a rod 29 prevented from rotation and carrying valve plate 31 the valve plates 35, 31 may be brought into contact with seatings at the opening 5 and at the bottom 32 of duct 28 to seal off the different sections when the apparatus is not in use. Weights. 8, 8<SP>1</SP> bring the ring- balance into unstable equilibrium but stable equilibrium may be achieved by providing a loading-weight 36, Fig. 1, and the errors thus introduced being proportional to the angular displacement may be compensated by modifying the profile 7'. Errors due to volume change of the mercury due to temperature changes may be eliminated by forming part of the ring-balance wall as a movab'e member 39, Fig. 3, and arranging for it to be moved appropriately with temperature changes through levers by a temperature sensitive device 37 preferably arranged in a plane perpendicular to that of the ring-balance. Normally results are required accurate within certain limits and it is possible to form a profile 7' as a flatter curve than would be necessary for absolute accuracy having regard to the desired limits, a flatter curve being mechanically desirable.