GB689581A - Improvements in positive displacement liquid meters - Google Patents

Abstract

689,581. Liquid meters. LE CLAIR, C. C. S., and TECALEMIT, Ltd. Feb. 21, 1951 [March 2, 1950], No. 5368/50. Class 69 (ii). In a positive displacement liquid meter comprising at least two double-acting pistons 37, 37a, which are reciprocable in cylinders 12, 13 under the pressure of the liquid flowing through the meter, and mechanism which interconnects the pistons in such a manner that they are not only caused to reciprocate but also to rotate continuously in the same direction, the reciprocating motion of the pistons is communicated continuously to the counter mechanism, means being provided for controlling the flow of the liquid from the inlet side of the meter through the cylinders to the outlet side of the meter. The cylinders are seated in abutments 4, 5, 6, 7, and 8, 9, 10, 11 forming isolated passages 14 and 15. Liquid flows from the inlet 2 into the passage 14, and from the passage 15 to the outlet 3. The cylinders have inlet ports 16, 17 and outlet ports 18, 19. The pistons are divided into compartments each having a port such as 46, 47, 48, 68, or 69, and an upper or lower sloping wall such as 54, 55, (Fig. 1) or 74, 75, (Fig. 2) so that compartments 42, 44, 63, and 65 are each closed at the top and open at the bottom while compartments. 43, 45, 62, and 64 are closed at the bottom. The piston rods 24, 25 carry toothed wheels 89 and 90, and connecting rods 93 and 94. The wheels 89 and 90 mesh with a deep pinion 88 on a shaft 87 carrying a mitre wheel 86 engaging a mitre wheel 85 fixed on a crankshaft 79, the wheel 85 also driving a mitre wheel 105 connected to the counter mechanism. Each end of the crankshaft has a crank web 81 formed with a conical hole 82 in which the conical head 83 of a crankpin 84 is adjustably fitted, the two crank pins being set at 90‹ apart and connected to the rods 93, 94. By rotating the crank pins, the throw of the cranks and hence the stroke of the pistons 37, 37a is altered. The wheels 85 and 86 have the same number of teeth, and the wheels 89 and 90 each have twice as many teeth as the pinion 88, hence both pistons will revolve in the same direction at half the crankshaft speed, i.e. at each single stroke up or down the piston will turn through 90‹. As shown in Figs. 1 and 2, the piston 37 is at the top of its stroke with the ports 16 and 18 closed by the parts 51 and 52 of the piston ; the piston 37a is at mid-up-stroke with liquid flowing from the inlet chamber 14 into the compartment 63, which is closed at the top, and flowing from the compartment 64, which is closed at the bottom, into the outlet chamber 15, the piston moving upwards and rotating clockwise until the ports 17 and 19 are closed by the parts 71 and 72, by which time the ports 47 and 48 of piston 37 are in register with the ports 16 and 18 and liquid flows into the compartment 43 and out of the compartment 44 so that this piston moves downwards. The combined continuous reciprocating and turning movements of the pistons continue as long as liquid flows through the meter which can be made to deliver the correct quantity by adjusting the setting of the two crankpins 84. An alternative method of calibrating the meter by adapting the bottom end of one or each of the piston rods to function as a compensating pump plunger is described.