Patent GB-625993-A (GB)
Title: Improvements in or relating to liquid meters
IPC: G01F3/18
Filed: 1947-04-08
Abstract: 625,993. Liquid meters. AVERY-HARDOLL, Ltd., and FRASER, J. April 8, 1947, No. 9344. [Class 69 (ii)] In a liquid meter having pairs of opposed pistons or plungers, each piston or plunger operating in a separate metering chamber, the pistons or plungers being operatively connected to a crankshaft, the rotation of which actuates a valve to connect the chambers alternately to a supply of liquid under pressure and to a delivery connection, and also actuates counting or recording mechanism to indicate the quantity of liquid passing through the meter, the pistons of each pair, there being two pairs, are coaxial one with the other, and the axes of the two pairs of pistons lie in spaced parallel planes and are perpendicular one to the other, each pair of pistons being formed or provided with spaced parallel surfaces adapted to be engaged by a driving member encircling a crank-pin. As shown, a meter comprising a square cross-sectional body 10 is formed with two pairs of circular apertures 11, 11 and 12, 12, one pair 11, 11 being formed co-axially in one pair of opposite walls whilst the other pair 12, 12, one only of which is shown is formed in the other two opposite walls. The axes of the two sets of apertures are displaced one from the other along the length of the body by a distance x which is greater than the radius but less than the diameter of the apertures. A cap 13 covers each aperture and forms a metering chamber. Each cap 13 communicates with a port 16 and by means of a passage 17 communicates with a port 18 in the adjacent end face of the body 10. A crank-shaft 21 is journalled in bearings 24 and 25 and has a spindle 75 at one end. A bush 26 is mounted in each of the apertures 11 and 12, which are surrounded by a ring 27 and a washer 28 bolted to the body 10. Clips 29 are secured by the bolts to locate a spring 31 against the washer 28 and urge it inwardly. Two piston members 32, each comprising a pair of pistons 33 are mounted one in each pair of apertures 11 and 12 so that the pistons 33 project through the apertures. The pistons 33 are cup-shaped and have their open ends outermost and are connected base to base by four connecting bars. Two connecting bars 34 are L-shaped in section whilst the others 35 have arcuate inner surfaces. A diametral rib (not shown), extends across the base of each piston 33, the two ribs having parallel faces. The pistons are positioned so that each pair of ribs lies in a plane perpendicular to the axis of the crankshaft, and a roller 42 mounted around each crankpin 22, 23 lies between the parallel faces of the ribs. The crank-shaft 21 has enlarged portions 43, 44, 45, which engage the bars 34 on the pistons 33 and prevent the pistons from rotating. The caps 13 have a hole 46 threaded and counter bored to receive a stop 47. The counter-bored portion opens into an inner portion 51 which is packed by a washer 52. The stop 47 has a head 53 formed with a series of notches, which is housed in an outer part 54 of the recess. In order to prevent the stop 47 rotating two holes 56 are threaded in the base of the recess'to receive a screw 57 passing through one of the notches. A rotary valve member 61 is urged against a plate 63 secured to the body 10 by a spring 64 acting through a sleeve 65 which bears on the valve 61. The sleeve 65 is prevented from rotating by bolts 69. The ports 18 are connected alternately to an inlet and an outlet both of which are formed in a valve housing 68 bolted to the main body 10. The valve 61 has an inlet port and an outlet port, each having an opening in the face 62 and is connected to the crank-shaft for rotation thereby. Liquid when fed to the inlet by a pump, passes through the ports 18 into the metering chamber which causes a corresponding displacement from the other chambers through the other ports 18 and hence to the outlet. This flow through the meter causes the pistons to reciprocate and hence to rotate the crank-shaft. The valve 61 rotates with the crank-shaft and so connects each chamber alternately to inlet and outlet. The quantity of liquid passing through the meter is recorded by a mechanism coupled to the spindle 75. The piston stroke and hence the capacity of the meter is adjusted by screwing the stop 47 in or out as determined by the difference between the diameter of the rollers 42 and the spacing of the faces 37-37 (Fig. 5, not shown), on the pistons.