Patent GB-750917-A (GB)
Title: Improvements in and relating to liquid dispensing apparatus
IPC: B67D7/74
Filed: 1953-07-17
Abstract: 750,917. Mixing liquids in flow. BECK & CO. (METERS), Ltd., and SOAR, H. G. July 9, 1954 [July 17, 1953], No. 19939/53. Class 86. [Also in Group XXVIII] In apparatus for delivering measured quantities of a mixture of liquids a primary metering chamber having a constant delivery volume and an auxiliary metering chamber having means for preselecting the volume of secondary liquid to be delivered thereby, are interconnected for simultaneous delivery to a common dispensing point whilst means is provided for extracting from the primary metering chamber during a delivery stroke the same volume of primary liquid as that of the secondary liquid required in the ultimate mixture. The apparatus in Fig. 1 comprises a reservoir 1 for petrol and a reservoir 2 for oil, the reservoir 1 being connected by a pipe 4 with a non-return valve 5 to a metering chamber 3, and the reservoir 2 being connected by a pipe 7 with a non-return valve 8 to an auxiliary chamber 6. Each metering chamber is in the form of a cylinder and contains a piston, the piston 9 in chamber 3 being provided with a port 11 and a non-return valve 12 to enable petrol to pass from one side of the piston to the other on the return stroke of the piston. A transfer port 17 in the discharge end of the cylinder 3 leads through a non-return valve 18 to a space 6a behind the piston 10 in the cylinder 6 and a delivery port 15 at the outer end of the cylinder 6 leads to a main delivery pipe 13 from the chamber 3. Both pistons 9, 10 move in unison. As the piston 9 moves forward some petrol is discharged through pipe 13, and some petrol moves into space 6a of the same volume as the volume of oil discharged from in front of the piston 10 through an outlet 13. The pistons 9, 10 are reciprocated by manual operation of a handle 24 which transmits motion through a crankshaft 23 to cranks 21, 25 associated with the pistons. The displacement of the crank 25 and hence the displacement of the piston 10 may be varied by the provision of a variable ratio gear 27, but the preferred means for operating the pistons is shown in Figs. 2 and 6. The crank 21 which reciprocates the piston 9 is squared on the crankshaft 23, on which is rotatably mounted a disc 35 with gear teeth 36 around part of its periphery, the toothed portion meshing with a driving pinion 37 keyed on a shaft 38 carrying the operating handle 24. The other portion of the periphery has a series of ratchet teeth 39, the series being separated at each end from the gear teeth by recesses 40, 41. The ratchet teeth are engageable by the nose 42 of a spring-urged pawl 43. Once the first ratchet tooth 39 adjacent either recess 40 or 41 has passed the pawl, reversal of the direction of rotation of the disc 35 cannot take place until the other recess has been brought under the nose of the pawl, whereby a full delivery stroke of the piston 9 is ensured at each dispensing operation. The disc 35 is formed with an arcuate slot 59 through which projects a pin 58 which connects together an arm 57 keyed on the crankshaft 23 and a link 56. The link 56 is pinned to a lever 45 having a pin and slot connection at its lower end to the rod of the piston 10. The lever 45 has an arcuate slot 48 enlarged at the bottom, the slot being engaged by a pin 50 carried in a lever 51. The lever works over a quadrant 53 formed with notches 54 engageable by a spring-loaded detent 55 on the lever 51. By selecting the appropriate notch for engagement by the detent, the stroke of the piston 10 may be varied as desired. With the parts in the position shown in Fig. 2, turning of the handle allows sufficient freedom of the disc 35 relative to the crankshaft 23 to allow the pawl nose 42 to ride over the first ratchet tooth 39, after which further rotation of the disc actuates the crankshaft to move the piston 9 in its delivery stroke. At the same time the lever 45 is swung on its fulcrum 50 to move the oil piston 10 in its delivery stroke. The pistons are prevented from operation when the level of liquid in a reservoir falls below a minimum or when the nozzle of the flexible delivery hose is on its rest. In both cases a detent 63, Fig. 7, prevents rotation of the driving disc 35 by engagement of its top in the recess 41. The detent 53 has a pin 65 projecting into the path of a weighted lever 66. When a float 68 in the reservoir falls too low, linkage 67 acts to raise lever 66 and thereby the detent 63. The pin 65 is also engaged by the slotted end 69 of a rod 70 pinned to a cross lever 71 the other end of which is adapted to terminate in the hook supporting the delivery hose. When the nozzle is resting in the hook the rod 70 is pulled up to lift the detent 63 into the obstructive position. In an alternative method of varying the relative strokes of the pistons 9, 10 a series of cams are mounted on a common shaft for simultaneous rotation by the camshaft 23, the cams having different lifts and being selectively engageable by a follower on a T-piece carried in the rod of the piston 10. By sliding the follower from one cam to another the ratio of the strokes of pistons 9 and 10 can be varied.