GB930377A - Improvements in or relating to metering and dispensing systems - Google Patents

Abstract

930,377. Mixing liquids in definite proportions. A. L. KRAFT. Dec. 29, 1959, No. 44091/59. Class 86. [Also in Groups XXVIII and XXIX] In a device for metering and mixing two liquids, e.g. a resin and a catalyst, in a predetermined but adjustable ratio, the liquids are pumped by diaphragm pumps the displacement of which is controlled by oil-loaded reciprocating pistons, the cross heads of which are connected to a common swinging link; the position of the cross-heads on the link determines the ratio of the liquids. In Fig. 1 resin in the pressurized reservoir 1 is forced by the air pressure into the chamber 5 (the valve 4 being open and the valve 9 closed) and deflects the flexible diaphragm 8, thus displacing oil from the chamber 7 and forcing the piston 12 downwards; the oil 25 on the other side of the piston 12 is forced into the reservoir 24 which is vented to atmosphere. On completion of the down stroke the valve 4 is closed, the valve 9 is opened, and the reservoir 24 is pressurized; the piston 12 is then driven upwards, displacing oil into the chamber 7 where the consequent deflection of the diaphragm displaces resin from the chamber 5 through the pipe 10 to the mixer 11. The catalyst contained in the reservoir 35 is pumped in precisely the same way by the operation of valves 41, 42 (which operate in synchronism with valves 4 and 9), diaphragm 38 and piston 43. The ratio of the liquids is controlled by the position of the pivots 18, 47 in relation to the fulcrum 16 of the swinging link 15; the ratio may be altered by adjusting the position of the reciprocating pumps in relation to the link 15, see Fig. 2 (not shown) The valves 4, 9, 32, 41, 42 are pneumatically actuated, see Fig. 4 (not shown), and Group XXIX; the air flow is regulated by electrically actuated valves 28, 30, 31 and the operation of the system is electrically controlled, see Fig. 3 (not shown). The system may be operated to give single or repeated shots, and will discharge automatically after a fixed time interval if not operated. The rate of delivery of the liquids may be altered by manual adjustment of the pressure regulator 151, and the total quantity delivered at each stroke by adjustment of the position of the stops 21, 22. The reservoirs and the mixer may be heated by thermostatically controlled immersion heaters. Additional liquids may be pumped by connecting further pistons to the swinging link 15; in a modification, Fig. 1A (not shown), three pistons are connected to a link in the form of a bell-crank. In another modification, Fig. 1B (not shown), only one liquid is pumped indirectly by a diaphragm pump according to the invention, the other liquid being pumped directly by a simple reciprocating pump operated by the swinging link.