Fluid-driven apparatus for dispensing plural fluids in a precise proportion

摘要

A fluid-driven proportioning pump for dispensing precise volumes of at least three different fluids includes a drive cylinder housing a correspondingly formed drive piston which divides the drive cylinder into first and second drive fluid chambers and is propelled in a reciprocating motion by a pressurized drive fluid. The housing for the drive cylinder is comprised of two identical hollow housings mutually matingly engaged at the open ends thereof. The face of the drive piston is provided with projecting proportioning pistons which extend into proportioning cylinders that open into each drive fluid chamber. An over-center mechanism triggered by movement of the drive piston at the extremes of the strokes of the reciprocating motion thereof operates valving that admits the pressurized drive fluid into turn it of the drive fluid chambers. The over-center mechanism is activated by hoop springs and is housed entirely within the drive cylinder. A drive cylinder liner sleeve is disposed on the interior of the drive cylinder extending at least to the extremes of movement of the drive piston and bridging the engaged mating surfaces of the two identical cup-shaped halves of the proportioning pump housing.