| 摘要 |
A fluid-driven proportioning pump (10) for dispensing precise volumes of at least two different fluids (X, Y, 21). A drive cylinder (72) is divided into first and second drive fluid chambers (166, 168) by a drive piston (140) that is propelled in a reciprocating motion by a pressurized drive fluid (X). The drive cylinder housing is comprised of two identical cup-shaped housing halves (60) mutually engaged at the open ends thereof. Proportioning pistons (152, 154, 158, 160) extend from each face (162) of the drive piston (140) into proportioning cylinders (142, 144, 148, 150) in the drive fluid chambers (166, 168). An over-center mechanism is triggered by movement of the drive piston (140) at the extremes of the strokes of its reciprocating motion to operate valving (172,182) that admits the pressurized drive fluid (X) alternately into each of the drive fluid chambers (166, 168). A drive cylinder liner sleeve (206) is disposed on the interior of the drive cylinder (72) bridging the engaged mating surfaces (68) of the housing halves (60).
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