[li] Patent Number: 4,648,533 [45] Date of Patent: Mar. 10,1987
3,759,424 9/1973 Maddock 222/309
3,785,526 1/1974 Shinn 222/14
4,055,281 10/1977 Rosen et al 222/309
4,169,405 10/1979 Tsunemoto et al 92/13.6
4,273,261 6/1981 Krueger 222/135
4,477,232 10/1984 Mayer 417/342
Primary Examiner—F. J. Bartuska
Assistant Examiner—Nils Pedersen
Attorney, Agent, or Firm—Dorsey & Whitney
[57] ABSTRACT
An electronically controlled, pneumatically actuated pumping system is provided that is especially designed for the precision dispensing of liquids. The system includes a positively actuated inlet valve, and a smalldiameter, long-stroke pumping piston that is physically stopped at each end of its stroke. The unique inlet valve and piston enable the system to repetitively dispense metered volumes of fluid at better than one tenth of one percent accuracy. A unique calibration mechanism and detachable dispensing head allow for the rapid disassembly, cleaning, and reassembly of the system. An alternative embodiment of the pumping system incorporates a plurality of dispensing nozzles controlled by a single inlet valve and pumping piston combination. The dispensing unit may be shiftably mounted on a vertically oriented stand, and may be automatically shifted upwardly as fluid is dispensed to minimize splashing and atomizing of the dispensed fluid.
5 Claims, 8 Drawing Figures
