US 4,063,662 AGranted

Calibrating means for a microdispenser

AssigneeDrummond Scientific Company

InventorsMichael E. Drummond, John E. Robinson

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Abstract

Calibrating means for a microdispenser of the type wherein a plunger is operable to automatically draw a fixed volume of fluid into, and expel the liquid from, a precision capillary tube. The calibrating means includes a graduation marking on the capillary tube indicating the precise, predetermined quantity of fluid to be drawn into the tube. Calibration is effected by varying the degree of engagement of the microdispenser end cap with the microdispenser barrel, which effects corresponding longitudinal movement of the plunger with respect to the capillary tube until the outer terminal thereof is aligned with the graduation marking on the capillary tube. Friction means are provided for preventing accidental movement of the end cap after the calibration adjustment has been made.

Claims10

Dependent claims

A microdispenser having calibrating means, comprising:

a. a cylindrical barrel having an axial bore,
b. a removable end cap having a portion frictionally engaged with one end of said barrel,
c. a plunger assembly movable longitudinally through said cylindrical barrel and end cap,
d. means for urging said plunger assembly in the direction of said end cap,
e. stop means on said plunger assembly engageable with said end cap for limiting the longitudinal movement of said plunger assembly through said end cap,
f. tube means,
g. means for positioning said tube means in the end of said cylindrical barrel opposite the end cap, to receive said plunger assembly,
h. indicia means on said tube means for indicating the amount of fluid to be drawn into said tube means,
i. said removable end cap being longitudinally relocated with respect to said cylindrical barrel, for effecting corresponding longitudinal movement of said plunger assembly in said tube means, to align one end of said plunger assembly with the indicia means on said tube means, whereby a predetermined, precise volume of fluid is delivered upon actuation of the plunger assembly, and
j. locking means engageable with said end cap for maintaining the latter in fixed position with respect to said cylindrical barrel.

7 more elements

A microdispenser having calibrating means comprising:

a. a cylindrical barrel having an axial bore,
b. an end cap threadedly engaged with one end of said cylindrical barrel,
c. a plunger assembly movable longitudinally through said cylindrical barrel and end cap,
d. spring means for urging said plunger assembly in the direction of said end cap,
e. stop means on said plunger assembly engageable with said end cap for limiting the longitudinal movement of said plunger assembly through said end cap,
f. a capillary tube,
g. means for positioning said capillary tube in the end of said cylindrical barrel opposite the end cap to receive said plunger assembly,
h. a graduation mark on said capillary tube for indicating the amount of fluid to be drawn into said capillary tube,
i. said removable end cap being longitudinally relocated with respect to said cylindrical barrel, by threading said end cap into or out of said cylindrical barrel, for effecting corresponding longitudinal movement of said plunger assembly in said capillary tube, to align one end of said plunger assembly with the graduation mark on said capillary tube, whereby a predetermined, precise volume of fluid is delivered upon actuation of the plunger assembly, and
j. locking means engageable with said end cap for maintaining the latter in fixed position with respect to said cylindrical barrel.

7 more elements

Dependencies are inferred from the claim text.