Document Type and Number:
Japanese Patent JPH0366516
Kind Code:
B2
Abstract:
PURPOSE:To prevent residual drops from falling down from a tip end of a discharge portion at any steps except a predetermined dropping step after discharge of liquid by a simple mechanism and thereby to provide superior quantative performance and repeatability, by using a special plunger pump with no check valve. CONSTITUTION:A plunger 25 is formed with a cut-away groove 26 axially extending to a lower end thereof at a part of a surface thereof. The plunger 25 is reciprocatably moved in a cylinder 22 by rotation of a pulse motor 29, which is rotated in both directions by receiving a signal from a control unit 28, through a rack 27 and a pinion 30. Further, the plunger 25 is connected through a spline 31 provided at an upper end thereof to a pulse motor 32, so as to permit slidable rotation thereof, thus forming a special plunger pump. With this arrangement, after a predetermined amount of liquid is discharged, the plunger 25 is retracted by a predetermined amount under condition such that a discharge hole 24 is opposed to the cutaway groove 26, so as to draw residual liquid at an end of a discharge portion 36 into the inside of the discharge portion 36. Thus, in the event that residual drops are generated at a tip end of the discharge portion 36, they are prevented from falling down at any steps except a predetermined dropping step by a simple device, thereby providing high quantative performance and repeatability.
Inventors:
FUKUOKA ISAMU
Application Number:
JP3196583A
Publication Date:
October 17, 1991
Filing Date:
February 28, 1983
Export Citation:
Assignee:
DENKI KAGAKU KEIKI KK
International Classes:
F04B53/14; F04B7/06
Next Patent: JPH0366517