PURPOSE: To detect residual liquid in a vessel by detectors and control the operation of a pump on the basis of outputs from the detectors.
CONSTITUTION: A liquid feed device comprises a vessel filled with liquid to be fed, a liquid feed pipe 10 whose one end is connected to the vessel, a pump chamber whose one end is connected to the other end of the liquid feed pipe and which has a wall face composed of a flexible material, and a liquid containing portion constituted of an outlet tube connected to the other end of the pump chamber. The device holds detachably the pump chamber. Further, the device has a pump-operating unit 6 which gives displacement to the wall face made of the flexible material to allow the volume of the pump chamber to be changed, a fixed portion having a groove, in which the outlet tube is inserted, and having a pinch valve means for holding and pressing the outlet tube except the outlet time of the liquid to be fed, and detectors 13, 14 for detecting the residues of the liquid in the vessel. Furthermore, the detectors 13, 14 are photoelectric sensors or electrostatic capacity type liquid level switches and have a control circuit 19 for controlling the operation of a pump in junction with outputs from the photoelectric sensors.
TOMITA TOMONOBU
SATO TAKEMASA
ONO GIICHI
