公开(公告)号：US3901653A

公开(公告)日：1975-08-26

申请号：US38090873

申请日：1973-07-19

Applicant: BECKMAN INSTRUMENTS INC

Inventor： JONES ROBERT H ,  HUMMEL CHARLES V

IPC: G01N1/00 ,  F04F1/00 ,  G01N1/10

CPC classification number: G01N35/1095

Abstract: A device for dispensing a predetermined quantity of a liquid sample has an S-shaped dosing tube with an inlet connected through a collecting vessel to an air supply for receiving air during vacuum, vent and pressure portions of an operation cycle and an outlet connected to deliver the sample to a recipient system. A supply tube connected to receive liquid from a source such as a process stream provides liquid to the dosing tube, during the vacuum portion of the cycle, through a transfer vessel operatively connected between the inlet and outlet. Liquid enters the transfer vessel from the supply tube at a level above that of liquid remaining in the dosing tube from a previous operation cycle. A drain tube is connected through the collecting vessel to the dosing tube to remove liquid in excess of the predetermined quantity prior to dispensing the sample. A liquid seal is provided in the tubes to prevent air escape and maintain pressure in the tubes. The device is especially adaptable to deliver a fresh sample for each operation cycle which is not mixed with liquid remaining in the device from a previous sample. Each cycle of operation is controlled by a programmer which provides signals to the air supply and the supply tube during vacuum, vent and pressure portions of each operation cycle.