GB1281349A - Fluid sampling system - Google Patents

Abstract

1281349 Sampling liquids E I DU PONT DE NEMOURS & CO 14 Aug 1969 [16 Aug 1968] 40672/69 Heading B8N [Also in Divisions B1 and F1] A fluid sampling system (Fig. 5) comprises a sample source (not shown), a pump 75 for withdrawing fluid from the sample source via probe 74 and an intake-output valve assembly 73, assembly 73 comprising (Fig. 2), a valve chamber 28, first and second ports 37, 38 first port 37 being connected to the pump and second port 38 being communicable with the sample source and in communication with the valve chamber 28 in all positions of the valve, valve closure member 30 mounted on support means 31, 32 and reciprocable within the valve chamber between a first position in which port 37 communicates with the valve chamber as shown and a second position in which the closure member 30 isolates port 37 from the chamber, the combined volume of closure member 30 and support means 31, 32 within the chamber varying with displacement of member 30 between its first and second positions to provide a positive predetermined pumping action, and hence more precise metering of a sample taken into probe 74 and discharged from the probe. Support means 31, 32 may be operated manually or otherwise and may be spring loaded as shown. The system of Fig. 5 includes buffer liquid source 79, wash liquid source 83, debubblers 82, 84 and non-pumping valves 78, 77 which operate to allow transfer of liquids from 79, 83 to cylinder 81 of piston-cylinder pump 75 for discharge through probe 74 when valve 73 is open. The " non-pumping valve " 77 or 78 (Figs. 1A, 1B, not shown) has construction similar to that of valve assembly 73, but the closure member (13) has support rods (14, 15) of equal diameter. Movement of the member (13) within the valve chamber produces no pumping action. The non-pumping valve has two opposed outlet channels 21, 22 allowing flow through the valve even when the outlet passage from the valve chamber is closed. Pump 75 (Fig. 4, not shown) comprises cylinder 59, piston 60 and means 61 for driving the piston. Piston 60 has mushroom-shaped deformable end cap 64 with its stem protruding into hollow shaft 66. Screw shaft 68 connects deformable cap 64 and rear end plug 67; when the shaft cap wears so allowing leakage, shaft 68 is turned and the stem of cap 64 is drawn further into hollow shaft 66, so forming the hood of the mushroom into tighter contact with plug 65. The pump is cleaned after use (a) by drawing a cleansing fluid through channel 62 into the pump chamber 63, and (b) by admission of cleansing fluid on the forward stroke of the piston through one-way valve 69 into shaft 66 and through outlets 70 into the space behind the piston cap and removal of the fluid through valve 72 on the return stroke.