System for dispensing a known volume of fluid

• Main Authors: IOANNIDES; ANTONIS C, WILSON; JAMES S, PATEL; ASHOK
• Format: Patent
• Language: English
• Published: 31.05.1994
• Edition: 5
• Subjects: BLASTING; BOTTLES, JARS OR SIMILAR CONTAINERS; CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOIDCHEMISTRY; DISPENSING, DELIVERING OR TRANSFERRING LIQUIDS, NOT OTHERWISEPROVIDED FOR; HEATING; INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIRCHEMICAL OR PHYSICAL PROPERTIES; LIGHTING; LIQUID HANDLING; MEASURING; MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUIDLEVEL; MECHANICAL ENGINEERING; METERING BY VOLUME; OPENING, CLOSING; PERFORMING OPERATIONS; PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL; PHYSICS; POSITIVE DISPLACEMENT MACHINES FOR LIQUIDS; PUMPING OF FLUID BY DIRECT CONTACT OF ANOTHER FLUID OR BYUSING INERTIA OF FLUID TO BE PUMPED; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS; SIPHONS; TESTING; THEIR RELEVANT APPARATUS; TRANSPORTING; WEAPONS

A system for delivering measured amounts of liquid, such as reagents used in chromatography. Liquid is first moved under gas pressure from a reservoir, such as a reagent bottle, through a valve into a narrow pipe. It reaches a detector which, detecting its presence, closes the valve thus trapping an amount of liquid between the valve and the detector, this amount of liquid then constituting a 'unit' or 'pulse' of liquid. The movement of the valve is used to connect a gas supply which drives the 'unit' or 'pulse' out of the pipe to an ultimate destination, such as a chromatographic column. A further 'unit' or 'pulse' can then be moved into the pipe and this repeated so that delivery to the destination is made in a series of such 'units' or 'pulse'. By timing the delivery of one 'unit' or 'pulse', an amount less than one 'unit' or 'pulse' can be delivered by passing liquid into the pipe for less than the time taken to deliver one 'unit'. This can be used to make up a delivery which is not a unitary multiple of one 'unit' or to deliver a small amount of less than one 'unit'. No moving parts are involved and delivery of accurately measured amounts is achieved.