APPARATUS FOR DISPENSING MEASURED BATCHES OF LIQUID

摘要

Apparatus for dispensing measured batches of liquid have hitherto employed metering pumps which can dispense accurately but are difficult to clean due to their complexity, or analogue meters which cannot dispense small quantities accurately due to their slow response. Apparatus which can dispense batches of any quantity with great precision and is easy to clean comprises a tank (30) containing liquid at a substantially constant pressure for supply to a batch dispensing on/off valve (44) by way of a digital mass flow meter (42), and a computer (48) for controlling the valve in accordance with a soft-ware programme and with information received from the meter. The tank is pressurised by the controlled supply or release of gas through a valve (36). The computer interacts with the valve (44) and the meter (42) by way of electro-pneumatic interfaces (50).