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| Typical Number in Hospital: 500 | Cost Bands: 1 | References: 2 |
These are commonly used to monitor and set oxygen flow in oxygen therapy apparatus. They consist of a needle valve to control flow and a tapered tube containing a ball which is driven up the tube to a height depending on the flow of gas past it. The tube is triangular in internal section or trefoil. The mode of operation is similar to that of a rotameter but accuracy is less (typically 10% at 10 l/min). The scale engraved on the tube is read at the centre of the ball. The need for the tube to be exactly vertical is less than with a rotameter. They are usually connected to the gas source (pipeline connector or cylinder) with a connector which cannot be inserted into the wrong gas source. These are used in large numbers in hospital wards.
Content and Design Copyright 2000 Dr. Malcolm C Brown. See Title Page for more details