- 57 Downloads
Flowmeters are tapered glass tubes which have a gradually increasing inside diameter in the upward direction. The gas flow to be measured enters the tube at the bottom and leaves the tube at the top (Fig. 22). The glass tube contains a free moving float as the indicator of the flow. This float rotates freely without touching the walls of the tube when actuated by a gas flow. The float reduces the free orifice of the tube by forming an annular gap with the glass tube’s wall. The higher the position of the float the wider the gap between float and wall. The pressure difference across the annular gap is the same for all positions of the float. The location of the float is determined through the equilibrium of the weight of the float and the pressure difference across the annular gap. This equilibrium requires a wider annular gap for a greater gas flow and, thus, a higher location of the float. The friction of the gas and the development of turbulence have an additional effect on the location of the float.
KeywordsUpward Direction Anaesthesia Machine Flow Control Valve Hyperbaric Chamber Descriptive Literature
Unable to display preview. Download preview PDF.
- Brooks Instrument Division, Hatfield, Pa. : Descriptive literature.Google Scholar
- Compressed Gas Association, Inc., New York, N.Y. : Draft of proposed minimum performance and safety requirements for components and systems of constant-flow anesthesia machines.Google Scholar
- Krohne, Fa., Duisburg: Descriptive literature.Google Scholar