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.


Upward Direction Anaesthesia Machine Flow Control Valve Hyperbaric Chamber Descriptive Literature 
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  1. Bishop, C., Levick, C.H., Hogdson, C.: A design fault in the boyle apparatus. Brit. J. Anaesth. 39, 908 (1967).PubMedCrossRefGoogle Scholar
  2. Brooks Instrument Division, Hatfield, Pa. : Descriptive literature.Google Scholar
  3. Clutton-Brock, J.: Sticking rotameters. Brit. J. Anaesth. 42, 722 (1970).CrossRefGoogle Scholar
  4. 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
  5. Eger II, E.I., Epstein, R.M.: Hazards of anesthetic equipment. Anesthesiology 25, 490–504(1964).PubMedCrossRefGoogle Scholar
  6. Hylton, R.R., Irwin, R.H., Guadagni, N.: Anesthetic flowmeter sequence — a cause for hypoxia. Anesthesiology 24, 396–397 (1964).CrossRefGoogle Scholar
  7. Katz, D.: Recurring cyanosis of intermittent mechanical origin in anesthetized patients. Anesth. Analg. 47, 233–237 (1968).PubMedCrossRefGoogle Scholar
  8. — Increasing the safety of Anesthesia machines. Anesth. Analg. 48, 242–245 (1969).PubMedCrossRefGoogle Scholar
  9. Kelley, J.M.: The improperly calibrated flowmeter — another hazard. Anesthesiology 33, 467–468 (1970).CrossRefGoogle Scholar
  10. Krohne, Fa., Duisburg: Descriptive literature.Google Scholar
  11. Lomanto, Ch., Leeming, M.: A safety signal for detection of excessive anesthetic gas flows. Anesthesiology 33, 663–664 (1970).PubMedCrossRefGoogle Scholar
  12. Ross, E. D. T. : Accidental hypercapnia and rotameter bobbins. Brit. J. Anaesth. 40, 45 (1968).PubMedCrossRefGoogle Scholar
  13. Severinghaus, J.: Hyperbaric oxygenation: anesthesia and drug effects. Anesthesiology 26, 812 Special Article (1965).CrossRefGoogle Scholar
  14. Smith, Th.C.: Calibration of gas flowmeters with the bubble burette. Anesthesiology 33, 553–555 (1970).PubMedCrossRefGoogle Scholar
  15. Walts, L. F. : Malfunction of a new anesthetic machine. Anesthesiology 25, 867 (1964).PubMedCrossRefGoogle Scholar
  16. Ward, C.S.: The prevention of accidents associated with anaesthesia apparatus. Brit. J. Anaesth. 40, 692–701 (1968).CrossRefGoogle Scholar
  17. Weis, K.-H., Schreiber, P. J. : Konzentrationsmessungen am Fluotec und Halothan-Vapor in der Überdruckkammer. Anaesthesist 16, 357–359 (1967).PubMedGoogle Scholar

Copyright information

© Springer-Verlag Berlin · Heidelberg 1972

Authors and Affiliations

  • Peter Schreiber
    • 1
  1. 1.Department of AnesthesiologyUniversity of AlabamaBirminghamUSA

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