Effects of Air Valves and Pipework on Water Hammer Pressures
Publication: Journal of Transportation Engineering
Volume 123, Issue 2
Abstract
Many water hammer studies concentrate on the main pipeline and pump stopping. Important details can be overlooked. The rigidity of pipe walls, coatings, and surrounding fill on water hammer in pipes is evaluated. It is shown that backfill increases rigidity and celerity marginally, but pipe material is a major factor in water hammer pressures. The effect of air is to reduce wave celerity but increased surging can occur with some pipework configurations, particularly if air can be trapped. Pump startup can then result in severe water hammer. The correct selection of air valve size and standpipe used to minimize water hammer is discussed. The problem of air valves slamming shut during discharge is investigated and can be remedied with a nomograph. It is shown that large volume standpipes can reduce water hammer due to air valve slamming by providing an air cushion. Other problems of air release and sizing and positioning of air valves are discussed in order to reduce the problem of water hammer.
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References
1.
Albertson, M., and Andrews, J. S. (1970). “Transients caused by air release.”Control of flow in closed conduits, Colorado State Univ., Fort Collins, Colo., 315–340.
2.
Andrews, J. S. (1971). “Water hammer due to air exhaustion,” MS thesis, Colorado State Univ., Fort Collins, Colo.
3.
Glass, W. (1980). “Cavitation and corrosion in pumping main.”Proc., 3rd Int. Conf. on Pressure Surges, BHRA, Cranfield, England, 401–414.
4.
Kolp, D. A. (1968). “Water hammer generated by air release,” MS thesis, Colorado State Univ., Fort Collins, Colo.
5.
Lescovich, J. E. (1972). “Locating and sizing air release valves.”J. AWWA, 64(7), July, 457–461.
6.
Martin, C. S. (1976). “Entrapped air in pipelines.”Proc., 2nd Int. Conf. on Pressure Surges, BHRA, Cranfield, England, 2–15.
7.
Parmakian, J.(1950). “Air inlet valves for steel pipelines.”Trans., ASCE, New York, N.Y., 115(2404), 438–444.
8.
Parmakian, J. (1963). “Water hammer analysis.” Dover Publications, New York, N.Y.
9.
Stephenson, D.(1967). “Prevention of vapour pocket collapse in a pumping line.”Trans., SA Inst. Civ. Engrs., Johannesburg, South Africa, 9(10), 255–261.
10.
Stephenson, D. (1989). Pipeline design for water engineers, 3rd Ed., Elsevier, Amsterdam, The Netherlands.
11.
Stephenson, D., and Graham, N. (1983). “Water supply to Namaqualand.”Proc., ASCE Conf. on Pipelines in Adverse Envir., ASCE, New York, N.Y.
12.
Tullis, J. P., ed. (1970). “Control of flow in closed conduits.” Proc. Inst., Fort Collins, Colo.
13.
Tullis, J. P. (1989). “Chapter 10: Column separation and trapped air.”Hydraulics of Pipelines. John Wiley & Sons, Inc., New York, N.Y.
14.
Van Vuuren, S. J. (1989). “Induced pressure in pipelines resulting from fast release of air,” PhD thesis, Univ. of Pretoria, Republic of South Africa.
15.
Wilkenson, D. L.(1986). “The motion of large air bubbles in ducts of moderate slope.”J. Hydr. Res., 24(3), 157–170.
16.
Wisner, P. B., Mohsen, F. M., and Kouwen, N.(1975). “Removal of air from water lines by hydraulic means.”Proc., ASCE, New York, N.Y., J. Hydr. Div., 101(2), 243–257.
17.
Wylie, E. B., and Streeter, V. L. (1978). Fluid transients. McGraw-Hill Book Co., Inc., New York, N.Y.
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Copyright © 1997 American Society of Civil Engineers.
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Published online: Mar 1, 1997
Published in print: Mar 1997
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