Development of Automatic Air Evacuation System in Siphon Pipe and Characteristic of Operation

• Published in: Transactions of The Japanese Society of Irrigation, Drainage and Reclamation Engineering Vol. 1994; no. 173; pp. 101 - 109,a2
• Main Authors: JIANG, Hua Ying, NISHIYAMA, Souichi, KAWANO, Hiroshi, MINAMI, Nobuhiro, MAOKA, Juichi
• Format: Journal Article
• Language: English; Japanese
• Published: The Japanese Society of Irrigation, Drainage and Rural Engineering 1994
• Subjects: Air evacuation; Irrigation reservoir; Pipeline; Siphon
• ISSN: 0387-2335; 1884-7234
• DOI: 10.11408/jsidre1965.1994.173_101

In Kagawa prefecture, the annual precipitation reaches only about 1100 mm.So from the olden times, many irrigation reservoirs were constructed for agricultural water use. In pipeline systems which are connected with irrigation reservoirs, if the siphon pipe systems can be used, the construction cost of irrigation systems can be greatly reduced.Because there is no need to excavate the embankment of irrigation reservoirs. But the accumulation of air is particularly severe problem in a siphon type of pipeline system, since the pressure at the top of the siphon is less than atmospheric pressure.This air seriously reduces the pipeline capacity of transporting water.In the worst case, the water flow in siphon system is stopped. Accordingly, if we use the siphon system under the negative pressure, it is necessary to evacuate the air from the pipeline for the safety of the flow.Conventionally, the vacuum pump was used to remove the air accumulated in the siphon pipe.But in the case of the vacuum pump method, the water pump is necessary for initial priming of the siphon system and the vacuum pump is not easy for maintenance, so that the vacuum pump method has many disadvantages. The authors made the new automatic system to remove from the siphon pipe without using the vacuum pump and also made an analysis for the design of the new method of air removal system. This system of air removal contributes to the promoting of irrigation system of pipeline in the district of many irrigation reservoirs.