Design Problem in Inverted Siphon
Published on by Engr. Salah Ud Din, Deputy Director at Pakistan Council of Research in Water Resources in Non Profit
I have an inverted siphon for which losses are correctly calculated but the inlet in not submerged, i.e hydraulic seal is not provided.
My question is, will the siphon be pressurized? Will it pass design discharge to the outlet?
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- Pumps
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1 Answer
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Dear Sir,
If the inlet of an inverted siphon (= inverted U) is NOT submerged then ambient air will enter, break the vacuum (in the 180° top bend) and hence stop the water flow.
The flow in this siphon will resume unhindered (at normal hydraulic loss as calculated) when the inlet is fully submerged (up to the top of the siphon) AND when the outlet is NOT submerged (open to atmosphere). However when the outlet would be submerged as well, then the air in the siphon will be entrapped and get pressurized. If the inlet water level will be sufficiently high to overcome the increasing air pressure then water will flow at a reduced flow rate because it will be hindered by the entrapped pressurized air.
Hope this helps.
Regards, Bruno