Aquaculture Engineering

Pumps - Points to be considered for design of pumping station_2

Unit 12 - Management of ponds

Pumps

Points to be considered for design of pumping station

• In order to keep the water in the pump whilst standing and to facilitate priming, a foot valve is necessary which should have an area of minimum two times the area of the suction pipe depending upon how much foreign matter is carried in the water. A foot valve should be used at the foot (supply end) of the horizontal suction line.
• Gate valves should be provided on discharge side. The gate valve should be placed after the cheek valve if any mainly to permit repairs to check valve.
• In order to prevent of entrance of living organisms and other foreign particles while pumping the water from a river or tidal creek etc., a strainer is generally fitted with the foot valve at the end of the suction pipe, strainer should be at least 0.60 m away from the sides and bottom of the river bed. The strainer should have a total area of holes at least equal to four times the area of the suction pipe. Where no strainer is necessary,the suction pipe should preferably have bell mouth entry.
• In order to reduce running cost it is desirable to install pumps unequal capacities e.g one-third and two-third of the total flow desired which will work according to variation of demand.

• The largest pump and motor unit should be provided in duplicate as stand by.
• Auxiliary power units such as diesel generating sets (DG set) of required capacity should be provided to meet emergencies and break down of the power.
• As far as possible separate suction intake should be provided for each pump. If not tapering header with Y-branches should be provided.
• Flexible coupling should be provided to facilitate placing and replacing flanged pipe.
• The suction line should slope towards the source of water supply, which will permit draining the line and will avoid air pockets.