Pipe Installation
Water from pressure forebay flows through the pipe into the turbine. The pipes are installed after the
downstream of forebay and upstream of turbine valve as a connector between them.
Steel pipes welded with flange are commonly used in micro hydro power unit. The flange pads should be
placed in the up-straight position, in order not to reduce water cross-section. Nuts of the pipe joints should be
tightened gradually in a diagonal order.
Basic Requirements on Pipe Installation
Buy pipes according to the required diameter by the unit. Smaller diameter than the required diameters is
definitely not allowed! They should be straight and avoid any crooked part. The angle between pipe and
horizontal level of ground should not be less than 25°. If not, the pipes will be longer and the water head will be
decreased, which will lead to inadequate power output. It is better to use a horn-type mouth pipe as the water
inlet pipe which is installed in the wall of reservoir or forebay. The distance from the lower edge of horn-type
mouth to the bottom level of reservoir or forebay should be larger than 0.2 meters. The Inner diameter of
expansion joints should be the same as pipe diameter. But too many joints will cause loss in water head.
Anchored pier: Pressure is the highest in the joints of water inlet pipe and turbine nozzle, so anchored piers
made by stones or concrete are needed to be built to fix the metal pipe.
Supporting pier: Due to the weight of steel pipe itself and water, and pipes are long, they are easy to bend or
become deformed, so supporting piers must be added in their middle parts. The best installation place is the 5
joints between steel pipes.
Inspection after Pipe Installation
1. Whether there’s water leakage in the pipes or joints. If any, find out the reason and process it immediately.
2. Litters left while installation should be cleaned up to make sure water is unblocked.
3. Whether the pipes will become bended or deformed and whether they are firm enough after they bear the
water pressure. If any problems, it should be dealt with in time.