The turbine installation comprising a propeller made of hollow barrel with very thin surface wall conically shaped which is very light in weight. The self weight of the propeller is made as much smaller as it can be able to with stand the stress of water pressure while revolving inside the water and that reduction of selfweight must be permitted by the design principle. The upper portion of the thin barrel constitutes the runner fitted with blades on its outer surface by means of welding or blades may be integrally cast with the whole propeller barrel if conditions permit. For microlight materials like - Teflon, GRP (glass fibre reinforced plastic) etc. the blades may be cast integrally or separately as runner blades. Joint for the runner with the propeller barrel is generally located at the blade"s base where the diameter of the barrel is maximum measured from the tip. The joint should be leakproof and strong enough to resist the stress of revolving thrust of water. Superfine quality of sealing material should be used to seal the joint. The advantage of using a joint for runner with the propeller barrel is that the runner blades can be replaced by new ones after being womout due to continuous use for long period. This replacement of runner blades from the main propeller barrel may reduce the cost of repair as because the wear and tear occurs particularly on runner blades due to cavitation problem. It is experimentally observed that the power and efficiency of propeller drastically increases with the decrease of self weight (mass) of the propeller. Therefore, lighter the propeller made with in the permissible design principle greater will be the power obtained with the aid of a very low static head of water. This turbine system requires very small plot of land to install the power plant with control room just by the side of river embankment. Installation cost is minimum compared to the other hydel plants.
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