Impulse turbines are situated to Parts of pelton wheel turbine,

In this type of turbine the operation is rather more like that of waterwheel. In the waterwheel water is directed into buckets which fill, impart rotational velocity by gravity and then empty to rise and collect more. The impulse turbine has ring of fixed nozzles that blast onto bucket type vanes of a rotating wheel. The pressure drop is achieved in the nozzle which is flared and not by the rotating stator. the de Laval spings at typically 30,000 rpm and is ineffiecient at using the steam energy.

Impulse turbines are situated to Parts of pelton wheel turbine

There are four major parts of the turbine

·        Nozzle and spear valve

·        Runner and buckets

·        Casing

·        Breaking jet

Nozzle and spear valve

The water strikes to the bucket of the turbine came from the nozzle. Spear valve is placed inside of nozzle. This valve is used for the throttling of waterflow automatically or manually with hand wheel.

During operation, if we want to control the flow of water, the only thing we need to do is to simply rotate hand wheel.

Runner and buckets

The runner of the turbine is the circular disc and on the periphery of runner, there are multiple buckets which are spaced equally. Every bucket is divided into two symmetrical parts and the wall between these two symmetrical parts is called splitter.

The design of bucket has prime importance. When water strikes at the bucket, splitter divides the water jet into two parts and deflect it with 160° or 170°.

For lab operation, buckets are made of plastic material but to generate power at higher level, cast iron, stainless steel or cast steel bronze is used according to the available head.

Casing

Whole assembly of pelton wheel turbine is enclosed in the casing. The main purpose of using casing is to give water the way to reach tail race after striking buckets.

Breaking jet

During operation, when we want to stop the turbine, we use breaking jet. By using this breaking jet, we can stop the runner of the turbine with the strike of water on the back of buckets.