Explain Pelton Wheel

Pelton wheel:

In this article, we will learn about the Pelton Wheel. The Pelton wheel is a tangential flow impulse turbine. Spear is used where it is high pressure. Pelton
Below are the main parts of the wheel.

1. Nozzle and flow regulating arrangement
2. Runner & buckets
3. Casing
4. Deflector
5. Breaking jet.

1. Nozzle and flow regulating arrangement:

The nozzle is a cone-shaped tube. It is attached to the end of the penstock pipe and converts all the pressure energy into kinetic energy. The nozzle is fitted with a spear or conical needle inside the axle to move the wheel through the axle. The wheel rotates by controlling the size of the jet hitting the runner’s bucket by the spear in the nozzle. As the spear moves forward inside the nozzle, the amount of water hitting the runner decreases. As you move the Spear backward, the amount of water hitting the runner increases.

2. Runner and buckets:

The Pelton wheels runner is a circular disc mounted on the shaft. The edge of the wheel is fitted with a series of bucket s bolt in equal spacing. Generally, buckets are shaped like two semicircular cups stacked side by side. In the center of the bucket, the jet is divided by a sharp area called the splitter and the outer edge of the bucket. The shape of the bucket is set to deflect from 1.60 ° to 170 ° when the jet hits. Cast iron buckets are used in low-pressure areas and cast steel or bronze buckets.

3. Casing:

The casing is usually made of cast iron or steel plate. It doesn’t do anything about hydraulics. However, it is used for the following reasons:

1. To prevent spraying of water
2. Take the exit water to the tailrace on the right path
3. To protect the bucket from falling into any object

4. Deflector:

The deflector is a plate that is fixed at one end. It is connected to the speed control system by the lever. When the load on the turbine decreases, the governor drives the lever and puts the deflector plate in front of the buckets. So, the water on the bucket gets dumped. So that the Wheel speed also decreases.

5. Breaking jet:

When stopping the turbine, move the spear forward and close the nozzle or close the turbine’s inlet valve. Even so, the wheels’ inertia will rotate for a while. Therefore, to stop the turbine immediately, the nozzle is fitted in the casing and the jet is mounted on the back of the bucket.

Working:

The jet from the Reservoir reaches the nozzle through the penstock tube and emerges. Nozzle converts pressure energy into kinetic energy. The water from the Nozzle spins the runner into the jet in the form of a bucket. So that mechanical energy is formed. Water passing through the nozzle can be controlled by a spear regulator. Runner jet finishes the job and enters the tailrace.

Read Also: Principle Of Impulse Turbine and Reaction Turbine