Butterfly Valve VS Ball Valve

How does a Ball Valve Work?

A ball valve is used to permit flow accross a pipe line, there is an inlet side and outlet side. Open Position allows the water to pass through the valve and the Closed Position stops the flow. There is a Ball inside the valve which hs a hollow, the stem attached the ball in the valve and the handle is bolted in the other hand and valve is closed and open with the help of this handle. The handle lies flat in alignment with the flow when open, and is perpendicular to it when closed, making for easy visual confirmation of the valve's status.
 

How does Butterfly Valve Work?

A butterfly valve is used isolate and regulate the flow of the water. The Disc placed in the ceter opens and closes is connected with the hinges. With the help of the operator the disc of the valves is opend or closed. When the valve is installed in a pipe line the water in the pipe is allowd to flow from the valve, keeping it in open possition, the water flows from the either sides of the disc. When the required amount of water is passed the disc of the valve is closed with the help of the operater to stop the flow of the water in the pipe line.
 

Differences in Butterfly Valve and Ball Valve:-

Butterfly Valve is used for Isolating and Regulating of the flow this machenism is in a form of a disc which is smilar to Ball Valve which allows to quich switch off, but Butterfly Valves are more favorite as it is lower in cost and lighter in weight than the Ball Valve.

Butterfly Valves being lighter in weight it requires less support. The disc is positioned in the center of the pipe and the rod is connected to an actuator outside or on top of the valve, ratating the actuator turns the disc paralle or perpenducular to the flow. In the Ball Valve the dis is always present in the with in the flow therefore preassure drop is always induced in the flow.
 

Advantages Of Ball Valve

1. Low pressure drop, tisght shut off, quarter turn operation, east to maintain, low tourque. They are small in size and low in weight.
2. Excellent ease to operate.
3. Maintains and manages great volume, high temp flow and high pressure.
4. Strong development and long support life.
5. Able to operate without side loads.
6. Does not require lubrication.

Disadvantages of Ball Valve

1. PTFE seats are subjected to extrusion if the valve is used for throttling. fluid trapped in the ball in the closed position may cause problem of build up of vapour pressure and corrosion.
2. They are not suitable for sustained throttling applications.
3. In slurry or other applications, the suspended particles can settle and become trapped in body cavities causing wear, leakage or valve faliure.

Advantages Of Butterfly Valve

1. They are suitable for large valve applications.
2. Compact, lightweight desing.
3. The maintenance cost are usually very low.
4. Pressure drop across a butterly valve is small.
5. Used with chemical or corrosive media.
6. Good flow control.
7. Low pressure drop.

Disadvantages of Butterfly Valve

1. Difficult to clean.
2. High torque required to control.
3. Prove to cavitaion at lower flows.
4. Throtlling limited to low differential pressure.
5. Potential for cavitations and choke.
6. Unguided disc movement is affected by flow turbulence.