Butterfly valve is an important valve type for fluid control. In the selection process, the correct selection of valve size is crucial because it directly affects the performance, safety and economy of the system. Let us discuss the applicable occasions and the key points of size selection of butterfly valves.
1. Pipe System Flow Needs
According to the flow needs of the pipeline, selecting the appropriate butterfly valve size can ensure that the fluid in the pipeline is effectively controlled. Thick pipes require large-sized butterfly valves, otherwise they will cause blockages.
2. Pipe Pressure
The size of the butterfly valve has a direct impact on the fluid pressure. Typically smaller butterfly valves may be suitable for lower pressure systems, while larger butterfly valves are suitable for high pressure systems. However, a butterfly valve that is too small relative to the pipeline may cause pressure loss. On the contrary, passing the valve will cause energy waste. Therefore, using appropriate dimensions can reduce pressure loss and improve energy efficiency.
3. Flow Rate of Medium
The flow rate of the medium in the pipeline will also be affected by the size of the butterfly valve. Small-sized butterfly valves can cause media clogging, resulting in pressure reduction. Large-sized butterfly valves will cause the medium flow rate to be too fast, affecting the stability and safety of the pipeline system.
4. Type selection of butterfly valves
Butterfly valves have many connection types, such as wafer butterfly valves, flange butterfly valves, threaded butterfly valves, welded butterfly valves, etc. Each type has its specific scope of application and advantages, which should be determined according to the specific requirements. Application selects appropriate type and size.
a) Among clamp connections, flange connections, threaded connections, and welded connections, the first two are the most commonly used. The wafer butterfly valve is suitable for DN15-DN2000 pipelines, while the flange butterfly valve is suitable for DN40-DN3000 pipelines.
b) Threaded connection is suitable for valves with DN≤50mm
c) The size of the welded connection is between DN80-DN2000. It is commonly used under harsh conditions and is more reliable than flange connection. The disadvantage is that the butterfly valve cannot be replaced.
5. Safety
When selecting the size of the butterfly valve, you also need to consider the safety of the system. A butterfly valve that is too small cannot meet the maximum flow demand, and may also cause the pipeline to burst or leak due to the pressure passage. Of course, being too large will also lead to loose sealing and leakage.
6. Fluency of Opening and Closing
6.1 As can be seen from the above, a small-sized butterfly valve will cause the pressure to increase, which means that the pressure on the butterfly plate will also increase, the torque will increase, and the output torque of the actuator will also increase. If the output torque of the actuator is less than the closing torque of the butterfly valve, the butterfly valve will not close.
6.2 If the size of the butterfly valve is too small, it will also cause the butterfly valve to get stuck.
7. Manufacturing Cost
Cost is an important factor in butterfly valve size selection. A properly sized butterfly valve can improve cost performance, reduce energy consumption, reduce maintenance costs, and extend the service life of the system, thereby saving money and resources for the enterprise.
Therefore, the correct selection of the size of the butterfly valve requires comprehensive consideration of factors such as pipeline system flow demand, pipeline pressure, medium flow rate, butterfly valve type, system safety, and manufacturing cost to ensure the operating efficiency, safety and stability of the system.