Butterfly Valve Pros, Cons and Chemical Industry Application Scenarios

1. Why are butterfly valves suitable for large-diameter pipelines?
Butterfly valves are widely used in large diameter pipelines.

The main reasons are as follows:
1) Short structure length
The butterfly valve body is relatively thin. Compared with gate valves and globe valves, the butterfly valve has a shorter structural length with the same caliber, which can save installation space.

2) Light weight
If a gate valve is used for a large diameter valve, the weight will be very large. The butterfly valve has a simple structure and light weight.
For large-diameter pipelines, butterfly valves are more convenient in installation, transportation, support and maintenance.

3) Lower cost
Under the same large diameter, butterfly valves are usually more economical than gate valves and ball valves. Especially in water systems and low-pressure gas systems, butterfly valves have obvious cost advantages.

4) Fast switching speed
The butterfly valve only needs to be rotated 90° to complete the switch. If a gate valve is used for a large diameter valve, the opening and closing time will be longer.
Butterfly valves can be quickly operated by handles, worm gear boxes, electric or pneumatic actuators.

5) Suitable for low pressure and large flow
Systems such as circulating water, cooling water, ventilation, and low-pressure gas usually have large diameters and low pressures. Butterfly valves are very suitable for such occasions.

2. Advantages of butterfly valve

1) Simple structure
Butterfly valve is mainly composed of valve body, butterfly plate, valve stem and valve seat. The structure is relatively simple and easy to maintain.

2) Small size and light weight
The butterfly valve has a short structure and is light in weight. Especially suitable for large diameter occasions.

3) Easy to operate
The butterfly valve only needs to be rotated 90° to switch.
A handle can be used for small diameters. For large diameters, worm gear boxes, electric actuators or pneumatic actuators can be used.

4) Have certain adjustment ability
Butterfly valves can change the flow area by changing the angle of the butterfly plate.
Can be used for some rough adjustment situations. But ordinary butterfly valves are not suitable for high-precision adjustment.

5) The cost is relatively low
In large diameter low pressure systems, butterfly valves are often more economical than other types of valves.

3. Disadvantages of butterfly valve

1) The butterfly plate is always in the flow channel
Even if the butterfly valve is fully open, the butterfly plate is still in the center of the pipe. So it will cause certain flow resistance.
This is also the difference between butterfly valves and full-bore ball valves and gate valves.

2) Ordinary butterfly valves have limited sealing capabilities
Ordinary soft seal butterfly valves are suitable for low pressure conditions.
If used for high temperature, high pressure or strong scouring media, the sealing material is easily damaged.

3) Not suitable for long-term adjustment of small opening with high pressure difference
When the butterfly valve has a small opening, the medium flow rate is high.

It is easy to appear:
· Scour
· Vibration
· Noise
· Cavitation
· Damage to sealing surface

4) Sensitive to installation direction and pipe stress
Improper installation of the butterfly valve may lead to eccentricity of the butterfly plate, uneven pressure on the valve seat, or stuck switch.
Especially for wafer butterfly valves, pay attention to flange centering and even tightening of bolts during installation.

4. Application scenarios of butterfly valves in chemical industry sites
Butterfly valves are widely used in chemical industry sites, especially in large-diameter low-pressure pipelines.

1) Circulating water pipeline
Circulating water systems are one of the most common application scenarios for butterfly valves.

Features are:
· Large caliber
· The pressure is not high
· High traffic
· The frequency of opening and closing is not high

Butterfly valves are suitable for use in circulating water pump inlets and outlets, heat exchanger inlets and outlets and system isolation.

2) Cooling water pipeline
Butterfly valves are also widely used in cooling water lines.

Commonly used for:
· Cooler inlet and outlet
· Heat exchanger bypass
· Equipment isolation
· Pipe network cut off

3) Fire water system
The diameter of the fire water system is larger, and butterfly valves are widely used.

Attention should be paid to butterfly valves in fire protection systems:
· Valve position status
· Switch indication
· Regular inspection
· Don’t turn it off by mistake
· There should be regulatory signals at important locations

4) Low pressure gas and ventilation system
Butterfly valves are also common in low-pressure gas, air, flue gas, and ventilation ducts. Especially in large-diameter air ducts, butterfly valves are lighter than gate valves and ball valves.

5) Steam and high temperature media
Ordinary soft seal butterfly valves are not suitable for high temperature steam. If used with steam, hot oil, high temperature gases, consideration should be given to:

· Metal hard seal butterfly valve
· Double eccentric or triple eccentric structure
· Pressure temperature level
· Sealing level
· Material applicability