Butterfly Valve
Butterfly valves are valves that control the opening and closing of the water flow and the adjustment of the flow rate by rotating the stem and thus the swing on both sides.
As a china manufacturer for butterfly valve, we can produce wafer type butterfly valve, lug type butterfly valve ,flange butterfly valve and groove ends butterfly valve.
Why butterfly valve?
The butterfly valve is a valve that rotates the valve stem to drive the valve disc to rotate. The valve only needs to rotate 90 degrees from open to closed, or from closed to open, so the stroke of the switch is very short, so that it can be open or close quickly. If it is to adjust the flow, you only need to rotate the valve disc at a small angle (≤90 degrees) according to the capacity of the flow required. Therefore, compared with gate valves, globe valves, etc., the open or close speed of butterfly valves is much faster.
Butterfly valves can be installed vertically or horizontally as required
Butterfly valves can be divided into wafer butterfly valves, lug butterfly valves, flange butterfly valves or groove connect butterfly valves, with flexible connection methods and short structural lengths
When the butterfly valve is fully open, only the valve stem produces flow resistance. Compared with globe valves, ball valves, etc., the fluid resistance of butterfly valves is very small.
The sealing ring of the butterfly valve can be replaced, and the maintenance is simpler.
The valve disc can be covered according to customer requirements, so it is suitable for corrosive media, but pay attention to the rubberized valve disc or valve body, the resistance is very large, so there is a greater torque
According to the characteristics of the fluid or gas, the material of the valve disc and sealing ring can be changed, and there are many options, for example, the valve disc can be nickel-plated on the surface of ductile iron, plastic-sprayed on the surface of ductile iron, stainless steel, etc., and the sealing ring can be made of EPDM, NBR, Viton and other options are available to meet the needs of different fluids or gases.
The operation mode of the butterfly valve is also very rich, you can choose lever, worm gear, electric or pneumatic.
What is the problem with the butterfly valve?
Although butterfly valves have many advantages, there are also many problems
1,For viscous fluids, fluids or gases that are corrosive or contain hard solid particles
During operation, viscous and corrosive fluids tend to wash away the disc of the butterfly valve, which will cause the disc to be damaged rapidly and lose sealing function. If you are dealing with high viscosity liquids, you may want to consider a more robust ball valve or gate valve rather than a butterfly valve.
The fluid or gas containing solid particles will erode the valve disc, thus destroying the valve disc.
2,Cavitation and Choked Flow
When the valve is in the open position, it does not provide a full port due to the disc. In certain applications, this can lead to excessive debris buildup around the valve, cavitation problems, or the possibility of blocked flow. If full port is required, a ball valve may be a better choice
3,No high pressure throttling
Butterfly valve openings are limited to between 30-80 degrees making them very effective in low pressure throttling applications. However, higher pressures may give better results with globe valves.
Butterfly valve vs gate valve
1, Butterfly valve and gate valve are both important parts of a pipeline to cut off fluid or gas, but butterfly valve has one more function compared to gate valve, that is, it can be used as a flow regulator, i.e. butterfly valve can be used to reduce the flow rate when it is not fully open.
2, Butterfly valve is through the rotation of the valve disc around the valve stem to achieve the opening and closing of the valve, while the gate valve is through the up and down movement of the valve disc driven by the valve stem to achieve the opening and closing of the valve, so the stroke of the butterfly valve is shorter and the opening and closing is more rapid.
3, in terms of design, the butterfly valve has a simpler construction, so the cost is lower compared to the gate valve and has a price advantage.
4, The butterfly valve’s valve disc is designed with a scraping function, so it is suitable for fluids and gases containing suspended particles. The butterfly valve disc and sealing ring are made of more diversified materials, such as viton and PTFE seals, which are resistant to corrosion and high temperatures, etc. If required, the disc and body of the butterfly valve can also be covered with rubber, which makes it suitable for corrosive and high & low temperature fluids and gases.
5, In terms of connection, butterfly valves are available in a variety of designs such as wafer type, lug type, groove type, butt-weld type and flange type, so that they can be flexibly selected according to the specific working conditions, especially when the installation space is small, compared to the gate valve, there are greater advantages
6, for larger size pipelines, butterfly valves are usually chosen, because the structural characteristics of gate or globe valves in large size pipelines determine that the valve will be very large, very heavy and high cost
What pressure can butterfly valve afford?
For resilient seated or metal seated , ductile iron body butterfly valves can withstand a maximum working pressure of 2.5 Mpa .
If higher pressures are required, then steel material and metal seated butterfly valves are required.
