Selection of Valve Electric Actuator Models
Sep 26,2022Read More
MstnLand's series of wafer type concentric butterfly valves are widely used in water supply and drainage, building fire protection and other systems, especially in the fire pipeline and can be used in noncorrosive medium pipeline or equipment, for closure, connection and flow regulation.CONTACT
Gray cast iron/ Ductile cast iron
Mode of operation:
Water & Water Treatment, Power generation, Pulp & Paper, Municipal
Design & Manufacture:
API, ASME, ASTM, ANSI, BS, DIN, JIS, ISO, GB
Wafer-type butterfly valves are designed with 2 or 4 non-tapped centring holes around the valve body that align with the connected pipeline. The flange bolts are inserted through the bolt holes of the two pipe flanges and the centering holes of the butterfly valve. By tightening the flange bolts, the pipe flanges are pulled towards each other and the butterfly valve is clamped between the flanges and held in place. It's designed to clamp between two flanges in your pipeline. And cannot be used as pipe ends or end-of-line service. Lug-type butterfly valves have multiple threaded tapped lugs (also called "ears") over the entire circumference of the body. Each 2 sets of bolts connect to pipe flanges to each side of the bolt inserts without nuts. It suitable for end-of-line service under normal conditions.
Concentric butterfly valves are most basic butterfly valve design is commonly called a concentric or resilient-seated butterfly valve. In this valve type, the stem is centered in the middle portion of the valve disc, which is centered in the pipe bore. The valve conventionally has a rubber seat and relies on the disc having a high level of contact with the seat for an effective seal. During the 90 degrees rotation, the disc will contact the seat the earliest. They are designed with an excellent bi-directional sealing function and zero leakage well suited for tight shutoff and regulation of diverse mediums.
Concentric butterfly valves are widely used in water treatment and other industries, because of it's advantages: light weight, small size and easy for installation, low cost. But thanks to it's design, it's limited in many cases, and offset/eccentric butterfly valve could help. Below are some basic difference between concentric butterfly valve and eccentric/offset butterfly valve.
You could easily distinguish them from the appearance, because all the total different design structure.
1. Concentric butterfly valve disc is simple, just a disc, but eccentric butterfly valve disc also combined with disc seal, seal retaining ring, and retaining bolt.
2. The sealing of concentric butterfly valve is also simple, the disc touch the rubber seat directly, while eccentric butterfly valve with a additional laminated disc seal touched with a meat body seat.
3. Eccentric butterfly valve seat is meat while concentric butterfly valve is only soft seat, could be integral body seat or replaceable welded seat.
1. Concentric butterfly valve can only reach a pressure of 150LB/PN25, while offset butterfly could up to 600LB/PN100.
2. Temperature. Because of the different design of the seal structure, the concentric butterfly valve rubber seat can't bear a high temp, but eccentric/offset butterfly valve could work with hard seal design.
The advantages and disadvantages are apparently, and very easy to choose which one to use for a real condition. When the pressure is high, or requires a high temperature, must used a eccentric butterfly.