Difference between eccentric design and concentric design butterfly valve

The butterfly valves is mostly used valves, with the advantage of low cost and compact design. Mainly they are divided into two kind of designs: eccentric and concentric.

Center line butterfly valve is 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 differences between center line butterfly valve and eccentric butterfly valve.

1. Center line butterfly valve disc is simple, just a disc, but eccentric butterfly valve disc also laminated seal ring.

2. The theory of center line is also easy, 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 metal-to-metal seat while center line butterfly is only soft seat, the soft seat ring is replaceable.

Application.

1. Center line 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 center line rubber seat can’t bear a high temp, but offset butterfly valve could work with hard seal design.