The ball valve is composed of valve:body,ball,stem,sealing ring,packing, etc., and the butterfly valve is composed of valve:body,disc,stem,packing,etc.We will find following differences between ball valve and butterfly valve,and these are main points:body’s type,working conditions,operation,size’s limitation,features,and cost for two kinds of valve.
The ball valve have many kinds type include:ball valve generally have floating ball valve,fixed ball valve,one-piece ball valve, two-piece ball valve, three-piece ball valve, soft sealing ball valve,hard sealing ball valve, forged steel ball valve, flange ball valve, welding ball valve, threaded ends ball valve, thread ball valve , card ball valve, electric ball valve, pneumatic ball valve, hydraulic ball valve, gear ball valve, eccentric ball valve, top-mounted ball valve, stainless steel ball valve, carbon steel ball valve, cast steel ball valve, fluorine-filled ball valve, discharge ball valve, high temperature ball valve, water and electric ball valve , large diameter ball valve, small diameter ball valve, plastic ball valve etc,the size could be as small as DN6, as large as DN1000, and pressure from 0.6MPA-32MP. The butterfly valve has poor pressure resistance, generally within 2.5MPA, and in the case of reverse pressure, the back pressure effect is not very good. There is also the diameter of the butterfly valve is generally a large diameter, the minimum is generally DN50, but its maximum diameter can be achieved DN3000, so generally in the large pipeline is inseparable from the butterfly valve. The cost of the ball valve is higher and the cost of the butterfly valve is lower.
The ball valve is a valve that realizes the switch sealing by the ball, and the butterfly valve is a butterfly plate as the opening and closing disc.The ball valve has good pressure resistance, large flow, and full through flow, but its high cost is ball valve’s shortcoming. The butterfly valve has poor pressure resistance, and is generally used on a 10-16 kg pressure pipeline, but its advantage is that it is cheap and low cost, and can be used as a large diameter valve.
Due to the influence of ambient temperature, the ball valve must have a seal that corresponds to the temperature and characteristics of the medium. In terms of sealing, the butterfly valve has a metal-to-metal seal, and also it has a low-temperature soft-sealed butterfly valve. Since the butterfly valve is opened and closed relatively quickly, but the flow of the butterfly valve is affected by the valve flap, all the flow resistance is relatively small compared to the ball valve, but butterfly valve switching speed can be faster than the ball valve, just because flap of butterfly valve is light and so on. The flow rate of the butterfly valve can be as large as about 5M/S. When the butterfly valve is used as a regulating valve, it is generally desirable to adjust the loss of the system. The butterfly valve can theoretically be installed in any direction, but it is not ideally pressed in the other direction, so it is generally used as a one-way valve, and the ball valve can be used in both directions.