Difference between wafer type butterfly valve and flange type butterfly valve-Belo Valve

Butterfly valve is one kind of widely used industrial valve, which is used in various pipelines to open, close and regulate the flow. According to sealing material, butterfly valve can be divided into metal hard sealing butterfly valve and soft sealing butterfly valve. According to end connection, butterfly valve can be divided into wafer type butterfly valve and flange type butterfly valve. According to structure forms, butterfly valve can be divided into concentric butterfly valve, single eccentric butterfly valve, double eccentric butterfly valve, triple eccentric butterfly valve. 

Belo Valve is a more than 15 years professional manufacturer for industrial valves, like butterfly valves( center line wafer butterfly valve, manual butterfly valve, lever driving butterfly valve, butterfly valve with worm gear box, lug type butterfly valve, soft seal butterfly valves, hard seal butterfly valves, flange butterfly valves, ductile cast iron butterfly valves, stainless steel butterfly valve), gate valves(including DINF4 gate valves, DINF5 gate valves, DIN3352 gate valves, rising stem gate valves, non rising stem gate valves, soft seal gate valves, hard seal gate valves, hydraulic gate valves, sluice valves), globe valves( DIN globe valves, bellows globe valves, electric globe valve), ball valves( welded ball valves, soft seal ball valves, stainless steel ball valves, WCB ball valves, ductile cast iron ball valves, API ball valves), check valves( wafer type check valves, swing check valves, rubber disc check valves, ball type check valve, foot valve/bottom valve), fire protection valves( grooved butterfly valves, grooved gate valves, grooved strainers, grooved check valves), hydraulic control valves,etc.today we are going to talk about the difference between wafer type butterfly valve and flange type butterfly valve: 

The difference between the wafer type butterfly valve and the flanged type butterfly valve is mainly reflected in the definition, structure, characteristics,etc. In terms of characteristics, the outer shape of the disc of the flange butterfly valve adopts a spherical shape, which prolongs the service life of the flange butterfly valve. The thickness of the disc of the wafer type butterfly valve is the only resistance for the medium to flow through the butterfly valve body, and the pressure drop through the wafer type butterfly valve is very small. The common models of wafer type butterfly valves are: D71X/F, D371X/F,D373H, D373Y, D373W,etc. 

1. the difference between wafer butterfly valve and flange type butterfly valve in definition: 

1.1. flange butterfly valve: when the flange type butterfly valve is in the fully open position, the thickness of the disc is the only resistance for the medium flowing through the valve body, so the pressure drop generated by the flange type butterfly valve is very small. So it has better flow control characteristics. 

1.2. wafer type butterfly valve: wafer type butterfly valve is installed in the diameter direction of the pipeline. In the cylindrical channel of the butterfly valve body, the disc-shaped plate rotates around the axis, and the rotation angle is between 0°-90°, when the disc rotates to 90°, the wafer type butterfly valve is in fully open position; 

2. the structural difference between wafer type butterfly valve and flange type butterfly valve: 

2.1. flange type butterfly valve: flange type butterfly valve refers to a butterfly valve whose has two flanges at its two connection ends. When installing, flange butterfly valve only needs to correspond the flanges holes on the flanged butterfly valve with the flanges holes on the pipeline one by one, and then connect them in series with bolts and nuts. 

Flanged butterfly valves are more suitable for large diameter valves. As the diameter increases, the number of the flange holes of the flange type butterfly valve will also increase correspondingly, and the stability of flange butterfly valve is better when connecting with pipelines. In addition, under the conditions of the same diameter and the same material, the weight and volume of flange type butterfly valve are lighter and smaller than other types of industrial valves, such as gate valves, ball valves,etc. So on large diameter pipelines, flange butterfly valves can be used instead of gate valve,ball valve, and other industrial valves. 

The sealing structure of the flange type butterfly valve adopts PTFE and synthetic rubber to form a composite valve seat. The resilience of the butterfly valve is provided by synthetic rubber, and the friction coefficient of the PTFE is low, it is not easy to wear and to age, which makes the service life of the flange type butterfly valve longer. 

2.2. wafer type butterfly valve: the structure of wafer butterfly valve is different from the flange type butterfly valve, wafer type butterfly valve does not have that two end connect flanges on its valve body like the flange type butterfly valve does. The common wafer type butterfly valve has only four bolt holes on its valve body. When installing on the pipeline, it is necessary to use two flanges to clamp the wafer butterfly valve in the middle, and then use the bolts to pierce through the flange hole, then the bolt holes on the valve body of the wafer butterfly valve, then connect with the holes on the pipelines. The face to face length of wafer type butterfly valve is shorter, and the volume of wafer butterfly valve is smaller, and the weight of wafer butterfly valve is lighter. Among the small diameter valves, the wafer type butterfly valve has more advantages than the flange type butterfly valve, and the cost of the wafer butterfly valve is lower than flange butterfly valve. 

There are two types of sealing forms in butterfly valves. One is resilient sealing, and the other metal sealing, for the resilient seated butterfly valves, its sealing ring can be fixed on the valve body or on the valve disc. 

According to driving methods, wafer type butterfly valve can be divided into lever handle wafer type butterfly valve, worm gear wafer type butterfly valve, electrical wafer butterfly valve, pneumatic wafer type butterfly valve. According to the difference of the sealing material, wafer type butterfly valve can be divided into metal hard sealing wafer butterfly valve and rubber-lined soft sealing butterfly valve or PTFE lined soft sealing wafer butterfly valve. 

The common Model No for wafer type butterfly valve are: D71X/F, D371X/F, D373H, D373W, D671X/F, D971X/F, D673H, D973H, etc. 

But for wafer type butterfly valve and flange butterfly valves, they also have some in common, for example, they both have soft sealing material and hard sealing material: (soft sealing wafer butterfly valve, metal hard sealing wafer butterfly valve. Soft sealing flange butterfly valve and metal hard sealing flange butterfly valve). hard sealing material is suitable for pipeline with high temperature and high pressure, otherwise, soft sealing material is suitable for pipeline with normal temperature and low pressure.