1 Design of three-eccentric butterfly valve

The design books available on the market for three-eccentric butterfly valves contain rather outdated designs, and detailed design drawings need to be tailored to specific manufacturing processes. Are you planning to use a multi-layer structure or a fully metal construction?

This post was last edited by Xianjian Qiyuan2015 on 2020-6-7 at 16:17. 1

Currently, the domestic market is focusing on all-metal designs. All-metal designs require stricter standards compared to multi-layer designs; the eccentricity parameter is very important. If the multi-layer design approach is used, the success rate is low. However, all-metal components are more expensive. Do you plan to harden the all-metal sealing surfaces?

Yes, the sealing surface is to be surfaced with cemented carbide. Right now, I lack experience in determining the eccentricity distance and angle; following the design manual exactly, I’m not sure what the results will be

The design manual will not provide you with the eccentricity parameters; these vary from one manufacturer to another. They are generally determined based on the manufacturer’s own existing angles for processing inclined molds. The design of eccentricity parameters is a core technical aspect – in the case of all-metal components, it is essential to ensure that there is no interference even in the presence of processing and assembly errors; otherwise, sealing will fail. Once this issue is resolved, the rest becomes much easier to handle, as the other processing steps are simple. If both sealing surfaces are to be clad, it will be a bit more complicated; when cladding Stellite, the deformation of the ring components is quite severe. Do you grind your sealing surfaces? What level of surface finish should be prepared? If the sealing effect is not above 0.8, it won’t be very good. By the way, is your factory in Zhejiang or Jiangsu?

After precision turning of the surfacing layer, it is ground, with a roughness level estimated to be around 0.8–1.6. We are a company based in Wuhan, Hubei

Where is the factory in Hubei? Wuhan? High-temperature or low-temperature? Bro

Wuhan East Lake High-Tech Zone: hard-sealed design, mainly for high-temperature operating conditions

At present, the manufacturers of triple eccentric components in China are more or less similar; each one has a different eccentricity angle, and this angle can be measured using actual products. The first tier can achieve positive pressure suppression in compliance with API598 standards, and negative pressure suppression up to a leakage rate of 2.0 MPa class VI. Those in the second tier are still struggling to reach V level, let alone cope with high- or low-temperature conditions. German OHL valves belong to the 4-eccentric type. Currently, both forward and reverse API 598 leakage standards can be achieved. Pressure difference 4.0 mpa