Triple offset butterfly valve features:
The triple eccentricity refers to the addition of an angular eccentricity on the basis of the double eccentric structure, say, the sealing surface of the butterfly valve is inclined and tapered. Triple eccentric butterfly valve is also called triple offset butterfly valve. We can produce two types, one is triple eccentric multi-layer sealing butterfly valve, and the other is triple eccentric all-metal sealing butterfly valve.
The triple eccentric multi-layer sealing butterfly valve is accomplished by the elasticity of the sealing ring on the valve plate, and the elasticity of the sealing ring is produced by its radial compression and flexibility. The contact surface between the sealing ring and the valve seat is an oblique cone. The contact angle between the sealing ring and the valve seat produces a slight “wedge effect” to make the sealing ring flexible and radially compressed. It is precisely because of the uniform contact between the valve seat and the sealing ring and the flexibility of the sealing ring that the load on the valve seat is even, so that the tightest cut-off can be achieved with the smallest torque. The elasticity generated by the torque makes the valve close tightly, regardless of the flow direction of the medium or the force of the medium.
Structural features of triple eccentric multi-layer sealing butterfly valve:
Double safety structure
No dead zone design
Replaceable sealing pair
Fix the structure evenly.
The characteristic of the triple eccentric hard-to-hard structure is that the outer periphery of the butterfly plate is processed into an outer inclined cone, and the inner side of the sealing valve seat is processed into an inner inclined cone. At this time, the sealing section of the butterfly valve becomes an oval. The shape of the sealing surface of the butterfly plate is therefore asymmetric from top to bottom.
Because the sealing surface is oblique cone shape, the larger side of the disc separated by the stem shaft presses upwards to the valve seat along the large inclined curved surface, and the smaller side discs presses down to the valve along the small inclined curved surface seat. The seal between the butterfly plate sealing ring and the valve seat does not rely on the elastic deformation of the valve seat, but completely relies on the compression of the contact surface to achieve sealing. Therefore, the opening and closing of the triple eccentric butterfly valve is basically friction-less, and as the closing pressure increases, the valve is closed tighter. From the structure principle of the triple eccentric butterfly valve, it is not difficult to see that the triple eccentric full metal sealing butterfly valve has the following advantages:
All-metal sealing design, the sealing surface adopts STL /Stellite alloy surfacing technology, which solves the problem of poor sealing performance of butterfly valves under severe working conditions such as high temperature, high pressure and low temperature.
The new three-eccentric structure design realizes zero friction. The performance is more stable. Sealed service life is extended. Through optimized design, the flexible opening and closing of the butterfly valve from low temperature to high temperature is ensured, which fully meets the sealing standard of zero leakage of the valve under severe working conditions.
The main features of the triple offset all-metal butterfly valve:
Both flow directions can bear pressure, realizing installation without flow direction restriction
Replaceable valve seat and seal ring design will not cause the whole machine to be scrapped due to seal wear problems, thereby reducing the cost of use;
The difference between the all-metal sealing structure butterfly valve and the multi-layer sealing butterfly valve is that the conventional multi-layer metal sealing structure is laminated with metal sheets and graphite, and the multi-layer sealing surface is susceptible to fluid erosion and has a short service life. The triple eccentric all-metal butterfly valve sealing pair adopts all-metal forged sealing ring and surfacing stellite alloy on the sealing surface. Its advantages are erosion resistance, long life-time, wear resistance, and can be applied to various high temperatures, high pressure harsh conditions.
Related types of butterfly valves:
We have other types of butterfly valves: wafer butterfly vlave, Lug type butterfly valve, U flange butterfly valve, double flange butterfly valve, fluorine lined PTFE butterfly valve, and double eccentric butterfly valve used in Marine industry, Water supply and drainage, fire fighting, shipbuilding, water treatment and other systems, with Nominal Diameter of DN50 to DN1200, NBR/EPDM/VITON, Certificates & Approvals: DNV-GL, Lloyds, DNV, BV, API, ABS, CCS. Standards: EN 593, API609, API6D