At present, butterfly valves, as parts that control flow and pipe system, have been widely used in petroleum, chemical engineering, metallurgy, hydroelectricity, and other fields. Hermetic seal is the most-used known technique of butterfly valve seals, whose materials include rubber, PTFE, etc. But it is not suitable for processes that require corrosive, abrasive media, high temperature and pressure due to the restriction of its structure. Recently, there is a more advanced type of butterfly valves named triple offset metal-seated butterfly valve that uses high and cryogenic temperature resistant valve seat and body as the jointing components. Multilayer seal is fixed on the valve plate. Compared to traditional butterfly valves, this kind is better in high temperature resistance, operation, sealability, and life span, with no rubbing at startup and an increase of torque to compensate losing sealability at shutdown.
Yet, there are still problems existing during the process of using.
1. Sealability will be directly affected after the interlayer between pieces of sheet metal is frontally washed by the medium when the valve plate is open, since multilayer seal is fixed on the valve plate.
2. The flow coefficient of the thick valve plate is so big that it is not fit to valves under DN 200.
3.The principle of triple offset butterfly valve structure is that the seal between the surface of valve plate and valve seat hinges on the transmission gear. In co-current state, the sealability of the valve grows with the pressure brought by the medium. Whereas in counter-current state, as the medium’s pressure increases and becomes higher than that between the valve plate and seat, the seal starts leaking.
3.The principle of triple offset butterfly valve structure is that the seal between the surface of valve plate and valve seat hinges on the transmission gear. In co-current state, the sealability of the valve grows with the pressure brought by the medium. Whereas in counter-current state, as the medium’s pressure increases and becomes higher than that between the valve plate and seat, the seal starts leaking.
This utility model is aiming for a universal, high-performance bi-directional triple offset metal-seated butterfly valve with zero leakage, high sensitivity, long life span, high temperature resistance, anti-corrosion, superior abrasion resistance.
Its features are as follow:
The seal of the valve seat is composed of multilayer stainless sheetsteel on both sides of the flexible T-seal. This brings advantages of hard seal and soft seal. Also, high sealability will maintain no matter in cryogenic temperature or high temperature;
The sealing surface of valve plate and seat is oblique cone structure and welded with high temperature corrosion resistant alloy. And on co-current state, when the pressure from medium increases, the tighter between the oblique cone surface and the sealing surface of valve plate, the better the sealability is;
Springs fixed in the middle of the pressure plates assemble with adjustable bolts, which automatically and effectively make up for the tolerance zone between axle sleeve and valve body, as well as the elastic deformation caused by the pressure from mediums, thus it solves the problem of unstable sealability.
This utility model is capable of replacing gate valve, globe valve and ball valve because it is not like any other existed techniques that have to install both hard and soft multilayer seals, but rather, it cancels the step, while adding adjustable ring between the pressure plate and the valve seat, which is an ideal bidirectional hard sealing method.
Its features are as follow:
The seal of the valve seat is composed of multilayer stainless sheetsteel on both sides of the flexible T-seal. This brings advantages of hard seal and soft seal. Also, high sealability will maintain no matter in cryogenic temperature or high temperature;
The sealing surface of valve plate and seat is oblique cone structure and welded with high temperature corrosion resistant alloy. And on co-current state, when the pressure from medium increases, the tighter between the oblique cone surface and the sealing surface of valve plate, the better the sealability is;
Springs fixed in the middle of the pressure plates assemble with adjustable bolts, which automatically and effectively make up for the tolerance zone between axle sleeve and valve body, as well as the elastic deformation caused by the pressure from mediums, thus it solves the problem of unstable sealability.
This utility model is capable of replacing gate valve, globe valve and ball valve because it is not like any other existed techniques that have to install both hard and soft multilayer seals, but rather, it cancels the step, while adding adjustable ring between the pressure plate and the valve seat, which is an ideal bidirectional hard sealing method.
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