Since its appearance, in order to meet the increasingly severe working conditions, the three eccentric disc valve itself has also experienced the process of self-improvement and continuous development. Even if the most basic zero leakage, theoretically three eccentric disc valve can be achieved, but actually depends on careful design and precise manufacturing. On the basis of absorbing and summarizing the advantages and disadvantages of three eccentric disc valves of other brands, has launched its own unique three eccentric disc valve with the following characteristics:
1. API specifications
As we all know, API609 has actually become an international specification for valves used in important industrial pipelines. It is designed and manufactured in strict accordance with the latest 1997 version of API 609. Whats more, the basic design is not limited to one specification of API, bs5155 ANSI B 16.34, ASME sec VIII and other major specifications, which ensures that it can be used in all industrial fields.
Double security structure
In strict accordance with the specification requirements of API609, in order to prevent the deformation of butterfly plate caused by the influence of fluid pressure and temperature, valve rod dislocation, sealing surface engagement, two independent thrust rings are respectively installed on the upper and lower sides of butterfly plate, so as to ensure the normal operation of the valve under any working condition;
At the same time, in order to prevent sudden accidents caused by valve stem damage and flying out caused by unknown reasons, two independent valve stem flying out prevention mechanisms are designed at the inside and outside of the lower end of the valve, which also ensures that the pressure level can reach 2500 pounds from the side.
Deadband free design
In the design process, the application problems in the field of regulation and control are specially considered, the sealing principle of three eccentric butterfly valve is fully utilized, so that when the valve is opened and closed, the butterfly plate does not scratch the valve seat, and the torque of the valve rod is directly transmitted to the sealing surface through the butterfly plate, that is to say, there is almost no friction between the butterfly plate and the valve seat, thus eliminating the common jumping phenomenon of opening the ordinary valve and eradicating it In the low opening range of the valve, the regulation failure caused by friction and other unstable factors means that the valve can enter the adjustable area from zero opening to 90 opening, its normal regulation ratio is more than twice that of the general butterfly valve, and the regulation ratio can be as high as 100:1. This creates a good condition for the use of the control valve, especially in the case of large caliber, the cost of the stop valve is extremely high, in addition, the stop valve can not achieve zero leakage, in the case of emergency shutdown, it is necessary to install a shut-off valve on the side of the stop valve, which integrates control and shutdown together, and its economic benefits are extremely considerable.
Body seat construction
There are two kinds of valve seat installation structures of triple eccentric butterfly valve. Most of them are installed on the butterfly plate for the convenience of drawing. The body seat structure is adopted and the valve seat is installed on the body. The utility model has the advantages that compared with the butterfly valve seat, the opportunity for the valve seat to contact the medium directly is greatly reduced, the degree of erosion of the valve seat is reduced, and the service life of the valve seat is prolonged.
The valve seat is composed of stainless steel sheet and graphite sheet. This kind of structure can effectively prevent the influence of small solid in the medium and the sealing surface occlusion caused by thermal expansion. Even if there is small damage, there will be no leakage, which is unimaginable for double eccentric butterfly valve or other three eccentric butterfly valve.
Replaceable seal pair The sealing pair of the butterfly plate is unique. Not only the body seat can be replaced, but also the sealing surface of the butterfly plate and the butterfly plate are independent, so the sealing surface of the butterfly plate can be replaced. That is to say, when the sealing surface of the butterfly plate is damaged, it is not necessary to send the butterfly plate back to the manufacturer or decompose the valve in a large scale, just replace the sealing surface of the butterfly plate, which not only greatly reduces the maintenance cost, but also greatly reduces the maintenance cost The maintenance man hours, maintenance intensity and difficulty are also discussed.
Balanced fixed structure
Starting from the shape characteristics of the sealing surface of the three eccentric butterfly valve, the fixing method of the sealing pair adopts the elliptical distribution of bolts, which not only makes the positioning accurate, but also makes each bolt evenly stressed, and eliminates the loosening and leakage of the sealing pair caused by the uneven stress distribution.
Application of triple eccentric butterfly valve
To sum up, triple eccentric butterfly valve, as the crystallization of the latest technology of valves, enhances the advantages of various valves and avoids the disadvantages of various valves, will be paid more and more attention by users and designers. The maximum pressure level can reach 2500 pounds, the standard caliber can reach 48 inches, and the length of clamp, lug, flange, ring joint, butt welding, jacket and various structures can be corresponding. Moreover, due to the wide choice of materials, high and low temperature and various corrosive media such as acid and alkali can also be corresponding freely. Especially in the aspect of large diameter, with its zero leakage advantage, on the shut-off valve, it is constantly replacing the coarse gate valve and ball valve, and also, with its excellent regulating function, on the regulating valve, it is constantly replacing the bulky stop valve. As a fact, up to now, it has been used in various important pipelines, such as oil and gas exploitation, offshore platform, oil refining, petrochemical, inorganic chemical, energy power generation and other industrial fields, including China.