What is a triple eccentric butterfly valve?

The triple eccentric butterfly valve is a kind of door type butterfly valve, which is opened and closed by rotating the valve stem. Its name comes from the triple eccentric points of the valve stem and valve disc: valve body eccentric, stem eccentric, seat eccentric, these three eccentric make the butterfly valve valve in the opening and closing of the formation of an eccentric track curve, the valve stem axis deviates from the center of the disc and the center of the body, and the valve seat axis and the valve body channel axis have a certain Angle, so as to achieve large flow adjustment and cut off.

What are the 3 eccentricities of triple eccentric butterfly valve ?

1. Valve body eccentricity: Valve body eccentricity refers to the difference between the geometric center of the valve body and the deflection axis of the valve disc. This eccentric distance is usually small, but it can reduce friction and wear between the valve and the pipe, and improve the sealing of the valve.

2. Stem eccentricity: stem eccentricity refers to the distance difference between the stem and the disc deflection axis. This eccentricity makes the valve open from one side first, forming a rotating curve track, which can reduce the impact force when the valve is opened instantaneously and extend the service life of the valve.

3. Valve seat eccentricity: Valve seat eccentricity refers to the difference between the geometric center of the valve seat and the deflection axis of the valve disc. This eccentricity can reduce the instantaneous pressure drop of fluid in the valve, reduce flow fluctuations and noise, and improve control accuracy.

Structure and working principle of triple eccentric butterfly valve

The triple eccentric butterfly valve is composed of a valve body, a valve shaft, a valve plate and a sealing part. The valve plate presents a triple eccentric shape, which can achieve forced scraping and self-cleaning, and has reliability under high temperature and high pressure.

The eccentric design of the triple eccentric butterfly valve makes there is almost no friction between the valve plate and the seat during the opening and closing process, which greatly improves the service life and sealing performance of the valve.

When the valve is closed, the disc makes contact with the seat, preventing fluid from passing through. triple eccentric structures on the disc allow the disc to automatically deviate from the seat during opening and closing, reducing friction and ensuring tightness. When the valve is open, the disc separates from the seat, allowing fluid to pass through.

The sealing surface of the triple eccentric butterfly valve is inclined cone structure, and the shape of the sealing surface of the valve plate is asymmetrical. The seal between the disc seal ring and the seat does not rely on the elastic deformation of the seat, but completely depends on the compression of the contact surface to achieve the seal. This structure effectively compensates the tolerance zone between the sleeve and the valve body and the elastic deformation of the valve stem under the medium pressure, and solves the sealing problem of the valve in the process of two-way interchangeable medium transportation.

Triple eccentric butterfly valve application field

1, chemical field: triple eccentric butterfly valve can be used in the chemical industry in the high temperature, high pressure fluid control, such as: oil refining, chemical fiber, fertilizer and other fields. Stability and efficiency make it a safe and reliable choice.

2, heating field: triple eccentric butterfly valve in the field of heating also has a wide range of applications. In the heating pipeline, the triple eccentric butterfly valve has the characteristics of compact, convenient and lightweight, easy to install and maintain, and can reduce the pressure drop of the pipeline to ensure the normal operation of the heating system.

3, the field of environmental protection: triple eccentric butterfly valves in the field of environmental protection also have many applications. For example, in the exhaust gas emission system, the triple eccentric butterfly valve can realize the adjustment of exhaust gas emissions by controlling the opening of the valve to ensure environmental protection requirements.

Triple eccentric butterfly valve features

The triple eccentric butterfly valve is a specially designed valve with the following characteristics:

1. Compact and light structure. The triple eccentric butterfly valve has the advantages of simple structure, small size, light weight and easy installation and maintenance.

2, good sealing performance. The triple eccentric butterfly valve adopts a special eccentric design, so that the sealing surface of the valve can achieve non-contact movement during the opening and closing process, thus improving the sealing performance.

3, high temperature and high pressure resistance. triple eccentric butterfly valve can withstand higher pressure, suitable for high temperature and high pressure occasions.

4, strong corrosion resistance. triple eccentric butterfly valves are usually made of stainless steel or other corrosion-resistant materials, suitable for handling acid, alkali, salt and other corrosive media.

5. Strong fluid control ability. The triple eccentric butterfly valve has excellent performance in fluid control and can achieve high flow and pressure control.

6, good adjustment performance. The degree of switching of the triple eccentric butterfly valve can be adjusted according to demand, which is suitable for a variety of industrial pipelines.

7, high security. The design of the triple eccentric butterfly valve adopts a double safety structure, such as the installation of independent thrust rings on the upper and lower sides of the butterfly plate to prevent the deformation of the butterfly plate and the dislocation of the valve stem, which increases the safety of use.

8, low torque operation. When the triple eccentric butterfly valve is operated, the torque of the valve stem is directly transmitted to the sealing surface through the butterfly plate, which makes the operation more convenient.

Advantages of triple eccentric butterfly valves

First, excellent sealing performance:

Due to the eccentric position of the stem of the triple eccentric butterfly valve, an additional lateral thrust is generated at the contact between the stem and the valve disc, which effectively improves the sealing performance. At the same time, the valve disc material is usually a composite structure of metal and polytetrafluoroethylene (PTFE), which can provide better corrosion resistance and wear resistance, ensuring a good sealing effect.

Second, low friction resistance:

The eccentric design allows only a small contact area at the contact point when the disc is in contact with the seat, thereby reducing the friction resistance when the disc is opened and closed and reducing the operating force.

Third, enhance high temperature resistance:

triple eccentric butterfly valve adopts metal disc, can withstand high temperature and high pressure working environment, suitable for high temperature fluid media control.

Four, quick opening and closing:

The triple eccentric butterfly valve has simple structure, small size, fast opening and closing speed, and can realize fast control.

5. Strong corrosion resistance:

The triple eccentric butterfly valve is made of metal material, which can adapt to the control requirements of corrosive media.

Disadvantages of triple eccentric butterfly valves

First, easy to wear:

The contact area between the butterfly plate and the sealing ring in the triple eccentric butterfly valve is small, so the butterfly plate often has to bear greater pressure, which is easy to lead to wear and reduce the sealing performance.

Second, easy to corrode:

The butterfly plate and valve body of the three-eccentric butterfly valve are usually made of cast steel, stainless steel and other materials, but it is easy to corrode in some special environments, affecting the service life.

Third, the vibration sound is large:

In the case of high flow, high pressure and high temperature, the butterfly plate of the triple eccentric butterfly valve is easy to produce self-excited vibration, emit large noise and vibration, affecting the working environment and equipment life.

In summary, the triple eccentric butterfly valve is a simple structure, the use of flexible fluid control equipment, widely used in chemical, heating, environmental protection and other fields. In the future development, the triple eccentric butterfly valve will continue to promote the development of fluid control technology, bringing more convenience to industrial production and people’s lives.