How Butterfly Check Valves Prevent Backflow of Media

How Butterfly Check Valves Prevent Backflow of Media

Jun 27, 2025 | News

The butterfly check valve is a common type of valve, mainly used to prevent the backflow of media in the pipeline system. Its working principle and design features make it very effective in many applications. The following are the main mechanisms of the butterfly check valve to prevent the backflow of media:

Butterfly Type Oblique Sealing Multifunctional Check Valve

1. Basic structure and core sealing mechanism

The butterfly check valve is mainly composed of valve body, valve disc, valve stem, sealing ring and other components. Its core sealing mechanism is based on the cooperation between the valve disc and the valve seat. The valve seat is usually made of elastic sealing materials such as rubber and fluoroplastics, or metal surfacing hard alloy. The valve disc rotates around a fixed axis in the valve body.

When the medium flows forward, the medium pressure pushes the valve disc to rotate around the axis and open, the valve disc is separated from the valve seat, and the medium passes smoothly. Once the medium stops flowing or flows back, the valve disc quickly rotates and fits tightly to the valve seat under the action of gravity, medium reverse pressure and possible spring auxiliary force.

2. Dynamic closing process based on fluid mechanics

Forward flow stage: The dynamic pressure generated by the flow of the medium acts on the surface of the valve disc, forming a torque that opens the valve disc. This torque needs to overcome the friction resistance torque of the valve disc rotation, the resistance torque generated by the spring preload, and the resistance torque generated by the valve disc’s own gravity. When the opening torque generated by the dynamic pressure of the medium is greater than the sum of the above resistance torques, the valve disc opens and the medium passes smoothly.

Closing transition stage: When the medium flow rate decreases, such as when the water pump stops or the system pressure fluctuates, the positive force of the medium on the valve disc decreases, and the direction of the resultant force on the valve disc begins to change. At this time, the valve disc begins to rotate in the closing direction under the combined action of its own gravity, the medium backflow pressure, and the spring force.

Fully closed stage: As the valve disc continues to rotate, it eventually fits tightly with the valve seat.

3. Special structural design enhances anti-backflow performance

Eccentric structure optimization:

Double eccentric design: The valve stem not only deviates from the center of the valve disc, but also deviates from the center line of the pipeline. This structure makes the valve disc completely separate from the valve seat at the moment of opening, further reducing friction; when closed, the valve disc gradually squeezes toward the valve seat to form a good sealing effect, which is especially suitable for high temperature and high pressure conditions.

Auxiliary seal and damping device:

Elastic seal ring: A seal ring made of nitrile rubber (NBR), ethylene propylene rubber (EPDM) and other materials, installed on the valve seat or valve disc. When the valve disc is closed, the seal ring is compressed, filling the tiny gap to form a secondary seal.

Damping device: Some butterfly check valves are equipped with dampers, such as hydraulic dampers, spring dampers, etc. During the closing process of the valve disc, the damper controls the rotation speed of the valve disc to avoid water hammer caused by closing too quickly.

Conclusion

Butterfly check valves achieve efficient and reliable prevention of medium backflow through the synergy of structural design, application of fluid mechanics principles, special structural optimization and other aspects, meeting the needs of different industrial fields and complex working conditions. FLUID TECH GROUP Valve, as a Chinese non return valve manufacturer and supplier, is committed to producing high-quality check valves, such as high performance butterfly valves. If you have any questions, please feel free to contact us!

What Media Are Suitable for Check Valves?

What Media Are Suitable for Check Valves?

May 30, 2025 | News

Check valves, also referred to as non return valves, are the key players of numerous fluid systems, as they permit the flow of the fluid in one direction and block its backflow. A sound understanding of what kind of medias are compatible with check valves is necessary in order to make sure that the equipment works properly and lasts long. In this article, we shall discuss various media that one can easily control using the check valve.

Understanding Check Valves

Check valves are the ones, which regulate single-direction flow in transport systems. They resist backflow, the consequences of which could be system damage, contamination, and inefficiencies. Besides, these valves are popularly used in such spheres as water treatment, oil, and gas, and in the HVAC sector.

Types of Check Valves

Swing Check Valves: When working with lower flow rates, these valves are the best choice as they use a swinging disc to regulate the flow.

Ball Check Valves: Herein, a ball rolls inside the valve body, leaving no space for the backflow to happen, hence achieving the task of sealing reliably and not allowing any return of the fluid.

Wafer Check Valves: Easy to install and with very low weight, wafer check valves are indeed the best choice for applications where the space is critical.

Suitable Media for Check Valves

1. Water

Water is one of the media, that is being used most often with check valves. Whether in municipal water supply systems, irrigation, or industrial processes, check valves assure that water flows in the direction intended. Stainless steel check valves are very good at their job in water locations, due to their resistance to corrosion and their very nature of durability.

2. Oil

The oil and gas industry uses check valves to counter the potentially damaging effects of backflow in pipelines. FLUID TECH GROUP has some stainless steel check valves of high quality that can handle the different kinds of oil, such as crude oil and refined products, applicable in multiple areas.

3. Gas

Gas pipes are used to control the gas flow and thus avoid gas flowing back in the system. The stainless steel check valves are one ultimate option for sealing capabilities; they can be used in high-pressure gas applications.

4. Chemicals

One of the commonly used check valves is found in the industries managing the flow of chemicals. Check valves installed in chemical plants or sewage plants ensure that the backflow and thus the infectious substances do not reach there from the next process. Corrosion-resistant materials like stainless steel and the well-chosen sealing materials such as EPDM and PTFE are the basis for this broad applicability in resistance to various media like chemicals.

5. Slurries

In sectors like mining and wastewater treatment, check valves still play a crucial role in the handling of slurries—solid-and-liquid blends. Such cases require the use of solid valves that can bear the brunt of harmful materials and still work well. FLUID TECH GROUP’s swing check valves and ball check valves are the optimal choices for slurry applications, providing consistent performance even under extreme conditions.

Conclusion

Choosing the right check valve for your application is essential for ensuring efficient fluid management. Understanding the suitable media for check valves, including water, oil, gas, chemicals, and slurries, helps you make informed decisions. FLUID TECH GROUP Valve, as a leading China valve manufacturer, offers a range of high-quality stainless steel check valves and flow control valves designed to meet the demands of various industries.

If you’re looking for reliable and durable check valves, consider FLUID TECH GROUP Valve’s extensive product line. With over 60 years of experience in valve manufacturing, we are committed to providing solutions that enhance operational efficiency and safety. Contact us today for more information about our check valves and how they can benefit your applications.