News Center

What is the difference between butterfly valves with and without pins?

       1.Structure of pinned butterfly valve

Pinned butterfly valves utilize a pin connection between the valve stem and the butterfly plate. The pins are usually made of high-strength metals, such as stainless steel and alloy steel, to ensure that they can withstand high shear and torque during frequent opening and closing.

The pins go through the pre-processed pin holes on the valve stem and butterfly plate, and are fixed by nuts or other locking devices, and this connection allows the butterfly plate to be firmly installed on the valve stem. When the valve stem rotates, the butterfly plate can accurately follow the movement of the stem to realize the opening and closing operation of the valve.

In addition to the pin connection, the pinned butterfly valve is also equipped with components such as valve seat, valve body, and seals. The valve seat is usually installed inside the valve body, which cooperates with the butterfly plate and plays the role of sealing.

The seal is installed between the butterfly plate and the valve seat to further improve the sealing performance of the valve. The body structure of the pinned butterfly valve is more complicated and requires precise machining of the pin holes and other parts to ensure the accuracy of the fit between the various parts.

       2.Structure of pinless butterfly valve

Pinless butterfly valve abandons the traditional pin connection and adopts ferrule, slot or other fastening methods to realize the connection between valve stem and butterfly plate. Take the ferrule connection as an example, the end of the valve stem is designed with a special shaped ferrule, and the corresponding position on the butterfly plate is processed with a slot.

When installing, insert the ferrule into the slot, tighten the nut or other ways to make the ferrule and the slot close fit, so as to realize the connection between the valve stem and the butterfly plate. This connection reduces the pin as a component and simplifies the structure of the valve.

Pinless butterfly valves also have basic parts such as valve seat, valve body and seals. Since there is no need for pin connection, the structure of the body of pinless butterfly valve is relatively simple, which reduces the complex process of processing pin holes and so on, and lowers the manufacturing cost.

In addition, the pinless butterfly valve pays more attention to the overall structural strength and stability in the design, and ensures that the valve can operate reliably in the working process by optimizing the connection between the valve stem and butterfly plate.

       3.Impact of structural design differences

The pinned connection of the pinned butterfly valve makes it relatively easy to install and remove the butterfly plate, and when repairing or replacing the plate, only the pin needs to be removed. However, the pin, as an independent component, carries the risk of wear and loosening and requires regular inspection and maintenance.

In comparison, pinless butterfly valves have a more compact connection structure, which reduces the possibility of failure due to loose parts and improves the reliability of the valve. However, when it comes to repairing and replacing the butterfly plate, pinless butterfly valves are relatively complicated to operate and require special tools and techniques.

        4.Impact of differences in sealing performance

In general working conditions, the sealing performance of pinned butterfly valves and pinless butterfly valves can meet the requirements of use. But in some special working conditions, such as high temperature, high pressure, strong corrosion and other environments, the sealing performance of the pinned butterfly valve may be affected by the thermal expansion of the pin, corrosion and other factors, resulting in a decline in sealing performance.

The pinless butterfly valve, due to its simple structure and the absence of pin-related problems, has relatively more stable sealing performance under special working conditions. However, for some occasions that require very high sealing accuracy, the precise positioning function of pinned butterfly valves may be more advantageous.

        5.Impact of differences in liquidity

In the media is relatively clean, the flow requirements are not high occasions, pinned butterfly valve and pinless butterfly valve flow capacity difference on the system operation has less impact.

However, the advantages of pinless butterfly valves are more obvious when dealing with media containing a large number of impurities or particles, as well as occasions with higher flow requirements.

Pinless butterfly valves can effectively reduce system failures due to valve clogging and improve system operating efficiency.

        6.Impact of maintenance variances

The maintenance of pinned butterfly valves is demanding, requiring specialized technicians and tools, and the maintenance cost is relatively high. If the maintenance is not appropriate, it is easy to lead to valve failure, affecting the normal operation of the system.

The maintenance of pinless butterfly valves is relatively simple, reducing the technical requirements for maintenance personnel, reducing maintenance costs and downtime, and improving the reliability and stability of the system.