Understanding Butterfly Valve Seats: The Differences Between Hard, Soft and Rubber Lined

June 06, 2024
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Among many industrial valves, wafer style butterfly valves are known for their unique design and efficient fluid control capabilities named for tis lamellar design, this valve consists of a dis fixed on a rotating axis that rotates to completely block the passage when the valve is closed.

When selecting a wafer style butterfly valve, factors such as fluid type, pressure range, temperature range and flange standard should be considered. in addition, the selection of disc and seat materials should also be determined based on the application and fluid medium.

Whether in a new build project or as an upgrade to an existing system, this butterfly valve provides reliable performance and an economical solution.

In the selection of wafer butterfly valves, we often consider hard rubber seat, soft back and rubber lining. The biggest difference between the three is the installation method of the valve body and sealing material, which is specifically reflected in the different structural design of the valve body and the shape of the valve seat.

First, let's take the DN100 valve body as an example，Intuitive observation of the difference in valve bodies.

What is the difference between butterfly valve seats?

First of all, what is a valve seat? The valve seat is a removable part inside the valve, used to support the fully closed position of the valve plate and form a sealing ring. Generally, the valve seat diameter is the maximum flow diameter of the valve.

The valve seat material of the butterfly valve is very wide, and all kinds of rubber and metal materials can be used as valve seat materials;

eg:EPDM, NBR，PTFE, VITON, STELLITE，etc

Rubber Hard back seat

The material of the hard back seat is composed of rubber on the outside wrapped on the hard back inside. The installation method is to use a professional valve assembly platform to press the valve seat into the valve body through a machine. This butterfly valve is the most common butterfly valve with high cost performance.

Rubber Soft back valve seat

The material is made of rubber only, so it is highly elastic and is also called a backless valve seat. Its installation method is also more convenient for workers to repair, replace and disassemble later. This butterfly valve has the advantages of easy replace the valves parts. Hot sell in EU/US market.

Rubber-lined (Vulcanized) butterfly valve

The rubber-lined seat of the rubber-lined butterfly valve is hung on the valve body as a whole and becomes one with the valve body. It is produced in batches by large-scale equipment. Compared with traditional butterfly valves, this butterfly valve has the advantages of high temperature resistance, easy operation, no friction when opening and closing, good sealing performance and long service life. The only downside is the seat part cannot be replaced.

Display of butterfly valve finished products

Below is a demonstration of the appearance of different valve seats installed on the butterfly valve body (the pictures are all real product photos).

Concluding Remarks

In summary, each type of butterfly valve seat (hard, soft and rubber lined) has its own unique advantages and applications. Choosing the right valve seat can effectively improve the performance and service life of the system. Union Valve is a professional butterfly valve supplier, providing butterfly valves of various types and specifications.If you want to know more, please contact us as soon as possible

About the Author

Serena Zhang

Tianjin Union Valve Co., Ltd Sales Manager

With 4 years of rich valve export experience and high-quality service, your order will be worry-free. Prompt reply 24 hours a day, 7 days a week. Welcome your inquiries!

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Butterfly Valve Seats