Flat Face vs. Raised Face Pipe Flange

In industrial production and fluid pipeline connection, flat face pipe flange and raised face pipe flange are two common flange connection forms.

The sealing surface and flange surface of the flat face pipe flange are flat, and the connection between the sealing surface and the flange surface is achieved by tightening with screws, and the sealing gasket or filler is compressed on the two flat surfaces.

The sealing surface and flange surface of the raised face pipe flange are arc-shaped, and the sealing surface and the flange surface are connected with screws, and the sealing ring or filler is compressed along the arc surface to achieve sealing.

Similarities between flat face pipe flange and raised face pipe flange

Flat face pipe flange and raised face pipe flange have common characteristics in basic functions and connection principles. They are both used for the connection of pipelines or equipment to achieve sealed transmission of fluids. In terms of connection methods, they are fixed and sealed by bolts and gaskets. The materials are also similar, usually using general materials such as carbon steel and stainless steel, and are selected according to working conditions. So what are the differences between them?

Differences between flat face pipe flange and raised face pipe flange

1. Different sealing methods

The sealing method of flat face pipe flange is relatively simple, using sealing gaskets or packings to seal on the flat surface, while raised face pipe flanges use arc-shaped sealing rings or packings to seal on the raised surface, and the sealing performance is better.

2. Different fastening methods

The fastening methods of flat face pipe flange and raised face pipe flange are also different. Flat face pipe flanges need to use bolts to fasten the flange and valve together, while raised face pipe flanges also need to use bolts for fastening, but due to the use of sealing rings, the fastening force needs to be stronger than that of flat face pipe flanges.

3. Different manufacturing costs

Because raised face pipe flanges need to use sealing rings or packings and use higher precision processing, their manufacturing cost is higher, while flat face pipe flanges only need to cover the flat surface with sealing gaskets or packings, and the manufacturing cost is relatively low.

4. Different usage scenarios

Flat face pipe flanges are often used for some low-pressure and non-high-sealing pipeline connections because of their simple sealing methods and low costs. The raised face pipe flange has better sealing performance and is usually used in some occasions with high sealing requirements, such as: connection of high-pressure containers, oil and gas pipelines, chemical pipelines, etc.

5. Different installation and maintenance

The flat face pipe flange is easy to install, but it has high requirements for the flatness and cleanliness of the flange surface. It is necessary to ensure that the gasket is evenly stressed during installation. The raised face pipe flange needs to be matched with the concave flange during installation, which has good centering, but the flange may need to be disassembled when replacing the gasket, and the maintenance cost is high.

Conclusion

In general, flat face pipe flanges and raised face pipe flanges have different usage scenarios. When choosing, users can consider the sealing, fastening method and manufacturing cost according to actual needs. If you have any questions, you must consult professional or flange supplier to avoid unnecessary losses.