A tube sheet flange is a special flange structure that integrates the tube sheet and flange, mainly used for connecting the tube bundle and shell in heat exchangers, pressure vessels, and other equipment. It has the dual functions of supporting the tube bundle and sealing the medium. Its core feature is the integrated design of the tube sheet and flange, which achieves pressure isolation and tube bundle fixation between the tube side and the shell side. The following is an introduction from the aspects of structure, performance, and application:

Structural Design and Working Principle

Core Components

Tube Sheet Body:

The thickness is usually 10-100mm (determined according to the equipment pressure and pipe diameter), and the material is mostly Q345R, 16MnDR (low temperature), 304/316L (corrosion resistance);

Tube holes are opened on the surface (arranged in a triangle/square), and expansion grooves or sealing grooves can be processed in the holes, used to fix the heat exchange tubes (such as expansion, welding, or expansion welding).

Flange Ring:

Welded or integrally forged at the edge of the tube sheet to form a sealing pressing surface. Common forms are flat (FF), concave-convex surface (MFM), and ring groove surface (RJ) for high-pressure scenarios;

Bolt holes are opened on the flange ring, and connected to the shell flange through bolts to achieve equipment sealing.

Extension Structure (Optional):

Neck tube sheet flange: A conical neck (similar to a neck welding flange) extends from the edge of the tube sheet, improving fatigue resistance and suitable for high-pressure conditions (PN≥40);

Lined tube sheet: The surface of the tube sheet is overlay welded with a corrosion-resistant layer (such as Inconel 625), used for strong corrosive media (such as concentrated nitric acid, hydrofluoric acid).

Working Principle

As a core component of the heat exchanger, the tube sheet connects the tube bundle (tube side) on one side and the shell (shell side) through the flange ring and bolts on the other side;

The medium pressure is transmitted to the bolts through the flange ring, relying on the sealing gasket (such as metal wound gasket, octagonal gasket) to achieve isolation between the tube side and the shell side, and the tube sheet supports the tube bundle to resist fluid vibration.

Core Product Features

1. Mechanical Properties and Structural Advantages

High-strength support: The tube sheet thickness is calculated according to GB/T 151 "Heat Exchanger", which can withstand the pressure difference between the tube side and the shell side (ΔP≥10MPa), such as the condition of 16MPa tube side pressure and 6MPa shell side pressure in high-pressure condensers;

Resistance to temperature difference stress: The integrated design of the tube sheet and flange can buffer the temperature difference deformation between the tube bundle and the shell (such as when the temperature difference of the steam heat exchanger is ≥80℃), reducing the risk of tube sheet cracking.

2. Sealing and Corrosion Resistance

Multiple sealing designs:

Connection between tube sheet and heat exchange tube: Strength welding + expansion process is used (leakage rate <0.1%);

Flange sealing surface: Metal ring gasket is used in high-pressure scenarios, sealing pressure ≥60MPa, suitable for toxic, flammable and explosive media (such as liquefied petroleum gas heat exchangers).

Flexible material matching:

Coal chemical heat exchanger: Tube sheet uses 15CrMoR (resistant to high-temperature hydrogen corrosion) + flange ring uses Q345R;

Seawater desalination equipment: Tube sheet overlay welds 6% Mo stainless steel (N08367), flange ring uses 316L, resistant to chloride ion corrosion (Cl- concentration ≥20000ppm).

3. Installation and Maintenance Convenience

Modular installation: The tube sheet flange can be installed as a whole and connected to the shell flange with bolts. Compared with on-site welding, the efficiency is increased by 30% (such as the installation of large tube heat exchangers);

Maintainability: The tube bundle can be removed and cleaned after removing the bolts, and the surface of the tube sheet can be mechanically polished (roughness Ra≤1.6μm), reducing the risk of scaling.

4. Cost and Customization Advantages

Material optimization: The tube sheet and flange ring can use different materials (such as stainless steel for the tube sheet + carbon steel for the flange ring), reducing the cost by 25%-40% compared to the overall stainless steel flange;

Non-standard customization: Non-standard tube sheets (such as elliptical and annular tube sheets) can be designed according to GB/T 151 and ASME VIII Div.1 to adapt to special equipment structures.

Comparison with Other Flange Types

Application fields

Wind power industry	Shipbuilding	Mechanical manufacturing
Nuclear power industry	Oilfield industry	Chemical industry