Types of blind flange

The function of blind flange is to cut off the medium in the pipeline, which can be divided into the following types according to the use pressure and the form of sealing surface:

ANSI B16.5 ASTM A182 F304 blind flange

1.Smooth face blind flange is used with smooth sealing face flange, and its applicable pressure range is 1.0~2.5MPa.

2.The convex blind flagne has a convex surface on one side and a concave surface on the other side, which is used together with the concave and convex sealing surface flange. The operating pressure is 4.0MPa, and the specification range is DN25~400mm.

3.The trapezoidal groove surface blind flange is used in conjunction with the trapezoidal groove sealing surface flange, and the operating pressure range is 6.4~16.0MPa. The specification range is DN25~300mm.

4.The “8” type blind flange is also divided into three types: smooth surface, concave convex surface and trapezoidal groove surface. The use pressure is the same as the above three types of blind flanges. The difference between the “8” type blind flange is that it combines the two uses on one component, that is, it connects and fixes the blind flange and gasket together. When the blind flange is padded in the flange, the gasket exposed outside is used as a visual sign of whether the pipe is cut off.

Stainless steel SS316 spectacle blind flange

There are many kinds of manufacturing materials for the “8” type blind flange, which can be selected according to the temperature and pressure of the medium conveyed. Generally, when the temperature of low pressure pipeline is not more than 450 ℃, the materials used include Q235A, 20 # steel and 25 # steel; When the temperature is 450~550 ℃, the materials used include 15CrMo and 1Cr5Mo. When the pressure is 4.0~16.0MPa and the temperature is greater than 550 ℃, stainless steel shall be used.

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