Why does a flange leak? What are the common reasons?

- Mar 28, 2018-

Analysis of seven common causes of leaking flanges:


The flange connection, to be exact, should be a bolt, flange, gasket connection, and the sealing is accomplished by the synergistic effect of the three. The gasket is the core component that completes the seal. Below, the Chongqing flange manufacturer takes you to know the common seven causes of flange leakage.
Mouth


Biased refers to the fact that the pipe and flange are not straight and dissimilar, and the flange faces are not parallel. When the pressure of the internal medium exceeds the load pressure of the gasket, flange leakage will occur. This condition is mainly formed in the process of installation, construction or maintenance and is easier to find. As long as you carefully examine the project when it is completed, you can avoid the onset of such accidents.


2. Wrong mouth
The wrong mouth means that the pipe and the flange are straight, but the two flanges are different. Flanges do not have the same mind, and the bolts that form the surrounding are not free to wear bolt holes. In the absence of other methods, as long as the hole or the smaller one bolt hole through the bolt hole, and this method will reduce the tension of the two flanges. Also, there is an error in the sealing surface of the sealing surface, which is very prone to leakage.


3. Open mouth
Open mouth, refers to the flange gap is too large. When the flange clearance is too large to form an external load, such as axial or tortuous load, the gasket will be subjected to shock or vibration, lose the pressing force, and then gradually lose the sealing kinetic energy and cause failure.
Wrong hole


4.The wrong hole means that the pipe is concentric with the flange, but the distance between the two bolt holes is relatively large. The wrong hole will cause the bolt to produce stress, and the force will not be eliminated. The shear force will be formed on the bolt. For a long time, the bolt will be cut off to form a seal failure.


5. Stress effects

In the flange installation, both flanges are relatively standardized, but in the system production, after the pipeline enters the medium, the temperature of the pipeline changes, causing the pipeline to expand or deform, and then the flange is subjected to tortuous load or shear force. Easy to form gasket failure.


6. Corrosion effect
Because the corrosive medium erodes the gasket for a long time, the gasket undergoes a chemical change. The corrosive medium penetrates into the gasket, and the opening of the gasket becomes soft, and the pressing force is lost, resulting in the leakage of the flange.


7. Thermal expansion and contraction
Because of the thermal expansion and contraction effect of the fluid medium, the formation of the bolt expands or shortens, so that the gasket will create a gap, and the medium will leak through the pressure.