Flanges are pipe fittings that are often used to connect pipes and pipes or to connect two equipment in the pipeline system. There are many types of flanges, such as threaded flanges, welding neck flanges, plate welding flanges, etc. (collectively referred to as flanges). However, in real life, you can also notice that there is another flange product called blind flange. What is the difference between common flange and blind flange? How to install and use the blind flange?
1. Difference between flange and blind flange
(1) There are holes on the flange. During the connection, the two flanges need to be fastened with bolts. The flange is sealed with gaskets to play a role of sealing, or play a temporary role in the experiment;
The blind flange is composed of casting or threaded connection or welding. It is a flange without holes in the middle. It is mainly used to seal the front end of the pipe, and to seal the pipe orifice. Its function is the same as that of the head and the pipe cover, and it plays the role of vibration isolation and cutting. However, the blind flange seal is a removable sealing device. The seal of the head is not ready to be opened again. The blind flange can be removed to facilitate the reuse of the pipe in the future.
(2) Because flange has good performance characteristics, it is often widely used in chemical engineering, construction, petroleum, sanitation, pipeline, fire protection and other basic projects;
It is necessary to set blind plates at the connection of equipment and pipeline, especially at the boundary area outside the boundary area where various process material pipes are connected. However, in the pipeline strength test or sealing test, it is not allowed to apply blind plates at the same time as the connecting equipment (such as turbine, compressor, gasifier, reactor, etc.) in the initial start-up preparation stage.
But in fact, there are many similarities between flanges and flange blind plates. For example, there are many types of sealing surfaces, such as plane, convex, concave and convex, tenon and groove, and ring connection surfaces; It is used for flange connection, consisting of a pair of flanges, a gasket and several bolts and nuts. The gasket is placed between two flange sealing surfaces. After tightening the nut, the specific pressure on the gasket surface reaches a certain value, which will cause deformation, and the uneven parts on the sealing surface will be filled to make the connection tight.
2. Installation and use of flange blind plate
The flange blind plate can also be connected by flange, that is, the gasket is placed between the two flange sealing surfaces. After the nut is tightened, the specific pressure on the gasket surface reaches a certain value, and the deformation occurs, and the uneven places on the sealing surface are filled, so that the connection is tight. However, the flange blind plate with different pressure has different thickness and uses different bolts; In the case of oil medium system, the flange blind plate does not need to be galvanized, but in the case of other medium systems, the flange blind plate shall be subject to hot galvanizing treatment, the minimum weight of zinc coating is 610g/m2, and the quality of the flange blind plate after hot galvanizing shall be inspected according to the national standard.
The above is the difference between flange and blind flange and the installation and use of blind flange. I hope it can help you select and install the flange correctly and play its sealing role.
Post time: Mar-16-2023
