Unlike other conveying equipment, the pneumatic conveying system do energy transfer by air to realize material delivery. While this kind of energy transfer, make the material has a movement speed, so easily to generate collision and friction with inter pipe wall through the process of passing pipe bending, thus affect the bending pipe abrasion resistance. There are both external and internal factors influencing the wear resistance of the bending pipe.

1. External Factors
In the pneumatic conveying system, the greater the air flow, the higher the frequency of contact between the material and pipes.　The ratio of material and air is means the ratio of material quality and the air quality consumed during material conveying.  When the material and air ratio is big, the collision or friction frequency of the material with the pipe wall will more bigger, thus causes the pipe wall to be seriously worn down. In addition, the physical properties of the materials can also affect the ware of the elbow. For example, if the material has larger particle size or greater hardness, the ware of the bend will be more serious.

2. Internal Factors
From the bend Angle design, both the bending structure and the roughness of the inner wall will affect the wear of the bending pipe. First of all, when the ratio of bend radius of curvature and pipe diameter is larger, the material is easy to bounce when through the bend, which leads to violent collisions between material and bend, and changes the direction of material movement. This type of collision will cause the material to be broken and produce energy loss, which will cause the bending tube to form a point of wear. If the curvature radius of the bending tube is small, the energy loss can be reduced, thus reducing the wear of the pipe. Secondly, under the condition that the inner wall of bent tube has a large roughness, the inner part of the bent tube will have larger Friction resistance, therefore, in the process of material passing, it will consume a large amount of energy, which will cause the bending pipe to wear out seriously. Furthermore, under the condition that the pipe has a smaller diameter, the air flow will be subjected to greater resistance, and it needs larger amount of energy when material passing, which in turn can cause the ware of bending pipe to be more serious. In addition, in the case of bending pipe bending Angle is large, it takes longer for the material to pass through the bending pipe, which need more energy, so it will cause the bending pipe to wear out.

The use of the bending tube allows for more flexibility in the pneumatic piping system, but It is also lead bending pipe wear, material damage and pressure drop, etc. To strengthen bending wear mechanism and analysis of influencing factors and take effective measures to improve bending wear resistance can improve these conditions.
                                                                                                        
                                                                                                                                                                                                                                                                                                                                                               --by Grace