大型工业风扇因为扇叶的叶片长度较长、叶片较重，使叶片的根部连接承受更大的载荷，叶片根部结构尺寸大，而叶片根部是整体结构的薄弱环节，连接的失效模式多，且强度预测较困难，所以叶片的根部连接至关重要。

      目前市场上工业风扇叶片根部的连接方式主要有三种：T型螺栓连接、预埋螺栓连接、植入式螺栓连接。

      T型螺栓连接，是与根部端面垂直沿圆周方向均匀打制一圈螺栓孔，并在螺栓相应的方位上，沿径向与螺栓孔垂直方向打一圆螺母孔。双头螺杆一端与圆螺母连接，另一端与安装于轮毂上的轴承连接，双头螺栓和螺母成T型结构，故而这种连接称为T型螺栓连接或交叉螺栓连接，这是一种参考大型发电风车设计的连接方式。由于螺栓孔和圆螺母孔是在叶片成型后打制的，打孔精度也由设备保证，在风扇叶片制作时不需要考虑根部连接问题，也不会因为在叶片制造过程中的固化收缩等问题而影响根部连接精度，因而叶片的制造也相对简单，特别适合流水线生产工业风扇叶片的公司。

      预埋螺栓连接，由预埋螺栓套和双头螺杆组成。预埋螺栓套外表面有波浪状或齿状环形凸起，并表面喷砂处理以提高表面的清洁度和粗糙度，在使用前用连续玻璃纤维束缠绕填平沟槽。因叶片根部是两个半圆柱合模粘接而成，合模精度也直接影响到螺栓连接精度。预埋螺栓连接的叶片根部端面一般不再做修整，平面度是靠成型和合模后的模具端面的平面度保证。因而预埋螺栓连接的制造对模具根部的刚度、预埋螺栓定位工装的制造精度及结构合理性，以及叶片模具的合模精度、制造工艺提出了更高的要求，也增加了叶片出现质量问题的概率。

      植入式螺栓连接，是在叶片根部端面按要求打制轴向连接螺栓孔，将钢连接锚杆植入轴向连接螺栓孔，并用环氧粘接剂粘接。但该种方式使得钢连接锚杆无法更换，一种改进的方法是在轴向连接螺栓孔中植入类似于预埋螺栓套的连接件，再用双头螺杆与主机连接。

   
  
Because the blades of the large industrial fans are longer and the blades are heavier, the root connections of the leaves are subjected to greater loads. The root structure of the leaves is large in size, and the root of the leaves is the weak link of the overall structure, and the failure mode of the connection is many. And the intensity prediction is more difficult, so the root connection of the blade is of great importance.
At present, there are three main ways to connect the roots of industrial fan blades on the market: T-type bolt connection, pre-bury bolt connection, and implanted bolt connection.
The T-type bolt connection is to make a circle of bolt holes vertically along the circular direction with the root end surface, and to make a round nut hole along the radial direction and the vertical direction of the bolt hole in the corresponding orientation of the bolt. One end of the double-headed screw is connected to the round nut, and the other end is connected to the bearing mounted on the hub. The double-headed bolt and nut form a T-type structure. Therefore, this connection is called a T-type bolt connection or a cross-bolt connection. This is a connection method that refers to the design of a large-scale power-generating windmill. Since bolt holes and round nut holes are made after the blade is formed, the drilling accuracy is also guaranteed by the equipment. The root connection problem does not need to be considered when making fan blades. Nor will it affect the root connection accuracy due to problems such as solidification and contraction in the process of blade manufacturing. Therefore, the manufacture of blades is relatively simple, and it is particularly suitable for companies that produce industrial fan blades in pipelines.
The prebury bolt is connected and consists of a prebury bolt sleeve and a double-headed screw. The outer surface of the prebury bolt sleeve has a wavy or dentate ring bulge, and the surface is sand-sprayed to improve the cleanliness and roughness of the surface. The groove is filled with continuous glass fiber bundles before use. Because the root of the blade is bonded by two semi-cylindrical mold, the precision of the mold bonding also directly affects the bolt connection accuracy. The end surface of the blade connected by the pre-bury bolt is generally no longer trimmed, and the plane degree is guaranteed by the plane degree of the end surface of the mold after molding and die. Therefore, the manufacture of pre-bury bolt connection has put forward higher requirements for the stiffness of the root of the mold, the manufacturing accuracy and structure rationality of the pre-bury bolt positioning assembly, and the precision of the mold closing and manufacturing process of the blade, and also increases the probability of quality problems of the blade.
Implantable bolt connection is to make axial connection bolt hole at the end of the blade as required, insert the steel connection anchor into the axial connection bolt hole, and glue with epoxy adhesive. However, this method makes it impossible to replace the steel connection bolt. One improved method is to insert a connector similar to a pre-buried bolt sleeve in the axial connection bolt hole, and then use a two-headed screw to connect to the host.