Common tensioning devices include side pull tensioners, tarp tensioners, screen tensioners and wire tensioners. Specifically as follows: 1 Spiral tensioning device. Spiral tensioning device has a simple structure and the tensioning stroke is too small, which is only applicable to short distance conveyors. When the general length is less than 80m, the disadvantage is that when the tape is self-extending, it cannot be automatically tightened. 2 Gravity tensioning device. Gravity tensioning device is the most simple and widely used tensioning device. It uses weight to automatically tighten. Since the weight is tensioned by its own weight, it ensures constant tension under various operating conditions and automatically compensates for tape elongation. The gravity tensioning device is characterized by a constant tension and variable tension and displacement. It is suitable for fixed long-distance transporters. The advantages are high safety and reliability. Disadvantages are that tension cannot be adjusted, space requirements are high and space is compromised. Restricted places can not be used. 3 Fixed winch tensioning device. Fixed winch tensioning device by a small winch tensioning. The winch usually uses a worm gear reducer to drive the reel to wind the wire, thus tightening the tape. The tensioning device is small in size and has a large pulling force, and is widely used in underground belt conveyors. The disadvantage is that it can only produce a fixed tension according to the required tension. The tension cannot be adjusted automatically. When there is a problem with the winch and the control system, the belt conveyor cannot produce a constant tension or pulling force. The fastening force fails and safety and reliability are relatively reduced. 4 Automatic tensioning device. The automatic tensioning device not only automatically adjusts the tension according to the traction force of the active roller, but also compensates for the elongation of the tape. Automatic tensioning device consists of motor, brake, reducer, wire rope drum, etc. The tensioning unit is tensioned by a large tensioning device and a tension sensor is used to measure the tension of the conveyor belt. When the tension of the conveyor belt changes, the conveyor belt is normal. When the range is running, the automatic tensioning device moves quickly to adjust the tension of the conveyor belt to ensure the normal operation of the conveyor belt. The automatic tensioning device is used in conjunction with the tail of the automatic moving machine to achieve movement of the conveyor tail and expansion and contraction of the conveyor belt without stopping the conveyor, greatly improving conveyor speed. The efficiency of the conveyor. The automatic winch tensioning device automatically controls the tensioning force according to the needs of the belt conveyor operating conditions. The hydraulic tensioning device applies the tensioning force to the belt conveyor by means of hydraulic pressure generated by a hydraulic station. Operating conditions require adjustment of tension.