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Function 1 of the belt conveyor tensioning device: to ensure that the conveyor belt remains tightly attached to the drive drum, so that its exit end has sufficient tension to enable the required pulling force to be transmitted. It generates the required friction between the drum and the tape to prevent the conveyor belt from slipping. 2. Ensure that the tension at various points on the conveyor belt remains above a certain level, in order to prevent the belt from becoming excessively loose and sagging between the idlers, which could lead to material spillage and increased operating resistance. 3 Compensate for the plastic elongation under tension and the changes in elastic elongation under transitional operating conditions of the conveyor belt. 4 provides the necessary margin for rejoining the conveyor belt. Requirements for the layout of belt conveyor tensioning devices: 1. The tensioning device should be placed as close as possible to the point where the belt tension is at its lowest. For horizontal conveyors with a length of over 300 meters, or inclined conveyors with a slope of less than 5°, the tensioning device should be located on the unloaded branch right next to the drive drum ； For conveyor belts with a short distance and a slope of over 5°, the tensioning device should be installed at the tail end of the conveyor belt. 2 The tape should be wound on the tensioning drum in a direction parallel to the drum’s displacement line, at both the inlet and outlet points, and the applied tension force should pass through the center of the drum. Several common tensioning devices for belt conveyors and their characteristics 1. Car-type tensioning device: This type of tensioning device installs the tensioning drum at the rear of the belt conveyor on a car, which moves along horizontal or inclined guides. The car uses a wire rope and guide pulley system to pull the belt downward; the weight of this downward force generates the tensioning force, enabling automatic adjustment of the belt tension and ensuring that the belt maintains a constant level of tension under various loading conditions. 2. The characteristic of this type of tensioning device is that it can be used with longer conveyor belts; the pulling stroke is not limited, it has high power, a simple and reliable structure, and it can also automatically maintain the preload force. 3. Vertical tensioning device: The vertical tensioning device consists of two direction-changing drums and one tensioning drum; it can be installed at any position on the return belt of the conveyor. Under the action of gravity, the tensioning drum and the sliding frame move together along vertical guides. 4 Features: The vertical tensioning device is used on conventional belt conveyors and reversible belt conveyors; it allows for a large tensioning stroke and can be applied to longer belt conveyors. The reference for the planar layout of the belt conveyor’s automatic hydraulic tensioning device is shown in the figure. It consists of five main parts: a hydraulic pump station, tension cylinders, an energy storage station, an explosion-proof and intrinsically safe control box, and accessories. The tensioning cylinder is connected to the tensioning trolley via a movable pulley and a steel wire rope. 2 Features 1) The tension at startup and the tension during normal operation can be adjusted as needed to meet the tension requirements of the belt conveyor (the adjustment range is specified in the table according to the selected model). It is entirely possible to meet the requirement that the tension at startup be 1.4–1.5 times higher than that during normal operation; once adjusted, it operates automatically according to a predetermined procedure, ensuring that the belt functions under ideal conditions ； 2) Fast response: When the belt conveyor starts, the loose end of the belt suddenly relaxes and stretches; this device can immediately retract the cylinder to compensate for the stretching of the belt in a timely manner, exerting little impact on the tight end, thereby ensuring a smooth and reliable start-up. Prevent tape breakage accidents ； 3) It has protective functions such as automatically stopping the belt conveyor in case of belt breakage, and automatically increasing the tension in case of slippage ； 4) Compact structure, requiring little installation space ； 5) It can be connected to a central control unit to enable remote centralized control of the machine, as well as microcomputer control.