Stacker, Shiploader, Hopper, Bucket Wheel Reclaimer Manufacturer
Pubdate：01-02-2025 Views：1231
In the mining industry, heavy duty belt conveyors are a commonly used continuous transportation device. With their advantages such as high transport capacity, smooth operation, and simple structure, they play a crucial role. Particularly, as large and ultra-large quarrying and mining projects are increasingly constructed, belt conveyors with features like high power, high throughput, intelligence, and high speed are being widely adopted.
The core of a belt conveyor lies in the conveyor belt itself, which wraps around the driving and redirecting pulleys to form a loop. Belt conveyor rollers support both the upper and lower belts, ensuring smooth material transportation. To ensure stable and orderly belt operation during start-up, running, and braking, tensioning devices are indispensable. They provide the necessary tension to the belt, ensuring sufficient friction with the drive pulley to prevent slippage and keeping the belt sag within permissible limits between rollers.
This is a belt conveyor using screw tension device.
To maintain proper operation of a belt conveyor, the tension applied to the belt must meet several specific requirements:
During the start-up phase, to meet both power transmission and sag control needs, the tension applied to the belt should be 1.3–1.5 times higher than the steady-state tension. This higher start-up tension ensures the belt remains appropriately taut during the initial moments of operation, facilitating effective power transmission and preventing excessive sag.
Once the conveyor enters steady-state operation, the belt tension significantly decreases compared to the start-up phase and stabilizes over time. This transition reflects the conveyor’s operating dynamics and ensures sustained and smooth performance.
During practical use, the load on the conveyor is not constant and can vary dynamically. For example, the belt experiences lower tension under no-load conditions, whereas tension increases significantly under heavy-load conditions. This dynamic tension characteristic requires the tensioning device to adapt flexibly, maintaining proper operation throughout.
This is a radial telescopic stacker using screw take-up device.
This device primarily consists of key components such as an electric winch, tensioning pulley, and hydraulic pump station. Its working principle is highly automated and intelligent:
When the belt tension increases or decreases, the oil pressure inside the cylinder changes accordingly. A pressure sensor detects this change and sends a corresponding signal. The hydraulic system then responds precisely according to preset programs, controlling the piston rod's movement to maintain the belt at the appropriate tension.
For example, when the belt tension decreases to the minimum set value, the pressure inside the cylinder also decreases. The sensor sends a signal, triggering the hydraulic pump station to replenish hydraulic oil to the front of the cylinder. This retracts the piston rod, thereby applying tension to the belt.
Thanks to its automated adjustment mechanism, the hydraulic automatic tensioning device offers advantages such as quick response, smooth start-up, reduced tension fluctuations, and high reliability. These attributes make it widely used in underground belt conveyor systems in China, gaining widespread recognition.
This is a hydraulic tension device for mining conveyor system.
Fixed tensioning devices can be further classified into fixed winch tensioning and fixed screw tensioning types:
The screw tensioners are widely used on our Grasshopper Conveyors, Radial Telescopic Stackers and Mobile ship loading Conveyors to provide force to the belt itself.
Fixed tensioning devices feature simple and compact structures, occupying minimal space, making them advantageous in confined underground environments. However, their main drawback is the inability to adjust tension dynamically in response to changes.
Over time, as the belt undergoes plastic deformation and elongates, its tension decreases, potentially leading to sagging and slippage on the drive pulley. Addressing such issues requires manual adjustments based on operator experience, which is inherently imprecise and somewhat blind.
Movable tensioning devices commonly include suspended counterweights, heavy-duty trolleys, and counterweight trolleys.
Movable tensioning devices effectively maintain belt sag and frictional requirements, preventing issues like drive pulley slippage or excessive belt sag. However, adjustments are manual and cannot be automated, so they are often applied to small-scale belt conveyors.
A comparison of these tensioning devices reveals notable differences and their varying impacts on belt conveyor performance:
As a critical component ensuring the efficient, safe, and stable operation of belt conveyors, selecting an appropriate tensioning device is essential. Proper consideration of sag and frictional requirements is vital. During the design and installation of belt conveyors, choosing the right type and location of the tensioning device is a prerequisite for preventing slippage and ensuring smooth operation across all stages of conveyor use. This requires careful attention and deliberate planning by all involved personnel.
