Dymot Engineering Company was part of a Project in Finland to brake the high momentary loads that arises in the conveyor system. A Braked Capstan was installed and solved the issues experienced that was present.
CONVEYOR DATA:
- Length 2185m
- Width of the belt 1600mm
- Speed of the belt max 2,7m/s
- Capacity calc. 3750 tn/h
- Material: Nickel or size 0…230mm
- Motors: 3 x 630kW
- Elevation gain from tail to head 57,5m
SPECIFICATIONS
MAX. Momentary Tension (Carriage): 240kN
MAX Brake Capacity: 150kN
Brake Wheel: 3 Grooved 730mm Root Diameter
Idler Wheel: 2 Grooved 585mm Root Diameter
Disc DIA: 1450mm
Rope DIA: 32mm
PROJECT BRIEF
- The Capstan had to be designed to withstand the extreme cold weather up to – 40°C. Special steel and oil was required to operate at this extreme conditions.
- Special instruments with retransmission was used and tank heaters to keep the oil in an acceptable range. This is used to monitor all levels and temperatures.
- The caliper brakes is fitted with Open/Close and Wear Proximities to monitor the brakes.
- The unit was installed on a Vertical Plane so all equipment needed to be mounted to suit this position.
- The Braked Capstan was successfully commissioned and is performing to the client requirements.
GENERAL INFORMATION ON BRAKED CAPSTANS
The Braked Capstan is developed to work in conjunction with a Horizontal Gravity Take-Up system. The purpose of the braked capstan in a conveyor tensioning rope system is to prevent the shock loads, caused by power failure or emergency stops, from pulling excessive rope from the system and causing the counterweight to hit the top of the tower.
This is achieved by wrapping the rope through a braked and grooved bull wheel system. The hydraulically released calliper disc brakes are held in a normally off position and fail to safe in the event of a power loss. This is controlled by a hydraulic power pack. An electric control panel is supplied to control the power pack or a junction box can be supplied where the mine’s PLC controls the power pack.
The rope force then has to drive the bull wheel through the preset brake torque with a resultant loss of energy. With the brakes off the bull wheels are free to turn and the gravity system will tension the belt in the normal way.
In the event of a conveyor power failure or emergency stop, the power supply to the power pack is lost and the calliper brakes close (Power Off – Brake On). The momentary shock load arising from the conveyor will be absorbed by the capstan brake and will not pass through to the take-up tower.
Braked Capstans
The Braked Capstan is developed to work in conjunction with a Horizontal Gravity Take-Up system. The purpose of the braked capstan in a conveyor tensioning rope system is to prevent the shock loads, caused by power failure or emergency stops, from pulling excessive rope from the system and causing the counterweight to hit the top of the tower.
