Walker control
The operation of a longwall face requires considerable amounts of energy. This is typically provided underground by the energy and supply trains running on overhead monorail systems.
As the face inevitably advances continuously it is necessary to move the supply train along. Due to the considerable weight and the dimensions of the train this is done by means of walkers. These are pairs of trolleys connected by means of a cylinder. They are suspended from a rail in the entry. For the forward movement, the rear trolley clamps in place at the rail.
The cylinder extends and pushes the front trolley forward. In the next step, the front trolley clamps in place in the rail. The rear trolley now lets go off the rail and is pulled forward by the cylinder. This procedure is repeated until the required distance has been covered.
Depending on the dimensions and the weights of the loads to be moved several walker pairs can be connected.
Control unit
A modified shield control unit ASG5 is used to control the advancing movement. In contrast to the standard ASG5 for the control of shields this modified unit uses a special software as well as an adapted keypad layout. The ASG receives[...]
A modified shield control unit ASG5 is used to control the advancing movement. In contrast to the standard ASG5 for the control of shields this modified unit uses a special software as well as an adapted keypad layout.
The ASG receives wireless control commands from the radio remote and activates the valve solenoids iEA27 accordingly.
iLED
Each walker is equipped with a bar of signal lights of type iLED. Depending on the number of walkers used up to eight iLEDs can be installed. The lights are numbered and clearly indicate to the operator which control unit or which walker is[...]
Each walker is equipped with a bar of signal lights of type iLED. Depending on the number of walkers used up to eight iLEDs can be installed. The lights are numbered and clearly indicate to the operator which control unit or which walker is currently being active and can be operated.
Hydraulic control
The electrical signals of the control unit are converted by means of a valve solenoid iEA27. This solenoid via its pilot valves operates a specially developed hydraulic two-function control block. The latter in turn acts on the hydraulics of[...]
The electrical signals of the control unit are converted by means of a valve solenoid iEA27. This solenoid via its pilot valves operates a specially developed hydraulic two-function control block. The latter in turn acts on the hydraulics of the pair of walkers.
Radio remote
The walkers are exclusively operated by means of a radio remote. The operator can monitor the sequence of movements from a safe distance and thus has a better overview over the complete energy and supply train. The operation works according[...]
The walkers are exclusively operated by means of a radio remote. The operator can monitor the sequence of movements from a safe distance and thus has a better overview over the complete energy and supply train.
The operation works according to the dead man’s principle. That means, a walker will only move as long as the operator keeps pressing the respective key.
Reed contact rod
When several walkers are used the distance between the pairs of walkers may change while moving through the entry. This may e.g. be caused by different length clearances of the cylinders or by external factors. In the worst case e.g. a walker[...]
When several walkers are used the distance between the pairs of walkers may change while moving through the entry. This may e.g. be caused by different length clearances of the cylinders or by external factors. In the worst case e.g. a walker could push part of the energy train into the walker ahead.
In order to prevent this happening the possibility is provided to integrate reed contact rods into the walker control. They are either installed into the cylinders or are located between two pairs of walkers. Thus, the control units can perform a target/actual value comparison at any time and make corrections, if necessary.