Material Clearance Control
(Measure for clearing the closing area)
During the specialist testing required in the general technical approval (e.g. VdS-acceptance test) the below described case is simulated:
The closing area of the conveyor system shutter is covered with material to be conveyed.
The main supply is disconnected.
Smoke alarm is released.
Under those conditions the material to be conveyed and possibly the conveyor system shall be removed out of the closing area by means of appropriate measures (standard time approx. 2 minutes) and subsequently the shutter shall be closed.
Appropriate clearing measures are:
Clearing by means of a inclined conveyor segment
Mechanical clearing equipment
Material clearance control
Depending on the design the material clearing control takes over the control of the conveyor system motors in the safety zone in the event of fire or failure or in case the shutter shall be closed. It insures that the material covering the closing area is removed and subsequently the shutter can be closed. In the event of the situation that the actual capacity of the emergency power supply is not sufficient for a simultaneous clearing of all areas a succession will take place. In that case meeting the specified closing time of two minutes applicable for all shutters in a fire section shall be considered.
Depending on the available conveyor system control various designs are possible. When deciding which of them is supposed to take over the material clearance control one must consider that the control duty is to be accomplished in case of power breakdown too. That means that the material clearance control must be equipped with a replacement power supply battery.
Versions of controls for conveyor system motors:
Direct control – Control of the drives through fire technology in conformity with the signals of the conveyor system.
Indirect control- Looping through of the power cable via the control of the fire technology.
Control via bus systems - e.g. Movimot, Movi-Switch, or MQP modules etc.
Due to the great number of applications a discussion with our control engineers for a definition of the most advantage version for your project will surely be very helpful.