Becker Electronics manufactures belt protection systems that automatically detect tears or rips in conveyor belts used in demanding mining applications.
“This belt rip scanner system type BRS-01, which is used to detect longitudinal rips on steel cord and fibre conveyor belts, also prevents further damage to the belt by stopping the belt drives in the event of a rip,” Albert Bower, director of Becker Electronics, part of the Becker group of companies, says. “This system works on the principle of secondary rip detection – rips are only detected after they have occurred. This scanner minimises damage to short belt distances, typically 50 m, thus preventing further damage to the belt. ”
Inductive coils, which are selected according to belt width and rubber type, are encapsulated in a rubber flap and embedded into the belt to efficiently monitor steel cord and fibre belts.
At installation, the system carries out an identification run and the processor of the belt rip detection system unit (BRS/CU) stores the necessary data in the EEPROM. Parameters include the succession of coils in the belt, belt speed and start up time of conveyors. Stored values are protected against power loss and can be entered or changed when necessary.
When the belt is in operation, these coils pass over the transmitter and receiver which are positioned opposite each other on either side of the belt. An eletromagentic signal is transmitted via the inductance coil from the transmitter into the receiver. Because this system has recorded the distance between successive coils and belt velocity, it can automatically calculate the time intervals between each coil.
The belt rip sensor that is embedded in the belt operates like a bridge between transmitter and receiver of the belt rip scanner sensor interface (BRS/SI). If a belt is ripped, the BRS/ SI cannot measure any analogue values from the destroyed coil.
A belt rip scanner proximity switch interface (BRS/PSI) counts the impulses from the belt idler and transmits them to the master BRS/ CU. In the event of a belt rip, the appropriate coil will go open circuit and thus prevent a signal from being transmitted.
The BRS/CU acknowledges this as a fault and switches off the motor drive and stops the belt.
The number of inductive coils required to protect the conveyor depends on each specific application. In the event of a rip, where coils are embedded in short distances – between 15 m and 20 m – the maximum tear in the belt will only be 20 m. In surface conveyors, coils are usually integrated every 100 m – 200 m and in underground installations, distances between coils do not exceed 80 m. For important and hazard exposed belt conveyors, the recommended distance range is between 10 m and 50 m.
Apart from the detection of belt rips, this system is designed for monitoring belt speed, the detection of belt slip and also for belt sequence control