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During the start-up, braking, and normal operation of the conveyor belt, due to insufficient belt tension, climate, and working conditions, the conveyor belt is prone to slippage on the drive roller, causing safety accidents. The conveyor belt slippage detection device can promptly detect the slippage status of the conveyor belt, issue a slippage signal, and prevent accidents.

 

Types of Slippage Detection Devices

(1) Contact-type speed detection device

The contact-type speed detection device detects speed by using a roller to contact the conveyor belt or driven roller. When the conveyor belt runs or the driven roller rotates, it drives the roller of the speed detection device to rotate. , or the speed detection device contacts the roller through a soft connection. Roller speed detection includes simple speed relays and intelligent methods.

(2) Non-contact conveyor belt slippage detection device

The non-contact conveyor belt slippage detection device is an inductive intelligent slippage detection device that uses electromagnetic induction or Hall proximity switches to detect speed. The non-contact speed detection is installed at the end of the roller, and the sensor sends pulse signals to the control circuit for counting to detect the linear speed of the roller. The non-contact conveyor belt slippage detection device does not contact the conveyor belt, has high accuracy, and avoids damage to the conveyor belt and measurement errors caused by poor contact.

 

 

Main Technical Parameters

A Conveyor Belt Slippage Detection Device Output

Single Sensor Detection Method : Only detects the speed of the conveyor belt. By comparing the speed of the conveyor belt under stable operating conditions with the set rated speed of the conveyor belt, it judges the slippage status of the conveyor under stable operating conditions. It cannot detect the slippage of the conveyor belt during start-up and braking. During start-up and braking, the speed of the conveyor belt changes from zero to the rated speed. Therefore, the slippage detection device needs a delayed output or The PLC system does not detect during start-up and braking.

 

Dual Sensor Detection Method : Simultaneously detects and compares the linear speed of the drive roller and the speed of the conveyor belt ; When the conveyor is starting, braking, and running stably, the linear speed of the drive roller and the speed of the conveyor belt are always consistent when the conveyor belt is working normally. Only when the conveyor belt slips on the drive roller, the linear speed of the drive roller and the speed of the conveyor belt are inconsistent, thus scientifically detecting the slippage status of the conveyor belt under any operating conditions. The dual-sensor detection method can detect any operating conditions, and this comparative conveyor belt slippage detection is a complete conveyor belt slippage detection.

 

Intelligent Slippage Detection Device Can detect normal speed, overspeed, or underspeed (slippage). The control instrument panel can display the running status of the conveyor: light slippage, heavy slippage, light slippage alarm signal, and heavy slippage trip shutdown signal; it can output two pairs of normally open and normally closed switch quantities, and the relay contacts provide light slippage alarm and shutdown signals; if needed, it can output a 420mA analog quantity, which can be used to network with the host computer or programmable controller for centralized control.

 

B Setting of Conveyor Belt Slippage Value

When the conveyor belt slips, light slippage alarm and heavy slippage shutdown signals are usually set. Conveyor belt slippage (underspeed) is expressed as a speed slip rate (the ratio of the difference between the actual speed of the conveyor belt and the set value to the set value). The speed slip rate values for alarm and shutdown should be determined according to the conveyor parameters, conveyor belt tension, belt speed, etc.

Intelligent conveyor belt slippage detection devices generally have adjustable speed slip rate and adjustable delay functions.

GB50431-2020 stipulates that the functions of the conveyor belt slippage detection device should meet the following regulations:

1 For large long-distance belt conveyors, a conveyor belt slippage detection device that detects the entire process of starting, stable operation, and braking of the belt conveyor should be used.

2 The allowable slip rate of the conveyor belt should be determined according to the conveyor belt tension, belt speed, etc. Belt conveyors with high conveyor belt tension should be selected according to the following regulations:

1) Alarm signal: speed slip rate greater than or equal to 8%;

2) Shutdown signal: speed slip rate greater than or equal to 8% and running time greater than or equal to 20s, or speed slip rate greater than or equal to 12% and running time greater than or equal to 5s.