Cement bucket elevator often uses ordinary electric protection device: air switch, thermal relay, etc., only for overload, over-current protection, and for the mechanical transmission device often appear plugging turn, blocking,overload, belt slippage, chain disconnection, shaft fracture and other mechanical failure can not be implemented to protect, which requires some special protection measures.
Cement bucket elevator inlet blockage fault can be judged by a film type level switch, which uses a pressure micro switch placed in the cavity with rubber membrane, installed in the position of the highest material level limited, generally slightly higher than the bottom line of the driven drum, when the material level reaches the switch and squeeze the film, its output switch signal into the PLC or the main control circuit, according to the set delay time (generally 3 - 5s), control the main motor stop.
For the Cement bucket elevator, it is also necessary to set the belt sway switch at the drive and driven end, that is, to install two belt sway switches at the rising end of the bucket and on each side of the head and tail frame. when the belt is deflected due to the bucket feeding offset, etc., the belt makes this end contact switch action, and its signal enters the main control circuit, when it exceeds the set delay time of about 3-5s, it is judged to be continuous deviation and unable to rectify itself, the main motor is controlled to stop.special attention should be paid to the location of the belt sway switch,due to the processing and installation error of the drive and driven pulley, the belt has a certain normal deviation on the drum, and this deviation must be taken into account when positioning.
In addition, for heavy-duty high-efficiency Cement bucket elevator, the main transmission device is protected by a hydraulic coupling, and a torque-limiting hydraulic coupling with a plummer coupling is used between the motor and the reducer. When the operation is overloaded, the oil temperature in the fluid coupling rises to reach the melting point of the safety pin, the temperature is generally 120 ℃, the fusible alloy melts, the working oil spurts out, and the motor is disconnected from the driven part. Of course,temperature alarm and safety monitor can also be installed on the fluid coupling, when the temperature reaches the critical value of the need for protection, sound and flash alarm will be issued immediately, and the power supply will be cut off at the same time.
Bucket elevator is an important material conveying equipment for cement enterprises and has been very widely used. Due to the high requirements of cement production continuity, it is important to reduce the occurrence of various equipment failures as much as possible. Generally large special equipment with self-protection and and report replacement system, especially for the design of the above special protection measures is particularly important, can greatly reduce the failure rate of equipment.
