Why is the chain grate stuck and stopped during the operation of coal-fired boilers?

Question details (Performance) :

1. The vibrating coal grate stops running totally or intermittently.

2. The current of vibrating coal grate motor rises abnormally.

3. The safety clutch of transmission machine of grate or safety pin is broken.

Answer: cause of the problem:

Boiler’s vibrating coal grate is a rotating combustion equipment, due to the bad working conditions, stuck stalling is easily happened and grate failure happens in daily application and needs a lot of maintenance. The event of a failure is mainly: motor current increases suddenly, grate safety clutch spring vibrating or safety clutch opens, and makes abnormal sound. The boiler manufacturing quality material is an important reason of the grate fault. Improper adjustment on either side of the vibrating coal grate cause the left and right sides of the chain length is different, the flatness of front and back axle of grate affects grate resistance during moving and uniform stress, which is easy to cause fire grate deviation, fragment, grate broken, so as it is moving, sometimes it is stopped by edge block, sometimes the whole piece falls, makes slag plate sinking to resist fire grate. Prevent normal operation of the vibrating coal grate and sometimes even the grate will be stuck or broken badly.

Trouble shooting:  

Handling of vibrating coal grate stuck fault: when chain grate gets stuck, shall immediately cut off the power and stop operating, find out the reason, eliminated them. Use special wrench to overturn grate a distance (revert commonly 2 ~ 3 groups of grates), if no more abnormalities then keep running. After starting, if the chain still appear jam phenomenon, can check the grate fastening of compression spring, when it is necessary to tighten, then restarting, if no stuck, then keep running. When it still can't start up after repeated two or three times, should immediately stop the furnace for maintenance. If large pieces of the cinder stuck grate, can pry stick break cinder through the fire door, or lift fire blocked ash board tip, let cinder fell into ash hopper, if it can't recover operation, should stop the furnace for overhaul. The timely elimination of ash accumulation in the air chamber is conducive to normal air supply and the furnace beam can be cooled. The coal ash will burn due to the high temperature in the furnace and break the beam rail. The boiler operator should operate correctly and timely, the ash shaker handle and the puller rod should be reliable and easy to use, the ash drop plate is best made of the whole board, the friction surface should be polished and processed, and the influence of thermal deformation should be fully considered. The boiler should be stopped for repair if grate gearbox has problem and makes grate stops.

Vibrating grate is a new type of mechanized combustion equipment that has been applied to small industrial boilers in China since 1960s.