What Are The Reasons For The Failure Of The Chain Grate?

(1) The material requirements are not high. In order to reduce the cost, HT200 is mostly used for the sealing iron on the side of the grate, and its heat resistance temperature is low, which may easily cause high temperature burning and deformation of the chain. Due to the high temperature in the furnace, it should be made of heat-resistant cast iron. Such as RQTA122, it can withstand heat up to 1100℃ in air furnace gas. The main chain of the grate should also be made of heat-resistant cast iron to ensure long-term good mechanical properties.
(2) The manufacturing accuracy of the grate is not high, and the error is large. As a fast-installed boiler, the flatness of the front and rear axes of the grate affects the resistance of the grate and the average stress, which may easily cause the grate to deviate and break. When the grate deviates, there are no reference marks for the adjustment of the bolts on both sides. It is only based on experience, which causes inconvenience to the user.
(3) The tooling error of the active chain teeth of the fire grate is large, resulting in wear of the chain teeth, tearing of the fire grate, arching, and bending of the fire grate shaft due to uneven force. The sprockets are not calibrated uniformly when inserting and milling the keyway or the order is wrong during assembly, resulting in sprockets being out of sync. For example, a 10t/h boiler has a sprocket error of 12mm. During the operation of the boiler, the grate is often torn in a large area, and the grate shaft is bent. It has to be overhauled comprehensively, which is time-consuming and laborious.
(4) The ash falling device in the air chamber needs to be improved urgently. Timely removal of accumulated dust in the air chamber is conducive to normal air supply, and the furnace beam can be cooled. If the falling coal ash is not removed in time, it will burn due to the high temperature in the furnace and burn out the furnace beam track. In addition to the correct and timely operation of the operating personnel, the ash shaker handle or pull rod should be labor-saving and reliable, the ash falling board should be made of the whole board, the friction surface should be polished, and the influence of thermal deformation should be fully considered. In addition, the first air chamber is the preheating and drying stage of coal, the required air volume is small, and it is generally closed during operation, and the leaking ash is mostly fine coal, which is easy to burn. It was found that several boilers had over-burned and deformed furnace beams for many times, most of which were concentrated in the first and second air chambers. Later, the first air chamber was closed during maintenance to prevent coal leakage, and the use effect was good.
(5) The air volume control of the damper is rough. Due to the baking of the grate, the temperature at the damper is generally around 100°C. Affected by expansion and contraction, the parts are easily deformed, resulting in failures such as loose closing and inconsistent opening.
(6) The lubrication method of the front and rear axles needs to be improved urgently. The front and rear large shafts mostly use bearing bush sliding friction, lubricated with grease, and generally consist of 4 to 8 oiling holes. Since the working temperature of the front and rear major shafts is around 100°C, ordinary calcium-based grease is easy to solidify, so temperature-resistant grease should be used. But the oil passage is too thin and too long, so it is still very difficult to refuel. Some boiler rooms try to use 30# engine oil cup instead, and the current effect is good.
(7) Improper maintenance during operation. The working quality of the boiler staff in many units is low, lack of knowledge about boilers, and some have a weak sense of responsibility, such as untimely cleaning of dust, resulting in poor ventilation and lack of oil in the oil cup, resulting in poor lubrication. Many small faults are not discovered in time, and eventually lead to accidents.
(8) There are problems in leadership management. If the prescribed type of coal is not used, so that the boiler is not suitable for coal combustion, regular inspection and maintenance will not be done. Improper reduction of stoker operators.