Scope of use and requirements:

1. Scope of use

This grate is a mechanized boiler layer combustion equipment suitable for boilers with an evaporation capacity of less than 25 tons per hour. It can burn bituminous coal, lignite, and peat. It uses a coal hopper to automatically drop coal; It can also be equipped with a wind powered coal feeder or a mechanical wind powered coal throwing machine by inverting the grate, becoming a mechanized semi suspended combustion chamber.

2. Usage requirements

(1) The coal quality used in this grate should meet the following requirements:

A. The maximum particle size of coal blocks shall not exceed 40mm; The content of 0-3mm coal shavings should be less than 30%;

B. The dry moisture content should be greater than 8% but less than 20%;

C. Dry ash content shall not exceed 30%, but shall not be less than 10%;

D. The deformation temperature t of ash should be greater than 1250 ℃;

E. Weak coking ability.

If the above coal quality requirements conflict with the coal feeding equipment's coal quality requirements, the highest requirement between the two should be taken.

(2) The temperature of the primary air used in the grate shall not exceed 200 ℃ (for anthracite coal, it shall not exceed 160 ℃).

The structural characteristics of the grate:

The entire grate is divided into seven parts: (1) the driving shaft; (2) Driven shaft; (3) Support (the support is an integral structure with a bottom plate of ash and friction Flat noodles); (4) Furnace chain; (5) Coal hopper; (6) Front windshield; (7) Slag stopper. Coal feeding equipment, air supply pipes, and grate gearboxes are not included in this grate.

The grate working face, also known as the surface part of the furnace chain, is composed of many furnace bars that are continuously and diagonally stacked in a fish scale shape, with a ventilation cross-section of 6%. The structural feature of the furnace chain is that it has multiple chains, and the furnace bars are fixed on the chains by clamping them in groups of 5 pieces. The chain is fixed in series with a long shaft and lining tube, and there are rollers strung between the chains. The rollers mesh with the teeth on the spindle, driving the furnace chain to operate. The operation of the grate is pushed by the active shaft, and the driven shaft is sliding. The interior of the grate adopts segmented air supply. Divide vertically along the grate into several large capacity air chambers, each of which is separately connected to the supply air duct. The wind entering the wind chamber slows down due to diffusion and can evenly fill the chamber. There are butterfly doors or open doors on the air supply duct to regulate the internal pressure and air volume inside the air chamber. The ash discharge device of the wind chamber adopts a butterfly type flip plate or push-pull or pull rod type ash discharge door. When the handle of the ash discharge door is turned or pushed, the ash will fall on the lower furnace chain. The furnace chain moves on the lower bottom plate, which can push the ash to the front end of the grate and fall into the ash hopper or slag removal tank. It is also possible to manually remove the ash, and the rotating or sliding handle of the ash door is placed outside the air supply duct through it. Its arrangement is consistent with that of the air supply duct, that is, when air is supplied on one side, the ash is discharged on one side; When supplying air on both sides, ash is discharged from both sides; Single sided air supply, but also two sided ash discharge. The sealing between the two sides of the furnace chain and the support adopts a labyrinth or contact structure to prevent coal blocks from leaking into both sides of the grate. The slag blocking device adopts an eagle iron slag blocking device. The slag stopper, also known as the eagle iron, is placed behind the driven shaft and its head is pressed against the furnace chain by its own weight. The lower part is installed on the support seat, which is welded to the grate support. For regular inspection, maintenance, and general needs, an inspection door is installed on the slope above the front windshield. If natural ventilation is required, the air door and the ash door of the air chamber can be opened. The coal hopper is installed on the wall panels on both sides of the front end of the bracket, and there is a coal gate inside the coal hopper. The thickness of the coal seam is adjusted by the lifting of the gate. This type of grate is manufactured as a complete machine and is suitable for use in fast loading boilers and integral installation boilers.

Instructions for use:

（1） On site installation of grate and adjustment before ignition

1. This type of grate belongs to the whole machine factory, and the dimensions of each part have been adjusted to the best state before leaving the factory. During transportation, there may be changes in the dimensions of the surface of the furnace chain. Therefore, before installation, it is necessary to check and adjust the levelness and related dimensions of the installation foundation of the furnace grate.

2. Due to changes in the grate during transportation, it should be carefully checked before ignition to adjust whether the bolts are tightened; Are the nuts at both ends of the furnace grate long pin loose. If it is found that it is not tight or loose, it should be adjusted in a timely manner.

3. Before ignition, the bearing shells of the driving and driven shafts must be filled with yellow dry oil using a high-pressure oil gun to prevent dry wear and damage to the bearing shells.

（2） Grate ignition

1. For the ignition of flammable coal (brown coal and bituminous coal with volatile matter not less than 20%), open the front air damper and air chamber ash door for natural ventilation in advance, then start the gearbox to operate the grate, then lower the coal door of the coal hopper, lift the coal gate, and lay a thin room of coal on top of the first air chamber of the grate. Lay 200-300mm dry firewood on the coal seam and ignite it with oil yarn. When the wood catches fire, close the front air damper and air chamber ash door, and mechanically supply air to the first air chamber. After the firewood is burned vigorously, add a small amount of coal to the burning firewood. After the coal in the first chamber is burned, the burned coal is transported to the second chamber for mechanical air supply. Afterwards, the same process will be carried out on the other air chambers.

2. Ignite coal that is not easily ignited (anthracite and coal with lower volatile matter). Lay a layer of coal with high volatile matter on the first air chamber of the grate, lay firewood on the coal seam, and follow the above process for the rest.

（3） Operation management of grate

1. The wind pressure inside the wind chamber is adjusted by the butterfly door or sliding rod door on the air supply duct. The first air chamber has a water column of 10-20mm, the last air chamber has a water column of 20-30mm, and the remaining middle air chambers have a water column of 60-80mm (this data is for reference only). Adjustments will be made according to actual conditions during operation. When adjusting the wind pressure, attention should be paid not to sharply reduce or stop supplying air to areas with strong combustion.

2. The thickness of the coal seam must be maintained at a certain level, and cannot be thin or thick at times. Coal seam thickness: For bituminous coal, it is 60-150mm, brown coal is 130-230mm, anthracite is 100-160mm, and peat can be slightly thicker than brown coal, above 220mm. The thickness of coal can increase appropriately with the increase of its volatile content.

3. The amount of coal burned is adjusted by changing the linear speed of the furnace grate, ensuring that the fuel is burned out at a distance of 400-500mm from the head of the slag blocking device. If the linear speed cannot be increased, the thickness of the coal seam can be appropriately increased.

4. Coal should be burned evenly on all parts of the grate. If there are flames or black flames, a fire rod can be used to level them. When stirring, be careful not to hook the grate.

5. Positive pressure combustion is strictly prohibited to prevent it from continuing into the coal hopper. If found, the air supply to the first air chamber should be stopped immediately.

6. If coal coking occurs, timely measures should be taken to remove it and no further growth is allowed. Pay special attention to the coking in front of the slag blocking iron and promptly remove it if found.

7. If the furnace bar is burnt or deformed, it should be replaced in a timely manner to avoid coal leakage and deterioration of combustion.

8. The ash from the lower part of the grate falls onto the bottom plate of the support. As the lower furnace chain runs forward, the ash will be pushed to the front end of the grate. Therefore, it should be checked and removed in a timely manner to prevent the ash from getting entangled between the furnace chain and the main shaft again, causing poor operation and other consequences.

9. If the nuts at both ends of the long pin of the grate are found to be loose during operation, they should be tightened in a timely manner to avoid the phenomenon of the grate falling off due to the loose chain of the grate.

10. If the furnace bar and clamp plate fall off during operation, they should be replaced in a timely manner to avoid excessive coal leakage and damage to other components.

11. The parking of the grate is generally carried out in the following order:

(1) Stop adding coal to the grate by stopping coal dropping from the coal hopper;

(2) Adjust the grate speed to quickly burn out the remaining coal;

(3) After 2-3 hours, when the ash and slag on the grate are unloaded, the ash and slag in the slag removal equipment should be removed, the air supply and induced draft should be stopped, and the front air damper and ash discharge door should be opened for natural ventilation;

（4） Maintenance of grate

1. During operation, the bearings of the rotating devices on the main and driven shafts and the coal hopper should be lubricated regularly. Pay special attention to the lubrication of the bearings on the driven shaft to prevent the lubricating oil from evaporating during overheating.

2. The driven shaft and coal gate of this type of grate are divided into two forms:

(1) Having a water cooling system; (2) When there is no water cooling system, if equipped with a water cooling system, the running water should be ensured to be smooth, and the outlet temperature should not exceed 60 ℃.

3. During operation, it is necessary to regularly clean the ash and coal leaks in each air chamber to avoid affecting the supply and induced air, as well as the combustion of coal in the air chamber. The cleaning cycle is approximately twice per shift.

4. If the furnace bar is burnt out or deformed and the furnace chain is stretched, it should be replaced in a timely manner to avoid affecting safe operation.

5. If there is any deviation during the operation of the grate, the adjusting bolt of the driven shaft should be adjusted.

6. When the furnace is shut down for a long time, the coal in the coal hopper should be removed and anti-corrosion agents should be applied to each rotating friction part.

The scale chain grate is a new type of grate developed, improved, and produced by our factory in recent years based on the large scale chain grate. It has the characteristics of compact structure, easy installation, and no need for a longitudinal slag remover. During the installation process, there is no need to install the lower guide rail or engage in underground civil engineering. Only a concrete platform can be built on the user's site. It has the advantages of good ventilation performance and convenient maintenance of large scale grate, as well as the advantages of time-saving and labor-saving installation of lightweight chain belt grate. It is a single-layer layout of integrated fast loading grate. Users have low equipment investment and installation costs when purchasing such grates. Stable and reliable operating performance, it is an ideal choice for small and medium-sized boiler factories and boiler matching use.