20t/h High Wall Chain Belt Type Grate

Product introduction

In a chain-belt grate the chain belt itself forms the grate surface. The chains are driven by sprockets, which move the grate slowly. The grate plates are usually made of cast iron. After assembly the necessary ventilation gaps are kept between the plates, and an independent air chamber with adjustable air volume is usually provided under the grate, so that air can pass through the gaps into the fuel bed for combustion. Coal falls evenly onto the grate from the coal hopper at the front of the grate, and the thickness of the coal layer is adjusted by raising and lowering the coal gate.

As the grate moves backwards, the coal layer is ignited, burned and finally burnt out in turn. The ash left after combustion is discharged manually or mechanically. There are also designs that do not feed coal from a hopper but use a coal spreader to throw the coal onto the rear part of the grate while the grate moves forwards. The travelling speed of the grate is adjusted through gear transmission according to the coal type and the boiler load.

Applicable scope and requirements

Scope of application

The chain-belt grate is mechanized layer-combustion equipment and can be supplied with boilers having an evaporation capacity of 1-25t/h, and can also be used for various heating and drying equipment. It is suitable for burning bituminous coal, lignite and peat. After special design it can also serve as biomass fuel combustion equipment burning bagasse, wood, rice husk and other materials.

Use requirements

The coal burned in this grate shall meet the following requirements:

(1) The maximum particle size of the coal shall not exceed 40mm, and coal fines below 0-5mm are not recommended.

(2) The moisture content of the coal shall be less than 20%, preferably 8-10%.

(3) The ash content of the coal shall not exceed 30% but shall not be lower than 10%, and the volatile matter content shall not be lower than 20%.

(4) The ash melting temperature of the coal shall be higher than 1290℃.

(5) The caking tendency should not be too strong.

(6) The net calorific value of the coal should not exceed 4226kcal/kg.

(7) If the above coal quality requirements conflict with the coal feeding installation, the upper limit value shall be taken.

The primary air temperature used for this grate shall not exceed 200℃.

Structure and characteristics

Components: 1. drive shaft; 2. driven shaft; 3. frame; 4. ash removal device; 5. air regulating device; 6. furnace chain; 7. coal hopper; 8. front air damper; 9. side seal.

(1) Simple structure, low metal consumption and a large air passage ratio; high requirements are placed on the strength and performance of the drive shaft, the driven shaft and the grate plates.

(2) Inside the grate, several mutually isolated independent air chambers are arranged along the length. After the primary air enters a chamber its velocity drops because of diffusion, and it fills the whole chamber evenly. The air flow into each chamber can be regulated by the air regulating device.

(3) Each air chamber is fitted with an ash removal device. At the bottom of the chamber there is an ash discharge bottom plate with an ash outlet, and a movable door connected to the ash discharge tie rod normally covers the ash outlet. When the ash removal handle is pulled at intervals, the ash falls from the outlet onto the furnace chain below, and the furnace chain carries it to the front or to the ash receiving hopper near the ash discharge door, where it is finally removed by hand.

(4) The grate runs normally once commissioning is completed at the partner factory, and it can be shipped as a whole unit or in separate parts as the user requires.

Model parameters

Operating features

1. Compared with other chain-belt grates, metal consumption is lower and the structure is simpler, which makes manufacture, installation and operation easier;

2. The chain-belt grate runs reliably, burns stably and accepts a wide range of fuels, so it is widely used in industrial boilers.