80t/h Cross-beam Type Grate

Product introduction

The cross-beam grate is a new type of cross-beam grate plate in which oblique air outlets are applied on the cross-beam grate plate. This type of grate plate differs from existing grate plates, whose air outlet direction is vertically upwards: the air outlet direction of the ventilation holes of the oblique-outlet cross-beam grate plate forms a certain angle with the vertical direction. When the grate air leaves the grate plate it has a horizontal velocity, which is beneficial for the horizontal diffusion of the air in the coal bed, strengthens the mixing effect between coal and air, and reduces the phenomenon of coal leaking through the grate.

Scope of application and requirements

Scope of application

The cross-beam grate is a mechanized layer-combustion unit with a compact structure. The cross-beam grate is suitable for boilers with an evaporation capacity of 20~40 t/h and above. Its main structural difference from the chain-belt grate lies in the use of many rigid cross-beams. The grate plates are installed in the corresponding grooves of the cross-beams, and the cross-beams are fixed on the drive chains. There are generally two drive chains (several may be installed when the grate is very wide), driven by the sprockets mounted on the front shaft (driving shaft).

It is widely used in various large boilers and in special equipment such as heating and drying units. It is suitable for burning bituminous coal, lignite and peat; specially designed incineration equipment can also burn other fuels such as bagasse and various types of waste.

Use requirements

The medium used by this grate shall meet the following requirements:

(1) The maximum particle size of the coal shall not exceed 40mm, of which the content of 05mm coal fines shall not exceed 50%, and the content of 030mm coal fines shall be less than 25%.

(2) The moisture content of the coal is less than 20%, with 8~12% being the best.

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

(4) The ash melting point temperature of the coal shall be higher than 1250℃.

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

(6) The net calorific value of the coal shall be higher than 4350kcal/kg.

(7) If the above medium requirements conflict with the medium requirements of the coal feeding equipment, the highest requirement shall be adopted.

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

Structure and characteristics

The whole grate consists of the following parts: (1) support; (2) furnace chain; (3) ash discharge device; (4) side seal; (5) air inlet pipe; (6) rear guide block; (7) front air baffle device; (8) shaft assembly; (9) coal hopper assembly.

(1) The support consists of left and right wall plates and front, middle and rear cross-beams. Several relatively closed large-capacity air chambers are formed between the cross-beams, the ash discharge device and the air chamber partitions; in this way the air volume of each zone on the grate surface can be adjusted, so that the fuel is fully burnt.

(2) The chain consists of links passing through rollers, intermediate guide blocks, chain shafts, retaining rings and pin shafts. Bolt slots are cast on the links, and the cross-beams are fixed with bolts.

(3) One end of the grate is driven by the driving shaft and needs no driven shaft, and the other end is fitted with a guide device; the transition of the chain between the upper guide rail and the lower guide rail is completed by the driving shaft and the guide device. The torque of the driving shaft is supplied by the grate reducer through a coupling.

(4) The side seal is a horizontal right-angle flow-channel type side seal; together with the grate plate side seal, the two sealing lines improve the safety and reliability of operation.

(5) The ash discharge device is of the push-pull type; push or pull the handle of the ash discharge door to open the door, and the fine ash and coal fines collected in the air chamber can be discharged.

(6) The layered coal feeding device is widely used in the coal hopper device; the coal entering the furnace is loose and layered and burns fully, which improves the thermal efficiency of the boiler.

(7) The grate has a compact structure and a reasonable layout; the grate chain moves inside sealed guide rails, is not exposed to high temperature and only bears the movement tension of the grate; the grate made of heat-resistant material contacts the high-temperature burning coal bed on the cross-beams and bears no stress when heated, thus extending the service life of the grate.

(8) The grate has no rear shaft and no eagle iron, which reduces the failure rate of the rear part of the grate during operation and improves the operating efficiency.

(9) The grate chain runs in a tensioned state, without arching and without chain climbing; the chain movement is rolling friction, so the running torque requirement is low and the noise is low.

(10) The grate has good overall sealing and can prevent air leakage and cross-flow between air chambers. The air volume of each air chamber can be adjusted separately, which is convenient and practical.

(11) The grate surface is flat, and the grate plates overlap each other and are arranged closely, which prevents coal leakage and coal dropping; the grate plates can be replaced conveniently without stopping the boiler.

Model parameters

Operating features

1. The structure has good rigidity; the grate plates are not heated, and the cross-beams and chains are not heated either, so the grate is safer and more durable;

2. The grate has a large effective area and low resistance, and the air volume is evenly distributed;

3. The chain movement is rolling friction, so the running torque requirement is low and the friction noise is low;

4. The grate has good overall sealing and can prevent air leakage and cross-flow between air chambers; the air volume of each air chamber can be adjusted separately, which is convenient and practical;

5. The grate surface is flat, and the grate blocks overlap each other and are arranged closely, so coal is not easily leaked or dropped, and the grate plates can be replaced conveniently without stopping the boiler;

6. The ventilation cross-sectional area of the grate is large, generally up to 10%-17%, and combustion is extremely complete;

7. The grate has no rear shaft and no eagle iron, so the rear part of the grate is unlikely to fail inside the furnace.