Double Drum Water Tube Chain grate boiler

Double Drum Water Tube Chain grate boiler

SZL series chain grate boiler is the national patent products of Zhongding Boiler, the patent No. is ZL 2009 2 0089355.7. The traveling grate boiler is horizontal type double drums boiler with high steam quality, the combustion equipment is traveling grate, has the advantages of high automatic degree, high temperature resistances and low fuel leakage. Zhongding boiler takes several breakthroughs on boiler design, such as membrane water cooling wall, low thermal inertia design, and water cooling combustion chamber. The convection heating area increase more than 50%, and by using the light furnace wall, the thermal inertia decrease 70%, to improve thermal efficiency. SZL series traveling grate water tube boiler has the advantages of compact structure, high thermal efficiency, high steam quality, sufficient output, and convenient operation.

Rated Capacity:



<2.5 Mpa




Rice husk, wood chips, bagasse, straw, and other biomass fuels.

Boilers Structure

Double Drum Water Tube Chain grate boiler

1. The boiler boiler adopts membrane water cooling wall structurer, the boiler is full sealing, reduce heat loss, improve boiler efficiency.

2. Whole membrane water cooling combustion chamber and inverted "α" arch furnace technology achieve high combustion efficiency, high output.

3. Extended length of the grate, extended the coal burning time, improved the boiler thermal efficiency.

4. Light furnace wall structure reduce heating loss, thermal inertia decrease 70%, furnace heat up fast, boiler start-up and shut down quickly.

5. Anti-coking heater design, remove the side sealing steel, avoid the problem of grate stuck and uneven air distribution for combustion.

6. Adopt light rail I-beam for the rail under the grate, abrasion resistance and difficult for deformation, improve the reliability of boiler operation.

Auxiliary equipment



The chain grate is 500~1000mm longer than others, lengthen the fuel combustion time, improve combustion efficiency.



We adopt Siemens PLC and Schneider electrical components. can realize automatic interlock control to ensure boiler safe operate.



We adopt aluminum alloy fin tubes, its heating transfer area is 2-10 times larger than the bare tube, has a good heating transfer and mechanical property.



We adopts the stainless vertical pump with low noise, stainless impeller and pump body.

Steam header

Steam header

Standard configuration: one inlet, three outlets, equipped with pressure gauge and thermometer. It can be designed according to customers' requirement.

Water softener

Water softener

It is fully automatic and free debugging. We adopts PE material for salt tank body, it has hard texture and it is easy to move, anti-shock, and no leakage.


Zhongding Boiler pay more attention to the boiler quality from raw material to producing process.

boiler quality
we choose domestic well-known manufacturer who can provide component report of raw material, to ensure the raw material is qualified. After the completion of raw material procurement, there are specialized technicians in our factory to make sampling chemical composition analysis and physical performance analysis, and we can also provide raw materials inspection report.
We adopt numerical control cutting, which has the advantage of high precision, neat cutting surface, nice appearance and high material utilization.
Boiler manufacturing
Boiler production
We adopt submerged arc fully automatic welding. When each welding process is done, the 100% X-ray inspection will be arranged for every welding seam, which can prevent the defective parts from flowing into the next process.


Model Steam Capacity (t/h) Working Pressure (MPa) Thermal Efficiency (%) Body Heating Area (m2) Overall Dimension
L×W×H (m)
Weight (t)
SZL4-1.20/1.6/2.5-T 4 1.25/1.6/2.5 81 99.5 7.46×2.65×3.52 32
SZL6-1.20/1.6/2.5-T 6 1.25/1.6/2.5 81 134 7×2.7×3.5 21
SZL10-1.20/1.6/2.5-T 10 1.25/1.6/2.5 81 233.6 7.89×3.26×3.53 28
SZL15-1.20/1.6/2.5-T 15 1.25/1.6/2.5 82 310.5 10×3.2×3.5 30
SZL20-1.20/1.6/2.5-T 20 1.25/1.6/2.5 82 478 11×3.2×3.5 35
Note: 1. Parameter is for reference only, if any changes should follow the factory technical data.
2. Our company can design boiler products based on customers’ requirement and different biomass pellet fuels.


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