YGL Type of Vertical Fixed Grate Coal-fired Thermal oil Heater• Simple structure, low cost.• Adoption of top-mounted tube structure with large heat absorption area, high heat efficiency, never be collapsed.• Heat transfer oiI enters into the boiler from the top and drains out from the bottom, which cannot easily be coked, with long service life of boiler.• Remove ash once a month when burning Shenmu soft coal block for the product. Otherwise, ash may easily be deposited with bad heat transfer.