Brief：DZL series package chain grate boiler, combustion equipment was chain grate. Main engine is single drum longitudinal arrangement, inside of drum was a single-pass thread smoke tube ,left and right sides of the hearth is equipped with bare water wall tube, part of riser pipe formed the furnace top, refractory brick Hanging at the bottom of the drum don't accept high temperature flame radiation, drum on both sides of the lower part has two symmetrical convective pass ,water wall cured tube was assembled at 750 mm from the center line of the drum a, to avoid tearing weld joint.