A large amount of steam is used in the drying, calendering, vulcanization and other processes in the rubber production process. A special rubber and plastic company in the Philippines is one of the most professional industrial rubber plate production bases in the country. It produces rubber products such as special rubber plate, industrial rubber plate, anti-skid fitness series, water gate rubber sealing series, etc., with complete specifications and more than 10000 varieties. This time, the company is particularly cautious in the purchase of boilers, especially in the efficiency of steam provided by boilers. The company has put forward very strict requirements. Sitong boiler manufactures a 4-ton DZL series coal fired steam boiler for it. This series of boilers belong to the horizontal three-way water fire tube chain grate boiler, which can use medium bituminous coal and anthracite. The threaded smoke pipe is also an efficient heat transfer element researched by Sitong boiler for many years, and the heat transfer coefficient is 1.8 times higher than that of ordinary smoke pipe.