1, according to the heating points: Portrait heated graphite tube, transversely heated graphite tube 2, according to the performance points: Ordinary graphite tube (non-pyrolysis) suitable for low temperature (≤2000 ℃) atomic elements such as silver, cadmium, lead; pyrolysis graphite tube for low, medium and high temperature (> 2500 ℃) atomic elements; platform graphite tube suitable for medium and low temperature (≤2400 ℃) atomic elements. By conventional production process of producing graphite carbon blocks using ordinary carbon production process can be made porous carbon and porous graphite block graphite, except that carbon graphite pore forming agent is added in the ingredients, or pore forming agent volatilized during firing and graphitization decomposed pores. Commonly used porogen sodium chloride graphite emulsion, sodium fluoride, sawdust, etc., controlling the addition amount of a pore-forming agent and a pore forming agent is added in particle size, can substantially control porous carbon and porous graphite porosity and pore size. Carbon graphite, the North Sea Dragon Carbon and graphite by Carbon Co., Ltd. Weifang Sea Dragon. Carbon Co., Ltd. Weifang Sea Dragon (www.longmentanye.com) Shandong Weifang, graphite and carbon products leader, over the years, the company is implementing the scientific management, innovation and development, the principle of honesty and trustworthiness, and satisfy customer needs. In the North Sea Dragon carbon industry leadership with the staff warmly welcome all inquiries negotiations to create the North Sea Dragon carbon industry a better future.