In March 2006,the survey team of China Chemical Equipment ISOC came to our company for checkup of geting certificate. All system’s files which  was about design quality ensured and company’s operating were included. Survey team gave positive judgements ,and awarded the Manufacture License of pressure vessel (Class A1/A2) to Yongsheng in Oct. 2006, which indicated Yongsheng Machinery had the manufacture’s qualification of high pressure vessel (just monolayer), and medium/low pressure vessel of the third kind since that time.