Characteristics： 1、 Design and manufacture of product according to ANSI B16.34 and API 600. 2、 Compact structure,small bulk ,erfectrigidity,safety and reliable. 3、 Blow down part utilize flexible structure, can autoatically compensate distortion of body due to abnormal burden or temperature, so seal credible and preent wedge being blocked. 4、 Manual valve with DN over or equal to NPS10",class 400 pounds and DN over or equal to NPS6",class 600-2500 pound equip with rolling bearing to operate easily. 5、 Material of main body,material of trims, packing,washer, material ,of fastener an logically combine according to customer'srequirement or actual work status. 6、Exchangeable seat,random combine the material of surface of blow down part to meet the requirement of work status,porlong service life.