First, the main purpose of the shut-off valve pneumatic valve double acting cylinder by the intake chamber or the lower chamber to the intake valve remote control, easy to operate and flexible. Cylinder use medium: compressed air, nitrogen. Simple structure, manufacture and easy maintenance; small working stroke, closing time is short; closing body (valve) seat sealing surface with cone seal, small closing force, erosion resistance, reliable seal. Seat may be replaceable seat, it can be any combination of closed counterpart sealing surface material to meet the conditions required to extend the service life. Second, the pneumatic shutoff valve structure features 1, selected materials, in line with domestic and foreign standards, reasonable structure, beautiful shape. 2, the valve seat sealing surface using iron-based alloy or Stellite (Stellite) cobalt-based alloy cladding made of wear-resistant, high temperature, corrosion, anti-abrasion performance, long life . 3, stem quenched and the nitrogen treatment, with good corrosion resistance and scratch resistance. 4, can be a variety of standard pipe flanges and flange sealing surface types to meet various project needs and user requirements. 5, the full range of body materials, packing, gaskets, according to the actual working conditions or user requirements reasonable matching can be applied to all kinds of pressure, temperature and medium conditions. 6, inverted sealed with screw connection seal seat or body made of austenitic stainless steel welding, reliable sealing, replace the packing can be carried out without stopping the machine, convenient, does not affect system operation. Third, the pneumatic shutoff valve application specification design and manufacture GB / T12235 connecting terminal size structure length GB / T12221 flange dimensions JB / T79 inspection and testing JB / T9092 Material Carbon Steel GB / T12229 stainless steel GB / T12230 alloy Q / ZB66 mark GB / T12220 Delivery JB / T7928 four main parts and materials pneumatic shut-off valve and the valve bonnet main purpose valve stem packing seals Medium Temperature (≤ ℃) WCB WCB + D507MO D577 2Crl3 flexible graphite water, oil, Steam 425 ZGlCrl8Ni9Ti 0Crl8Ni9Ti Stellite12 Stellite6 lCrl8Ni9Ti PTFE nitric acid 200 ZGlCrl8Ni2Mo2Ti CF8M Stellite12 lCrl8Ni2Mo2Ti lCrl8Ni2Mo2Ti PTFE phosphoric acids, bases, mixed acid 200 ZG00Crl7Nil4M02 CF3M Stellite12 Stel1ite6 316L PTFE phosphoric acids, urea, ammonium carbamate solution 200 ZGlCr5MO ZGlCr5MO Stellite12 Stel1ite6 25Cr2Mo1VA flexible graphite water, oil products, steam 550 See: http: //www.chuanhuvalve.com/ddjzf/qdjzf-j641h.asp