Protective sealing door disposed on the outermost side entrance, and a shock wave having a barrier agent isolated two functions. Protection should be able to block the closed doors closed doors shock protection, resistance to meet the appropriate requirements. HM the selection of protective closed doors, should not only meet the needs of the hole size, but also to meet the requirements of the design pressure. Although the higher prices of steel doors, anti-nuclear radiation early performance is poor, but because of its lighter weight, hoist flexible, it is usually used in relatively large size of the vehicle entrance. Steel protective closed doors by the hole at whether the threshold is divided, with a fixed threshold, live landing threshold and doors three. ⑴ fixed threshold range air defense doors with protective, reliable, low cost and other advantages, but one hole at a fixed threshold of 150mm high, generally used for personnel access usually small doorway (eg canisters room door). ⑵ cost of living higher threshold range air defense of the door, which closed the door sill installation of steel protection during battle, wartime to meet the appropriate protective, sealed and other requirements; usually no threshold at the doorway to facilitate personnel, vehicles that are also in line with Fire evacuation request, suitable for use in peacetime personnel, vehicles entering and leaving more openings. ⑶ landing doors type series air defense doors can lift, the doors in the promotion states, the next leaf is slightly higher than the ground plane along HFM protective closed doors, the doors can be opened. Openings at no threshold, but need to set up the outside of the threshold can be placed at the doors has a trench. To ensure the maximum protection when the doors closed and sealed request, first landed at the threshold of the doors outside the trench and then, and then lock the doors locked. Such doors peacetime, wartime have no threshold. When the doors opened, the waste above ground level and covered with flush cover, traffic officers, the vehicle is very convenient. Institutions such doors is more complex, high cost, generally used for high-grade basement vehicle entrance. HFM protective closed doors, protective closed doors, Jin Sheng protective closed doors at reasonable prices provided by Henan Sheng-chun, air defense equipment Limited. Henan Jin Sheng air defense equipment Limited (www.jsrenfang.com/) strong, credible, in Zhumadian other industry has accumulated a large number of loyal customers. The company better work attitude and constantly improving innovative ideas will lead Jin Sheng air defense and you hand into the brilliant, for a better future!