Various types of needle type selection principle of the valve

1, low temperature medium pipeline system and device, appropriate chooses with the valve cover type needle valve at low temperature. 2, refining unit of catalytic cracking unit of piping system, can choose lifting lever type needle valve. 3, chemical system in acid and alkali corrosive medium, such as equipment and piping system, appropriate chooses austenitic stainless steel, teflon for valve seat seal type stainless steel needle valve. 4, metallurgy system, power system, petrochemical plant, city heating system in high temperature medium pipeline system or device, can choose a metal to metal seal type needle valve. 5, the need for flow control, can choose the worm gear and worm drive, pneumatic or electric type with v-shaped opening adjust needle valve. 6, oil, natural gas transportation director line, need cleaning the pipeline, and to be buried in the ground, with full size, full welded structure type needle valve; Buried in the ground, choose the full size of welding connection or flange connection of ball valve gate. 7, product oil pipeline and storage equipment, selects the flange connection type needle valve. 8, city gas and natural gas pipelines, selection of flange connection and internal thread connection type needle valve. 9, metallurgy system oxygen in the pipeline system, appropriate chooses strict degreasing process, flange connection type needle valve. As otherwise required or change to the following, should be in order to illustrate: 1. The valve door specifications ( Ins in the valve door class system; Mm in metric valve door) 2. Pressure levels or nominal pressure 3. Flange connection size and sealing surface form 4. Welding and its pore size 5. Threaded end of socket and size 6. Structure length of seven. 8 refractory, antistatic device. Need worm gear transmission, pneumatic or electric 9. Need to lock structure, whether you will lock 10. Materials ( Including the main body, the valve rod, fasteners, etc. ) 11. Gasket 12. Packing 13. Sealing surface material matching ( Sphere sealing surface and the valve seat sealing surface)