Bellows gate valves are forced sealing valves, so when the valve is closed, pressure must be applied to the disc to force the sealing surface not to leak. When the medium enters the valve body from below the disc, the resistance to be overcome by the operation force is the friction force of the stem and packing and the thrust generated by the pressure of the medium. The force of closing the valve is greater than the force of opening the valve, so the diameter of the valve stem is large, otherwise the fault of the stem top bend will occur.
Oil and non-corrosive gas line for opening and closing device, Especially suitable for steam engine vacuum condensation system of thermal power plant, water seal gate valve: pressure is PN16~PN160,150LB-900LB steel globe valve is suitable for pressure 1.6~25MPa/2.0-15.0MPa operating temperature -29~+550℃ Petroleum, chemical, pharmaceutical, chemical fertilizer, electric power industry and other conditions of the pipeline, the applicable medium for water, oil, steam, acid medium. The material is usually: cast steel WCB, stainless steel CF8(M),CF3(M). Forged steel has A105,F304(L),F316L and so on.
Pneumatic valve procurement only clear specifications, categories, pressure to meet the procurement requirements of the practice, in the current market economic environment is not perfect. Because the pneumatic valve manufacturers for product competition, each in the pneumatic valve unified design idea, different innovation, formed their own enterprise standards and product personality. Therefore, it is very necessary to put forward the technical requirements in detail when purchasing pneumatic valves, and coordinate with manufacturers to obtain consensus, as the annex of the pneumatic valve procurement contract.