In oil and gas equipment, valve using mostly have the characteristics of inflammable, explosive, media and complex process, process conditions, long construction period, once the valve failure in production, light person leading to medium leakage, environmental pollution, the person that weigh cause fire and explosion, caused by malignant accident loss brings to the nation and the people's life safety, So the oil and gas production of the valve quality requirements are high. Its main functions are: connect and truncate the medium; Prevent medium flow back; Adjust the medium pressure, flow; To prevent the medium pressure exceeding the specified value, to ensure the safe operation of the pipeline or equipment.
