Introduce a double block and bleed valve's structure and working principle.The valve is superior to common gate and ball valves in terms of its sealing performance and service life.The valve has the functions of being fireproof, on-line maintenance, double block and bleed, cavity pressure relief, internal leak detection and others. Illustrate the double block and bleed valve's functions and applications in the oil and gas storage and transportation systems in combination with examples, which has opened new development potential for process design of oil and gas storage and transportation systems and solved many problems encountered in pipeline design. It has not only optimized the pipeline design and improved the product quality but also saved the pipeline operation costs.
