If there is a large difference in diameter between the safety valve and the inlet and outlet pipes, can the diameters of these pipes be changed without replacing the safety valve?
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Currently, the pipes at the inlet and outlet are DN15, but the safety valve is DN65. Is it possible to adjust the diameter of the pipes in stages to make them compatible with the safety valve? As shown in the figure?
No. \"Installation and Selection of Safety Valves\" (HG/T 20570.2-95) 12.0.1 Safety valves should generally be installed as close as possible to the equipment or pipelines they are meant to protect, and the installation location should facilitate maintenance and inspection. The pipe diameter shall be no smaller than the inlet diameter of the safety valve, and the pressure drop in the inlet pipe shall not exceed 3% of the set pressure (gauge pressure) of the safety valve. 13.0.1 The diameter of the pipe at the outlet of the safety valve shall be no smaller than the outlet diameter of the safety valve. For spring-loaded safety valves, the effect of static back pressure is not taken into account during spring setting; the sum of the dynamic back pressure in the outlet pipeline (calculated as required by 9·0·2) and the static back pressure must not exceed 10% of the set pressure (gauge pressure). For bellows back-pressure balanced safety valves, it should not be greater than 50%
What if the diameter-changing section is far away from the safety valve?
It’s about whether the amount of discharge is sufficient; it’s not a matter of distance. Any change in diameter will inevitably lead to a change in the amount of discharge