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1. The design of the body of the relief valve for the drain hole should aim to minimize the effects of medium deposition and fouling. Safety valves used for steam and liquids shall be provided with a drain hole at the lowest point where liquid collects, below the valve seat sealing surface. For safety valves with a nominal diameter greater than 65 mm, the diameter of their discharge orifice shall be not less than 9.5 mm ； For safety valves with a nominal diameter of 65 mm or less, the diameter of their discharge hole must be at least 6.5 mm. Clause 4.4.5 of GB/T 12243-2021 \"Safety valves with direct spring loading\" also stipulates that, in order to prevent the accumulation of liquid, drain bolt holes shall be provided at locations below the valve seat sealing surface. When installing safety valves for steam and liquids, it is necessary to ensure that no fluid accumulates on the downstream side of the safety valve, as this will affect its performance and cause erosion of the spring and internal components. Many safety valves are equipped with a drain connection hole on their body; if this drain outlet is not used in practice, or if such a hole is not present on the safety valve, a weep hole should be installed on the pipe as close as possible to the outlet of the safety valve. 2. Vent hole: For bellows-type safety valves, a vent hole must be provided in the valve cover to ensure that the interior of the bellows is in communication with the atmosphere. In cases where the medium is flammable or corrosive, this vent hole should be connected via a pipe to a safe area, thereby preventing any hazards caused by the leakage of the medium following damage to the bellows. Upon manufacture, balanced bellows safety valves are equipped with temporary dust-proof plastic plugs on their vent holes. During normal operation, these plugs must be removed; otherwise, pressure may build up inside the valve cover, leading to internal expansion failure of the bellows. If the vent hole is artificially blocked, the same results will occur. Installing a vent elbow with a dust cover can prevent impurities from entering the valve chamber, ensuring the proper operation of the safety valve. Note: When designing, some manufacturers take into account the versatility of valve covers. For relief valve covers of other types, the drain holes should be plugged with threaded plugs to form a closed-type cover; otherwise, medium leakage may occur. 3. Adjustment screw: The adjustment screw for the safety valve is usually located on the top or side of the safety valve; the exact location depends on the model of the safety valve. Typically, arrows indicating the direction of adjustment are marked on the adjustment screw. Tightening the adjustment screw increases the opening pressure of the safety valve; conversely, loosening it decreases that value. To prevent the mechanism for adjusting the compression amount of the spring (such as an adjustment screw) from loosening, as well as to prevent arbitrary changes to the already adjusted setting, the safety valve must be equipped with a anti-loosening device. Note: The external adjustment mechanisms of safety valves should all be equipped with lead-sealing areas (as shown in the figure) so that they can be sealed with lead after successful commissioning. After disassembly, reinstallation, and debugging, the lead seal should be applied again. The seal should be of a type that must be broken in order to make adjustments.