Precautions for installation and commissioning of safety valve
(1) the safety valve shall be directly connected with the container body and installed at the highest point of the container. The safety valve on the liquefied gas storage tank shall be installed in the gas phase space, and the safety valve for the liquid shall be installed below the normal liquid level, and the nominal diameter of the safety valve inlet pipe shall not be less than 15mm.When it is difficult to be mounted on the container body due to special reasons, it can be considered to be installed on the outlet pipe road. However, the pipeline between the installation of the safety valve and the container should avoid sudden turning, partial contraction of the section and other structures, and prevent the increase of pipeline resistance and the blockage of dirt accumulation.
(2) no matter where the safety valve is installed, the cross-sectional area of the connecting pipe and pipe fitting through hole between the container and the safety valve shall be less than the inlet area of the safety valve.If several safety valves are installed at a joint, the area of the joint shall be at least equal to the total area of the inlet of several valves, preferably 1.25 times the total.
(3) in the middle of the container and generally prohibits installed between the relief valve shutoff valve, but for flammable, toxic, or larger viscous medium containers, to facilitate the relief valve replacement, cleaning, can be in containers and loading cut-off valve between the relief valve, but the cut-off valve shall not hinder the safety valve structure and size of the size of normal discharge, when the normal work of the container, the cut-off valve must be in the fully open position and seal.
(4) if there is any possibility of condensing liquid in the discharge pipe after the safety valve, automatic elimination facilities shall be considered;The inner diameter of the closed relief valve outlet pipe shall not be less than the nominal diameter of the outlet pipe of the safety valve.The discharge pipe shall, in principle, be one valve per valve and no valve shall be installed on the discharge pipe. When two or more relief valves share the same discharge pipe, the cut-off area of the discharge pipe shall not be less than the total cut-off area of all relief valve outlet pipes.A common exhaust pipe may not be used for combustible gases such as oxygen or other gases that can react chemically when mixed.
(5) before installation, the new safety valve shall adjust its opening pressure and return seat pressure on the test bench and check the sealing of the closing parts.The opening pressure can be achieved by adjusting the load applied to the disc, such as the weight or position of the weight of the lever relief valve, the position of the spring nut on which the spring is pressed by the spring relief valve (based on the correct selection of the spring pressure level), and the force of the return seat can be achieved by adjusting the position of the upper and lower adjustment rings of the relief valve.
Use and management of the safety valve
Properly selected and properly installed safety valves should also be properly used and managed to function.In everyday use, in order to ensure the good condition of the relief valve, should strengthen the maintenance and inspection, keep body clean, prevent the valve body and spring rust, prevent the body by oil dirties, foreign bodies, jams, often should check valve seal is in good condition, to prevent the heavy hammer loose or lever type relief valve is moved, spring safety valve adjusting nut is randomly budge, leak detection should be timely replacement or repair, ban with increasing load (such as excessively tight spring safety valve adjusting nut, or on the lever of safety valve lever is aggravating, etc.) of the method to eliminate leakage.In order to prevent the disc and seat from being stuck by dirt such as grease in the gas, the safety valve used for air, water vapor or other gases with more viscous dirt but no environmental pollution when discharged shall be periodically pulled by the wrench to carry out inlet and outlet to flush out the dirt.
The safety valve shall be inspected regularly, including opening pressure, return seat pressure, sealing degree, etc., and the requirements shall be the same as the debugging of the safety valve.When the inspection is unqualified, it should be disassembled, and the parts should be inspected in detail for cracks, scars, abrasion, corrosion, deformation, etc., and then repaired or replaced before assembly inspection.The periodic inspection period of the safety valve may be the same as that of the vessel used.