Some things that \"should be done\" and \"should not be done\" during polyurethane spraying operations

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Prepare special feeding hoses and spray guns for polyurethane materials. If you must use spraying equipment designed for applying other materials to apply polyurethane, please thoroughly clean the equipment before spraying. Otherwise, you will spend most of your time on spraying tasks cleaning the nozzles. l After the spraying is completed, please clean the spray gun using a cleaning solvent; this solvent should pass through the entire spraying process of the spraying equipment, including the spray gun itself. Flip the nozzle repeatedly to ensure that all residual polyurethane material is cleaned off. Stop the material supply, reduce the gun pressure, and remove the gun tip and gun tip holder. After removing the spray gun nozzle from its holder, place it together in the tank containing the solvent. Remove the spray gun and place it in a tank containing solvent. Place the fluid tube into the bucket of cleaning solvent that you use to clean your spray gun equipment. Either reducing the air pressure or opening the fluid valve can allow the cleaning solvent to flow slowly and continuously through the entire fluid pipe. Continue to use the pump inside the spray gun to draw in the cleaning solvent for 5-10 minutes. Pour some of the cleaning solvent into another bucket; insert the suction hose of the spraying equipment into this bucket of cleaning solvent, but keep the hose inside the original bucket. Continue to use the pump inside the spray gun to draw in the cleaning solvent until the remaining solvent is clean and free of impurities. Clean the filtration system; carefully adjust and open the valve at the bottom of the filtration system to drain the polyurethane residues into a small bucket. Since opening and closing this valve can cause the liquid inside the filtration system to spray out, it is necessary to first reduce the pressure in the system before opening the valve, and then gradually adjust the pressure so that the liquid can flow out slowly and steadily at the valve. When the flowing liquid becomes pure, close the valve. Now, the solvent in the spraying system is clean; place the fluid tube in the same bucket as the suction hose, and let the entire spraying system continue to operate in the spraying cycle for 10–15 minutes, or for a longer period if necessary. If you plan to continue using the spraying equipment for spraying the next day, it is still necessary to keep the clean solvent inside the spraying system; all that needs to be done is to turn off the air supply to the spraying system. If you are not planning to use the spraying equipment for a while, fill it with a filler liquid. This helps prevent the spraying system from freezing during long-term storage.