Polyurethane foaming process
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發(fā)布日期：2021-03-24
The steel pipe of the worn outer protective pipe is hoisted to the foaming platform, and the flange plug is used to seal the space between the steel pipe and the outer protective pipe by mechanical hydraulic pressure at both ends. A 200mm long bare pipe is left at both ends of the steel pipe without foaming. After the on-site construction welding and other work are completed, the on-site jointing and foaming will be carried out.
Drill a round hole at the center of the outer protective pipe as the injection hole. When injecting, ensure that the pipe is level and the foam is even.
Debug the perfusion foaming machine, calculate the amount of liquid polyurethane in the polyurethane insulation layer according to the gap and length between the steel pipe and the high-density polyethylene outer protective pipe; determine the mixing ratio of the A and B components according to the heat-resistant temperature requirements of the insulation layer; Determine the foaming time according to the ambient temperature and the amount of infusion, and determine the flow ratio of the A and B components to ensure that the A and B components are fully mixed, atomized, and foamed according to the determined flow ratio and amount within the specified time. Formal construction can only be carried out after the experiment is confirmed.
Install the gun head, insert the discharge pipes of the A and B components into the A and B unions of the spray gun, and connect the compressed air pipe to the compressed air union for trial filling. When the process indicators meet the design technical requirements, formal infusion is performed.
Perfusion, calculate the amount of material according to the thickness of the insulation layer and pipe diameter, adjust the flowmeter, insert the gun head into the perfusion hole of the pipe shell, open the air compressor valve, then open the A and B two-component discharge valves, and press the automatic infusion at the same time The machine is switched on and off, and the equipment is automatically filled and closed.
