Heat insulation treatment of ventilation pipe
A. heat insulation of ventilation pipes and components
① determine the number of heat insulation fixing nails according to the section size and position of the ventilation pipe.
② after fixing the nail position, first wipe the dust and oil dirt on the wall of the ventilation pipe, then apply the adhesive on the wall of the ventilation pipe and the bonding surface of the insulation nail respectively, and then bond them together later. After the fixing nails are firmly adhered, they shall be covered with thermal insulation materials after 12-24 hours.
③ the cutting of thermal insulation material shall be accurate, the cutting surface shall be flat and flush, and there shall be no gap at the lap joint. The longitudinal and transverse joints shall be staggered, and small pieces of materials shall be used as far as possible in the middle part of the upper plane of the ventilation pipe.
④ for the heat insulation of the exposed rectangular ventilation pipe, the galvanized steel wrap angle shall be added at the four corners, and the galvanized iron wire shall be used for fixing or clamping.
⑤ when wrapping glass fiber cloth protective layer outside the thermal insulation layer, first cut the glass fiber cloth into a strip with a width of 200-400mm according to the size of the cross-section of the ventilation pipe, and roll it into a small roll for standby. According to the size and diameter of the cross-section of the ventilation pipe, the glass cloth with different width can also be selected. When winding, first fix the end with "Π" iron nail, and then tighten the glass cloth for winding. While winding and leveling, there shall be no wrinkling, flanging and other phenomena. The lap width of the lap joint between the ring and the two sides of the ring shall be generally 30 ~ 50mm. The end must be fixed with Π shaped iron nails, otherwise it is easy to loosen and fall off.
⑥ one or two layers of fireproof coating shall be applied on the outer surface of glass cloth according to the design requirements, and the coating shall be tight and uniform.
⑦ a layer of galvanized steel plate or aluminum plate shall be added to the outdoor exposed ventilation pipe outside the insulation layer as the protective shell. The lap joint between the shells shall be fixed by riveting, and the lap joint shall be sealed by sealant.
B. refrigeration and heating pipeline insulation works
(1) polystyrene foam shell insulation structure.
A. firstly, the insulation tile shall be buckled on the surface of the pipeline, bound firmly with φ 1.2mm galvanized iron wire every 300 ~ 350mm (the broken end of the iron wire must be embedded in the insulation tile), and the gap between the tile and the tile shall be filled and leveled with asbestos diatomite.
B. the insulation tile shall be wrapped with a plastic film and a glass cloth. When binding, the glass fiber cloth shall be cut into a width of 200-300 mm, and the width of winding and overlapping shall be 50-80 mm.
C. apply two coats of ready mixed paint on the glass cloth.
② felt material insulation structure.
A. the outer part of the pipeline shall be bound with insulating felt, and the overlapping edge shall be tightly attached during binding. The insulation layer shall be bound with φ 1.2mm galvanized iron wire every 300 ~ 350mm. After the first layer is wrapped, the second layer is wrapped. The number of layers depends on the required thickness. The multi-layer binding shall be staggered, filled and sealed strictly.
B. the thermal insulation layer shall be wrapped with a layer of asphalt felt, and the joints shall be tightly overlapped and bound with φ 1.2mm galvanized iron wire.
C. wrap the linoleum with glass fiber cloth, cut the glass fiber cloth into a width of 200-300 mm, and wrap the overlapping width of 50-80 mm. The external surface shall be painted with two coats of mixed paint.
③ heat insulation method of pipe support, hanger and bracket.
A. the wood blocks used for the support, lifting and bracket of the pipeline shall be impregnated with asphalt for corrosion prevention and processed according to the pipe diameter.
B. the supports, hangers and brackets that directly contact with the pipeline must be insulated, and the length of the insulation layer shall not be less than 4 times of the thickness of the insulation layer, otherwise it shall be laid on the skid.
④ the length of bolts plus 25 mm clearance shall be reserved on both sides of the heat insulation of valves, flanges and other removable parts on the pipeline. The valve and flange shall be insulated separately.