What preparations should be made before installation of stainless steel welded air duct?

Preparation before installation of stainless steel welded air duct for environmental protection project in painting workshop

Before installation, the preparation of stainless steel welded air duct focuses on site review, material verification, instrument preparation and safety disclosure, which meets the sealing and anti-corrosion requirements of waste gas treatment in painting workshop, while avoiding site construction interference and ensuring installation accuracy and efficiency. All the preparation work is centered on "accurate matching of prefabricated air duct with site working conditions, compliance and safety in the whole construction process", which is divided into six modules, which are simple and suitable for site operation:

A, site survey and size review

Check the axis, elevation and direction of on-site air duct installation according to the construction drawings, especially confirm the distance between air duct and wall, beam and column, production equipment and running track, reserve a maintenance space of ≥500mm, and avoid the operation positions of core devices such as paint mist treatment equipment and fans in the painting workshop;

Measure the strength of the wall/beam column at the installation point of the air duct hanger, confirm that the bearing capacity matches the weight of the air duct, and mark the fixing position of the embedded parts/expansion bolts;

Check the size, hole position and center height of the butt flange between the air duct and the environmental protection equipment (activated carbon adsorption box, paint mist processor and fan) to ensure that the prefabricated air duct and the equipment interface are accurately matched with a deviation of ≤2mm.

Second, the prefabricated duct and accessories in check

Count the fittings such as air ducts, flanges, elbows, tees and reducers according to the prefabricated numbers, and check that the quantity and specifications are consistent with the drawings, and there are no missing parts or wrong parts;

Visual inspection: the surface of the air duct is free from deformation, scratches and depressions, the roundness/straightness deviation meets the requirements, and the weld is free from slag inclusion, air holes and cracks, and the pickling passivation treatment is completed; Flange surface is flat and free from warping, bolt holes are evenly distributed, and the hole spacing deviation is ≤ 2mm;

Initial inspection of sealing performance: randomly sample prefabricated air ducts, and check the sealing performance of welds with soap solution method. If there is no bubble, it is qualified, so as to avoid unqualified air ducts from being brought into the site;

Fitting classification: classify and stack the air ducts and fittings in the same area and direction, and mark them with numbers to prevent confusion on site.

Third, the preparation and pretreatment of supports and hangers and auxiliary materials

Support and hanger: make stainless steel support and hanger of the same material according to the design requirements (to avoid electrochemical corrosion caused by contact of different materials), check the welding firmness, and the surface is free of burrs and welding slag, and complete rust removal and cleaning; Cut and punch holes in advance according to the on-site spacing to protect the finished products;

Sealing auxiliary materials: prepare oil-resistant and temperature-resistant rubber gasket (suitable for coating waste gas, with a thickness of 3~5mm, without splicing or damage), stainless steel bolt and nut (with flat washer and elastic washer) and sealant (temperature-resistant and corrosion-resistant);

Auxiliary materials for damping: prepare rubber damping pad (used between air duct and bracket) and stainless steel canvas soft joint (used for connecting air duct with environmental protection equipment, with a length of 200~300mm), and check whether the soft joint is damaged or leaked;

Other auxiliary materials: prepare pickling passivation paste, sandpaper, cleaning agent (to clean the oil stain/dust on the installation surface) and antirust paint (for the exposed parts of bolts).

Four, instruments and equipment preparation

Installation tools: torque wrench, adjustable wrench, ring wrench, level gauge, tape measure, wire pendant, Mo Dou (pay-off positioning), electric drill, expansion bolt gun, angle grinder (grinding flange/installation surface);

Protective tools: argon arc welding gun (only used for on-site emergency repair, and the painting workshop should try to avoid on-site welding), welding slag cleaning hammer and wire brush (cleaning weld);

Testing tools: soap solution, watering can (initial site sealing inspection) and anemometer (for later debugging and preparation in advance);

Safety tools: safety helmet, safety belt (for aerial work), non-slip gloves, goggles, warning belt (dividing the construction area);

Auxiliary equipment: aerial work platform/scaffold (used for aerial installation in painting workshop, built and accepted in advance to ensure firmness), chain block (hoisting large-diameter air duct).

V. Preparation of site construction conditions

Site cleaning: clean up the sundries, oil stains and paint residue in the installation area of the air duct, ensure the smooth construction passage, and divide the exclusive material stacking area (away from the painting operation area to prevent paint mist from polluting the air duct);

Working surface treatment: clean the installation position of the support and hanger and the joint surface of the air duct, remove oil stain and dust with cleaning agent, and grind the sealing surface of the flange with an angle grinder until it is smooth to ensure close fitting;

Safety protection: report the hot work in the painting workshop (if emergency welding is needed on site), and equip with fire extinguishers and fire sand; When working high above the ground, build protective railings, set warning belts on the ground, and arrange special care;

Cross-operation coordination: communicate with the production team and equipment operation and maintenance team in the painting workshop, avoid the construction during the peak production period, and prevent the interference of equipment operation vibration and paint mist spraying on the installation work.

VI. Technical and Safety Disclosure

Technical disclosure: the person in charge of construction explains the construction drawings and installation specifications to the installation team (such as "main pipe first, branch pipe first, upper pipe first and lower pipe first"), defines the requirements of elevation, axis, spacing between supports and hangers, and flange butt sealing, and emphasizes the core points of oil prohibition and leakage prevention of air ducts in the painting workshop;

Safety disclosure: emphasize the safety regulations of painting workshop, and prohibit smoking and illegal hot work in the working area; Safety belts must be worn for aerial work, and it is forbidden to overload the scaffold/working platform; When using electric tools, do a good job of leakage protection to avoid contact with painting equipment lines;

Clear division of labor: determine the on-site command, installation, measurement and monitoring personnel, clarify the responsibilities of each post, formulate the construction schedule, and ensure the orderly installation process.

Extra attention (exclusive to painting workshop)

All air ducts, auxiliary materials, tools and instruments entering the painting workshop shall be cleaned of oil and dust on the surface in advance to avoid being brought into the paint fog operation area to cause pollution;

When the prefabricated air ducts are piled up on site, they should be padded with wood squares to avoid direct contact with the ground (to prevent oil pollution and accumulated water from corroding the air ducts on the ground), and should be protected against rain and collision.