What details should be paid attention to in the installation of stainless steel welded ventilation pipes?

The core of stainless steel welded ventilation pipe installation is to ensure no leakage and smooth air flow, while giving consideration to structural stability and corrosion resistance. The key details focus on interface treatment, installation accuracy and protective measures.

Prepare details before installation

Inspection of pipes and fittings: make sure that the materials of pipes, elbows, flanges and other fittings are consistent, the surface is free of scratches, corrosion and deformation, and the wall thickness meets the design requirements.

Site cleaning: the installation area should be dry and clean to avoid dust and oil pollution on the inner wall of the pipeline, which will affect the ventilation effect or lead to corrosion.

Preparation of tools and accessories: use stainless steel special welding tools, gaskets (compatible with stainless steel materials, such as fluororubber pads), and use stainless steel for bolts to avoid contact corrosion of dissimilar metals.

Key details of interface connection

Welding interface treatment: before the pipeline butt joint, it is necessary to polish the groove and remove the oxide scale, and the butt joint clearance should be controlled at 2-4mm to avoid the wrong edge exceeding the standard.

Quality control of welding seam: argon arc welding or mixed gas shielded welding shall be used during welding, and the welding seam shall be continuous and full, free of air holes and slag inclusion. After welding, the welding slag shall be cleaned in time and the sealing performance shall be checked.

Flange connection requirements: the gasket should be laid flat, and the bolts should be fastened evenly to avoid sealing failure caused by uneven local stress, and the exposed thread length of the bolts should be consistent (2-3 threads).

Installation accuracy control details

Direction and slope of the pipeline: control the levelness and verticality according to the design drawings, and the slope deviation of the horizontal pipeline shall not exceed 3‰ to avoid water accumulation and dust accumulation.

Installation of supports and hangers: The spacing between supports and hangers shall be determined according to the pipe diameter (DN≤500mm ≤3m, DN>500mm ≤2.5m), and rubber pads shall be added at the contact point with the pipeline to prevent the pipe wall from being scratched.

Elbow and reducing treatment: the elbow should be installed to ensure smooth airflow direction, and the reducing pipe should be concentric to avoid sudden contraction and expansion leading to airflow vortex.

Protection and subsequent treatment details

Anti-corrosion measures: avoid direct contact between pipelines and dissimilar metals such as carbon steel during installation, and add isolation pads when necessary; Outdoor installation needs to be rainproof and sun-proof, and the interface should be additionally sealed and protected.

Inner wall cleaning: after installation, use compressed air to purge the inner wall of the pipeline, remove impurities and welding slag, and ensure smooth air flow channel.

Commissioning test: air tightness test shall be conducted before the ventilation system is started, and the joints and welds shall be smeared with soapy water, and it is qualified if there is no air bubble leakage; Monitor noise and vibration during operation, and adjust the position of supports and hangers in time.