Since the birth of PU synthetic materials in the 1930s, PU insulated pipes have been rapidly developed as an excellent thermal insulation material, and their applications have become increasingly widespread. Because of their simple construction and significant energy-saving and anti-corrosion effects, they are widely used in various pipelines for heating, cooling, oil transmission, and steam transmission. Below we Jinan Insulated Pipe Let us look at the precautions when using PU insulated pipe.
1. One must truly understand that direct-buried laying of PU insulated pipes is divided into two methods: compensated direct-buried laying and uncompensated direct-buried laying, in both design and construction. Truly master the working principles, characteristics, and application scenarios of each of the two methods, so that they can be reasonably selected in design and construction can be safe, reliable, and economical.
2. During transport and pipe threading, rough handling, overly thin or hard hooks, and excessive force shall be avoided; otherwise the polyethylene pipe may be broken, scratched, or torn.
3. Pipe wall thickness can be adjusted; wall thickness and color can be produced to customer requirements. Because wall thickness varies, insulation thickness is approximate and shall be calculated based on actual thickness.
4. Bends (deflection angles) in direct-buried pipelines have a great impact on pipeline safety. During pipeline installation, if a temporary bend appears, the pipe stress at the bend location will change, and the design unit needs to recalculate and confirm the stress and take corresponding measures before construction can continue.
5. Keep the signal wires on top for ease of installation and inspection. Align and connect wires of the same color to avoid looping of the signal wires at the joint, which would affect the positioning accuracy of the monitoring system. Before welding the carrier pipe, the continuity and resistance of the signal wires shall be tested; if the signal wires are found to be unqualified, the insulated pipe shall be replaced. If after welding the signal wires are found to be open or broken, the insulated pipe shall be replaced or the signal wires located and repaired. After repair, the sealing of the outer jacket shall be ensured.
6. During winter construction, low ambient temperatures can impair joint foaming quality, so winter work should be avoided whenever possible. If it cannot be avoided, heat the carrier pipe, outer jacket surfaces, and foaming materials before joint insulation foaming.
7. Promptly remove wet insulation materials. During high-temperature operation of the network, residual water in the insulation vaporizes as temperature rises, which can carbonize the insulation and destroy the seal of the joint outer jacket.
8. The overlap length of the outer jacket with the outer jackets of the insulated pipes on both sides shall not be less than 100 mm, to ensure the strength and sealing of the joint outer jacket. Especially for hot-melt welded joints, the fusion-welded area of the outer jacket should completely overlap the outer jackets of the insulated pipes to ensure welding quality and sealing.
9. Joint quality has a crucial impact on the overall quality and service life of the pipe network. If the joint seal cannot be guaranteed, water entering the joint will cause carbonization and failure of the PU insulation material during high-temperature operation, destroying the integral structure of the prefabricated direct-buried insulated pipe system and leading to failure of the entire pipe network. Therefore, 100% airtightness testing must be performed at the joints.
10. Fixed piers and fixed supports must meet design strength and cover-soil thickness, length, and compactness requirements before they can restrain pipe displacement during pressure testing and trial operation.
That concludes the precautions for using PU insulated pipe. We hope it is helpful. For more information, please follow us. Jinan Insulated Pipe
