Polyurethane foam has good mechanical properties and thermal insulation properties. It can withstand 120°C under normal conditions. It can withstand 180°C by modifying or combining with other insulation materials.
The SSAW steel pipe has a strong thermal insulation property, which can ensure that the temperature of the internal transport material is not changed by the outside world and has good cold resistance in winter. The soundproofing performance of the SSAW steel pipe is very good, to avoid the sound of liquid flowing in the pipe during transportation.
At the same time, the spiral tube can be preserved and does not absorb water, so that the installation position of the pipeline is not limited and can be used at various
locations. Spiral pipe construction is simple and efficient, high efficiency, reduce capital costs. Spiral tubes are used for low heat loss and can save energy.
According to calculations by related departments, dual-control heat supply pipes can generally be reduced by 25% of the construction cost (using FRP as a protective layer)
and 10% (using high-density polyethylene as a protective layer).
Spiral tube thermal conductivity: λ = 0.013-0.03kcal/mhoC, much lower than other commonly used pipe insulation materials, insulation effect increased by 4 to 9 times.
In addition, its water absorption is very low, about 0.2 kg/m2. The reason for the low water absorption is that the closed cell ratio of the polyurethane foam is as high
as about 92%. The low thermal conductivity and low water absorption, coupled with insulation layers and high-density polyethylene or FRP shells with good water-repellent
properties, have changed the status of the traditional trench laying heating pipe “wet cotton padded jacket”, which greatly reduced the number of heating pipes. The
overall heat loss, thermal network heat loss is 2%, less than the international standard of 10%.
Insulation large diameter spiral pipe structure:
(1) Core pipe: Working steel pipe for steam delivery.
Core tube material properties, outer diameter dimensions, dimensional tolerances, and minimum wall thickness are in compliance with the relevant national or industry
standards. The surface of the core tube removes rust, grease, moisture, and other contaminants.
(2) Protection cushion: The sandwich between the core tube and the insulation layer to prevent the inorganic insulation from being damaged due to displacement of the core
tube. When the core pipe is made of spiral welded steel pipe and the inorganic insulation layer is a hard material, a protective cushion layer is provided. The protective
cushion is generally made of aluminum silicate felt, density ≤ 192kg/m3, room temperature thermal conductivity ≤ 0.056w/(mk), and heating line shrinkage ≤ 4%.
(3) Organic insulation layer: insulation layer made of organic insulation material. Polyurethane rigid foam, density 55-65kg/m3, compressive strength ≥ 0.2MPa, normal
temperature thermal conductivity ≤ 0.027w/(mk), water absorption ≤ 3%, applicable temperature ≤ 140°C.
(4) Insulation layer: Insulation layer made of high temperature resistant inorganic insulation material. Room temperature thermal conductivity ≤ 0.055w (mk) Microporous calcium silicate (density ≤220kg/m3), magnesium silicate, rock wool (density ≥110kg/m3) can be used depending on the structure, and the moisture content of the material is also good Temperature, compressive strength and other indicators can also meet relevant requirements.
(5) Outer protective pipe: An outer protective layer that protects the insulation from groundwater, supports the core pipe, and can withstand a certain pressure. According
to different materials, it is generally divided into steel outer tube, high density polyethylene plastic outer tube, glass fiber reinforced plastic outer tube, composite
outer tube and so on. This product generally uses high-density polyethylene (PE) as the outer protective tube, but in areas with high water levels or surface water, steel
outer protective tubes must be used. Steel outer tube material properties and tolerances are in compliance with relevant national or industry standards. The outer surface of the steel tube is shot blasted.
What are the precautions for storing seamless steel pipes?
1. Choose a suitable venue and warehouse; 2. Reasonable stacking, advanced first; 3. Packaging and protective layers of protective materials; 4. Keep warehouse clean and strengthen material maintenance.
Significance of Proximity Effect on the Production of High-frequency Longitudinal Welded Pipes
In addition to the skin effect, the proximity effect is another feature of current. When alternating currents of equal magnitude and opposite directions pass through two adjacent conductors, the current will flow through the adjacent inner surface layers of the two conductors, and when the two conductors pass When alternating currents of the same size and direction, the current will flow through the outer surface layers of the two conductors. The proximity effect of the current makes the current in the conductors further uneven. It is this unevenness that makes the high-frequency welded pipe(ERW).
Summary of Advantages and Disadvantages of High-Frequency Welded Pipe Forming Methods
Advantages and disadvantages of high-frequency welded pipe forming methods
