The outer protective layer is meticulously crafted from high-strength, high-toughness polyethylene material. Utilizing Shandong Donghong Pipe Industry Co., Ltd.'s proprietary polyethylene modification technology, the surface of the polyethylene is polarized. This advanced modification significantly enhances its adhesion performance when coupled with polyurethane, ensuring unmatched durability and reliability for our District Energy Pre-Insulated Steel Pipes.
| Working Steel Pipe Diameter mm |
Outer Sheath Diameter mm |
Minimum thickness of outer sheath mm |
Insulation layer thickness mm |
| 426 |
494-554 |
4.0 |
30-60 |
| 478 |
547-607 |
4.5 |
30-60 |
| 529 |
598-658 |
4.5 |
30-60 |
| 630 |
700-760 |
5.0 |
30-60 |
| 720 |
790-850 |
5.0 |
30-60 |
| 820 |
891-951 |
5.5 |
30-60 |
| 920 |
992-1052 |
6.0 |
30-60 |
| 1020 |
1093-1153 |
6.5 |
30-60 |
| 1120 |
1194-1254 |
7.0 |
30-60 |
| 1220 |
1316-1436 |
8.0 |
40-100 |
| 1420 |
1538-1678 |
9.0 |
50-120 |
| 1620 |
1760-1880 |
10.0 |
60-120 |
| 1820 |
1960-2080 |
10.0 |
60-120 |
| Note: can be customized as customer's needs. |
1. Working steel pipe: Featuring high-quality seamless steel pipe, spiral welded pipe, and straight seam welded pipe. Prior to thermal insulation, the mechanical rust removal must meet or exceed GB/T8923.1 Sa level 2.5.
2. Sleeve pipe: Manufactured using specially modified flame-retardant and anti-static polyethylene resin, processed by a single screw extrusion machine. It boasts excellent impact resistance, robust isolation effects, and superior corrosion resistance.
3. Polyurethane insulation layer: Utilizing advanced flame-retardant polyurethane foam through high-pressure injection, this layer impeccably fills the gap between the casing and the working steel pipe. It offers outstanding insulation with low thermal conductivity, high compression strength, minimal water absorption, and a high closure rate.
1. No need for support, significantly reducing heat loss, and completely eliminating the phenomenon of 'support thermal bridge'.
2. High strength and excellent toughness make it easy to weld and convenient for construction.
3. Featuring low thermal conductivity and exceptional waterproof and corrosion resistance, it can be directly buried in the ground or water.
4. Simple connection options including flange and quick joint connections.
5. With a long service life, it can perform effectively in environments ranging from -20ºC to 120ºC for over 30 years.
Insulation steel pipes are used in liquid and gas transmission pipe insulation projects across a range of sectors, including petroleum, chemical industries, central heating and heating networks, central air-conditioning ventilation systems, and municipal engineering. High-temperature prefabricated direct-buried thermal insulation steel pipes offer exceptional thermal insulation performance, ensuring safety, reliability, and cost-effectiveness in construction.
Shandong Donghong Pipe Industry Co., Ltd. (referred to as: Donghong Co., Ltd., stock code: 603856), headquartered in the historical and culturally rich city of Qufu, China, the hometown of Confucius, stands as a premier engineering pipeline manufacturer, distinguished pipeline engineering service provider, and comprehensive pipeline engineering contractor. Our core expertise spans four pivotal categories of functional and customized pipelines: specialized pipelines for rainwater and sewage diversion, municipal area pipelines, industrial and mining area pipelines, and pipelines for national key engineering projects. By integrating design institutes, financial institutions, port logistics, construction units, and both upstream and downstream enterprises, Donghong has crafted a robust industrial ecosystem. Our unwavering commitment is to revolutionize global pipeline systems, enhancing human life with intelligent pipelines and ensuring the unwavering safety of pipeline transportation.
With a dynamic team of over 200 R&D personnel and an impressive portfolio of more than 100 patents, Donghong leverages national enterprise technology centers, the esteemed national CNAS laboratory, academician expert workstations, and post-doctoral workstations. These premier national technology R&D platforms enable us to delve deeply into the digitalization, informatization, and intelligentization of pipeline engineering, spearheading the advancement of the engineering pipeline industry.
In November 2017, Donghong proudly marked a significant milestone by listing on the main board of Shanghai, becoming the first main board-listed company in China's engineered composite piping system sector.
Unparalleled technical research and development capabilities.
Boasting a national CNAS laboratory, cutting-edge test equipment, and rigorous testing protocols, Donghong collaborates on the development of new products, materials, and innovative connection types. This comprehensive approach ensures the unwavering quality, stability, and reliability of our products.
Donghong has established strategic partnerships with more than 5 5A-level logistics companies, and we have many years of transportation experience. Combining automobile transportation, railway transportation, port and shipping logistics, etc., no matter the heat or cold, no matter the area is remote or harsh, we can provide you with the best service. We have a comprehensive transportation strategy to ensure that every shipment is delivered to the customer site as soon as possible.
1. Does your product meet international standards?
Our products have successfully passed CE, BV, ISO, and WARS certifications, with all metrics exceeding standard requirements. Feel free to specify your required national standard, and we will verify or test it for you.
2. What kind of services do you offer?
As a manufacturing factory, we provide high-quality pipe products, pipe fittings, packaging, and shipping. As a professional consultation company, we offer project consulting advice, pipe system solutions, and design recommendations. Additionally, as an engineering-focused enterprise, we provide pipeline contracting services, pipe repair services, and complimentary maintenance guidance.
3. Do you support OEM/ODM services?
Yes, we offer extensive customization in materials, specifications, logos, packaging, connection methods, and more. Our professional team can also provide tailored solutions for your specific projects, with numerous successful cases to demonstrate our capability.
4. What are your terms of payment?
We accept T/T or L/C at sight.
5. How can you guarantee the quality of your goods?
We warmly invite all customers to visit our company and inspect our goods firsthand. We can also conduct stringent tests as per customer requirements before confirming an order. Additionally, we can dispatch samples for customers to perform their own tests to ensure product quality before the bulk production.
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