Polyurethane foam insulation pipe

DATE：2022/6/10 8:46:39 / READ： / SOURCE：This station

Polyurethane foam insulation pipe

Energy conservation and environmental protection have always been issues of concern to people. At present, the main source of power in China is thermal power generation, and its steam power cycle efficiency is generally less than 50%. In order to make the energy more reasonable and scientific application, the steam of thermal power plants can be led out for urban central heating or plant use, which improves the energy utilization rate and reduces pollution. Due to the requirements of municipal construction, heat supply pipelines are generally directly buried underground. The insulation layer of heat supply pipelines must adopt insulation materials with good heat insulation performance, non moisture absorption, long service life and convenient maintenance. Rigid polyurethane foam is widely used because it meets these conditions. The most commonly used direct buried insulation pipe of modern heat supply pipeline is a three-layer structure, with pressure resistant steel pipe as the inner pipe, rigid polyurethane foam as the middle layer, and high-density polyethylene protective sleeve as the outer sleeve. Antirust paper coating production line www.handern com
The rigid polyurethane foam used for directly buried insulation pipes for urban central heating requires long-term resistance to 100 ℃ and short-term resistance to 130 ℃: the production process of rigid polyurethane foam pipe insulation is divided into manual casting, one-step industrialized continuous production and two-step industrialized continuous production. Antirust paper coating production line www.handern com
① The manual casting process is relatively backward and is now basically eliminated.
② The one-step process is that the steel pipe runs forward on the conveyor belt, the rigid polyurethane foam insulation layer and the high-density polyethylene outer protective layer are formed at the same time, and only the pipes with pipe diameter less than 425mm can be produced.
③ The two-step process is to first produce an outer protective sleeve layer with an extruder according to the required size, which is sleeved outside the steel pipe, and then cast polyurethane composite between the inner and outer pipes for foaming, so as to produce a steel pipe insulation pipe with a diameter of more than 900mm.
The two-step process is mainly used internationally because the quality is easy to guarantee. At present, many domestic enterprises produce directly buried insulation pipes with rigid polyurethane foam as insulation. See table 5-21 for comparison of thermal conductivity between polyurethane foam and other insulation materials. Chinese industrial standard CJ t11-2000 and European standard for polyurethane foam and finished pipe of prefabricated directly buried insulation pipe. Antirust paper coating production line www.handern com
At present, the standards adopted for urban central heating pipelines are the petroleum industry standard sy/t0415-96 "technical standard for rigid polyurethane foam anti-corrosion insulation layer for buried steel pipelines" · 160 "and the Chinese industry standard 20 ° polyurethane foam prefabricated directly buried insulation pipe. The insulation layer of urban central heating pipelines must be made of insulation materials with good heat insulation performance, non moisture absorption, long service life and low maintenance cost. After the rigid polyurethane foam insulation pipe is adopted for the anti-corrosion and insulation of chemical pipelines, the surface temperature of the pipe can be increased by 10~15 ℃, without dew and frost, which greatly reduces the heat loss and improves the thermal efficiency. It can be used as heat pipe insulation or cold storage insulation, and the construction is simple, convenient, safe, short construction period and fast production.
1. main processing methods
The processing methods of rigid polyurethane foam plastic pipe insulation layer are as follows.
The biggest disadvantage of one method is the high loss rate of foamed plastics.
2 semicircular precast units. It is a general and simple method to use semicircular rigid polyurethane foam plastic preform as the preheating layer for the sales channel. A series of prefabricated parts with the same pipe diameter can be processed in batches by preparing several sets of molds according to the standard pipe. When in use, two semicircular polyurethane foams are combined to form a complete insulation sleeve.
③ Spray foaming molding. Spray foaming can be carried out on site. This method is only applicable to pipes with larger diameters. The rigid polyurethane foam plastic raw materials are evenly mixed and sprayed outside the pipe. After foaming, a complete and seamless thermal insulation layer is obtained. This method is not suitable for pipes with small diameter because the raw material consumption is too large during spraying.
④ Continuous forming. Continuous forming of pipe insulation is an advanced processing method. There are many specific production methods of continuous forming, but the basic principles are similar. Antirust paper coating production line www.handern com
The following mainly introduces the continuous forming method of rigid polyurethane foam insulation pipe, which has high production efficiency and accurate product size.
2. raw materials and typical formula
In the typical formula of polyurethane foam insulation pipe produced by continuous forming method, polyether and polyisocyanate are used as basic raw materials, diethylethanolamine and dibutyltin laurate are used as reaction catalysts, silicone oil and fluorochloroform are used as foam stabilizer and foaming agent respectively.

Author：admin

---