PPU shell has a semi-cylindrical shape, heat-insulating purpose and is made of polyurethane foam. It is used as insulation against temperature loss.
This type of insulation is quite widespread in the world, as it has high durability, reduces operating costs and protection against heat leaks. We can say that polyurethane foam pipes are a new round in the development of technology for installing heating systems.
GOSTs of manufacture. Areas of use
Equipment for the production of PPU shells should be located in the factory. Pipes protected by this method comply with GOST 30732-2006 TGI (thermal insulation) and are transported directly to the installation site. There is also a technique for filling already existing networks with polyurethane foam insulation using PPU shells.
Scope of this type of product:
- hot and cold water supply networks;
- heating mains with a boundary temperature of up to 130-150 degrees Celsius;
- in the chemical and petroleum industries, for example for transporting liquefied gas.
Equipment for the manufacture of PPU shell
The heat insulator is made in the process of foaming a multicomponent polymer mixture. Equipment for the production of PPU shells is a mold in the form of two half-cylinders with the same thickness of the insulating layer.
PPU shell, the production of which implies the presence of a whole set of tools, is an environmentally friendly product, does not lose its operational characteristics and does not age over time (the guarantee for the operation of such a pipeline is 30-35 years).
Equipment for the production of PPU shells also includes a mixing machine that mixes the components of the mixture, casting tables with different sizes, configurations and functions.
Used in the development of this product and special tools. They include knives for cutting insulating material, kraft paper, foil insulation, fiberglass and other devices for cutting insulation into pieces.
Before pouring the polyurethane mixture into molds, the materials required by the technology are laid in them. After the end of the polymerization, crystallization and cooling processes of insulation, half-cylinders of a given thickness with concavities and bulges are obtained, which, when folded together, form a heater.
PPU shell sizes
The dimensions of this product, according to the standards, are as follows:
- the thickness of the insulating layer is within 20-60 mm;
- segment length - 1000 mm;
- the inner diameter of the half-cylinders is 22-1220 mm.
Some industries produce products of other sizes. So, for example, there are pipe diameters of 57-1020 mm, and the thickness of the insulation ball can vary from 30 to 70 mm. These changes depend on the equipment used for the manufacture of PPU shells.
Advantages of this type of product
When comparing PPU shells with mineral wool of the same thickness, it turns out that polyurethane foam conducts 2.5 times less heat than its analogue.
This insulation can withstand operating temperatures up to 130 degrees Celsius, short-term - up to 150.This is evidenced by the absence of snow melting in winter under a heating main protected by a polyurethane foam interlayer.
With the correct installation of the PPU shell, reliable hydro- and vapor barrier of pipes without the formation of condensate is ensured, which prevents the appearance of corrosion and fungi.
The low hygroscopicity of the insulation when used on pipes with a negative temperature avoids the installation of a vapor barrier layer, and this, in turn, reduces the cost and time spent installing the PPU shell.
When accidents occur on network sections, the polyurethane foam product is easy to open, and then it can be used repeatedly. Moreover, the dismantling and installation of the PPU shell is allowed in any weather and regardless of the season.
Installation of polyurethane foam shell
Installation of the PPU shell is carried out using two methods: quick and standard. Quick installation involves fastening the insulation with special ties or wire.
In a standard installation, the pipe is first prepared, the old insulation is removed, the surface is degreased. To extend the operating time of networks, it is necessary to cover the pipe with paints and varnishes.
Further, from the inside, the insulation is impregnated with polyurethane foam glue. In order to achieve the best possible compound effect, the same surface is treated with water droplets of a fine dispersion. Then the insulation is put on the pipe and fits well with the help of clamps.
PPU shells are protected from ultraviolet radiation and mechanical damage by special mastics or enamels. Additionally, it is possible to install a casing made of galvanized steel or polyethylene with a seamless connection.
