In our country a lot of regions with severe winters. The temperature at this time is lowered to a significant negative marks. If in such circumstances the pipe has insulation, then it is unlikely to have a chance to stay intact for further use. To properly served conduit, its surface must be coated with a layer of thermally insulating material. As modern insulation used polyethylene insulation.
The use of such material has advantages in mounting and cost. There are many other good things. This is what will be discussed in this review.
Where applicable insulation made of polyethylene foam?
Insulation for metal pipes made of polyethylene foam is mainly used for water and sewage systems, in underground laying method. It is not necessary that they should be laid out on the street. Significant for areas with inadequate heating or its complete absence. Warming ensures that these pipes will not freeze in winter. Utilities run pipes, the material which has high thermal conductivity. This applies to steel pipes, fiberglass and polymer communications. Therefore, such a pipe is certainly in need of insulation.
In the bitter cold liquid in the pipeline and the pipeline just freeze with the formation of traffic jams. Movement of water through the system is terminated. Moreover, ice may expand and break pipe. It simply will not sustain strong inside pressure. Among the causes of accidents on the main highways are major failure or lack of insulation. We conclude that the thermal insulator savings in this case is inappropriate. The accident at the water supply will cost more.
Typically, when the process line laid underground at a depth that is lower than the ground freezes. But the pipe hot water and heating must be insulated to help prevent heat loss. The water and heat will be supplied to the customer in accordance with predetermined parameters.
Moreover, one should not forget the protection from noise that is created by water moving through the pipe. If the air conditioning system is used, then it shall be pipe insulation. This will help avoid a situation where condensation excessively. It is formed due to the temperature drop inside the tube and outside air. Excessive condensation prematurely wears out the system and disables its nodes. It is easy to see that such a material has a fairly wide range of applications.
What is similar to a thermal insulator?
For whatever purposes not intended this insulator, it always has a manufacturing technology. It is produced of different density and thickness. If it is to produce pipes, the shape of a cylinder with a diameter from 57 to 1420 mm and a length of 12.4 m. These dimensions are governed by regulations GOST 9,602. Release in a form greatly facilitates the installation work.
Production technology involves foaming molten polyethylene by passing the hydrocarbons through it. At the output give a web having a bubble structure with good characteristics of elasticity. Thus there is a significant increase in material dimensions. This figure may reach 20 times. The web is fed to an extruder to give it the desired shape.
The insulator produced in the form:
- web which can be rolled into a roll;
- shell (cylinder);
- plaits.
Production is carried out in two ways, as a result of which the final product contains the crosslinked and non-crosslinked polyethylene.
In the first embodiment, is passed on special equipment through the molten polyethylene propane-butane mixture. Or thus use permitted for use freon. Inside the extruder the pressure is artificially increased, and decrease its output. As a result, the material acquires bubble structure. Inside the bubble is formed gas. The material then cools down and becomes solid, and the shape is retained.
This type has a lower density than in the case of crosslinked polyethylene. At external examination, he has a larger cell. If the material is compressed, there is a characteristic crack, but to its original form, it does not come back.
Crosslinked polyethylene can receive radiation and chemically. This name was given due to the formation of cross-links. Thermal insulation produced from uncrosslinked polyethylene foam method is characterized by the presence of only linear chains. Transverse connection and represent a kind of "crosslinking."
The chemical method involves the process in which high pressure is used. The process is very complicated. There is a "cross-linking" with the help of initiators, through which carried out the cross-linking. The process takes place with the presence of high temperature. Radicals are formed, which are taken up in polyethylene is hydrogen. It is replaced by carbon to form the spatial structure.
Pipe insulation drawn extruded polyethylene radiation method, involves the formation of macromolecules by the action of directed energy beams. Crosslinked polyethylene has a higher strength and elasticity. It is characterized by a high density. it is compressed under pressure, and when it ceases to act, quickly comes to its original state.
Shapes and sizes of pipes with insulation
The length of the cylinder of polyethylene foam is usually up to 2,000 mm. Inside diameter should match the outside diameter of the pipe, which is subject to warming. Sometimes, they are issued with the presence of the adhesive composition. In this case the pipe can be insulated without dismantling it. If the pipeline is exposed to ultraviolet rays, the tube used with special coated. This protects the insulator from the harmful effects of ultraviolet radiation.
There may be a cylinder with a foiled coating. On the outer surface of such a material has a foil. It protects the heater from overheating or overcooling. web materials are used for insulation of complex structures. This also applies to pipe with a larger diameter.
The sleeve may be used. they are particularly relevant for cable systems. Such a material has small cells and in addition acts as a waterproofing. In this case we can speak of the universality of the material.
Coatings of polyethylene
The structure of the coating belt reinforced type pipe insulation favorably from extruded polystyrene foam. The tape has a number of advantages:
- high levels of adhesion;
- resistance to mechanical impact;
- low hygroscopic performance.
Coating of adhesive tapes are applied at the factory, on the mechanized production lines.
Structure-based coating applied to a bituminous mastic outer insulation. Used rubber or bituminous primer, which is applied to the prepared surface of the pipe. Thereafter applied outer layer of expanded polyethylene. Such a structure can retain heat at temperatures below -20 degrees.
Positive and negative moments of polyethylene foam insulation
The material has certain advantages:
- It has a lower thermal conductivity than other types. With proper selection of the thickness of it will be reliable protection from frost pipe.
- The heat insulator is safe for humans and animals. He did not have a negative impact on the environment. It shall be used in hospitals, as well as those that target children and adolescents.
- The material is resistant to chemical attack. With regard to mortars it shows inertia. Laying the foundation or through laying into the ground is not an obstacle to its use.
- Insulation is resistant to moisture.
- The material exhibits good sound insulation properties. Water when moving in the pipes did not perceived by the human ear, in other words, flows completely silent.
Reliable protection from cold and noise - Insulation enough tolerates low temperatures. Even in the cold of 60 degrees it will not lose its elasticity.
- Availability price accounts for its widespread use. It would cost almost twice cheaper than other kind of insulation.
- Installation works of such material simple and usually do not cause any problems. There is no need to use any special tools.
Unfortunately, there are also disadvantages, though their positive aspects easily overlap:
- Such material has a high flammability. It can not be used in those areas, which are increased requirements of fire safety. Such material can not withstand long flame. He is well-extinguishing, and when melted, can itself cause a fire.
- The material is not resistant to the action of ultraviolet light spectrum. If they planned to insulate the pipe, located in the street, you should use the kind with a protective coating. Otherwise, under the action of ultraviolet radiation it will lose its properties.
- Foamed polyethylene is unstable to the action of a mechanical nature. It can be easily damaged.
However, the advantages of this material is much greater than the disadvantages.
Features of the application
When the pipe insulation surface should be cleaned of dirt, and if the metal pipe, and then by rust. Apply glue "QUICK-BOND", "NP-88", "2136 Neoprene" other. Applied to the surface, and then fixed to dry completely.
Glued joint must also lock the tape. It can be used for this purpose and construction staples.
Using poliestirol foam for insulation, you can avoid problems with freezing pipes and break even under severe frosts.
