Heat from the heating boiler reaches radiators piped through coolant circulation. If no heat insulation pipe is made, the loss of some portion of heat is inevitable, as the conduit in contact with the environment and gives the heat energy to it.
Factors causing heat loss
When placing the entire heating system in one room heat loss would be minimal - only through contact and conduit unit with bases, remaining heat from all elements of the system would be transmitted into the air housing. But in practice, there is always a number of factors that lead to loss of thermal energy:
- boiler and part of the pipeline are often located in areas, in which the heating is not necessary;
- the boiler is mounted in a separate structure and is connected to the heating outer pipe;
- private accommodation heating system draws coolant from the central highway, located at some distance from the house.
To improve the efficiency of the boiler, reducing the heat loss in all these cases, insulation and intended for heating tubes located outside the area in need of heating.
Developing are not only insulated heating pipes, for the following reasons also performed insulation of water pipes and sewage systems:
- hot water system heat insulation needs water to maintain its temperature during movement from the heat exchanger to the point of intake;
- regular water supply and sewerage in the winter without heat insulation equipment promorznut and will fail.
In addition to reducing heat loss and prevent freezing of pipes, heating pipes for insulation performs another function - protection against burns in direct contact with the human body. In order to successfully carry out its tasks insulating materials must have certain characteristics, originating from the requirements imposed on them.
Requirements for insulation materials
An ideal heat insulating layer should have a set of characteristics listed below:
- small heat conduction coefficient - the basic requirement of outgoing destinations material;
- thermal stability - a sufficient degree of stability to temperature while maintaining the basic characteristics;
- Low combustibility - grommet must not keep the fire and, moreover, be means for its propagation in the event of fire in a room;
- dielectric properties - upon failure of an electrical grounding device boiler heat insulating pipe shell should not become a conductor of electric current;
- acceptable share of - Thermal insulation shell should not create significant additional load on the pipe support;
- lack of hygroscopicity - the material must not absorb and accumulate a water from the environment;
- water resistance - an insulation coating has to protect the pipeline from corrosion;
- vapor permeability - under abnormal getting wet sealant should dry quickly and regain its insulating properties.
In practice, the materials with which satisfied insulation pipe heating outdoor and rooms, all of these requirements correspond to different degrees, so have both advantages and limitations.
Important! When choosing a heat insulator is necessary to consider the conditions of his upcoming operation to acquire the shell with the most popular properties.
Types of thermal insulation materials and their application
Insulating materials of mineral wool
Materials made of mineral wool for insulating pipelines used for a long time, their properties are well known, and the installation is not technically complicated.
For execution meant mineral materials are divided into the roll (all season), sheets (in the form of mats and molded (ready shell fixed geometry for pipes and couplings - tees, elbows and etc.).
Modern varieties of mineral wool insulation produced in the form of foil on one side of the layer insulator stitched over the entire area or mesh reinforced glass fiber (as an option - of thin steel wire).
species insulation of mineral wool made from the following materials:
- fiberglass;
- basalt wool;
- based on the slag.
Thermal insulation glass wool
Most long known material commonly used in industry and at home, which manufacture original raw material - mixture of quartz sand, glass breakage, soda ash, dolomite.
Advantages of glass:
- incombustibility - due to the primary source of manufacturing raw material (quartz sand), the maximum heating temperature - 450 °, after which the destruction begins.;
- low specific weight - does not create significant additional load on the support and spans the pipeline;
- low thermal conductivity - good reduces heat loss and protects it from direct contact with burns;
- water vapor transmission rate - in case of emergency getting wet dries quickly;
- durability - does not decompose under the influence of external factors;
- neutral towards contactee materials - do not react with the pipes and the protective sheaths, is not a catalyst for other processes;
- availability of all the value range.
Disadvantages:
- permeability - over device necessitates insulation shrouds of galvanized corrugated iron or plastic;
- hygroscopicity - absorbs and accumulates moisture from the environment;
- considerable shrinkage - accompanied by a deterioration in insulating properties;
- the need for the installation of individual protection means - releases into the air the smallest pulverized glass dangerous to humans when inhaled.
Scope - outer portions pipeline heating systems and water supplies, particularly in industry, where large areas of the insulated surfaces. lifetime stated by the manufacturer is 30 to 50 years, but there is no practical evidence of this.
Stone wool insulation
This material is made of natural stone (typically - basalt) with a small amount of limestone, which increases its plasticity and ukladistost.
Composition - rolls, sheets, mats.
Stone wool varies along the length of the fibers, which causes its vibration resistance - the shorter the fiber, the lower the resistance.
basalt heat insulation material by virtue of its composition and the particular structure has advantages over glass wool insulation:
- safety of the installation - no harmful fugitive dust;
- absolute incombustibility - application temperature to 600 deg .;
- hydrophobicity - lack of hygroscopicity and the presence of water repellency;
- higher thermal insulation properties (thermal conductivity 0,0077- 0,012) - due to the chaotic arrangement of the fibers in the insulation.
For rock wool the advantages listed above, you can add the rest of the virtues, which has glass wool insulation.
Among the shortcomings can be noted bulkiness shell is undesirable at the indoor unit heat insulation - aesthetic issue of such solutions is low.
When the apparatus thermal insulation and water heating systems mounted basalt wool layer also needs a protective sheath galvanized iron or a plastic material that protects against mechanical damage, dust, thermal conductivity improver filling voids.
Scope - insulation of piping and valves at the outer portions of industrial and domestic heating, water supply and sanitation, as well as the performance of thermal insulation of building structures and flues.
slag wool
The material for the production of slag wool are waste blast furnaces - slag, which is processed by additive bonding to the insulating material of the fibrous structure, the maximum temperature of use which is 250 deg.
The material of the three kinds of mineral wool Least preferred to use as a heat insulator due to the high degree of hygroscopicity, the driving perform leakproof protection sheath from contact with the environment.
In addition, the residual acidity present in the slag wool, when moisture on the sheath causes the formation of acid destructively operating on steel. Therefore, the use of steel slag wool on pipelines is limited due to additional cost associated with the neutralization of these factors.
The composition of the slag wool in small concentrations include phenol formaldehyde resins, which also complicates the process of working with the material need to perform protective measures.
Visual assessment of the technical characteristics of thermal insulation of mineral wool allows the reduction of the basic parameters of its three varieties of table:
Insulation of polyurethane foam (PUF)
Polyurethane - gas-filled plastic, polyurethane variety, up to 90% by volume of which consists of a hollow cell with gas (air). Initial raw material - polyurethane may also be different kinds of polyurethane foam causing texture: solid or resilient (foam). Flexible types of polyurethane foam for heat insulation device is not used, and hard widespread for both heating and domestic hot water, and sanitation.
For use as a heat-insulating polyurethane material tube comes in two forms:
- hard shell "shell" (whole or team);
- a liquid composition is sprayed onto the conduit and valving.
Solid form of insulation made of polyurethane foam
PUF-shell, normally foil outside, made by pouring into molds, designed for pipes, bends and tees certain diameter. The thickness of the shell is also different, depending on the operating conditions of the pipeline. Shell as a whole collar put on the pipe before installing it in place, prefabricated elements are mounted on already stretched conduit via locking profile cut edges or adhesive inner surface. Both methods of thermal insulation devices are economical because they do not need to perform time-consuming and costly for the shipping costs.
PUF-rigid shell have performance and aesthetic appearance are used in the production conditions, and in everyday life, but in order to protect from vandalism require additional installation of galvanized housings gland.
Liquid sprayed foam-formulations
A solution of polyurethane is applied to the pipe insulation and to the planned connecting members special atomizer, which is part of the set of equipment. As the curing envelope and the next layer is applied - so to achieve a heat-insulating shell design thickness. The method is very convenient because the heater penetrates into hard cavity and eliminates the laborious work to fit the solid elements in the areas of complex profile.
Application of insulation coating to produce special clothing using PPE. The efficiency of such insulation is very high, but the domestic heating pipe insulation by this method is not It made as it rascchitan on the large amount of work and, moreover, is accompanied by pollution surrounding areas.
Among the positive characteristics of PUR stands high degree of thermal insulation, almost zero shrinkage in service, good adhesion and waterproofing properties. But these virtues polyurethane foam and has serious drawbacks:
- according to GOST 30244 - it is silnogoryuchim pictures (Group T4);
- according to GOST 30402 - it relates to the flammable substance (B3 band);
- GOST 12.1.044 relates to polyurethane foam materials with a high degree of smoke generation (D3) and toxicity (T4) during combustion.
There is another way of using polyurethane foam for thermal insulation of heating systems and water - in the production of so-called pre-insulated pipes. Pre-insulated pipes are tubular material enclosed in the factory in a sheath of polyurethane or other insulation, coated in turn, solid protective layer of polymer or become. Open end sections are only 15-25 cm long pipe - for connection to the subsequent performance of thermal insulation only splice site.
The use of this variety of pipe material eliminates the need to perform thermal insulation of heating pipes in the street as a separate type of work and system provides maximum efficiency of heating, but the price of pre-insulated line is significantly higher than the total cost of the pipe and insulation, purchased separately.
Polyethylene foam (polyethylene foam, PES)
This heat insulating material is a porous insulation, produced on the basis of polyethylene. Product Form - rolls and sheets (including foil), tubular shell - liner.
Widely used for insulation of pipes for heating and water, especially suitable for use tubular form material - the sleeve, producing a length of 2 m and a wall thickness of 60, 90, 130 and 200 mm.
PPE-insulation has high performance achieved by combining the advantages of polyethylenes - flexible, fusible material but with properties after foaming substances acquire low thermal conductivity, and specific gravity.
The production technology is polyethylene extrusion - the raw material in contact with the catalyst is melted in a special hopper, whereupon the pressure in the container is increased, the material swells and during this phase undergoes testing them through an extruder to impart desired products therefrom geometry.
The structure of the foam - small closed-cell bubbles, separated by partitions made of polyethylene and causing high performance PPE materials.
PUF insulation is applied in the manufacture of pre-insulated pipes that reduce turnaround time. PPU shell they carried out a two-layer variable-profile - for fixing insulation on the ground.
Specifications:
- high frost - the ability to maintain elasticity and heat-insulating properties at temperatures down to -60 deg.
- Density - 30-32 kg / m3;
- low thermal conductivity - 0.038 factor;
- high sound insulating properties - water circulation in the pipes occurs totally silent;
- low water absorption - up to 2% of its weight per month even in direct contact with water;
- high resistance to oils and mineral oils;
- stability to biologically active environments - fungus, mold, decomposition;
- sufficient heat resistance - Operating temperature from -50 to +90 degrees, above 102 deg. - deformed;
- moderate combustibility - flash point 300 deg .;
- Safety - the absence of harmful emissions in the combustion process even (decomposed into water and carbon dioxide);
- long life - service life without losing the characteristics of more than 60 years.
Pipe insulation of foamed rubber
This insulating material also has a closed cellular structure and belongs to the group of foam elastomers. The substance safe for the organism, and the material has a high performance
Conventional release form for insulation devices - coils, sheets and hollow tubes with a certain wall thickness, calculated on pipe sizes.
Foamed rubber has a list of all the positive characteristics of the PPE-insulation, different only numerical values, however its application is also widespread in the industry, and in home.
Important! Additionally insulating properties, foamed rubber and possesses anticorrosive properties - the inner layer of adhesive prevents direct contact with moisture and condensation duct.
conclusion
Each of these thermal insulation materials, there are varieties that allow to choose insulated material that best meets the requirements of the specific operating conditions. In addition, there are other materials used as insulation pipes, both traditional and modern high-tech used in industries with high demands on the temperature regime coolant.
The market for insulation materials is wide enough, after analyzing the specific conditions, make the best choice of insulation.