Insulation is a special coating that helps mankind to protect from damage cables, pipes, and much more, without which life with its comfort is simply impossible to imagine. Before you get to the house for everyone, water, heat or electricity overcomes a great distance, and communications are most often located underground, where, in addition to the weight placed on top, moisture exerts a negative influence. Therefore, insulation is primarily a protection, and its durability depends on the durability of the entire structure.
Cable sheath and its types
The outer covering of any cable has several layers that are capable of providing maximum protection. This can be a special fabric, PVC, rubber, metal and its alloys. The insulation of the cable through which the electrical signal is transmitted may comprise a screen of metal mesh, foil, polymer film, the surface of which can be covered with a metal alloy. Polyvinyl chloride is widely used, which is used as a soft insulation. It in its composition contains 50% of plastic substances, due to which the ability of the material to burn decreases. This material covers high-voltage power cables, as well as armored cables. The paper insulator is used in the production of power cables and is made of unbleached cellulose sulphate. Polyethylene is also used as insulation wire, which will supply voltage with various indicators, up to five hundred kilovolts. Specifically, the wound cable has excellent mechanical properties and protection from current. The material is durable, reliable in operation, and by thermal stability it surpasses all other insulators.
Insulating metals
The best option for creating tightness and resistance to moisture is metal, the most flexible and heat-resistant are usually lead and aluminum, they are widely used as insulation wire. The thickness of the shell depends on the diameter of the cable, as well as the conditions in which it will be used. When making lead insulation, lead grade C-3 is used, where pure metal is at least 95.95%. The melting point is 327.4 degrees Celsius, but along with all the advantages the mechanical strength of this material is low, and the fluidity is increased, and this is a serious drawback with vertical installation of a cable containing only this shell. The chemical activity of the material is low, which is supplemented by high resistance to corrosion. The material has a low resistance to vibration, especially in conditions of rising temperatures. To increase stability, an antimony additive is added during the manufacture. Aluminum for the cable is used A-5, the purity of the alloy is 99.97%. The density of the metal is 2700 kilograms per cubic meter, and the ultimate strength is 39.3-49.1 megapascals. This shell is 2-2.5 times stronger and 4 times lighter than lead. It is vibration resistant, and also has shielding properties. But to electrochemical corrosion it is unstable, and the technology of cable production is more labor-intensive.
Not just a shell
In addition to the shell, insulation is also a pillow, armor and protective cover, which protects against damage, if the product does not have it, then the marking contains the letter "G". The pillow is made of fibrous material and bitumen, it is located on the shell. There is also a reinforced version of the cushion, which contains a winding of two plastic belts, thereby providing additional protection against corrosion or a stray current. Such a cable contains the letter "L" in the marking, two layers of tapes are designated "2L". If polyethylene is used in the winding, the designation will contain "P", and if PVC - "B". If the cable does not have a cushion, it is marked "B". The thickness of the pillow is from 1.5 to 3.4 millimeters.
Armor will protect the cable from mechanical damage, it can be made of two steel tapes with a thickness of 0.3 to 0.8 millimeters, but such armor is used in the manufacture of products that will not be stretched. If the tension is present, the cable is protected by a galvanized steel flat or round wire. The thickness of the flat wire coating is from 1.5 to 1.7 millimeters, and round - from 4 to 6 millimeters. Outside, there may be a non-combustible compound, which is designated as "H", the extruded polyethylene protective hose has the marking "Шп", and the PVC hose is called "Шв", the minimum thickness starts from 1.9 to 3 millimeters.
Pipes
Equally important with the cable is the insulation of the pipes, which helps them to fulfill their functions for a longer time. The most commonly used thermal insulation, which is aimed at protection from freezing or greater safety of heat. Isolation is an opportunity not only to preserve heat and prevent an accident in the event of freezing, but also to save money. The choice of insulators is huge, as well as the materials from which they are made, it all depends on the purpose of the pipe.
Types of insulators
Mineral cotton wool is a universal insulator that protects against cold, keeps heat, and also has soundproofing properties. The material does not burn, but for its production basalt is used. On top of cotton wool can be covered with foil or galvanized. Also used polyethylene or foamed polyethylene, it has the form of a tube or cloth. The material well resists moisture and retains heat, this has caused its wide popularity. The pipe has a technological cut and an exact diameter.
What else can you insulate?
Synthetic foamed rubber is also used , which can be in the form of both tubes and plates. The material does not rot and does not burn, moisture to it too is not terrible. A thermal ink applied to liquid insulation is also used, only a small layer is sufficient. Operating temperature ranges from minus 60 to plus 200 degrees. A pipe covered with such a paint is not only protected, but also has an attractive appearance. In order to attach the material to the pipe, you will need accessories, which are represented by glues, staples, adhesive tapes and other materials. Before you insulate the pipe, it is worthwhile to make a careful measurement. Isolation, as is known, does not happen much, but its small number can lead to rapid wear.