Insulation is a special coating that helps humanity protect cables, pipes, and much more from damage, without which it is simply impossible to imagine life with its comfort. Before getting into the house to everyone, water, heat or electricity travel a long distance, and communications are most often located underground, where, in addition to the weight located above, moisture has a negative effect. Therefore, insulation is primarily protection, and the durability of the entire structure depends on its strength.
Cable sheath and its types
The outer coating of any cable has several layers that can provide maximum protection. It can be a special fabric, PVC, rubber, metal and its alloys. The insulation of the cable through which the electrical signal is transmitted may contain a screen made of a metal mesh, foil, polymer film, the surface of which may be coated with a metal alloy. Widepolyvinyl chloride is used, which is used as soft insulation. It contains 50% plastic substances in its composition, due to which the ability of the material to burn is reduced. This material covers high voltage power cables, as well as armored ones. Paper insulator is used in the production of power cables and is made from unbleached cellulose sulfate. Polyethylene is also used as wire insulation, through which voltage with various indicators will be applied, up to five hundred kilovolts. The specially wrapped cable has excellent mechanical properties and current protection. The material is durable, reliable in operation, and surpasses all other insulators in terms of thermal stability.
Metals-insulators
Metal is considered the best option for creating tightness and resistance to moisture, lead and aluminum are considered to be the most flexible and heat-resistant, they are widely used as wire insulation. The thickness of the sheath depends on the diameter of the cable, as well as the conditions in which it will be used. In the manufacture of lead insulation, lead grade C-3 is used, where the 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 when a cable containing only this sheath is installed vertically. The chemical activity of the material is low, which is complemented by high resistance to corrosion. The material has little resistance to vibration, especially under conditions of rising temperatures. Antimony additives are added during manufacture to increase stability. Aluminum for the manufacture of the cable is used grade A-5, the purity of the alloy is 99.97%. The density of the metal is 2700 kilograms per cubic meter, and the tensile strength is 39.3–49.1 megapascals. Such a sheath is 2-2.5 times stronger and 4 times lighter than lead. It is vibration resistant and also has shielding properties. But it is unstable to electrochemical corrosion, and the cable production technology is more labor-intensive.
Not just a shell
In addition to the shell, insulation is also a pillow, armor and a protective cover that 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 pillow containing a winding of two plastic tapes, due to which additional protection against corrosion or stray current is provided. 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 - "V". If the cable does not have a cushion, it is marked "B". The thickness of the cushion is between 1.5 and 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 mm, but such armor is used in the manufacture of products that will notundergo stretching. If tension is present, then the cable is protected by galvanized steel flat or round wire. The coating thickness of a flat wire is from 1.5 to 1.7 millimeters, and a round one is from 4 to 6 millimeters. Outside, there may be a non-combustible compound, which is designated as “H”, the extruded polyethylene protective hose is marked “Shp”, and the PVC hose is called “Shv”, the minimum thickness starts from 1.9 to 3 millimeters.
Pipes
Equally important, along with the cable, is the insulation of pipes, which helps them perform their functions for a longer time. Thermal insulation is most often used, which is aimed at protecting against freezing or at greater heat preservation. Insulation is an opportunity not only to keep warm and prevent an accident in case 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 wool is a universal insulator that allows you to protect from the cold, retain heat, and also has soundproofing properties. The material does not burn, and bas alt is used for its manufacture. From above, cotton wool can be covered with foil or galvanized. Polyethylene or polyethylene foam is also used, it has the form of a tube or canvas. The material resists moisture well and retains heat, which has led to its wide popularity. The pipe has a technological cut and an exact diameter.
What else can be insulated?
Synthetic foam 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 is not terrible for him either. Thermal paint, which belongs to liquid insulation, is also used, only a small layer is enough. The operating temperature ranges from minus 60 to plus 200 degrees. A pipe coated with such 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 adhesives, staples, adhesive tapes and other materials. Before insulating the pipe, it is worth making a thorough measurement. Insulation, as you know, does not happen much, but a small amount of it can lead to rapid wear.
