Insulation is a special coating that helps humanity protect cable, pipes, and much more from damage, without which life with its comfort is simply impossible to imagine. Before getting to everyone’s house, water, heat or electricity travel a long distance, and communications are most often located underground, where, in addition to the weight located on top, 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 are able to 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 include a screen of metal mesh, foil, polymer film, the surface of which can be coated with a metal alloy. Polyvinyl chloride, which is used as a soft insulation, is widely used. It contains 50% plastic substances, due to which the ability of the material to burn is reduced. This material covers
high voltage power
cables, as well as armored. A paper insulator is used in the manufacture of power cables and is made from unbleached cellulose sulfate. Polyethylene is also used as insulation of the wire, through which voltage will be supplied with various indicators, up to five hundred kilovolts. In a certain way, a wound cable has excellent mechanical properties and current protection. The material is durable, reliable in operation, and surpasses all other insulators in thermal stability.
Metal Insulators
The best option for creating tightness and resistance to moisture is considered to be metal, lead and aluminum are considered 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, C-3 grade lead 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 fluidity is increased, and this is a serious drawback when installing a cable containing only this sheath 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 in conditions of increasing temperature. To increase stability, an antimony additive is added in the manufacture. Aluminum is used for the manufacture of cable grade A-5, the purity of the alloy is 99.97%. The metal density is 2700 kilograms per cubic meter, and the tensile strength is 39.3–49.1 megapascals. Such a shell is 2-2.5 times stronger and 4 times lighter than lead. It is resistant to vibration and also has shielding properties. But it is unstable to
electrochemical corrosion , and the cable production technology is more laborious.
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 - “B”. If the cable does not have a pad, it is marked “B”. The thickness of the pillow is from 1.5 to 3.4 millimeters.
The armor will protect the cable from mechanical damage, it can be made of two steel strips with a thickness of 0.3 to 0.8 millimeters, but such armor is used in the manufacture of products that will not be subjected to stretching. If tension is present, 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 round - from 4 to 6 millimeters. Outside there may be a non-combustible composition, which is designated as “H”, the pressed-out polyethylene protective hose is marked “”, and the PVC hose is called “”, the minimum thickness starts from 1.9 to 3 millimeters.
Pipes
Equally important along with the cable is the
pipe insulation, which helps them to perform their functions for a longer time. Most often, thermal insulation is used, which is aimed at protecting against freezing or at greater heat preservation. Insulation is an opportunity not only to keep heat 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, keep warm, and also has soundproofing properties. The material does not burn, and basalt is used for its manufacture. Cotton wool can be coated on top with foil or galvanized. Polyethylene or foamed polyethylene is also used, it has the form of a tube or web. The material is well resistant to moisture and retains heat, this led to its widespread popularity. The pipe has a technological section and an exact diameter.
What else can you insulate?
Synthetic
foam rubber is also used
, which can be in the form of either tubes or plates. The material does not rot and does not burn; moisture is not afraid of it either. Thermal paint related to liquid insulation is also used, only a small layer is enough. 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 that are represented by glues, 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.