Static electricity. ESD protection
The existence of a person in a specific environment is associated with exposure to him (and environmental conditions) of electromagnetic fields. What conclusion can be made in the case of fixed charges? So, we are talking about electrostatic fields.
In this case, the nervous system of people is under great strain. This is due to the fact that electric fields from an excessive amount of charges affect the body, clothing and objects. The cardiovascular system of the body also responds to these phenomena.
What is static electricity? It occurs when an imbalance of intramolecular or atomic equilibrium occurs. This is due to the loss or acquisition of an electron. Normally, an atom is characterized by an equilibrium state. This is due to the same number of negative and positive particles.We are talking about electrons and protons. The first move easily from one atom to another. When this occurs, the formation of negative and positive ions. Thus, static electricity occurs when a similar imbalance occurs.
The main causes of
Static electricity can occur under the influence of a number of factors, among which are the following:
- Guidance. We are talking about the emergence of the corresponding field, which is caused by the charge. Static electricity very often occurs in industries that are associated with the processing of sheet plastics and roll films. The most common reasons for this are the separation of materials and surface contact. Charge generation occurs during the process of winding / unwinding materials. It can also happen while moving the layers relative to each other. It is worth noting that this process is still not completely clear. However, the most truthful explanation does exist. In this case, it is advisable to conduct an analogy with a flat capacitor.In it, when the plates are separated, the mechanical energy is converted into electrical energy.
- Cutting operations. As an example, you can take cutting machines.
- Strong electric fields that are uncharacteristic for industrial production. X-rays, radiation (meaning high energy values) and ultraviolet light should also be included in this item.
- Separation of materials from each other or their contact. This also includes unwinding, winding, friction, and so on.
- Rapid temperature drop. For example, it occurs at the moment when the material is placed in the oven.
More about hazards
Electrification of various materials may pose a threat to humans. In this regard, the rules of protection against static electricity is required to know everyone. The main danger lies in the possibility of a spark discharge. This applies to both an isolated conductive object and an electrified surface.
The possibility of discharge
This occurs when the intensity of the corresponding field above the surface of the conductor or dielectric (due to the accumulation of charges on them) has reached a critical value. The latter is sometimes called punching.This value for air is approximately 30 kV / m.
Sparks can cause flammable mixtures to ignite. This will happen when the released energy will be greater than that which contributed to the beginning of the fire. There is also a general meaning. This energy must be higher than the minimum similar parameter of ignition of the combustible mixture.
Why do you need to know the basic rules of protection against static electricity? In some cases, undesirable nerves and pain may arise from its effects. Sometimes this leads to an involuntary sudden movement of a person. As a result, he may receive any mechanical injury. In this case, a person’s own static electricity plays a big role.
There is a corresponding GOST. Static electricity can really be extremely dangerous. To reduce the risks, the permissible levels of tension of the respective fields are established. All this should be tightly controlled in the workplace. It is also necessary to comply with sanitary and hygienic standards.These requirements apply to fields that arise due to the electrification of certain materials, as well as during the use of installations. In the latter case, high DC voltage is implied. Their observance is the main protection against static electricity. GOST determines permissible levels of tension in the workplace. Also there are spelled out the general requirements for protective equipment and control. As for the permissible levels of intensity of electric fields, they are set taking into account the time of stay of employees at workplaces.
Choosing the right tools
Protection against static electricity can be organized in various ways. First of all, you need to take into account the following:
- Features of technological processes.
- Indoor microclimate.
- Physico-chemical properties of the processed materials.
Thus, an approach to organizing security measures is being developed. Removal of static electricity can be implemented in several ways:
- Elimination of the resulting charges.
- Decrease their intensity.
Regarding the latter case, the answer to the question of how to remove static electricity is as follows: this is achieved by reducing the force and speed of friction, increasing the conductivity of materials and differences in their respective properties. The following are practical guidelines:
- Reduce friction by lubricating. A reduction in the contact area of the interacting surfaces and roughness is also required.
- Friction can be limited by reducing the transportation of materials and their processing.
The most effective methods
Charges may form during splashing, spraying and splashing of certain liquids. Ideally, when such phenomena are eliminated completely. If this is not possible, then you should at least limit them as much as possible. For example, when filling tanks with dielectric liquids it is impossible to use a free-falling jet. In this case, the drain hose is guided along the wall in order to avoid splashing. Ideal if it is possible to lower it under the liquid level. The lower the electrical conductivity of materials, the higher the intensity of charge formation. Thus, it is desirable to increase the previously specified parameter of the existing elements.This can be done through the introduction of antistatic suckers. Accordingly, special linoleum should be used for flooring. Conducting periodic antistatic treatment of carpets is very desirable. This also applies to synthetic fabrics. It is desirable that the contacting substances and objects were made of similar materials. In this case, contact electrification is also excluded. For example, polyethylene powder should be stored in barrels of similar materials. It is better to transport and transfer it only with use of the corresponding pipeline and a hose. In some cases, this is not possible. Then it is acceptable to use materials that are close in dielectric properties. So, it is possible to draw a small conclusion that for the protection against static electricity it is necessary to use weakly or non-electrifying materials. You should also strive to eliminate the following phenomena in the work with the dielectric fluids:
If there is no possibility of complete elimination, then you should at least limit them to the maximum.
Humid air has sufficient conductivity so that the resulting charges can flow through it. Thus, in the corresponding environment they practically do not arise. On the basis of this humidification of the air - the most common and easiest way to combat static electricity. There are also other security methods. It is about air ionization. It is also a common method of dealing with electrical charges. The fact is that ions contribute to their neutralization. They are produced by a special device. The household ionizer has a lot of advantages. First of all, it helps to improve the air-ion composition of the air environment of the room. This eliminates the electrical charges that occur on clothing, synthetic surfaces and carpets. As for production, they use the most powerful ionizers. There are various designs. However, electric ionizers are most common.