[Industrial Cleaning]
Four Major Methods for Industrial Cleaning of Stainless Steel Plate Products
The commonly used industrial cleaning methods for stainless steel sheets mainly include four types: physical cleaning, electronic cleaning, electrostatic cleaning, and chemical cleaning.
Physical Cleaning Method
This method involves the use of manual tools and machinery to apply external force to various types of dirt for removal without changing the composition of the dirt. In other words, this is a method that does not alter the original chemical molecular composition of the dirt. The main types include mechanical cleaning, brush and scraper cleaning, tubing cleaning, and shot blasting cleaning.
Hydraulic Cleaning Method, low-pressure hydraulic cleaning (the pressure of low-pressure cleaning is 196-686 kPa, approximately 2-7 kgf/cm², equal to 0.2-0.7 MPa);
High-pressure water jet method, high-pressure hydraulic cleaning, the pressure of high-pressure cleaning is 4900 kPa, approximately 50 kgf/cm², equal to 5 MPa. This method is also called high-pressure water jet method or high-pressure cleaner.
Electronic Cleaning Method
The principle of descaling is to change the molecular structure of water using a high-frequency electric field to prevent and remove scale.
When water passes through a high-frequency electric field, its molecular physical structure changes. The original associated chain-like macromolecules break into individual water molecules. The positive and negative ions of salts in water are surrounded by individual water molecules, their movement slows down, the number of effective collisions decreases, electrostatic attraction drops, and they cannot form structure on the heated wall surface of pipes, thus achieving the purpose of scale prevention.
At the same time, because the water molecules’ dipole moment increases, their ability to attract the positive and negative ions of salts (scale molecules) improves, making the scale on the heated surface or pipe wall loosen and easily fall off, producing a descaling effect.
Electrostatic Scale Prevention Method
The electrostatic scale prevention method has the same principle as electronic descaling, which is to change the state of water molecules to prevent and remove scale. The difference is that this method uses the effect of an electrostatic field instead of an electronic effect. Specifically, the mechanism utilizes the polarity (also called dipole) of water molecules. When the water dipoles pass through an electrostatic field, each water dipole will align in an orderly positive and negative sequence.
If there are dissolved salts in the water, their positive and negative ions will be surrounded by the water dipoles and arranged in positive and negative order within the group of water dipoles. They cannot move freely and therefore cannot approach the walls of pipes or equipment to deposit and form scale. At the same time, the oxygen released in the water can form a very thin oxide layer on the pipe wall, which can prevent corrosion of the pipe (or equipment) walls.
Chemical Cleaning Method
Chemical agents can be used to react with surface contaminants or coating layers (such as scale) to remove them, such as acid or alkali cleaning of scale layers.
To prevent the substrate from being corroded or to control the corrosion rate within allowable limits during chemical cleaning, it is usually necessary to add an appropriate amount of corrosion inhibitor and additives that activate, penetrate, and wet the surface in the chemical cleaning solution.
