Boiler tube shields are mainly used on the windward side of the heating surface of the boiler, such as superheaters, reheaters, economizers, and water-cooled wall pipes.
Table of Contents
Main usage
The main role is to protect the heating surface of the boiler pipes, reduce pipeline wear, and increase the heating surface of the pipes.
Erosion shields are used to protect boiler tubing from the highly erosive effects of high temperatures and pressures thereby greatly extending tube life.
We offer shielding for tubing, covering straight, bent and finned sections, as well as the clips that hold these in place.
In the long term, these shields more than pay for themselves, preventing the costly replacement of tubing and avoiding the downtime that results from tube breakdown and leaks.
In general, most of them are called “wear-resistant tile” and “wear-resistant cover plate”. Erosion Shields are special boiler accessories.
Generally, most of them are used in power station boilers, small boilers are used less, and some coal chemical industries will also use them.
Tube shields production process
Why use wear resistant ceramic coatings？
Install
Install erosion shields with snap ring
The snap ring is a short section that is installed on the pipe in conjunction with the wear-resistant tile. Generally, it is welded to the wear-resistant tile by lap welding, that is, to cover the wear-resistant tile slightly, so it is larger than the wear-resistant tile. The opening arc is Around 190-200 degrees, the welding position needs to be set aside to facilitate welding and fixing. The width of the snap ring must not be less than 20mm.
The installation requirements of anti-friction tiles of different shapes are slightly different. Basically, each anti-friction tile is installed with not less than 2-4 snap rings. The snap ring and the anti-friction tile are welded together to prevent expansion due to heat. The tiles fall off, and the joints are required to be fully welded.
Type of snap ring
U-shaped snap ring
The inner diameter of the U-shaped snap ring is the outer diameter of the wear-resistant tile plus the thickness of the wear-resistant tile, and the length varies from 20mm to 70mm. It will be 5mm more in a semicircle. The extra part during installation will hold the wear-resistant tile and then spot welde. Compared with the butt-type semicircular snap ring, it is stronger after holding the wear-resistant tile and welding.
U-shaped snap ring
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Material
Different types of stainless steel are selected according to the specific conditions of different working conditions.
Common materials are: TP321 (Cr18Ni9Ti), TP309S (Cr23Ni13), 1Cr20Ni14Si2, TP310S (Cr25Ni20), 1Cr25Ni20Si2, and some low temperature areas (such as low temperature superheater, low temperature reheater) are made of 1Cr13, 1Cr6Si2Mo and other materials.
The boiler was originally designed to be accurate. Different materials have different temperature resistance and mechanical strength. 1Cr13, 1Cr6Si2Mo generally has a temperature resistance of 600 ℃ or less.
Service life
The service life of boiler tubes erosion shields is different in different types of boilers and different use parts.
The normal service life is a period of overhaul (3-5 years) for the boiler. Generally, some boilers will be replaced or retrofitted every time the boiler is overhauled. The main replacements are those of the Boiler Tubes Erosion Shields that are severely thinned and exceeded the standard; those that were not firmly detached during the boiler operation during the previous installation. According to the wear of the Boiler Tubes Erosion Shields during replacement, if the thickness is severely reduced, it needs to be replaced, the deformation is severe, and those that cannot protect the tube also need to be replaced. In addition, some boiler tubes are not equipped with Boiler Tubes Erosion Shields, but during the boiler inspection, it is found that the tubes have a tendency of wear and thinning. Generally, Boiler Tubes Erosion Shields are also installed to prevent further wear of the tubes and cause serious consequences such as boiler explosion.
On the heating surface of superheater and economizer tube bundle of the boiler, in order to prevent the pipe from being worn by high temperature flue gas washing, boiler tubes erosion shields are mostly arranged on the outer side of the pipe in the direction of flue gas flow. The elbow erosion shields solves the abrasion problems of water wall tubes, superheater tubes, economizer tubes and reheater tubes in the furnace, and provides guarantee for the long-term and reliable operation of CFB boiler. With the increase of CFB boiler products, the type and quantity of The elbow erosion shields will increase.
