Structure And Fitting Principles Of The Commonly Used D-Type High-Temperature-Resistant Silicone Semi-Circular Strip For Air Preheater Sealing

The air preheater is a critical component within boiler systems, responsible for recovering waste heat from flue gas to preheat combustion air. Since a minute gap exists between the rotor edges and the outer casing, sealing materials possessing excellent elasticity, high heat resistance, and strong shape-recovery capabilities are essential to prevent air leakage and enhance heat exchange efficiency. The "D-type" sealing strip-characterized by a cross-section featuring a semi-circular top and a flat, right-angled base-is designed to fit snugly against the metal casing's edges. Under compression, its hollow internal cavity compresses and rebounds, creating a dynamically adaptive seal; consequently, it is widely utilized for radial, axial, and circumferential sealing applications within air preheaters.

During a recent maintenance inspection of our facility's aging boiler room, we discovered severe air leakage through the seams of the air preheater; cold air was rushing in, resulting in a noticeable decline in thermal efficiency. We subsequently installed this transparent silicone D-type sealing strip. Installation was effortless: we simply peeled off the adhesive backing and pressed the strip firmly into place; the edges adhered perfectly without curling or lifting. In high-temperature zones-where we recorded continuous operating temperatures of 180°C-the material showed no signs of softening, deformation, or stickiness; it remained flexible and elastic to the touch. The strip's semi-circular profile creates a smooth, natural transition, offering superior water- and dust-blocking performance compared to rigid rubber strips; furthermore, it resists detachment caused by thermal expansion and contraction during equipment start-up and shut-down cycles. When applied to the joints of the air preheater's sector plates, the strip also improved noise reduction; the previously audible "buzzing" sound of air leakage has now become virtually inaudible. Finally, the transparent nature of the material ensures an unobstructed line of sight, allowing maintenance personnel to instantly assess the condition of the seal at a glance-providing both peace of mind and operational confidence.