Re-coating of glass-lined reactors
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When inspecting a glass-lined reactor upon delivery, how is the quality of the enamel layer checked? If a problem is detected, how do I fix it? Is it a local repair, repolishing, or a complete re-glazing? In the case of repolishing, is it necessary to cut off the jacket? We order reaction vessels from large manufacturers – why can there still be problems with the enamel coating? Is there no factory inspection? Could it be that our workers accidentally damaged the enamel layer while installing the reactor, and are shifting the blame to the supplier?
It would be great if the poster could upload a photo; the approach to take depends on the extent and location of the damage to the porcelain layer – minor damage can be repaired locally. If the area is large, double enamel coating is the only option. For this, the jacket has to be removed, the existing enamel taken off, the surface ground again, sandblasted, then a primer applied and fired; after that, a topcoat is applied and fired as well. The topcoat needs to be applied several times during the firing process. The cost of re-glazing is also significant. Glass-lined equipment is inspected before leaving the factory; the ceramic layer undergoes high-voltage testing. If there are obvious problems with the ceramic surface as you mentioned, it is likely due to damage during transportation or installation. If the issues are things like pinholes or discoloration of the ceramic surface, then it is the responsibility of the manufacturer.
Quality inspection of glass-lined reactors 2 1. At a distance of 250 mm from the surface of the glass lining, use a 36V, 60W hand lamp to visually inspect the surface of the glass lining; it should be free from the following defects: (1) cracks, fish-scale-like defects, and local peeling; (2) dark bubbles and warts; (3) obvious scratches; (4) local deformations caused by the firing brackets that interfere with the operation of the equipment; (5) cracks that affect the proper functioning of the equipment. 3 2. There shall be no more than 3 foreign particles per square meter of the enamel layer, and the area of each particle shall be less than 4 mm. 4 3. Color variations are allowed on the surface of the glass-lined layer, but it must be ensured that the properties of those areas with color differences do not affect the normal operation of the equipment. 5 4. The thickness of the glass-lined layer is 0.8–2.0 mm; for glass-lined agitators, the thickness of the glass-lined layer in the mechanically sealed section can be as low as 0.6 mm. The thickness of the glass lining should be uniform, with smooth transitions between different thickness areas.
Why cut the jacket? I have time to wonder: on what equipment is the lining process carried out? Is the entire reaction vessel put into the lining furnace? What is the glazing temperature then? Will baking the already glazed ceramic surface at such a temperature have any effects?