Re-enamelling
The Reglassing is the re-application of an enamel coating (from Technisches e ) to an existing enamelled procedural apparatus (for example, stirred tank ) or one of its components and components (e.g., stirrer ).
When re-enamelling, an existing, usually worn or damaged layer of enamel is first completely removed with the help of sandblasting . Then damaged areas in the steel structure of the apparatus are repaired. If the pressure-bearing parts to be re-enamelled are to be re-enamelled, a pressure test is now carried out in the presence of a “ notified body ” in accordance with the Pressure Equipment Directive .
The apparatus or component is then subjected to a heat treatment at approx. 900 ° C in order to remove impurities on and under the surface to be enamelled later and to relieve the steel from stress. After another sandblasting and a dye penetrant test of the surface to be enamelled, the apparatus or component is enamelled again.
In many cases, re-enamelling also involves the revision and repair or replacement of other components of the apparatus, such as the drive or the mechanical seal . In addition, as part of a retrofit , the device can also be adapted or optimized to the operator's changed requirements. In many cases, the customer chooses more modern emails or improved stirring technology , which make the operation of the re-enamelled apparatus more economical.
After re-enamelling and reworking of the other equipment components, the operator has a virtually new equipment available, which can usually be used without restrictions compared to the original equipment. In addition, apparatuses are often equipped with new technologies in the context of re-enamelling, which increase the performance or the availability of the enamelled apparatus.
In order to improve the energy efficiency of glass-lined reactors, for example, it makes sense to equip the jacket nozzles with flow nozzles.
Depending on the state of the steel structure of the enamelled apparatus, several re-enamels are possible. The re-enamelling limit is reached, for example, when
- the cost of repairing damage to the steel structure of the apparatus would be uneconomically high
- the material properties have changed in an inadmissible manner as a result of a large number of firing cycles
- the wall thickness of the pressure vessel has largely fallen below the lower permissible limit
- the deformations and distortions caused by the burning of the components become impermissibly large
Implementation of the re-enamelling
In principle, it is possible to re-enamel apparatus and components from all manufacturers of enamelled apparatus at each of the manufacturers. In addition to the components to be re-enamelled, the re-enamelling company must also be provided with the pressure equipment documentation ( boiler log ) for the apparatus. In many cases it is particularly useful to have the re-enamelling carried out by a company which, among other things, has specialized in the corresponding process steps and has the corresponding expertise.
It is generally irrelevant from which manufacturer the apparatus to be re-enamelled comes.