Precon-W precoating powder
Precon-W precoating powder is a dry powder, it is chemically inert and has an average particle size of approx. 10 nm (1/100 µm).
Precon-W is used for the preconditioning of pleated filter elements (filter cartridges & filter panels) that come into contact with fine, smoky, sticky dust in difficult applications. This is mostly separated in the following applications.
- Welding fume extraction
- Plasma cutting
- Laser cutting
- Thermal spraying (Zinc spraying, aluminum flame spraying, plasma spraying)
The preconditioning acts as a separating layer between the filter medium and the dust cake and prevents the dust particles from penetrating the structure of the filter medium and settling there. It serves as a "lubricant" between the dust particles so that the dust layer does not become encrusted and can be easily cleaned off by the cleaning impulse.
Precon-W initially closes the open pores of the filter medium and prevents the passage of dust particles and thus shifts the filtration from the depths of the filter medium to the surface of the Precon-W layer.
First of all, the dust extraction system is put into operation without the application of dust (ideally air to cloth ratio < 60 m³/m² h). The nominal volume flow is set and the now prevailing differential pressure is determined (approx. 100 Pa). Now, with the cleaning system switched off, Precon-W is added to the raw gas flow in small quantities (approx. 5 -10 g / m² filter surface). The differential pressure is observed here and should increase by approx. 700 - 800 Pa at the nominal volume flow.
In filter systems with unfavorable and uneven raw gas flow, it is advisable to add a somewhat larger amount of Precon-W to ensure that the entire filter surface is covered. The actual dust application can now be started. The filter system should be operated without cleaning until a differential pressure of approx. 1600 Pa is reached.
When the cleaning is switched on, it must be ensured that it is operated as gently as possible, i.e., with a low cleaning pressure. The differential pressure must not drop below 1000 Pa during the cleaning process. In order to ensure this even with irregular dust loads, a differential pressure-controlled cleaning system must be provided in any case.
If all these points are met, it can be assumed that the preconditioning with Precon-W only has to be carried out once, namely during commissioning.
Unfavorable factors such as
- too high air to cloth ratio,
- poor raw gas flow,
- uneven cleaning,
can cause the differential pressure to rise higher than described. This can be compensated for by measures such as post-conditioning at certain intervals or by additional cleaning when the system is idle.