When inspecting a screening process, the suggested improvements are always dependent on the customer specific processing conditions and exact application. There is no universal solution to solve all screening media related challenges. A good start is to look at pegging, blinding, and maintenance – three areas which greatly impact the screening process.
Pegging and blinding issues
Pegging occurs when rocks get trapped in the openings of the screen surface. It can vary from minor pegging to the most challenging situation in which the entire cloth is clogged with rocks. Pegging limits screening capacity, and it can be difficult to know exactly what the best solution for the problem is. Initially, you should look at the size of the apertures to investigate why pegging occurs in your production. In the case of smaller openings, factors such as screen settings and conditions, level of flexibility and cloth design should be taken into consideration. With larger openings, crossbeams, ledge angles and other mechanical parts are factors to consider to prevent pegging.
Blinding is another performance limiting factor that highly influences your screening process. Blinding is a buildup of fines and dirt materials that stick to the screen surface due to humidity. It gradually covers the openings, and it can eventually cover your entire screen area. The level of blinding depends on how sticky the material is. To reduce blinding, there are a few actions which can be undertaken:
1. Minimize the blank area on the screen
2. Reduce thickness of media - if possible
3. Try softer synthetic materials.
Maintenance and installation issues
Maintenance and simple measures are often overlooked as factors that affect the performance of the screening media. In some cases, it is not the screening media that is causing the problem, but is actually related to other underlying issues. There are three key areas that need to be considered:
1. tension level
2. feed chute distribution
3. condition of the screen cloth supporting profiles
Whether your issues come down to pegging, blinding or a service-related issue, the key is to take a step back and look for the root cause to the issue before deciding on a quick fix. Bringing in a screening expert can also help you choose a solution that works for your specific site or screening operation.
Take a deeper dive into pegging, blinding and screen maintenance by visiting our expert blog page: How to improve your screening process with media - Metso
For the European market, new Trellex GS screening media is now available in both rubber and polyurethane depending on the application.
Content published in association with Metso
