In the text you provided, webs function as elements connected to the chain (I do not think there are belts anywhere), that is the scrapers themselves. The scraper is zgrzebło in Polish.
In one of my sources, the scaper is broken down into constituent parts in which the web is an element that connects all the other elements of the scraper.
Element 12:
https://patentimages.storage.googleapis.com/US8662287B2/US08... It does not look particularly like a web of any sort. In fact, it does the job of scraping.
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The scraper webs do the entraining, so they have to be the active elements of the conveyor.