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One of the important things to pay close attention to is the quality of the filter plates, which are the heart of the filter press operation.
Not only is it necessary to select the plates according to the specific process, but it is also important to be sure of the quality of the material and workmanship.
The first thing, of course, is to opt for filter plates suited to the specific requirement, as plates
are clearly not all the same.
They change in size, volume, material, provision for other options (such as drying, etc.), resistant to high temperatures, with or without a membrane (which may itself be interchangeable or fixed), with or without seals to prevent dripping, with screwed or cast handles, with or without embossing, etc.
So, depending on the pH of the product, the temperature and the size of the chamber, we will have identified the type of plate we need.
Now at this point, it is highly recommended to choose high quality plates in terms of construction and materials, especially with regard to the type of polypropylene (for simplicity we will focus on this material which corresponds to 90% of cases) used (there are virgin polypropylene plates and regenerated polypropylene plates, for example) and with regard to machining.
In fact, filter plates are normally machined, precisely to guarantee one of the fundamental requirements: flatness.
Of the various quality requirements for filter plates, flatness is certainly one of the most important.
Flatness for a filter plate is a requirement of strategic importance, because when I go to form the plate pack, I must be sure that the flatness between the head and tail of the plates is respected.
If the plates are not flat, at the moment when the cylinder presses the plate pack against the fixed head, I can have even the straightest and most straight frame in the world that the machine bends or deforms dangerously or even irreversibly. This phenomenon is then clearly more pronounced the higher the number of plates.
It is therefore necessary to have top-quality filter plates, which, once installed, solve the problem and remain in life for many, many years.
Always ask for the certificate of origin and the batch number to trace the date of production, that way you will never have any surprises about the origin.
Be wary of anyone who offers you used plate packs without knowing their origin, or anyone who repairs plates or plasters them with fibreglass, as the ultimate aim is then to sell a plate pack again once its warranty has expired, and then you are in trouble.
fibreglass, as the ultimate aim is then to sell a plate pack again once the warranty has expired, and then you are in trouble.
Plies are part of consumables, whereas plates – if correctly sized and chosen – can last dozens of years.