3 things to know about industrial filters

How is an industrial filter maintained? How to understand when to do it? What are the technical aspects to know?

3 things to know about industrial filters

How is an industrial filter maintained? How to understand when to do it? What are the technical aspects to know?

What would happen to the dust filters at the top of a cement factory chimney if the nozzles in the fume cooling system were clogged? In a process plant a plugged nozzle can cause all types of issues, from troublesome maintenance problems to severe breakdowns.

Protecting a spraying system with an appropriately sized industrial filter is an important standard to safeguard safety.

PNR Italia has a wide range of in-line filter systems. From the smallest industrial filters up to large ones designed and built according to the specific customer’s needs and in the most suitable materials..


Basic information

The industrial filters

Some premises on industrial filters clarify the type of filters we produce and the type of liquid to filter.

Filtration refers to non-viscous liquids and therefore, in almost all cases, dirty water with contaminants of various origins;

When we talk about contaminants, we refer to solid or semi-solid pollutants, however never to fluids to be separated from the primary fluid;

In general, the filtration we are talking about serves to protect the nozzles -which are placed downstream of the filters and for which solid residues can cause obstruction.

What are the things to know about industrial filters? How and when do you do maintenance? What are the technical characteristics to take into account to choose the right filter?

1 | When to do maintenance on a filter

In most filters, the filtration takes place from the inside out of the filter element. Therefore, the contaminant is deposited on the inner wall of the filter element by clogging it and reducing the flow of the filtered fluid resulting in a pressure drop.

Therefore, if a drop in the filter outlet fluid pressure is detected, it is likely that filter maintenance will be required

1 | How to do maintenance on a filter


They are the simplest type of filters and require the manual intervention of an operator to replace the filter basket;


In these filters, the filter cartridge’s cleaning activity is entrusted to scrapers (blades or brushes) fixed to a shaft rotated by a gearmotor, activated by a differential manometer that reads the pressure difference between the fluid in and out of the filter itself.

A valve at the bottom of the filter body automatically opens during cleaning operations, allowing the material that clogs the cartridge to flow. The flow of the liquid is not interrupted but, during cleaning, is significantly reduced;


In this type of filter, the cartridges is washed by taking advantage of a part of the flow of clear liquid coming out of the filter. The liquid is forced to flow in the opposite direction, washing the cartridges.

In this way, the element concerned is cleaned up and the pressure difference returns to average values. Even in this solution, there is a loss of fluid during the cleaning cycle and, therefore, a drop in flow rate.

3 | What are the technical features to take into account when choosing an industrial filter

The elements that characterize a filter are numerous, but those fundamental for a first sizing of the equipment are:

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