FAQS - FREQUENT QUESTIONS

1. Why use filtration in agriculture?
2. Why is it useful to filter water used in irrigation?
3. Why is it useful to filtrate water used in industrial processes?
4. Which are the characteristics of the spin filters with filtering discs?
5. Which kind of treatment offer spin filters with filtering discs?
6. Up to which filtration rate can filtering discs reach?
7. But, hasn’t a filtering disc got a little filtration surface?
8. What are filtering discs made of ?
9. Which kind of liquids can be filtered?
10. Do all the filters by you manufactured carry filtering discs?
11. Which is the difference between steady and dynamic filtering systems?
12. How does sand filtration work? (or grit/quartzite filters)
13. How does membrane filtration work ?
14. Which filters are more suitable to agriculture?
15. Which filters are more suitable to industry??
16. Which filters are more suitable for filtration in civil field?
17. How do back-washing or self-cleaning work?
18. Where must a filtration system be installed?
19. Can one install on their own a filtration system?
20. How much space is needed to install a filtration system?
21. Do the filtration system need electricity to work?
22. For how long do filtering discs and systems last?

Go back to the index ^ Why use filtration in agriculture?

• Filters represent a low cost investment (they can filtrate in perfect way any kind of water taken from sinks, canal, lakes, ditches, waste paper and so on)
• Maintenance is nearly un-existing » (see filtering discs)
• They can be easily used without any particular skills
• They have no external moving elements
• They filtrate continuously, even during self-cleaning phases
• They can be used also in absence of electricity
• They do not have consumable material to be replaced
  
   

Go back to the index ^Why is it useful to filtrate water used in irrigation?

• Drop irrigation systems require water free of sand, organic or solid dross to avoid drip blockage.
• For a proper running and maintenance of your irrigation system
• Certain kinds of crops (products to consume raw) require waters with a certain treatment.
  
   

Go back to the index ^Why is it useful to filtrate water used in irrigation?

• To save costs by re-using the same water more often (saving energy expenses)
• To improve system performance
• To save drainage costs of wastewater
• Because not always pipe water can be used
• To help environment » (see re-usage of water”)
  
  

Go back to the index ^Which are the features of the filters with filtering discs?

• They are compact, strong and always working
• Frame of the filters in stainless steel (corrosion resistant on the long term)
• They can filtrate continuously and without maintenance (also for months) with proper performance of filtration/self-cleaning.
• No specific skills are required
• They work without peculiar invasive installation
• The hydraulic version also works without electric energy
• They represent on the whole, a vast filtering surface
• They offer very high filtered liquid flow rate litres/hours
  
   

Go back to the index ^Which kind of treatment offer spin filters with filtering discs?

• Mechanical type filtration
   

Go back to the index ^Up to which filtration rate can filtering discs reach?

They range from 75 to 500 microns (from 200 to 35 mesh) according to the model of the discs.
Some discs can go down to 5 microns
 

Go back to the index ^But, hasn’t a filtering disc got little filtration surface?

No, on the contrary. Owing to its constructive features, a filtering disc, mounted in series with others, represent a very big total surface. According to the filter model you may have from 13.000 to 32.500 cm² of filtering surface with very big filtered liquid flow rates.  
 

Go back to the index ^What are filtering discs made of ?

They are composed by a plastic core on which polyester tissue is welded. Impurities are kept but they do not get stuck on the filter itself. Even with high pressures the discs never stops filtering. » (“see filtering discs”).

Go back to the index ^Which kind of liquids can be filtered?

Many liquids used in industrial processes even though major usage is dedicated to water filtration both in agriculture (irrigation) and various industrial fields for the re-usage of washing processes » (see “filtration”).
 

Go back to the index ^Do all the filters by you manufactured carry filtering discs?

No. Officine Meccaniche Parenti srl manufacture include, in addition to the self-cleaning discs filters, more traditional filters such as Hydrocyclones or quartzite filters.  
 

Which is the difference between steady and dynamic filtering systems?        Go back to the index ^

The following filters can be considered steady filters:

• Hydrocyclones
• Sand filters (or quartzite filters)
• Junior filters with discs

They do not have any component in movement. It is the liquid to be filtered that goes through the system in tangential way, (Hydrocyclones and Junior filters), or by gravity (quartzite filters)
The following filters can be considered dynamic:
Professional Filters (our exclusive patented production). The discs rotate operated by an internal hydraulic motor or by an electrical motor, according to the model. The combination between the tangential flow of the liquid in filtration and the discs rotation determines perfect filtration and a very high water flow of the filtered liquid.
 

Go back to the index ^How does sand filtration work? (or grit/quartzite filters)?

This is a very well-known method used to remove solid particles suspended in water. The means of filtration is represented by a sand layer with various dimensions and specific weights. When water goes through the filter, the suspended solid particles are kept in the layers as residuals while water, filtered, goes out of the filter. When the filter is full of particles, or dirty, by outlet pressure difference the flow is inverted, so the sand is cleaned. In our Dual or Arena models (with double chamber) the cleaning cycle never stops filtration.  
 

How does membrane filtration work?                                                                     Go back to the index ^

It consists of a physical barrier (filtering discs) which separates the particles from the fluid (micro filtration)
Also screen filters can be considered part of this group, however they need a constant maintenance, on the contrary of discs which are self-cleaning.  
 

Go back to the index ^Which filters are more suitable to agriculture?

It depends on many factors. Filtration in agriculture is mostly carried out by the usage of waters which may come from bores, ditches, lakes, canals and so on. The water quality which is to be filtered, therefore, determinates the filter choice. However, also the water flow to be obtained represents a choice factor as well as the presence or absence of electric power close to the installation place or the inlet water pressure. Here are a few examples….

• Quartzite filters (or sand filters) models Dual or Arena: slimy waters and waters with organic residuals
• Hydrocyclone Filters: bore waters with great quantity of sand and solid residuals
• Professional or Junior Filters: canals, rivers, lakes shallow waters
• Professional filters with Hydraulic motors: canals, rivers, lakes shallow waters with plants far away from electric net but with inlet pressure superior to 2 bar.

Some installations require more filters connected one to the other. For instance, a Hydrocyclone Filter, typical sand remover, connected to the inlet of quartzite or spin filters in batteries, lead to the knocking down of about 80-90 % of sand reaching an even more optimal filtration. Basically it works as a pre-filter for the mail filter.
 

Which filters are more suitable to industry?                                                         Go back to the index ^

Professional Filters. High filtration rate, vast filtering surface, great flow rates of outlet filtered liquid, continuous filtration also during self-cleaning, maintenance nearly un-existent.  
 

Which filters are more suitable for filtration in civil field?                                 Go back to the index ^

Professional Filters with self-cleaning filtering discs for their flow rate and continuous filtration; for the same features above stated.
 

How do back-washing or self-cleaning work?                                                     Go back to the index ^

It is the system that assures the efficiency of each filter and is activated either by means of pressure difference (drop) of the filtrated outlet liquid, or by means of a pre-set electronic control box (self-cleaning cycles).
In case of sand filters backwashing is determined by the liquid flow inversion.
In the disc filters self-cleaning is activated by a control box which controls the opening of a valve and is carried out with the same liquid used for filtration.
If self-cleaning cycles are properly carried out the filters operation will be optimal and long lasting without major maintenance.
 

Where must a filtration system be installed?                                                           Go back to the index ^

It depends on the type of plant and on the filter used. Our filters are manufactured by quality material and have the main body in stainless steel thus resistant to corrosion and weathering.
They can be installed outdoors, even though it is preferable to protect them by a shelter, especially in case of great flow rates Filtration Towers » (see Filtration Towers).

Can one install on their own a filtration system?                                                    Go back to the index ^

Professional Tower plants should be installed by specialized technicians and should undergo periodic maintenance.
If used as single, filters such Junior, Professional, Dual, Arena can also be installed in the “do it yourself” way provided that hand book usage, maintenance and warranty instructions are followed.
 

How much space is needed to install a filtration system?                                  Go back to the index ^

It depends on the target usage, on the plant dimensions, on the liquid do be filtered inlet and on the outlet filtered liquid.
Some applications for agriculture, in presence of single filters, can be installed also beside tractors or on mobile trolleys.
Highly professional applications (Towers) with very high filtered liquid outlets need very high rooms and structured support groundwork.
Basically there are no rules because the evaluation of many factors is indispensable. Certainly there is a solution for any requirement because our models can satisfy any need and fit in any installation place both vertical and horizontal.
 

Do the filtration system need electricity to work?                                                Go back to the index ^

Most of our models can work only by means of inlet liquid pressure, provided it is of at least 2 bar. To automate the filter it is used an electronic control box self-fed by batteries (autonomous for at least one working season or about 3.000 pulses).
 

For how long do filtering discs and systems last?                                                Go back to the index ^

A filtering disc, if properly used, can last for very long (2-3 years) being it made by nylon and polyester. Anecdotes could be told about some of our customers who completely forgot about their plant or cases in which, batteries ran out and the filter self-cleaning was not carried out. In spite of that, filters kept filtering.