Filtering: retention of solids

1. Hydrocyclone filter (sand separator): separates large parts.
2. Gravel and sand collecting tank (gravel filter, seawater filter): spindle, clay, rust, moss, weeds, dirt, leaf, seed, insect, etc.)
3. Sieve Filter  (filter straw) - filter: very small parts and insoluble parts of fertilizers are filtered

When selecting a filter;
Type of water source (underground /ground)
• Capacity of water supply, capacity of the pump (10 M3 / h -1000 M3 / h)
• Degree of pollution (different from old and new wells)
• Usage status (fixed - portable)
• Working condition (manual - automatic).

The operating principles of the hydrocyclone:
It is a tool that separates heavy particles (sand, sludge, etc.) which can be found in water by the effect of centrifugation.
• Water enters from the upper part of the hydrocentrons to the wall and descends downward along the wall.
The water then rises up from the middle and the sand particles remains at the base since they are heavy..
• Purified Water is given to the system via a hydrocyclone.
• At the top of the hydrocyclone exit, an air discharge device (suction cup) is installed to release the air.
The sand deposited at the base is cleaned by opening the drain valve in the reservoir during the irrigation period and opening the lid of the tank when it is not in use.

Gravel Filters

In the reservoir of the sand/stone gravel filter tank, there is also a return pipe which allows penetration of water from the bottom and exiting from the upper valve.

The valves on the inlet and outlet pipes are closed during washing. The drain valve on the upper part of the tank and the upper cover open if necessary.

Water is supplied to the system, the water is lifted from the bottom to the top along the sand gravel layer and discharge from the drain valve or from the top. In the meantime, sediment and swimming particules in the reservoir have been thrown out.

However, the flow of washing water should not be high. Otherwise, sandy gravel in the tank may face the problem of transport. The quantity of water supplied from the bottom of the tank is determined by adjusting the washing valve.

Cleaning of the Sand-Gravel Filters 

Sand/Gravel Filter
The sediment and swim particules that can be found in irrigation water are kept. 
• Dirt water enters the tank from the top, clean water passes through the bottom of the tank after passing through the layers of sand and gravel. 
• In the meantime, sediment and swimming particules are usually held in the upper part. 
The bottom of the tank has a perforated tube surrounded by a screen filter. The goal is to prevent sand from escaping from the water tank.
• The frequency of washing depends on the amount of sediment and swimmer in the water.
The washing process is carried out on the pressure gauges that are placed on the inlet and outlet pipes when the pressure difference is 0.3 - 0.5 bar or is determined by the experience.

Sieve Filters

Screen filter, filters the sediments and the fertilizer particules that could not be filtereb by sand and gravel filters.
• The screen filter is placed in the control unit after the fertilizer tank.
• The filter is generally cylindrical.
• Can be composed of two individual or nesting filters.It is recommended that the screen filters are between 80 and 200 meshes.
• The mesh is the number of holes in length of 1 inch.
• In the drip irrigation system, it is extremely useful to install a low-capacity screen filter at the start of each maneuvering pipeline, except for a screen filter that is installed in the control unit if the area that will be irrigated is large.
• In this case, the fertilizer tank should be located at the enterance of the manifold pipelines before the screen filter, rather then at the control unit. This ensures a more efficient fertilization.
The fittings used up to the screen filter are usually galvanized. However, after the screen filter, hard plastic fittings are used without risk of rusting.
Types of filters that used fin line with water resources
Filters used in underground water resources
Low level pollution                                   High level pollution
Hydrosyclon                                           Hydrosyclon Systems
Filters used in surface waters
Gravel  Filters
Disk Filtres
If water is dirty, automatic filters should be used