Clarity diatomaceous earth pool filter model DE-24

Diatomaceous earth filter

Diatoms are single-celled algae found in both fresh and salt water that have the ability to retain dissolved silicon in water. After they die, their skeletons fossilise to form a white, light, highly porous rock called diatomite. From this rock, dried and crushed, the diatomite powder used in water filtration is obtained. Thanks to the high porosity and small size of diatomite, of the order of 0.036 mm, particles of up to 5 microns can be filtered.

Inside the filter there are 8 filter plates injected in plastic and covered with a thin polypropylene fabric, called "septum". After introducing the diatoms directly into the skimmer (diluted in water in the form of a paste), they enter the filter at the bottom and are distributed evenly over these plates, forming a thin film that will be responsible for retaining the dirt in the water.

The clean water is collected by a collector located at the top of the filter and sent to the pool. Although the initial pressure drop in these filters is very low, their high filtration capacity means that they get dirty very quickly, in continuous operation, in less than 24 hours it would be necessary to wash them. However, in this type of filter there is a phenomenon of "automatic regeneration" of the filtering layer which allows the filtration period to be considerably extended.

Clarity filter characteristics

• Pressure gauge.
• Air purge.
• 1 ½" side selector valve.
• The "Clarity" diatomaceous earth pool filter has a diameter of 600 mm.
• The selector valve is lateral.
• Filtration capacity of 11.000 l/h.
• Diatomaceous earth load not included.
• FILTRATION SPEED: 4,9 m3/h x m2.

Automatic regeneration.

The diatoms remain attached to the fabric thanks to the force of the water. For this reason, every time the filtration pump stops, they detach from the screen and fall to the bottom of the filter. Thanks to the special design of the plates, which shake the mesh when the pressure is released, the diatoms are released as much as possible. In this way we obtain a paste at the bottom of the filter formed by diatoms and retained dirt.

When the pump is switched on again, all this paste is mixed due to the turbulence of the water and rises towards the plates to form a new layer ready to resume filtration.

Although the principle of operation seems simple, there are three fundamental details to which special attention has been paid in order to achieve maximum system performance:

• Maximum detachment of the diatoms from the plates.

Thanks to the special shape of the plates (in the form of "ribs"), a large filtration surface, an even distribution of the diatoms over their entire surface and maximum release when the pump is stopped, are achieved.

• Total utilisation of the diatoms.

One of the main problems with these filters is that the diatomaceous earth gradually accumulates in areas that are difficult to access, reaching considerable thicknesses and gradually reducing the useful diatomaceous earth for filtering. Thanks to the special design of the lower grid, with its conical shape and reduced surface area, the accumulation and loss of diatoms is avoided as much as possible.

• Uniform regeneration.

The special design of the lower part of the grate causes a great turbulence in the lower part of the filter which facilitates the homogenisation of the slurry and a quick and uniform distribution over the whole surface of the plates. This results in a prolonged cycle time and improved filtration.