Principles Of Operation - Astralpool 11619 Manuel D'instructions

ENGLISH
This manual has been specially written to guide the installer of filter as well as any person responsible for
its maintenance. Following the recommendations hereby started, which are a result from a long work
experience about filtration systems at ASTRAL company, you will get the best quality and the highest
crystallinity of your pool water.
1. INTRODUCTION
Diatoms are unicellular algaes existing in both fresh and sea water, they are capable lf retaining the silica
dissolved into water. After they die, their skeletons fossilize becoming a white, light and porous rock
which is used to water filtration. Due to the D.E. porosity and tiny size, around 0.0036 mm, it is even
possible to filter particles down to microns.

2. PRINCIPLES OF OPERATION

At the inside of the filter there are 8 filtering grids injection molded of plastic and covered by a thin, flexible
woven polypropylene cloth, called "septum". After introducing the D.E. directly into the skimmer (dissolved
into water), they enter the filter from the bottom and gradually distribute all over the grids making up a thin
layer called "filter cake" where dirt from water will be retained, (See Fig. 1).
Clean water is taken up by a top mounted grid manifold, then water returns to pool. Even though the initial
head loss on these filters is very low, their great power of filtration make them dirty very easily, when
operating continuously, it is necessary to backwash it in less than 24 hours.
Nevertheless, in this kind of filters a regeneration process occurs that lengthens the time between filter
cleaning.
2.1 The automatic regeneration
The D.E. keep attached to the septum due to the water pressure. That is the reason why, any time the
filtration pump is turned off, they are released from the septum and fall down to the bottom of the filter. It
is due to the special design of the grids, which shake off the septum when the pressure stops, that the
highest D.E. detachment is achieved. That is hoe we get, at the bottom of the filter, a paste formed by
diatomaceous earth and retained dirt.
When starting the pump, the whole pasta is mixed due in the water turbulence, then it goes up to the
grids and makes up a new filter cake which will ready to restart filtration (See Fig. 2).
Although the principles of operation seem to be simple, there are three fundamental details to which
ASTRAL has paid special attention in order to achieve the highest efficiency from this system:
• Highest D.E. detachment from grids
Thanks to the special grid shape (curved vertical grids) you achieve as follows: a large filtration area, a
D.E. uniform distribution all over their area and highest D.E. detachment when turning the pump off (See
Fig. 2).
• D.E. Total profit
One of the main problems from using these filters is that the D.E. paste is little by little accumulated in
difficult accessible areas and the number of useful filtering D.E. detachment when turning the pump off
(See Fig. 3).
• Uniform regeneration
The special design of the support grid's bottom causes a great turbulence at the lower area in the filter
that makes the paste easy to homogenize as well as it causes a quick and uniform distribution all over the
grids area. From all that, a longer cycle an better filtration are achieved (See Fig. 4).