FR2640614A1 - Device for the treatment of liquids such as water, especially in swimming pools, by long-duration ionisation - Google Patents

Abstract

The device is intended for the continuous treatment of a liquid such as water with a view to its purification by in-situ emission of metal ions from electrodes immersed in a stream of this liquid and raised to different electrical potentials, and it is characterised in that it comprises at least one ionisation cell for at least three electrodes 250-251-252.

Description

DEVICE FOR TREATING LIQUIDS
SUCH AS WATER, ESPECIALLY POOLS,
BY LONG-TERM IONIZATION
The present invention relates to an electrophysical treatment of liquids by in situ emission of metal ions, generally copper and silver, particularly well suited to the water of public or private swimming pools, but this treatment is also applicable to milk with a view to its conservation and its consumption, for water intended for human or animal consumption, for raising aquatic animals, for obtaining fertilizers, etc. However, to illustrate the invention, we will only retain here the only example of swimming pools.

 When creating a swimming pool, the determining elements are essentially immediate economic and aesthetic location, dimensions, choice of materials, colors, equipment, landscaped environment etc.

 It only takes a few days to realize that the main concern is monitoring and maintaining the quality of the water because it is constantly threatened: appearance of algae, troubles, unpleasant odors, without even mentioning the risks more serious due to bacteriological impurity.

 An open-air swimming pool has its water deeply affected by changes in season, temperature variations, rain, thunderstorms, a wind charged with dust and, which is less immediately noticeable, by the quality of the water. food which sometimes comes from far enough and which we do not always realize that it has physico-chemical & hanging characteristics due to various conditions: the natural river in which it is pumped at a variable level and drains with it more or, less acidic or basic products, a thunderstorm rain which occurred several hours or several days before changed its state and these are only a few of the most frequent examples. water quality is very difficult to achieve in practice because the users of swimming pools are always very demanding and want to have constantly water not only sterile on the biological level but also pure, crist alline, soft, tasteless and odorless. Even in the event of prolonged absence, the user intends to have flawless water.

 The incoming water (feed water) is first filtered but the filters, generally sand filters, can only stop large impurities: particles of at least ten microns while viruses and bacteria measure at most three microns and often less than one micron. Since they pass through the filters, they must be killed in order to sterilize the water before it is introduced into the pool.

 For this, we have known for a long time to use chemicals such as chlorine or bromine that we introduce into the water upstream of the swimming pool and, except for prolonged absence of the owner or maintenance personnel, it is theoretically possible to pay constant attention to the incoming water, analyze it and measure the parameters at all times to correct the chemical contributions accordingly by selecting various products and metering each one carefully.

 In reality, this constant monitoring is impossible to seriously consider and the minimum of monitoring, analysis and measurement is already considered tedious and painful.

 But, above all, the use of chemicals is less and less accepted, for the treatment of swimming pool water in particular, because it is felt as unnatural and, depending on the real or imaginary sensitivity of the users, it can be limit to inconvenience: bad taste, unpleasant odor, or cause more serious reactions: irritation of the skin, mucous membranes, eyes, allergies, deterioration of the hair, stomach upset, vomiting, etc.

 In addition, the use of chemicals supposes the regular addition of more or less large doses but which, in any case, cause inevitable non-negligible expenses.

It is estimated that in ten years maintenance costs equivalent to half the construction price. A small swimming pool 10 meters long and 5 meters wide requires maintenance in France which costs annually
- 2,500 F If the water is treated with chlorine,
- 3.940 F if the water is treated with a hexamé polymer
thylene biguanide,
- 4,000 F if the water is treated with bromine.

 In view of these drawbacks, it has already been thought of using other methods than the addition of chemicals.

 This is how an electrophysical process has been used for a few years by which metal ions, generally copper and silver, are dispersed in water. This process is the practical implementation of a phenomenon highlighted at the end of the 19th century, according to which minute quantities of metals have powerful effects on bacteria, algae and fungi. They are said to be "oligodynamic" (from "oligo", small and "dynamos", force).

 The electrophysical process consists in immersing two metal electrodes in water and bringing them to different electrical potentials in order to cause, by microscopic tearing, the emission of ions of the same metal as that of the electrode from which it originates.

 It is not necessary to describe here the physiological mechanisms involved because they are well known per se. It should only be remembered that the metal ions copper (Cu) and silver (Ag) cause the annihilation of bacteria, algae and fungi quickly and effectively when a certain concentration is reached and that one evaluates at approximately 0.2 to 1 PPM (part per million) for copper and 10 PPB (part per billion) for silver.

 Concretely, the water circuit of a basin such as a swimming pool is essentially a closed circuit with total or partial recycling of the extracted water. The supply of pure water comprises a complex inlet which will be described below, a movement pump, a filter and at least one inlet opening into the basin, generally below its surface but which can also be produced by falling , especially in the form of a waterfall for example. The arrival is called "complex" because it has at least three separate conduits: a conduit coming from a drain located at the bottom of the basin, a conduit coming from at least one drain (generally called "skimmer") located at the edge of the basin, in the manner of an overflow and a conduit coming from an external source.

 The electrophysical process is applied downstream of the pump and upstream of the filter to cause the flocculation of suspended matter, the invention of flocs by the filter and the destruction of microorganisms that create algae and mosses. On a conduit which connects these two organs, an ionization vessel is inserted in which are the electrodes which are "licked" by the moving water, which is charged with metal ions released under the effect of direct electric current low voltage leads to the electrodes by insulated wires connecting said electrodes to a power supply located in a housing.

Installations of this type that currently exist are not entirely satisfactory for the following reasons
As the water carries away the metal ions torn from the electrodes, they wear out and must be replaced regularly. However, this wear has the consequence of correspondingly increasing the distance between them. This results in a regular increase, of an exponential nature, in the electrical resistance considered between the electrodes. In addition, even if care is taken to regularly reverse the polarity of the electrodes, scaling and fouling effects occur which disturb the normal and regular functioning of the system. Monitoring the condition of the electrodes is therefore a subjection that imposes itself on the user and that he feels as all the more painful as access to the electrodes is more difficult: visual access for their verification and physical access for replacement or for cleaning the ionization vessel.

 At the same time, the phenomena mentioned above (rain, temperature variations, thunderstorms, etc.) intervene in a completely random fashion, which have a direct influence on the electrical resistivity of water.

 The conjunction of these two factors is currently the cause of large, absolutely uncontrollable variations in the concentration of metal ions in water.

 The release of anarchic ions destabilizes the desired concentration (0.5 PPM for all two metals) and can lead to significant inconvenience: blackish spots on the walls of the basin when there is excess copper, lack of security, pathological risk when there is a lack of ions.

 The present invention overcomes all the above drawbacks by allowing the system to adapt to all the changes occurring in the conditions of employment and by providing the user with very great physical and moral comfort: surveillance reduced to the ex- safety, operational safety, ease of maintenance, elimination of all chemicals, exceptional water quality constantly ensured, optimum conditions maintained even in the event of prolonged absence, etc.

 To this end, the subject of the invention is a device for permanent treatment of a liquid such as water with a view to its purification by in situ emission of metal ions from electrodes immersed in a current of this liquid. and brought to different electrical potentials, characterized in that it comprises at least one ionization vessel for at least three electrodes.

According to other characteristics of this device it includes at least one ionization vessel for an odd number
electrodes; the electrodes are arranged in a single line; the electrodes are arranged at the vertices of a virtual polygon; the electrodes are staggered along at least two lines
parallel; ~ The electrodes are arranged in a virtual parallelogram.

 The invention will be better understood from the detailed description below made with reference to the accompanying drawing. Of course, the description and the drawing are given only by way of an indicative and nonlimiting example.

Figure 1 is a diagram illustrating the phenomenon of ionisa
tion of a liquid from two usual electrodes, according to
the state of the art.

Figure 2 is a diagram illustrating the emission of ions with
two usual electrodes, according to the state of the art.

Figure 3 is a diagram illustrating the emission of ions with
four usual electrodes, according to the state of the art.

Figures 4 to 9 are diagrams illustrating the emission
of ions with electrodes arranged in accordance with the invention, according to
several variants.

 Traditionally, the electrodes used for the ionization of liquids are cylindrical and placed in lines.

 However, careful observation of the ion emission phenomenon has led the inventor to surprising observations, making it possible to achieve significant improvements.

Referring to Figures 1 and 2, we see two electrodes
classics A and B copper-silver immersed in water. The h electrode
is positive, it is an anode. The electrode B is negative, it is a
cathode. After reverse polarity (e.g. all seven
minutes), electrode A will be a negative cathode and electrode B
will be a positive anode. The explanations below are of course
valid mutatis mutandis for reverse polarity.

Positive anode A emits C ions by pulling out due to
electric field created by the passage of current in the conduc medium
separating the electrodes. These ions do not go directly
towards negative cathode B because the phenomenon is quite complex and we have
shown schematically in Figure 5 the combinations that occur, combi
We have already mentioned above.

Although the cathode is not completely "inactive", we
can admit, for the demonstration, that the diagram of figure 2 is
close to reality.

We have shown by arrows the emission of C ions and well
that the emission is not strictly limited to the half-perimeter of
anode A, it is understood that two electrodes can only create a single electric field generating a certain emission from the anode and no emission from the cathode. By convention, it is assumed here that a system with two electrodes has an "extraction efficiency" of 0.5 ions.

When a higher ion emission is required, that is to say when an installation has to be made for a large volume basin, four electrodes with alternating polarity (and of course periodically reversed) are used. , as shown in Figure 3. According to the convention set out above, such a system has an efficiency of 1.5, three times greater than that of a two-electrode system. Indeed, the anode E emits over its entire surface, on the one hand towards the cathode D and on the other hand towards the cathode
F while the anode G emits towards the cathode F.

 It is thus possible to produce systems with four, six, eight, ten electrodes, etc.

We can thus draw up the table below
Number Efficiency
tearing electrodes
2 0.5
4 1.5
6 2.5
8 3.5
10 4.5
12 5.5
14 6.5
etc. etc.

 It is immediately noted that the differential efficiency decreases and that it is maximum between the two and four electrode systems (300 X).

However, with regard to swimming pools, 35 X of them have a volume of 5 to 70 m3 for which a system with two electrodes is required; 50 X have a volume of 70 to 100 m3 for which a system with four electrodes is required. In other words, 85 X of the swimming pools must be equipped with a system with either two or four electrodes,
The sudden jump in efficiency means that many pools are "under ionized" and others are "over ionized".

 Example: to ionize a 40 to 70 m3 swimming pool with two electrodes, it takes more than two weeks and sometimes a month by adopting a permanent ionization day and night in order to obtain a concentration of 0.5 PPM of copper for water. normally conductive. During such a long period, it is essential to compensate for the insufficient protection by the use of chemicals (mainly chlorine). With so-called "soft" water, that is to say with a medium concentration of mineral salts (often calcium carbonate), it takes more than a month to hardly obtain 0.3 PPM of copper ions. With very soft water, that is to say with a low concentration (less than 0.6 grams per liter) of mineral salts, it is practically impossible to obtain a discernible concentration.

 Another example with a 70 to 90 m3 swimming pool requiring four electrodes: in one or two days, depending on the minerality of the water, the copper concentration reaches 0.8, even 1 or 1.5 PPM instead of 0.5 . It takes two weeks to lower this concentration, which means that the installation has to be stopped, an incomprehensible and worrying situation for a user of average attention who is limited to each restart (each spring for example).

 We have just shown that the current knowledge of a person skilled in the art does not allow him to obtain a suitable adequacy of an ionization system and of a swimming pool for the whole range of capacities commonly encountered.

 In accordance with the invention, a system with three electrodes is used, grouped either as indicated in FIG. 8, or as indicated in FIG. 9.

 In FIG. 4, the three electrodes 250, 251 and 252 are respectively a cathode (-), an anode (+) and another cathode (-).

Thus, the anode 251 emits both to the cathode 250 and to the cathode 252, an efficiency of 1 according to the above convention.

 It is the same with the case of FIG. 5 but it has been observed, without being able to fully explain it, that the arrangement of FIG. 5, according to which the electrodes are placed at the vertices of a virtual equilateral triangle, provides particularly regular ionization and is a preferred solution.

 After inversion of the polarities, there will be an anode 250, a cathode 251 and another anode 252 which will again provide an efficiency of 1 since the two "half" anodes will emit together towards the single cathode.

 We then continued the studies of systems with an odd number of electrodes to realize that their performance is much better than that of systems with an even number of electrodes.

 In FIG. 6, for example, we see a system with five electrodes in lines 253, 254, 255, 256 and 257. It is understood that the two anodes 254 and 256 emit towards the cathodes 253, 255 and 257, that is to say an efficiency of 2 which will remain after reverse polarity since there will be an anode 255 with efficiency 1 and "half" anodes 253 and 257 which together give an efficiency of 1, ie 2 in total.

 The five electrodes 253 to 257 have been grouped according to a trapezoid, that is to say at the five vertices of two triangles having a common vertex, virtual triangles and indicated in phantom in FIG. 7.

 The result is less good than with the alignment in Figure 6 because if we establish their polarity as shown in this figure, we have two cathodes 253 and 255 and three anodes 254, 256 and 258 and we see that the we have two neighboring anodes: 254 and 258. We rebalance the system by adding a sixth electrode 259 with negative cathode polarity to finally lead to an arrangement of six electrodes (even number) in two rows and staggered, the 'assembly having in plan the shape of a parallelogram.

 It can be seen that with the polarity indicated, the anode 254 emits towards three cathodes 253, 259 and 255 and the anodes 255 and 258 respectively towards cathodes 253-255 and 255-259. Reverse polarity retains exactly the same ion-stripping efficiency.

By grouping the electrodes in an odd number instead of grouping them in an even number as is the case until today, we obtain a much better distribution of efficiency since their differential values are more regular
Number Efficiency
tearing electrodes
3 1
5 2
7 3
9 4
11 5
13 6
etc. etc.

 If we compare the provisions of Figures 6 and 7 on the one hand and the efficiency tables with electrodes in even and odd numbers, we see that, finally, the invention has two essential embodiments: or the number of electrodes is odd and it is preferable to place them in line, except in the exceptional case where the number of electrodes is three, in which case we prefer the triangle arrangement of Figure 5; or else it is desired to place the electrodes otherwise than in a line and, for example, on at least two lines, in a circle, in a polygon, etc. in which case it is better to adopt an even number of electrodes.

 This appears clearly in FIG. 8 which represents the case where four electrodes (even number) 260, 261, 262 and 263 are placed at the four corners of a virtual square.

 The arrows show that the two anodes 261 and 262 emit towards the two cathodes 260 and 263 thus giving the system an efficiency of 2 while the conventional online arrangement (see table of even numbers) gives an efficiency of 1.5 for four electrodes .

 In FIG. 9, a system with six electrodes (even number) has been shown 270, 271, 272, 273, 274 and 275 are placed in two lines but not in staggered rows, unlike the case of FIG. 11.

Experience shows that this arrangement has a slightly lower efficiency than that of the same system with staggered electrodes, probably due to the fact that the electric field is more dispersed with the arrangement of Figure 9.

 Systems with an odd number of electrodes give a much more flexible solution to the problem of adapting an installation according to the invention to basins of different capacities.

For small volumes (less than 70 m3) their efficiency is perfect, ionization is reached quickly, even in "soft" and "very soft" water, which is a performance never achieved to date. From 70 m3, an electrode is saved while having better ionization thanks to the good balance of ion emissions.

 The electrodes can be arranged in a circle (that is to say according to a virtual polygon) and provide at least one other inside the circle.

 Generally, a spacing of forty millimeters is provided between the axes of the electrodes, which currently have a diameter of twenty millimeters, which gives a minimum spacing when the electrodes are new of twenty millimeters measured linearly from surface to surface. The electrodes must be replaced when their diameter is no more than approximately five millimeters, their spacing then being approximately thirty five millimeters, which is almost twice the original spacing.

Claims (6)

 1- Device for permanent treatment of a liquid such as water with a view to its purification by in situ emission of metal ions from electrodes immersed in a current of this liquid and brought to different electrical potentials, characterized in that it comprises at least one ionization vessel for at least three electrodes (250-251-252).  2- Device according to claim t, characterized in that it comprises at least one ionization vessel for an odd number of electrodes (250-251-252, 253-254-255-256-257).  3- Device according to claim 1, characterized in that the electrodes (250-251-252 and 253 to 257) are arranged in a single line.  4- Device according to claim 1, characterized in that the electrodes (250-251-252 and 253-254-255-259-256-255-258 and 260-261262-263 and 270-271-272-273-274 -2753 are arranged at the vertices of a virtual polygon.  5- Device according to claim 1, characterized in that the electrodes (253-254-259-256-255-258) are staggered along at least two parallel lines.  6- Device according to claim 1, characterized in that the electrodes (260-261-262-263 and 270 to 275) are arranged in a virtual parallelogram.