FR2846322A1 - Descaling sanitary hot water circuits comprises passing the water through a cartridge containing granules comprising anionic activated silica compounds and oppositely polarized metallic particles - Google Patents

Abstract

Descaling sanitary hot water circuits at neutral pH comprises passing the water through a cartridge containing granules comprising anionic activated silica compounds and oppositely polarized metallic (especially iron oxide and manganese oxide) particles.

Description

The present invention relates to a method for rapidly descaling circuits

  domestic hot water in neutral pH environment.

  In many regions, raw water is loaded with salts, in particular calcium, and has a significant content of bi5 carbonate ions HC03- (hard or hard water) which, under certain conditions, in particular following a rise in temperature, tend to precipitate in the form of very poorly soluble calcium carbonate, which constitutes tartar.

  Consequently, the various individual or collective sanitary hot water circuits are very often scaled by deposits of calcium carbonate situated on the walls of the pipes and those of the water heaters or boilers.

  However, it is well known that these deposits of tartar are a source of major drawbacks: they tend in the long run to clog the canalizations and can to a large extent disturb the functioning of the

boilers or water heaters.

  Various means of removing tartar have already been proposed, such as, for example, treatment with acids, in particular hydrochloric acid, with ultrasound, or even mechanical treatments, in particular with rotary cutters.

  However, these are heavy and expensive treatments, the implementation of which is often inconvenient and which require an interruption in the service which is harmful to users. In addition, the use of acids represents a danger for pipelines due to the aggressiveness of these products.

  To overcome these drawbacks, a process has already been proposed in accordance with document FR-2 700 324 for descaling and decarbonating continuously raw calcareous water in a pH medium.

  neutral to prevent scale formation at the source.

  According to this known process, in a first step, the water to be treated is passed under pressure through a catalytic mass consisting of organometallic granules enclosed in a first cartridge so as to reduce the carbonates to carbon dioxide and to flocculate the limestone salts, and in a second step, the carbon dioxide / decarbonated water mixture is introduced into a second filter cartridge containing oxygenated active carbon so as to reprecipitate the gas

  carbonic into carbonates and to obtain purified water.

  This process has proved to be generally satisfactory, but nevertheless has a certain number of drawbacks linked in particular to the risk of a re-deposition of carbonates from carbon dioxide which is not evacuated in the case where the first cartridge containing the organometallic granules does not is not fully met.

  In addition, the mandatory presence of the second filter cartridge containing activated carbon increases to a large extent the cost of the process and the size of the installation allowing the implementation thereof, and moreover entails a risk of reduction. of pressure.

  The object of the present invention is to propose a rapid descaling process for domestic hot water circuits in a neutral pH medium so as to remedy these drawbacks.

  This process is characterized in that the flow of water circulating in the circuit to be treated is continuously passed through at least one cartridge containing a catalytic mass consisting of granules capable of rubbing against each other under the action of

flow of circulating water.

  According to the invention, it is possible to provide either a single cartridge, or, in particular for higher flow installations, several cartridges connected in series so as to increase the efficiency.

of the process.

  The granules constituting the catalytic mass are on the one hand essentially composed of anionic activated silica Si3Ol2 and contain on the other hand close metallic particles preferably particles of iron oxide and particles of polarized manganese oxide

  carrying electromagnetic charges of opposite sign.

  The presence of these metallic particles creates, within the catalytic mass, a dipolarization such as to cause the contraction of the calcium and the bicarbonates present in the flow of circulating water.

  essentially in collodal form, and as a result the formation of tiny germs of cationic calcium carbonate.

  During their formation and their passage through the catalytic mass, these germs attract small particles of silica which detach from the granules under the action of their friction against each other to form an anionic belt around these germs.

  This anionic belt is in turn capable of absorbing the cations encountered and in particular the pre-

  smells in the circulating water flow and on the walls of the circuit to be treated

by electromagnetic attraction.

  The germs thus coated with a silica belt indeed have a very strong sequestering power with respect to the calcium ions encountered.

  As a result, there is observed within the circulating water flow a rapid growth of very light expanded crystals following the continuous incorporation into their crystal structure, of calcium ions present in the water and of destabilized calcium ions formed on the walls

  pipes and boilers or water heaters of the circuit to be treated.

  These crystals, which originally had a hexagonal garnet-like structure with six hexes, lengthen during their development to

become orthorhombic.

  These very light and very expanded crystals cannot be deposited on the walls of the pipes and at the bottom of water heaters and boilers and can be removed by simple rinsing.

  The very particular efficiency of the process according to the invention is essentially linked to the very high proportion of silica

in the catalytic mass.

  This proportion in fact allows, thanks to the combined action 20 of metals of opposite sign, the instantaneous formation, around cationic germs, of anionic elements having a very strong sequestering power.

  vis-à-vis all the calcium ions encountered.

  We can thus quickly remove scale due to the continuous development of expanded and light non-encrusting crystals.

  According to the invention, the granules constituting the catalytic mass can advantageously contain between 80 and 95%, preferably

  about 90% activated silica in volumetric proportion.

  This very high proportion of silica allows rapid descaling without having to carry out a decarbonation process by the action of calcium chloride and dissolved oxygen such as

  described in the aforementioned document FR-2 700 324.

  In accordance with the invention, particularly satisfactory results have been obtained by using a catalytic mass having an apparent density of approximately 1.00 corresponding to a mass of approximately 1000 kg / m3 and being in the form of beads. hard and homogeneous regularly calibrated 1.5 to 2 mm in diameter.

  For example, catalytic beads can be used for this purpose, which are currently available on the market for the treatment of lime-free ferruginous waters and which essentially contain

  the following compounds: Fe2O3, CaCl2 and Ca3Mn2Si3Ol2.

  It should be noted that within the catalytic mass, the chlorides have the function only of allowing an accessory and not essential flocculation of the cations structured by the process according to the invention.

  According to another characteristic of the invention, the water flow is circulated from top to bottom in the cartridge containing the catalytic mass. The water flow can also without departing from the scope of the invention flow from bottom to top in the cartridge, in particular if the latter is installed in a filter body with central water inlet and at

exit by lateral diffusion.

  According to another characteristic of the invention, the cartridge 15 is only partially filled with granules, preferably approximately 2/3

of its height.

  This cartridge can advantageously have a configuration essentially similar to that of the first cartridge of the installation described in the document FR-2 700 324, that is to say be constituted by a cylinder in particular of a synthetic material having about 20 cm in height and 7 cm in diameter mounted on the middle part of a container, in particular of synthetic material, equipped with an upper lateral entry opening so as to define a sleeve at its periphery

receiving the water to be treated.

  Such a cartridge can thus be provided at its lower part with an inlet for the flow of circulating water and at its upper part with a central outlet.

  Going back up to exit through the central upper orifice of the cartridge, the flow of circulating water passes through the granules which can advantageously be wrapped in a very soft loosely meshed net allowing the free circulation of the granules and their

  friction against each other under the action of the water flow.

  It is therefore essential that the cartridge is not completely filled with granules.

Claims (1)

CLAIMS) Method for rapid descaling of domestic hot water circuits in neutral pH medium, characterized in that the flow of water circulating in the circuit to be treated is continuously passed through at least one cartridge containing a catalytic mass consisting of granules capable of rubbing against each other under the action of the flow of water in circulation, these granules being on the one hand essentially composed of anionic activated silica Si3Oi2 and ren10 closing on the other hand metallic particles , preferably iron oxide particles and polarized manganese oxide particles carrying electromagnetic charges of opposite sign, so as to cause, under the action of this dipolarization, the contraction of calcium and bicarbonates present in the flow of circulating water mainly in collodal form, and the formation of tiny cationic calcium carbonate germs likely to attract small silica particles detaching from the granules under the action of their friction against each other to form around these germs an anionic belt capable of in turn absorbing the calcium ions present in the flow of circulating water and on the walls of the circuit to be treated, by electromagnetic attraction. ) Method according to claim 1, characterized in that the granules constituting the catalytic mass contain between 80 and 95%, preferably about 90% of activated silica in volumetric proportion. ) Method according to any one of claims i and 2, characterized in that the granules constituting the catalytic mass are in the form of hard and homogeneous balls regularly calibrated 1.5 to 2 mm in diameter. ) Method according to any one of claims i to 3, characterized in that the catalytic mass has an apparent density of approximately 1.00 corresponding to a mass of approximately 1000 kg / m3. ) Method according to any one of claims 1 to 4, characterized in that the granules constituting the catalytic mass essentially contain the following compounds: Fe2O3, CaCl2 and Ca3Mn2Si3Ol2. ) Method according to any one of claims 1 to 5, characterized in that the water flow is circulated from top to bottom in the cartridge containing the catalytic mass. 10) Method according to any one of claims 1 to 5, characterized in that the water flow is circulated from bottom to top in the cartridge containing the catalytic mass. 15   8) Method according to any one of claims 1 to 7,   characterized in that the cartridge is only partially filled with granules, preferably about 2/3 of its height. 20