EP0673717B1 - Process and apparatus with an automatic closed circuit for dirt free cleaning of monuments and buildings - Google Patents

Description

The problem of remedying deterioration and fouling monuments and buildings, provoked more and more by the air pollution, has been more or less resolved satisfactory by processes and facilities necessarily different, in relation to the diverse nature of pollutants and / or the attacked surface and / or at the affected depth.

Generally speaking, we are confronted with inlays black or dark gray consisting of salts resulting from the reaction of the building material with suspended acids in the air (acid rain) or with hydrocarbons (gas exhaust). And these inlays can adhere more or less tenaciously and deeply to the surface to be leveled.

We therefore used a wide range of processes (and facilities) - which range from simply spraying cold or superheated water, pressure jets of water or steam, or the use of acidic detergent solutions or pastes or basic, to a projection of sand soaked in water.

But these processes require for the cleaning the use of water, at least in the following (for example, acidic products or of course must be completely eliminated from surfaces treated by washing them with plenty of water). And the surface of the buildings having thus been soaked can put years to dry completely, being in this time exposed to frost cracking.

It is even possible, in the case that a facade is soaked with water covered with plaster, as gypsum (calcium sulfate) which it consists of permanently retains water and loses any consistency and / or allows moisture to enter the rooms.

In addition, in the case of the projection of sand, even soaked of water, we must note a more or less deep abrasion of the surface, which takes away its smooth and shiny state - a almost never acceptable deterioration.

It is for this reason that the use of sand for the repair of monuments and buildings is, or will soon be be, prohibited by the regulations of many countries.

The primary condition for restoring the surface in its primitive state is therefore not satisfied.

Another series of procedures does not, in fact, provide the use of water for scouring per se - being based on the projection of more or less fine sand not watered, or else on polishing with more or less rough sanders - but use, however, curtains of water spray in a certain measure, in order to prevent the emission of dust fouled in the ambient atmosphere, channeling them to bins or immediately to the sewers and the water table phreatic.

All these processes, and the respective facilities for implement, therefore only partially satisfy, or even not at all, on the other essential condition, and strictly protection of the environment.

a) ils excluent tout emploi d'eau, aussi bien dans le courant du ragréement qu'après (pour lavage de détergents ou autre) et

b) prévoient que l'exécution du ragrément soit à cycle fermé c'est-à-dire que les moyens employés - une poudre et l'air - soient réutilisés, et de façon continue, et

c) que les déchets de crasse aussi bien que l'air qu'ils entraínent soient canalisés vers un conteneur de détritus étanche et éliminés conformément aux normes pour la protection de l'environnement.

The process and the installation relating thereto which are the subject of this patent application make it possible to smooth the surface of a monument or a building to its original condition while avoiding the aforementioned drawbacks, and this because :

a) they exclude any use of water, both in the course of the stain and after (for washing detergents or other) and

b) provide that the execution of the approval is a closed cycle, that is to say that the means used - powder and air - are reused, and continuously, and

c) that dirt as well as the air it entrains is channeled to a sealed trash container and disposed of in accordance with standards for environmental protection.

Both the process and the installation also present other important advantages of the invention, which will be highlighted in the following description.

1. L'utilisation d'une poudre très tendre et à grains extrèmement menus ( d'un diamètre de 10 - 25 µm ) ;

2. La projection sous pression de la poudre sur la surface du bâtiment qui présente un encrassement et/ou des incrustations. L'opérateur effectue la projection à l'intérieur d'une cabine de ragréement étanche - dont un côté est ouvert vers la surface à ragréer et bordé avec un soufflet d'étanchement - en se servant d'un injecteur de ragréement à air comprimé, qui est alimenté par un compresseur situé hors de la cabine.
   Le ragréement est opéré dans les conditions suivantes :

a) la poudre est utilisée dans son état sec,

b) la projection s'effectue vers le bas, dans une direction qui forme un angle aigu très petit (normalement 10^o - 20^o) avec la surface à ragréer, donc quasi verticalement,

c) la projection est réglée par l'opérateur en dépendance de la nature de la surface à ragréer ainsi que du genre et de l'adhérence de l'encrassement, puisqu'il peut modifier

• l'angle aigu plus ou moins petit que l'injecteur de ragréement forme avec la surface,
• la distance de cet injecteur de la surface et
• la pression à laquelle la poudre est projetée.

Dans ces conditions :

• le particules séparées possèdent une énergie cinétique minimale, non susceptible de désagréger le mortier liant les matériaux de construction, et
• chaque particule, très tendre, peut se déformer, et n'exerce une action abrasive - justement de par son dégré de dureté très bas - que là où l'opérateur la conditionne à cet effet.

   Il est d'ailleurs facile de régler les facteurs indiqués sub 2.c. dans une combinaison telle qu'une " action de frottement " plus ou moins prononcée permette d'optimiser le ragréement - aussi bien par un léger encrassement que par des incrustations tenaces - tout en évitant les inconvénients signalés au début ;

3. L'évacuation du mélange de déchets crasseux et de poudre rejaillissant de la surface ragréée. Cette évacuation est effectuée par des flux d'air comprimé, qui sont insufflés dans la cabine par le compresseur susmentionné ( alimentant aussi l'injecteur de ragrément ) et qui convergent vers l'une de plusieurs fentes d'évacuation situées près du bord avant du plancher. Ce sont là :

a) un premier flux d'air comprimé que l'un de plusieurs injecteurs d'évacuation supérieurs, alignés près du bord avant du plafond de la cabine et alimentés par le compresseur, projette en éventail, parallèlement à la surface ragréée, vers l'une fente d'évacuation susdite,

b) un deuxième flux d'air comprimé que l'un de plusieurs injecteurs d'évacuation inférieurs, alignés près du bord arrière du plancher de la cabine et alimentés par le compresseur, projette en éventail, parallèlement au plancher, vers la même fente d'évacuation et

c) une paire de flux d'air comprimé que deux injecteurs d'évacuation placés à mi-hauteur près des bords avant des parois latérales de la cabine et alimentés par le compresseur projettent en éventail, parallèlement à la surface ragréée, l'un vers l'autre. Le premier flux d'air d'évacuation, vertical, est certes susceptible, à lui seul, d'entraíner vers une fente d'évacuation tout le mélange déchets crasseux / poudre rejaillissant d'une surface ragréée lisse. Mais une surface lisse - compte tenu des accoudoirs et encadrements de fenêtres, des balcons, d'ornamentations saillantes etc. - représente plutôt une exception.Comme il y a donc lieu de prévoir que des tourbillons provoquent parfois un plus ou moins abondant rejaillissement du mélange dans toutes les directions, il est clair que le deuxième flux d'air d'évacuation, horizontal, a une fonction essentielle : celle de ramener vers la fente correspondante (la plus proche) cette partie de matériaux qui aurait échappé à l'action du flux d'air vertical et se serait déposée sur le plancher. Quant à la paire de flux d'air d'évacuation transversaux, ils ont une fonction de barrage : ils empêchent, en effet - également dans le cas d'éléments de façade saillants - que des déchets crasseux et de la poudre, rejaillissant dans des directions quelconques, ne s'échappent vers l'extérieur.Néanmoins, dans un souci de fournir un complément - ou, le cas échéant, un remplacement - de l'un et/ou de l'autre flux d'évacuation, l'invention prévoit

d) une évacuation d'appoint du mélange déchets / poudre, et met à la disposition de l'opérateur un moyen ad hoc : un injecteur d'évacuation mobile, joint de façon réglable à l'injecteur de ragréement.

Cet injecteur mobile est alimenté - en parallèle avec l'injecteur de ragréement et avec les injecteurs d'évacuation produisant les flux d'air vertical, horizontal et trasversaux - par le compresseur d'alimentation générale.Il a une forme opportunément allongée dans le sens horizontal et est fixé à l'injecteur de ragréement au-dessus et à une certaine distance de celui-ci ; son jet d'air comprimé est ainsi projecté au-dessus de, et quasi parallèlement à, la poudre ragréant la surface encrassée.( L'injecteur mobile peut, par exemple, être solidaire de l'extrémité d'un tube télescopique qui est normalment disposé dans une direction parallèle à l'injecteur, mais dont l'angle est réglable dans une certaine mesure - de même que sa distance de la surface ragréée et que la pression de l'air d'évacuation. )Dans ces conditions, on comprend que l'opérateur est à même de diriger le jet d'air d'évacuation mobile de la manière la plus efficace : le ragréement procède, littéralement, de conserve avec l'évacuation complète du mélange déchets / poudre vers la fente du plancher la plus proche grâce à la simultanéité de :

a) le jet d'air de l'injecteur de ragréement, dirigé par l'opérateur sur la surface à ragréer,

b) le jet d'air, vertical, de l'un injecteur d'évacuation supérieur, dirigé parallèlement à la surface à ragréer,

c) le jet d'air, horizontal, de l'un injecteur d'évacuation inférieur, dirigé parallèlement au plancher,

d) la paire de jets d'air, transversaux, des injecteurs d'évacuation latéraux, dirigés parallèlement à la surface à ragréer et

e) le jet d'air de l'injecteur mobile, opportunément dirigé de conserve avec le jet d'air de l'injecteur de ragréement - si l'opérateur y a recours ;

4. La convection du mélange déchets crasseux / poudre le long de plusieurs conduits de convection qui sont aménagés au-dessous du plancher de la cabine et, qui convergent vers un séparateur à labyrinthe pourvu de filtre d'air. Cette convection est effectuée par l'air insufflé, parallèlement au plancher, par l'un de plusieurs injecteurs de convection situés un peu en aval des fentes d'évacuation respectives. Les injecteurs de convection sont aussi alimentés - comme les jets d'air énumérés sub 3.a.,b.,c.,d.,e. - par le compresseur d'alimentation général ;

5. La séparation dans le séparateur à labyrinthe avec filtre d'air de :

a) les déchets crasseux : ils sont arrêtés dans le séparateur - avec une petite quantité de la poudre de ragréement et une petite partie de l'air d'évacuation, qui étaient entraínés avec - et sont ensuite dirigés vers un tuyau d'élimination descendant, qui les emmène, par simple gravité, dans un containeur de détritus étanche,

b) la poudre de ragréement: la majeure partie de la poudre traverse le séparateur à labyrinthe et est arrêtée par le filtre d'air assorti à celui-ci. Elle s'accumule alors dans un récipient à poudre de ragréement, adjacent au séparateur, où se trouve déjà de la poudre d'appoint,

c) l'air ( de ragréement, d'évacuation et de convection ) : il traverse le séparateur, où une petite partie en est entraínée par les déchets crasseux, tandis que tout le reste de l'air parvient - avec la poudre de ragréement - au filtre à air. Il tend continuellement à s'en dégager - du fait qu'il se trouve encore sous une certaine pression - et un conduit d'acheminement l'emmène alors, sans aucune trace de déchets crasseux ou de poudre, jusqu'à l'orifice d'admission de l'injecteur de ragréement.

6. Le recyclage de :

b'.) la poudre de ragréement évacuée : s'étant accumulée, dans sa quasi-totalité, dans le récipient à poudre de ragréement du séparateur, la poudre est continuellement acheminée ( avec la poudre d'appoint ) vers l'injecteur de ragréement. Ce, par effet de l'aspiration qui est produite dans l'injecteur par un flux d'air comprimé alimenté par le compresseur - justement pour entraíner la poudre et la projeter vers la surface encrassée,

c'. l'air de ragréement, d'évacuation et de convection: il est canalisé, de façon continue, dans un conduit d'acheminement qui l'amène jusqu'au même orifice d'admission de l'injecteur de ragréement par où passe la poudre de ragréement, avec laquelle il est recyclé ;

7. L'élimination dans le conteneur de détritus étanche de :

• le déchets crasseux y emmenés par le tuyau d'élimination descendant du séparateur,
• la petite quantité de poudre de ragréement entraínée par ces déchets crasseux, et
• la petite partie d'air d'évacuation également entraínée par ces déchets crasseux.

The process includes the following operations:

1. The use of a very soft powder with extremely small grains (with a diameter of 10 - 25 µm);

2. The spraying of the powder under pressure onto the surface of the building, which is fouled and / or encrusted. The operator performs the spraying inside a sealed leveling cabin - one side of which is open towards the surface to be leveled and bordered with a sealing bellows - using a compressed air leveling injector, which is powered by a compressor located outside the cabin.
The leveling is carried out under the following conditions:

a) the powder is used in its dry state,

b) the projection is made downward, in a direction which forms a very small acute angle (normally 10 ^o - 20 ^o ) with the surface to be leveled, therefore almost vertically,

c) the projection is adjusted by the operator depending on the nature of the surface to be leveled as well as the type and adhesion of fouling, since it can modify

• the more or less small acute angle that the leveling injector forms with the surface,
• the distance of this injector from the surface and
• the pressure at which the powder is sprayed.

In these conditions :

• the separated particles have a minimum kinetic energy, not capable of disintegrating the mortar binding the building materials, and
• each very tender particle can deform, and only exerts an abrasive action - precisely because of its very low degree of hardness - where the operator conditions it for this purpose.

It is also easy to adjust the factors indicated in 2.c. in a combination such as a more or less pronounced "rubbing action" makes it possible to optimize the leveling - both by light fouling and by stubborn encrustations - while avoiding the drawbacks mentioned at the start;

3. The evacuation of the mixture of filthy waste and powder spurting from the leveled surface. This evacuation is carried out by compressed air flows, which are blown into the cabin by the aforementioned compressor (also supplying the embellishment injector) and which converge towards one of several evacuation slots located near the front edge of the floor. These are there:

a) a first flow of compressed air which one of several upper exhaust injectors, aligned near the front edge of the cabin ceiling and supplied by the compressor, projects in a fan shape, parallel to the leveled surface, towards the a said evacuation slot,

b) a second flow of compressed air which one of several lower exhaust injectors, aligned near the rear edge of the cabin floor and supplied by the compressor, projects in a fan shape, parallel to the floor, towards the same slot d evacuation and

c) a pair of compressed air flows which two exhaust injectors placed at mid-height near the front edges of the side walls of the cabin and fed by the compressor fan project, parallel to the leveled surface, one towards the other. The first exhaust air flow, vertical, is certainly likely, in itself, to drive towards a discharge slot all the grimy waste / powder mixture spurting from a smooth smooth surface. But a smooth surface - considering the armrests and window frames, balconies, protruding ornamentation etc. - rather represents an exception. As it is therefore to be expected that vortices sometimes cause a more or less abundant spurting of the mixture in all directions, it is clear that the second exhaust air flow, horizontal, has a essential function: that of bringing back towards the corresponding (closest) slot this part of materials which would have escaped the action of the vertical air flow and would have deposited on the floor. As for the pair of transverse exhaust air flows, they have a barrier function: they prevent, in fact - also in the case of projecting facade elements - that grimy waste and powder, spurting out in directions, do not escape to the outside. Nevertheless, in order to provide a complement - or, if necessary, a replacement - of one and / or the other discharge flow, the invention plans

d) an additional evacuation of the waste / powder mixture, and makes available to the operator an ad hoc means: a mobile evacuation injector, which is adjustable to the leveling injector.

This mobile injector is supplied - in parallel with the leveling injector and with the exhaust injectors producing vertical, horizontal and transverse air flows - by the general supply compressor. It has a conveniently elongated shape in the direction horizontal and is fixed to the leveling injector above and at a certain distance therefrom; its jet of compressed air is thus projected above, and almost parallel to, the powder leveling the dirty surface. (The mobile injector can, for example, be integral with the end of a telescopic tube which is normally arranged in a direction parallel to the injector, but whose angle is adjustable to a certain extent - as well as its distance from the leveled surface and the pressure of the exhaust air.) Under these conditions, we understand that the operator is able to direct the mobile exhaust air jet in the most efficient way: the leveling proceeds, literally, in a can with the complete evacuation of the waste / powder mixture towards the most slotted floor slot close thanks to the simultaneity of:

a) the air jet from the leveling injector, directed by the operator on the surface to be leveled,

b) the vertical air jet from the upper evacuation injector, directed parallel to the surface to be leveled,

c) the horizontal air jet from one lower exhaust injector, directed parallel to the floor,

d) the pair of transverse air jets, of the lateral exhaust injectors, directed parallel to the surface to be leveled and

e) the air jet from the mobile injector, conveniently directed in a can with the air jet from the leveling injector - if the operator uses it;

4. The convection of the filthy waste / powder mixture along several convection conduits which are arranged below the cabin floor and which converge towards a labyrinth separator provided with air filter. This convection is carried out by the blown air, parallel to the floor, by one of several convection injectors located a little downstream of the respective evacuation slots. Convection injectors are also supplied - like the air jets listed under 3.a., b., C., D., E. - by the general supply compressor;

5. The separation in the labyrinth separator with air filter of:

a) filthy waste: they are stopped in the separator - with a small quantity of the powder of leveling and a small part of the exhaust air, which were entrained with - and are then directed towards a downward elimination pipe , which takes them, by simple gravity, into a sealed trash container,

b) patching powder: most of the powder passes through the labyrinth separator and is stopped by the air filter associated with it. It then accumulates in a leveling powder container, adjacent to the separator, where there is already make-up powder,

c) air (for leveling, evacuation and convection): it passes through the separator, where a small part is entrained by the filthy waste, while all the rest of the air arrives - with the leveling powder - the air filter. It continually tends to emerge from it - because it is still under a certain pressure - and a routing conduit then takes it, without any trace of grubby waste or powder, to the orifice admission of the leveling injector.

6. Recycling of:

b '.) the leveling powder discharged: having accumulated, almost entirely, in the leveling powder container of the separator, the powder is continuously conveyed (with the make-up powder) to the leveling injector . This, by effect of the suction which is produced in the injector by a flow of compressed air supplied by the compressor - precisely to entrain the powder and to project it towards the dirty surface,

vs'. the air for stirring, evacuation and convection: it is continuously channeled in a conveying duct which brings it to the same inlet orifice of the stirring injector through which the powder passes of refreshing, with which it is recycled;

7. Disposal in the sealed trash container of:

• the filthy waste taken there by the elimination pipe coming down from the separator,
• the small amount of coarse powder entrained by this filthy waste, and
• the small part of the exhaust air also entrained by this filthy waste.

1. Un ragréement parfait de n'importe quelle surface, encrassée n'importe comment, grâce au principe d'une action frottante de la poudre - mis en oeuvre en faisant former à l'injecteur de ragréement un angle aigu avec la surface - cette action étant favorisée par la possibilité de régler, d'une part, la distance de l'injecteur de la surface et, d'autre part, la pression de la poudre. Ce sont là trois facteurs qui écartent tout danger soit de désagréger le mortier liant les matériaux de construction, soit de rayer ou mater la surface ragréée. Cela, d'une manière antithétique à l'usage, généralement suivi, d'une projection de sable orthogonalement à la surface. Cet usage - que l'on croit, à tort, permettre un résultat un peu plus rapide - est inévitablement délétère et pour l'apparence de la surface ( rayage, décoloration, matage etc. ) et pour sa consistance elle-même ( mortier de liaison ). Ce, évidemment, en raison de l'énergie cynétique des grains de sable, qui doit être intégralement absorbée par les matériaux ( de la surface et de la construction ) avec donc un effet de choc ;

2. Une évacuation rationnelle - économique et non polluante - des déchets de crasse mélangés à la poudre de ragréement, qui est effectuée selon un principe diamétralement opposé à celui, parfois suivi, de l'aspiration de ce mélange : le principe de l'évacuation par air comprimé visée.
   L'évacuation effectuée conformément à ce principe ne demande, en effet, qu'une petite fraction de l'énergie qu'exigeait la dépression sous laquelle toute la cabine devait être mise afin que le mélange de déchets crasseux et sable puisse être aspiré par d'énormes ventilateurs aspirants. Selon l'invention, et comme décrit ci-dessus sub 3., l'évacuation est accomplie par des flux d'air comprimé en éventail, qui encadrent le côté ouvert de la cabine et qui sont sélectivement dirigés vers cette partie limitée de la surface à ragréer qui est successivement visée par la projection de poudre. Ces flux peuvent d'ailleurs être intégrés par un flux d'appoint produit par un injecteur d'évacuation mobile, qui est solidaire de l'injecteur de ragréement et qui vise exactement la petite partie de surface frottée par la poudre.
   Le caractère économique de l'évacuation selon ce principe est évident : seulement un très petit compresseur est suffisant pour évacuer parfaitement déchets et poudre. De même, toute cette importante installation qui devait assurer le transport et les filtrage successifs du mélange aspiré, est maintenant réduite au minimum : elle se limite au séparateur à labyrinthe avec filtre d'air, de dimensions très modestes, dont le fonctionnement a été décrit ci-dessus sub 5.;

3. Le fonctionnement automatique de l'installation selon l'invention, qui augmente drastiquement le caractère économique du procédé. En effet :

a) il réduit fortement le temps demandé par le ragréement. Ce, du fait qu'un système d'interrupteurs de contact, disposés au-dessous du plancher de la cabine, fonctionne de telle manière que, lorsque l'opérateur met, ou maintient, en action l'injecteur de ragréement, le système ferme les séries de circuits l'une après l'autre, au fur et à mesure qu'elles viennent se trouver vis-à-vis de la partie de surface à ragréer. De ce fait, en même temps que l'injecteur de ragréement, sont actionnés automatiquement et simultanément l'un injecteur d'évacuation supérieur, l'un injecteur d'évacuation inférieur, les injecteurs d'évacuation latéraux, l'injecteur d'évacuation mobile, si enclenché, et l'un injecteur de convection.
   L'opérateur est ainsi déchargé de toute opération ayant trait à l'évacuation des mélanges successifs de déchets crasseux et poudre, à leur convection respective vers le séparateur à labyrinthe avec filtre d'air et à la séparation des déchets crasseux, de la poudre et de l'air les entraínant.
   L'opérateur est également déchergé des opérations afférentes, d'une part, à l'éloignement des déchets crasseux et, d'autre part, au recyclage de la poudre résiduelle et de l'air sortant du séparateur, puisque aussi toutes ces opérations s'effectuent, et de manière optimale, automatiquement.
   Un autre avantage, économiquement non négligeable, du fonctionnement automatique de l'installation réside en ce que

b) il met à l'abri de toute fausse manoeuvre de la part de l'opérateur, qui serait susceptible d'endommager le matériel et de provoquer un arrêt, même temporaire, du travail ;

4. ' Last not least ' : Le procédé conforme à l'invention

a) qui prévoit un ragréement exécuté à circuit fermé et

b) qui exclut tout emploi d'eau, soit dans le courant de l'opération, soit dans la suite

présente une garantie absolue dans le cadre de la protection de l'environnement - et de la construction ragréée elle-même - pour les raisons suivantes :

a₁) il n'y a pas emploi de sable, qui exercerait une action abrasive, mais d'une poudre à grains extrèmement menus, la mieux indiquée pour ragréer une surface sans la rayer, et

a₂) cette poudre n'est pas envoyée, pendant le travail, dans l'atmosphère ambiante, mais est recyclée,

a₃) il n'y a pas de déchets crasseux amenés vers les égouts - puisqu'ils sont, par contre, conduit dans un conteneur étanche, pour être ensuite éliminés selon les normes en vigueur,

a₄) il n'y a pas de sortie d'air dans l'atmosphère ambiante, avec des particules de crasse plus menues et de la poudre de ragréement entraínées avec - puisque l'air est filtré et recyclé,

b₁) il n'y a pas d'eau crasseuse versée dans les égouts (et aboutissant à la nappe phréatique) et

b₂) il n'y a pas d'eau pulvérisée qui imbibe la surface ragréée - ou qui soit transportée par l'air sur les constructions adjacentes ( avec les fâcheuses conséquences mentionnées au début ) .

   Une cabine permettant de réaliser l'invention peut être conçue d'une manière connue quelconque : néanmoins, dans un but de réduire, pour des raisons évidentes, son poids, on peut envisager une cabine consistant, grosso-modo, dans des plaques d'un matériau plastique, de préférence transparent ou semi-transparent, ou de contre-plaqué. Ces plaques sont rendues mutuellement solidaires par une charpente, par exemple, de profilés en aluminium.
   Une cabine de ce genre, ou d'un genre semblable, peut facilement être fixée, aussi de manière connue, à l'extrémité du bras d'une grue de construction et déplacée selon la hauteur et la longueur d'un monument ou d'un bâtiment.
   Cependant - si l'on tient compte de la hauteur relativement grande de nombre de monuments (églises, tours, clochers etc.) et de bâtiments (grands palais, gratte-ciels ou autres), dont le ragréement nécessiterait l'emploi, très onéreux, d'une grue géante ( avec une hauteur de levage de 50 - 60 m ou plus)-on peut, dans la plupart des cas, avoir recours à d'autres solutions.
   Selon une première alternative, la cabine selon l'invention est fixée sur une nacelle du commerce ( par exemple celle de la Fig. 1 ), levée par un système de suspension que l''homme de l'art' peut opportunément choisir également dans la gamme du commerce : à titre d'exemple, dans le cas d'une surface à ragréer présentant des saillies importantes (comme des balcons, des loges proéminent ou autre), une poutre télescopique mobile, comme celle de la Fig. 2, serait particulièrement indiquée.
   On peut, d'autre part,préférer un système rendant le ragréement plus continu et uniforme, et l'invention prévoit alors que la cabine de ragréement puisse librement se déplacer sur une longue plate-forme de travail.
   La plate-forme est alors opportunément constituée par plusieurs modules en aluminium de longueurs différentes (comme celle de la Fig. 3), dont l'assemblage s'adapte bien à la configuration d'un monument ou d'un bâtiment.
   Conformément à l'invention, la cabine, d'une part, est supportée par un châssis indépendant pourvu de roulettes - ou bien des roulettes sont montées sur son propre châssis.
   Au plancher de la plate-forme, d'autre part, sont fixés rigidement deux rails longitudinaux - qui assurent, en plus du guidage des roulettes, un renforcement de la plate-forme elle-même, soumise à une charge variable avec la position de la cabine.
   La suspension peut se faire, aussi dans ce cas, à l'aide de deux ou plusieurs poutres télescopiques mobiles, celles-ci étant pourvues de treuils à câble de longueur illimitée (pratiquement au-delà de 100 m) (v. Fig. 4).
   Selon encore une autre solution, la plate-forme munie de rails, sur laquelle la cabine conforme à l'invention se déplace sur ses roulettes, peut monter ou descendre, de façon autonome, le long d'un seul mât ou le long de deux mâts (voir les Fig. 5 et 6), qui sont montés sur une remorque tractée.
   Toutes les formes de réalisation décrites ci-dessus - à titre d'exemple - présentent l'avantage, relativement à celle prévoyant l'emploi d'une grue géante, d'un investissement de loin plus réduit, voire d'un autre ordre de grandeur.This elimination is obviously carried out by following the standards emitted, in the various countries, by the authorities responsible for the protection of the environment.
A careful examination of the above description makes it possible to confirm that the process in accordance with the invention actually achieves the results and the advantages announced, namely:

1. Perfect leveling of any surface, clogged anyway, thanks to the principle of a rubbing action of the powder - implemented by making the leveling injector form an acute angle with the surface - this action being favored by the possibility of regulating, on the one hand, the distance of the injector from the surface and, on the other hand, the pressure of the powder. These are three factors which rule out any danger either of breaking up the mortar binding the building materials, or of scratching or matting the leveled surface. This, in an antithetical way to the use, generally followed, of a projection of sand orthogonally on the surface. This use - which we believe, wrongly, to allow a slightly faster result - is inevitably deleterious and for the appearance of the surface (scratching, discoloration, matting etc.) and for its consistency itself (mortar of liaison). This, obviously, due to the cynetic energy of the grains of sand, which must be completely absorbed by the materials (of the surface and of the construction) with therefore a shock effect;

2. A rational - economic and non-polluting - disposal of grime waste mixed with the coarse powder, which is carried out according to a principle diametrically opposite to that, sometimes followed, of the suction of this mixture: the principle of evacuation by compressed air aimed.
The evacuation carried out in accordance with this principle requires, in fact, only a small fraction of the energy required by the depression under which the whole cabin had to be put so that the mixture of grimy waste and sand can be sucked up by d 'huge suction fans. According to the invention, and as described above under 3., the evacuation is accomplished by fan-shaped compressed air flows, which frame the open side of the cabin and which are selectively directed towards this limited part of the surface to be smoothed which is successively targeted by the projection of powder. These flows can also be integrated by a make-up flow produced by a mobile evacuation injector, which is integral with the leveling injector and which targets exactly the small part of the surface rubbed by the powder.
The economic character of the evacuation according to this principle is obvious: only a very small compressor is sufficient to evacuate waste and powder perfectly. Likewise, this entire important installation which was to ensure the successive transport and filtering of the aspirated mixture, is now reduced to a minimum: it is limited to the labyrinth separator with air filter, of very modest dimensions, the operation of which has been described. above sub 5 .;

3. The automatic operation of the installation according to the invention, which drastically increases the economic nature of the process. Indeed :

a) it greatly reduces the time required for patching. This is due to the fact that a system of contact switches, arranged below the cabin floor, operates in such a way that, when the operator activates or maintains the leveling injector in action, the system closes the series of circuits one after the other, as they come to be opposite the surface part to be leveled. Therefore, at the same time as the leveling injector, the upper evacuation injector, the lower evacuation injector, the lateral evacuation injectors, the evacuation injector are actuated automatically and simultaneously. mobile, if engaged, and one convection injector.
The operator is thus relieved of all operations relating to the removal of successive mixtures of grime and powder waste, their respective convection to the labyrinth separator with air filter and the separation of grime waste, powder and air entraining them.
The operator is also relieved of the operations relating, on the one hand, to the removal of filthy waste and, on the other hand, to the recycling of the residual powder and of the air leaving the separator, since also all these operations are '' perform, and optimally, automatically.
Another economically significant advantage of the automatic operation of the installation is that

b) it protects against any false maneuver on the part of the operator, which would be likely to damage the equipment and cause work to be stopped, even temporarily;

4. 'Last not least': The process according to the invention

a) which provides for a patching carried out with a closed circuit and

b) which excludes any use of water, either during the operation or subsequently

presents an absolute guarantee in the context of environmental protection - and of the repaired construction itself - for the following reasons:

a ₁ ) there is no use of sand, which would exert an abrasive action, but of an extremely small grain powder, best suited for leveling a surface without scratching it, and

a ₂ ) this powder is not sent, during work, to the ambient atmosphere, but is recycled,

a ₃ ) there is no filthy waste brought to the sewers - since they are, on the other hand, led into a sealed container, to be then disposed of according to the standards in force,

a ₄ ) there is no air outlet in the ambient atmosphere, with smaller particles of grime and enticing powder entrained with - since the air is filtered and recycled,

b ₁ ) there is no filthy water poured into the sewers (and ending in the water table) and

b ₂ ) there is no water spray which soaks the smoothed surface - or which is transported by air on adjacent constructions (with the unfortunate consequences mentioned at the beginning).

A cabin making it possible to carry out the invention can be designed in any known manner: nevertheless, with the aim of reducing, for obvious reasons, its weight, it is possible to envisage a cabin consisting, roughly speaking, in plates of a plastic material, preferably transparent or semi-transparent, or plywood. These plates are made mutually integral by a frame, for example, of aluminum profiles.
A cabin of this kind, or of a similar kind, can easily be fixed, also in a known manner, to the end of the arm of a construction crane and moved according to the height and the length of a monument or of a building.
However - if we take into account the relatively large height of a number of monuments (churches, towers, bell towers etc.) and buildings (large palaces, skyscrapers or others), the cost of which would require the use, very expensive , a giant crane (with a lifting height of 50 - 60 m or more) - in most cases, other solutions can be used.
According to a first alternative, the cabin according to the invention is fixed to a commercial nacelle (for example that of FIG. 1), lifted by a suspension system which the skilled person can conveniently also choose from. the range of the trade: for example, in the case of a surface to be leveled presenting significant projections (like balconies, prominent lodges or other), a mobile telescopic beam, like that of FIG. 2, would be particularly indicated.
We can, on the other hand, prefer a system making the patching more continuous and uniform, and the invention then provides that the patching cabin can move freely on a long working platform.
The platform is then conveniently made up of several aluminum modules of different lengths (like the one in Fig. 3), the assembly of which adapts well to the configuration of a monument or building.
According to the invention, the cabin, on the one hand, is supported by an independent chassis provided with casters - or else castors are mounted on its own chassis.
On the other hand, two longitudinal rails are rigidly attached to the platform floor - which, in addition to guiding the rollers, reinforce the platform itself, subjected to a variable load with the position of the cabin.
The suspension can be done, also in this case, using two or more mobile telescopic beams, these being provided with cable winches of unlimited length (practically beyond 100 m) (see Fig. 4 ).
According to yet another solution, the platform provided with rails, on which the cabin according to the invention moves on its casters, can go up or down, independently, along a single mast or along two masts (see Figs. 5 and 6), which are mounted on a towed trailer.
All the embodiments described above - by way of example - have the advantage, relatively to that providing for the use of a giant crane, of a much smaller investment, or even of another order of greatness.

Claims (7)

1. A method for the cleaning of soiled monuments and buildings, comprising projecting against the surface thereof a granular material by compressed air and inside a cabin, wherein :

   the projected material is a powder consisting of utmost tiny and very soft granules 10 - 25 µm in diameter, said powder being used in dry condition,

   said powder is projected on to said surface by a compressed air cleaning injector being fed by a compressor placed outside the cabin,

   the powder is normally projected in a downward almost vertical direction,

   the powder is projected while modifying the direction, distance and pressure of the jet depending on the different nature of the surface and on the nature and adherence of the soiled matters turning up as the cleaning proceeds, so that the powder exerts on the surfaces a rubbing action with an optimal cleaning,

   the evacuation from the cabin of the soiled debris mixed up with powder spurting back from the cleaned surface is performed through a first adjustable, vertical, air flow that the one of several upper compressed air evacuating injectors, in a line near the fore-edge of the cabin ceiling and being fed by said compressor, projects fan-wise in a parallel direction with the cleaned surface and towards the one of several evacuating slots in a line at a short distance from the fore-edge of the floor, through a second adjustable, horizontal, air flow that the one of several lower compressed air evacuating injectors, in a line near the back-edge of the floor and being fed by the compressor, projects fan-wise in a parallel direction with the floor and towards said one evacuating slot, and through a pair of adjustable, transversal, air flows that two or more lateral compressed air evacuating injectors, being placed half-way up near the fore-edge of the cabin side walls and fed by the compressor, project fan-wise, in a parallel direction with the cleaned surface, towards one another,

   the evacuation of soiled debris mixed up with powder from the cabin is apt to be completed, in the case of soiled surfaces jutting out, through an additional adjustable compressed air flow that a movable evacuation injector, placed at a short distance over the cleaning injector and joined therewith and fed by the compressor, projects fan-wise in a parallel direction with said jutting surface,

   the soiled debris mixed up with powder, swept along by said vertical, horizontal, transversal and movable, if provided, flows, gets through the one evacuating slot into the one of several conveying ducts arranged below the cabin floor, is swept along with the air flow that the one of several conveying injectors, provided shortly downstream relatively to the respective evacuating slots and fed by the compressor, projects in said conveying duct in a parallel direction with the cabin floor and thus is driven towards a separator with air filter, which is located outside the cabin,

   in said separator the soiled debris are separated from the major part of the powder and conveyed towards a downward eliminating pipe, which conducts them into a tight debris container,

   all the residual powder is captured by the air filter and collected into a powder container, adjacent to the separator,

   all the residual powder, having collected in said powder container, is reused by mixing therewith a small quantity of topping-up powder, provided in the same container, and by being sucked therefrom towards the cleaning injector by the compressed air flow supplied by the compressor,

   the air used in the cleaning, the evacuating and the conveying steps, not containing any trace more of soiled debris and powder, is continuously conducted towards the cleaning injector, where it is reused together with the air sent by the compressor,

   the system of contact interrupters, arranged below the cabin floor, functions in such a way that, when the operator starts, or keeps, the cleaning injector working, the system closes the circuit series one after another, as they turn up opposite the surface portion to be cleaned, thus automatically actuating, simultaneously with the cleaning injector, the one upper evacuating injector, the one lower evacuating injector, the lateral evacuating injectors, the movable evacuating injector, if connected, and the one convecting injector, whereby the operator is relieved of any operation referring to the evacuation of the successive mixings of soiled debris and powder, to the respective convection thereof towards the separator with air filter and to the separation of the soiled debris, of the powder and of the air carrying them along, and whereby he also is relieved of the operations referring, on the one hand, to the removal of the soiled debris and, on the other hand, to the reuse of the residual powder and of the air leaving the separator, since all these operations are carried out, at best, automatically,

   the soiled debris as also a very small portion of the cleaning powder and of the cleaning and evacuating air, having been collected into said tight debris container, are finally eliminated so as not to contaminate the environment in any way.
2. An apparatus for the cleaning of soiled monuments and buildings, comprising projecting against the surface thereof a granular material by compressed air and inside a cabin, wherein:

   the projected material is a powder consisting of utmost tiny and very soft granules 10 - 25 m in diameter, said powder being used in dry condition,

   said powder is projected on to said surface by a compressed air cleaning injector being fed by a compressor placed outside the cabin,

   the powder is normally projected in a downward almost vertical direction,

   the powder is projected while modifying the direction, distance and pressure of the jet depending on the different nature of the surface and on the nature and adherence of the soiled matters turning up as the cleaning proceeds, so that the powder exerts on the surfaces a rubbing action with an optimal cleaning,

   the evacuation from the cabin of the soiled debris mixed up with powder spurting back from the cleaned surface is performed through a first adjustable vertical air flow that the one of several upper compressed air evacuating injectors, in a line near the fore-edge of the cabin ceiling and being fed by said compressor, projects fan-wise in a parallel direction with the cleaned surface and towards the one of several evacuating slots in a line at a short distance from the fore-edge of the floor, through a second adjustable, horizontal air flow that the one of several lower compressed air evacuating injectors, in a line near the back-edge of the floor and being fed by the compressor, projects fan-wise in a parallel direction with the floor and towards said one evacuating slot and through a pair of adjustable, transversal air flows that two or more lateral compressed air evacuating injectors, being placed half-way up near the fore-edge of the cabin side walls and fed by the compressor, projects fan-wise, in a parallel direction with the cleaned surface, towards one another,

   the evacuation of soiled debris mixed up with powder from the cabin is apt to be completed, in the case of soiled surfaces jutting out, through an additional adjustable compressed air flow that a movable evacuation injector, placed at a short distance over the cleaning injector and joined therewith and fed by the compressor, projects fan-wise in a parallel direction with said jutting surface,

   the soiled debris mixed up with powder, swept along by said vertical, horizontal, transversal and movable, if provided, flows, gets through the one evacuating slot into the one of several conveying ducts arranged below the cabin floor, is swept along with the air flow that the one of several conveying injectors, located shortly downstream relatively to the respective evacuating slots and fed by the compressor, projects in said conveyind duct in a parallel direction with the cabin floor and thus is driven towards a separator with air filter, which is placed outside the cabin,

   in said separator the soiled debris are separated from the major part of the powder and conveyed towards a downward eliminating pipe, which conducts them into a tight debris container,

   all the residual powder is captured by the air filter and collected into a powder container, adjacent to the separator,

   all the residual powder, having collected in said powder container, is reused by mixing therewith a small quantity of topping-up powder, provided in the same container, and by being sucked therefrom towards the cleaning injector by the compressed air flow supplied by the compressor,

   the air used in the cleaning, the evacuating and the conveying steps, not containing any trace more of soiled debris and powder, is continuously conducted towards the cleaning injector, where it is reused together with the air sent by the compressor,

   the system of contact interrupters, arranged below the cabin floor, functions in such a way that, when the operator starts, or keeps, the cleaning injector working, the system closes the circuit series one after another, as they turn up opposite the surface portion to be cleaned, thus automatically actuating, simultaneously with the cleaning injector, the one upper evacuating injector, the one lower evacuating injector, the lateral evacuating injectors, the movable evacuating injector, if connected, and the one convecting injector, whereby the operator is releaved of any operation referring to the evacuation of the successive mixings of soiled debris and powder, to the respective convection thereof towards the separator with air filter and to the separation of the soiled debris, of the powder and of the air carrying them along, and whereby he also is relieved of the operations referring, on the one hand, to the removal of the soiled debris and, on the other hand, to the reuse of the residual powder and of the air leaving the separator, since all these operations are carried out, at best, automatically,

   the soiled debris as also a very small portion of the cleaning powder and of the cleaning and evacuating air, having been collected into said tight debris container, are finally eliminated so as not to contaminate the environment in any way.
3. An apparatus according to claim 2, wherein the cabin is mounted on a work platform and wherein said platform is fastened to the end of a building crane arm.
4. An apparatus according to claim 2, wherein the cabin is mounted on a work platform and wherein said platform hangs on cables whereby a hoisting system outside the platform is apt to move the latter in a vertical direction,
5. An apparatus according to claim 4, wherein said cables are stationary and wherein the platform is apt to move in a vertical direction along them in an autonomous way by means of a hoisting system mounted on the platform.
6. An apparatus according to claim 2, wherein the cabin is mounted on a work platform and wherein said platform is apt to move in a vertical direction along at least one hoisting mast in an autonomous way by means of a hoisting system mounted on the platform and wherein each hoisting mast is an integral part of a tractor-driven trailer.
7. An apparatus according to claims 3 to 6, wherein the cabin is apt to move along said platform.

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