EP0384873A1 - Apparatus for cleaning building-walls - Google Patents

Abstract

The present invention relates to a process for mechanised cleaning of a building facade, characterised in that it consists in projecting over the facade, substantially perpendicularly to the latter and within a confined space corresponding to the surface to be cleaned, at least one incident flux of a cleaning agent, according to a rotary motion which is combined with a second movement which is permanently to-and-fro according to a trajectory substantially parallel to the facade, and in repeating these operations along the facade. <IMAGE>

Description

The present invention relates to a method for cleaning a building facade, as well as an installation for implementing this method.

By building is meant any construction such as a building or a historic monument for example.

The facades of buildings, for example of stone, are exposed in our polluted atmospheres to multiple physicochemical attacks which soil and weaken them.

Different methods have been developed for cleaning them.

These methods most often consist in spraying the facade with a powdery abrasive product (for example fine sand), pressurized water, or a mixture of these two constituents. These methods generally make it possible to obtain an effective cleaning but cause more or less significant abrasion of the stone or the coating. In fact it is more a question of wear on the surface than a real cleaning.

In addition, to carry out the cleaning operation, a manual method is most often used; an operator operates a cleaning device and moves it along the facade. The disadvantages associated with this method are numerous and of several types. First, it is a tedious and strenuous job; moreover, the operator is subjected to splashes of water or powdery materials, which requires the use of specially adapted clothing, for example a diving suit, and other protective accessories which impede the movements and visibility of the machine. operator, forcing him to work in unpleasant and tiring conditions, conditions which are further aggravated when the weather conditions are unfavorable.

Second, in order to make the cleaning operation profitable, it is necessary to work quickly. For this, one of the solutions applied consists in significantly increasing the spraying pressure of the cleaning product, which aggravates the aforementioned defect: the facade is subjected to wear rather than real cleaning.

Because of the work rates imposed on him, the operator can not perform careful work throughout a site, and the quality of work is not always perfect. Finally, the quality of the work is inevitably uneven, the various cleaning parameters such as the pressure of projection of the cleaning product, the distance of the cleaning device from the surface of the facade, the angle of attack of the jet of cleaning product, necessarily changing during work, especially since all these parameters are not the same depending on the type of stone or coating to be cleaned.

Finally, such cleaning methods cause the rejection of polluted powdery materials. In addition to the inconvenience for the operator, mentioned above, these materials evacuate themselves out of the cleaning area. It is then necessary to partition or cover the cleaning space in order to limit this evacuation and the inconvenience it causes (fall back into the street, etc.).

Described in US Patent No. 1,944,404 is a rotary cleaning apparatus which has two opposite arms at the end of which are arranged cleaning nozzles. The rotational movement of the device is caused by the reaction of the jet of cleaning product on the surface to be cleaned. Unfortunately, significant projection pressures are required to cause such rotation. However, as already mentioned above, significant projection pressures cause strong abrasion of the stone.

The present invention therefore aims to remedy the drawbacks described above. To do this, it offers a method as well as an installation which allows effective cleaning of building facades without significant abrasion, and by removing the cleaning area of the pulverulent materials released during this operation, as and when cleaning. The installation makes it possible to adjust the working parameters as best as possible (projection pressure, working speed, etc.) according to the nature and fouling of the surface to be cleaned. In addition, it makes it possible to obtain and guarantee a constant result throughout the work. It is a simple process to implement.

The cleaning process which is the subject of the invention is a mechanized process which consists in spraying on the facade, substantially perpendicular to the latter, at least one incident flow of a cleaning agent, according to a rotary movement which is combined with a second permanent back-and-forth movement along a path substantially parallel to the facade, and repeating these operations along the facade.

This process can be implemented by means of a robotic working head which is capable of working at a rate and at a rate which would be unsustainable manually, with the possibility of automatically adjusting the speed of rotation and back-and-forth movement. - comes from the head, which makes it possible to obtain a perfectly regular quality of work, adapted to the characteristics of the facade. By "incident flow" is meant the flow of the cleaning agent which strikes against the facade to be treated, this in opposition to the flow of particles which must be removed thereafter, which is composed of the cleaning agent responsible for impurities.

In a preferred embodiment of the method, the cleaning agent is sprayed inside a confined space which corresponds to the surface portion to be cleaned, and during the operation, the cleaning agent charged with impurities is sucked into this confined space, in an area which substantially surrounds the incident flow.

Preferably, the cleaning agent consists of a fluid consisting of pressurized air and a pulverulent cleaning product, for example alumina powder, glass powder or pumice powder.

The invention also relates to an installation for the automated implementation of this method. This installation is mainly characterized in that it comprises an enclosure which has an opening intended to be directed towards the facade to be cleaned and in that it contains, substantially in its central part, a working head ensuring the projection of a cleaning agent, the working head and the wall of the enclosure being separated by a peripheral space in which at least one suction means acts which is connected to a discharge duct on the side opposite to the opening.

According to other advantageous characteristics given without limitation:
the working head comprises a pipe for supplying the cleaning agent to one end of a fixed distribution tube, the second end of the tube opening out inside a rotary head adapted to receive at least one nozzle spraying the cleaning agent, said head being rotated about an axis which coincides with the longitudinal axis of the dispensing tube;
- The rotary head is integral with a tube in which the distribution tube is engaged, the rotational movement of the head being caused by the displacement of a gear wheel wedged on said tube, which meshes with the pinion of the 'output shaft of a drive motor;
- Said suction means consist on the one hand of a turbine mounted at the rear of the working head, and on the other hand, of fins mounted near the projection nozzles, the fins being moved in said annular zone , the rotational movement of these causing suction by vacuum cleaning agent laden with impurities and its evacuation to the conduit;
- the enclosure is extended, on the side of its opening by a brush seal;
- It is equipped with means for moving the working head inside the enclosure, according to back-and-forth movements;
- It is equipped with means for moving the enclosure vertically and horizontally, along the facade to be cleaned;
- Said means are programmed to sequentially move the enclosure horizontally at slow speed according to alternating round trips, and vertically, between each of these round trips, over a certain height which corresponds to the height of the previously cleaned area;
- It is equipped with means for moving the enclosure remotely and means for controlling the state of the facade to be cleaned and the cleaning carried out by the working head.

Thanks to such an arrangement, the speed of rotation of the projection nozzles combined with the reciprocating movement can be automatically corrected to take account of the proximity of the relief points of the facade, that is to say of the nearest or furthest points to be cleaned; for this, appropriate sensors carried by the enclosure are provided to detect this proximity before cleaning, so as to vary, depending on the distance measured, the speed of rotation of the nozzles as well as the speed of the second movement, c ' that is to say the movement back and forth. This correction is done in such a way that the closer the points of the facade which are detected are to the working head, the faster the speed of rotation and vice versa, this being also true for the reciprocating movement.

Other characteristics and advantages of the invention will appear from the description and the appended drawings which represent preferred embodiments thereof.

• - la figure 1 est une vue simplifiée en coupe longitu­dinale d'une enceinte formant une partie de l'installation de nettoyage ;
• - la figure 2 est une vue en coupe d'une tête de travail adaptable à l'enceinte de la figure 1 ;
• - la figure 3 est une vue simplifiée de l'installation de nettoyage, en place face à la façade d'un bâtiment ;
• - la figure 4 est une vue en pespective d'une partie de cette installation, en l'occurence le portique qui soutient l'enceinte de nettoyage.

In these drawings:

• - Figure 1 is a simplified view in longitudinal section of an enclosure forming part of the cleaning installation;
• - Figure 2 is a sectional view of a work head adaptable to the enclosure of Figure 1;
• - Figure 3 is a simplified view of the cleaning installation, in place facing the facade of a building;
• - Figure 4 is a perspective view of part of this installation, in this case the gantry which supports the cleaning enclosure.

Throughout the description and the appended claims, the term "cleaning without abrasion" means cleaning which makes it possible to rid a surface of the undesirable substances which adhere to it, without practically eroding it. These substances (dirt) most often consist of deposits of soot caused by releases into the atmosphere of industrial smoke, or dust and all other pollutants which have become attached and which have remained stuck to the surface of the facade.

The development of the method of the invention is part of the observation that if one cleans a facade by means of a rotary flow at high speed of a cleaning agent, the same surface will be scanned a number important times by the flow. Therefore, the spraying pressure of the cleaning material can be lowered significantly to make it non-abrasive. So this is the repeated passage of this agent on the surface which will gradually cause the removal of dirt by gentle and regular brushing. Gradually after each pass, a small part of the pollutants is removed, and it is after a certain amount of more or less important passages, in the same places, that the surface being cleaned will regain the desired color and clean appearance and this without visible abrasion. In addition, since the agent charged with impurities tends to evacuate towards a zone which surrounds the incident flow, it is particularly advantageous to simultaneously suck the agent charged with impurities in this zone.

Finally, the work is all the better done when a rotary movement of the flow is combined with a translational movement of automatic mechanical back-and-forth and adjustable speed of this flow parallel to the facade. Of course, on these combined movements of rotation and automatic back-and-forth, is superimposed another continuous and slower movement of movement of the flow along the facade. As we have just said, the mechanical projection makes it possible to iron tirelessly in the same places of a surface to be cleaned with absolute regularity, allowing a gentle and progressive cleaning, without any visible abrasion, result impossible to achieve manually. This mechanical spraying process allows the cleaning of dressed stone facades, obtaining a very good quality result.

By "high rotation speed" is meant, for example, a speed of the order of several tens to several hundred revolutions per minute.

The preferred cleaning agent is a fluid consisting of pressurized air which carries a powdery cleaning product. This is for example an alumina, glass or pumice powder and more generally a powder commonly used for cleaning metals. The particle size of these powders is for example of the order of 100 to 200 m.

The cleaning chamber shown in Figure 1 is an integral part of the installation for implementing the method of the invention.

The enclosure has a metallic outer wall 1 which, in cross section, may have a substantially oval shape. The long axis of the oval section is for example arranged horizontally. In addition, as seen in Figure 1, its section, constant in the vicinity of the opening 15, is reduced as one moves away from it to form a conduit 14 of reduced section. In its part of constant section, the wall 10 of the enclosure is split, so that it provides an annular space all around the wall 1. However, in order to stiffen this annular space, the latter is partitioned. There are thus formed recesses 10, only two of which are visible in FIG. 1, contain a compression spring 23, wedged between a plate 11 (fixed in the recess) and the plug 12. A longitudinal rod 21 passes through the plate 11 and the plug 12. It carries a washer 24 forming a stop intended to be pressed against the plug 12 under the action of the spring 23.

The rod 21, in its portion which opens out of the recess 10 passes through a bellows seal 23 consisting of a double envelope 230 formed of a material permeable to air and which contains a compressible and filtering filling product. The end of the rod 21 carries the support 20 of a generally annular brush 22, with an oval outline identical to that of the wall 1 of the enclosure. It is easily understood that if the enclosure moves in the direction of the facade F , there will be a backward movement of the rods 21 relative to the enclosure which will result in compression of each spring 23 in its recess 20 and crushing of the seal 23 in the direction of the arrow f . As soon as the enclosure has moved away from the facade, the springs will resume their original position, the stops 24 coming to rest against the plugs 12 and the seal its uncompressed form.

The enclosure contains in its central zone, materialized by the axis XX ′, a working head 4 carrying projection nozzles 5 for example two in number, as well as a suction turbine 3 with radial fins, mounted just at the rear of the head 4. These elements are made integral with the wall 1 of the enclosure by cross members not shown.

It is the head 4 which projects a cleaning agent against the facade F to be cleaned. An embodiment of this head will be described later in the description. A supply line 13 of a mixture of pressurized air and a pulverulent cleaning product opens out inside the head 4.

Note in FIG. 1 that the head 4 is separated from the wall 1 of the enclosure by a peripheral zone 16. The fins 30 of the turbine 3 are adapted to be moved in rotation in this zone by means of a non-motor represented. In the embodiment of FIG. 1, the projection nozzles 5 are integral with another series of fins 50.

In the embodiment of Figure 2, the working head has the form of a housing 40 of substantially parallelepipedal shape through which a cylindrical distribution tube 70 of which one of the ends 701 opens out therefrom. The other end 700 is tapped so as to receive the supply line 13 for the cleaning product. The distribution tube is housed in a second tube 71 of larger diameter; they are held coaxially apart from one another by a pair of ball bearings 42, 42 ′. Similarly, a pair of ball bearings 41, 41 ′ guides the tube 71 in rotation in the housing 40. On the tube 71 is wedged a gear wheel 73 which meshes with the pinion 61 of the drive shaft. outlet 60 of an electric motor 6. The end 710 of the tube 71 is secured to a head 72 which comprises two conduits 720, opening into the open air through tapped parts 721 adapted to receive the projection nozzles 5 (not shown) which have been mentioned above.

The head 72 has a central bore 722 adapted to receive by interlocking the free end 701 of the distribution tube 70. Appropriate seals are provided at this interlocking to ensure sealing between the fixed 70 and rotating 71 tubes.

The operation of the working head is as follows. The motor 6 is started while a circulation of cleaning product is carried out by means of an independent motor. The product arrives in the distribution tube 70, which it passes through, and arrives at the end 701 from where it passes through the conduits 720 of the head 72 subjected to a rotational movement around the axis X-X ′. It is then distributed through the nozzles 5.

The head 72 is for example fixed to the tube 71 by screws. We can therefore change the head 72 to replace it with another having ducts 720 of different shape, making it possible to use, as required, one or more nozzles, to use tilt, orientation and axis nozzles and use a variety of nozzles with different characteristics and different outlet diameters.

The automatic back and forth movements in translation, of more or less amplitude, of the head 4 inside the enclosure is possible thanks to the elongated shape, in this case oval, of the section of this enclosure. These movement movements are made over a small amplitude.

The lower part of the housing 40 is equipped with rollers 80, 80 ′ adapted to be moved along rails 8, 8 ′. These rails are integral with the wall 1 of the enclosure. The housing 40 is equipped with means making it possible to move it along the rails 8 according to reciprocating reciprocating movements. ticks and permanent. These means, not shown, consist for example of a double-acting pneumatic cylinder.

In addition to the enclosure which has been described previously, the installation of the invention includes other elements which make it possible to move it along a facade. An example of such an installation is shown in Figures 3 and 4.

For example: the installation 9, which equips the facade F of a building comprises a winch support 90 located at the level of the roof as well as a base 900 placed on the roadway which borders the building. Between these elements are stretched cables 91 and 93. These cables pass through tubes 940 placed at the four corners of a gantry 94 which supports a cleaning enclosure. A pair of cables 92, also connected to the gantry and the winch allows by means of a motor not shown to lower or raise the gantry as desired along the cables. Of course, the gantry is also equipped with means making it possible to block it in a desired position.

The enclosure is mounted on a system of sliding beams 95, 96 arranged perpendicular to the facade. Motor means, not shown, make it possible to slide the beam 96 relative to the beam 95 in the direction of the arrow v so as to be able to move the enclosure away from or closer to the facade at will. Finally, the enclosure moves laterally (in the direction of the arrow w - Figure 4 -) relative to the facade, the beam 95 moving relative to the gantry 94 along a raceway provided for this purpose.

The enclosure 1 is extended in its rear part by a pipe E for evacuating the cleaning agent charged with impurities, the lower end of the latter being equipped with a powerful suction device and of course, a container for storing the recovered product, this container being equipped with an air filter returning the filtered air to the outside.

In the vehicle V shown schematically in Figure 3 takes place an operator who has at his disposal the dashboard T of a computer and a set of video screens, allowing to control and command all the movements of the elements that make up the installation (speed of rotation of the nozzles, speed of the reciprocating movement of the working head inside the enclosure, etc.). Preferably, the cleaning enclosure is equipped with cameras (a C of which has been shown diagrammatically in FIG. 1) making it possible to control, by means of control screens located in vehicle V , the way in which the cleaning of the facade. It is also equipped with sensors and light sources not shown in the figures. The purpose of the sensors, of a type known per se, is to give an indication of the distance which separates the projection nozzles from the cleaning surface. It will be understood later on the advantage of such sensors.

The light sources have the function of allowing the installation to be used in poorly lit areas or for working at night.

We will now explain how the installation works. The operator begins by controlling the computer in such a way that the cleaning enclosure is placed, for example, the upper left part of the facade F of the building to be cleaned. The computer then controls the starting of the motor 6 of the working head 4, the circulation of a stream of cleaning agent up to it, and the movement of the enclosure at slow speed along of the facade in the direction of arrow w taking into account the characteristics of the surface to be cleaned (nature of the stone, surface condition, etc.). When the motor 6 is started, the implementation of the means making it possible to move the robotic working head 4 along the rails 8, 8 ′ in automatic reciprocating movements is coordinated. permanent. J rotating jets of cleaning agent are projected continuously against the facade. The projection pressure combined with the small particle size of the cleaning agent will allow incessant progressive rotary brushing of the facade without abrading it. This brushing will gradually remove the materials that soil the facade. These materials, as well as the soiled cleaning agent cannot come out of the enclosure because the seal 23 and the brush 22 seal the enclosure. Cleaning is therefore done at any time in a confined space corresponding to a specific area of the facade. The fins 50 which, in the embodiment of FIG. 1, equip the projection nozzles, will cause by their rotation a first suction effect which will convey the materials in the annular zone 16, surrounding the working head. At the rear of the latter, the fins 30 of the turbine 3 resume the flow of materials to orient it towards the evacuation pipe 14. The powerful suction device which is arranged at the lower end of the pipe E connected to line 14 evacuates the materials out of the enclosure.

If during the movement of the enclosure along the facade, one passes from a flat surface to an area forming a recess (balcony B , relief pattern D ) of significant thickness, the sensors mentioned above detect this change in surface, and the computer then orders the removal of the enclosure with respect to the frontage, in the direction of the arrow v (Figure 3). If these are relief elements having a small thickness (not requiring the removal of the enclosure), the computer will cause an acceleration of the rotation movement of the nozzles. Indeed, if the distance between the cleaning nozzles and a given surface varies, the jets of cleaning agent will be more or less abrasive. Consequently, if this distance decreases, this reduction in distance must be compensated for by a higher speed of rotation of the nozzles; in fact, the faster the rotation speed of the nozzles, the more the impact force of the particles on the support will be reduced and the less abrasion will be. At the same time, the speed of the back-and-forth movements of the working head can be increased inside the enclosure. Thus the function of the sensors is to cause the increase or decrease depending on the reliefs of the facade, first the speed of rotation of the projection nozzles, as well as the speed of the automatic back-and-forth. These two speeds having an independent adjustment.

When the enclosure has undergone a complete lateral displacement along the gantry 94, the computer then controls the descent, by regular automatic sequence, of the latter along the cables 91 and 93; once this operation has been carried out, a new cleaning is carried out by lateral displacement of the enclosure which departs in the opposite direction along the gantry of translation.

For purely indicative purposes, the installation may have the following characteristics:
- dimensions of the enclosure: height: approximately 1 m;
width: about 1.5 m;
depth: about 2 m;
- nozzle rotation speed: 10 to 500 revolutions / minute;
- translation speed of the working head inside the enclosure: 1 m / s;
- amplitude of the back-and-forth movement of the head in the enclosure: 0.4 m;
- cleaning capacity of an ordinary building facade: 5 to 25 m² / hour, this capacity of course depending on the various characteristics of the facade (type of coating, type of fouling, etc.).

Claims (12)

1. A method of mechanically cleaning a building facade, characterized in that it consists in projecting onto the facade, substantially perpendicular thereto, at least one incident flow of a cleaning agent, in a rotary movement which is combined with a second permanent back-and-forth movement along a path substantially parallel to the facade, and to repeat these operations along the facade. 2. A cleaning method according to claim 1, characterized in that the cleaning agent is sprayed inside a confined space which corresponds to the surface to be cleaned and that during the operation one sucks in this confined space the cleaning agent laden with impurities, in an area which substantially surrounds the incident flow. 3. A cleaning method according to one of claims 1 and 2, characterized in that the cleaning agent consists of a fluid consisting of pressurized air and a powdery cleaning product. 4. Installation for the automated implementation of the method according to one of claims 1 to 3, characterized in that it comprises an enclosure which has an opening (15) intended to be directed towards the facade to be cleaned and in that '' it contains, substantially in its central part, a working head (4) ensuring the projection of a cleaning agent, the working head (4) and the wall (1) of the enclosure being separated by a peripheral space (16) in which at least one suction means (30, 50) acts which is connected, on the side opposite to the opening (15), to a discharge duct (14) connected to a suction source. 5. Installation according to claim 4, characterized in that the working head comprises a supply pipe (13) of the cleaning agent at one end of a fixed dispensing tube (70), the second end of the tube opening into a rotating head (72) adapted to receive at least one projection nozzle (5) of the cleaning agent, said head being driven in a rotational movement about an axis (XX ′) which coincides with the longitudinal axis of the dispensing tube. 6. Installation according to claim 5, characterized in that the rotary head (72) is integral with a tube (71) in which is engaged the distribution tube, the rotational movement of the head being caused by the movement of a gear wheel (73) wedged on said tube (71), which meshes with the pinion (61) of the output shaft (60) of a drive motor (6). 7. Installation according to one of claims 4 to 6, characterized in that said suction means consist firstly of a turbine (3) mounted at the rear of the working head (4), and on the other hand, in fins (50) mounted near the projection nozzles (5), the fins (30, 50) being displaced in said annular zone (16), the rotational movement of these causing suction by depression of the cleaning agent charged with impurities and its evacuation towards the conduit (14). 8. Installation according to one of claims 4 to 7, characterized in that the enclosure extends, on the side of its opening (15) by a brush seal (2). 9. Installation according to one of claims 4 to 8, characterized in that it is equipped with means for moving the working head (4) inside the enclosure, according to back-and-forth movements. . 10. Installation according to one of claims 4 to 9, characterized in that it is equipped with means (9) for moving the enclosure vertically and horizontally, along the facade to be cleaned. 11. Installation according to claim 10, characterized in that said means are programmed to sequentially move the enclosure horizontally at slow speed according to alternating round trips, and vertically, between each of these round trips, over a certain height which corresponds to the height of the previously cleaned area. 12. Installation according to one of claims 5 to 11, characterized in that it is equipped with means for moving the enclosure remotely and means for controlling the state of the facade to be cleaned and the cleaning carried out by the working head (4).

Images