EP0017225A1 - Method and apparatus for cleaning surfaces or for keeping these clean - Google Patents

Abstract

Process and device for cleaning and keeping the cleanliness of surfaces (1) either vertical or sloped exposed to heavy fouling. At the upper edge of the surface to be cleaned a cleaning fluid of low volatility, and foam controlled, having cleaning properties is applied in a thin film by means of a nozzle, in particular a nozzle with fluidic oscillations (4) which does not have moving parts. This film flows continuously without interruption towards the bottom with a high turbulence forming waves (7) at short intervals, influencing significantly the cleaning of the surface. According to the invention one of the best cleaning fluids is constitued by 10% of surface active derivate, 45% of ethylglycol, 15% of polyethylglycol, 3% of dryer-polisher and 0.5% of a bactericide. A cleaning device for windows can be entirely integrated in the spaces (25, 29) of a metal or plastic window frame (20).

Description

The invention relates to a method and a device for cleaning or keeping clean at least one surface perpendicular or provided with a vertical component, in particular a light-reflecting, translucent or heat radiation-absorbing surface by applying a cleaning liquid to the upper surface edge by means of a nozzle device connected to a liquid pumping system and catches along the surface Area of liquid drained downwards in a collection container connected to the liquid pump system.

The areas can e.g. deal with road traffic signs, advertising surfaces, window panes, sun reflectors or similar surfaces which are exposed to increased pollution from dust particles in the air and whose value in use decreases with increasing pollution. Dirty, no longer clearly recognizable traffic signs represent a not inconsiderable danger for road users. Dirty advertising spaces lose their desired effect on a buyer. Dirty window panes, for example of high-rise buildings or commercial buildings, can often only be cleaned by skilled workers with great technical effort, and the already low efficiency drops sharply if the surfaces of solar generators are dirty.

With ever increasing environmental pollution, in particular with the constantly increasing pollution of the air, the pollution of surfaces has become an important problem, especially when it comes to large surfaces that are often not easily accessible and which have so far only required a considerable amount of personnel and material could be cleaned.

The object of the invention is to provide a method and a device for cleaning or maintaining such surfaces, which works continuously or only at regular intervals or at intervals or only on request or only when required and which is particularly suitable for large surfaces, like them among others can be found in solar generators or heliostats. However, the invention is also intended to be suitable for smaller areas such as e.g. can be found in traffic signs, which are often exposed to particularly heavy pollution.

In a preferred method according to the invention, the cleaning liquid consists of

• Fig. 1 eine nur teilweise dargestellte erfindungsgemäße Vorrichtung in Frontansicht und
• Fig. 2 eine erfindungsgemäße Vorrichtung für mehrere übereinander angeordnete Flächen, z.B. einer Fensterfasade eines Hochhauses und
• Fig. 3 und 4 Teilansichten einer weiteren erfindungsgemäßen Ausführung.

To carry out the method advantageously, the nozzle device consists of surface-active ethylene oxide adducts. Further advantageous embodiments and developments of the invention can be found in the features of the subclaims or the description below, in which exemplary embodiments are described with reference to a schematic drawing. Here shows

• Fig. 1 is a partially shown device according to the invention in front view and
• Fig. 2 shows a device according to the invention for several surfaces arranged one above the other, for example a window facade of a skyscraper and
• 3 and 4 are partial views of a further embodiment according to the invention.

In Fig. 1, a surface to be cleaned or kept clean is designated by 1. This can be a translucent glass or plastic pane, a light-reflecting pane with a metallic coating or a pane of a solar generator or heliostat that absorbs heat rays. In all cases there is an interest in keeping surface 1, which is constantly exposed to the environment, as clean as possible. The degree of pollution depends on the authenticity and the time that has passed since the last cleaning. If the degree of contamination is particularly high, there is an interest in keeping the dirt away from the surface 1, that is to say to prevent it from adhering to the surface 1. If the degree of soiling is low, it is sufficient if the surface is cleaned at certain intervals. Cleaning is usually not necessary during a rainy season. Cleaning may be necessary immediately after a rainy season.

According to the invention, two fluidic oscillators are located on or after the upper edge of surface 1 in the example, which are connected here to separate lines 3 for supplying cleaning liquid. This can e.g. are fluidic oscillators according to DE-OS 25 05 695, which emit a flat spray jet oscillating in one plane with a selected high frequency, a selected spray angle and a selected, essentially uniform droplet size, which forms a thin film of liquid on the upper edge of the surface , which extends without interruption essentially over the entire width of the surface 1 and coherently, without tearing down with a high, successive waves 7 generating turbulence down where the liquid is collected by a nozzle 6 and discharged laterally into a collecting container, not shown becomes. The liquid film can advantageously have a thickness of at least 80 m and at most 150 m. It can also be fluidic oscillators according to US Pat. No. 4,184,639 or international applications WO 79/00236.

The collecting container, from which the liquid is pressed into the lines 3 by a pump, can serve as the liquid source for the cleaning liquid. As soon as the area 1 of the stand dig running liquid film is cleaned, the pump, not shown, is switched off and only switched on again when the surface 1 is contaminated again. The degree of contamination can be measured using a photocell, via which the pump is automatically switched on and off. Depending on the type of cleaning liquid used, 1 residue of the cleaning liquid may remain on the surface after cleaning, which is disadvantageous. In such a case, it may be advantageous to exclude a rinsing liquid on the lines 3 after the cleaning has been completed. When the rinsing liquid is connected to the lines 3, the fluidic oscillators produce a rinsing liquid film on the surface 1, which rinses off the residues of the cleaning liquid. It is clear that the cleaning liquid can be connected to the lines 3 via a valve device, not shown, which switches off the cleaning liquid and simultaneously switches on the rinsing liquid. The control, not shown here, for switching the liquid sources on and off on the lines 3 can contain timers which determine the operating time of the liquid sources.

If surface 1 is to be protected from contamination, then a liquid, in the simplest case water, is selected which forms a protective film on surface 1, which is continuously maintained during the time to be protected.

In the event of strong solar radiation on the surface 1, the inflow quantity of the liquid into the lines 3 is increased in order to ensure that the liquid film on the surface 1 is not interrupted by evaporation. It is important in any case that the liquid film extends evenly over the entire surface 1 even in strong sunlight and runs down continuously without evaporating, which can only be ensured if the minimum film thickness of the liquid on the surface 1 is not below becomes. Depending on the width of the surface 1, a fluidic oscillator 4 may also be sufficient. For example, it is possible to spray the entire width of a windshield of a motor vehicle with a fluidic oscillator 4. On the other hand more than two fluidic oscillators 4 can also be arranged at certain distances from one another. The oscillators can also be connected to a common feed line 3.

2, a plurality of surfaces 1 are arranged one above the other. Corresponding surfaces 1 can be arranged one above the other in any number. This can be, for example, a window or glass front of a high-rise building or the outside surfaces of a solar generator.

In the example, the individual surfaces 1 are connected to separate cleaning devices. Each surface 1 has a liquid collection container 5, to the bottom of which a line 2 is connected, which is connected to a line 3 at the upper edge of a surface 1, from which one or more oscillator nozzles 4 branch off, which are not shown here. At the lower edge of each surface 1 there is a liquid collecting channel 6 which is connected to the collecting container 5 via a downward line 10. The liquid from the reservoir 5 is pumped into the line 3 via a pump, not shown. A filter 11 for the fine cleaning of the liquid is expediently connected upstream of the input of the pump. For the preliminary cleaning of the liquid, a further coarse filter 12 is present in the collecting container 5, via which the liquid returned from the collecting trough reaches the collecting chamber of the container 5. If the surfaces 1 are under the influence of rain, it must be prevented that rain water reaches the collecting container via the collecting troughs 6 because this can undesirably dilute the cleaning liquid. So this only applies to cleaning fluids that are not just water.

According to the invention, a valve slide or similar shut-off device 12 is provided for this at the outlet ends of the collecting troughs 6 or in the downcomers, with which the return path into the collecting container 5 can be interrupted. Instead of a shut-off device 12, the collecting trough can also be designed to be foldable about its longitudinal axis in such a way that it leaves the collecting area of the liquid at the lower edge of surface 1 can be pivoted away. The rainwater running downward on surface 1 then flows outward over the lower edge of surface 1 without reaching the collecting channel. Is the collecting trough fixed and. If a shut-off device 12 is provided, then the rainwater collecting in the collecting trough runs off to the outside via the collecting trough when the connection to the collecting container 5 is shut off.

It is clear that a multitude of solutions for the foldable collecting trough or for the shut-off device are available to the person skilled in the art, not all of which can be explained here. Furthermore, it is clear that in the case of an automatic cleaning device, the folding function of the collecting troughs or the shut-off functions of the shut-off devices 12 can be controlled by electrical or pressure-medium-operated control elements, which control signal, e.g. obtained from a hygrometer.

In Fig. 2, the individual surfaces 1 are connected to separate cleaning circuits. It is clear that instead of the individual collecting containers, a common collecting container can also be provided, to which the individual lines 3 to the individual distribution pipes are connected and to which the individual lines 10 are guided in connection with the collecting channels 6. The common collection container can then possibly make do with a single liquid pump.

The invention is not restricted to the exemplary embodiments on the basis of which the person skilled in the art can readily choose from a large number of parallel possible solutions for cleaning or keeping a surface with a liquid film running on the surface.

In particular, depending on the task within the scope of the invention, the person skilled in the art will be offered different liquids. It is clear that the liquid for cleaning or protecting against contamination of solar generators can differ from a cleaning liquid for windows. Common to all solutions, however, is the idea of a liquid in a coherent applying thin film to the surface to be cleaned or kept clean along its upper edge by means of a distributor device in such a way that liquid film runs down continuously over a large area of the entire width of the surface without tearing, with high, successive wave-creating turbulence.

These waves, which extend across the surface, follow one another at intervals and run downwards on the shaft, with their characteristic liquid turbulence, allow rapid, intensive surface cleaning that cannot be achieved by comparison with a laminar liquid film running downwards on surface 1. Fluidic oscillators in which the desired effects can be achieved with relatively low liquid pressures have proven particularly useful for producing the turbulent liquid film.

3 and 4 show yet another embodiment of the invention, namely for an automatic window cleaning. Figure 3 shows a vertical section through a window frame 20 in an opening 21 of a masonry 22. The compact window frame consists of a hollow profile made of aluminum or plastic, which carries two window panes 23, 24 between seals in a known manner. Above the upper horizontal edges of the disks, a nozzle connecting pipe 26 is held in a cavity 25 of the frame, on which short pipe sections 27 branch off at intervals, which can be connected via thread or plug connections to pipe sections 28, each of which has a fluidic oscillator nozzle 4 at its front ends wear with the nozzle 4 in Figure 1. The nozzle connection pipe 26 extends over the entire width of the window and has at least one of its two ends with a plug or thread connection for a riser pipe, not shown, which is held in a cavity of the window frame outside a vertical pane edge. The nozzle connecting tube 26 is held in a profile 29 on the outside of a cover 30 which is detachably attached to the upper horizontal section of the window frame, as the enlarged partial section in FIG. 4 shows. Removing the cover 30 gives access to the nozzle connection pipe 26 and the pipe sections 28 with the fluidic oscillator nozzles 4 which protrude through an opening 31 in the frame and are directed against the outer surface of the outer disk 23 at a selected angle. The nozzles 4 are largely protected from the outside by a frame cover 32.

In the lower vertical section of the window frame there is a larger cavity 29 which extends over the entire width of the window. The top surface of the cavity 29 forms an inner window sill, which has a lid 30, through which there is access to the cavity 29, which serves as a collecting container for the cleaning liquid. A profile gap 32 in the frame profile below the lower window edges adjoins the upper end of the cavity 29 via a run-off bevel surface, which is connected to an outwardly open entry slot 33 of the frame profile, which is located near the lower horizontal edge of the outer window pane 23. The entry slot 33, which extends over the entire width of the window panes 23, 24, is covered by an outer slit diaphragm 34, which is directed obliquely from the outside against the outside of the outer window pane 23. This slit diaphragm 34 leaves between its front end and the outside of the window pane 23 a narrow gap 35, which extends over the entire width of the window, through which the cleaning liquid running down the pane 23 enters the inlet slot 33 and the profile gap 32, where it is guided into the cavity 29 along the run-off inclined surface 31. A filter 36 is held in the cavity 29 on wall jumps 37 in the cavity 29, which can be replaced via the cover 30 and via which the liquid enters the cavity. The above-mentioned riser, the upper end of which is detachably connected to one end of the nozzle connecting pipe 26, is connected at its lower end to the outlet of an electric pump, which is not shown here and whose suction nozzle is held at the lowest point of the collecting cavity 29 .

It is readily apparent to the person skilled in the art that a compact window frame, which in the horizontal upper section includes a nozzle connection pipe with one or more oscillating nozzles projecting outwards and in the horizontal lower section a collecting container with access to the outside, and that at least in one side frame section a riser pipe between one Pump in the reservoir and the nozzle connecting pipe receives, can be designed in many different ways, depending on whether the window frame is made of plastic or aluminum and in which way the frame is made. What is essential here is the knowledge put forward by the invention that a cleaning device according to the invention can be integrated in a window frame without the frame having to be substantially wider than the conventional frame. The window frames can be designed as compact finished parts. Here there are simple options for connecting the individual liquid containers of several window frames in one set via line sections which can be laid in the masonry between wall openings for inserting the window frames, so that several windows can be connected to a central pump system. By accommodating a cleaning device for windows according to the invention in a window frame, there is a surprisingly simple construction also for replacing the nozzle connecting pipe 26 with the oscillator nozzle or nozzles via an inside cover. The entire maintenance of the device, including the liquid, is advantageously possible from inside the building.

The problem with specifying the cleaning liquid according to the invention was that the liquid must remain essentially unchanged over a long period of time.

In the purification of any of the dirt out _- put surfaces such. B. street signs of all kinds, glass surfaces, advertising surfaces, particularly heavy dirt exposed wall surfaces of public buildings, for. B. also tunnel walls of car underpasses, or to protect monuments from industrial and motor vehicle exhaust gases, the period during which the liquid must be available essentially unchanged and ready for operation can be considerably longer than half a year. In the latter case, the liquid according to the invention not only has a cleaning function, but also a protective function Corrosion from aggressive gases.

In many cases it is advantageous if the cleaning liquid is highly viscous and low-evaporation, has low-foam properties, a low freezing point and a pronounced wetting, washing, dispersing and homogenizing ability, so that a thin, closed surface on an object , can be formed with a low flow rate flowing down liquid film, which is particularly suitable for cleaning solid surfaces of all kinds.

For a largely simple formulation of the cleaning liquid, it is essential that the liquid is composed of as few constituents as possible, each constituent combining as large a number of functions as possible.

So there are liquid detergents as detergent agents, which not only have good washing and wetting effects, but which are also low-foam or foam-suppressed. Furthermore, detergent agents with good emulsifying and dispersing properties are known. Such means can be technical products or product mixtures. Since the glycol used as an antifreeze, provided it makes up at least 40% by weight of the cleaning liquid, has a strong foam-inhibiting effect, an additional emulsifier and an additional antifoam can be dispensed with if the water-soluble surfactants are selected appropriately.

auf. Als Glanztrockner kann z. B. Isopropylalkohol bzw. Isopropanol verwendet werden, wobei in einem Beispielsfalle mit 3 Gew.-% gute Ergebnisse erzielt wurden. Die Glanztrockner verhindern das Zurückbleiben von feinsten Restfilmen auf der Fensterfläche, die die Fenstergläser trüben. Als Frostschutzmittel kommen technische Äthylenglykole in Frage. Hierbei ist es vorteilhaft, wenn das technische Äthylenglykol noch von der Herstellung her Di-, Tri- und Polyäthylenglykole enthält. Weiterhin kann auch konfektioniertes Gefrierschutzglykole eingesetzt werden, wie es z. B. unter dem Warenzeichen Glygen auf dem Markt ist.It is also possible under certain conditions to do without a special evaporation inhibitor. By a certain increase in the concentration of the glycol used as an antifreeze to at least 40% by weight of the Cleaning liquid will significantly reduce water evaporation. If, in addition, a product is used as a viscosity-increasing agent which additionally reduces the rate of evaporation of water, the evaporation inhibitor can also be omitted. The cleaning liquid according to the invention then consists essentially of z. B. only from water-soluble surfactants, glycols and polyglycols and optionally a gloss dryer. In order to obtain a sufficiently long service life for the aqueous liquid without substantial changes in its properties, it may be essential that a small amount of a bactericide must be added. Thereafter, the liquid according to the invention

on. As a gloss dryer z. B. isopropyl alcohol or isopropanol can be used, good results being achieved in an example case with 3 wt .-%. The gloss dryers prevent the finest residual films from remaining on the window surface, which cloud the window glasses. Technical ethylene glycols can be used as anti-freeze. It is advantageous if the technical grade ethylene glycol still contains di-, tri- and polyethylene glycols from the production. Ready-made antifreeze glycols can also be used, as described for. B. is on the market under the trademark Glygen.

Technical propylene glycol can also be used as an anti-freeze. As with technical ethylene glycol, it is also advantageous with technical propylene glycol if it still contains the secondary products formed in the synthesis of propylene glycol from propylene oxide and water, such as di-, tri- and polypropylene.

It is expedient to work both with the use of technical ethylene glycol and technical propylene glycol or in a mixture of both with a glycol content of 45 to 55% by weight in the cleaning liquid. At this glycol concentration, the ice flocculation point is -35 ° C or lower. In addition, the water evaporation rate is very slow at this glycol concentration and surfactants show only a low level of foaming in such a water-glycol solution. Surprisingly, it was found that with such a high glycol content in the cleaning liquid, the washing, wetting, dispersing and emulsifying effects of certain surfactants are not impaired. This applies above all to non-ionic surfactants such as polyethers, especially alkylphenol polyglycol ethers.

Possible viscosity-increasing agents are high molecular weight (molecular weight from 1000 to 2000) polyglycols, high molecular weight polyarylates or high-boiling glycol ethers or glycol esters.

The selection of the viscosity-increasing agents is based on the criteria that, on the one hand, the viscosity of the water-glycol solution is increased and, on the other hand, the viscosity differences in colder and warmer seasons are largely compensated for. This means that the viscosities of the cleaning liquid must not be too high at temperatures of -20 ° C and not too low at + 40 ° C, so that in one case the cleaning liquid still flows sufficiently quickly and in the other case it does not flow too quickly.

In this context, good results also show water-soluble cellulose ethers to which a hydroquinone adduct has been added as a stabilizer.

At 8 to 12% by weight (preferably around 10% by weight) of water-soluble surfactants (ethylene oxide adduct), 45 to 65% by weight (preferably around 55% by weight) technical ethylene glycols and / or technical propylene glycols, 0 , 2 to 1.5% by weight (preferably around 0.75% by weight) of water-soluble cellulose ethers with 0 to 0.5 hydroquinone adduct, satisfactory results have been achieved as a cleaning liquid.

As mentioned, suitable surfactants are, as mentioned, those surfactants which are soluble in a 40 to 70% by weight glycol solution and the wetting, washing, dispersing and emulsifying action are retained to a sufficient extent. In addition, the cleaning liquid must be low in foam.

In a mixture of 45 to 55% by weight (preferably 45% by weight) of ethylene glycol and 5 to 10% by weight (preferably around 10% by weight) of polyethylene glycol and the rest of water have been found to be detergent agents with pronounced wetting agents. , Washing, dispersing and emulsifying effects of non-ionic surfactants, in particular alkyl ethers, in amounts of 5 to 10% by weight (preferably around 10% by weight) have been proven. These include in particular the water-soluble alkylphenol polyglycol ethers (nonylphenol ethoxylates) available on the market under the trademark Marlophen 88 and 89.

Under suitable conditions, surfactant ethylene oxide adducts have also proven useful as detergent agents, namely in amounts of 8 to 12% by weight (preferably around 10% by weight) in 40 to 50% by weight (preferably around 45% by weight). %) technical ethylene glycols and / or technical propylene glycols and 0 to 20% by weight (preferably 10 to 20% by weight, especially around 15% by weight) technical polyethylene glycols and / or technical polypropylene glycols, the rest being water.

Because of the relatively high water content of the cleaning liquid, it has been found that 0 to 1% by weight (preferably around 1% by weight) of bactericides must be added so that the liquid does not prematurely with the long service life provided degraded by microbacteria and thus one or more of their effects is impaired. For example, formaldehyde or chloracedamide are suitable as bactericides. Depending on the substance used, 0.2 to 0.5% by weight may also be sufficient. The bactericides should be selected so that they have practically no influence on the various effects of the cleaning liquid.

The shown examples of liquids according to the invention are used primarily for cleaning purposes, it being assumed that the cleaning liquid should be effective in colder seasons with frost and in warm seasons with strong sunlight. It is readily apparent to the person skilled in the art that the formulation of the cleaning liquids has to be adapted to the local conditions, in particular when antifreeze is not required. The formulation of the cleaning liquid will also depend on whether it is mainly used for cleaning surfaces against dust and whirled up, fine-grained dirt or for protection against aggressive gases. The invention also includes the use of liquids for protective purposes or for cleaning and protective purposes.

Claims (16)

1. A method for cleaning or keeping at least a vertical or provided with perpendicular component surface, particularly light-reflective light-transmissive or heat radiation receiving surface by applying a cleaning liquid on the upper surface of the edge by means of a load connected to a fluid pumping system nozzle apparatus and collector along the surface by un _- th expired liquid in a collecting container connected to the liquid pumping system, characterized in that the low-evaporation, foam-inhibited, washing-active properties cleaning liquid is applied to the upper surface edge in a thin closed film, which without interruptions as a coherent essentially extending over the entire width of the surface Liquid film with a high, successive wave-generating turbulence runs down. 2. The method according to claim 1, characterized in that the liquid

3. The method according to claim 2, characterized in that polyglycols are replaced by high molecular weight polyarylates or high-boiling glycol ethers or glycol esters. 4. The method according to claim 2, characterized in that the liquid

5. The method according to claim 4, characterized in that the non-ionic, water-soluble surfactants are alkyl ethers. 6. The method according to claim 2, characterized in that the liquid

7. The method according to claim 2, characterized in that the liquid

8. The method according to claim 6 or 7, characterized in that the water-soluble surfactants consist of surfactant ethylene oxide adducts. 9. The method according to claim 1, characterized in that the nozzle device is connected after a cleaning operation of a selectable period of time to a rinsing liquid source for rinsing off cleaning liquid residues on the cleaned surface. 10. The method according to claim 1 or 9, characterized gekennzecinet that the cleaning is carried out regularly (preferably at night). 11. The method according to claim 1 or 9, characterized in that the cleaning is carried out as a function of the degree of contamination of the surface to be cleaned for a selectable period of time, wherein the degree of contamination is measured by a photo source. 12. The method according to claim 1, characterized in that the amount of liquid to be dispensed to the nozzle device is controlled in order to achieve a coherent liquid film that runs downward on the surface and is selectable as a function of the outside temperature. 13. The method according to claim 1, characterized in that the liquid pumping system is controlled in dependence on the external air humidity. 14. The method according to claim 1 and 13, characterized in that when rainwater strikes against the surface of the collecting container for the cleaning liquid is switched off from the inflow of rainwater. 15. A device for performing the method according to claim 1, characterized in that the nozzle device consists of at least one fluidic oscillator nozzle without moving parts for dispensing a back and forth in a plane oscillating flat spray jet with a selectable frequency, spray angle and droplet size. 16. The apparatus according to claim 15, characterized in that the device is integrated in a metal or plastic window frame having a horizontal upper frame portion with an elongate cavity extending substantially over the entire width of the window for receiving a nozzle manifold, of which at least a connecting pipe accessible from a frame inner cover branches out, which is led through a frame opening above the window glass to the outside, that a fluidic nozzle (oscillator nozzle) is held at the free end of the connecting pipe, which is outside the frame at a selected angle against the upper edge of the is directed outer window glass that the connecting pipe is releasably connected at least at one end to a riser pipe which is held in a vertical cavity of one of the two time frame sections, that a cavity in the horizontal lower frame section is designed as a liquid collecting container ld is which is connected to a slot through the frame section below the lower edge of the window glass, which extends essentially over the entire width of the window and through which the cleaning liquid which has run off the outside of the window glass reaches the collecting container, which is accessible from inside the building, that at the deepest point of the container an intake port of a feed pump is held, the outlet opening of which is connected to the lower end of the riser pipe.

Images