EP3075902B1 - Cleaning apparatus - Google Patents

Description

The invention relates to a device and a method for cleaning a surface, preferably a conveyor belt of a drying screen of a paper production plant.

As paper production plants run faster and faster, more powerful cleaning devices are required for dry screen cleaning. These should be free of breakdowns, provide very good cleaning performance, conserve resources (water, energy, conveyor belt material), not only remove dirt particles from the belt but also transport them away in a controlled manner and dry the dry screen as quickly as possible after cleaning.

In practice, various solutions are offered for this.

The DE 295 17 859 U1 describes a cleaning system that cleans a conveyor belt using air or liquid jets generated by fixed nozzles, whereby dirt and/or water mist or residual water can be sucked in and removed by a cleaning head (referred to there as a "suction cup") using a negative pressure generated in it. The jet nozzles are installed either inside or below the suction chamber.

The DE 693 14 805 T2 describes a cleaning device that generates a liquid jet for cleaning the surface via at least one nozzle located in a cleaning head (referred to therein as a "suction nozzle") and applies it to the surface. In addition to the negative pressure generated in the cleaning head, compressed air is supplied to the main opening of the cleaning head so that it impacts on the treatment liquid deflected from the surface and material released from the surface and pushes them into Direction of the cleaning head interacting with the suction effect of the cleaning head.

A disadvantage of the prior art solutions is that the nozzles, if they are arranged inside the cleaning head, run the risk of becoming clogged by the dirt that is sucked in and removed from the surface being cleaned. There is also the risk that the cleaning head will become clogged by the detached and sucked-in dirt residues, especially if the cleaning head contains the angular nozzles or even just parts of the nozzles. If the nozzles are installed outside the cleaning head, the distance between the cleaning head opening and the surface to be cleaned had to be increased so that the jets hit the surface to be cleaned. The increased generation of splash water and dirt had to be either accepted or compensated for by using more suction energy.

Further cleaning devices are available from the WO94/12349 A1 and the EN 10 2007 028341 A1 known.

The object of the present invention was to provide a device and a method for cleaning a surface, in particular a conveyor belt of a drying screen of a paper production plant, which avoid the disadvantages of the prior art.

The object is achieved by a cleaning device or a method according to the independent claims. Advantageous further developments are defined in the subclaims.

In an advantageous embodiment, the object is achieved by a cleaning device (20) for cleaning the conveyor belt (1) of a drying screen in a paper production plant (2) comprising at least one cleaning nozzle (40) for generating a high-pressure jet (60) a liquid with an impact point (61) on the treadmill, at least one cleaning head (80) with a discharge opening (84) and a main opening (81) facing the treadmill (1), wherein the cleaning nozzle (40) is arranged outside the cleaning head (80).

The conveyor belt is preferably the conveyor belt of a drying screen or the drying screen itself and is usually made of a porous, air-permeable material in which dirt and paper residues easily accumulate. However, the cleaning device according to the invention is also suitable for analogous applications in which a surface, preferably in motion, is to be cleaned.

A cleaning nozzle or jet nozzle according to the invention is a nozzle that is designed to generate a jet of a fluid, preferably a jet of a liquid. It is preferably at least one diamond nozzle. The cleaning nozzle is preferably designed to generate a high-pressure jet. This pressure is preferably in the range of 250 to 600 bar, particularly preferably in the range of 350 to 560 bar. The pressure is most preferably 450 bar. This liquid is preferably water. The diameter of the nozzle opening is preferably in the range of 0.1 mm to 0.3 mm. The diameter is particularly preferably approximately 0.15 mm. The cleaning nozzle preferably has a connecting hose that is designed to supply the fluid used. A high-performance pump is preferably connected to the other end of the connecting hose. The supply hose is particularly preferably a Teflon hose. The jet direction - and thus also the point at which a jet generated by the cleaning nozzle hits the treadmill (the impact point) - is adjustable. Preferably, the jet direction can be adjusted via the cleaning nozzle holder.

The alignment of a cleaning nozzle according to the invention can preferably be adjusted via two angles. Firstly, this is the angle W1 which the imaginary projection of a high-pressure jet generated by the cleaning nozzle encloses with the running direction of the conveyor belt (see 63 in Figure 7 ). On the other hand, this is the angle W2 that the high-pressure jet generated by the cleaning nozzle forms with the surface of the conveyor belt (see 64 in Figure 7 ). Preferably, the orientation of a cleaning nozzle according to the invention can be varied electromechanically and/or hydraulically during the cleaning process.

The cleaning head is a component that is already known in a similar way from the state of the art. In DE 295 17 859 U1 and DE 693 14 805 T2 cleaning heads are described that serve as suction bells or suction chambers. The cleaning head in this invention is not limited to operation as a suction chamber, as in the prior art. The components described below also provide for operation of the cleaning head in which dirt and splash water is removed by excess pressure in the interior of the cleaning head. The cleaning head preferably has a round cross-section and encloses an interior in which substances such as the splash water and/or dirty air and/or suspended matter that is produced during cleaning and carries dirt with it can be collected. Furthermore, the cleaning head preferably has a discharge opening through which the collected substances can be removed from the interior of the cleaning head or can escape. The cleaning head is preferably a tube-like component. A particularly preferred arrangement is that the center axis of the cleaning head is located 3-8 mm in front of the tangential line of the dryer fabric return roll or any of the dryer fabric rolls of the moving conveyor belt. The cleaning head is preferably arranged perpendicular to the surface of the conveyor belt. The cleaning head preferably points to the The discharge opening - in the case of a pipe, for example, at the end of the pipe facing away from the conveyor belt - has a connector to which the cleaning head can preferably be connected to a drainage and/or vacuum system. The connector is preferably a quick-release system. A quick-release system allows the cleaning head to be quickly connected or disconnected and replaced. If it needs repair or thorough cleaning, it can be disconnected in a time-saving manner. This avoids long downtimes of the cleaning device and thus of the paper production plant. The cleaning head is preferably telescopic and can be put together from several pipe segments.

The opening of the cleaning head facing the conveyor belt is the main opening. The diameter of the cleaning head preferably increases towards the main opening. The diameter of the main opening is preferably in the range from 50 mm to 400 mm, particularly preferably the diameter is approximately 230 mm. The interior space between the main opening and the discharge opening preferably defines a discharge path for the collected substances. The cleaning head preferably has kinks and/or bends between the main opening and the discharge opening, so that the discharge opening is preferably located to the side of the conveyor belt. The cleaning head preferably has a sealing device at the cleaning head opening. This sealing device is preferably a rubber lip adapted to the opening geometry. The cleaning head preferably has closable openings or inspection openings in its outer surface. These closable openings are preferably arranged in the area of the cleaning head end facing away from the conveyor belt - e.g. in the area of the pipe end facing away from the conveyor belt - particularly preferably in the area of kinks and/or bends in the cleaning head. The closable openings are preferably designed in such a way that the interior of the cleaning head can be cleaned from the outside. The advantage is that in the event of a moderate blockage, the cleaning head easy to clean from the outside, for example by jet washing.

In an advantageous embodiment, the device according to the invention has at least one cleaning nozzle which is mounted outside the cleaning head. This cleaning nozzle is preferably located outside an air flow in the interior of the cleaning head which, during operation, carries a mixture of dirt and water. The cleaning nozzle is thus protected from contamination by dirt and water in the air flow. A cleaning nozzle is particularly preferably arranged outside the cleaning head and outside the imaginary extension of the cleaning head between the main opening and the treadmill. A cleaning nozzle mounted outside the cleaning head is preferably at a greater distance from the treadmill than the main opening. The cleaning head is preferably adjustable in rotation relative to at least one of these existing cleaning nozzles, particularly preferably in translation. The distance and/or orientation of at least one cleaning nozzle relative to the cleaning head is preferably changeable. Preferably, at least one cleaning nozzle mounted outside the cleaning head has a minimum distance from the outer surface of the cleaning head greater than zero, preferably in the range of 0.1 mm to 500 mm, particularly preferably 1 mm to 250 mm, very particularly preferably 2 mm to 90 mm, further very particularly preferably 3 mm to 80 mm, further very particularly preferably 5 mm to 70 mm and further very particularly preferably 10 mm to 60 mm. Particularly preferably, the nozzle opening has this aforementioned minimum distance from the outer surface of the cleaning head. Preferably, the cleaning nozzle is arranged in such a way that a fluid jet generated by the cleaning nozzle bridges a preferably free path outside the cleaning head before it reaches the interior of the cleaning head. Preferably, the cleaning nozzle is not in direct contact with the cleaning head. Preferably, The cleaning nozzle is preferably connected to the cleaning head solely via a holder which preferably protrudes from the outer wall of the cleaning head.

Due to the described arrangement of the cleaning nozzle - including the nozzle retaining nut - outside the cleaning head, it is not exposed to the air flow inside the cleaning head. Due to the arrangement of the cleaning nozzle and especially the nozzle opening outside the cleaning head and not inside, the path of this air flow is not blocked. Maintenance access to the existing cleaning nozzles is free. The nozzles also do not become clogged by suspended particles or dirt in the air, which is particularly carried by the air flow inside the cleaning head. In addition, this allows a cleaning head to be used in a simple design, without internal brackets, recesses or screw-on bushings or similar for cleaning nozzles where dirt collects. This also makes the cleaning head easier to clean.

The cleaning head and the cleaning nozzles present - and in the case of further embodiments described later, also the other components described - can also be used in other cleaning devices. The cleaning head, together with the components attached to it, is preferably spaced 5 mm to 20 mm from the conveyor belt during cleaning operation. This distance is particularly preferably approximately 10 mm.

In a further embodiment of the present invention, the wall of the cleaning head (80) has at least one inlet opening (82) and at least one cleaning nozzle is aligned such that a high-pressure jet (60) from the cleaning nozzle (40) is directed from the outside through one of the existing inlet openings (82) onto the treadmill (1).

An inlet opening is, for example, a small hole, a bore, an oblique bore, a gap that preferably runs parallel to the cleaning head axis that is perpendicular to the conveyor belt plane (for example: the pipe center axis if the cleaning head is preferably a pipe-like component), a recess or other passage that has at least the diameter of the high-pressure jet. The diameter of such an inlet opening is in the range of preferably 0.1 mm to 200 mm, particularly preferably 0.125 mm to 100 mm, very particularly preferably 0.15 to 10 mm, furthermore very particularly preferably 0.15 mm to 3 mm. At least one such inlet opening is located in the wall of the cleaning head. A high-pressure jet can be passed through such an inlet opening from the outside into the interior of the cleaning head. The point of impact of the cleaning nozzle arranged outside the cleaning head can thus be set to a point on the conveyor belt that lies within the outline of the projection of the geometry of the main opening onto the conveyor belt. Such a point would be covered without the inlet opening through the side wall of the cleaning head if the cleaning head was attached with the main opening in the immediate vicinity of the treadmill. An inlet opening can also be covered with adhesive tape, for example, so that a cleaning jet then shoots a hole through the adhesive tape and the inlet opening has a diameter that is precisely adapted to the diameter of the cleaning jet.

The inlet opening allows at least one jet to hit the treadmill at a point preferably in the air flow of the cleaning head, preferably within the inner contour of the main opening of the cleaning head projected onto the treadmill, despite the cleaning head being mounted close to the treadmill Dirt and waste water can thus be collected directly at the point of origin and preferably transported away without there being a large gap between the main opening and the conveyor belt, through which dirt can escape and the power used to generate an air flow in the cleaning head would no longer be concentrated on the point where the dirt and suspended matter (or similar) originated. At the same time, the cleaning nozzles mounted outside the cleaning head are in a position protected from contamination. In addition, this arrangement enables smaller diameters of the cleaning head and the main opening and thus a much simpler design and a greater effect of an air flow in the cleaning head on the area of the impact points of existing cleaning jets. Energy savings are the positive result. Another advantage is that the impact points of the high-pressure jets - depending on the size of the inlet openings in the cleaning head - are still easily adjustable or adjustable. Even cleaning with a swirl jet from outside the cleaning head is possible. The entire system can be flexibly adapted to different requirements.

In a further embodiment of the present invention, when more than one cleaning nozzle (40) is present, the cleaning nozzles (40) are distributed around the cleaning head (80) and aligned such that the high-pressure jets (60) generated by the cleaning nozzles (40) strike an area of the treadmill (1) which lies within the imaginary projection of the outline of the main opening (81) onto the treadmill (1).

Preferably, the cleaning nozzles are distributed at equal distances from one another around the cleaning head. Particularly preferably, the cleaning nozzles are distributed around more than half the circumference of the cleaning head. Particularly preferably three cleaning nozzles are arranged. The number of cleaning nozzles present is preferably equal to the number of inlet openings present. The cleaning nozzles are preferably aligned such that only one cleaning nozzle is assigned to each inlet opening. The cleaning nozzles are advantageously aligned such that the high-pressure jets generated impinge on the treadmill from different directions, preferably on a line parallel to the running direction of the treadmill. The cleaning nozzles are advantageously aligned on a small, preferably elliptical area on the treadmill in the range of preferably 1 mm ² to 8 mm ² , particularly preferably 2 mm ² and 4 mm ² , preferably in the region of the central axis of the main opening.

This means that only a small area is wetted by the liquid and the jet energy is applied in a concentrated manner. Preferably, all impact points of the high-pressure jets are within a circular area with a radius of preferably 5 cm, particularly preferably 16 mm, and most particularly preferably 5 mm.

Preferably, the cleaning nozzles are aligned at points which are spaced apart from one another by not more than 1 cm, preferably not more than 5 mm, particularly preferably not more than 3 mm, most particularly preferably not more than 2 mm.

By irradiating only a small area of the treadmill, only a small area of the treadmill is wetted with liquid and the jet energy is concentrated on a small area. This increases the cleaning power and at the same time subsequent independent drying or drying via a drying device can be carried out more effectively because only a small area needs to be dried. Effective drying is very beneficial for a drying screen because a drying screen that is not thoroughly and evenly dried will cause water streaks in the newly produced paper web and the paper thus loses quality.

When using three cleaning nozzles, the cleaning nozzles are preferably aligned as follows (see Figure 7 ), that the first two cleaning nozzles preferably face each other transversely to the running direction of the treadmill and are preferably aligned at two points, the imaginary connecting line of which is preferably parallel to the running direction of the treadmill and has a length in the range of preferably 0.5 mm to 3 mm, particularly preferably 1 mm to 2 mm. For the nozzles, an angle W1 is set in the range of preferably x ± 45°, particularly preferably x ± 15°, very particularly preferably x ± 5°, where x = 90° applies to one nozzle and x = 270° for the opposite nozzle. The third cleaning nozzle is aligned at a third point. Preferably, the third point is preferably located in the running direction of the treadmill, preferably after the impact point of the first two cleaning nozzles, at a distance of preferably 0.5 mm to 3 mm, particularly preferably 1 mm to 2 mm. Preferably, W1 for the orientation of the third nozzle is 180 ± 5°, particularly preferably 180 ± 2 15°, very particularly preferably 180 ± 0.1°. W2 for each of the existing cleaning nozzles is in the range of preferably 5° and 85°, particularly preferably 10° and 60°, very particularly preferably 15° and 45°.

In a further embodiment of the present invention, the cleaning nozzles (40) are aligned such that the high-pressure jets (60) have a common impact point (61) on the conveyor belt (1).

Preferably, the high-pressure jets are directed approximately towards a common point of impact.

In a further embodiment of the present invention, at least one of the existing cleaning nozzles (40) arranged to generate a laminar high-pressure jet (60).

In a further embodiment of the present invention, the cleaning device (20) has a tempering unit (70) for controlling the temperature of the high-pressure jets (70).

The temperature control unit is preferably arranged in the area of the high-performance pump. The temperature control unit preferably has a continuous flow heater for controlling the temperature of the high-pressure jets.

In a further embodiment of the present invention, the temperature control unit (70) has a heat exchanger (71).

According to the invention, at least one device (100) for supplying compressed air (101) is arranged in the region of at least one impact point (61) of at least one high-pressure jet (60) on the treadmill.

The device for supplying compressed air is preferably a preferably ring-shaped hollow body (torus or "doughnut"), which preferably has a connection for a compressed air hose, particularly preferably a channel for supplying compressed air from a compressed air pump or compressed air source to the hollow body. The device for supplying compressed air is preferably arranged at a distance of between 25 mm and 250 mm, particularly preferably between 100 mm and 130 mm from at least one impact point. It is preferably arranged on the same side of the treadmill on which the cleaning nozzle is arranged. The shape of the hollow body is preferably adapted to the shape of the main opening of the cleaning head. The device for supplying compressed air is: preferably arranged on the main opening; preferably attached to the main opening without a gap; Preferably implemented with the cleaning head in a structural unit.

In a further embodiment of the present invention, the device (100) for supplying compressed air (101) has at least one air supply opening (102), wherein the existing air supply openings (102) are arranged such that the supplied compressed air (101) forms an air curtain (103) which deflects the liquid bouncing off the treadmill (1) in the direction of the main opening (81).

Air supply openings are preferably small holes and/or gaps. They preferably have a diameter in the range of preferably 0.1 mm to 1.5 mm, particularly preferably 0.3 mm to 1 mm and very particularly preferably between 0.35 mm and 0.8 mm, particularly preferably a diameter of approximately 0.4 mm. In a preferred embodiment of the device for supplying compressed air as a preferably annular cavity, compressed air can be supplied via the existing connection into the cavity and then out of the cavity through the air supply openings. The air supply openings are preferably arranged and aligned in such a way that the gap between the device for supplying compressed air and the treadmill can be shielded by compressed air.

In a further embodiment of the present invention, the device (100) for supplying compressed air (101) is arranged such that air supply openings (102) are distributed around the edge of the main opening (81), which are essentially aligned with a point within an imaginary extension of the cleaning head (80).

Preferably, a hollow body is provided which is adapted to the shape of the main opening and is preferably arranged at the edge of the main opening, with air supply openings The hollow body is preferably arranged at the main opening outside the cleaning head. The hollow body preferably surrounds the cleaning head. The air supply openings are preferably arranged such that they form an angle of between 15° and 45°, particularly preferably an angle of approximately 30°, with the plane of the conveyor belt. They are aligned such that the individual compressed air jets converge towards the central axis of the cleaning head. Preferably, 6 to 30, particularly preferably approximately 12 air supply openings are arranged preferably at equal distances from one another in the device for supplying compressed air.

In a further embodiment of the present invention, a device (120) for supplying at least one water jet (121) is provided within the cleaning head (80), wherein the water jets (121) generated are directed substantially in a direction towards the discharge opening (84).

The device for supplying at least one water jet is preferably a preferably ring-shaped body located in the cleaning head, which preferably has holes as small water nozzles. Pressurized water can be supplied into the body and escapes through the holes provided. They preferably have a diameter of 0.5 mm to 1.5 mm, particularly preferably of approximately 0.8 mm. The holes are preferably aligned in such a way that they generate a water jet that runs essentially parallel to the inner wall of the cleaning head in the direction of the air flow within the cleaning head. The device for supplying at least one water jet is preferably attached to the inner wall of the cleaning head and is preferably extended all around the inner wall. It is designed in such a way that its design does not significantly reduce the air flow inside the cleaning head. It is preferably above the existing inlet openings for the High pressure jets are arranged. It is preferably intended as a flushing device.

In a further embodiment of the present invention, a device (140) for supplying compressed air (141) is provided within the cleaning head (80).

The possible embodiments of the device just described for supplying at least one water jet also apply to the compressed air supply installed inside the cleaning head. However, the device for supplying compressed air preferably has a connection for supplying compressed air. Compressed air can particularly preferably be supplied via a channel. The holes are preferably aligned in such a way, and preferably as small compressed air nozzles, that they generate at least one compressed air jet that runs essentially parallel to the inner wall of the cleaning head in a direction towards the discharge opening, i.e. preferably in the direction of an air flow generated in the cleaning head, or that particularly preferably runs essentially spirally along the inner wall of the cleaning head and propagates towards the discharge opening. For the spiral compressed air flow, the holes are preferably arranged slightly obliquely relative to an imaginary transverse plane through the cleaning head.

Particularly preferably, the described device for supplying at least one water jet and the supply of compressed air installed inside the cleaning head are implemented in one structural unit. The cleaning head is preferably connected to a collecting system for removing dirt and spray water at the discharge opening.

In a further embodiment of the present invention, the cleaning device (20) has a Drying unit (160) spaced apart from the cleaning head (80) in the running direction of the conveyor belt (1).

The dryer unit preferably has means for drying the treadmill. The dryer unit is preferably arranged in the same position transversely to the treadmill as the points on the treadmill targeted by the existing cleaning nozzles. The dryer unit is particularly preferably arranged in the same position transversely to the treadmill as the center of the main opening, i.e. arranged in a line parallel to the direction of travel with the center of the main opening. The dryer unit is preferably attached to the cleaning head.

In a further embodiment of the present invention, the dryer unit (160) has at least one air nozzle (161) directed towards the conveyor belt (1).

Preferably, the existing air nozzles are each attached, preferably in groups, to a holder by means of which the existing air nozzles can be aligned with the treadmill. Preferably, the dryer unit has several air nozzles in one, preferably several rows along the running direction of the treadmill. Particularly preferably, the dryer unit has two rows of air nozzles along the running direction of the treadmill, with each row preferably having two air nozzles. Preferably, different rows are arranged offset from one another.

The air nozzles present on the dryer unit are preferably designed to generate an air flow that is narrow at the nozzle opening and wide further away from the air nozzle, particularly preferably a conical air flow. They are preferably designed to generate an air pressure jet, preferably by compressed air in the range of preferably 0.5 bar to 6 bar, particularly preferably by compressed air of approximately 4 bar. They are preferably arranged in such a way that the air jets generated hit the areas wetted with liquid by the cleaning nozzles.

In a further embodiment of the present invention, if more than one air nozzle (161) is present, the existing air nozzles (161) are arranged such that they are directed towards the treadmill (1) from at least two different directions.

Preferably, the existing air nozzles are arranged such that the jet profiles at least partially overlap. Particularly preferably, the existing air nozzles are arranged such that they are directed at a common surface from at least two different directions.

In a further embodiment of the present invention, at least the cleaning head (80) and at least one of the existing cleaning nozzles (40) are attached to a carrier device (180) and can be moved transversely to the running direction of the conveyor belt (1).

Furthermore, an advantageous method for cleaning a conveyor belt (1) of a drying screen in a paper production plant with a cleaning device (20) is specified, wherein the cleaning device has a cleaning head (80) which has an interior, a discharge opening (84) and a main opening (81) facing the conveyor belt (1), comprising the step of - irradiating the conveyor belt (1) with at least one high-pressure jet (60) of a liquid, which is preferably generated at a position outside the cleaning head (80) by a cleaning nozzle (40).

By generating the high-pressure jet at a position outside the cleaning head, the Dirt and/or suspended matter etc. collected in the cleaning head cannot contaminate the cleaning nozzle. In particular, an air flow that is preferably present in the interior of the cleaning head cannot contaminate the cleaning nozzle with dirt and/or suspended matter etc. that it carries with it.

In a further preferred method, the cleaning head (80) additionally has at least one inlet opening (82) in the wall of the cleaning head (80) and at least one high-pressure jet (60) is irradiated from the outside onto the treadmill (1) through one of the inlet openings (82) present in the cleaning head (80).

The blasting through the cleaning head allows the main opening to be positioned very close to the belt. Nevertheless, the existing high-pressure jets can be jetted onto the treadmill at a preferably acute angle between the surface normal to the treadmill and the high-pressure jet. If the main opening is close to the treadmill so that there is only a small gap of preferably 5 mm to 20 mm, particularly preferably 8 mm to 14 mm, very particularly preferably approx. 10 mm between the treadmill and the edge of the main opening, the spray water and the resulting dirt are caught by the covering of the area being cleaned. On the other hand, if a negative pressure is generated at the discharge opening of the cleaning head (not covered by the claims), the negative pressure causing an air flow as suction from the main opening to the discharge opening, there is a stronger suction near the source of the spray water and dirt with the same suction power. In addition, if an overpressure is generated in the interior of the cleaning head near the main opening using a device for supplying compressed air, the resulting air flow in the direction of the discharge opening is significantly greater, because the escape of air through the now small gap between the main opening and the treadmill is essentially prevented.

In a further preferred method, when irradiating the treadmill (1) with more than one high-pressure jet (60), the high-pressure jets (60) radiate onto the treadmill from different directions.

Preferably, the high-pressure jets radiate onto the belt in such a way that the jets penetrate into the various recesses and/or pores of the treadmill. Particularly preferably, the high-pressure jets radiate a line parallel to the direction of travel of the treadmill, so that a point on the treadmill is cleaned by high-pressure jets from various directions as a result of the movement of the treadmill, preferably at short intervals. Preferably, the high-pressure jets present radiate onto an area that is close to the center of the outline of the main opening projected onto the treadmill. The high-pressure jets preferably carry out an almost spot cleaning of the treadmill.

In a further preferred method, the high-pressure jets (60) impinge on the conveyor belt (1) at a common impact point (61).

Preferably, the treadmill is cleaned at one point simultaneously with high-pressure jets from different directions.

In a further preferred method, the liquid intended for the high-pressure jets (60) is additionally heated.

Preferably, the liquid is heated to a temperature between 20° and 200°. The liquid is particularly preferably heated to approx. 60°. This means that the capillary effect in the sieve is much lower and the night drying is thereby significantly supported.

In a further method not covered by the claims, a vacuum source is additionally connected to the discharge opening of the cleaning head (80), so that an air flow (83) is produced from the main opening (81) towards the interior of the cleaning head (80).

The air flow is based on the principle of a vacuum cleaner. For example, the cleaning head used here could be compared to a wet vacuum cleaner. The suction effect preferably sucks in the air and/or water that is on the other side of the treadmill than the cleaning head. The vacuum source is, for example, a suction pump.

In a further preferred method, the air stream (83) transports away dirt and/or used water.

Dirt is particularly the dirt particles that are removed from the treadmill during cleaning.

Preferably, the air flow transports dirt and/or used water away via a pipe system of the carrier device. Preferably, the used water is treated for reuse.

In the method according to the invention, compressed air (101) is supplied via a device (100) for supplying compressed air in the region of at least one impact point (61), so that the liquid bouncing off the track (1) is deflected by the supplied compressed air (101) in the direction of the main opening (81).

Preferably, the compressed air is supplied at the main opening. Preferably, compressed air is supplied in such a way that a Air curtain is formed around the high-pressure jets striking the treadmill. Compressed air is preferably supplied via a plurality of air pressure nozzles at the main opening, with the supplied compressed air preferably converging towards the centre of the main opening and preferably generating a strong air flow towards the discharge opening of the cleaning head. The supplied compressed air preferably deflects spray water, which experience has shown to diverge parallel to the surface of the treadmill, and preferably dirt that mixes with the spray water, into the cleaning head. Compressed air in the range of preferably 1 bar to 600 bar, preferably 3 bar to 30 bar, particularly preferably 5 bar to 12 bar, and very particularly preferably approx. 6 bar is preferably used. These ranges preferably also apply to compressed air that is supplied using a supply device inside the cleaning head and/or that is used to dry the treadmill through one or more air nozzles of a drying unit. The devices for supplying compressed air and the drying unit are preferably set up for the use of corresponding pressures.

In the method according to the invention, an overpressure is generated in the region of at least one impact point (61) by supplying compressed air, wherein the overpressure also spreads into the interior of the cleaning head (80) and generates an air flow (83) which transports the rebounding liquid away through the interior of the cleaning head (80).

The overpressure is preferably in the same range as the compressed air supplied to create the air curtain.

The area of at least one impact point is preferably the space enclosed by the air curtain generated. The area of at least one impact point is preferably approximately the main opening of the cleaning head.

The spread of the excess pressure in the interior of the cleaning head preferably occurs as far as the discharge opening, after which an air pressure slightly above or equal to the ambient air pressure or normal pressure is established again. The air pressure therefore preferably decreases in the interior of the cleaning head from the area of at least one impact point to the discharge opening, since an equalization of excess pressure and the ambient air pressure takes place via the discharge opening.

Surprisingly, it has been discovered that by supplying compressed air, such an overpressure can be created in the area of at least one impact point and that this overpressure generates an air flow through the interior of the cleaning head. This air flow is sufficient to transport dirt and spray water to the discharge opening. The overpressure pushes the dirt and spray water out of the cleaning head in the direction of the discharge opening. For example, even a vertical transport path against gravity of more than 50 cm can be bridged at a pressure of approx. 6 bar.

It is also particularly advantageous if the cleaning head is a short distance from the treadmill. This short distance is preferably made possible by the inlet openings in the cleaning head. Contrary to expert expectations, despite the preferred presence of inlet openings, an air flow caused by the excess pressure occurs in the interior of the cleaning head, which can transport dirt and spray water away to the discharge opening. An expert would expect that the excess pressure generated escapes through the inlet openings and/or the gap between the main opening of the cleaning head and the treadmill and thus does not generate a sufficient air flow within the cleaning head and thus prevents the generation of a Overpressure in the interior of the cleaning head. A major advantage of this type of generation of an air flow in the interior of the cleaning head is that devices for generating a negative pressure, such as suction pumps, can be dispensed with. Overpressure sources are usually already present in the (paper manufacturing) factory, but negative pressure sources are rare. In an alternative not covered by the claims, it is also possible to combine the generation of an overpressure in the interior of the cleaning head and the connection of a negative pressure source to the discharge opening, whereby the air flow in the interior can be increased, although an additional component (negative pressure source) is required for this.

In a further preferred method, at least one water jet (121) is additionally generated within the cleaning head (80), which carries away dirt and used water.

The water jet is preferably generated in the direction of the air flow within the cleaning head. Preferably, a plurality of water jets are generated within the cleaning head, preferably in a ring shape on the inner wall of the cleaning head. Preferably, dirt deposits on the inner wall of the cleaning head are loosened by the at least one water jet and transported further in the direction of the air flow. Preferably, a water pressure of 4 bar to 6 bar is used for this purpose, particularly preferably a water pressure of 5 bar.

In a further preferred method, compressed air (141) is additionally supplied within the cleaning head (80), which carries away dirt and used water.

The effect of the previously described at least one water jet is preferably achieved in the same way by supplied compressed air inside the cleaning head. The effect is particularly preferably enhanced by the combined supply of compressed air and at least one water jet. The used water and the detached dirt particles are preferably transported away through the discharge opening into a collecting channel. This collecting channel is preferably washed out from time to time by fixed nozzles.

In a further preferred method, the compressed air (141) is supplied inside the cleaning head (80) in such a way that an air vortex is created.

Preferably, the air vortex is generated by using a large number of compressed air nozzles inside the cleaning head, which spray compressed air at a slight angle onto the inner wall of the cleaning head so that it propagates in a slightly spiral shape in the direction of the air flow inside the cleaning head. This effect preferably swirls the existing water and dirt and carries them away with the air flow. Preferably, a Venturi effect is generated by at least one change in the cross-section of the cleaning head inside the cleaning head.

In a further preferred method, after the treadmill (1) has been irradiated with at least one high-pressure jet (60) of a liquid, the treadmill (1) is additionally dried by a dryer unit (160) arranged downstream in the running direction.

The part of the treadmill that has been freshly cleaned is preferably dried by the drying unit.

In a further preferred method, the drying unit (160) radiates at least one jet of compressed air (162) onto at least one region of the conveyor belt (1).

Preferably, at least one conical jet of compressed air is generated via a suitably designed nozzle. The compressed air removes the water in the treadmill or the liquid used to clean the treadmill.

In a further preferred method, when using more than one compressed air jet (162), the compressed air jets (162) radiate onto regions of the treadmill (1) from at least two different directions.

Preferably, the various compressed air jets impinge on the belt in such a way that depressions and/or pores in the conveyor belt are irradiated with compressed air from different directions. Preferably, a point on the conveyor belt is irradiated with compressed air from different directions through the dryer unit in succession - due to its movement relative to the dryer unit. The angle enclosed by the air jets and the surface of the conveyor belt (analogous to W2) is preferably in the range between 15° and 45°, particularly preferably it is 30°. The pressure used to generate these air jets is preferably in a range from 0.5 bar to 6 bar, particularly preferably it is 4 bar.

In a further preferred method, when using more than one compressed air jet (162), the areas of the treadmill (1) irradiated by the compressed air jets (162) overlap at least partially.

With the methods described, the treadmill can be cleaned with minimal energy expenditure for the generation of compressed air and high-pressure jets as well as with minimal water consumption.

Fig. 1

eine Skizze einer erfindungsgemäßen Vorrichtung mit einem Reinigungskopf sowie einer außerhalb des Reinigungskopfes angeordneten Reinigungsdüse,

Fig. 2

eine Skizze einer erfindungsgemäßen Vorrichtung mit einem Reinigungskopf sowie einer außerhalb des Reinigungskopfes angeordneten Reinigungsdüse, wobei der Reinigungskopf eine Eintrittsöffnung für den von der Reinigungsdüse erzeugten Hochdruckstrahl aufweist,

Fig. 3a/b

eine Skizze einer erfindungsgemäßen Vorrichtung mit einem Reinigungskopf, einer außerhalb des Reinigungskopfes angeordneten Reinigungsdüse und einer Einrichtung zur Zuführung von Druckluft im Bereich des Auftreffpunktes des Hochdruckstrahls auf dem Laufband, ohne (3a) und mit (3b) einer Eintrittsöffnung für den Hochdruckstrahl.

Fig. 4

einen Querschnitt einer erfindungsgemäßen Vorrichtung mit einem Reinigungskopf, mehreren außerhalb des Reinigungskopfes angeordneten Reinigungsdüsen, einer Einrichtung zur Zuführung von Druckluft im Bereich des Auftreffpunktes des Hochdruckstrahls auf dem Laufband, einer Einrichtung zur Zuführung von Wasserstrahlen im Inneren des Reinigungskopfes sowie einer Einrichtung zur Zuführung von Druckluft im Inneren des Reinigungskopfes,

Fig. 5

eine Darstellung einer erfindungsgemäßen Vorrichtung, die zusätzlich eine Trocknereinheit aufweist,

Fig. 6

eine Darstellung einer erfindungsgemäßen Vorrichtung, die zusätzlich eine Trocknereinheit aufweist, jedoch keine Einrichtung zur Zuführung von Druckluft im Bereich des Auftreffpunktes des Hochdruckstrahls auf dem Laufband und

Fig. 7

eine Hilfsskizze, die weder maßstäblich noch winkeltreu die Definition für Winkel der Ausrichtung einer oder mehrere Düsen bezüglich veranschaulicht.

The invention will now be further illustrated by way of example with reference to drawings, in which:

Fig.1

a sketch of a device according to the invention with a cleaning head and a cleaning nozzle arranged outside the cleaning head,

Fig.2

a sketch of a device according to the invention with a cleaning head and a cleaning nozzle arranged outside the cleaning head, wherein the cleaning head has an inlet opening for the high-pressure jet generated by the cleaning nozzle,

Fig. 3a/b

a sketch of a device according to the invention with a cleaning head, a cleaning nozzle arranged outside the cleaning head and a device for supplying compressed air in the area of the impact point of the high-pressure jet on the conveyor belt, without (3a) and with (3b) an inlet opening for the high-pressure jet.

Fig.4

a cross-section of a device according to the invention with a cleaning head, several cleaning nozzles arranged outside the cleaning head, a device for supplying compressed air in the area of the impact point of the high-pressure jet on the conveyor belt, a device for supplying water jets inside the cleaning head and a device for supplying compressed air inside the cleaning head,

Fig.5

a representation of a device according to the invention, which additionally has a dryer unit,

Fig.6

a representation of a device according to the invention, which additionally has a dryer unit, but no device for feeding of compressed air in the area of the impact point of the high-pressure jet on the treadmill and

Fig.7

an auxiliary sketch which illustrates neither to scale nor with an angle conformal definition with respect to the orientation of one or more nozzles.

In Figure 1 a section of a paper production plant 2 is shown, indicated by a conveyor belt 1 running over a roller 21 (only shown in cross section). The cleaning device 20 according to the invention is shown in a slight perspective. In this exemplary embodiment, it consists of a cleaning head 80, which is shown here as a section of a cylinder. The cleaning head 80 is open on the underside. This opening is the main opening 81. The cleaning head is arranged vertically above the conveyor belt at a distance of 35 mm. A cleaning nozzle 40 is also part of the cleaning device 20, which is aligned with the conveyor belt and is arranged outside the cleaning head 80. A hose (not shown) connects the cleaning nozzle 40 to a high-pressure pump (not shown). The point of impact 61 and the center axis of the cleaning head are here on the tangential line of the conveyor belt 1 running off the roller 21.

When the cleaning device 20 is in operation, an air flow 83 is set inside the cleaning head via a pump connected to the discharge opening 84 or other means for generating suction - these components are not shown here. This creates an air flow 83 inside, indicated by a dashed arrow. Air, indicated by dashed arrows in the direction of the main opening 81, is sucked in from outside the pipe through the main opening 81. At the same time, a water-based air flow is created via the cleaning nozzle 40 and pump means (not shown). High pressure jet 60 is generated. This has a diameter of 0.15 mm, radiates onto the treadmill 1 and hits the impact point 61.

This arrangement cleans the belt at the point of impact 61 of dirt by the high-pressure jet 61. Since the treadmill 1 is moving, it is cleaned continuously. The dirt particles detached from the treadmill 1 and the spray water generated during cleaning are caught by the cleaning head and transported away by the air flow 83. This means that the detached dirt particles do not settle on the belt again and the water used for cleaning can largely be reused for cleaning after being reprocessed. By arranging the cleaning nozzle 40 outside the cleaning head 80, it is not exposed to the air flow 83, which transports dirt particles. Contamination of the cleaning nozzle 40 by detached dirt particles is therefore prevented by this arrangement.

In Figure 2 is a cleaning device according to the invention similar to that of Figure 1 shown, with the difference that now an inlet opening 82 is provided in the cleaning head. This inlet opening 82 is an oblique hole with a diameter of 0.25 mm. In addition, a difference to Figure 1 that the cleaning head is now positioned at a distance of 10 mm from the treadmill.

During operation of the cleaning device 20, an air flow 83 is generated within the cleaning head 80 and a high-pressure jet 60 (see description Figure 1 ). What is different here, however, is that the high-pressure jet 60 hits the treadmill 1 through the inlet opening 82 and consequently also through the main opening 81 at the impact point 61.

Due to the existing inlet opening 81, a smaller distance between the cleaning head 80 and the treadmill is possible in this exemplary embodiment. The air flow 83 created by the suction thus has an even stronger effect on the impact point 61, the location where the spray water and the dirt particles are created. Both the spray water and the dirt particles can therefore be removed more effectively via the cleaning head 80. In addition, the cleaning nozzle 40 is now even better protected against contamination by the dirt particles, since the cleaning head 80 acts like a protective shield for the cleaning nozzle 40.

In Figure 3a The cleaning device 20 according to the invention is similar to that of Figure 1 shown, with the essential difference that now two additional devices 100 for supplying compressed air 101 are arranged in the area of the impact point 61. These are indicated as air pressure nozzles 100. The air pressure nozzles are each supplied via a hose (not shown) that carries compressed air. The impact point 61 and the center axis of the cleaning head are located here in front of the tangential line of the conveyor belt 1 running off the roller 21, at a point at which the conveyor belt 1 rests on the roller.

When the cleaning device 20 is in operation, the air pressure nozzles each blast an air pressure jet 101 against the conveyor belt, so that the spray water, which during operation usually carries the detached dirt particles with it and sprays away essentially parallel to the conveyor belt 1 from the point of impact 61, hits the air pressure jets 101. The spray water bounces off the air pressure jets 101 and is thus directed in the direction of the main opening 81. The air jets 101 are also deflected via the conveyor belt 1 in the direction of the main opening 81. The collision of the air jets 101 and the air jets deflected on the material web generates an overpressure which causes an air flow 83 essentially vertically upwards within the cleaning head 80. With this air flow 83, the collected dirt and spray water is pushed upwards to the discharge opening 84 and through it.

The additionally installed device 100 for supplying compressed air 101 enables the spray water and the loose dirt particles to be diverted in the direction of the main opening 81. The air flow 83 generated in this way can therefore capture these very effectively. The loss of spray water and the risk of renewed contamination of the treadmill 1 or the cleaning nozzle 40 by loose dirt particles are greatly reduced. In addition, the use of compressed air alone simultaneously shields the spray and dirty water and removes it. No negative pressure is required within the cleaning head 80 to suck in the spray and dirty water.

In Figure 3b is a cleaning device 20 according to the invention similar to that of Figure 3a shown with the difference that the cleaning jet 60 radiates through an inlet opening 82 onto the treadmill 1 and this allows a closer positioning of the main opening 81 to the impact point 61 with the same angle of incidence of the cleaning jet 60 onto the treadmill 1.

When the cleaning device 20 is in operation, the small gap between the cleaning head and the conveyor belt 1 can result in an even stronger air flow 83, since the excess pressure created by the compressed air jets 101 in the area of the main opening 81 is forced even more strongly to adjust to the ambient pressure via the discharge opening 84 and not in any other way. In addition, dirty water and splash water are collected even more advantageously directly by the cleaning head 80.

• An der Hauptöffnung 81 ist eine Einrichtung 100 zur Zuführung von Druckluft 101 angebracht. Diese ist ein am Außenradius des Reinigungskopfes 80 angebrachter, die Hauptöffnung 81 umgebender, ringförmiger Hohlkörper mit in gleichen Abständen zueinander gebohrten Löchern als Luftzuführungsöffnungen 102 mit dem Durchmesser 0,8 mm. Die Löcher sind in einem Winkel von 30° relativ zur Ebene des Laufbands 1 gebohrt. Dieser Hohlkörper ist ein zu einem Ring gebogenes Rohr, dessen Enden miteinander luftdicht verschweißt sind und in welches Löcher als Luftzuführungsöffnungen sowie ein Anschlussloch zur Zuführung von Druckluft gebohrt sind. Zur Herstellung einer dieser Luftzuführungsöffnung wird zunächst das den Ring bildende Rohr durch eine Bohrung, die an der Außenseite des Rings ansetzt komplett durchbohrt, so dass durch eine Bohrung zwei Löcher in dem Rohrmantel entstehen. Das Austrittsloch an der Innenseite des Rings ist schräg nach unten auf den Ringmittelpunkt ausgerichtet. Der Grat an diesem Loch ist somit nicht auf der im Hohlraum des Rings liegenden Rohrfläche, sondern auf der Außenfläche. Dadurch kann der Grat sauber entfernt werden. Das andere, im Rohrquerschnitt gegenüberliegende Loch wird zugeschweißt. Auf diese Weise erhält man eine saubere Bohrung, welche als Luftzuführungsöffnung dienen kann. Würde ein Loch mit einem im Hohlraum des Rings liegenden Grat verwendet, könnten sich Unreinheiten in der Druckluft mit der Zeit an dem Grat festsetzen und das Loch würde nach einer gewissen Zeit verstopfen.
• Der Reinigungskopf weist zwei seitliche Eintrittsöffnungen 82 auf.
• Direkt über den Eintrittsöffnungen 82 ist als Einrichtung 120 zur Zuführung von Wasserstrahlen 121 im Inneren des Reinigungskopfes 80 ein hohler Ringkörper mit in gleichen Abständen zueinander gebohrten Löchern als Wasserstrahlöffnungen 122 mit dem Durchmesser 0,8 mm angebracht. Die Löcher sind vertikal nach oben und parallel zur Innenwand des Reinigungskopfes 80 gebohrt. Ein Wasseranschluss 123 ist an dem Ringkörper vorhanden.
• Über der Einrichtung 120 zur Zuführung von Wasserstrahlen 121 ist als Einrichtung 140 zur Zuführung von Druckluft 141 im Inneren des Reinigungskopfes 80 ein hohler Ringkörper mit in gleichen Abständen zueinander gebohrten Löchern als Luftzuführungsöffnungen 142 mit dem Durchmesser 0,8 mm angebracht. Die Löcher sind vertikal nach oben und parallel zur Innenwand des Reinigungskopfes 80 gebohrt. Ein Druckluftanschluss 143 ist an dem Ringkörper vorhanden.
• Im obersten Bereich der Zeichnung weist der Reinigungskopf 80 eine Biegung um 90° auf.
• Außerhalb des Reinigungskopfes 80 sind zwei gegenüberliegende Reinigungsdüsen 40 zur Erzeugung laminarer Hochdruckstrahlen 60 angebracht.

In Figure 4 another exemplary embodiment of the cleaning device 20 according to the invention is shown. Shown is a view of the interior of the cleaning head 80 (diameter: 228 mm; distance to the conveyor belt 1, not shown: 10 mm) and the components attached to it:

• A device 100 for supplying compressed air 101 is attached to the main opening 81. This is an annular hollow body attached to the outer radius of the cleaning head 80 and surrounding the main opening 81 with holes drilled at equal distances from one another as air supply openings 102 with a diameter of 0.8 mm. The holes are drilled at an angle of 30° relative to the plane of the treadmill 1. This hollow body is a tube bent into a ring, the ends of which are welded together in an airtight manner and in which holes are drilled as air supply openings and a connection hole for supplying compressed air. To produce one of these air supply openings, the tube forming the ring is first completely drilled through a hole that starts on the outside of the ring, so that two holes are created in the tube jacket through one hole. The exit hole on the inside of the ring is aligned diagonally downwards towards the center of the ring. The burr on this hole is therefore not on the pipe surface in the ring cavity, but on the outer surface. This allows the burr to be removed cleanly. The other hole, opposite in the pipe cross-section, is welded shut. This creates a clean hole that can serve as an air supply opening. If a hole with a burr in the ring cavity were used, impurities in the compressed air could settle on the burr over time and the hole would become blocked after a certain time.
• The cleaning head has two lateral inlet openings 82.
• Directly above the inlet openings 82, a hollow ring body with holes drilled at equal distances from one another as water jet openings 122 with a diameter of 0.8 mm is attached as a device 120 for supplying water jets 121 inside the cleaning head 80. The holes are drilled vertically upwards and parallel to the inner wall of the cleaning head 80. A water connection 123 is provided on the ring body.
• Above the device 120 for supplying water jets 121, a hollow ring body with holes drilled at equal distances from one another as air supply openings 142 with a diameter of 0.8 mm is mounted as a device 140 for supplying compressed air 141 inside the cleaning head 80. The holes are drilled vertically upwards and parallel to the inner wall of the cleaning head 80. A compressed air connection 143 is provided on the ring body.
• In the upper part of the drawing, the cleaning head 80 has a bend of 90°.
• Outside the cleaning head 80, two opposing cleaning nozzles 40 are mounted to generate laminar high-pressure jets 60.

When the cleaning device 20 is in operation, the cleaning nozzles 40 each blast a high-pressure jet 60 consisting of water at a pressure of 450 bar onto a common impact point 61 from two different directions. The high-pressure jets 61 clean the belt. Furthermore, compressed air 101 (shown as an example only for two air supply openings 102, even if compressed air 101 flows out of all air supply openings 102) is fed via the air supply openings 102 into the ring body of the device 100 for supplying compressed air 101. The individual jets of compressed air 101 that are created thereby converge to the vertical center axis of the cleaning head 80 and together form an air curtain 103 that directs the resulting spray water between the cleaning head 80 and the treadmill 1. The compressed air 101 is further deflected itself and then acts in the direction of the interior of the cleaning head 80. A strong vertical updraft (only partially indicated by dashed arrows, whereby an arrowhead does not mean the end of the air flow) results in the interior of the cleaning head 80 due to the overpressure generated by the compressed air of the air curtain 103 in the interior of the cleaning head 80. Due to the small gap between the treadmill 1 and the main opening 81, the overpressure results in an air flow 83 in the direction of the discharge opening 84, which is strong enough to transport dirt and spray water to the discharge opening. The spray water (exemplarily shown by meandering, continuous lines that originate from the impact point 61), which normally diverges along the plane of the treadmill 1, is blocked by the air curtain 103 and deflected vertically upwards into the cleaning head 80. Water is fed into the ring body of the device 120 for supplying water jets 121. The resulting individual water jets 121 flush the inner wall of the cleaning head 80. The water pressure used here is 5 bar. Compressed air is fed into the ring body of the device 140 for supplying compressed air 141. The resulting individual compressed air jets 141 drive the water and the detached dirt particles forward in the direction of the discharge opening 84.

Cleaning by using more than one high-pressure jet 60 is more effective than cleaning with just one jet. The high-pressure jets 60 penetrate from different directions into pores and recesses of the treadmill 1, thereby achieving a more thorough cleaning. The design of the device 100 for supplying compressed air 101 as a hollow ring body with air supply openings 102 allows the creation of an air curtain 103 that encloses the spray water. The devices 120 and 140 shown here for supplying Water jets 121 and 141 keep the interior and inner walls of the cleaning head 80 clean.

In Figure 5 1 shows an example of a cleaning device 20 according to the invention which, in contrast to the cleaning devices 20 shown previously, has three cleaning nozzles 40 (only two are visible, one is hidden) for generating laminar high-pressure jets 60 and three inlet openings 82 (only one is visible, two are hidden) in the cleaning head 80. One is aligned opposite to the running direction of the treadmill 1 and the other two are aligned against each other transversely to the treadmill 1. The impact points 61 of the three high-pressure jets 61 are approximately at the tangential point of the treadmill 1 and the roller 21 and they are each 2 mm apart from each other in a line along the running direction of the treadmill 1. In addition, a carrier device 180 with a collecting channel system integrated therein is shown as an example. In contrast to the cleaning devices 20 shown previously, the cleaning device 20 shown here is equipped with a dryer unit 160. This has four air nozzles 161 along the running direction of the treadmill 1, which are each offset from two different directions or with two different angles of incidence onto the treadmill 1.

When the cleaning device 20 is in operation, the air nozzles 161 spray conical air jets 162 onto the treadmill 1, thus drying the area of the treadmill 1 that has just been cleaned and is therefore wet. The angle enclosed by the air jets and the surface of the treadmill 1 is 30°. The jets are generated by compressed air at a pressure of 4 bar. The spray and rinsing water collected and drained by the cleaning head 82 as well as the detached dirt particles are washed out of the collecting channel system with the aid of rinsing jets and scrapers. During cleaning, the cleaning device is moved transversely to the Running direction of the treadmill 1 along the support device 180 via a motor.

The described alignment of the high-pressure jets 60 allows the available jet energy to be concentrated on a small area. The dryer unit arranged downstream of the cleaning components ensures rapid drying of the cleaned conveyor belt 1. The arrangement of the air nozzles 161 along the conveyor belt path creates a wide air curtain in the direction of travel.

In Figure 6 A cleaning device 20 according to the invention is shown as an example, which in contrast to the cleaning device from Figure 5 has no inlet openings 82 in the cleaning head 80. The main opening 82 is therefore at a greater distance from the conveyor belt 1 so that the high-pressure jets 60 generated by the cleaning nozzles 40 can impinge on the conveyor belt 1 unhindered. There is also no device 100 for supplying compressed air 101. Furthermore, the dryer unit 162 is equipped with six air nozzles 161 arranged offset from one another.

In this embodiment, the spray water and the detached dirt particles are sucked in exclusively by a suction - the air flow 83 - in the cleaning head 80, which also draws in air from the area around the main opening 81 (indicated by a truncated cone with a dashed outline).

This simplified design is a more cost-effective variant of the cleaning device 20. The use of six instead of four air nozzles 161 in the drying unit 160 allows even faster drying of the area of the treadmill 1 that has just been cleaned. However, it may be necessary to purchase a new vacuum pump.

In Figure 7 it is shown which angles W1 and W2 can be adjusted for alignment. Three high-pressure jet nozzles 40 are shown, each of which emits a high-pressure jet 60 onto three different impact points 61. The running direction 11 of the treadmill (with arrow) and the projections 62 of the high-pressure jets onto the treadmill 1 are shown in dashed lines. W1 is the angle 63 between the running direction and the projection, W2 is the angle 64 between the treadmill surface and the high-pressure jet.

With the invention newly presented here, it is possible for the first time to provide a cleaning device which, through the individual features but also through the interaction of the features, enables a significant advance in, for example, dry screen cleaning. For example, continuous cleaning without an intermediate drying phase of the dry screen is possible for the first time. For example, through the small area on which the cleaning jets hit the treadmill in conjunction with the cleaning head that can be positioned close to the treadmill - made possible by the inlet openings - the cleaning device achieves a high cleaning effect while at the same time effectively removing the dirt - through the overpressure - and in addition the drying unit quickly dries the treadmill - aided by the small area that is wetted. But it is not just the interaction, but also the use of just one or individual of these inventive features that sets this cleaning device apart from the state of the art.

Reference symbols

1 Treadmill 2 Paper manufacturing plant 11 Running direction 20 Cleaning device 21 role 40 Cleaning nozzle 60 High pressure jet 61 Impact point 62 Projection of the high-pressure jet onto the treadmill surface 63 W1 64 W2 71 Heat exchanger 80 Cleaning head 81 Main opening 82 Entrance opening 83 Airflow 84 Discharge opening 100 Device for supplying compressed air 101 Compressed air 102 Air supply opening 103 Air curtain 120 Device for supplying water jets 121 Water jet 122 Water jet opening 123 Water connection 140 Device for supplying compressed air 141 Compressed air 142 Air supply opening 143 Compressed air connection 160 Dryer unit 161 Air nozzle 162 Compressed air jet 180 Carrier device

Claims (12)

1. Cleaning apparatus (20) for cleaning a surface (1), comprising

   at least one cleaning nozzle (40) for generating a high-pressure jet (60) of a liquid having an incidence point (61) on the surface, at least one cleaning head (80) having a discharge opening (84) and a main opening (81) that faces towards the surface (1), and at least a first device (100) for supplying compressed air (101) in the region of at least one incidence point (61) of at least one high-pressure jet (60) on the surface,

   wherein

   the compressed air (101) is supplied via the first device (100) for supplying compressed air (101) in the region of the incidence point (61), such that liquid bouncing off the surface is diverted towards the main opening (81) by the supplied compressed air (101) and a positive pressure is generated in the region of the incidence point (61) by the supplying the compressed air, wherein the positive pressure also spreads into the interior space of the cleaning head (80) and generates an airflow (83) that takes away the bouncingoff liquid through the interior space of the cleaning head (80) to the discharge opening (84),

   characterized in that

   the airflow is generated without the presence of a device for generating a negative pressure.
2. Cleaning apparatus (20) according to claim 1, wherein the surface is the running belt (1) of a drying screen in a paper production installation (2).
3. Cleaning apparatus (20) according to one of the previous claims, wherein
   the cleaning apparatus (20) has a drier unit (160) spaced apart from the cleaning head (80) in the running direction of the surface.
4. Cleaning apparatus (20) according to one of the previous claims, wherein

   the first device (100) for supplying compressed air comprises an annular hollow body disposed at the main opening (81), and/or

   a second device (140) for supplying compressed air is provided, which comprises an annular hollow body, which is provided inside the cleaning head.
5. Cleaning apparatus (20) according to one of the claims 1 to 3, wherein

   a second device (140) for supplying compressed air (141) inside the cleaning head (80), which takes away dirt and used water towards the discharge opening (84), is provided, wherein

   the compressed air (141) is supplied inside the cleaning head (80) in such a way that an air vortex is created.
6. Cleaning apparatus (20) according to one of the

   previous claims, wherein

   a device (120) for supplying water jets (121) is provided inside the cleaning head (80), wherein the generated water jets (121) are aligned substantially in a direction towards the discharge opening (84).
7. Method for cleaning a running belt (1) of a drying screen in a paper production installation having a cleaning apparatus (20), wherein the cleaning apparatus has a cleaning head (80), which has an interior space, a discharge opening (84), and a main opening (81) that faces towards the running belt (1), comprising the step - spraying the running belt (1) with at least one high-pressure jet (60) of a liquid, which is generated by a cleaning nozzle (40), wherein

   in addition compressed air (101) is supplied by a device (100) for supplying compressed air in the region of at least one incidence point (61), such that liquid bouncing off the running belt (1) is diverted towards the main opening (81) by the supplied compressed air (101),

   by the supplying of compressed air, a positive pressure is generated in the region of at least one incidence point (61), wherein the positive pressure also spreads into the interior space of the cleaning head (80) and generates an airflow (83) that takes away the bouncingoff liquid through the interior space of the cleaning head (80),

   characterized in that

   the airflow is generated without the presence of a device for generating a negative pressure.
8. Method according to claim 7, with the further step of heating the liquid provided for the high-pressure jets (60) .
9. Method according to claim 7 or 8, with the further step generating at least one water jet (121) inside the cleaning head (80), which takes away dirt and used water.
10. Method according to one of claims 7 to 9, with the further step of

    supplying compressed air (141) inside the cleaning head (80), which takes away dirt and used water towards the discharge opening (84),

    wherein the compressed air (141) is supplied in the interior of the cleaning head (80) preferably in such a way that an air vortex forms.
11. Method for cleaning a running belt (1) according to one of claims 7 to 10, with the further step of drying the running belt (1) by a drier unit (160) located downstream in the running direction after the running belt (1) has been sprayed by at least one high-pressure jet (60) of a liquid.
12. Method for producing paper in a paper production installation with a running belt of a drying screen, wherein the running belt is cleaned with a method according to one of claims 7 to 11.

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