Steam cleaning apparatus for cleaning industrial plates

Abstract

Steam-cleaning apparatus (11) for cleaning industrial plates comprising a detergent-applying station (13); a steam-cleaning station (15); a suction station (17); a drying station (19); movement members (21) defining a transport line (23) for transporting industrial plates (100) through said stations (13, 15, 17, 19); wherein the movement members (21) comprise at least one belt feed assembly (25), located below relative to the transport line (23), and at least one roller compression assembly (27), located above relative to the transport line (23), said belt feed assembly (25) and said roller compression assembly (27) cooperating with each other to cause rectilinear feeding of the plates (100) through said stations (13, 15, 17, 19) along a feeding plane (29).

Description

Technical Field

[0001] The present invention relates to an apparatus for cleaning industrial plates made of any material, particularly metal-based or plastic-based single-material or multi-material plates, including those comprising both mono-layered or multi-layered combinations of metal and plastic materials.

[0002] The apparatus is suitable for cleaning plates in the form of coils or discrete parts that can be subjected to a cleaning treatment based on the use of steam.

[0003] In the context of the present invention, the term steam is used, both in the description and in the claims, to refer without distinction both to steam alone and to steam mixed with detergents.Prior Art

[0004] Industrial metal plates, hereafter referred to as plates, are widely used for various applications such as construction, transportation, manufacturing industry, etc.

[0005] These plates can be made of various materials, such as graphite, metals, metal alloys in general, plastics, polymeric materials and metal-plastic blends. These plates are predominantly made from laminated materials with a thickness of 0.1 to 10.0 mm or more.

[0006] The material for forming the plates is usually unwound from a coil and has its surfaces contaminated with various rolling and drawing greases, dienes, emulsions and other foreign substances.

[0007] The production of the plates starts from a sheet of raw material, typically unwound from a coil. A variety of mechanical processes such as forming, separating, cutting, welding, straightening, etc. are required to obtain a complete plate. As is known, all these mechanical processes require the use of lubricating oils, solvents and fluxing agents to obtain a good quality product. At this point, after the plate has been formed, as an undesirable consequence of the mechanical operations carried out to make the plate itself, halos such as oil stains, lubricant stains and solidified haloes of volatile liquids and machining residues such as metal and / or plastic shavings and filings will be present on the surface of the plate, which if not removed will adversely affect the quality of the final product. The surface of the plate that has not been conveniently cleaned may present hydrophilic and hydrophobic zones, resulting in uneven performance once the plate has been assembled in a stack; therefore, the plate must necessarily be cleaned for the removal of the aforementioned halos and residues of machining and impurities in general present on the surface of the plate after manufacturing thereof has been completed.

[0008] The main challenge in cleaning metal or multi-material plates is the mostly invisible chemical film residues on the surfaces. These are oils, greases, emulsions and other chemicals, the composition of which is often unknown. These non-specific contaminations require a cleaning solution that guarantees reliable removal as needed.

[0009] Currently, plate cleaning methods are based on various technologies such as laser cleaning, cryogenic blasting, plasma cleaning, ultrasonic cleaning, ice cleaning, wet chemical cleaning with solvents, and steam jet cleaning.

[0010] Both laser and cryogenic blasting are methods that can be used to remove stains and oxides as well as chemical contaminating films and particles from welded seams in seconds. However, these methods operate over small, circumscribed areas and therefore take a long time to clean the complete flat surface of bipolar plates. These methods are also particularly expensive in terms of equipment and during their application. Not the least drawback of cryogenic blasting is that CO 2 is known to be harmful to health and the environment. In addition, cryogenic technology has the disadvantage of being particularly aggressive and can irreparably damage plate surfaces, especially plastic plates.

[0011] Plasma and ultrasonic cleaning systems are very efficient cleaning systems, but they have the disadvantage of requiring complex and very large equipment, which require complex and expensive maintenance. These systems are therefore uneconomical for use in large-scale production.

[0012] Chemical wet cleaning with solvent involves immersing the plates in a container filled with water and chemical solvents and achieves effective removal of oils, greases and particles. However, this process has low efficiency in cleaning emulsions, sludges and oxides. Furthermore, chemical cleaning by immersion in water mixed with solvent is only possible to a limited extent and with complex handling equipment for inserting and removing the plates from the container in which the cleaning liquid is present. The long drying phase required to remove the residual water and solvents after immersion is a further drawback of this technology.

[0013] Patent document CN116099811A discloses a steam cleaning apparatus for cleaning plates that comprises a conveyor belt, a cleaning chamber, a drying chamber and a cleaning tool used to accommodate a bipolar plate. The cleaning tool is attached to the conveyor belt, which extends through the cleaning chamber and the drying chamber. In the cleaning chamber there is a tank of water in which the tool accommodating the plate is immersed. An air blower is installed in the drying chamber. This method is suitable for cleaning particularly thin and narrow plates. For medium-thick steel plates and large steel plates, however, it is difficult to achieve a high quality of surface cleanliness, due to the difficulties in ensuring smooth transport of the plates. This method also causes scratches on the surface of the plates.

[0014] A device for cleaning metal sheets is also known from patent document CN108515463A. A high-pressure water jet cleaning line with a drying device to remove residual water stains is described. However, the vibrations that are generated on the plates due to the impact of the air jet negatively affect the cleaning effect. This method is also suitable for cleaning small plates. For medium-thick metal plates and large metal plates, difficulties arise in regular transport, resulting in scratches on the surface and uneven cleaning of the plate surface.

[0015] Document US2013228195A1 discloses a panel cleaning method that uses steam and water mixed with a cleaning fluid. The method described includes a steam sprayer to spray steam onto the panel and a cooling water sprayer to spray cooling water onto the panel. A roller brush is used to remove dirt and halos. The use of this system has the disadvantage that if the cooling water is not completely removed from the surface of the panels before the drying phase, especially in the case of panels with a shaped or irregularly shaped surface, this can lead to halos or stains and uneven cleaning of the surface. In addition, the removal of dirt with the roller brush may cause scratches on the surface of the panels.

[0016] Document WO2019180123A1 discloses an equipment for processing planar substrates, cardboard or sheet metal, with a side suction device to remove impurities from the surface of the substrates. The equipment has transport means designed to move the substrates throughout the equipment. On leaving the equipment, the substrates are pressed onto the transport means by means of pressing rollers in order to facilitate the stacking of the substrates in the packages. The side suction port has the drawback of not being able to suck in all the impurities present on the substrates, as it is impossible to remove impurities from the areas in contact with the transport means.

[0017] The Applicant found that known cleaning plants that substantially only use steam (or steam and other substances as a cleaning element) are particularly rigid and substantially not adaptable to variations in the size and format of the objects to be cleaned.

[0018] Furthermore, the Applicant found that cleaning plants that use steam alone are generally used to clean only plate coils (yet to be separated) and not individual plates.

[0019] There is therefore a need for providing plate cleaning devices that can clean the surfaces of the plates efficiently, in any format (single plate or strip of plates) without damaging the plate surfaces.

[0020] The object of the invention is to overcome the drawbacks outlined above.

[0021] More particularly, an object of the present invention is to provide an apparatus for in-line cleaning of individual plates.

[0022] A still further object of the invention is to provide an apparatus for cleaning plates that has a system for effectively maintaining the position of the plates on the conveyor belt during the cleaning steps.

[0023] Another object of the invention is to provide an apparatus for cleaning bipolar plates that guarantees high levels of cleanliness and is versatile for use in the production process.

[0024] A further object of the invention is to provide an apparatus for cleaning plates of the aforementioned type that allows the plates to be moved between the various cleaning chambers without causing damage, such as scoring, abrasion or deformation, during all cleaning operations, thus guaranteeing the flatness of the plates at the end of the process.

[0025] Another object of the present invention is to provide such an apparatus that is easy to implement and maintain.

[0026] A still further object of the present invention is to provide an apparatus that guarantees the cleaning of plates at a speed that does not affect the production cycle of the plates themselves.

[0027] A further object of the present invention is to provide an apparatus that ensures the cleaning of plates while minimizing the consumption of cleaning fluid.

[0028] These and other objects are achieved with the apparatus according to the invention as defined in the appended claims.

[0029] Further features of the plate-cleaning apparatus according to the present invention will become clearer from the following detailed description, referring to a preferred embodiment thereof provided purely by way of example.Summary of the invention

[0030] The apparatus for cleaning plates according to the invention mainly comprises a detergent-applying station, a steam-cleaning station, a suction station, a drying station and movement members defining a transport line for transporting plates through said stations.

[0031] According to the invention, the apparatus is provided with movement members comprising at least one belt feed assembly located below relative to the transport line and at least one roller compression assembly located above relative to the transport line.

[0032] Still according to the invention, the belt feed assembly and the roller compression assembly cooperate with each other to cause rectilinear feeding of the plates through said detergent-applying, cleaning, suction and drying stations, along a feeding plane.

[0033] In a preferred embodiment of the invention, the steam cleaning station and the suction station comprise a cleaning and suction chamber in common, and said stations define, in combination with each other, a corresponding cleaning and suction integrated station. Advantageously, and as will become clearer from the description below, thanks to this configuration, delivery of the cleaning steam and suction of the delivered steam that has brushed the surfaces of the plates passing through said cleaning and suction station take place simultaneously.

[0034] According to a preferred embodiment of the invention, the temperature of the steam is preferably higher than 80°C and even more preferably lies within the range 80-110°C.

[0035] According to a preferred embodiment of the invention, the apparatus comprises at least one pair of detergent-applying stations and at least one pair of cleaning and suction stations. Also, said four stations are preferably alternated with each other, the detergent-applying stations being arranged upstream of the cleaning and suction stations.

[0036] Still according to a preferred embodiment of the invention, the belt feed assembly comprises a motor-driven conveyor belt. The motor-driven conveyor belt is preferably equipped with a pair of upper rollers, one of which is a motor-driven roller, and the other one is an idle roller, and a lower idle roller, a belt being provided around said three rollers. Furthermore, the rollers of said belt feed assembly are arranged horizontally with their respective rotation axes mutually parallel and perpendicular to the rectilinear direction of feeding of the plates on the feeding plane. In this way, a substantially horizontal portion for transporting the plates along the feeding plane passing through the stations of the apparatus is defined on the belt. Also, the belt feed assembly is preferably configured in such a way that the axes of rotation of the rollers of the belt feed assembly intersect an imaginary plane located perpendicularly to said axes, substantially at the vertices of an equilateral triangle.

[0037] Still according to a preferred embodiment of the invention, the roller compression assembly comprises idle rollers arranged with their respective rotation axes mutually horizontal and mutually parallel and perpendicular to the rectilinear direction of feeding of the plates on the feeding plane. The idle rollers of the compression assembly are susceptible to take a proximal configuration relative to the belt feed assembly cooperating with said compression assembly and a distal configuration relative to said belt feed assembly.

[0038] Preferably, the roller compression assembly and the distance between the axes of said rollers in a direction perpendicular to said axes are chosen so that the rollers of the compression assembly carry out a substantially simultaneous compression onto the upper surface of a plate arranged horizontally between said assemblies, at the substantially horizontal portion defined on the belt of the belt feed assembly, between the motor-driven roller and the idle roller.

[0039] Preferably, according to the invention, the apparatus comprises a plurality of said roller compression assemblies. Even more preferably, some of said compression assemblies can take said proximal and distal configurations by virtue of an actuator, whereas other compression assemblies are equipped with elastic means capable of causing switching of said rollers from said distal configuration to said proximal configuration and to oppose, with their elastic resistance, the switching from said proximal configuration to said distal configuration.

[0040] In a preferred embodiment of the invention, the movement members comprise a plurality of belt feed assemblies and a corresponding plurality of compression assemblies, and the switching from said proximal configuration to said distal configuration and vice versa is obtained by means of an actuator in the first and last of said compression assemblies, whereas the switching from said distal configuration to said proximal configuration is obtained by means of elastic means in the intermediate compression assemblies.

[0041] Preferably, according to the invention, downstream of the detergent-applying stations and downstream of the cleaning and suction stations there is provided a liquid removal station. Said liquid removal station comprises a liquid removal chamber housing a pair of compressed-air diffusers. Advantageously, the compressed-air diffusers are capable of generating a laminar-type compressed air flow, i.e. substantially an air blade. Furthermore, preferably, the air blade generated by the compressed-air diffusers is directed against the surfaces of the opposite sides of the plates passing through said liquid removal station.

[0042] Downstream of the liquid removal station, where provided, there is also advantageously provided a drying chamber. Preferably, the drying chamber is provided with one or more heated-air diffusers. Even more preferably, the drying chamber is provided with a pair of heated-air diffusers, a first diffuser being located above relative to the region at which the plates pass through said drying chamber and a second diffuser being located below relative to the region at which the plates pass through said drying chamber.

[0043] In a preferred embodiment of the invention, a plate to be subjected to a cleaning cycle in the apparatus according to the invention undergoes a treatment involving, in order, mainly a step of feeding the plate to the cleaning apparatus, a step of applying some detergent onto the plate, a step of steam-cleaning the plate, a step of sucking dirt off the plate, a step of removing the liquid from the plate, a step of drying the plate and a step of unloading the plate.

[0044] In a preferred embodiment of the invention, the cleaning apparatus is mainly equipped with a loading station, a detergent-applying station, a cleaning station, a suction station, a liquid removal station, a drying station and an unloading station.

[0045] The cleaning apparatus further comprises, preferably, a feeding plane which runs through all the aforesaid plate-treatment stations. The feeding plane is preferably substantially horizontal and preferably comprises movement members for transferring the plates and guiding the rectilinear feed of said plates, without the plates becoming deformed or damaged in any way.

[0046] According to the invention, the apparatus may comprise any number of detergent-applying stations, cleaning stations and suction stations. In addition, the cleaning stations and the suction stations are preferably integrated with each other and comprise a cleaning and suction chamber in common. Said stations, when more than one in number, will preferably be arranged alternately, whereby a cleaning and suction integrated station is always provided immediately downstream of each detergent-applying station.

[0047] Still referring to a preferred embodiment of the invention, two detergent-applying stations and two cleaning and suction stations, arranged alternately, are provided. In this way, each plate passing through the cleaning apparatus will meet, in order, in its travel along the feeding plane of the plates through the treatment stations, a first detergent-applying station, a first cleaning and suction station, a second detergent-applying station, and a second cleaning and suction station.

[0048] In a preferred embodiment of the invention, the loading station precedes all other stations and includes a loading unit at the entrance of the apparatus. In this preferred embodiment of the invention, the function of the loading unit is substantially to transfer a plate from the actual loading area, i.e. from the area where the plate is loaded onto the loading unit, to a first treatment station of the cleaning apparatus. The loading unit therefore essentially defines, in this preferred embodiment of the invention, the initial portion of the feeding plane and therefore the starting zone for the feeding movement of the plates through the stations of the apparatus.

[0049] When a plate arrives on the loading unit, the loading unit can either already be in motion or be started by the time on it there is at least one plate to be cleaned. A plate to be subjected to a cleaning cycle by means of treatment within the apparatus according to the invention, can be made to arrive on said loading unit, i.e. loaded onto said loading unit, either manually by an operator who, for example, takes the plates from an adjacent stock, or mechanically by means of an automated positioner, e.g. a robotic mechanical arm. The loading unit can be started manually or be started by a control signal from an electronic control unit receiving a signal indicating the presence of a plate on the loading unit and generated by a sensor, for example, a photocell.

[0050] Preferably, according to the invention, a lateral guide is provided at the loading unit, to ensure the correct alignment of the plates on the plane defined on the loading unit. The guide is preferably adjustable at least transversely, to allow the loading unit to be adapted to plates of different width. The adjustment of the guide can take place either manually, for example by acting onto special screws that fix the guide to the frame of the apparatus, or mechanically, for example, by means of one or more actuators electrically controlled by an electronic control unit that processes the signal generated by a sensor measuring the transverse dimension, i.e., the width, of the plates. The at least one actuator can be, for example, of the pneumatic, hydraulic or electromechanical type.

[0051] In a preferred embodiment of the invention, the loading unit comprises a motor-driven conveyor belt equipped with a pair of rollers, one of which is a motor-driven roller and the other one is an idle roller, and a belt made of a plastic material, preferably a silicone material, or rubber, which rotates about said rollers. In addition, the idle roller is actuated by the movement imparted by the belt, which is in turn entrained by the motor-driven roller.

[0052] The rollers have mutually horizontal and mutually parallel axes perpendicular to the rectilinear direction of feeding of the plates on the feeding plane of the cleaning apparatus. In a preferred embodiment of the invention, the motor-driven roller is located proximal to the first treatment station of the cleaning apparatus and the idle roller is located in a distal position relative to said first station. In addition, still according to this preferred embodiment of the invention, the distance between the rotation axis of the idle roller and the rotation axis of the motor-driven roller is adjustable to place the belt in the correct tensioning state. Idle counter-rollers can be provided below the belt, in contact with the surface of the belt side opposite the belt side on which the plates lie. The idle counter-rollers mainly have the purpose of keeping the belt flat, preventing it from bending under the weight of the plates. The number of the idle counter-rollers will be proportional to the length of the loading unit and the rigidity of the belt.

[0053] A plate loaded on the loading unit arranged at the entrance of the cleaning apparatus is then transferred from said loading unit towards a first detergent-applying station.

[0054] According to a preferred embodiment of the invention, a detergent-applying station comprises a detergent-applying chamber in which the detergent is applied to the transiting plate, preferably to both surfaces of the opposite sides of said plate.

[0055] When passing from the loading unit, where provided, to a first detergent-applying chamber, the plate encounters a first belt feed assembly defining a portion of the feeding plane located downstream of the portion defined by the loading plane in the direction of feeding of the plates in the apparatus.

[0056] According to a preferred embodiment of the invention, the first belt feed assembly encountered by the plates in the apparatus mainly comprises a motor-driven conveyor belt equipped with a pair of upper rollers, one of which is a motor-driven roller and the other one is an idle roller, and a lower idle roller. The rollers of the intermediate feed assembly are arranged horizontally with their respective rotation axes mutually parallel and perpendicular to the rectilinear direction of feeding of the plates on the feeding plane. A belt made of a plastic material, preferably a silicone material, or rubber is provided about the rollers. The idle rollers are also actuated by the movement imparted by the belt, which is in turn entrained by the motor-driven roller.

[0057] In a preferred embodiment of the invention, the rotation axes of said rollers intersect an imaginary plane located perpendicularly to said axes, substantially at the vertices of an equilateral triangle.

[0058] According to the invention, at said first belt feed assembly, the plate undergoes a compressive action from top to bottom, against the surface of the conveyor belt, in a direction substantially perpendicular to the feeding plane of the plates in the apparatus.

[0059] Such compression is preferably caused by a pair of idle rollers, mounted with their axes mutually parallel and perpendicular to the direction of feeding of the plates in the apparatus. The idle rollers are associated with an actuator, for example, of the pneumatic, hydraulic or electromechanical type. The actuator is capable of making the idle rollers take a distal configuration relative to the surface of the feeding plane and a proximal position relative to said plane, or vice versa. The switching from a configuration to the other one and vice versa can take place, for example, by virtue of a stroke of the actuator in the vertical direction. In other embodiments, it will be possible to provide that the actuator operates along a direction other than the vertical direction, and that the vertical movement of the idle rollers is obtained by means of mechanical members such as a lever system associated with the actuator.

[0060] The distal configuration of the actuator corresponds to the condition in which the idle rollers are lifted relative to the conveyor belt and between the surface of the idle rollers and the surface of the belt there is provided a gap sufficient to allow free passage of a plate loaded on the loading unit and approaching the first detergent-applying chamber. The proximal configuration of the actuator corresponds to the condition in which the idle rollers are lowered and pressed against the upper surface of the plate passing through said idle rollers and the underlying intermediate assembly. In this configuration, the plate is substantially prevented from rotating or moving transversely to the rectilinear direction of feeding on the feeding plane and, in addition, the flat configuration of the plate is advantageously preserved, avoiding bending or other deformations.

[0061] According to a preferred embodiment of the invention, at the loading unit there is provided at least one sensor for measuring the thickness of the transiting plates to be cleaned. The signal generated by said at least one sensor is processed by an electronic control unit, which controls driving of the actuator depending on the thickness of the plates. The length of the actuator stroke and the relative positions taken by the idle rollers with respect to the surface of the belt are therefore determined by the electronic control unit, which has processed the signal coming from the at least one sensor sensing the thickness of the plates arriving at the first belt feed assembly.

[0062] Advantageously, according to the invention, the pressure exerted by the idle rollers on the transiting plate and counteracted by the belt of the first belt feed assembly, generates, between the plate and said belt, sufficient friction to ensure straight and jerk-free travel, with essentially constant speed, of the plates along the apparatus.

[0063] The actuator is also driven by the signal processed by an electronic control unit, which receives a signal coming from a sensor sensing the presence of the plate in the position appropriate for undergoing compression. The presence sensor can be provided, for example, at the exit from the first intermediate feed assembly, so as to intercept the front edge of the plate advancing along the cleaning apparatus.

[0064] In a preferred embodiment of the invention, in the cleaning cycle, each plate passes through a first detergent-applying chamber, a first cleaning and suction chamber, a second detergent-applying chamber and a second cleaning and suction chamber.

[0065] According to the invention, it is possible to provide a single detergent-applying chamber and a single cleaning and suction chamber arranged in succession, or any number of such chambers, preferably in an alternating combination having a cleaning and suction chamber immediately downstream of each detergent-applying chamber.

[0066] According to a preferred embodiment of the invention, downstream of the last cleaning and suction chamber there is provided a station for removing the liquid formed on the plates, said station being preferably adapted to generate compressed air blades directed towards the surface of the opposite sides of the transiting plates.

[0067] The cleaning apparatus according to the invention preferably has a hot-air drying station, equipped with diffusers capable of delivering hot air on the surfaces of the opposite sides of the transiting plates. This drying station is preferably located downstream of the station, where provided, in which compressed air blades are generated.

[0068] Downstream of the drying station there is provided a station for unloading the plates that have undergone the cleaning cycle. Preferably, said unloading station comprises a roller plane for unloading the plates at the end of the cleaning cycle.

[0069] According to a preferred embodiment of the invention, the cleaning apparatus is equipped with a cleaning assembly comprising a tank containing a cleaning substance in the liquid state. The cleaning assembly further comprises a motorized pump capable of drawing the cleaning substance out of the tank and sending it to a primary hydraulic circuit comprising at least one dispensing nozzle. Preferably, the at least one dispensing nozzle is housed within the cleaning and suction chamber.

[0070] According to the invention, the cleaning substance circulating in the hydraulic circuit of the cleaning liquid is preferably sprayed on both surfaces of the opposite sides of the plates. The cleaning liquid is preferably sprayed through at least one pair of said dispensing nozzles, namely, at least one nozzle located above the region through which the plate passes in the cleaning and suction chamber and a second nozzle located below the region at which the plate passes in the cleaning and suction chamber.

[0071] Preferably, the cleaning and suction assembly further comprises a collection vessel for recovering the cleaning substance sprayed from the dispensing nozzles on the surfaces of the plates and precipitating downwards after possibly encountering the plates in the detergent-applying chamber of the corresponding detergent-applying station. The collection vessel is preferably located above the tank so that the detergent collected in the vessel can reach the inside of the tank by gravity, preferably through an appropriate duct.

[0072] Downstream of the motorized pump of the cleaning assembly there are provided a filter and a secondary circuit, or bypass circuit, for the return of the cleaning substance to the tank. The cleaning substance passing through the pump is filtered by the filter and sent to the primary circuit and, from there, to the dispensing nozzles and the secondary or bypass duct, and, from there, is recovered in the tank.

[0073] The primary circuit preferably comprises a multi-way manifold, with a way for each detergent dispensing nozzle, to generate the corresponding flow of cleaning substance directed to the various dispensing nozzles. The manifold will also preferably be equipped with valves that intercept the direct flow to the detergent dispensing nozzles, so that it is possible to exclude one or more of said nozzles, if necessary, e.g. depending on the size of the plates to be cleaned. Said valves can be either manual valves or automated valves and are controlled by an electronic control unit that processes the signal generated by a plate size sensor.

[0074] Thanks to the secondary or bypass circuit, the cleaning substance contained in the tank is filtered continuously and the pump can be kept running even when all nozzles are closed.

[0075] In a preferred embodiment of the invention, in the first detergent-applying chamber, the cleaning substance contained in the tank is sprayed by the nozzles onto both surfaces of the opposite sides of the transiting plates. According to the invention, the primary purpose of this detergent-applying chamber is not to wash the transiting plates, but to coat the opposite surfaces thereof with the cleaning substance.

[0076] According to an even more preferred embodiment of the invention, the first detergent-applying chamber preferably comprises at least four dispensing nozzles, namely two upper dispensing nozzles for dispensing the cleaning substance downwards against the upper side of the plates and two lower dispensing nozzles for delivering the cleaning substance upwards against the lower side of the plates.

[0077] Furthermore, preferably, these dispensing nozzles are chosen so that the cleaning liquid exiting the nozzles is transformed into tiny droplets. The cleaning substance is therefore substantially atomized when it leaves the nozzles and is sprayed diffusely over the surface, preferably over most of the surface, and even more preferably over the entire surface, of the opposite sides of the transiting plates.

[0078] The dispensing nozzles are preferably capable of generating a fan of atomized cleaning substance with opening angle of about 110° in a plane substantially perpendicular to the rectilinear direction of the plates passing through the detergent-applying chamber inside the detergent-applying station.

[0079] Preferably, the cleaning substance that does not reach the surface of the plates precipitates and thus arrives by gravity in the collection vessel and from there it arrives, still by gravity, through an appropriate duct, in the tank for the cleaning substance.

[0080] According to the invention, a first cleaning and suction chamber is provided downstream of the first detergent-applying chamber. Therefore, after a plate has passed through the first detergent-applying chamber, in which said cleaning substance has been sprayed onto the plate and preferably onto both surfaces of the plate, the plate reaches the first cleaning and suction station.

[0081] According to a preferred embodiment of the invention, in the first cleaning and suction station the surfaces of the opposite sides of the plate are hit by a steam jet delivered by corresponding steam-dispensing nozzles. In addition, the dispensed steam that invaded the cleaning and suction chamber in the corresponding station and has brushed the surfaces of the plates is sucked in, together with the substances removed from the plates, through a suction circuit equipped with suction ports communicating with the cleaning and suction chamber.

[0082] Advantageously, the cleaning and suction chamber is configured to reduce air suction from the environment outside the chamber itself and thereby ensure good suction of the substances present on the surfaces of the plates.

[0083] The steam-dispensing nozzles are connected to a steam circuit, which incorporates a multi-outlet manifold, each outlet being connected, e.g. by flexible ducts, to a respective steam-dispensing nozzle. Each outlet of the steam manifold is preferably provided with a shut-off valve, either of the manual or automated type, to disable steam delivery from one or more nozzles if necessary, depending on the degree of dirt on the plates.

[0084] The inlet of the steam manifold is connected to and receives a steam flow from a steam production machine associated with a steam production machine. The steam production machine may be permanently associated with the frame of the cleaning apparatus, or it may be mobile, e.g. wheeled. In addition, it will also be possible to provide to intercept an industrial steam distribution line already present for other purposes in the building housing the cleaning apparatus.

[0085] The suction ports opening into the cleaning and suction chamber are connected to a suction circuit, which preferably incorporates a multi-inlet manifold, each inlet being connected, e.g. by flexible ducts, to a respective suction port. Each inlet of the suction manifold can possibly be equipped with a shut-off valve, either of the manual or automated type, to disable the air intake from one or more suction ports if necessary, depending on e.g. the size of the plates passing through the cleaning and suction chamber and / or depending on the degree of vacuum to be applied in the cleaning and suction chamber.

[0086] The suction manifold comprises an outlet for the sucked-in air that communicates via a duct, e.g. a flexible duct, with a suction unit. The suction unit may comprise an extractor fan permanently associated with the frame of the cleaning apparatus or external to said apparatus and autonomous, e.g. mounted to a wheeled structure. In addition, it will also be possible to provide to intercept an industrial air suction line, already present for other purposes in the building that houses the cleaning apparatus.

[0087] According to the invention, the steam condensed on the surfaces of the plates and possibly on the other parts of the cleaning and suction chamber, together with the substances on these plates, is advantageously sucked in and conveyed into a suction tank. Depending on the needs, the content of the suction tank can be disposed of or reused, for example, after a purifying treatment.

[0088] According to a preferred embodiment of the apparatus according to the invention, as anticipated above, there are a total of four alternating detergent application stations and cleaning and suction stations. Preferably, the two detergent-applying stations are identical to each other and the two cleaning and suction stations are identical to each other so as to define a preferably substantially modular structure for said apparatus. The modularity of the apparatus will also be applicable to a larger number of stations.

[0089] At the outlet and downstream of the last cleaning and suction station with which the cleaning apparatus according to the invention is equipped there is provided a liquid removal station, preferably capable of generating at least one air blade, and even more preferably a compressed air blade.

[0090] In a preferred embodiment of the invention, the liquid removal station comprises a pair of compressed air diffusers, capable of generating a laminar-type compressed air flow, i.e. substantially air blades. The compressed air flow is preferably directed against the surfaces of the opposite sides of the transiting plates. The diffusers have an elongated shape and are arranged transversely to the rectilinear direction of feeding of the plates, one above and one under the region occupied by the transiting plate in the liquid removal station. Preferably, according to the invention, the air blades are directed along a plane substantially perpendicular to the rectilinear direction of feeding of the plates. Even more preferably, the air blades are directed along a plane inclined relative to the transiting plates and opposite the direction of feeding of the plates in the blowing chamber. Thanks to the inclined arrangement of the air blades, the liquid present on the surface of the plates is removed in a direction opposite the direction of feeding of the plates in the cleaning apparatus.

[0091] The compressed air diffusers are connected to a compressed air circuit, which incorporates a multi-outlet manifold, each outlet being connected, e.g. by flexible ducts, to a respective diffuser. Each outlet of the compressed air manifold may advantageously be provided with a shut-off valve, either of the manual or automated type, to disable, if necessary, compressed air exit from the corresponding diffuser.

[0092] The compressed air manifold comprises a compressed air inlet which communicates with a compressor unit through a duct, e.g. a flexible duct.

[0093] In addition, it will also be possible to provide to intercept an industrial compressed air line already present for other purposes in the building that houses the cleaning apparatus.

[0094] Preferably, the compressed air generated by the compressor unit, or coming from the industrial compressed air line, is filtered before being introduced into the compressed air circuit of the cleaning apparatus.

[0095] The air blades generated in the liquid removal chamber are not intended to dry the surface of the plates completely, but rather to remove the excess liquid, i.e. essentially the steam that has condensed on the surfaces of the opposite sides of the plate. As well as speeding up the subsequent drying phase, which takes place in the drying station located downstream of the liquid removal station, this operation of removing excess liquid has the main purpose of avoiding the formation of damp patches on the plate surfaces. Damp patches, if not removed before the drying phase, can give rise to halos or stains.

[0096] The drying station comprises a drying chamber equipped with heated-air diffusers, a first diffuser being located above relative to the region at which the plates pass through said drying chamber, and a second diffuser being located below the region at which the plates pass through said drying chamber. The heated-air diffusers are connected, e.g. by metal ducts, to the outlet of a corresponding electric heater. The heater receives the incoming air at room temperature, through a duct, from a blower in common with the heaters. A hot air distribution manifold is provided between the blower and the heaters, to ensure that an evenly distributed air flow enters the two heaters.

[0097] According to the invention, for example, two 6kW heaters can be used, each capable of generating a flow of heated air at adjustable temperature, which can reach a maximum temperature of around 300°C on the surface of the plate, so that the last remaining traces of moisture are evaporated almost instantaneously.

[0098] The rollers provided in the drying chamber to allow feeding of the plates are preferably shielded by screens made of metal or a high-temperature resistant material. These screens are configured to allow free passage of air through two adjacent rollers and simultaneously shield the surfaces of the rollers from the high-temperature air emitted by the diffusers, which air could damage the surfaces of the rollers. The hot air emitted by the diffusers therefore substantially brushes only the surface of the screens provided for shielding the rollers. An excessive rise in the temperature of the rollers could in fact lead to roller damage.

[0099] The plate unloading station arranged downstream of the drying station substantially comprises a roller conveyor for transferring out of the drying station and towards the outside of the cleaning apparatus the plates that have undergone a drying cycle. At the unloading station there is preferably provided a plate-presence sensor, capable of generating a signal indicative of the presence of a plate in the unloading station. The signal generated by the plate-presence sensor is processed by an electronic unit, which controls the running and stopping of the apparatus. In this way, the plate-presence sensor substantially acts as an overflow and causes the apparatus to stop if the plates are not removed from the unloading station in time, so as to prevent damage to the plates themselves and to the parts of the cleaning apparatus.

[0100] A mechanical block that stops the plates in the unloading station, preventing them from falling off the roller conveyor, can also be provided to allow tests to be carried out on the apparatus that do not involve in-line use of the plates.Brief Description of the Figures

[0101] A preferred embodiment of the invention is described below with reference to the annexed figures, in which: Fig. 1 is a front plan view of the cleaning apparatus; Fig. 2 is an enlarged front plan view of the apparatus of Fig.1; Fig. 3 is a view of the chamber for applying a detergent mixture; Fig. 4 is a lateral plan view of the apparatus of Fig.1; Fig. 5 is a view of the cleaning and suction chamber.

[0102] In all figures, the same reference numerals have been used to distinguish identical or functionally equivalent components.Description of Some Preferred Embodiments of the Invention

[0103] Referring to Fig. 1, this illustrates a plate cleaning apparatus 11 according to a preferred embodiment of the invention.

[0104] The shown apparatus 11 comprises a detergent-applying station 13, a steam cleaning station 15, a suction station 17, a drying station 19 and movement members 21 defining a transport line 23 for transporting industrial plates 100 through said stations.

[0105] The shown apparatus 11 is equipped with movement members 21 comprising a plurality of belt feed assemblies 25 arranged below the transport line 23 and a plurality of roller compression assemblies 27 arranged above the transport line 23.

[0106] The belt feed assemblies 25 and roller compression assemblies 27 cooperate with each other to cause rectilinear advance of the plates 100 through said detergent-applying stations 13, steam cleaning stations 15, suction stations 17 and drying stations 19, along a feeding plane 29.

[0107] In the shown embodiment of the apparatus 11, the steam cleaning station 15 and the suction station 17 comprise a cleaning and suction chamber 31 in common and said stations 15, 17 define together a corresponding integrated cleaning and suction station 33. Advantageously, therefore, the delivery of cleaning steam and the suction of the delivered steam that has brushed the surfaces of the plates 100 passing through said cleaning and suction station 33 take place simultaneously in the cleaning and suction chamber 31 of the integrated station 33.

[0108] Still referring to the embodiment shown in Fig. 1, the apparatus 11 comprises at least one pair of detergent-applying stations 13 and at least one pair of cleaning and suction stations 33, alternating with each other, the detergent-applying stations 13 being arranged upstream of the cleaning and suctions stations 31.

[0109] As can best be appreciated from Fig. 2, the belt feed assemblies 25 comprise a motor-driven conveyor belt 35 equipped with a pair of upper rollers 37a, 37b, one 37b of which is a motor-driven roller and the other one 37a is an idle roller, and a lower idle roller 37c. A belt 39 is provided around said three rollers. The rollers 37a, 37b, 37c of said feed assembly 25 are arranged horizontally with their respective rotation axes mutually parallel and perpendicular to the rectilinear direction of feeding of the plates 100 on the feeding plane 29. In this way, a substantially horizontal portion 39a for transporting the plates 100 along the feeding plane 29 passing through the stations of the apparatus 11 is defined on the belt 39. The belt feed assemblies 25 are configured in such a way that the rotation axes of the rollers 37a, 37b, 37c intersect an imaginary plane located perpendicularly to said axes, substantially at the vertices of an equilateral triangle.

[0110] The roller compression assembly 27 comprises idle rollers 41 arranged with their respective rotation axes mutually horizontal and mutually parallel and perpendicular to the rectilinear direction of feeding of the plates 100 on the feeding plane 29. The idle rollers 41 of the compression assembly 27 are susceptible to take a proximal configuration relative to the belt feed assembly 25 cooperating with said compression assembly 27 and a distal configuration relative to said belt feed assembly 25.

[0111] The roller compression assembly 27 and the distance between the axes of said rollers 41 in a direction perpendicular to said axes is chosen in such a way that the rollers 41 of the compression assembly 27 perform an essentially simultaneous compression on the upper surface of a plate 100 arranged horizontally between said assemblies 25, 27, at the substantially horizontal portion 39a defined on the belt 39 of the belt feed assembly 25, between the idle roller 37a and the motor-driven roller 37b.

[0112] The illustrated apparatus 11 comprises, in the direction of feeding of the plates 100 through the stations of the apparatus 11, indicated with arrow "F", a first and a last roller compression assembly 27 equipped with a pneumatic actuator 43 to cause switching from a configuration to the other one and vice versa. Said first and last roller compression assemblies 27 cooperate with a corresponding underlying belt feed assembly 25, near the inlet and the outlet of the belt feeding plane 29 in the plate cleaning apparatus 11, respectively.

[0113] Still referring to the illustrated apparatus 11, between said first and said last belt feed assemblies 25, which can be defined as head and tail belt feed assemblies, respectively, there are provided four belt feed assemblies 25, which can be defined as intermediate belt feed assemblies. Said intermediate belt feed assemblies 25 cooperate with corresponding intermediate roller compression assemblies 27. The rollers 41 associated with the intermediate compression rollers 27 can take either a proximal or a distal configuration relative to the underlying belt 39 of the corresponding belt feed assembly 25. In the intermediate roller compression assemblies 27, the proximal configuration is maintained by means of elastic means 45, in particular coil springs, which oppose, with their own elastic resistance, the switching from said proximal to said distal configuration.

[0114] Still referring to Fig. 2, a liquid removal station 47 is provided downstream of the detergent-applying station 13 and the cleaning and suction stations 33. Said liquid removal station 47 comprises a liquid removal chamber 49 housing a pair of compressed air diffusers 51. Advantageously, the compressed air diffusers 51 are capable of generating a laminar-type compressed air flow, i.e. substantially an air blade. Also, the air blade produced by the laminar-type compressed air diffusers 51 is preferably directed against the surfaces of the opposite sides of the plates 100 passing through said liquid removal station 47.

[0115] The diffusers 51 have an elongated shape and are arranged one above and one under the region occupied by the plate 100 passing through the liquid removal station 47. The air blades are directed along a plane substantially inclined relative to the transiting plates 100 and opposite the direction of feeding of the plates, indicated by arrow "F", in the liquid removal chamber. Thanks to the inclined arrangement of the air blades, the liquid present on the surface of the plates is removed in a direction opposite the direction of feeding of the plates in the cleaning apparatus 11.

[0116] The compressed air diffusers 51 are connected to a compressed air circuit, which incorporates a multi-outlet manifold, each outlet being connected to a respective diffuser by means of flexible ducts. The compressed air manifold comprises a compressed air inlet communicating with an industrial compressed air line through a flexible duct equipped with a filter.

[0117] The air blades that are generated in the liquid removal chamber 49 are not intended to dry the surface of the plates 100 completely, but rather to remove the excess liquid, i.e. essentially the steam that has condensed on the surfaces of the opposite sides of the plate 100. As well as speeding up the subsequent drying phase, which takes place in the drying station 19 located downstream of the liquid removal station 47, this excess liquid removal operation taking place in the drying station 19 arranged downstream of the liquid removal station 47 has the main purpose of avoiding the formation of damp patches on the plate surfaces. Damp patches, in fact, if not removed before the drying phase, can give rise to halos or stains.

[0118] Downstream of the liquid removal station 47, where provided, there is also advantageously provided a drying station 19 comprising a drying chamber 55. The drying chamber 55 is provided with a pair of heated-air diffusers 57, a first diffuser 57 being located above the region at which the plates 100 pass through said drying chamber 55 and a second diffuser 57 being located below the region at which the plates pass through said drying chamber 55.

[0119] According to the illustrated preferred embodiment of the invention, a plate 100 to be subjected to a cleaning cycle in the apparatus 11 according to the invention undergoes a treatment involving, in order, mainly a step of feeding the plate to the cleaning apparatus 11, a step of applying some detergent onto the plate, a step of steam-cleaning the plate, a step of sucking dirt off the plate, a step of removing the liquid from the plate, a step of drying the plate and a step of unloading the plate. In this shown embodiment, the step of sucking dirt off the plate is also advantageously performed substantially simultaneously with the steam-cleaning step.

[0120] Referring to Fig. 1, two heated-air diffusers 57 are connected each to the outlet of a corresponding electric heater 58 by means of metal ducts. Each heater 58 receives incoming air at room temperature, through a duct, from a blower 60 in common with the two heaters 58. A hot air distribution manifold is provided between the blower 60 and the heaters 58, to ensure that an evenly distributed air flow enters the two heaters 58.

[0121] In the shown embodiment, two 6kW heaters are used, each capable of generating a flow of heated air at adjustable temperature, which can reach a maximum temperature of around 300°C on the surface of the plate, so that the last remaining traces of moisture are evaporated almost instantaneously.

[0122] Downstream of the drying station 19 there is provided the plate unloading station 79 comprising a roller conveyor equipped with rollers 80 for transferring out of the drying station 19 and towards the outside of the cleaning apparatus 11 the plates, which have undergone a drying cycle. At the unloading station 19 there is preferably provided a plate-presence sensor, capable of generating a signal indicative of the presence of a plate in the unloading station. The signal generated by the plate-presence sensor is processed by the electronic unit of the apparatus 11, which electronic unit controls the running and stopping of the apparatus. In this way, the plate-presence sensor substantially acts as an overflow and causes the apparatus to stop if the plates are not removed from the unloading station in time, so as to prevent damage to the plates themselves and to the parts of the cleaning apparatus.

[0123] In the illustrated embodiment, the drying station 19 extends over part of the rollers 80 of the roller conveyor of the unloading station 79 provided for allowing feeding of the plates. The rollers 80 affected by the drying station 19 are shielded by screens 82 made of metal or a high-temperature resistant material. These screens 82 are configured to allow free passage of air through two adjacent rollers 80 and simultaneously shield the surfaces of the rollers from the high-temperature air emitted by the diffusers 57, which air could damage the surfaces of the rollers 80. The hot air emitted by the diffusers 57 therefore substantially brushes only the surface of the screens 82 provided for protecting said rollers.

[0124] Referring again to Fig. 1, the shown apparatus comprises a loading station 61 preceding all other plate treatment stations. The loading station 61 includes a loading unit 63 situated at the entrance of the apparatus. In this preferred embodiment of the invention, the function of the loading unit is substantially to transfer a plate from the actual loading area, i.e. from the area where the plate is loaded onto the loading unit, to a first treatment station of the cleaning apparatus. In the illustrated embodiment, said first treatment station coincides with the first detergent-applying station 13. The loading unit 63 therefore essentially defines, in this preferred embodiment of the invention, the initial portion of the feeding plane 29 and therefore the starting zone for the movement of the plates 100 through the stations of the apparatus.

[0125] A lateral guide 65 is provided at the loading unit 63, to ensure the correct alignment of the plates 100 on the plane defined on the loading unit 63. The guide 65 is preferably adjustable at least transversely, to allow the loading unit 63 to be adapted to plates 100 of different width. The adjustment of the guide 65 takes place manually, by acting onto special screws 65a that fix the guide to the frame 67 of the apparatus.

[0126] The loading unit 63 comprises a motor-driven conveyor belt equipped with a pair of rollers 69a, 69b, one 69b of which is a motor-driven roller, and the other one 69a is an idle roller, and a belt 71 made of a silicone plastic material. In addition, the idle roller 69a is actuated by the movement imparted by the belt 71, which is in turn entrained by the motor-driven roller 69b.

[0127] The rollers 69a, 69b have mutually horizontal and mutually parallel axes perpendicular to the rectilinear direction of feeding of the plates on the feeding plane 29, indicated by arrow F, of the cleaning apparatus. In the illustrated embodiment, the motor-driven roller 69b is located proximal to the first treatment station of the cleaning apparatus, i.e. the first detergent-applying station 13, and the idle roller 69a is located in a distal position relative to said first station. In addition, still according to this illustrated embodiment of the invention, the distance between the rotation axis of the idle roller 69a and the rotation axis of the motor-driven roller 69b is adjustable to place the belt 71 in the correct tensioning state. Idle counter-rollers 73 are provided below the belt 71, in contact with the surface of the side of the belt 71 opposite the belt side on which the plates 100 lie. The idle counter-rollers mainly have the purpose of keeping the belt flat, preventing it from bending under the weight of the plates. The number of the idle counter-rollers will be proportional to the length of the loading unit 63 and the rigidity of the belt 71.

[0128] A plate 100 loaded on the loading unit 63 arranged at the entrance of the cleaning apparatus 11 is then transferred from said loading unit 63 towards the first detergent-applying station 13.

[0129] Referring to Fig. 3, the detergent-applying station 13 comprises a detergent-applying chamber 75 in which the detergent is applied to the transiting plate 100, preferably to both surfaces of the opposite sides of said plate 100.

[0130] While transiting from the loading unit 63, where provided, to a first detergent-applying chamber 13, the plate 100 encounters a first belt feed assembly 25 defining a portion of the feeding plane 29 located downstream of the portion defined by the loading plane of the loading unit 63 in the direction of feeding of the plates 100, indicated by arrow F, in the apparatus 11. The belt feed assembly 25 cooperates with the first roller compression assembly 27 actuated by an actuator 43.

[0131] At the loading unit 63 there is provided a sensor for measuring the thickness of the transiting plates 100 to be cleaned. The signal generated by said sensor is processed by an electronic control unit, which controls driving of the actuator 43 depending on the thickness of the plates 100. The length of the stroke of the actuator 43 and the relative positions taken by the idle rollers 41 with respect to the surface of the belt 39 are therefore determined by the electronic control unit, which has processed the signal coming from the at least one sensor for sensing the thickness of the plates 100 arriving at the first belt feed assembly 25.

[0132] The pressure exerted by the idle rollers 41 on the transiting plate 100 and counteracted by the belt 39 of the first belt feed assembly 25, generates, between the plate 100 and said belt 39, sufficient friction to ensure straight and jerk-free feeding, with essentially constant speed, of the plates along the apparatus 11.

[0133] The starting of the actuator 43 is also driven by the signal processed by an electronic control unit, which receives a signal coming from a sensor 77 sensing the presence of the plate 100 in the position appropriate for undergoing compression. The presence sensor 77 is provided, for example, at the exit from the first belt feed assembly 25, so as to intercept the front edge of the plate 100 advancing along the cleaning apparatus in the direction indicated by arrow F.

[0134] Downstream of the drying chamber 55 there is provided an unloading station 79 for unloading the plates 100 that have undergone the cleaning cycle. The unloading station 79 comprises a plane with idle rollers 77 for unloading the plates at the end of the cleaning cycle.

[0135] Referring also to Fig. 4, according to the illustrated embodiment of the invention, the cleaning apparatus 11 is equipped with a detergent unit 81 comprising a tank 83 containing a cleaning substance in the liquid state. The detergent unit 81 further comprises a motorized pump 84 capable of drawing the cleaning substance out of the tank 83 and sending it to a primary hydraulic circuit comprising dispensing nozzles 85, housed in the detergent-applying chamber 75, for the cleaning substance.

[0136] The cleaning substance circulating through the hydraulic circuit for the cleaning liquid is sprayed on both surfaces of the opposite sides of the plates 100. The cleaning liquid is sprayed through two pairs of dispensing nozzles 85, namely at least one pair of nozzles 85 located above the region through which the plate 100 passes through detergent-applying chamber 75 and at least one pair of nozzles 85 located below the region at which the plate passes through the detergent-applying chamber 75.

[0137] The apparatus 11 further comprises a collection vessel 87 for recovering the cleaning substance sprayed by the dispensing nozzles 85 onto the surfaces of the plates 100 and precipitating downwards after possibly brushing the plates 100 in the detergent-applying chamber 75 of the corresponding detergent-applying station 13. The collection vessel 87 is preferably located above the tank 83 so that the cleaning substance collected in the collection vessel 87 can reach the inside of the tank 83 by gravity, preferably through an appropriate duct.

[0138] Downstream of the motorized pump 84 of the detergent unit 81 there are provided a filter 86 and a secondary circuit, or bypass circuit, for the return of the cleaning substance to the tank 83. The cleaning substance passing through the pump is filtered by the filter and sent to the primary circuit and, from there, to the dispensing nozzles 85 and the secondary or bypass duct, and, from there, is recovered in the tank 83.

[0139] The primary circuit comprises a multi-way manifold, one for each detergent-dispensing nozzle 85, to generate a corresponding flow of cleaning substance directed to the various dispensing nozzles 85. The manifold is provided with valves that shut off the direct flow to the detergent-dispensing nozzles 85, whereby it is possible to shut off, if needed, for example depending on the size to the plates to be cleaned, one or more of said dispensing nozzles 85. In the illustrated embodiment, said valves are of the manual type. Thanks to the secondary or bypass circuit, the cleaning substance contained in the tank 83 is filtered continuously and the pump can be kept running even when all nozzles 85 are shut off by means of said valves.

[0140] In the detergent-applying chamber 75 of the first detergent-applying station 13, the cleaning substance contained in the tank 83 is sprayed by the dispensing nozzles 85 onto both surfaces of the opposite sides of the transiting plates 100. According to the invention, the primary purpose of this detergent-applying chamber 75 is not to wash the transiting plates, but to coat the opposite surfaces thereof with the cleaning substance.

[0141] As anticipated above, the first detergent-applying chamber 75 comprises four dispensing nozzles 85, namely two upper dispensing nozzles for dispensing the cleaning substance downwards against the upper side of the plates and two lower dispensing nozzles for delivering the cleaning substance upwards against the lower side of the plates 100. Furthermore, these dispensing nozzles 85 are chosen so that the cleaning liquid exiting the nozzles is transformed into tiny droplets. The cleaning substance is therefore substantially atomized when it leaves the dispensing nozzles 85 and is sprayed diffusely over the surface, preferably over most of the surface, and even more preferably over the entire surface, of the opposite sides of the transiting plates 100.

[0142] The dispensing nozzles of the illustrated embodiment are preferably capable of generating a fan of atomized cleaning substance with opening angle of about 110° in a plane substantially perpendicular to the rectilinear direction of the plates 100 passing through the detergent-applying chamber 75 inside the detergent-applying station 13.

[0143] The cleaning substance that does not reach the surface of the plates 100 precipitates and thus arrives by gravity in the collection vessel 87 and from there it arrives, still by gravity, through an appropriate duct, in the tank 83 for the cleaning substance.

[0144] Referring to Fig. 5, in the cleaning and suction station 33 the surfaces of the opposite sides of the plate 100 are hit by a steam jet delivered by corresponding steam-dispensing nozzles 89. In addition, the dispensed steam that has invaded the cleaning and suction chamber 31 in the corresponding station 33 and has brushed the surfaces of the plates is sucked in, together with the substances removed from the plates, through a suction circuit equipped with suction ports 91 communicating with the cleaning and suction chamber.

[0145] Advantageously, the cleaning and suction chamber 31 is configured to reduce air suction from the environment outside the chamber itself and thereby ensure good suction of the substances present on the surfaces of the plates 100.

[0146] The steam-dispensing nozzles 89 are connected to a steam circuit, which incorporates a multi-outlet manifold, each outlet being connected, e.g. by flexible ducts, to a respective steam-dispensing nozzle 89. Each outlet of the steam manifold is provided with a shut-off valve of the manual type, to disable steam delivery from one or more nozzles 89 if necessary, depending on the degree of dirt on the plates.

[0147] The inlet of the steam manifold is connected to and receives a steam flow from a steam unit associated with a steam production machine. The steam production machine may be permanently associated with the frame of the cleaning apparatus, or it may be mobile, e.g. wheeled. In addition, it will also be possible to provide to intercept an industrial steam distribution line already present for other purposes in the building housing the cleaning apparatus.

[0148] The suction ports 91 opening into the cleaning and suction chamber are connected to a suction circuit, which preferably incorporates a multi-inlet manifold, each inlet being connected, e.g. by flexible ducts, to a respective suction port 91.

[0149] The suction manifold comprises an outlet for the sucked-in air that communicates via a duct, e.g. a flexible duct, with a suction unit. The suction unit comprises an extractor fan external to said apparatus and autonomous, e.g. mounted to a wheeled structure.

[0150] According to the invention, the steam condensed on the surfaces of the plates 100 and possibly on the other parts of the cleaning and suction chamber 31, together with the substances on said plates 100, is advantageously sucked in and conveyed into a suction tank. Depending on the needs, the content of the suction tank can be disposed of or reused, for example, after a purifying treatment.

[0151] In the illustrated apparatus made according to a preferred embodiment of the invention, the two detergent-applying stations 13 and the two cleaning and suction stations 33 are identical to each other and the two cleaning and suction stations are identical to each other so as to define a preferably substantially modular structure for said cleaning apparatus 11.

[0152] It is apparent from the above description that the apparatus according to the invention achieves the intended purposes and that the cleaning efficiency is remarkably increased by repeatedly subjecting the entire surface of each plate to the action of the cleaning fluid, without substantially increasing the time taken by the plate to pass through the cleaning chamber and without requiring major modifications to the structure or interfering with the usual operating parameters of the apparatus.

[0153] Obvious changes or variations are possible to the above description, in the dimensions, shapes, materials, components, circuit elements, connections and contacts, as well as in the details of the circuitry and construction illustrated and of the method of operation as specified in the following claims.

Claims

1. Steam-cleaning apparatus (11) for cleaning industrial plates comprising: - a detergent-applying station (13); - a steam-cleaning station (15); - a suction station (17); - a drying station (19); - movement members (21) defining a transport line (23) for transporting industrial plates (100) through said stations (13, 15, 17, 19); wherein the movement members (21) comprise at least one belt feed assembly (25), located below relative to the transport line (23), and at least one roller compression assembly (27), located above relative to the transport line (23), said belt feed assembly (25) and said roller compression assembly (27) cooperating with each other to cause rectilinear feeding of the plates (100) through said stations (13, 15, 17, 19) along a feeding plane (29), characterized in that said belt feed assembly (25) comprises a motor-driven conveyor belt (35) equipped with a pair of upper rollers (37a,37b), one (37b) of which is a motor-driven roller and the other one (37a) is an idle roller, and a lower idle roller (37c), wherein a belt (39) is provided around said rollers (37a, 37b, 37c), the rollers (37a, 37b, 37c) of said feed assembly (25) being arranged horizontally with their respective rotation axes mutually parallel and perpendicular to the rectilinear direction of feeding of the plates (100) on the feeding plane (29) so as to define a substantially horizontal portion of said belt (39) for transporting the plates (100) along the feeding plane (29).

2. Apparatus according to claim 1, wherein said steam-cleaning station (15) and said suction station (17) comprise a cleaning and suction chamber (31) in common, and said stations (15,17) define, in combination, a corresponding cleaning and suction integrated station (33).

3. Apparatus according to claim 2, wherein said apparatus comprises at least one pair of detergent-applying stations (13) and at least one pair of cleaning and suction stations (33), said stations (13, 33) being alternated with each other, and the detergent-applying stations (13) being arranged upstream of the cleaning and suction stations (33).

4. Apparatus according to claim 1 or 2 or 3, wherein the rotation axes of the rollers (37a, 37b, 37c) of said feed assembly (25) intersect an imaginary plane located perpendicularly to said axes, substantially at the vertices of an equilateral triangle.

5. Apparatus according to claim 1 or 4, wherein the roller compression assembly (27) comprises idle rollers (41) arranged with their respective rotation axes mutually horizontal and mutually parallel and perpendicular to the rectilinear direction of feeding of the plates (100) on the feeding plane (29), said idle rollers (41) of the compression assembly (27) being susceptible to take a proximal configuration relative to the belt feed assembly (25) cooperating with said compression assembly (27) and a distal configuration relative to said belt feed assembly (25), the switching from said proximal configuration to said distal configuration and vice versa being obtained by means of an actuator (43), for example, of the pneumatic, hydraulic or electromechanical type.

6. Apparatus according to claim 5, wherein the roller compression assembly (27) and the distance between the axes of said rollers (41) in a direction perpendicular to said axes are chosen so that the rollers (41) of the compression assembly (27) carry out a substantially simultaneous compression onto the upper surface of a plate (100) arranged horizontally between said assemblies (25, 27), at a substantially horizontal portion (39a) defined on the belt (39) of the feed assembly (25), between the idle roller (37a) and the motor-driven roller (37b).

7. Apparatus according to claim 6, wherein the apparatus comprises, in the direction of feeding of the plates (100) through the stations of the apparatus (11), a first and a last roller compression assembly (27) equipped with a pneumatic actuator (43) to cause switching from a configuration to the other one and vice versa.

8. Apparatus according to claim 7, wherein said first and last roller compression assemblies (27) cooperate with a corresponding first and last underlying belt feed assembly (25), near the inlet and the outlet of the belt feeding plane (29) in the plate cleaning apparatus (11), respectively.

9. Apparatus according to claim 8, wherein four intermediate belt feed assemblies (25) are provided between said first and last belt feed assemblies (25), said intermediate belt feed assemblies (25) cooperating with corresponding intermediate roller compression assemblies (27).

10. Apparatus according to claim 9, wherein the rollers (41) associated with the intermediate compression rollers (27) can take a proximal or distal configuration relative to the underlying belt (39) of the corresponding belt feed assembly (25).

11. Apparatus according to claim 10, wherein in the intermediate roller compression assemblies (27) the proximal configuration is maintained by means of elastic means (45), for example coil springs, which oppose, with their own elastic resistance, the switching from said proximal to said distal configuration.

12. Apparatus according to claim 1 or 4 or 5, wherein said roller compression assembly (27) comprises idle rollers (41) arranged with their respective rotation axes mutually horizontal and mutually parallel and perpendicular to the rectilinear direction of feeding of the plates (100) on the feeding plane (29), said rollers (41) of the compression assembly (27) being susceptible to take a proximal configuration relative to the belt feed assembly (25) cooperating with said compression assembly (27) and a distal configuration relative to said belt feed assembly (25), said compression assembly (27) being supported by elastic means (45) capable of causing switching of said rollers (41) from said distal configuration to said proximal configuration and to oppose, with their elastic resistance, the switching from said proximal configuration to said distal configuration.

13. Apparatus according to claim 11 and 12, wherein said movement members (21) comprise a plurality of belt feed assemblies (25) and a corresponding plurality of compression assemblies (27), the switching from said proximal configuration to said distal configuration and vice versa being obtained by means of an actuator (43) in the first and last of said compression assemblies (27), and the switching from said distal configuration to said proximal configuration being obtained by means of elastic means (45) in the intermediate compression assemblies (27).

14. Apparatus according to claim 3, wherein downstream of the detergent-applying stations (13) and downstream of the cleaning and suction stations (33) there is provided a liquid removal station (47) comprising a liquid removal chamber (49) housing a pair or compressed-air diffusers (51), capable of generating a laminar-type compressed air flow, i.e., substantially an air blade directed against the surfaces of the opposite sides of the plates (100) that are passing through said liquid removal station (47).

15. Apparatus according to claim 3 or 14, wherein downstream of the liquid removal station (47) there is provided a drying station (19) comprising a drying chamber (55) equipped with heated-air diffusers (57), a first diffuser being located above relative to the region at which the plates (100) pass through said drying chamber (55), and a second diffuser being located below relative to the region at which the plates (100) pass through said drying chamber (55).

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