EP3742096A1

EP3742096A1 - Drying oven and drying method

Info

Publication number: EP3742096A1
Application number: EP20175967.7A
Authority: EP
Inventors: Mario Ceccuzzi; Simone CECCUZZI
Original assignee: Makor Srl
Current assignee: Makor Srl
Priority date: 2019-05-24
Filing date: 2020-05-22
Publication date: 2020-11-25
Anticipated expiration: 2040-05-22
Also published as: EP3742096B1; EP3742096C0; IT201900007224A1

Abstract

Described is an oven (1) for drying painted elements, comprising a plurality of cages (2) or mats containing the painted elements, an infeed station (3a) for the painted elements and an outfeed station (3b) for the painted elements. The oven (1) also comprises at least one column (5) of housings shaped in such a way as to house respective cages (2) or mats. The housings are associated with respective air outlets configured to define zones at a different speed, temperature and/or humidity inside the drying oven (1). The oven (1) comprises a movement system (6), operatively associated with the column (5) of housings, equipped with movement means configured to transport each cage (2) or mat along a drying path wherein at least one housing defines a drying station wherein a respective cage (2) or mat stops for a preset period of time in a zone at a specific air speed, temperature and/or humidity.

Description

This invention relates to an oven for drying painted elements.
Moreover, the invention relates to a drying method for painted elements.
The term "painted elements" is used to denote elements such as, for example, doors, sashes and panels of different painted sizes with products of any type.
The elements are usually painted manually or by special robots and they are then moved into the ovens where the paint is dried.
There are prior art ovens and methods for drying the paint for these elements. In particular, the ovens and methods comprise containing the elements in suitable drying chambers. These drying chambers have air flows at a constant temperature and the elements are kept there for different times as a function of the paints applied on them.
Disadvantageously, this solution enters into conflict with different types of paints which, in order to dry correctly on the surface of the element without forming lumps or burns, must remain in the oven for different times.
Disadvantageously, this solution requires the ovens to be prepared to operate differently for each type of paint applied to the element, resulting in lengthy set-up times or the formation of bottlenecks in the production line or, for example, results which do not satisfy the necessary quality requirements of the end product.
The technical purpose of the invention is therefore to provide an oven and a drying method which are able to overcome the drawbacks of the prior art.
The aim of the invention is therefore to provide an oven and a drying method which allow the drying of painted elements with different paints, thus meeting the necessary quality requirements required by the end product.
A further aim of the invention is to provide an oven and a drying method which enable the formation of bottlenecks along the production line to be avoided and which allow the times for setting up the oven to be reduced.
The technical purpose indicated and the aims specified are substantially achieved by an oven and a drying method comprising the technical features described in one or more of the appended claims. The dependent claims correspond to possible embodiments of the invention.
In particular, the technical purpose indicated and the aims specified are substantially achieved by a drying oven for painted elements comprising a plurality of cages or mats containing the painted elements, an infeed station for the painted elements and an outfeed station for the painted elements. The oven also comprises at least one column of housings shaped in such a way as to house respective cages or mats. The housings are associated with respective air outlets configured to define zones at different temperature and/or humidity inside the drying oven. The oven also comprises a movement system, operatively associated with the column of housings, equipped with movement means configured for transporting each cage or mat along a drying path. The drying path is defined by the infeed station, by at least one respective housing of the column and by the outfeed station. The at least one housing of the drying path defines a drying station wherein a respective cage or mat stops for a preset period of time in a zone at a specific air speed, temperature and/or humidity.
Preferably, the infeed station and the outfeed station can coincide.
Advantageously, the zones at different air speeds and/or temperature and/or humidity of the various housings allow the drying of different elements painted with different paints. The movement means are configured for transporting each cage or mat, containing a specific painted element, in a specific housing having a specific air speed and/or temperature and/or humidity and picking it from the above-mentioned housing after a preset period of time in such a way as to effectively dry the paint of the element.
Preferably, the movement means are configured to transport each cage or mat to one or more further housings in such a way as to stop a specific cage in further zones at a specific air speed and/or temperature and/or humidity.
Moreover, the technical purpose indicated and the aims specified are substantially achieved by a method for drying painted elements performed by a drying oven described above. The method comprising the successive steps of preparing a plurality of cages or mats, preparing a plurality of painted elements in respective cages or on respective mats and defining, in the housing column, zones at different air speeds, temperatures and/or humidity using respective air outlets of the oven air as a function of the paint with which the elements are painted. The method also comprises inserting in sequence the cages or mats in the infeed station of the drying oven and moving the cages or mats along a drying path defined by the infeed station, by at least one respective column housing and by the outfeed station. In particular, the movement step comprises transporting a cage or mat from the infeed station to the at least one respective column housing corresponding to a zone at a specific air speed, temperature and/or humidity, stopping the cage in the zone at a specific air speed, temperature and/or humidity for a preset period of time and transporting the cage or mat from the housing to the outfeed station. Lastly, the method comprises extracting the cages or mats from the outfeed station.
Advantageously, the method comprises transporting each cage or mat to one or more column housings defining a zone at specific air speed and/or temperature and/or humidity suitable for effectively drying a specific paint with which the elements have been painted.
Further features and advantages of the invention are more apparent in the non-limiting description which follows of a non-exclusive embodiment of a drying oven and a drying method.
The description is set out below with reference to the accompanying drawings which are provided solely for purposes of illustration without restricting the scope of the invention and in which:

Figures 1A-1F are schematic representations of successive steps of the method according to the invention;
Figures 2A-2C are schematic representations of components of the oven according to the invention.

With reference to the accompanying drawings, the numeral 1 denotes in its entirety a drying oven for painted elements which, for simplicity of description, will hereafter be referred to as the oven 1.
The term "painted elements of any shape and size" (such as elements having at least two main dimensions with respect to a third), for example, doors, sashes and panels of different dimensions painted with products of any type, for example polyurethane, water-based, UV, WB and two-component UV. In other words, the term "painted elements" refers to any elements which are painted with products of any type.
The painted elements are usually painted manually or by special robots and they are then moved into the ovens where the paint is dried.
Preferably, the elements may have a length of up to 3500 mm. Alternatively, the elements may have a length of up to 5400 mm. The above-mentioned lengths are only examples; other lengths of the elements are possible.
Preferably, the elements may have a width of up to 1300 mm. Alternatively, the elements may have a width of up to 1600 mm, 2000 or another measurement. The above-mentioned widths are only examples; other widths of the elements are possible.
Preferably, the elements can have a height of up to 90 mm. Alternatively, the elements may have a height of up to 300 mm or greater.
The above-mentioned heights are only examples; other heights of the elements are possible.
The oven 1 comprises a plurality of cages 2 containing the painted elements. Alternatively, the oven 1 comprises a plurality of mats on which to rest the painted elements.
Each cage 2 or mat comprises a main body defining a containment space for a respective element. The main body comprises at least two side walls, configured to retain the element, and an upper wall defining an element for protection of the element against dust. In other words, the upper wall prevents dust from being deposited on the fresh paint of the upper surface of the element.
Preferably, the cages 2 or the mats have dimensions greater than those of the elements.
For example, for an element having a length of 3500 mm, the cage 2 will have a length of 3600 mm. Alternatively, for an element having a length of 5400 mm, the cage 2 will have a length of 5500 mm.
Preferably, the oven 1 has a number of cages 2 or mats variable on the basis of the dimensions/loading capacity of the oven 1. For example, the oven 1 may comprise twenty cages 2 or mats. Alternatively, the oven may comprise forty or more cages 2 or mats.
The oven 1 comprises a main body 3 in which to insert the painted elements and from which to extract them once the elements contained inside them have dried.
In particular, the oven 1 comprises an infeed station 3a for the painted elements and an outfeed station 3b for the painted elements.
Preferably, the infeed station 3a and the outfeed station 3b are located on the same side of the main body 3 of the oven 1, as shown by way of example in the accompanying drawings.
Alternatively, the infeed station 3a and the outfeed station 3b are located on opposite sides of the main body 3 of the oven 1.
Alternatively, the infeed station 3a and the outfeed station 3b are located on adjacent sides of the main body 3 of the oven 1.
The oven 1 may also comprise a loading roller 4a configured for introducing the cages 2 in the infeed station 3a and an unloading roller 4b configured for extracting the cages 2 from the outfeed station 3b. In other words, the loading roller 4a and the unloading roller 4b are respectively configured for introducing and extracting the cages 2 from the oven 1.
In the embodiment shown in the accompanying drawings, the loading roller 4a and the unloading roller 4b are two separate rollers.
Alternatively, if the infeed station 3a and the outfeed station 3b are located on opposite sides of the main body 3 of the oven 1, the loading roller 4a and the unloading roller 4b mean the portions of a same roller located, respectively, in the infeed station 3a and in the outfeed station 3b.
The loading roller 4a and the unloading roller 4b are linked with loading and unloading accelerators/decelerators. In other words, the oven 1 is linked with the loading and unloading accelerators/decelerators in such a way as to achieve feed speeds which range, for example, from 10 to 50 m/min. Preferably, in order to achieve these feed speeds, the oven 1 is also equipped with an inverter.
In an embodiment not illustrated, the cages 2 or mats can be introduced and extracted manually from the oven 1, for example using suitable slides. The embodiments described above are only some of the embodiments designed to allow the insertion and extraction of the cages 2 or mats from the oven 1. Other embodiments may comprise, for example, conveyor belts or robotic arms designed for the insertion and extraction of the cages 2 or mats. In other words, it is possible to use automatic means for extraction and storage of the cages 2 or mats.
The oven 1 also comprises at least one column 5 of housings shaped in such a way as to house respective cages 2 or mats. The housings may be shaped in such a way as to house cages 2 or mats with "standard" dimensions and/or cages 2 mats with larger dimensions.
For example, the term "standard" means those cages 2 shaped to contain elements with a height of up to 90 mm. The term "larger dimensions" means, for example, those cages 2 shaped to contain elements with a height of up to 300 mm.
Preferably, a housing shaped in such a way as to house larger cages 2 or mats is simply a set of housings shaped in such a way as to house cages 2 or mats with "standard" dimensions. In other words, the housings define a series of slots which can be used to house cages 2 of different dimensions.
Preferably, the housing column 5 is configured before using the oven 1 in order to select the zones which must house the cages 2 of different sizes.
The housing column 5 is preferably interposed between the infeed station 3a and the outfeed station 3b if the above-mentioned stations are located on the same side of the main body 3 of the oven 1. In other words, the column 5 is preferably located in the proximity of the infeed station 3a or in the proximity of the outfeed station 3b or interposed between the two. If the column 5 is located in the proximity of the infeed station 3a, when the cages 2 or mats are introduced into the oven 1, they will lie under the column 5 itself (that is, in a portion of the oven 1 defined below the column 5). Similarly, if the column 5 is located in the proximity of the outfeed station 3b, the cages 2 or mats are picked up by a portion of the oven 1 defined below the column 5.
Preferably, the infeed station 3a and the outfeed station 3b can coincide with a lower housing of the column 5.
Preferably, the infeed station 3a and the outfeed station 3b can coincide.
Alternatively, if the infeed station 3a and the outfeed station 3b are on opposite sides of the main body 3 of the oven 1 and if there is a single housing column 5, the housing column 5 may be alongside the stations (parallel to them) or positioned above them.
In the embodiment shown in Figures 1A-1F, the oven 1 comprises two housings columns 5, wherein a first column 5 is located in the proximity of the infeed station 3a (that is, above the infeed station 3a) and a second column 5 is located in the proximity of the outfeed station 3b (that is, above the outfeed station 3b). In the accompanying drawings, the first column 5 is positioned above the loading roller 4a and the second column 5 is positioned above the unloading roller 4b. In other words, the two housings columns 5 are interposed between the infeed station 3a and the outfeed station 3b.
Each housing (both in the embodiment in which there is a single column 5, and if there are two or more columns 5) is associated with respective air outlets (not illustrated) configured to define zones with different air speeds, temperatures and/or humidity inside the drying oven 1. In other words, the air outlets are configured to define flows of air for drying the paint having different speeds and/or temperatures and/or humidity as a function of the paint.
Preferably, the air outlets are equipped with opening means which can be opened and/or closed completely and/or partly, in such a way as to define specific flows of air for each housing.
Preferably, the outlets of a respective housing are independent of each other.
Preferably, the air outlets comprise fans for introducing and extracting air, in such a way as to generate a specific internal flow for each housing in which a specific cage or mat containing a specific element is to be positioned for drying.
In other words, the temperature of the air flows, as well as their humidity and the intensity of the flow are selected as a function of the specific paint to be dried applied to the element. For this reason, it is possible to perform a control of the air speed and/or temperature and/or humidity on the individual cages 2 or mats where the elements are stored.
Preferably, the air outlets may be used to guarantee a homogeneous drying cycle.
The oven 1 also comprises a movement system 6 (such as, for example, that shown in Figures 2A-2C) operatively associated with the at least one housing column 5.
Preferably, the movement system 6 is alongside the at least one housing column 5. In the accompanying drawings, the movement system 6 is operatively interposed between the two housings columns 5.
The movement system 6 is equipped with movement means configured for transporting each cage 2 or mat along a drying path defined by the infeed station 3a, by the at least one respective column housing 5 and by the outfeed station 3b.
The at least one housing of the drying path defines a drying station wherein a respective cage 2 or mat stops for a preset period of time in a zone at a specific air temperature and/or humidity.
More specifically, the drying path along which the movement means move along the cages 2 or mats involves transporting a cage from the infeed station 3a to a housing (where it will stop for the preset period of time mentioned above) and from the housing to the outfeed station 3b. Preferably, the drying path may comprise the stopping in several housings (having different temperatures and/or humidity) before transporting the cage 2 or mat from the last housing to the outfeed station 3b.
In the embodiment shown in Figures 1A-1F, the drying path is defined by the infeed station 3a, by the outfeed station 3b, by at least one housing of the first column 5 and/or by at least one second housing of the second column 5.
Each housing of the drying path defines a respective drying station in which a cage 2 or mat is stationary for preset periods of time. Preferably, the periods of time are different from each other.
The drying path is preferably achieved in 45 seconds. Depending on the type of paint and the number of movements inside the oven 1, the time a specific cage 2 or mat moves along the drying path may increase or decrease.
The movement means used to move the cage 2 or mat through the oven 1 following the drying path comprise horizontal and vertical movement means.
Preferably, the movement means comprise an elevator 6a configured to produce a vertical translation of the cage 2 or mat parallel to the at least one housing column 5. Alternatively, the movement means may comprise a stacker.
The vertical movement is performed on two columns 6b with a single drive unit and a transmission shaft. Preferably, the elevator 6a is equipped with a fall protection safety system. Preferably, the elevator 6a is equipped with a regenerative inverter for recovering energy during the lowering and braking.
Preferably, the elevator 6a can move with a maximum speed of 30 m/min (in the case of a stacker with a maximum speed of 40 m/min).
Preferably, the movement means comprise at least one slide 6b configured for making a horizontal translation of a cage 2 or mat for extracting and/or inserting it from a respective housing. The slide 6b is also configured for recovering the cages 2 or mats from the infeed station 3a and for placing them in the outfeed station 3b. The slide 6b, as shown in Figure 2A, is associated with the elevator 6a. Preferably, the horizontal movement of the cages is achieved with a maximum speed of 30 m/min. Preferably, the movement system 6 (that is, the movement means) is equipped with a plurality of slides 6b (Figures 1A-1F show, for example, three slides 6b).
In other words, the drying path is formed by a succession of horizontal and vertical movements of the cages 2 or mats. For example, with reference to the embodiment of Figures 1A-1F, the drying path may comprise a horizontal translation of the cage 2 or mat from the infeed station 3a to the central portion of the oven 1 and a successive vertical translation with which to move the cage 2 or mat to a specific housing. At this point, the cage 2 or mat containing the painted element is left stationary in the respective housing for a preset time (at this point, the cage 2 or mat can be moved to other housings where it can be stationary for other different preset times). Lastly, the cage 2 or mat is picked up with a horizontal movement and returned to the central portion where it is made to descend with a vertical movement towards a bottom portion of the oven 1 where it will then be placed, with a horizontal movement, in the outfeed station 3b. Preferably, the oven 1 is equipped with a control panel with which an operator can set the zones at different temperatures and/or humidity and the drying times. In particular, the control panel is connected to a control unit (for example a PLC) with which an operator can control the above-mentioned movement operations and the stopping times, as well as define the various areas at different temperatures and/or humidity.
Preferably, the control panel is made in the form of a touchscreen.
This invention also relates to a method for drying painted elements, the method being performed by means of a drying oven 1 according to one or more of the embodiments described above.
The method comprises preparing a plurality of cages 2 or mats and preparing the painted elements in respective cages 2 or on respective mats. In other words, the method comprises selecting a number of cages 2 or mats suitable for controlling the loading of painted elements to be dried. Moreover, the cages 2 or mats are prepared according to the dimensions of the painted elements to be dried.
The method also comprises defining zones at a different temperature and/or humidity inside the drying oven 1. In particular, the method comprises defining these zones by means of air outlets of the oven 1, associated with respective housings of the housing column 5 (or columns 5). The zones at different temperatures and/or humidity are defined as a function of the paint with which the elements are painted.
At this point, the method comprises inserting in sequence the cages 2 or mats in the infeed station of the drying oven.
For each cage 2 or mat, the method performs a step of moving along a drying path defined by the infeed station 3a, by the at least one respective housing of the column 5 and by the outfeed station 3b. In particular, the movement step is performed by transporting the cage 2 or mat from the infeed station to at least one respective housing of the column 5 corresponding to a zone at a specific temperature and/or humidity, stopping the cage in a zone at a specific temperature and/or humidity for a preset period of time and transporting the cage 2 or mat from the housing to the outfeed station. Preferably, the movement step is also performed by transporting the cage 2 or mat from one housing to another before transporting it to the outfeed station 3b.
Lastly, the method comprises extracting the cage 2 or mat from the outfeed station 3b.
The oven 1 and the method according to the invention overcome the drawbacks of the prior art.
Advantageously, the oven 1 is highly flexible in controlling drying times and controlling the different dimensions of the cages 2 or mats.
Advantageously, the oven 1 has a high modularity which makes it possible to obtain configurations suitable for supporting a large capacity of elements to be dried, both as a function of the number of elements themselves and as a function of the different dimensions and/or paint of the elements.
Advantageously, given the simple structure of the oven 1, it is also easy to maintain.
Advantageously, the oven 1 and the drying method described above can be used both for FIFO (first in first out) type cycles and for other configurations selected on the basis of the parts to be dried.

Claims

A drying oven (1) for painted elements, comprising:
- a plurality of cages (2) or mats designed to contain said painted elements;

- an infeed station (3a) for said painted elements;

- an outfeed station (3b) for said painted elements;

- at least one column (5) of housings shaped in such a way as to house respective cages (2) or mats, said housings being associated with respective air outlets configured to define zones with different air speeds, temperature and/or humidity inside said drying oven (1);

- a movement system (6), operatively associated with said column (5) of housings, equipped with movement means configured to transport each cage (2) or mat along a drying path defined by said infeed station (3a), from at least one respective housing of said column (5) and from said outfeed station (3b), said at least one housing of said drying path defining a drying station wherein a respective cage (2) or mat is preset in a zone at a specific air speed, temperature and/or humidity
said air outlets being equipped with opening means which can be opened and/or closed, even partially, in such a way as to define specific air flows for each housing;
characterised in that the air outlets comprise fans for introducing and extracting the outside air, in such a way as to generate a specific internal flow for each of said housings, in such a way as to define zones at different temperatures and/or humidity inside the oven (1) for drying a said cage (2) or mat containing a specific painted element.
The drying oven (1) according to claim 1, wherein the outlets of a respective housing are independent of each other.
The drying oven (1) according to any one of the preceding claims, comprising at least two columns (5) of housings and wherein said movement system (6) is operatively interposed between said two columns (5) of housings.
The drying oven (1) according to claim 3, wherein said drying path is defined by said infeed station (3a), said outfeed station (3b), by at least one housing of a first column (5) and/or by at least one housing of a second column (5), said at least one housing of said first column (5) and said at least one housing of said second column (5) defining respective drying stations wherein a cage (2) or mat remains for preset periods of time, preferably said periods of time being different from each other.
The drying oven (1) according to any one of the preceding claims, wherein said movement means comprise an elevator (6a) configured to perform a vertical translation of a cage (2) or mat parallel to said at least one column (5) of housings.
The drying oven (1) according to any one of the preceding claims, wherein said movement means comprise at least one slide (6b) configured for performing a horizontal translation of a cage (2) or mat for extracting from and/or inserting in a respective housing, said at least one slide being also configured for recovering said cages (2) or mats from said infeed station (3a) and for depositing said cages (2) or mats in said outfeed station (3b).
The drying oven (1) according to any one of the preceding claims, comprising a loading roller (4a) configured for introducing said cages (2) or mats in said infeed station (3a) and an unloading roller (4b) configured for extracting said cages (2) or mats from said outfeed station (3b).
The drying oven (1) according to any one of the preceding claims, wherein each cage (2) or mat comprises a main body defining a containment space for a painted element, said main body comprising at least two lateral walls, configured to retain said element, and an upper wall.
The drying oven (1) according to any one of the preceding claims, wherein said infeed station (3a) and said outfeed station (3b) coincide.
A drying method for painted elements executed using a drying oven (1) according to any one of the preceding claims, said method comprising the following steps:
- preparing a plurality of cages (2) or mats;

- preparing said elements in respective cages (2) or on respective mats;

- defining zones at different air speeds, temperatures and/or humidity inside the drying oven (1) by means of air outlets of said oven (1), associated with respective housings, as a function of the paint with which the elements are painted, said air outlets being equipped with means for opening and/or closing, even partly, in such a way as to define specific flows of air for each housing and for controlling the introduction and extraction of the outside air, in such a way as to generate a specific internal flow for each of said housings;

- introducing in sequence said cages (2) or mats in said infeed station (3a) of the drying oven;

- moving said cages (2) or mats along a drying path defined by said infeed station (3a), by at least one respective housing of said column (5) and by said outfeed station (3b), said movement step comprising:
- transporting a cage (2) or mat from said infeed station (3a) to said at least one respective housing of the column (5) corresponding to a zone at a specific air speed, temperature and/or humidity;

- actuating said cage (2) or mat in said zone at a specific air speed, temperature and/or humidity for a preset period of time;

- transporting said cage (2) or mat from said housing to said outfeed station (3b);

- extracting said cages (2) or mats from said outfeed station (3b).