Apparatus and method for drying/curing chemical products with a LED module

Abstract

A module for emitting radiations for curing and/or drying curable/dryable treatments like paints or glue applied on products includes a UV LED, emitting between 200 and 400 nm, or one IR LED, emitting between 600 and 1400 nm; a control circuit of the UV or IR LED; a supply circuit; a control circuit of the module; and a sensor detecting the product to be cured/dried.

Claims

1. A module emitting radiations for curing and/or drying a curable/dryable treatment applied on a product, comprising: a UV LED, emitting between 200 and 400 nm, or a IR LED, emitting between 600 and 1400 nm; a control circuit of the UV LED or IR LED; a supply circuit; a control circuit of the module; and a sensor detecting the product to be cured/dried.

2. The module according to claim 1, further comprising: a second LED emitting visible light between 400 and 800 nm, whose emission cone is overlapping to an emission cone emitted by the UV LED or the IR LED; and a dedicated control circuit for the second LED.

3. The module according to claim 2, wherein, under predetermined conditions, the module emits visible radiations only.

4. A lighting bar comprising: a plurality of modules according to claim 1, releasably mounted on a rail.

5. An oven for drying and/or curing essentially flat parts, comprising: a curing/drying booth; a conveyor on which parts to be cured/dried are conveyed; and a module emitting radiations curing and/or drying a curable/dryable treatment applied on a product, comprising, a UV LED, emitting between 200 and 400 nm, or a IR LED, emitting between 600 and 1400 nm, a control circuit of the UV LED or IR LED, a supply circuit, a control circuit of the module, and a sensor detecting the product to be cured/dried.

6. The oven according to claim 5, wherein a plurality of the modules are mounted in a lighting bar, mounted over the conveyor.

7. The oven according to claim 6, wherein an axis of the bar is disposed perpendicularly with respect to a motion direction of the parts to be cured/dried.

8. A method of curing/drying a product treated with a curable/dryable chemical product, wherein the product to be cured/dried has a position and a shape and is disposed on a conveyor, and wherein only modules of a lighting bar that generate radiation towards or incident on with the product are activated, and wherein modules of the lighting bar that that generate a radiation toward empty areas of the shape to be irradiated are kept switched off, and are switched on when areas of the shape of the product fall within an emission field of the modules, the method comprising the following steps: loading the product to be cured/dried on the conveyor; and exposing the product to an action of at least one module, wherein the at least one module comprises, a UV LED, emitting between 200 and 400 nm, or a IR LED, emitting between 600 and 1400 nm, a control circuit of the UV LED or IR LED, a supply circuit, a control circuit of the module, and a sensor detecting the product to be cured/dried, wherein, when the product passes under the at least one module, the sensor detects a presence of the product, and wherein the control circuit causes emission of UV or IR radiations from the UV LED or IR LED contained in the module.

9. The method according to claim 8, wherein emission of visible radiation from a second LEDs is also triggered, the second LED emitting visible light between 400 and 800 nm, whose emission cone is overlapping an emission cone emitted by the UV LED or the IR LED, the second LED having a dedicated control circuit.

10. The method according to claim 9, wherein a plurality of modules is mounted on the lightning bar, each of the plurality of modules emitting UV or IR radiations independently from adjacent modules, the plurality of modules being controlled by a separate feeding signal.

11. The method according to claim 10, wherein, under predetermined conditions, the emission of visible radiation only is activated from one or more second LEDs.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Further advantages and properties of the present invention are disclosed in the following description, in which exemplary embodiments of the present invention are explained in detail on the basis of the drawings:

[0037] FIG. 1 is a block diagram of a curing/drying module according to the present invention;

[0038] FIG. 2 is a longitudinal section of an oven for curing/drying painted panels;

[0039] FIG. 3 is a top view of an oven for curing/drying painted panels.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

[0040] FIG. 1 shows a block diagram of a curing/drying module in its preferred embodiment: 1 indicates the overall module. Module 1 comprises: a plurality of LEDs 2 emitting UV/IR light (i.e. emitting between 200 and 400 nm and between 600 and 1400 nm, respectively); a control circuit 3 of UV/IR LEDs 2; a supplying circuit 4; optionally a plurality of LEDs emitting visible light (comprised between 400 and 800 nm); optionally a control circuit 6 of visible light LEDs 5; a control circuit 7 of module 1, and a device 8 for detecting the panel to be cured/dried.

[0041] UV LEDs 2 have obviously the task to cure the curable materials, emitting UV radiation in suitable quality and quantity. IR LEDs 2 have the task to dry the dryable materials, emitting IR radiation in suitable quality and quantity. On the other hand, visible light LEDs 5 emit a cone of visible light substantially overlapping with the light cone emitted by UV/IR LEDs 2, so that naked eye can see that module 1 is emitting radiations. This is important in order to protect human operators, and can be very useful in case of fairs, shows, demonstrations, and even in case of apparatus adjustment.

[0042] Visible light LEDs 5 might emit light of any color; in the preferred embodiment, they emit blue visible light (between 440 and 480 nm).

[0043] Control circuits 3 and 6 are equivalent, and drive UV/IR LEDs 2 and visible light LEDs 5 with a constant current.

[0044] The supplying circuit 4 provides power supply, suitable for voltage and current, to the whole module 1. The module control circuit 7 is dependent on a sensor 8 detecting the presence of the material to be cured/dried on the conveyor in the area covered by module emission, in a known way to the skilled person.

[0045] The module 1, containing all the above-described elements, is assembled with a plurality of similar modules 1, in order to obtain a lighting bar 9 having a length corresponding to the width of a conveyor 20.

[0046] FIG. 2 shows a typical conveyor 20 conveying the painted products 21 which have to be cured/dried through the action of the UV radiations emitted by the bar 9 comprising a plurality of modules 1. Said products move under the bar 9, with an adjustable speed, typically in the order of some meters per minute.

[0047] The single modules 1 contained in a bar 9 can be switched on and off independently from each other, thanks to the presence of the detecting device 8, identifying the presence of a painted panel 21 conveyed by conveyor 20.

[0048] FIG. 2 shows a top view of the conveyor 20, of a bar 9 and of a painted product 21 to be cured, in particular a window frame, which is a rectangular frame, empty in its centre.

[0049] The modules 1 belonging to the bar 9, which is transversally arranged with respect to the movement of a conveyor 20, are switched on when the detecting device 8 of each module 1 detects the presence of a painted product 21 conveyed by conveyor 20 inside the UV radiation cone emitted by UV LEDs 2, and switched off when the product 21 passes beyond the position of that specific module 1. In the example shown in FIG. 3, the modules 1a, 1b, 1c, 1g and 1h are switched on as they are over the window frame 21, while the modules 1d, 1e, 1f, 1i, 1l are switched off in that they would not irradiate the window frame 21.

[0050] When the painted panel 21 reaches the position of the bar 9, the modules 1 in correspondence of painted panel 21 are selectively and exclusively switched on. Therefore, neither UV/IR LEDs 2, nor optionally visible light LEDs 5, which find themselves in correspondence of parts of the conveyor 20 on which at least one panel 21 is not present, are switched on. When the painted product 21 passes beyond the position of UV LEDs 2, the single modules 1 are selectively switched off

[0051] This allows to further reduce the costs and the energy consumption, and also to extend the maintenance time for LED lamps with reference to their working hours.

[0052] Without limiting in any way the various possibilities in the state of the art, the detection of the shape of a product to be irradiated with reference to its form, and specifically to frames, can be made through detection with cameras or other types of sensor which detect the product, or through sensors of the signal reflected from the conveyor and of the product, thanks to which discriminating an empty part and a full part of the product is possible. The detected signal is read directly by control circuits 3, 6, and/or 7 and determines the triggering or the switching off of the corresponding module. In an alternative operation, e.g. in the case of demonstration or fairs, and when maintenance is requested, requiring the opening of the external protecting structures of the apparatus, the same above-described functions can be performed switching on the visible LEDs 5 only, giving the visual feeling of the working of apparatus, without exposing the human operator to dangerous UV/IR radiations.

[0053] In the electrical system of an industrial apparatus, the supply voltage can be subjected to variations and even to disturbances, due to the length of connections and to the activation and deactivation of some organs of the apparatus itself, e.g. switching on and off of motors, fans, etc. As LEDs need a well-controlled power supply in order to work in an optimal way, in the preferred embodiment each module 1 has its distinct feeding circuit 4, which receives a non-accurately stabilized supply from the electrical system of the oven, while supplying precisely and without disturbances the LED control circuits.

[0054] The bar 9 supporting the modules 1 comprises an electrified rail to which the single modules 1 are removably fixed, e.g. through elastic or spring contacts. This allows an easy replacement of failing modules 1, and potentially even the possibility of fixing modules 1 of different kinds (e.g. comprising LEDs emitting a specific, different wavelength).

[0055] The radiant power required for UV light is variable according to the kind of chemical product to be cured/dried, but is about in the order of some Watt (W×cm2×sec). Indicatively, for a module 1 realized with a physical dimension of 10×10 cm, working on a conveyor advancing at 10 m/min, the typical power absorbed by each module is between 150 and 200 Watt.

LIST OF REFERENCE CHARACTERS

[0056] 1 Curing/drying module [0057] 2 UV LEDs emitting radiation comprised between 200 and 400 nm [0058] 3 Control circuit for UV LEDs [0059] 4 Supplying circuit [0060] 5 Visible light LEDs emitting radiation comprised between 400 and 800 nm [0061] 6 Control circuit for visible light LEDs [0062] 7 Control circuit of the module [0063] 8 Detecting device [0064] 9 Bar [0065] 20 Conveyor [0066] 21 Painted panel