Tunnel for Drying Fruit and Vegetables

Abstract

The present disclosure consists of a drying tunnel for fruits or vegetables which comprises an impulsion and heating chamber and a plenum, configured for receiving an outgoing hot air generated in the impulsion and heating chamber by the generator, so that the plenum comprises openings arranged in a staggered pattern, located on the lower surface thereof, with an opening density between 150 to 300 openings per square meter, wherein said openings are configured for expelling a distributed hot air from inside the plenum in a perpendicular way towards a conveyor system, configured for moving fruits and vegetables to be dried.

Claims

1. A drying tunnel for fruits or vegetables comprising: an impulsion and heating chamber; and a plenum, configured for receiving an outgoing hot air generated in the impulsion and heating chamber; wherein the plenum comprises: openings, with a cross-section shape selected from the group consisting of circular and oval, arranged in a staggered pattern, located on a lower surface of said plenum, with an opening density between 150 to 300 openings per square meter; wherein said openings are configured for expelling a distributed hot air from inside the plenum in a perpendicular way towards a conveyor system, configured for moving fruits and vegetables to be dried; wherein the plenum comprises a rectangular cross-section decreasing along the length thereof, as it moves away from the inlet of the outgoing hot air from the impulsion and heating chamber; and wherein said decreasing rectangular cross-section is configured for maintaining the pressure conditions inside and releasing distributed hot air under the same pressure and temperature conditions throughout the entire conveyor system, achieving a uniform flow distribution over all the openings by means of the geometry of the plenum.

2. The drying tunnel for fruits and vegetables according to claim 1, wherein the impulsion and heating chamber comprises a turbine which generates air at constant pressure and a heat generator that heats the air generated by the turbine.

3. The drying tunnel for fruits and vegetables according to claim 1, wherein the outgoing hot air from the impulsion and heating chamber received by the plenum has a temperature between 25 and 45° C.

4. The drying tunnel for fruits and vegetables according to claim 1, wherein the plenum has a static pressure between 300 and 800 Pa when it receives the outgoing hot air from the impulsion and heating chamber.

5. The drying tunnel for fruits and vegetables according to claim 1, wherein the distributed hot air expelled through the openings has an outlet velocity between 20 m/s and 50 m/s.

6. The drying tunnel for fruits and vegetables according to claim 1, further comprising at least one aspirator configured for suctioning the distributed hot air expelled through the openings, and directing suctioned by the aspirator through at least one lateral duct into the impulsion and heating chamber, generating a flow of hot air inside the tunnel, due to the depression generated, as well as a mechanical dragging of the water.

7. The drying tunnel for fruits and vegetables according to claim 6, wherein the suctioned air by the aspirator comprises a percentage between 50 and 90% of the distributed hot air expelled through the openings.

8. The drying tunnel for fruits and vegetables according to claim 6, wherein the suctioned air, which is redirected to the impulsion and heating chamber, is mixed with air external, which is at a lower temperature than the suctioned said external air, entering through a grid, the mixture of said air being used for reuse in the drying the fruits.

9. The drying tunnel for fruits and vegetables according to claim 1, wherein the conveyor system consists of a roller conveyor.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0036] To complement the description provided herein, and for the purpose of helping to make the features of the present disclosure more readily understandable, said description is accompanied by a set of drawings constituting an integral part of the same, which by way of illustration and not limitation represents the following:

[0037] FIG. 1 shows an axonometric rear perspective of the fruit drying tunnel, without the conveyor system to be able to view the openings in the lower surface.

[0038] FIG. 2 shows a projection of the lower level of the drying duct wherein the density and location of the staggered openings through which the hot air comes out across the entire surface is shown.

[0039] FIG. 3 shows an external projection of the profile of the drying tunnel together with the complete mechanism for moving the fruit, as well as the air recirculation ducts.

[0040] FIG. 4 shows a projection of the upper level of the entire drying tunnel, which enables the position of the recirculation ducts to be appreciated.

[0041] FIG. 5 shows an isometric perspective view of the entire tunnel.

[0042] FIG. 6 shows a profile view of how the fruit is dried by expelling hot air through the openings towards the fruit.

[0043] FIG. 7 shows a profile perspective of the complete drying tunnel with the arrows that simulate the air direction at each interval.

DETAILED DESCRIPTION OF THE INVENTION

[0044] As can be seen in the figures, especially in FIG. 7, the tunnel for drying fruits and vegetables that is the object of the present disclosure is made up of an impulsion and heating chamber (2) which comprises a turbine and a heat generator, so that in this space an outgoing hot air current (6) is generated that enters a plenum (3) at constant pressure.

[0045] This plenum (3), in the shape of a rectangular duct, has a rectangular cross section that decreases along the length thereof, such that it enables the pressure conditions inside it to be maintained, a pressure between 300 and 800 Pa.

[0046] As can be seen in FIG. 2, on the lower surface (1) of the plenum there are circular openings (10) in a distribution of approximately 300 openings/m.sup.2 which enable the outlet of distributed hot air (4) towards a roller-based conveyor system (9), wherein fruits or vegetables that are wet from previous cleaning or waxing processes, move in order to be dried.

[0047] This distributed hot air (4), expelled through the openings (10) of the lower base (1) impacts directly on the surface of the fruits or elements present in the conveyor system (9) in a perpendicular way, such that, due to the speed and temperature thereof, it dries them during the period in which they are moving through the tunnel.

[0048] As the openings (10) have a staggered arrangement throughout the expelling surface (1), all the portions of the fruits present in the conveyor system receive the hot air flow, from the moment they enter the tunnel until they come out, at a constant speed, in an efficient process wherein the elements to be dried are not damaged.

[0049] The distributed hot air (4) used in the drying process is suctioned by two aspirators (7) located on the sides of an initial section of the conveyor system (9), under the impulsion and heating chamber (2), improving the air inlet through the holes (10) due to the depression created in the aspiration and dragging of the water that the fruit carries on the surface.

[0050] These aspirators (7) generate a suctioned air flow (5) which, despite having dried the humidity present in the tunnel, still maintains a higher temperature than the outside, so it is recirculated through two ducts (8), one for each aspirator (7), towards the impulsion and heating chamber (2) in order to be reused again, requiring less energy from the heat generator in order to increase the temperature of the outgoing hot air (6).

[0051] To reduce the humidity that this suctioned air flow (5) may have, it is mixed with air from the outside that comes from a grid (11) located at the rear portion of the impulsion and heating chamber (2), providing the air mixture with optimal conditions for drying that are controlled in order to regulate the heating degree.