MXPA00010888A - Apparatus for air-treatment of products - Google Patents

Abstract

An apparatus for air-treatment of products comprises an endless conveyor belt following through part of its length a helical path forming a stack of tiers. Side plates at one longitudinal edge of the conveyor belt form an outer cylinder wall delimiting the stack radially outwards. An inner cylinder wall delimits the stack radially inwards. Thereby, a central space is defined by the inner cylinder wall and an annular space is defined between the outer cylinder wall and the inner cylinder wall. An end closure substantially adjoins the outer cylinder wall at one end of the stack. Means are provided for blowing air through the central space towards the end closure and back through the annular space between the outer and inner cylinder walls for air-treatment of products carried by the conveyor belt in the helical path. The air is conditioned and blown through the annular space between the outer and inner cylinder walls.

Description

APPARATUS FOR TREATMENT OF PRODUCTS WITH AIR DESCRIPTIVE MEMORY The present invention relates to the treatment of products with air, mainly food products and the like, using properly conditioned air. The prior art includes various types of apparatus for such treatment, wherein the air conditioner is substantially different from the air surrounding the apparatus. Therefore, it is important that the air conditioner recirculates inside the apparatus, that is, the apparatus must be as airtight as possible and this often makes the apparatus complex and expensive. When the difference between the air conditioner and the surrounding air is not very extreme, a less complicated apparatus would be preferable. The object of the present invention is to provide a simple and cost-effective apparatus for treatment of products with air, such as cooling and testing. This object is achieved with an apparatus which comprises an endless conveyor belt that follows through part of its length, a helical path that forms a stack of layers; side plates on a longitudinal edge of the conveyor belt forming an external cylindrical wall that delimits the stack radially outwards; means forming an internal cylindrical wall delimiting the stack radically inward, whereby the internal cylindrical wall defines a central space and an annular space is defined between the external cylindrical wall and the internal cylindrical wall; an end closure that substantially joins the outer cylindrical wall at one end of the stack; means for blowing air through the central space towards the end and back closure through the annular space between the external and internal cylindrical walls for treatment of products with air carried by the conveyor belt in the helical path; and means for conditioning the air that will be blown through said space between the external and internal cylindrical walls. With this design, the outer cylindrical wall also forms the simple peripheral wall of the apparatus, which therefore does not need any separate housing. This means a significant cost reduction. The fact that the external cylindrical wall can not form a perfect hermetic wall is of minor importance, when the influence of the conditioning means in the air, for example, to heat or cool the air or to adjust its humidity, is not very substantial. In a first embodiment according to the invention, the end of the central space opposite the end closure is closed except for an entrance to the air blowing means. In this way, the air is sucked into the apparatus from the environment by the air blowing means and is returned to the environment, preferably at an open end of the annular space opposite the end closure, after having first passed through the conditioning means and then through the annular space, where the products to be treated are carried by the conveyor belt along the helical path. In this embodiment, the conditioning means are placed in the central space within the internal cylindrical wall. Alternatively, the conditioning means may be placed outside a site that accommodates the apparatus, wherein the site has an inlet from the conditioning means and an outlet. In a further embodiment, the apparatus comprises an additional end closure that substantially joins the outer cylindrical wall at the other end of the stack, where air is blown in a substantially closed path. In this embodiment, the conditioning means may be placed in the internal space within the internal cylindrical wall or may be placed in the additional end closure. Figure 1 is a schematic perspective view illustrating a conveyor belt of the prior art. Figures 2-5 are side schematic views of four embodiments of an apparatus for treating products with air in accordance with the present invention. A belt conveyor of the type shown in Figure 1 has a conveyor belt 1 adapted to follow, in the illustrated manner, through part of its length, a path comprising a number of superimposed layers extending helically to form a stack 2. The illustrated conveyor belt 1 comprises a number of mutually articulated links and can run from straight way and curves up, down and sideways. Each link comprises a lower part 3 and a spacer 4 at least on the external longitudinal side 5 of the conveyor belt 1, as seen in the stack 2. Each link can have a spacer 4 also on the longitudinal side 6 of the conveyor belt 1. The spacers 4 of an underlying layer in the stack 2 mesh and support the corresponding lateral edge of a superimposed layer. With this, the spacers 4 on the external longitudinal side of the conveyor belt 1 in the stack 2, form an outer cylindrical wall 7, and the spacers 4 on the internal longitudinal side of the conveyor belt 1 in the stack 2 form a cylindrical wall internal 8, so that an annular space 9 is formed between the outer cylindrical wall 7 and the internal cylindrical wall 8. A cylindrical central space 10 is formed inside the internal cylindrical wall 8. As an alternative to the internal cylindrical wall 8 formed by the spacers 4, the internal cylindrical wall may comprise a wall separated from the conveyor 1, for example, a wall formed on the outer periphery of a drum used to support the conveyor belt on its internal longitudinal side in the stack. In both alternatives, the annular space 9 is used as a channel for blowing air beyond the products carried by the conveyor belt 1. Normally, the air is blown vertically through the annular space 9 to cool or heat the products or to change the moisture content of the products. The alternative types of conveyor belt referred to above are described in more detail in the U.S.A. Nos. 3,938,651; 4,565,282; 4,875,343; 4,941, 567; 5,031, 751 and 5,226,291, which are incorporated herein by reference. In addition, these conveyor belts can be combined with different types of support and / or drive means found in the prior art. Some of these support and / or drive means are also described in the aforementioned patents. The conveyor belts described above can be used in an apparatus for treating products with air according to the present invention, as illustrated in Figures 2-5. In these figures, the conveyor belt 1 is illustrated very schematically as a stack 2 of layers and those parts of the conveyor belt 1 which are outside the stack 2 are not shown. In addition, the used conveyor belt preferably has spacers 4 on both longitudinal sides so that stack 2 is freestanding with the exception of the lowest layer. The embodiment illustrated in Figure 2 comprises the stack 2 and an upper cover 11 which constitutes an end closure that substantially joins the outer cylindrical wall 7 at the upper end of the stack 2. Furthermore, a horizontal division 12 is placed close to the base of the central space 10 which joins the internal cylindrical wall 8. This division 12 closes the central space 10 at its lower end with the exception of an inlet for a fan 13, which constitutes a means for blowing air from outside the stack 2 upwards through the central space 10 against the upper cover 11 where the air flow is re-directed downwards through the annular space 9 from the upper end to the lower end thereof. The annular space 9 is open at its lower end, so that the air blown through the annular space 9 can escape at that end. As shown in Figure 2, the air sucked by the fan 13 passes through a cooler 14 and / or heater 15 and / or passes through a steam generator 16 to condition the air before it passes down through the annular space 9. The configuration described above is useful when the required air velocity is not very high, for example, less than about 2 m / s, and also when the conditioning of the air that will be blown through the annular space 9 is not very substantial, for example, the decrease / increase in required temperature generated by the cooler 14 / heater 15 and / or the increase in moisture obtained through the steam generator 16. As illustrated by the arrows 17 directed from the inside of the the internal cylindrical wall 8 through the stack 2 to the outside of the outer cylindrical wall 7, none of these walls 7 and 8 need to be perfectly closed. In this way, it is possible to use a conveyor belt of the above-described types which are freestanding at least on their outer edge in the stack 2 and preferably, which are also freestanding on their internal peripheral edge in the stack 2. The supporting arrangement the conveyor belt 1 and the upper closure 11 in figure 1 is not illustrated, but they are obvious to the person skilled in the art. However, it should be noted that the stack 2 formed by the conveyor belt 1 is continuously rotating while the upper closure 11 is fixed. The embodiment illustrated in Figure 3 differs from that illustrated in Figure 2 in that a skirt 18 surrounds the lower end of the apparatus and forms a closure connecting the lower end of the outer cylindrical wall 7 and the floor beneath the apparatus. With this, the air blown upwards through the central space 10, down through the annular space 9 and out of the lower open end of the annular space 9 is recirculated when being sucked into the fan 13. Of course, this skirt 18 is much simpler and cheaper than the housing normally used in the prior art apparatus, as exemplified in the aforementioned references. The embodiment illustrated in figure 4 uses double skirts, that is, a first skirt 19, corresponding to the skirt 18 in the embodiment illustrated in figure 3 and a second skirt 20 joining the lower end of the internal cylindrical wall 8 and the floor under the device. As a result, a chamber 21 is formed below the stack 2. This chamber 21 has a first opening which coincides with the lower opening of the annular space 9 and a second opening towards the central space 10 within the internal cylindrical wall 8. In a manner more precisely, the fan 13 and the conditioning means comprising a cooler 14 and / or a heater 15 and / or a steam generator 16, are inserted between the second opening and the lower end of the central space 10. As a consequence of the opening in the chamber towards the conditioning means, no division is required at the lower end of the central space 9. Finally, FIG. 5 illustrates a further embodiment of the apparatus according to the present invention, which is identical with the embodiment illustrated in FIG. Figure 2, except that the conditioning means is placed outside a site 22 which accommodates the rest of the apparatus. The site 22 has a lower inlet 23 connected to the conditioning means (not shown) and an upper outlet 24 to expel excess air. It is important to mention that the invention is not restricted to the modalities described above and that a variety of modifications is possible within the scope of the invention as defined in the appended claims. In this way, the medium forming the internal cylindrical wall can be separated from the conveyor belt, for example, it can consist of a central drum.

Claims (12)

NOVELTY OF THE INVENTION CLAIMS

1. - An apparatus for treatment of products with air, comprising: an endless conveyor belt that follows through part of its length, a helical path that forms a stack of layers, side plates on a longitudinal edge of the conveyor belt forming a wall cylindrical external delimiting the pile radially outward and means forming an internal cylindrical wall that delimits the pile radially inward, where the internal cylindrical wall defines a central space and an annular space is defined between the external cylindrical wall and the cylindrical wall internal, characterized by a housing comprising a simple peripheral wall formed by the external cylindrical wall and an end closure that substantially joins the external cylindrical wall at one end of the stack, means for blowing air through the central space towards the closure of end and back through the annular space between the external and internal cylindrical walls a for treatment of air products carried by the conveyor belt in the helical path and means for conditioning the blown air through the annular space between the external and internal cylindrical walls.

2. The apparatus according to claim 1, further characterized in that the end of the central space opposite the end closure is closed with the exception of an inlet for the air blowing means.

3. The apparatus according to claim 2, further characterized in that the annular space between the external and internal cylindrical walls is open at an end opposite the end closure.

4. The apparatus according to claim 2 or 3, further characterized in that the conditioning means is placed in the central space within the internal cylindrical wall.

5. The apparatus according to claim 2 or 3, further characterized in that the conditioning means is placed outside a site having an inlet from the conditioning means and an outlet.

6. The apparatus according to claim 1, further characterized in that it comprises an additional end closure that substantially joins the external cylindrical wall at the other end of the stack, whereby the air is blown in a substantially closed path.

7. The apparatus according to claim 6, further characterized in that the conditioning means is placed in the internal space within the internal cylindrical wall.

8. The apparatus according to claim 6, further characterized in that the conditioning means is placed in the additional end closure.

9. The apparatus according to claim 8, further characterized in that the additional end closure comprises a chamber having a first opening towards the annular space between the external and internal cylindrical walls and a second opening towards the central space within the internal cylindrical wall.

10. The apparatus according to claim 1, further characterized in that the side plates of an underlying layer of the stack support the external longitudinal edge of a superimposed layer of the stack.

11. The apparatus according to claim 1, further characterized in that the conveyor belt has side plates on both of its longitudinal edges forming said outer and inner cylindrical walls.

12. The apparatus according to claim 11, further characterized in that the side plates of an underlying layer of the stack support the corresponding longitudinal edge of a superimposed layer of the stack.