WO2005106356A1

WO2005106356A1 - Improved process and apparatus for actuating and regulating forced circulation of air in cold-storage rooms

Info

Publication number: WO2005106356A1
Application number: PCT/IT2005/000238
Authority: WO
Inventors: Francesco Brancato
Original assignee: Brancato Domenico Di Francesco Brancato & C. Snc
Priority date: 2004-05-03
Filing date: 2005-04-22
Publication date: 2005-11-10
Also published as: ATE487100T1; EP1743126B1; DE602005024538D1; ES2353945T3; ITME20040005A1; EP1743126A1

Abstract

Apparatus (10) for forced circulation of air in cold-storage rooms said air circulating inside stacks of containers (120) of market-garden produce, said containers (120) having apertures (135) in both sides, said apparatus (10) comprising an electric fan (20) and an upper crosswise box (60) to hold waterproof sheeting (62), so that when said sheeting (62) is pulled out to create a sort of tunnel between the stacked containers of produce, forced circulation of air can flow inside said tunnel and therefore inside the containers, placing the suction mouth (22, 34) at the position of the tunnel and the delivery mouth (38) externally to it, or vice versa.

Description

Improved process and apparatus for actuating and regulating forced circulation of air in cold-storage rooms

The invention concerns cooling of fruit and vegetables in refrigerating rooms.

After harvesting, the temperatures of crops of fruit and vegetables tend to rise and a process of ageing sets in.

The cooling techniques applied in conventional cold-storage rooms partially solve the problem as rapid and uniform cooling preserves the quality of these products by inhibiting the growth of the micro-organisms responsible for decay, limiting enzymatic activity, preventing loss of water and reducing the production of ethylene.

As there are numerous cooling techniques available, mention will here be made of those most comparable with the above invention.

Cold-storage rooms

A flow of cold air reaching the product from an evaporator, becomes warm and tends to rise returning to the evaporator and completing the cycle.

The speed of air put into circulation is usually 60-120. m/min.

This method requires a good deal of space, partly because cooling time is fairly long.

Forced circulation of air This type of cooling differs from the cold-storage room technique because of the greater speed at which the air comes in contact with the product, and is applicable to most products without causing any difficulties. Inside the room the airflow is directed along suitably pre-arranged channels, flow being created in some cases by supplementary fans and improvised tunnels.

In refrigeration rooms of this kind passage of air is assisted by a slight pressure gradient created by a fan placed in the passageway between two rows, one opposite the other, of produce in containers standing on beds.

The passageway between rows can be made into a tunnel by means of a cover, or curtain, which may even consist of ordinary waterproof sheeting.

The ventilator can operate by pressure or by suction. The cross section of the tunnel must be calculated beforehand according to the type of produce, packaging and number of containers.

In a depression system, cold air is drawn in from the refrigeration room after passing around the stacked produce which is thus cooled.

A fan can be placed on the ground outside the curtain in which a hole is made and through which air is drawn in.

The fan must be easy to move so that warm air is blown towards the evaporator.

For the most part these are improvised attempts adopted by operators who use makeshift cold-storage systems. Satisfactory results are not always achieved partly because fan power must be properly calculated.

Pressurised cold-storage for bananas

These represent the most recent innovations and are the result of variations made to preceding systems.

The curtain is here replaced by cushions or airbags that inflate automatically, as programmed, and are placed on the beds, where the containers of bananas are stacked, in such a way that the air passes inside the containers.

In the more sophisticated installations depression takes place from below upwards as far as the roof of the refrigeration room. Fans are situated high up inside the evaporators on the central passageway.

Two double rows of two-layered containers of bananas can be stacked in these refrigeration rooms. Pressure in the central passage is kept lower than in the free spaces in the room outside the passage.

This system gives the best results compared with former methods of ripening that involved moving and unpacking each container of bananas. In cold-storage rooms of the conventional type, slow refrigeration makes it impossible to cool highly perishable products satisfactorily since it requires suitable stacking to ensure good ventilation and involves condensation of steam on the externally situated products that cool more quickly, said steam being partly given off by the products stored in the central area where ventilation is slower. Further, in such types of cold storage it is impossible to carry out an efficient ripening process for green bananas. In the world today the process of ripening of green bananas in ordinary cold-storage rooms should always take into account certain chemical and physical factors, namely measurement of ethylene gas, regulation of humidity, temperature levels, composition of the atmosphere etc., as well as the extent to which all the containers have to be moved. These operations are carried out manually by empirical means so that good results cannot always be ensured. As mentioned above, to make sure that the process will finally produce a ripe yellow banana ready for consumption, conventional methods of ripening require manual execution of a series of checks and other operations involving moving the containers from the beds and arranging them singly in echelon formation taking them from each pallet. On the other hand, cold-storage rooms with "forced circulation of air and a curtain", and the "pressurised cold-storage rooms with airbags" are used in order to contain labour costs, facilitate loading and unloading, and avoid having to move containers of produce, the aim being to achieve uniform levels of ripening, colour, quality and, consequently, of profit. The above invention offers considerable advantages compared with the systems described above, as will now be explained.

Subject of the invention is an apparatus, substantially parallelepiped in shape, designed to produce and regulate forced circulation of air in cold- storage rooms in a wholesale market-gardening establishment where the products are all packed in a standard type of container, having side walls with apertures, arranged in two rows each consisting of pairs of stacked containers on either side of a central passageway, the stacked containers forming a wall at the back and at the front.

The invented apparatus presents a flat front wall, and comprises an internal electric fan with inflow and outflow apertures, and a horizontal crosswise box fixed to the flat front wall; said box contains wateφroof sheeting wound round a longitudinal roller and is set at a height substantially in line with the top of the stacked containers of market-garden produce .

By placing the front of the apparatus against the two front walls formed by the stacked containers of produce, and by laying the waterproof sheeting over the passageway between them and then lowering it like a curtain over the two rear walls of containers, a tunnel is formed into which, on actuating the electric fan,, a flow of air is forced, said air then passing through the openings in the outer and inner sides of the stacked containers placed to form a passageway in between them.

In one type of execution the suction mouth of the electric fan is situated on the flat front wall of the apparatus opposite the tunnel, while the delivery mouth is placed at the rear.

Preferably associated, at a lower level, to the suction mouth of the electric fan, is a second suction mouth also connected to the delivery mouth. In another type of execution the delivery mouth of the electric fan is situated on the flat front wall of the apparatus opposite the tunnel, while the suction mouth is situated on a wall of the apparatus external to the tunnel.

The delivery mouth is preferably fitted with horizontal blades whose inclination can be adjusted to direct delivery of air in the most effective manner.

The apparatus preferably stands on four wheels and is fitted with a brake; in this way it can be moved about inside the cold-storage room or transferred to any other such room. The box containing the waterproof curtain is preferably fitted with a high- ratio winch so that the curtain can be wound up and let down manually by means of an external rod.

The curtain is preferably made rigid by application of crosswise metal strips to withstand the effect of forced circulation of air.

In one type of execution the electric fan is of the scroll type. In one type of execution the electric fan communicates with the delivery mouth through an intermediate chamber containing electric heating elements so that, when necessary, the air circulating inside the room can be warmed.

The apparatus comprises a control panel with two digital temperature regulating devices fitted with displays, these being respectively connected to two probes, one at the suction mouth for automatic regulation of the temperature of air in circulation by turning on the heating elements or leaving them turned off, the other probe penetrating inside the products to check internal temperature in order to ensure that the temperatures as programmed are respected;, this is done by stopping the electric fan or starting it up as required. The control panel comprises a speed variator for the electric fan so that room temperature can be adjusted according to the type of fruit or vegetable. Strips of foam material are applied like a sort of projecting frame to the front of the apparatus so that, when said apparatus is moved against the wall formed by the stacked, containers, opposite the passageway, the strips of foam material form an air seal. The electric fan can also be switched on and off by means of a timer so as to make use of possible differences in heat between day and night. In one type of execution the delivery mouth can be orientated in the way most suited to the cold storage room in which the apparatus is situated. In one type of execution the waterproof curtain is about m 1.5 wide ensuring ample coverage of the passageway area only between the stacked products. In one type of execution the overall dimensions of the apparatus are m. 0.60 x 1.00 2.45. In one type of execution diameter of the suction mouth is m 0.32 while dimensions of the delivery mouth are m. 0.96 x 0.94.

The invention offers evident advantages.

The invented apparatus can function not only in conventional types of cold- storage rooms where more beneficial systems of refrigeration by forced circulation of air can be applied, but also offers a possibility of exceptional importance, namely that of adaptability to the requirements of pressurised cold-storage rooms since the invented apparatus can easily and inexpensively produce the same effects as those obtainable with pressurised cold-storage in this way avoiding the high costs for investment in banana ripening.

The advantages of quality and hygienic safety, offered by rapidly and uniformly refrigerated fruit and vegetables, are maintained throughout the all stages of marketing right to that of consumption. The process slows down the rate of respiration and transpiration of fruit and vegetables and consequently of their metabolism.

Ripening proceeds more slowly compared with that occurring when the same produce is refrigerated in ordinary cold-storage rooms.

On obtaining a uniform control over temperature and ventilation, fruit and vegetable produce can, by losing less weight, reach high levels of quality as regards colour and pulp, while improving keeping possibilities as well. A saving in time and labour over loading and unloading, especially where goods packed in containers stand on a bed, as the produce (bananas for example) does not have to be taken out of the containers. No handling of containers is in fact needed, contrary to what is required in conventional types of cold-storage rooms.

The apparatus is highly flexible in use and easy to move inside any kind of cold-storage room or in the outside environment.

Operational safety and simplicity, and a saving of energy as the cooling fans work intermittently and not continuously.

No need to design new structures or cold-storage facilities with forced circulation of air. The cooling and ripening process is carried out to suit the needs of the client and of the market, namely lasting between two and five hours according to temperature, to the type of packaging and type of produce.

To sum up these advantages, it may be said that results achieved show a great improvement on those obtainable with ordinary cold-storage facilities in which air circulates under pressure or where forced suction of air is used, as in the most advanced models of these facilities.

Characteristics and purposes of the invention will be made still clearer by the following example of its execution illustrated by diagrammatically drawn figures.

Fig. 1. Mobile apparatus for refrigeration by forced circulation of air, perspective view seen from one side.

Fig. 2. As in Figure 1, perspective view seen from the other side.

Fig. 3. Control panel. Fig. 4 The apparatus in use inside a cold-storage room in which a sort of tunnel has been created between the containers of products.

The mobile apparatus 10 is formed of a substantially parallelepiped, oblong, vertical metal structure and .consists of four main sections 12, 14, 16, 18.

The socket 17 for electric current can be seen at one side of main section 16. Said main section 16 houses a scroll-type electric fan 20 with two suction mouths, a front mouth 22 covered by netting 23, and a rear one fed by a front suction mouth 34, with netting 35.

Said main section 16 is separated from the upper main section 14 by a partition 30 in which there is an opening 32. The set of electric elements 45 is situated inside said main section 14.

The delivery mouth 38, with grille, is situated on the top main section 12. .

When the electric fan 20 is working, air drawn in through the front mouth

22 (arrows 50) and through the. front mouth 34 (arrows 52), passes (arrows

54) through the opening 32 in the partition 30 and enters the top main section 12 from which it emerges (arrows 56) through delivery mouth 38.

Over said delivery mouth is a grille with horizontal blades the inclination of which is adjustable. On the front of main section 14 is the box 60 (Figures 1 and 2) that houses the roller 61 round which the waterproof sheeting 62 is wound. The sheeting 60 is of plastic or other material reinforced with strips of aluminium 66 and by a bar 68 at its end, and is unrolled by a semi- automatic mechanism worked by a winch 70 (Figure 2).

Small wheels 75 to facilitate movement are fixed to the base of the apparatus 10.

Applied to the flat front of the apparatus 10 is a sort of projecting frame 77 of foam material the presence of which enables an air seal to be formed between the foam and the end of the stack 120 of containers 130 of fruit and vegetables, when the apparatus is put into action.

A control panel 80 (Figures 2 and 3) is situated on one side of the apparatus, said panel comprising two digital temperature regulators 92, 94 connected respectively to two probes 96, 98 (Figures 1 and 2). The probe 96 fits in at the lower mouth 34 of the apparatus 10 so that one temperature regulator 92 can regulate temperature and if necessary turn on the electric heating elements 45 to warm the air in the cold-storage room. The other temperature regulator 94, connected to the probe 98 (Figure 2) for insertion among the products, enables t e electric fan 20 to be automatically turned off, or its speed varied until the set temperature has been reached.

The control panel 80 also comprises the main switch 82, fuses 84, electric voltage pilot lights 86, pilot light 88 to indicate heating, amperometric protector 100 for the electric motor, relay 102 to activate the motor, relay 104 to activate the electric heating elements 45, and further comprises device 106 for variable frequency speed control (NFD) of the electric fan 20 in proportion to variations in ambient temperature.

Figure 4 illustrates the apparatus 10 placed inside an ordinary cold-storage room 110, with its door 112, for access, and evaporator 114. The room 110 is filled with two double rows 125 and 126 of containers 120 of market-garden produce, each double row standing on its bed 122 and 123, and consisting of substantially identical pairs of containers 130 for said produce. In each lateral opposing face of each of these containers 130, generally made of cardboard, there is at least one pair of apertures 135. In Figure 4 only a part of row 125 has been shown; this in order to allow a better view to be gained of the apparatus 10, especially of its front, and therefore a clearer understanding of the way it functions.

It will also be seen that almost the entire length of the sheeting 62 has been pulled out from the box 60, so that one area 63 of sheet covers the upper surface of the stack 120, the remainder 64 covering its rear end, while the front end of the stack 120 substantially matches with the apparatus 10 forming a seal with the projecting frame 77 of foam material and creating a sort of tunnel, marked with number 72.

On activating the electric fan 20 inside the apparatus 10, a suction force, indicated by arrows 140, is created inside the tunnel 72, also passing through the rows of produce 125 and 126. The air, drawn in by the electric fan situated inside the apparatus 10, emerges (arrows 56) from the delivery mouth 38 and rises towards the evaporator 114.

Continuous circulation of air under pressure is thus created contributing to preservation of the fruit and vegetables substantially as occurs in the pressurised cold-storage rooms described.

Claims

Apparatus, substantially parallelepiped in shape, for actuating and regulating forced circulation of air in cold-storage rooms, said air passing through two double rows of stacked market-garden produce packed in substantially identical containers having apertures one opposite another in their sides, said double rows being aligned one on either side of a central passageway and forming pairs of vertical walls at their front and rear ends, characterized in that it comprises a front flat wall, an internal electric fan, two suction mouths and one delivery mouth, and comprises a crosswise horizontal box, mounted on said flat front wall, said box containing waterproof sheeting wound round an internal longitudinal roller, said box being situated at a level substantially aligned with that of the upper surface of said rows of containers of market-garden produce so that, when the front face of the apparatus is moved up against the pairs of front walls of the stacked rows of said produce, and the sheeting is pulled over the passageway between the rows of stacked containers and down over the pairs of rear walls formed by the stacks, a sort of tunnel is created along which, when the electric fan is working, a flow of forced air passes said flow also passing through the apertures in the external and internal sides of the containers that form the passageway between the double rows of stacked containers,

2. Apparatus as in claim 1- characterized in the one suction mouth of the electric fan is situated on the flat front wall of the apparatus, at a position opposite to the tunnel, while the delivery mouth is situated at the rear of the apparatus.

3. Apparatus as in claims 1 and 2, characterized in that a second suction mouth is associated, at a lower level, to the first suction mouth of the electric fan, said second mouth being connected to the delivery mouth.

4. Apparatus as in claim 1- characterized in that the delivery mouth of the electric fan is situated on the flat front wall of the apparatus at the position of the tunnel, while the suction mouth is made in a wall of the apparatus external to the tunnel.

5. Apparatus as in claim 2, characterized in that the delivery mouth is fitted with horizontal blades the inclination of which can be adjusted to orientate delivery as required inside the cold-storage room.

6. Apparatus as in claim 1, characterized in that it stands on four wheels and is fitted with a brake, so that it can be easily moved from one place to another inside the cold-storage room or to any other such room.

7. Apparatus as in claim 1, characterized in that the upper box is fitted with a high-ratio winch so that the waterproof sheeting can be unwound manually by means of a rod.

8. Apparatus as in claim 1, characterized in that the sheeting is made rigid by application of crosswise metal strips enabling it to withstand the effect of forced circulation of air.

9. Apparatus as in claim 1, characterized in that the electric fan is of the scroll type.

10. Apparatus as in claim 1, characterized in that the electric fan communicates with the delivery mouth through a chamber containing electric heating elements for warming the air in circulation when necessary.

11. Apparatus as in claims 1, 2, 3, characterized in that it comprises a control panel on which are two temperature regulators with displays, connected respectively to two probes, one of which is situated at the suction mouths for automatic regulation of the temperature of air in circulation and, for this purpose, turning on or not turning on the heating elements, the other probe being used to penetrate among the market-garden produce to keep a check on its internal temperatures, turning off or restarting the electric fan to maintain temperatures at the preset levels.

12. Apparatus as in claims 1 and 11, characterized in that on the control panel there is a speed variator for the electric fan to regulate ambient temperature according to the type of fruit and vegetables to be preserved.

13. Apparatus as in claim 1- characterized in that applied to its flat front surface is a sort of frame of foam material in order to create a, seal when the apparatus is placed at the position of the passageway against the wall formed at the front end of the stacked containers of fruit and vegetables.

14. Apparatus as in claim 1. characterized in that the electric fan can be switched off and on by means of a timer so as to make the best use of possible heat differences between day and night.

15. Apparatus as in claim 1- characterized in that, in one type of execution, the delivery mouth can be orientated in the most suitable way according to the cold-storage room in which the apparatus is housed.

16. Apparatus as in claim 1, characterized in that the width of the sheeting is approximately between m. -1.5 and 2.5 so that it can amply cover the passageway between the rows of stacked containers of fruit and vegetables.

17. Apparatus as in claim 1, characterized in that its overall dimensions are m. 0.60 x 1.00 x 2.45.

18. Apparatus as in claims 1, 2 and 3, characterized in that the diameter of the suction mouths is m. 0.32 while the dimensions of the delivery mouth are m. 0.96 x 0.94.