IT202100003299A1 - SAFETY SYSTEM TO PRESERVE THE STRUCTURAL INTEGRITY OF A PLANT FOR THE PRESERVATION OF PRODUCTS IN PARTICULAR FRUIT AND VEGETABLES IN A CONTROLLED ATMOSPHERE - Google Patents

Description

DESCRIPTION of the Industrial Invention entitled:

" Safety system to preserve the structural integrity of a plant for the conservation of products in particular fruit and vegetables in a controlled atmosphere "

DESCRIPTION TEXT

The object of the invention is a safety system to preserve the integrity structuring of a plant for the conservation of products in particular fruit and vegetables in a controlled atmosphere.

To the specialists of the sector? It is well known that a controlled atmosphere is created in cold rooms for fruit preservation in which the percentage values of the gases present in the air, and in particular of O2 and CO2, are considerably modified and carefully controlled to determine a strong slowdown of the natural fruit ripening process, in order to be able to gradually place the fruit on the market in periods following that of the harvest and in an excellent state of ripeness.

because the natural process of fruit ripening is nothing else? that a respiration process, in the absence of regulation interventions inside the cell, would lead to a progressive reduction in the percentage of O2 and a proportional increase in the percentage of CO2, in addition to other products linked to cellular respiration and maturation.

It is therefore necessary to control these two gases so that the oxygen content does not fall below the minimum pre-established value for that type of fruit and, in any case, below the minimum admissible value for maintaining the fruit's respiratory metabolic processes under which a process of anaerobic fermentation of the fruit itself begins, with the transformation of the sugars contained in it into alcohol. Similarly, ? foreseen a pre-established maximum value for the concentration of CO2, which also varies according to the variety? of fruit, beyond which the content of this gas must be reduced.

In plants of the known type, the control of the content of the gases present in the conservation cells can take place, for example, through the use of activated carbon filters through which the air from the cell?s atmosphere is conveyed to control the concentration of gas contained therein and, as a non-limiting example, the gas O2 and CO2 for possible absorption. According to a pre-established succession of phases, the air from the atmosphere of the preservation cell is taken from the cell, conveyed through the filter and brought back into the cell again. This step is performed at pre-established time intervals and in combination with a subsequent regeneration step of the carbon filter in which the filter is passed through by ambient air with which they are ?washed? the activated carbons of the filter as the accumulated gas is expelled, or rather the original proportions of content of the various gases present in the natural atmosphere are re-established. In this way the filter ? ready to be used for a subsequent absorption phase.

because if not continuous, at least very frequent absorption phases are desirable to ensure correct conservation of the products present in the cell, expedients are known which provide for the use of pairs of filters which work alternately in the absorption and washing phase as, for example, described from the patent application SV2000A000035 of the same owner.

Further improvements envisage the use of particular filter washing techniques which ensure atmospheres with high gas abatement such as, for example, the reduction to oxygen values lower than 1% and in particular of the order of magnitude of about 0.5%. as, for example, described in the patent application SV2008A000066 of the same holder.

Whatever the method adopted to ensure effective control of the gases present in the atmosphere of a sealed storage cell, it must be kept in mind that variations in temperature and/or volume of said gases cause pressure variations inside the cell as a consequence of the impermeability ? and rigidity? structure of said cell which must be adequately compensated.

To this end ? it is known to use automatic valves which intervene to restore the pressure inside the cell if the guard values are exceeded.

On the other hand, there may be situations in which the cell undergoes a sudden change in pressure, for example, due to abrupt changes in temperature due to malfunctioning of the chillers or errors made by operators in checking them or the atmosphere in the cell.

There? can? determine a vacuum inside the cell for the reduction of the volume of air with consequent detachment of the structures more? weak such as the cell ceilings.

Purpose of the present invention? the creation of a system of protection of? integrity? structure of a controlled atmosphere plant with cells thanks to which the plant? able to withstand sudden changes in pressure limiting the possible damages to which the cells currently used are commonly subject.

The invention achieves the aforementioned purpose with a safety system to preserve the integrity structure of a plant in a controlled atmosphere, which plant includes a hermetic cell, one or more? access doors from outside the cell, a device for controlling the atmosphere inside the cell, in particular for controlling the levels of gases or gas mixtures making up said atmosphere such as for example carbon dioxide and/or oxygen, means of removable retainers between said cell and the external environment, which retention means are configured to open automatically when the pressure inside the cell differs by a certain amount? compared to the external pressure.

In this way, a safety system is introduced into the plant with at least one safety device which ? all the more efficient how much less? its intervention time in the presence of critical pressures which can lead to the deterioration of the cell structures.

So not only automatic valves for partial compensation of pressure differences, but real hatches/portholes? which open automatically only in critical situations to let in/out high flows of air, even in the absence of forced ventilation systems.

Are these often irreversible devices given the exceptional nature of the devices? dell?intervention, as in the case of the implementation form which instead of a hatch and the relative automatic opening devices provides for the use of weakened walls and/or membranes that break to make a large quantity flow in/outflow? of air in the shortest possible time. In this case, the restoration of the functionality? of the cell sar? possible only after having replaced the wall to which the protection devices are applied.

Further examples concern door/porthole closing devices? reversible. Among these are included, by way of non-limiting example, magnetic, tear-off closing mechanisms, for example of the hook/loop type such as Velcro, gluing, mechanical coupling or in any case comprising two parts held together by a force of entity Note. By suitably calibrating this force? You can control the pressure difference at which the device opens. All without the use of electrically controlled parts based on sensors capable of detecting the pressure inside the cell in order to guarantee intervention even in the absence of electricity.

Further characteristics and improvements are the subject of the subclaims.

The characteristics of the invention and the advantages deriving from it will become clearer from the following detailed description of the attached figures, in which:

fig. 1 shows a circuit diagram of a system for preserving products, in particular fruit and vegetables, in a controlled atmosphere according to the prior art comprising, by way of example , a single cell and a single filter.

fig. 2 shows a principle diagram of the integrity protection system? structural in the executive and non-limiting form of a hatch to be applied on a wall of the cold room of the system in the previous figure..

With reference to figure 1, a plant for preserving fruit in a controlled atmosphere typically comprises a refrigerated storage cell 1 having an outlet 101 and an inlet 201. The inlet 201 is connected to a terminal 104 of a servo-controlled three-way valve 4. The remaining two terminals 204, 304 of the valve 4 are in communication respectively with the ambient air and with the terminal 202 of the activated carbon filter 2. The other terminal 102 of the filter? connected with terminal 203 of pump or fan 3. Terminal 103 of pump or fan 3 ? connected to the terminal 305 of a second servo-controlled three-way valve 5. The remaining two terminals 205, 105 of the valve 5 are in communication respectively with the ambient air and with the outlet 101 of the cell 1. Does the pump or fan 3? advantageously an inverter fan with variable capacity controllable by a unit? control 7 which underlies the functioning of the entire system. To the unit control 7 are also connected to the commands of the three-way valves 4 and 5 for correct setting of the absorption and regeneration cycles.

The functioning of the plant? the following. In the regeneration phase of the filter 2, the valve 5 puts the inlet 103 of the pump or the fan 3 in communication with the external environment, closing the communication with the outlet 101 of the cell 1. The pump or the fan 3? controlled so as to generate an air intake flow from the outside in the filter 2. The valve 4 at the outlet of the filter 202 ? switched to such a position as to connect the outlet 202 of the filter 2 with the external environment and to close the inlet 201 of the cell. In this way, the gas absorption filter 2 is made to pass through a flow of ambient regeneration air which, by way of a non-exclusive example n? limiting, it eliminates the absorbed and accumulated CO2.

The regeneration phase is followed by an absorption phase in which the valves 4 and 5 are switched to a position such as to allow direct passage of the air from the cell 1 through the filter 2 and the pump or the fan 3 from the outlet 101 to the inlet 201 of cell 1 without there being communication with the external environment.

The absorption phase is followed by the regeneration phase as previously described. The repetition frequency of the atmosphere control cycle can? vary according to the environmental conditions, the volume of the cell as well as? the type of goods and the quantity? of goods stored in cell 1. During the regeneration phase, the flow rate of ambient air is increased with respect to the flow rate of air coming from the cell in the absorption phase to compensate for the different duration of the two phases.

Can there be more? of a unit? filter as for example described in the patent application n. SV2008A000066 of the same owner to be considered an integral part of this description.

Whatever the cell atmosphere control mechanism is used, the need arises to prevent sudden changes in temperature from causing corresponding sudden changes in pressure inside, generally decreasing, which can compromise the stability of the cell. both of the cell and of the structures housed therein.

because cell 1 generally has one or more? walls sealed to the outside, a way to rebalance the pressure? that of acting on said walls by introducing, for example, a weakening area capable of breaking when the pressure differences on the sides of the wall ? higher, in absolute value, than a given threshold.

This zone of weakening pu? be of the same material as the wall, but thicker? small or of different material, for example, more? brittle, such as a membrane. In this case, the intervention of the protection, determining a breakage, is of the irreversible type, or the restoration of the functioning of?the plant can? take place only after having replaced the wall or the membrane that is ? route.

Alternatively or in combination? is it possible to act on the retention devices of one or more? doors, windows, portholes? and similar safety closures of dimensions such as to ensure a flow rate of air flowing into/outflowing into/from the cell when open such as to ensure rapid rebalancing of the pressure in the cell. In this case, the overcoming of the critical pressure condition determines the release of these devices with consequent opening of the closures with which these devices are associated.

In this way there is no breakage of any element of the system, so? realizing a reversible type safety device, that is resettable in the mode? operational even by an operator without the intervention of a maintenance team.

The reversible devices can advantageously be used alone or in combination with at least one irreversible device. In this case, making sure that the reversible devices have lower pressure intervention thresholds? low, the irreversible devices can represent a second level of safety of the system capable of intervening as an aid or as an alternative to the reversible devices.

Figure 2 shows in a very exemplified and non-limiting way a device that can be applied to a cell wall of a conservation plant. It is substantially a movable wall 10 which acts as a bulkhead for closing an opening 11 provided in a sealed wall towards the outside of the cell 1. In the figure, the opening 11 is? identified with an inverted U profile, but obviously pu? have any shape with the movable wall 10 having a complementary shape or in any case such as to cover the entire opening 11 when placed next to said opening.

The movable wall 10 is held in the closed position of the opening 11 by retaining means 12. The retaining means 12 exert a certain force in the closing direction of the door and/or of the safety closures. In the specific example of the figure, there are three retaining devices, one for each side of the U and they act in the direction indicated by the arrows Pm1, Pm2, Pm3 ie? from the outside to the inside of the cell 1 with the movable wall located outside the cell 1 to counteract a decrease in pressure in the cell. Obviously the movable wall 10 can? likewise be placed inside the cell with the retention means 12 acting in the opposite direction to counteract an increase in pressure in the cell 1.

The retention means 12 can comprise one or more? magnets, a tear-off closure mechanism, for example of the hook / loop type such as Velcro, gluing, mechanical coupling or in any case comprising two parts held together by a force of magnitude? note (Pm1 Pm2 + Pm3).

When is the pressure difference between the outside and inside of the cold room (Pext - Pint) ? greater than the sum of the forces exerted by the retaining means (Pm1 + Pm2 + Pm3) for example due to a reduction in the internal pressure, the movable wall detaches from the cell wall so? allowing a flow of air from the outside to the inside which balances the pressures in play.

Advantageously one or more? walls can comprise an opening delimited by an annular frame 14 which has an abutment edge on the side facing towards the inside or towards the outside of the cell. The retaining means in this case advantageously comprise a closure element provided with a corresponding flanged edge for abutting the abutting edge of the frame inside or outside the compartment.

The retaining means can comprise a magnetic, tear-off closing mechanism, for example of the hook/loop type such as Velcro, gluing, mechanical coupling or in any case comprising two parts held together by a force of magnitude Note. In this case the first of the two parts ? advantageously associated with the abutting edge of the annular frame while the second of the two parts? associated with the abutment edge of the closing element or vice versa.

Of course the? Invention is not? limited to the embodiments described above, but pu? be widely varied. For example, can be provided more? cells and more filters in parallel. Sensor means can also be provided for generating a signal as a function of the pressure in the cell or in the circuit and a unit advantageously sensitive to said signal and configured to emit an alarm and/or control the opening of the doors according to this signal. In this way a further level of safety is obtained, in particular if the control unit ? configured to intervene on the opening of the doors before the intervention of the safety devices described above. All without abandoning the guiding principle set out above and claimed below.

Claims (11)

1. Security system to preserve the integrity? structure of a plant in a controlled atmosphere, which plant comprises a watertight cell 1, one or more? access doors from the outside to the cell 1, a device for controlling the atmosphere inside the cell (2, 3, 4), in particular for controlling the levels of gases or gas mixtures making up said atmosphere such as for example dioxide carbon and/or oxygen, characterized in that said system comprises removable retaining means (12) between said cell 1 and the external environment, which retaining means (12) are configured to automatically snap open when the pressure inside of cell 1 differs by a certain amount? compared to the external pressure. 2. System according to claim 1, wherein the cell (1) has one or more? walls sealed towards the outside, the retaining means (12) comprising a weakening zone of said one or more? walls likely to break when the pressure differences on the sides of the wall ? higher, in absolute value, than a given threshold. 3. System according to claim 1 or 2, in which the cell (1) has one or more? walls sealed towards the outside, the retaining means (12) comprising a membrane for closing an opening provided in said one or more? walls likely to break when the pressure differences on the sides of the wall ? higher, in absolute value, than a given threshold. 4. System according to one or more? of the preceding claims, wherein the retention means (12) are associated with one or more? access doors (11) to the cell (1). 5. System according to one or more? of the previous claims, comprising one or more? doors, windows, portholes? and similar safety closures of the cell (1) of such dimensions as to guarantee a flow rate of air flowing into/outflowing into/from the cell (1) when open such as to guarantee a rapid rebalancing of the pressure in the cell (1), the retention means (12) being associated with said safety closures. 6. System according to claim 4 or 5, wherein the retaining means (12) comprise one or more? magnets which exert a certain force in the closing direction of the door and/or safety locks. 7. System according to one or more? of the previous claims 4 to 6, wherein the retaining means (12) comprise a tear-off closure mechanism, for example of the hook/loop type such as Velcro, glued, mechanically coupled or in any case comprising two parts held together by a force of entity? Note. 8. System according to one or more? of the previous claims, in which one or more? walls of the cell (1) comprise an opening delimited by an annular frame (14), said frame having an abutment edge on the side facing towards the inside of the cell, the retaining means (12) comprising a closing element equipped with corresponding flanged edge for abutting with the abutting edge of the frame (14), the retaining means acting to hold the two edges in the abutting position. 9. System according to one or more? of the previous claims, in which one or more? walls of the cell comprise an opening delimited by an annular frame, said frame have an abutment edge on the side facing towards the outside of the cell, the retaining means comprising a closing element equipped with a corresponding flanged edge for collision with the edge abutment of the frame, the retaining means acting to hold the two edges in the abutment position. 10. System according to one or more? of the preceding claims, wherein the retaining means (12) comprise a magnet or tear-off closing mechanism, for example of the hook/loop type such as Velcro or gluing or mechanical coupling or in any case comprising two parts held together by a force of entity known, the first of the two parts being associated with the abutting edge of the annular frame, the second of the two parts being associated with the abutting edge of a closing element or vice versa. 11. System according to one or more? of the previous claims, in which one or more? sensors to detect the pressure inside the cell (1) and a unit? control configured to read the values detected by the sensors and drive electric or electromechanical actuators that control the? opening of one or more? cell doors before the pressure reaches the intervention level of the check means (12).