WO2006122935A1

WO2006122935A1 - Method and plant for removing dissolved oxygen and/or cooling liquids or fluid agglomerates through the use of gases or liquefied gases

Info

Publication number: WO2006122935A1
Application number: PCT/EP2006/062347
Authority: WO
Inventors: Maurizio Frati
Original assignee: L'Air Liquide Société Anonyme pour l'Etude et l'Exploitation des Procédés Georges Claude; Air Liquide Italia S.P.A.
Priority date: 2005-05-20
Filing date: 2006-05-16
Publication date: 2006-11-23
Also published as: ITMI20050923A1

Abstract

Method for at least partly removing the dissolved oxygen in a liquid contained in a fluid agglomerate such as, in particular, mechanically harvested grapes or pressed grapes placed in a tank or container (1) in which the liquid is separated from the fluid agglomerate in a lower part (IB) of the said container (1). Provision is made for the introduction of a fluid which is capable of removing the oxygen present from that liquid or agglomerate, and possibly to cool that liquid or agglomerate, the said introduction of that removal fluid taking place directly within that liquid. A plant for implementing the above mentioned method is also claimed.

Description

METHOD AND PLANT FOR REMOVING DISSOLVED OXYGEN AND/OR COOLING LIQUIDS OR FLUID AGGLOMERATES THROUGH THE USE OF GASES OR LIQUEFIED GASES

This invention relates to a method for at least removing dissolved oxygen and forming and maintaining a protective atmosphere and preferably also cooling fluid agglomerates through the use of gases in accordance with the precharacterising clause of the principal claim. A plant for implementing the abovementioned method consistent with the precharacterising clause of the corresponding independent claim is also an object of the invention.

In this text the term "fluid agglomerate" is used to refer to grapes harvested by mechanical means and pressed grapes, the latter obtained by pressing grapes using the normal well-known systems, without thereby detracting from the general nature of the invention. This term may however also be used to identify any liquid element containing solid particles such as for example foodstuff juices or the like.

As is known, mechanical grape harvesting is carried out by mobile machines which harvest the grapes through mechanical action on the vines, thus bringing about good hourly productivity and a considerable reduction in costs in comparison with the times and costs of manual harvesting. The product which is obtained from mechanical grape harvesting may be regarded as a fluid agglomerate comprising a liquid component, known as must, and a paste-like component comprising partly crushed and broken grapes . The abovementioned material or agglomerate will for the sake of convenience be referred to as "harvest" below. Usually the must content constitutes 10 to 50% of the harvest by weight, this percentage depending on the different types of grape and the manner in which the harvesting machines operate .

The use of mechanical means has the undoubted advantage of reducing harvesting costs, but against this there are disadvantages relating to the loss of quality in the harvest due to various factors, but above all the presence of dissolved oxygen in the must following contact between this and the air in the course of harvesting. In fact because of the temperatures which are usually encountered at harvest time the dissolved oxygen tends to oxidise some of the components present in the must within a time of the order of tens of minutes, degrading its potential for quality. In any event temperature alone, at suitable levels as are normally present at harvest time, gives rise to undesired reactions in the harvest within a period of a few hours .

For these reasons it is desirable to act to remove dissolved oxygen quickly immediately after harvesting, in addition to lowering the temperature of the harvest. This is also necessary because the time required for transporting the harvest from the vine to the cellar where subsequent processing takes place is often of the order of hours, more than sufficient time to cause substantial damage to the harvest.

All of these aspects place limitations on the use of mechanical harvesting and have the result that in order to produce high quality wines grapes still in many cases have to be harvested manually, with the consequence of long and costly harvesting times .

Similar considerations apply to pressed grapes, where these have to be transferred using movable equipment from the pressing section to the subsequent winemaking section. At the present time the harvest is transported using trucks provided with tanks to contain the harvest, constructed in a leaktight manner, and which may be protected by a cover at the top, in which loading takes place from above and unloading takes place through simple tipping.

The object of this invention is in general that of providing a method and plant for protecting a fluid agglomerate, in particular mechanically harvested grapes and pressed grapes, through removing the dissolved oxygen in its liquid component and in the entire fluid agglomerate, for example in must which is produced naturally during the harvesting of grapes by mechanical means, inserting this into a container, forming a protective atmosphere over the entire agglomerate or only above the liquid component, and lowering the temperature of the liquid product alone or that of all the fluid agglomerate.

Another object of this invention is to provide a method of the aforesaid type which can be implemented at the time when the grapes are harvested, at the vineyard, before the means used for transport of the harvest begins its trip, or on this on the route between the place of harvesting and that of reception, for example a cellar, or at the place of reception itself.

Another object is to provide a method and plant for implementing it whose use does not affect the means by which the grapes are harvested.

This and other objects which will be apparent to those skilled in the art are accomplished by a method and plant according to the appended claims .

According to the invention the substances used to remove dissolved oxygen from the harvest may be applied in the gaseous or liquid state and are mainly CO2, N₂, Ar and mixtures thereof. In this text, where reference is made to CO2, N₂ or Ar in the gaseous state, these will be referred to as gases, whereas when reference is made to them in their liquid state they will be referred to as cryogenic liquids .

The physical processes on which this invention are based are known and can be summarised as follows:

- a dissolved gas in a fluid can be removed through the so-called stripping phenomenon which takes place after a removal gas, which is different from that which has to be removed, has been introduced into the fluid, or through a removal gas, which is also a different gas, formed within it following contact between an evaporating liquid and the fluid in question under the condition that the evaporating liquid is evaporating under the temperature and pressure conditions present within the environment in which contact takes place,

- a fluid may be cooled following direct contact with an evaporating liquid under the temperature and pressure conditions present within the environment in which contact takes place.

Cooling with evaporating liquids such as liquefied gases through direct contact between these and the fluid which has to be cooled is a process which is in itself known, for example such as described in patent IT 1313938 by the same applicant.

All removal gases or removal liquids will be referred to as removal fluids .

Applying the above considerations to the case in question means that in order to reduce the temperature of the must by only a few ⁰C very much more cryogenic liquid is required than is necessary in order to remove the oxygen. By way of example, in order to achieve satisfactory removal of the dissolved oxygen in must a quantity of cryogenic liquid which produces a volume of gas equal to 3 - 10 times the volume of the must which has to be treated will be required, depending on the system used for its distribution. In cases where CO2 in the liquid phase is used as the cryogenic removal fluid, these quantities are sufficient to reduce the temperature of the must by an amount of between 0.5 and 1.6⁰C. When N2 in the liquid phase is used as the cryogenic fluid the temperature decrease is even less.

It follows from the above that if it is only required to remove dissolved oxygen the consequent cooling obtained by removing the oxygen through cryogenic fluids is negligible; this means that in the case where the intention is cooling, the removal of oxygen takes place.

For a better understanding of this invention there are appended hereto purely by way of a non-restrictive example the following drawings in which:

Figure 1 shows diagrammatically a plant according to the invention in its complete form, suitable for both removing dissolved oxygen and cooling the must or, if necessary, the entire harvest,

Figure 2 shows a part of the plant in Figure 1 used to remove dissolved oxygen and cool the must only,

Figures 3A and 3B show transverse cross-sections of part of the plant in Figure 1 in two different embodiments ,

Figure 4 shows a different part of the plant in Figure 1 in longitudinal cross-section, and

Figure 5 shows a variant of the invention in which the cooling capacity produced by conventional mechanical systems is used solely for the purpose of cooling and heat exchange takes place in components such as a heat exchanger (40), a component which is in itself known.

With reference to the figures mentioned, the plant according to the invention comprises a tank or container to contain harvest 1 which in one embodiment comprises grapes harvested by mechanical means. Tank or container 1 is anchored to a supporting structure, or flatbed, 13 (which is for example mobile and/or motorised) and is provided with a movable cover system 2 with a corresponding opening 3 capable of acting as a gas vent valve, a discharge door 4 and a grid 5 for drainage of the liquid (must) present in the harvest which separates out and percolates to a lower part IB of container 1. Grid 5 in fact separates the tank into two parts, IA and IB (upper and lower) , in which the drained pasty mass lies in part IA and the must in part IB.

Where the invention is also used for cooling, tank 1 is suitably lagged by systems which are in themselves known .

Parts IA and IB also communicate with each other in addition to via grid 5 through a conduit 50 which may be provided with a one-way flow valve 51 operated by suitable means .

When grid 5 is completely covered by the pasty mass or obstructed, components 50 and 51 have the purpose of providing a free connection for the passage of gas from part IB to part IA, overcoming the pressure in part IB at the tare value for component 51, as will be more particularly described below.

At least one tubular injection member for gases or liquids 6, known as the injection lance, provided with passage holes 7 and a protective sheath 8, is inserted into tank 1. This member is illustrated in greater detail in Figures 4 in which it will be seen that sheath 8 is integral with tank 1 through a flanged or threaded connection. Lance 6 is provided with a component 10 which projects radially from the lance and which has the function of permitting manual rotation (or also motorised rotation through a suitable connection between that component 10 and a drive, for example an electrical drive) of the lance in the sheath about a longitudinal axis W, to permit holes 7, 7T to line up with holes 9 and 9T constructed in the sheath in order to allow the passage of gas or cryogenic liquid from injection lance 6 to the must present in tank 1. This gas or cryogenic liquid derives from a corresponding suitable tank or storage component which will be described below and which operates at least as a fluid for removing oxygen from the must. The relative rotation between lance 6 and sheath 8 may also be achieved through moving the latter and fixing the lance to tank 1.

Lance 6 is provided with sealing means 100, of the 0- ring type, designed to prevent the must from penetrating the gap between the lance and the sheath, giving rise to possible jamming of the lance in rotation because of the sugary substances present in the must which in the absence of this 0-ring arrangement might enter between it and the sheath.

The longitudinal seal of lance 6 in relation to sheath 8 is ensured through a bush 101 which permits 6 to rotate with respect to 8, but not to move relatively along the W axis.

In Figure 4, A indicates the inlet for gas or cryogenic liquid into lance 6. This gas or cryogenic liquid flows into the lance as far as holes 7 and from these, if they are aligned with holes 9, penetrates the must present in part IB of tank or container 1. The effectiveness of this invention is due to the fact that the gas or cryogenic liquid leaving lance 6 mixes the must and passes through it, remaining in contact with it for a sufficient time for the removal of dissolved oxygen; in addition to this it also forms a protective atmosphere against atmospheric oxygen, either between the must in grid 5, or between the drained pasty mass located above grid 5 and cover 2 of tank 1, and in the case where cryogenic liquid is used exchanges the heat necessary for cooling.

In the absence of cover 2 the protective atmosphere will only be present in part IB, the drained pasty mass acting as the cover member for this part.

Returning to tank or container 1, there are present within it components which are in themselves known such as a component 13, or temperature sensor, for measuring the temperature in must 11 in drained pasty mass 70 present in part IA of the tank, a component 11, or temperature sensor, for measuring the temperature of the must present in part IB, a component 12, in itself known, for measuring the level of the must present in part IB of tank or container 1, a component 19, in itself known, for measuring the dissolved oxygen present in the must located in part IB of tank 1, and a component 19A, in itself known, for measuring the oxygen present in the atmosphere within part IA of the tank.

Tank 1 is associated with a system for sampling and recycling the must comprising a collection tank 14 connected to tank 1 and connected through a suction pipe 15 to a pump 16 from which there departs a delivery line 17 terminating in a distributor/spray for must 18 located above drained pasty mass 70. A system or component for storing and delivering gas 20 is located alongside tank 1 and is connected to a delivery line 22, with a stop valve 21, and provided with a pressure-reducing and regulating system 23, a component which it in itself known, a flow measurement device 24 and a non-return valve 25. Line 22 is connected to a pipe 36 fitted with a purge valve 37

(opening into the environment) and connected to lance 6 through a flexible pipe 38. The latter allows lance 6 to rotate with respect to sheath 8. A component or system for the storage and delivery of cryogenic liquid 30 connected to a pipe 32 fitted with a stop valve 31 and a regulator valve 34 and a flow measuring device 35 is also present. Pipe 32 is connected to pipe 36 described above.

Tank 1 and components or systems 20 and 30 are provided with the usual safety components, which are not indicated in the figures .

Where the invention is applied to pressed grapes, a mobile tank suitable for the transport of fluids of this type may be used as containment tank 1.

Figure 3A illustrates an embodiment in which injection lance 6 and sheath 8 lie within containment tank 1, while Figure 3B illustrates the situation where injection lance 6 is outside the latter. In the latter case tank 1 will have holes corresponding to holes 9 of the sheath and in addition to this the sheath and the lance will not have end holes 7T and 9T (as illustrated in Figure 4) which open into part IB of tank 1 in the arrangement in Figures 1, 2 and 3A.

In Figures 3A and 3B a tank 1 having a lower part of reduced cross-section, of trapezoidal shape, the purpose of which is to permit a sufficient depth of must within it to cause easy removal of the oxygen and cooling even in the situation where the must is present in the harvest in a very small percentage, is shown by way of illustration, but not restrictively .

For a better understanding of this invention, the operating means for implementing the procedure to which it relates will be illustrated.

Three ways of implementing the invention associated with three different aims, all with reference to the said Figures 1, 2, 3 and 4 will be described below. The abovementioned methods are:

1 - removal of the oxygen dissolved in the must,

2 - removal of the dissolved oxygen and cooling of the must, and 3 - removal of the oxygen dissolved in the must, cooling of the must and of the pasty mass.

The operations which have to be performed and are common to all the embodiments of the invention are provision of the plant and loading of the harvest into tank 1. These are carried out through the following procedures :

Gl - The invention is implemented by positioning lance 6 by rotation in such a way that holes 7 and 9, and, if present, 7T and 9T described above are not opposite each other. This is done to prevent must from entering within injection lance 6 when gas or liquid is not flowing from it.

G2 - The harvest is loaded into tank 1, from which cover 2 has been removed, from above. Through drainage grid 5 must percolates into the lower part IB of the tank, while the remaining part, indicated as drained pasty component 70, is retained in the upper part IA of the tank.

G3 - When filling of tank 1 is complete, the latter is covered by movable cover 2. This and all the other specific procedures for achieving the specified aims may also be carried out automatically using components and systems which are in themselves known.

The above operations must necessarily be carried out while the tank is stationary, while the subsequent operations may be performed with the tank either stationary or in motion; in particular, these operations are performed

- necessarily with tank 1 stationary if the system for the storage of gas 20 and/or cryogenic liquid 30 and/or the must recycling system, in the case of cooling, are not mounted on flatbed 13 but are located on the ground,

- necessarily with tank 1 stationary if, although all the components involved are mounted on flatbed 13, the operations which have to be carried out are manual or are delegated to the operator,

- with tank 1 stationary or with tank 1 in motion if all the components involved are mounted on flatbed 13 and the operations which have to be performed are delegated to an automatic system.

In the example, the latter arrangement will be regarded as an example of an embodiment of the invention. It will also be considered that after the grapes have been loaded tanks 1 will be set in motion to reach the place of reception, for example a cellar.

1 - Removal of dissolved oxygen

As already described previously, for sufficient removal of the dissolved oxygen it is considered that a volume of gas equal to approximately 3-10 times the volume of the must which is to be treated will be required and that this quantity must be delivered preferably within a time period not exceeding 10-15 minutes. Given that shorter times result in less degradation of the must, it is preferable that the operation should be completed in the least time possible compatible with both the characteristics of system 20 or 30 for the delivery of gas or cryogenic liquid and the characteristics of injection lance 6. Thus by setting the delivery time and the quantity which has to be delivered, the hourly- throughput which has to be provided will be determined.

All and only the components which are used to remove dissolved oxygen are illustrated in Figure 2, to which reference is made in the following description.

1.A - The case in which gas is used

In the case in question the following procedures are used: l.A.l - Valve 21 is opened and the pressure of the gas is adjusted by acting on reducer 23, setting it for example to approximately 0.5 - 0.8 bar,

1.A.2 - Lance 6 is rotated so that holes 7 and 9 are opposite each other,

1.A.3 - The flow of gas is adjusted by acting on reducer 23 and checking it using measuring device 24, 1.A.4 - Tank 1 may now be set in motion.

1.A.5 - The end of the operation of removing oxygen is determined in one of the following two ways :

- after a predetermined time for the delivery of gas has elapsed, or - when component 19 which measures the quantity of dissolved oxygen indicates a desired value.

Once the operation has been completed, if tank 1 has not yet completed its journey the throughput can be reduced by acting on reducer 23 or by wholly shutting off the delivery of gas, this being affected by rotating lance 6 in such a way that holes 7 and 9 are not opposite each other, and subsequently closing valve 21. Delivery of the gas by the means described above, including during transport, regardless of whether the operation of removing dissolved oxygen is complete, makes it possible to limit, or eliminate for protective purposes, any oxygen which may be present in the air which might penetrate within tank 1 through cover 2 in the course of the abovementioned movement.

l.A. The operations cease, after closing valve 21 and rotating lance 6 in such a way that holes 7 and 9 are not opposite each other, and closing valve 21 draining pipes 23, 35 and 36 through opening valve 37.

A variant of the invention is that what is illustrated may also be applied directly on the harvesting machine, specifically in the containers thereof containing the harvest. Also, through applying this variant, complete protection of the harvest in relation to oxygen is obtained, the protection being extended to the entire period of time between detachment of the grape from the bunch to its receipt at the cellar for subsequent processing.

l.B. The case in which cryogenic fluid is used.

This method is similar to the previous method: the difference lies in the fact that when a cryogenic liquid is used the components of the plant which have to be used are 30, 31, 32, 34 and 35 instead of 20, 21, 22, 23, 24 and 25.

In this case there is a choice of the method which must be used to regulate the quantity of cryogenic liquid delivered. In fact flow regulation through regulating valves is feasible with fluids in the liquid state such as N₂ and Ar, but it is difficult with liquid CO₂ because of its thermodynamic characteristic of existing in the solid phase and the gaseous phase at pressures below 6 bars, as a result of which, in the case of the invention, it is possible for there to be solid phase downstream from the regulator valve with probable obstruction of the line and malfunctioning of the system. Thus when liquid CO2 is used the most effective solution is to use holes 7 of lance 6 as flow regulators, these being constructed with suitable dimensions to permit a defined flow of cryogenic fluid. These holes in practice ensure an almost constant flow, causing control of the quantity which has to be delivered to lie with the time for which valves 31 and 34 are opened.

The holes produced as above constitute regulator valve 34, which may be removed or replaced by one of the on- off type.

The above solution may also be applied in the case where N₂ and Ar are used as cryogenic fluids .

Operating procedures

l.B.l - Valve 31 is opened, 34 is set, if installed, and liquid CO₂ is not being used as the cryogenic fluid, lance 6 is rotated to place holes 7 and 9 in communication .

When working with liquid CO2 valve 34, if fitted, is opened completely.

1.B.2 - Tank 1 can then be set in motion. 1.B.3 - The end of the operation of removing oxygen is determined in one of the following ways, in a similar way to that seen in the case where gas is used:

- after the predetermined time for the delivery of cryogenic fluid has elapsed, or - when component 19 measuring dissolved oxygen 19 indicates the desired value.

Once the end of the operation has been reached the operator (or the unit for automatic command and control of the plant through action on a suitable actuator) causes lance 6 to rotate in such a way that holes 7 and 9 are not in line.

1.B.3 - Valve 31 is closed, the contents of lines 32, 36 and 38 are discharged to the air by opening valve 37.

Once the contents have been discharged valves 34, if fitted, and 37 are closed. 1.B.4 - In this case, as in the previous case, provision may be made for the delivery of cryogenic liquid to tank 1 in reduced quantities while the harvest is being transported. This can be done either by regulating the flow of cryogenic liquid through valve 34 and controlling it through measuring device 35, if N₂ or Ar are used, or by leaving the flow unchanged but limiting the delivery time by alternating the delivery and stop stages through an appropriate delay, necessarily if CO₂ is used, and optionally if N₂ or Ar are used.

When the criterion of limiting delivery time is used, in the course of the pause to prevent must from penetrating within the lance when the latter is not delivering cryogenic liquid the lance must be rotated to bring holes 7 and 9 out of alignment.

During these operations valves 31 and 34, if the latter is present, may remain open.

2. - Removal of dissolved oxygen and cooling of the must .

This procedure operates in a similar way to that described in preceding case IB. Again in this case the components of the invention which have to be used for this purpose are the same as in the previous case, and are all those indicated in Figure 2 with the exception of 20, 21, 22, 23, 24 and 25. The quantity of cooling fluid (cryogenic liquid) which has to be delivered may be controlled and managed either via regulating valve 34, in the same way as seen previously if the thermodynamic characteristics of the cryogenic fluid permit it, as in the case of N2 or Ar, or by causing holes 7, which have been adequately dimensioned, to act as flow regulators.

In both cases the delivery of cryogenic liquid ceases either when the previously specified quantity has been delivered or when the desired temperature in the must has been reached, a temperature which is measured by one or more thermometer sensors 11.

When the method of ceasing delivery after the delivery of a predetermined quantity is used, it is superfluous to fit thermometer sensor 11.

The specific operations which have to be performed are illustrated below, to clarify what has been described.

2.1 - Valves 31 and 34 are opened and lance 6 is rotated until holes 7 and 9 are no longer in line.

This operation allows the cryogenic fluid to penetrate the must, mixing it, deoxygenating it and cooling it.

2.2 - When the desired temperature has been reached, as indicated by sensor 11, or after the specified time for delivery of the cryogenic liquid has elapsed, lance 6 is rotated until holes 7 and 9 cease to be opposite each other.

2.3 - Valve 31 is closed, purge valve 37 is opened, the cryogenic liquid present in lines 32, 36 and 38 is allowed to escape, and then 34 and subsequently 37 are closed. The operation of cooling the must to the desired temperature is now complete and as a consequence the dissolved oxygen has been removed.

Following the above operations the drained pasty mass may be subjected to slightly non-uniform cooling through contact with the gas produced by the cryogenic fluid passing through it following its passage from pipe 50 and possibly grid 5.

2.4 - Again in this case cryogenic fluid can be delivered while the tank is in motion, as described in paragraph l.B.4.

3. - Removal of dissolved oxygen, cooling of the must and the pasty mass

The components of the invention which must be used for this purpose are those indicated in Figure 1, to which reference will be made in the following description.

Some of the parameters and their logical correlations with the fitted components involved, such as valves 31 and 34, pump 16 and temperature measuring devices 11 and 13 and level measuring device 12, will be indicated for easy understanding of the description.

Parameters

- Tm: temperature of the must detected by component or sensor 11. - Tsm: preset value and corresponding interval (Tms+t, Tsm-t) for the temperature Tm of the must.

- Lm: level of the must indicated by component or sensor 12.

- Lsm: preset value with corresponding interval (Lsm+1, Lsm-1) with reference to the level of the must.

Tp: temperature of the pasty mass indicated by component or sensor 13.

- Tsp: preset value with corresponding interval (Tsp+t, Tsp-t) with reference to the temperature of the pasty mass .

- Lsp: preset temperature with corresponding interval (Lsp+1, Lsp-1) with reference to the level of the must. Tm, Tsm with its interval (Tsm+t, Tsm-t) , Lm, Lsm with its interval (Lsm+1, Lsm-1) are correlated with the opening of valves 31 and 34 (if the latter is fitted) which hold back the delivery of cryogenic liquid to the must. The correlation is performed with a logic which will be described in the operating procedures below.

Tp, Tm, Lsp with its interval (Lsp+1, Lsp-1) are correlated with pump 16 being switched on and off with a logic which will be described below.

A necessary condition for permitting cooling of the pasty mass through this invention is that its required temperature, Tsp with its corresponding interval, should be greater than or equal to the required temperature of the must, Tsm, with its corresponding interval, so as to render heat exchange through the absorption of heat from the pasty mass by the must possible .

Logical correlations between Tp, Tsp, Tm, Tsm, Lm, Lsm, Lp, Lsp, valves 31 and 34 and pump 16.

What follows are possible correlations illustrated by way of a non-restrictive example of possible operation.

- CLl - correlations with valves 31 and 34 (if installed) :

- opened when Lm > (or equal to) (Lsm+1) and Tm > (Tsm+t)

- closed when Lm < (Lsm-1) or Tm < (Tsm-t)

- if (Lsm-1) < (or is equal to) Lm < (or is equal to) (Lsm+1) or (Tsm-t) (or is equal to) < Tm < (or is equal to) (Tsm+t) they remain open if they were open when these conditions occurred, they remain closed if they were closed at the time when these conditions occurred.

This logic makes it possible to cool the must to the desired temperature if one aspect of it is sufficient for effective heat exchange between the cryogenic liquid and the must.

- CL2 - correlations with pump 16: - switched on if Tm < (Tsp-t) and

Lm > (Lsp+1) and Tp > (Tsp+t)

- switched off if Tm > (Tsp+t) or Lm < (Lsp-1) or Tp < (Tsp-t)

- if: (Tsp-t) < (or equal to) Tp < (or equal to) (Tsp+t) or (Lsp-1) < (or equal to) Lm < (or equal to)

(Lsp+1) or (Tsp-t) < (or equal to) Tm < (or equal to) (Tsp+t) , pump 16 remains on if it was on at the time when these conditions occurred, it remains off if it was off at the time when these conditions occurred.

This logic makes it possible to deliver the cooled must to pasty mass 70 only if this has a temperature suitable for heat exchange and if the level of must in collection tank 14 is sufficient to cause pump 16 to operate correctly.

The operating procedures are as follows :

3.1 - Valve 21 is opened and pressure reducer 23 is set to values around 0.5 - 1 bar or in any event to values such as to cause gas to flow through holes 7, 7T when these are opposite holes 9, 9T as in the subsequent operating procedure (3.2) .

3.2 - Lance 6 is rotated so that holes 7, 7T and 9, 9T are not opposite each other,

3.3 - The operations as described in the previous logical correlations CLl and CL2 are carried out.

In the course of the repetition of CLl and CL2 described, valves 31 and/or 34 may open and close repeatedly. When they are closed, even if valve holes 7 and 9 are opposite each other, must does not penetrate within the lance because gas is passing through the latter as a result of the position of valve 21 and reducer 23 as specified in section 3.1 above. Stage 3.3 makes it possible to spray the pasty mass with cold must and consequently to cool it to desired temperature values, Tsp.

3.4 - The operations associated with logical correlations CLl and CL2 terminate when Tp lies within the range for which it has been set, (Tsp+t, Tsp-t) and Tm lies within the interval for which it has been set, Tsm+t, Tsm-t.

The above indicates that both the must and the pasty mass have reached the required temperatures.

3.5 - Lance 6 is rotated until holes 7 and 9 cease to be opposite each other.

3.6 - Valve 21 is closed and 37 is opened, discharging the gas present in lines 36 and 38 to the air, valve 37 is closed.

Now tank 1 contains must from which the previously dissolved oxygen has been removed and cooled must and pasty mass, all protected by an atmosphere containing at the most negligible levels of oxygen.

If it is desired to continue with protection of the harvest even after the required temperature has been reached, such as for example in the case of a long trip with the risk of introducing excessive quantities of air into the truck through cover 2, the previous stages 3.5 and 3.6 are not activated and are only activated when it is desired to cease this form of protection.

In all three ways of implementing this invention described previously, where the flows of fluid for the removal of gas or cryogenic liquid required to perform what has been described are very high, such as to require a delivery system having dimensions which make it impossible to locate it integrally with the truck, the operations of delivering this removal fluid described above will be carried out with the truck stationary, drawing the fluid from a static delivery system (removably connectable to lance 6) , located on the ground, and using a storage system located on the truck to deliver only the fluid (gas or cryogenic liquid) necessary during movement of the truck for the sole purpose of maintaining the protective atmosphere.

Various ways of implementing the invention have been described. Yet others are however possible in the light of the above description and must be regarded as falling within the scope of this document.

A first variant of what has been described previously comprises delivering, solely for the purposes of cooling, cryogenic fluid to part IA above pasty mass 70, this cryogenic fluid cooling the pasty mass with which it comes into contact, which in turn cools the must, sprayed through components 15, 16, 17 and 18, which in turn cools the pasty mass completely by percolating through it.

A second variant of what has been described above is the situation in which the fluid agglomerate has a degree of fluidity such that sufficient mixing of it for proper conduct of the process for reducing the oxygen content and heat exchange can be brought about only following injection of the gas or cryogenic fluid.

In this case it is not necessary that tank 1 should be provided with a separating grid 5 and consequently preceding parts IA and IB are not formed and gas or cryogenic fluid is delivered into the fluid agglomerate which is not separated into its components.

A further variant, which is possible only for the purposes of cooling the must and, possibly, the pasty mass, relates to heat exchange not with cryogenic fluids but through cooling produced by conventional mechanical systems, systems which are in themselves known. This further variant is illustrated in Figure 5. In this 40 indicates the heat exchanger, for example of the tube in tube type, but without thereby detracting from generality; 41 indicates the cooling fluid line originating from a cooling plant operating through mechanical and electrical systems which are in themselves known; 42 indicates the cooling fluid returning to the mechanical refrigeration plant, plant which is not indicated in the figure. In the figures in question, parts corresponding to those in the figures already described are indicated by the same numerical references. The variant cited consists of cooling the must through mechanical cooling and by means of a heat exchanger, a component which is in itself known, and preceding as described previously to spray the pasty mass with cold must.

Obviously in this case the logical connections between the temperatures and the components of the plant will change, a change due to the fact that cooling of the must no longer takes place in tank 1 but in a suitable component 40, controlled and operated by systems which are in themselves known. These changes may however easily be made by those skilled in the art on the basis of what has already been described and will not therefore be more particularly mentioned.

Various embodiments of the invention have been described. Yet others are however possible in the light of the foregoing description and are to be regarded as falling within the scope of this document.

Claims

1. Method for at least partly removing the oxygen dissolved in a liquid or fluid agglomerate, in particular grapes which have been harvested using mechanical systems or crushed grapes produced by systems in themselves known, placed within a tank or container (1) in which the liquid is separated from the fluid agglomerate, a liquid which percolates into a lower part (IB) of the said container (1) and in which the drained fluid agglomerate, or pasty mass, remains in the upper part (IA) , characterised in that provision is made for the introduction of a fluid capable of removing the oxygen present from that liquid, the said introduction of that removal fluid taking place directly within that liquid.

2. Method according to claim 1, characterised in that the removal fluid is selected from CO2, N2, Ar or mixtures thereof.

3. Method according to claim 2, characterised in that the removal fluid is in the gaseous state.

4. Method according to claim 2, characterised in that the removal fluid is in the liquid state.

5. Method according to claim 1, characterised in that the removal fluid if in the liquid state cools the liquid into which it is introduced directly.

6. Method according to claim 5, characterised in that the cooled liquid present in the lower part (IB) of the tank or container (1) is drawn from that part (IB) and delivered to an upper part (IA) of that tank (1) such as to spray the pasty mass present in the latter and cool it.

7. Method according to claim 6, characterised in that provision is made for delivering a removal fluid in the gas phase into the tank or container (1) and subsequently also into the liquid phase in order to cool the liquid and create a protective atmosphere within that tank or container (1) .

8. Method according to claim 6, characterised in that the liquid present in the lower part (IB) is drawn therefrom and cooled outside the tank (1) before being delivered to the upper part (IA) of the said tank (1) in order to spray and cool the pasty mass (70) present therein.

9. Method according to claim 1, characterised in that the temperature of the pasty mass and the liquid is monitored while the cooling fluid is introduced into it.

10. Method according to claim 1, characterised in that the quantity of dissolved oxygen in the liquid is monitored in order to control the delivery of removal fluid into it and to stop that delivery when a predetermined quantity of dissolved oxygen is reached.

11. Method according to claim 1, characterised in that a volume of removal fluid which is at least equal to or greater than three times the volume of the liquid present in the tank or container (1) is delivered.

12. Method according to claim 1, characterised in that the delivery of removal fluid into the liquid takes place within a period of time of less than 15 minutes.

13. Method according to claim 1, characterised in that the removal fluid is delivered into the liquid or fluid agglomerate immediately after the grapes have been harvested on the machine designed for mechanical harvesting.

14. Method according to claim 11, characterised in that the removal fluid is delivered into the liquid or fluid agglomerate while the said tank or container (1) is in motion from the place where the grapes are harvested to a place of reception such as a cellar.

15. Method according to claim 11, characterised in that the said removal fluid is delivered into the liquid or fluid agglomerate discretely at specified time intervals during the journey from the place at which the grapes are harvested to the place of reception.

16. Method according to claim 11, characterised in that the removal fluid is delivered into the liquid or fluid agglomerate at a constant flow.

17. Method according to claim 11, characterised in that the removal fluid is delivered into the liquid or liquid agglomerate for a predetermined time.

18. Plant for implementing the method in claim 1, the said plant comprising a tank or container (1) into which the fluid agglomerate, in particular mechanically harvested grapes, is placed, the said tank or container

(1) , which may be lagged, having a lower part (IB) in which a liquid naturally collects beneath a pasty component present in an upper part (IA) of that tank

(1) , characterised in that injector means (6) are provided in the lower part (IB) of the tank for the introduction of a removal fluid which is capable of at least partly removing the desorbed oxygen within the liquid directly into the liquid in which those injector means (6) are immersed.

19. Plant according to claim 18, characterised in that the said injector means are at least one tubular injection member (6) connected to at least one source (20, 30) of a feed of the said removal fluid, the said tubular member (6) being provided with passage holes (7, 7T) opening into the lower part (IB) of the tank (D •

20. Plant according to claim 19, characterised in that the tubular injection member (6) is inserted into a tubular sheath (8) , the said member and sheath being able to rotate relative to each other about a common longitudinal axis (W), the said sheath having holes (9, 9T) capable of being located in the position corresponding to those of the holes (7, 7T) in the tubular member (6) at least when the removal fluid is delivered into the liquid or fluid agglomerate.

21. Plant according to claim 20, characterised in that the tubular sheath (8) is fixed to the tank or container (1), the tubular injection member (6) being connected to a pipe (36) for delivery of the removal fluid to the aforesaid tank.

22. Plant according to claim 20, characterised in that sealing members (100) are present between the tubular sheath (8) and the injection member (6) in order to prevent the liquid or fluid agglomerate from entering between the said member and the sheath, preventing relative movement.

23. Plant according to claim 20, characterised in that sealing members (101) are present between the tubular sheath (8) and the injection member (6) to prevent relative movement between the tubular sheath (8) and the injection member (6) along the longitudinal axis (W) .

24. Plant according to claim 20, characterised in that the tubular member (6) has a component (10) projecting radially from the tubular injection member (6) outside the tank or container (1) , action on the said component (10) making it possible to rotate the injection member (6) about the longitudinal axis (W) .

25. Plant according to claim 24, characterised in that the component (10) of the lance acts together with an electrical actuator in order to rotate the injection member (6) .

26. Plant according to claim 21, characterised in that the tubular injection member (6) is connected to the pipe (36) delivering removal fluid via a flexible pipe (38) capable of permitting movement of that member (6) relative to the sheath (8) .

27. Plant according to claim 21, characterised in that the pipe (36) for the delivery of removal fluid is connected to at least one delivery line (22, 32) for that fluid connected to a corresponding tank (20, 30) , a corresponding flow measurement device (24, 35), a stop valve (21, 31) and flow regulating means (23, 34) being located on that delivery line.

28. Plant according to claim 27, characterised in that the said tank (20) of the said delivery line (22) contains a removal fluid in the gaseous state.

29. Plant according to claim 27, characterised in that the said tank (30) of the said delivery line (32) contains a removal fluid in the liquid state.

30. Plant according to claim 21, characterised in that the pipe (36) connected to the injection member (6) is connected to two delivery lines for removal fluid (22, 32), a first line (22) ending in a tank (20) in which that fluid is in the gaseous state and the second line (32) ending at a tank in which that fluid is in the liquid state, one (22) of those lines (22, 32) having a non-return valve (25) .

31. Plant according to claim 21, characterised in that the said delivery tube (36) is fitted with a purge valve (37) .

32. Plant according to claims 18 and 21, characterised in that the tank or container (1) containing the liquid and the fluid agglomerate is movable and is associated with a loadbearing member (13) which also supports the pipe (36) and at least one delivery line (22, 32) for the removal fluid with the corresponding tank (20, 30) .

33. Plant according to claims 18 and 21, characterised in that the tank or container (1) containing the liquid or fluid agglomerate is supported by a movable loadbearing member (13) , the pipe (36) and each delivery line (22, 32) for the removal fluid with the corresponding tank (20, 30) being separate from that loadbearing member and being fixed, that pipe (36) being attachable in a removable way to the injection member (6) through a removable connection.

34. Plant according to claim 18, characterised in that the tank or container (1) containing the liquid or fluid agglomerate is fixed.

35. Plant according to claim 18, characterised in that the removal fluid is selected from CO2, N2, Ar and mixtures thereof.

36. Plant according to claim 35, characterised in that it comprises means for obtaining gaseous N2 from the air.

37. Plant according to claim 18, characterised in that the two parts, the upper part (IA) and the lower part (IB) of the tank or container (1) are separated by a grid (5) .

38. Plant according to claim 18, characterised in that the two parts, the upper part (IA) and the lower part (IB) of the tank or container (1) are connected together through a connection (40) fitted with a one- way valve (41) , a connection suitable for allowing gas to flow from part IB to part IA.

39. Plant according to claim 18, characterised in that detector and/or measuring means (11, 12, 19, 19A) for the temperature of the liquid or fluid agglomerate, the pasty mass, the level of the liquid, the quantity of dissolved oxygen in that liquid or fluid agglomerate, the oxygen present in the free internal atmosphere of the truck or container (1) abovementioned, are provided within the tank or container (1) in both part IA and part IB.

40. Plant according to claim 18, characterised in that it comprises sampling and recirculation means (15, 16, 17, 18) for sampling the liquid into which the removal fluid has been delivered and carrying it above the pasty mass above the said liquid within the tank or container (1), this recirculation permitting cooling of that pasty mass and the formation of a protective atmosphere above it.

41. Plant according to claim 40, characterised in that the sampling and recirculation means comprise a suction pipe (15) connected to a pump (16) from which there departs a delivery line (17) terminating in a distributor/spray (18) for that liquid onto the pasty mass .

42. Plant according to claim 18, characterised in that the tank or container (1) is devoid of internal separation members, as a result of which there is a single undistinguished mass of fluid agglomerate within the tank (1) .

43. Plant according to claim 18, characterised in that the tank or container (1) is without a movable cover.

44. Plant according to claim 18, characterised in that the tank or container (1) is lagged to thermally insulate its contents .

45. Plant according to claim 18, characterised in that the tank or container (1) comprises a reservoir equipped with suitable means for entry and departure of the fluid agglomerate and the removal and/or cooling fluids .