LU85954A1 - ASEPTIC STORAGE SYSTEM FOR FERMENTED LIQUIDS IN FLEXIBLE TANKS - Google Patents

Description

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The present invention relates to an aseptic buffer storage system for liquid products which may or may not contain fermentable particles and the associated devices enabling it to operate, the tanks being able to be fixed or mobile.

The storage tanks consist of flexible flexible envelopes, of any general shape but above all cylindrical 'and terminated by hemispherical or other sections, immersed in a liquid which may be water in which one has, or has not, been dissolved or dispersed salts in order to adjust the density or to give it desirable properties.

The entire system is sterilized before being put into service and, except in the event of an accident, should no longer be sterilized during its life, provided that the products are themselves perfectly sterilized by known methods before entering the system and that. withdrawals of sterilized products stored are carried out without the sterility of the interior of these tanks ceasing to be total.

The use of flexible magazine tanks makes it possible to avoid any movement of gas during the successive filling and emptying maneuvers.

25 Anyone skilled in the art knows how difficult and unsafe it is to sterilize large flows of gas. This problem is eliminated.

The immersion of the flexible tanks in a liquid leads to the following advantages: 30 - Reduction of the solicitations to which the envelope is subjected - Protection against voluntary depredations, or accidental, human or animal.

- Easy temperature control.

35 - Together with an adequate shape of the surface on which the store tank is placed, ensures a constant cuasi pressure, facilitating the emptying of stored liquids.

-: trust an automatic transfer ror.trs-r on? . -a devices st = ri-isc. '. t = t cooling the ·; - 2 - - Reduction or elimination of oxidation of stored products.

With regard to this oxidation, the membrane forming the wall of the flexible tanks will be chosen according to the requirements of the packaged product, the duration of the storage and also the duration separating the periods during which the tank contains appreciable quantities of liquid because in a flexible tank containing very little liquid, the ratio overrated) this / volume is very high, oxidation then being particularly to be feared.

Permeation, oxygen through the membrane and the outer liquid mattress is the only source of oxidation for the packaged product.

When it is important to reduce oxidation, the system which is the subject of the present invention reduces the oxygen content of the immersion liquid by implementing one or more of the following methods: 20 - Total or partial elimination, by physical, chemical or biological processes of the oxygen content of the immersion liquid.

- Protection or covering of the surface of the liquid suppressing or reducing the rate of dissolution of the gases in the immersion liquid.

- Replacement of the air on the surface of this liquid by an oxygen-depleted or oxygen-depleted gas.

The description of the invention is supplemented by examples. These only describe duplicating examples and do not constitute limitations to the general scope of the invention.

Example 1.

35 Arrangement ^ Storage capacity 3600 m3 - 12 flexible tanks with a unit capacity of 300 m3 - Diameter 5m - Length 2l m. -Hcutsur in the filled state (80%) 2.95 m. - Surface at • “y · or t Zs. Yyyy Z. 2Γ w · v r. uc c- "u. " *. ·. · - ___ · _ _ _ - Λ.

_ * 3 "in a square basin 47.5 m wide and 3.5 m high (7900 m3).

A central gallery located under the basin provides access to the connection ports of the 5 tanks.

In a variant, the flexible tank is placed in a "cell" whose axis is parallel to the axis of the tanks, the slope at the longitudinal edge of the cell directed towards the connection orifice is slightly greater than the natural flow slope of the packaged fluid (This is only exceptionally Newtonian). The basin is covered with a roof lined with thermal insulation to reduce thermal losses if the storage is done at a temperature different from the ambient air temperature (Maximum 25 ° C for purees and concentrates tomatoes, 15 ° C, 10 ° C and even 5 ° C for delicate fruit juices).

20 The tank is equipped with a constant calf device if the individual variations in filling of the different tanks require it. If necessary, the basin is equipped with a cooling system and an agitation system which ensure constant temperature

Example 2.

Conditions identical to those of Example 1, but the basin is formed by embankment dikes whose sealing is ensured, if necessary, by a plastic membrane.

Example 3.

- Influence of the liquid filling the 300 m3 tank basin.

- Diameter = 5 m ”- Height when filled 35 (80%): 3 m.

- Density of the packaged liquid: 1.2 Kg./liter.

- Density of the fluid outside: 0 (a gas.

_ - r-.r iIn the tank membrane? - 4 - - If the density of the liquid outside is 1 Kg / liter, the tension in the membrane is 0.2 x 3002 x 1 _ 4.5 Kg / cm2.

4 1000 - if this density is 1.1, the vision drops to 5 0.1 x 3002 x 1_ _ 2.25 Kg / cm2.

4 1000 - If the density of the external liquid is close to that of the aseptically stored product, the height of the tank increases, so it must be mechanically limited to maintain complete immersion.

Example 4.

- Oxygen permeation to the liquid product packaged.

- The external liquid has an influence on the oxygen permeation rate. There is none on the oxygen content, at equilibrium, of the packaged product, unless the oxygen content of the external liquid is artificially reduced, either directly or indirectly by reducing the oxygen content of the atmosphere above the basin, or again by combining these two actions.

For the flexible tank of which question in example 1, with a membrane in high density polyethylene. Oxygen permeability:

O

25 3.2 cmJ / cm / day / atmosphere / m2.

Recall that the oxygen permeability of a layer of immobile water can be estimated at 3 3 2 10 cm / cm / day / atmosphere / m (immobile layer, initially not saturated with oxygen).

30 - Permeability of the membrane in high density polyethylene having a thickness of 0.2 cm: 3 3.2 x 0.2 _ 3.2 cm / day / m2.

0 * 2 - Permeability of a 50-year-old water layer: 3 3 10 x 0.2 _ 4 cm / day / m2 50 35 - permeability of the whole; t - 5 - - The influence of the water layer is theoretically appreciable.

- It is practically zero if the water is aerated and moving.

5 - On the other hand, we manage to suppress any transfer of oxygen to the sterile product if the external liquid, even agitated, does not contain oxygen.

’With a reduced permeability membrane, type 2 mm. of high density polyethylene and 0.01 mm of 10 CLARENE L. (Solvay) the permeability of the barrier product, the Clarene being: -4 3 6 x 10 cm / cm / day / atmosphere / m2.

That of the Clarene layer is 6 x 10 "^ x 103 x 0.2 = 0.12 cm3 / day / m ^.

15 and the permeability of the whole:? ° 372 + i + 0712 8 · 89 'Hence P = 0.112 cm3 / day / m2 The influence of the water and polyethylene layers is negligible.

3 20 - Recall that one cm of oxygen weighs I§4ÔÔ = 7 * 14 10 "Valves - The surface / volume ratio of the tank considered is approximately 1.1 when it is full.

When the tank is empty the layer of water to a thickness of at least 3 m. or at least six times t. more important.

With a pure polyethylene membrane we have: - + - = 1.81 where total permeability P 4 3 P = 0.552 cm / day / m.

30 - With a polyethylene and clarene membrane we have: F = 3 ^ 2 *! + tïî = from ° to 3 v, 2 P = 0.0986 cm of oxygenated / day / m.

As the surface / volume ratio increases much more than the improvement resulting from the increase in thickness of the water layer, the contents of the tank will oxidize more quickly.

- In practice; it is generally better to neglect the effect l: rr; .sft water and use a tank

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- 6 - only a sufficient impermeability to oxygen and to the flavors whereas it is advisable, in particular cases, to multiply the precautions by reducing the oxygen content of the immersion liquid.

5 Example 5.

Flexible tanks are mainly "· intended for intermediate storage of expensive fruit derivatives, highly sensitive to oxygen and heat, justifying a higher investment 10 than tomato derivatives.

We build several independent tanks, completely isolate them, refrigerate the sterilized products before storage and place a barrier against oxygen floating above the water, refrigerated, tanks.

Although this water is degassed, the air above the basins is replaced by a gas very poor in oxygen, the space concerned being gas tight. Thus the amount of oxygen entering the flexible tanks per day is close to zero.

The stability of the stored products is perfect, even in tanks containing only a negligible quantity of sterile product and sometimes having to wait more than a year before being loaded again.

25 Indeed, the necessary and sufficient conditions ensuring industrial perfect stability are met: sterility, low temperature and the absence of oxygen.

Claims (23)

1. In its simplest execution, it employs one or more rigid reservoirs or at least relatively stable shapes and dimensions, each containing one or more flexible reservoirs, sterilized before their placement or sterilized after this placing in place, each equipped so that it can be filled or emptied aseptically indefinitely, without the supply of sterile gas, thanks at least to aseptic piping and valve, sterile or sterilized, while the flexible capacity tank and any shapes, generally between 20 50 and 1000 m and cylindrical, is immersed in a liquid used to reduce the mechanical stresses of the flexible walls, to reduce or suppress the oxidation of the sterile liquid, to cool the latter or to maintain it constant the temperature, to exert a static pressure on this sterile liquid and finally to protect the flexible tank against voluntary or accidental depredations, human or year imales as well as against other external actions such as that of the sun's rays. 30 2) The external tanks containing the immersion liquid and the flexible tanks are made of concrete, masonry, metal, plastic or earth and dikes possibly made watertight thanks to a! plastic film. 35 3} The flexible tanks are made of plastic films or of elastomers, impermeable to microorganisms, whose permeability to water, to arcs and to xvcene is either low or practically zero, ”- δ - 4. The flexible tanks and the aseptic pipes and valves which are directly connected to them are sterilizable, by g * rays, by heat, by antiseptics or by combining these 5 means, the heat being supplied from the outside or from the inside and, in the latter case, by a liquid, a vapor or a mixture constituted by an incondensable gas, a hot mist of water or any other liquid and by a chemical rapidly destroying the microorganisms . 5. The hoses and / or aseptic valves of the flexible tanks are connected to them in any location, at the bottom, on the side or at the top, the possible hoses being rigid or deformable. 6. There are, per flexible tank, one or more aseptic pipes and / or valves for connection with the outside in order to be able to sterilize, rinse, fill and empty the tank, normal operations being limited to one succession of aseptic filling and emptying separated by durations during which the flexible tank is used for aseptic storage of sterile liquid products, the temperature of these as well as the quantities of oxygen which they absorb being adjusted with a view to '' maintain the qualities at the desired level for the required time. 7. The connections between the flexible tanks and the network of upstream and downstream connecting pipes are made so that the temperatures required for the thermal sterilization of these networks do not deteriorate the flexible tanks, this thanks to the choice of transmitting materials heat, or by means of a local cooling device for the piping connected to the flexible tank. 8. The immersion liquid is cooled or heated to cool the contents of the flexible tank or to prevent it from freezing. 40 9} The irirersicn liquid is isolated from bare air between this surface and the flexible tank. 10. The surface of the pool is protected by an enclosure, the walls of which are, or are not, insulated and gas-tight and whose access may be made impossible under normal working conditions. 11. The air in the enclosure located above the basin is replaced by a gas depleted in oxygen or devoid of oxygen. 10 12) The wall of the flexible tanks facing their emptying orifices is reinforced and equipped with external tensioners or cables limiting its movement, preventing it from blocking the orifice, stopping the withdrawal if necessary and acting on a degree indicator filling. 13. The wall of the flexible tanks acts on an indicator of degree of filling and on a safety device stopping the filling before it causes excessive tension in the membrane. 14. The immersion liquid is water or a mixture of water and dissolved or suspended salts increasing the density and / or absorbing oxygen and / or increasing the viscosity. 25 15) The oxygen content of the immersion liquid is lowered by physical means such as vacuum degassing or vacuum cooling. 16. The oxygen content of the immersion liquid is lowered by physical means such as intimate contact with a neutral gas. 17. The oxygen content of the immersion liquid is lowered by chemical means. 18. The oxygen content of the immersion liquid is lowered by a biological means using microorganisms or enzymes and an oxygen receptor. 19. The immersion liquid whose oxygen content is reduced or zero circulates you bottom up in the basins equipped with a plc plarr .. preventing * - GG - 20. The flexible tank is free in the immersion liquid. ! 21) The flexible tank is held laterally j * in the immersion liquid. ! 5 5 22) If the density of the immersion liquid is greater than that of the sterile liquid contained in the i | flexible tank, the latter is kept immersed by a net. 23. The walls of the rigid tank where there is j .10 contact with that of the flexible tank are provided with a suitable temperature conditioning device by circulation of the immersion liquid i or directly by conduction. I \ j i