DE2130996A1 - Transport container cooling device - Google Patents

Description

r JLTS JTTAK-WA iiT

Dipl. Ing. B. HOIiZEB

«» AÜG8BÜBG num. «1 * 7«

K. 375

Augsburg, June 22, 1971

The British Oxygen Company Limited, Hammersmith House, London W.6 9DX, England

Transport container cooler

The invention relates to a transport container cooling device.

In particular, the invention includes the use of such a cooling device in containers for perishable

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Goods, for example to keep the goods in question at a temperature below the ambient temperature The cooling device according to the invention can be used in connection with railroad cars, road vehicles, transportable and portable Containers use.

According to known proposals for cooling insulated food containers, liquid gas sources are used, which are each connected to a thermostatically valve-controlled spray system and thereby to the relevant container Release nitrogen, through which the temperature is kept at a value at which the decay or spoilage of the Food is delayed. Such known systems are relatively complicated and the low temperatures, with which they must necessarily work, led to difficulties in the puncture ability of the thermostat and the Valves.

The invention aims to achieve the object of simplifying the known transport container cooling device and train it so that it has no moving parts.

This object is achieved according to the invention by a vaporized gas in the interior of the relevant transport

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container feeding liquid gas evaporator, which has a housing with a jacket made of gas-impermeable material, further an insulation layer, further an inlet for liquid gas and finally a steam outlet leading directly to the transport container interior _t whereby the position and the dimensions of the steam outlet a leakage of tight, not Allow turbulent, vaporized gas.

According to the invention, the mean conductivity of the vaporizer is preferably in the range between 0.02 and O, Oil kcal / 930 cm ² / 2.54 cm / | ° C / h (equal to 0.08 to 0.155 BTU / sq ft / inch / ° F / h).

The invention also relates to transport containers which are provided with a cooling device according to the invention.

According to the invention, the evaporator forms a cooling gas source in a self-contained transport container, which cools the transport container and, according to the invention, envelops the goods in the transport container in a layer of dense, evaporated gas. This layer is extremely effective in maintaining refrigerated packages, such as cartons of frozen food, at a low temperature. It comes about because the evaporation of the liquefied gas according to the invention takes place in a region of low turbulence. It is

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It is therefore important that conditions of turbulence are avoided, such as those caused by intermittent spraying Liquid gas or the use of massive carbon dioxide as a coolant in the container. The formation of dense cooling gas layers can be supported by the fact that the vapor outlet of the evaporator within the relevant Container is arranged relatively high. If the evaporator itself is located in a low place, so will expediently a chimney is provided, within which the tight gas to a higher point in the transport container can be directed.

In the context of the invention it has been shown that the "packaging effect" of the dense steam has the effect that the temperature of the packages in question in the container is kept essentially at a constant temperature value. Surprisingly, this effect is both frozen food (for example at about -18 ⁰ C) as well as in refrigerated foods fc available (for example at about +4 ⁰ C). In fact, the experiments showed that the effect of the dense vapor layer in keeping the packages it encompasses at a reduced temperature is much greater than the heat sensing capacity of the liquefied gas. The most important requirement of the container in question is that it should support the non-turbulence. In contrast, the

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Isolation of the container in question surprisingly be very weak, which makes it possible according to the invention to Transport of heat-sensitive goods also to use common transport containers, which do not have any special insulation exhibit.

Of course, the evaporator must be of such a size that it has the required length for a certain period of time Amount of dense gas can generate. In the case of road transport vehicles, the required period of time is during which Gas must be generated, typically about 8 to 12 hours. Preferably, for every cubic meter of container interior space, approximately 0.5 kg / h to 2.0 kg / h liquid gas evaporates.

Liquid nitrogen or liquid argon is preferably used as the liquid gas.

The evaporator housing can be made of metal and / or plastic exist. Suitable materials for the evaporator housing are, for example, aluminum, rust-free iron and polytetrafluoroethylene. If desired, the housing can also be a composite construction of alternately successive Have layers of metal and plastic.

The insulation layer is preferably made of a solid one

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Insulation means formed, for example from foamed Plastic, e.g. expanded polystyrene, and can be in the form of powder material or granular material or uninterrupted Have layers or plates. The insulation layer is expediently housed in an outer jacket which, similar to an inner jacket of the housing, made of metal and / or plastic. A particularly suitable, massive one Isolation means is a strip of foamed polystyrene wrapped around an inner jacket. This enables a simple manufacture of the evaporator.

If there is no or only partially an outer jacket, the insulation is expediently around one Inner jacket arranged around that no part of the inner jacket is exposed, which has such a low temperature that its Touch becomes dangerous.

Notwithstanding this, the insulation layer can also have the shape of a gas jacket, for example an air jacket or nitrogen jacket, in which case a gas-tight outer jacket is required.

A drip tray is expediently located at the foot of the evaporator arranged from which a drain line from the relevant Container leads out.

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The interior of the evaporator can be provided with support or stiffening elements. These stiffen the evaporator, so that it withstands the stresses better that occur during the filling of the evaporator, when this case has a temperature above OC temperature, while the material introduced into it liquefied gas has a temperature of for example -200 ⁰ C. In addition, the support elements dampen the movement of the liquid within the evaporator while it is in motion. The support elements are expediently in the form of perforated plates which are arranged transversely within the evaporator. Usually two such support elements are sufficient.

It has been shown that the evaporator expediently has an elongated shape and the evaporator with its longest Dimension is arranged vertically. In such a vaporizer, the dense, vaporized gas, which via the Outer walls flowing down an insulating jacket for the evaporator, which further isolates the evaporator only needs to have a relatively small strength. Such an evaporator preferably has in horizontal section an oval cross-sectional shape. This causes the evaporator to protrude less far into the hold of the container in question than when it has a circular cross-section would have, with the oval construction being stronger than square or rectangular cross-sectional shapes.

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The steam outlet is preferably arranged centrally in the top wall of the evaporator. The steam outlet is expedient not too small, so that it is not easily clogged by ice formation, but also not a turbulence of the outflowing Gas. A circular steam outlet cross-section is then useful if the diameter of the steam outlet is smaller than 25 mm. The passage cross-section of the steam outlet but should also not be so large that a large amount of warm gas can enter and come into contact with the liquid gas can come. Therefore the ratio of the passage cross-section of the steam outlet to the surface area in the evaporator should be existing liquid according to the invention in the range between 1: 8 and 1:80.

Although several steam outlets are provided for the vaporized gas can be, only a single steam outlet is expediently used, since then in the one from the evaporator emerging vaporized gas least turbulence can occur.

Of course, the steam outlet can also be used as a liquid gas inlet may be used, but a liquid gas inlet separate from the steam outlet is expediently provided. Of the Vaporizer can either be in place in the container in question or, if it is portable, outside the container

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filled and then brought into the required position in this. According to an expedient embodiment of a container According to the invention, a liquid gas supply line is provided, which from the evaporator housed in the container to a Leads provided on the outside of the container inlet opening, so that the evaporator from outside the container can be filled forth.

Any lines leading to the evaporator should be covered with a protective layer. This will reduce cold losses reduced by the vaporizer and there is also a "cold burn" protection for people who enter or reach into the container in question.

If the container has an inner jacket and an outer jacket, the top wall of the inner jacket is expedient provided with passage openings. This ensures that vaporized gas is in the between the two jackets Space can enter, and it reduces the possibility that air will condense in that space and become oxygenated enriched liquid air results. Such enriched air can prove dangerous if it is in between the space between the two coats comes into contact with flammable material.

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The container in which the vaporizer is housed is expediently provided with a written warning, that gases such as nitrogen and argon are not toxic, but can cause asphyxiation, with in addition, a written warning is attached to indicate that it should be taken into account when filling the vaporizer care must be taken that no impermissible pressure builds up in the container concerned.

Two embodiments of the invention are shown in the drawings and are described in more detail below, Show it:

Fig. 1 is a schematic vertical section

an insulated container with an evaporator housed therein according to the invention,

Fig. 2 is a schematic section longitudinally

the plane A-A in Fig. 1, and

3 shows a schematic vertical section

another embodiment of an insulated container with an evaporator housed therein according to the invention.

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ORIGINAL INSPECTED

The evaporator shown in Figs. 1 and 2 after Invention has an inner jacket 2 made of stainless steel, which is surrounded by an insulation layer 4, which consists of several Layers made of foamed polystyrene. The insulation layer is covered with an outer jacket 6 made of polystyrene.

A supply line 8, 10 opening into the interior of the inner jacket 2 has a lead to the outside of an insulated container 12 leading line section 10 on. The line section 10 has a valve-controlled inlet opening outside the container 12 14. An overflow line 16 leads from the upper part in the interior of the inner jacket 2 via a line 18 to the outside of the container 12.

Through the top wall of the inner jacket 2, the insulation layer 4 and the outer jacket 6, a cylindrical Steam outlet 20 therethrough.

The thermal conductivity of the evaporator in this example of the invention is 0.0277 kcal / 930 cm ² / 2.54 cm / | ° C / h.

The evaporator according to the invention is 1.6 m wide, 0.4 m high and 0.3 m deep. The supply line 8, 10 is

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ORJQfNAL INSPECTED

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a tube with 25 now diameter and the steam outlet 20 is a Cylinder with a diameter of 35 mm.

Liquid gas is so long in the inner jacket for operation 3 introduced until the liquid level has reached the inlet of the overflow line 16. Dense steam escapes then through steam outlet 20 into container 12.

The one in fig. 3 as a further example shown evaporator according to the invention has an inner jacket 3 made of aluminum, which has an oval cross-sectional shape and is surrounded by an insulating layer 5, this insulating layer is formed by first fabric and then polystyrene strips are wound onto the inner jacket 3 * The insulation layer 5 is enclosed by an outer jacket 7 made of aluminum * The outer jacket 7 stands in a drip tray 22, which is located on the bottom 2k of the container 13 near a side wall of the same. In the middle of the top wall of the inner jacket 3j of the insulation layer 5 and the outer jacket 7 is a steam outlet 26 which is circular in cross section. The top wall of the inner jacket 3 is provided with a large number of openings 28. Perforated support or stiffening plates 30 are arranged in the interior of the inner jacket 3. A feed line 32 used for filling and an overflow line 3 ** lead from a hollow hub-like part 36 from the side wall outside of the

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Container 13 in the upper part of the inner jacket 3. The supply line 32 runs in a straight line through the hollow hub-like part through and is by means of a sealing washer 40 having Cap 38 closed, which is removed during the loading process. The overflow line leads into the interior of the hollow hub-like part 36 and has with an outlet port 42 connection.

The exposed parts of the supply line 32 and the overflow line 34 are in the Pig. 3 can be seen Surrounded by an insulation 44. From the bottom of the drip tray 22, a drain line 46 leads through the wall of the Container 13 through to the outside thereof.

To fill the vaporizer, the cap 38 is removed and liquid gas from a memory into the vaporizer initiated. When the evaporator is initially at ambient temperature, what was initially introduced evaporates Liquid gas relatively quickly, which means that it produces cold vapor Gas for cooling the evaporator and the interior of the container 13 is generated. When the surface level of the Liquefied gas has reached the upper end of the overflow line 34, liquid gas flows through this overflow line 34 and the hollow hub-like portion 36 to outlet opening 42, which indicates that the evaporator is full.

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The evaporator described with reference to FIG. 3 according to the invention is, for example, 1.8 m high and it has a largest diameter of 0.3 m and the steam outlet 26 has a clear diameter of 75 mm. You mean heat

2 conductivity of this vaporizer is 0.0277 kcal / 930 cm /

5 ο
2.54 cm / -jr C / h at the evaporation temperature of liquid nitrogen, i.e. at -196 ⁰ C.

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Claims (31)

AS Claims; / 1.! Transport container cooling device, characterized by a liquid gas evaporator which feeds vaporized gas into the interior of the relevant transport container (12 or 13) and has a housing (2, 4, 6 or 3, 5, 7) with a jacket (2 or 3) made of gas-impermeable material, further an insulation layer (4, 6 or 5 * 7) » further an inlet (8, 10, 14 or 32, J6) for liquid gas and finally a steam outlet leading directly to the interior of the transport container (20 and 26, respectively), the position and dimensions of the steam outlet allowing dense, non-turbulent, vaporized gas to escape. 2. Cooling device according to claim 1, characterized in that the evaporator has an average conductivity in the range between 0.02 and 0.04 kcal / 930 cm ² / 2.54 cm / § · ° C / h. 3. Cooling device according to claim 1 or 2, characterized characterized in that the outlet (20 or 26) of the evaporator is arranged relatively high, for example in the top eighth of the interior of the transport container. - 15 - TO9853 / 13U 4. Cooling device according to claim 1 or 2, characterized in that the steam outlet (20 or 26) of the The evaporator is arranged relatively low and the evaporator is provided with a chimney through which the dense gas is brought to a higher position. 5. Cooling device according to one of claims 1 to 4, characterized in that the housing jacket (2 or 3) of the evaporator is made of metal. 6. Cooling device according to one of claims 1 to 4, characterized in that the housing jacket (2 or J5) of the evaporator is made of plastic. 7. Cooling device according to one of claims 1 to 4, characterized in that the housing of the evaporator is a composite construction of alternating layers of metal and plastic 8. Cooling device according to one of claims 1 to J, characterized in that said insulation layer (4 or 5) of the evaporator is enclosed by an outer jacket (6 or 7). 9. Cooling device according to one of claims 1 to 8, - 16 1 09853/13 tA characterized in that the insulation layer (4, 6 or 5 * 7) of the evaporator is formed from a solid insulation medium. 10 * cooling device according to claim 9 * characterized in that that the massive insulation is foamed plastic. 11. Cooling device according to claim 8, characterized in that said insulation layer of the evaporator is formed by a gas jacket. 12. Cooling device according to one "of claims 1 to 11, characterized in that the evaporator is provided with a drip tray (e.g. 22). 13 · Cooling device according to claim 12, characterized in that that the drip tray (e.g. 22) is connected to the exterior of the transport container (e.g. 13) has an upright drainage line (e.g. 46). 14. Cooling device according to one of claims 1 to I3, characterized in that the inside of the evaporator is provided with support or stiffening elements (30) is provided. - 17 109853 / 13U Af 15 cooling device according to claim 3.4, characterized in that that the support or stiffening elements are transversely arranged in the evaporator, perforated plates (JO). 16. Cooling device according to one of claims 1 to 15 » characterized in that the evaporator has an elongated shape and is arranged with its longest dimension vertically, ie on edge. 17. Cooling device according to one of claims 1 to 16, characterized in that the evaporator in horizontal section has an oval cross-sectional shape. 18. Cooling device according to one of claims 1 to IJ, characterized in that the steam outlet (20 or 26) is arranged centrally in the upper wall of the evaporator. 19. Cooling device according to one of claims 1 to 18, ) characterized in that the ratio of the passage area the vapor outlet (20 or 26) to the surface of the liquid present in the evaporator in the area is between 1: 8 and 1: 8o. 20. Cooling device according to one of claims 1 to I9, characterized in that the evaporator has only one - 18 - 9853/1314 A9 single steam outlet {dO dzw. 2t>). 21. Cooling device according to one of claims 1 to 20, characterized in that the liquid gas inlet (8, 10, 14 or 52, 36) of the evaporator from the steam outlet (20 or 26) is separated. 22. Cooling device according to one of claims 1 to 21, characterized by a liquid gas supply line (14, 10 or 36), which from the evaporator to an outside of the Transport container (12 or I3) located inlet opening (at 14 or at 36) leads. 23 · Cooling device according to one of Claims 1 to 22, characterized in that all of them are connected to the evaporator Lines (e.g. 8, 10, 14 or 32, 36) respectively are surrounded with a protective layer. 24. Cooling device according to one of claims 1 to 23, characterized in that the housing of the evaporator has an inner jacket (2 or 3) and an outer jacket (6 or 7) and the upper part or cover part of the inner jacket is provided with passage openings (28). 25. Cooling device according to one of claims 1 to 2λ, - 19 - 109853 / 13U ORIQlNAL tNSPECTED U) characterized in that the evaporator is designed in such a way is that it evaporates 0.5 kg / h to 2.0 kg / h liquid gas per cubic meter of interior space of the transport container (12 or 13). 26. Cooling device according to one of claims 1 to 25, characterized in that the liquid gas of the evaporator is liquid nitrogen. 27 »Cooling device according to one of claims 1 to 26, characterized in that the liquefied gas of the evaporator is liquid argon. 28. A cooling device according any one of claims 1 to 27, characterized ^by: an out of the evaporator herausj führenden.Überlauf (16, 18 or 34). j 29. Cooling device according to one of claims 1 to 28, j characterized in that the liquid gas inlet line ί (e.g. 32, 36) and any overflow \ line of the evaporator inside the evaporator in horizontal * Direction are supported. 30, cooling device according to claim 29, characterized in that for horizontal support of said - 20 - 109853/1314 originally inspected I t Lines arranged horizontally, perforated plates (e.g. 30) serve. 31. Application of a cooling device according to one of the Claims 1 to 30 to containers for perishable goods. - 21 - ORIGINAL INSPECTED 109853/1314 Blank first