GB1573994A - Refrigeration apparatus for freight containers - Google Patents

Description

(54) REFRIGERATION APPARATUS FOR FREIGHT CONTAINERS (71) We, AIR PRODUCTS SOCIETY ANONYME, a company organised under the laws of Belgium, of Le Souverain, Boulevard du Souverain 191-197, 1160 Brussels, Belgium and COSEC CONTAINER SERVICE COMPANY N.V., a company organised under the laws of Belgium, of Treurenborg 11, 2032 Antwerp, Belgium do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to refrigeration apparatus for maintaining food in a container in a chilled or frozen state.

The term "container" as used herein refers to large shipping containers which are rectangular and are provided with eight corner pieces (often referred to as "Moscow Boxes") which each have apertures which can receive a peg along one of three mutually perpendicular axis, and an end wall having a pair of portholes which can be connected to supply and return pipes through which cold air can be circulated to maintain food in the container in a chilled or frozen state.

One known mechanical cooling system for containers comprises a housing which can be mounted on the end of a container. The housing covers both the portholes and, in use, a fan in the housing extracts air from one porthole, passes it over a plurality of cooling elements in the housing, and returns the cold air to the interior of the container through the other porthole.

In recent years mechanical cooling systems have been partially superceded by systems which allow liquid nitrogen to be injected directly into the interior of the container. The gaseous nitrogen, which occupies several hundred times the volume of the liquid, displaces air in the container which escapes through one or both the portholes which are left open during nitrogen injection. In practice liquid nitrogen is injected into the container every 24 hours. The temperature of the atmosphere in the container thus varies between for example - 1800C immediately after injection to --100"C immediately prior to the next injection Although once daily liquid nitrogen injection is entirely satisfactory for many purposes it is occasionally desirable to maintain the atmosphere in a container at a substantially constant temperature.

Our first attempts to achieve a substantially constant temperature in a container were made using an apparatus comprising a housing which would cover both portholes on the container, a fan for extracting gas from the container through one of the portholes, passing it through the housing and introducing it back through the other porthole, a nozzle for injecting liquid nitrogen into the circulating gas, and a vent which was adjusted to release excess gas from the container.

The housing was bolted fast to the container by horizontal bolts. Unfortunately however, on wet and/or humid days we found that the vent was liable to freeze with resultant damage to the housing due to excess pressure from the vapourized liquid nitrogen.

In order to help reduce the possibility of such damage we propose to mount refrigeration apparatus on a container in such a manner that if the pressure in the container exceeds a certain amount the refrigeration apparatus will swing away from the container to release the excess pressure and will then swing back to its original position.

According to the present invention there is provided refrigeration apparatus for a container (as herein defined), which apparatus comprises a housing and attachment means provided with a pair of pegs which can be inserted in respective corner pieces on the top of said container and which are so shaped that if, in use, the pressure in said housing exceeds a pre-determined level the housing will swing away from the container to relieve the excess pressure and will then swing back to its initial position.

In order to facilitate moving the housing and mounting it on a container the housing may be provided with wheels and a jack.

The refrigeration apparatus may include a tank for storing liquid nitrogen or may simply be provided with a fitting to which a liquid nitrogen supply pipe can be connected.

The housing itself may be associated with a single porthole, in which event the atmosphere will preferably be blown into the container through a flexible conduit and extracted from the container through the space between the conduit and the porthole. It is however preferred that the atmosphere should be extracted from one porthole and introduced through the other.

The housing of this latter arrangement may, if desired, be provided with one or more liquid nitrogen nozzles adjacent the gas inlet and outlet of the housing respectively. The nozzle(s) adjacent the gas inlet of the housing is used when the container has a delicate cargo, for example chilled fruit, whilst the nozzle(s) adjacent the outlet is used for frozen food. Alternatively both the nozzle(s) adjacent the gas inlet and the nozzle(s) adjacent the gas outlet may be used for frozen food.

For a better understanding of the present invention reference will now be made, by way of example, to the accompanying drawings in which: Figure 1 shows a side elevation of one embodiment of refrigeration apparatus in accordance with the invention mounted on a container, Figure 2 is a view taken along line II-II of Figure 1 but with the front panel of housing 2 removed; and Figure 3 is a cut-away view of the apparatus and container as shown in Figure 1.

Referring to the drawings there is shown refrigeration apparatus which is generally identified by reference numeral 1. The apparatus comprises a housing 2 which contains a fan 3 and two nozzles 4 and 5 which are mounted adjacent housing inlet 6 and outlet 7 respectively.

The housing 2 is mounted on a container 8 by two arms 9 and 10 which are each provided with a peg 11 and 12 which rest in the top aperture of Moscow boxes 13 and 14 on either side of the end wall of the container 8.

To compensate for irregularities in the end wall of the container 8 the inlet 6 and outlet 7 are provided with annular neoprene seals 15 and 16.

An electric heating element 17 is located at the base of housing 2 and can be used for defrosting when necessary.

The housing 2 is provided with wheels 18 and a jack mechanism 19.

Two adjustable vents 20 and 21 are mounted on the housing 2 and are connected to ducts which open immediately upstream of fan 3 and adjacent outlet 7 respectively.

In use, portholes 22 and 23 in container 8 are opened and the apparatus is wheeled into position with the jack mechanism 19 in its raised position.

Pegs 11 and 12 are moved into position above Moscow boxes 13 and 14 and jack mechanism 19 is lowered.

A flexible hose 24, which is connected to an underground nitrogen supply line (not shown) is attached to connector 25.

Liquid nitrogen is then admitted to the housing through valve 26 which is opened and closed in response to a signal from thermocouple 27.

The vapourised nitrogen from nozzles 4 and 5 is circulated through the container by fan 3 in the direction shown by arrow 28. If the cargo in the container 8 is fruit, nitrogen will only be admitted through nozzle 4. If the cargo is frozen, nitrogen will be introduced through both nozzles 4 and 5.

Adjustable vent 20 can be set to intro- duce air into the atmosphere entering the housing 2.

In the normal course of events no excess pressure will develop in the housing 2. However, if adjustable vents 20 and 21 are inadvertently closed or frozen solid, the whole housing 2 can swing pendulously away from container 8 to allow excess gas to escape. The housing 2 will swing back to its initial position on release of the excess pressure.

It should be noted that the pegs 11 and 12 each have an inclined surface 29 and a curved surface 28. The curved surface 28 helps ensure that, in normal operation, the inlet 6 and outlet 7 of the housing 2 remain in close proximity to the portholes 23 and 24 of the container 8.

WHAT WE CLAIM IS: 1. Refrigeration apparatus for a container (as herein defined), which apparatus comprises a housing and attachment means provided with a pair of pegs which can be inserted in respective corner pieces on the top of said container and which are so shaped that if, in use, the pressure

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (4)

**WARNING** start of CLMS field may overlap end of DESC **. apparatus comprises a housing and attachment means provided with a pair of pegs which can be inserted in respective corner pieces on the top of said container and which are so shaped that if, in use, the pressure in said housing exceeds a pre-determined level the housing will swing away from the container to relieve the excess pressure and will then swing back to its initial position. In order to facilitate moving the housing and mounting it on a container the housing may be provided with wheels and a jack. The refrigeration apparatus may include a tank for storing liquid nitrogen or may simply be provided with a fitting to which a liquid nitrogen supply pipe can be connected. The housing itself may be associated with a single porthole, in which event the atmosphere will preferably be blown into the container through a flexible conduit and extracted from the container through the space between the conduit and the porthole. It is however preferred that the atmosphere should be extracted from one porthole and introduced through the other. The housing of this latter arrangement may, if desired, be provided with one or more liquid nitrogen nozzles adjacent the gas inlet and outlet of the housing respectively. The nozzle(s) adjacent the gas inlet of the housing is used when the container has a delicate cargo, for example chilled fruit, whilst the nozzle(s) adjacent the outlet is used for frozen food. Alternatively both the nozzle(s) adjacent the gas inlet and the nozzle(s) adjacent the gas outlet may be used for frozen food. For a better understanding of the present invention reference will now be made, by way of example, to the accompanying drawings in which: Figure 1 shows a side elevation of one embodiment of refrigeration apparatus in accordance with the invention mounted on a container, Figure 2 is a view taken along line II-II of Figure 1 but with the front panel of housing 2 removed; and Figure 3 is a cut-away view of the apparatus and container as shown in Figure 1. Referring to the drawings there is shown refrigeration apparatus which is generally identified by reference numeral 1. The apparatus comprises a housing 2 which contains a fan 3 and two nozzles 4 and 5 which are mounted adjacent housing inlet 6 and outlet 7 respectively. The housing 2 is mounted on a container 8 by two arms 9 and 10 which are each provided with a peg 11 and 12 which rest in the top aperture of Moscow boxes 13 and 14 on either side of the end wall of the container 8. To compensate for irregularities in the end wall of the container 8 the inlet 6 and outlet 7 are provided with annular neoprene seals 15 and 16. An electric heating element 17 is located at the base of housing 2 and can be used for defrosting when necessary. The housing 2 is provided with wheels 18 and a jack mechanism 19. Two adjustable vents 20 and 21 are mounted on the housing 2 and are connected to ducts which open immediately upstream of fan 3 and adjacent outlet 7 respectively. In use, portholes 22 and 23 in container 8 are opened and the apparatus is wheeled into position with the jack mechanism 19 in its raised position. Pegs 11 and 12 are moved into position above Moscow boxes 13 and 14 and jack mechanism 19 is lowered. A flexible hose 24, which is connected to an underground nitrogen supply line (not shown) is attached to connector 25. Liquid nitrogen is then admitted to the housing through valve 26 which is opened and closed in response to a signal from thermocouple 27. The vapourised nitrogen from nozzles 4 and 5 is circulated through the container by fan 3 in the direction shown by arrow 28. If the cargo in the container 8 is fruit, nitrogen will only be admitted through nozzle 4. If the cargo is frozen, nitrogen will be introduced through both nozzles 4 and 5. Adjustable vent 20 can be set to intro- duce air into the atmosphere entering the housing 2. In the normal course of events no excess pressure will develop in the housing 2. However, if adjustable vents 20 and 21 are inadvertently closed or frozen solid, the whole housing 2 can swing pendulously away from container 8 to allow excess gas to escape. The housing 2 will swing back to its initial position on release of the excess pressure. It should be noted that the pegs 11 and 12 each have an inclined surface 29 and a curved surface 28. The curved surface 28 helps ensure that, in normal operation, the inlet 6 and outlet 7 of the housing 2 remain in close proximity to the portholes 23 and 24 of the container 8. WHAT WE CLAIM IS:

1. Refrigeration apparatus for a container (as herein defined), which apparatus comprises a housing and attachment means provided with a pair of pegs which can be inserted in respective corner pieces on the top of said container and which are so shaped that if, in use, the pressure

in said housing exceeds a pre-determined level the housing will swing away from the container to relieve the excess pressure and will then swing back to its initial position.

2. Refrigeration apparatus as claimed in Claim 1, wherein said housing is provided with wheels and a jack.

3. Refrigeration apparatus as claimed in Claim 1 or 2, wherein said housing is provided with an inlet porthole and an outlet porthole remote from said inlet porthole and one or more nozzles for dispensing a cryogenic liquid are provided adjacent the inlet of the housing and one or more nozzles for dispensing cryogenic liquid are provided adjacent the outlet of the housing.

4. Refrigeration apparatus substantially as hereinbefore described with reference to and as shown in the accompanying drawings.