GB2333828A

GB2333828A - Temperature control of container borne cargo in a ship's hold

Info

Publication number: GB2333828A
Application number: GB9826709A
Authority: GB
Inventors: William Herbert Falconer; John Thompson Newton
Original assignee: BLUE FUNNEL LINE Ltd
Current assignee: BLUE FUNNEL LINE Ltd
Priority date: 1998-01-30
Filing date: 1998-12-07
Publication date: 1999-08-04
Anticipated expiration: 2018-12-07
Also published as: GB9826709D0; DE19882297T1; WO1999038768A1; PL335943A1; GB9801932D0; GB2333828B; AU9638798A; JP2000515832A

Abstract

The temperature of container borne cargo in a ship's hold is controlled by using a gas distribution chamber (8) having a number of outlets (22) for passing gas into respective containers (2) in the hold. A fan or other means is provided to propel gas from the hold to the gas distribution chamber, and means eg a refrigeration unit are provided for controlling the temperature of gas entering the containers. In operation, gas from the distribution chamber passes into and through the containers, thereby controlling the cargo temperature, and then escapes from the containers via outlets (26) into the hold to be re-circulated by the fan. Preferably, the outlets (22) and the corresponding container inlets (24) lack any means for forming a sealed connection; gas being blown from one through the other in use. The inlets (24) may be shaped venturi fashion to promote air flow.

Description

DESCRIPTION APPARATUS FOR TEMPERATURE CONTROL OF CONTAINER BORNE CARGO IN A SHIP'S HOLD. AND CONTAINER FOR USE THEREWITH.

The present invention is concerned with temperature control of container borne cargo in a ship's hold.

There are several existing systems which enable ships to transport container borne cargo at controlled temperatures.

Conventional reefer ships have cargo holds which are thermally insulated and provided with refrigeration means for circulating cooled air through the hold, the entirety of which is thereby maintained at a reduced temperature. Each hold is relatively small, and typically roughly 2.2 metres in height. Cargo transported by such ships is borne on pallets, whose structure provides spaces for circulation of the cooled air through the hold.

Unfortunately, such ships are expensive to construct and have high operating costs. A particular problem is that loading of the pallet borne cargo is a slow process - it can take three days in a port to load a ship. Aside from the costs of labour and of keeping the ship in port, this delay also reduces the shelf life of goods reaching the customer, and so reduces their value.

One alternative, which has the advantage of allowing transport of goods in containers, involves provision of each container with its own refrigeration unit for circulating cooled air through the container interior, and with its own thermal insulation to minimise heat transfer from the container's surroundings. When installed in a ship, each such container is connected to a ship borne electrical supply and, when containers are stowed below deck, to a source of cooling water.

Disadvantages of this system include high cost of manufacture and maintenance of the containers themselves and reduced storage capacity, due to the volume taken up by the container's thermal insulation. It is also disadvantageous that when loading the ship each container must be connected to the electrical supply (and where applicable to the source of cooling water), which is a time consuming process. Further, a ship's cargo typically comprises a large number of containers which increases the risk of failure of one or more container refrigeration units in the course of a voyage. Such failures, involving wastage of the contents of an entire container, can be highly expensive.

Still another known system utilises containers (known as "blown air boxes") which are each provided with a respective inlet and outlet for releasable connection to a ship borne source of cooled air. In one such system, which has proved commercially successful, the ship is provided with a central refrigeration plant which outputs liquid coolant at low temperatures.

This coolant is brine - a calcium chloride solution having a freezing point well below -30 C. The coolant is circulated through ship borne conduits to a number of heat exchangers, each heat exchanger being allocated to a respective bank of containers. The heat exchangers are used to cool air, which is then supplied through a ship borne system of ducting and connectors to the inlets of the containers themselves.

As an alternative, the heat exchangers may be cooled by a directly expanded refrigerant, typically Freon, which is delivered to the heat exchangers under pressure from a central source. Gas leakage can be problematic.

Connections between the ship borne (cooled air carrying) ducting and the inlets and outlets of the containers are airtight, being formed through releasable, pneumatically operated connectors. Each such connection is monitored using an electrical detector to ensure that the connections are correctly made, and remain so during a voyage. In such a system, the containers are each closed but for their inlet and outlet, and air circulates between the heat exchanger and the containers in a closed loop. The containers are each provided with thermostatic temperature control, allowing internal container temperatures to be very closely regulated.

Despite its commercial success, this system too suffers from drawbacks. The ship borne system for distributing the cooled air, having an inlet, an outlet and corresponding ducts for each cooled container, is highly complex and adds significantly to the cost of construction of the ship.

Typically, the cooling apparatus accounts for roughly 25% of the cost of the ship. A large number of the pneumatically operated connectors is required, and these too prove costly to manufacture, install and maintain. As with the above described containers provided with their own refrigeration units, the blown air boxes must incorporate insulation, reducing their cargo carrying capacity.

The present invention is intended to overcome or alleviate at least some of the shortcomings of the above described systems.

In accordance with a first aspect of the present invention, there is provided apparatus for temperature control of container borne cargo in a ship's hold, the apparatus comprising a gas distribution chamber having a plurality of outlets for passing gas into respective containers in the hold, fan means which propel gas from the hold to the distribution chamber, and temperature control means for controlling the temperature of the gas before it enters the containers, so that in use gas from the distribution chamber passes into and through the containers to control the cargo temperature and escapes from the containers into the hold, out of which the gas is propelled by the fan means and thereby re-circulated to the gas distribution chamber.

Thus, in the system according to the present invention, gas is circulated through the containers and via the hold itself. In comparison with the conventional blown air box system described above, this aspect in itself considerably simplifies construction of both the ship-borne gas circulation system and the containers, since the gas output from the containers can simply be via openings in the container through which gas passes into the hold, rather than via an outlet hydraulically coupled to ship-borne ducting.

Since the cooled gas is partly or wholly re-circulated, albeit via the ship's hold, the thermal efficiency of the apparatus according to the present invention is acceptable. It is particularly preferred that the hold is thermally insulated. In this way, warming of the gas during its passage through the hold (a source of inefficiency) is reduced. It is also preferred that the hold is at least substantially closed to the exterior. Hatches and other apertures communicating with the hold are preferably sealable. In this way, exchange of gas with the exterior (another source of thermal inefficiency, since relatively warm air can thereby be admitted) can be controlled. In this case, the gas is preferably circulated in an at least substantially closed loop.

Nevertheless, an air freshening system may be provided. Such systems are used for controlling the level of pollutant gases - CO2 and ethylene in particular - in the hold. These gases are emitted, for example, by ripening fruit, and undesirably accelerate ripening. Known air freshening systems admit exterior air to the hold in dependence on the level of pollutant gases in the hold. Typically, servo motors are used to open/close vents to the exterior of the hold. The valves are controlled through sensors monitoring the hold atmosphere.

The system may additionally comprise a plant to generate air having the required oxygen and nitrogen levels. Preferably, the air generated has 97 % nitrogen.

It is particularly preferred that the gas distribution chamber is formed as a plenum chamber, its outlets comprising apertures in the chamber wall. In this way, the complex system of ducting by which individual containers are, in the known blown air box system, connected to the source of cooled gas can be largely dispensed with.

According to yet a further preferred aspect of the present invention, at least one of the outlets from the distribution chamber comprises a nozzle opening which is not provided with means for forming a sealed connection to the container but which is positioned to blow the cooled gas into the container through a corresponding container inlet opening. Where the distribution chamber is formed as a plenum chamber, the nozzle openings are preferably formed as apertures in the plenum chamber wall. The chamber wall in question is most preferably planar, and may be formed by a bulkhead or false bulkhead of the ship.

It has been found that gas can be blown from the nozzle openings into the containers across a gap between the two, without a noticeable loss of gas into the hold. Again, this feature simplifies construction, both of the shipborne gas circulation system, which does not require hydraulic connectors as used in the prior art blown air box system, and of the container, which need not have means for accepting the connection. It also greatly reduces the time and effort involved during loading of cargo, since having simply been placed in the appropriate position in the hold, the containers used with the apparatus according to the present invention are ready for cooling operation - no connection need be made or checked.

The cooling means used in the apparatus according to the present invention preferably comprise a central source of cooling medium connected to a plurality of cooling units.

In accordance with a second aspect of the present invention, there is a ship provided with apparatus according to the first aspect of the invention.

In accordance with a third aspect of the present invention, there is a container for use with apparatus according to the first aspect of the invention, the container comprising an inlet aperture formed through an exterior wall of the container and communicating with the container's interior, the inlet opening being disposed to substantially align with a corresponding outlet nozzle opening of the apparatus so that gas may be blown into the container, and the container further comprising at least one outlet through which gas may escape from the container.

The container may be provided with thermal insulation to reduce heat exchange with the exterior.

Preferably, a duct is defined immediately downstream of the inlet opening, the duct being shaped to promote flow of gas into the container. To this end, the cross section of the duct may include an intermediate restricted region. In this way, by virtue of the venturi effect, air flow into the duct may be promoted.

The duct may be circular, such that airflow within it is substantially radial.

It is preferred that the container further comprises means defining a plenum chamber, such that the inlet aperture communicates with the interior of the container via the plenum chamber and via a supply opening between the plenum chamber and the interior.

The duct is preferably formed by an opposed pair of partitions within the plenum chamber.

Provision of such a plenum chamber, at a point in the airflow between the inlet opening and the interior of the container, allows the pattern of flow in this region to be controlled, without being disturbed, (eg by the container's contents) in a manner which promotes the flow of air into the container.

Guide vanes may be provided in the plenum chamber to guide gas toward the supply opening.

The supply opening is preferably remote from the outlet opening of the container, so that gas must traverse a large part of the container before escaping. Gas is preferably circulated throughout the full length of the box.

Preferably the supply opening is on a lower part of the container and the outlet opening in an upper part.

The plenum chamber may be formed by a partition of the container. This partition may be secured to corner posts of the container.

It is especially preferred that at least one baffle is provided in the container to close or constrict a selected route for passage of gas through the container and thereby promote flow of air through cargo packed within the container. This is particularly useful with a cargo such as bananas, which degrade quickly if air is not circulated around them. The baffle may take the form of a hinged plate positioned to rest on an upper region of a stack of cargo in the container and thereby to prevent passage of air through the space between the top of the stack and the container roof.

In accordance with a fourth aspect of the present invention, there is a container for use in transport of cargo at reduced temperature, comprising a plenum chamber which communicates with the exterior via an inlet opening and with the interior of the container via a supply opening, the container further comprising at least one outlet opening, at a position remote from the inlet openings, through which the interior of the container communicates with the exterior, such that gas may be blown into the plenum chamber through the inlet opening and thereby passed through the supply opening and through the interior of the container to cool its contents, exiting the container through the outlet opening.

A system embodying the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Fig. 1 is a longitudinal section through a part of a ship's hold, showing a stack of containers carried by the ship; Fig. 2 is a longitudinal section through one such container and through a neighbouring distribution chamber of the ship; Fig. 3 is a perspective, partly cut-away view of one of the containers; Fig. 4 is a perspective view of part of a beam used in the construction of the container, having openings for outlet of air from the container; Fig. 5 is a cross sectional view of a pair of fairings forming an inlet duct of the container; Fig. 6 is a front view of one of these fairings, an inlet opening and a cover being shown in dotted lines; Fig. 7 is a cross section through a simplified nozzle construction for the container; and Fig. 8 is a cross section through a further container embodying the present invention.

Fig. 1 illustrates a stack of containers 2 carried in the hold of a ship, and forming part of a larger bank of containers consisting of several such stacks disposed side by side across the ship. The containers are of the general type which is very widely known and used in shipping and other transport, consisting principally of a metal box of standardised external dimensions.

Positive location of the containers in the hold is provided by a conventional system of guides, of a type well known to those skilled in the art and not described further herein. A maximum tolerance of the order of 2.5cm in the longitudinal positioning of the containers is typically achieved using such guides.

In Figs. 1 and 2, the tank top (the horizontal surface forming the bottom of the hold) is labelled 4, while the vertical planar member 6 is a bulkhead of the ship.

The apparatus for circulating cooled air through the containers includes a distribution chamber 8, formed between the bulkhead 6 and a false bulkhead 10. In the present embodiment the false bulkhead is a panel of marine grade plywood or galvanized sheet steel positioned parallel to the bulkhead 6 but separated therefrom in the ship's longitudinal direction. It should be noted that a further false bulkhead 12 is provided, being separated from the first by the bulkhead 6 itself and forming a further distribution chamber associated with a further bank of containers (not illustrated).

At its upper end, the distribution chamber 8 is enclosed by a horizontal partition 14, above which the space between the bulkhead 6 and the false bulkhead 10 forms a circulation chamber 16. An opening along the upper part of the false bulkhead 10 forms an air circulation inlet 18 by which the circulation chamber communicates with the hold itself.

To produce the necessary cooling, a refrigeration/fan unit 19 is provided. The refrigeration/fan unit acts as a heat exchanger. It receives coolant such as brine or freon from a collective cooling plant via ship borne ducts, and uses this to cool the air being circulated. Typically, a ship has a number of collective cooling plants.

In operation of the system, air circulates as indicated by arrows in Figs. 1 and 2, as follows.

The refrigeration/fan units 19 draw cooled air from the circulation chamber 16 to the distribution chamber 8, raising the pressure of the latter above ambient. The distribution chamber acts as a plenum chamber: air is expelled from the distribution chamber via nozzle openings 22 formed as holes in the false bulkhead 10. This air is then blown into the containers through corresponding inlet openings 24 formed in the container walls. The detail of these openings, and the path taken by the air passing through a container, will be explained in more detail below. For the time being, it suffices to state that air eventually leaves each container through outlet baffles 26 and thereby passes into the free volume within the hold, whence it eventually returns through the air circulation inlet 18 to the air circulation chamber.

To minimise leakage of heat, causing undesirable warming, the ship's hold itself is thermally insulated, and the loop through which air circulates is substantially closed - ie. the hold is at least substantially sealed but for the inlets/outlets forming part of the loop, largely constraining the air to take the path described above and at least substantially preventing entry of warmer air from the exterior.

However, provision is made for air to be exchanged with the exterior in order to freshen the air in the hold. To this end, an air freshening system (not illustrated) is provided which utilises valves which can be opened to admit air from the exterior to the hold. The hold atmosphere is automatically sampled, and the valves are opened when necessary to reduce levels of undesirable gas, such as CO2 and ethylene.

The construction of the containers, and the passage of air into and through them, will now be described.

Fig. 3 illustrates the exterior of a container for use in the system being described. The container is of largely conventional construction, being formed as a cuboidal metal box the interior of which is typically accessible through a pair of hinged doors (which form an end face of the box which faces away from the observer in Fig. 3 and hence is not seen). The box has metal girders 29 which form its vertices and its robust framework. The walls of the container may comprise thermal insulation, to minimise heat exchange with the exterior.

One feature which distinguishes the illustrated container from a conventional unit is that the hollow beams 30 extending horizontally along upper parts of the two longer vertical walls of the container, are provided with outlet baffles 26 through which air escapes from the container in use. The relevant construction is most clearly illustrated in Fig. 4, in which it will be seen that the vertical inner and outer faces of the beam are penetrated in selected areas by holes 32. These are of small diameter, thereby making it impossible to insert contraband into the beam, and avoiding the suspicion of customs authorities. A filter mesh 34 lies adjacent the holes 32 in the outer beam-face, covering the holes in that face to prevent ingress of foreign objects.

Finally an upright planar plate 36 is provided within the beam, helping to prevent ingress of liquid, particularly rainwater, into the container.

The container is also adapted for use in the present system in that it comprises a plenum chamber through which cooling air passes. As shown in Fig. 2 the end face of the container is formed by an upright, planar outer panel 38, and the plenum chamber 40 is formed between this and an upright, planar inner panel 42. For the sake of constructional convenience, these two, parallel, panels are separated by a distance corresponding to the depth of a corner post 44 of the container framework.

The inlet opening 24 to the plenum chamber 40 is formed as a circular hole in the outer panel 38 which communicates directly with the plenum chamber.

When the container is carried aboard ship, as illustrated in Figs. 1 and 2, its inlet opening is approximately vertically and horizontally aligned with one of the nozzle openings 22 formed in the ship's false bulkhead 10. To accommodate slight misalignment, the inlet opening 24 is larger in diameter than the corresponding nozzle opening 22 - see Fig. 2. During operation of the cooling system, air is blown from the nozzle opening 22, through the inlet opening 24 and into the container's plenum chamber 40. It should be noted that whereas in the prior art air blown box system a sealed connector was provided to conduct the cooled air into the box, no such connector is provided in the present system. Indeed, the outer panel 38 in which the inlet opening is formed is typically separated by a short space 46, of the order of 10cm, from the false bulkhead 10 having the nozzle opening 22. Thus, the cooling air must traverse a short open space to enter the container. Nonetheless, it has been found experimentally that in the illustrated system the great majority of air emitted from the nozzle opening enters the container, rather than escaping through the gap 46 between the container and the false bulkhead.

To promote this desirable flow of air into the container, fairings 48, 50 are provided within the plenum chamber 40 to form a shaped duct 52 (most clearly seen in Fig. 5) through which air entering the chamber passes.

Both fairings are, according to the present invention, circular and concentric with the inlet opening 24, as will be apparent from a study of Figs. 2 and 3.

The fairing 48 has an approximately conical surface facing the inlet opening 24, tending to deflect air, which enters the plenum chamber along a direction roughly perpendicular to the container face, toward a direction roughly parallel to this face, as the arrows in Fig. 2 indicate. The fairing 48 is not precisely conical in the region of the inlet; rather, its surface is concave in cross section, as Fig. 5 makes clear, which assists in promoting smooth flow of air.

The fairing 50 is formed as a torus which surrounds the inlet opening 24, being mounted within the plenum chamber on a surface of the container's outer panel 38 and having a surface 52 which faces the fairing 48.

It is considered that due to its shape, the circular duct 52 formed by the two fairings acts analogously to a venturi, tending to promote airflow into the plenum chamber. To explain, the illustrated duct is circular, air flow through the duct being along roughly radial directions. Air leaves the duct through the circumferential opening 60, whose total area is approximately equal to the area of the inlet opening 24. In an intermediate region 62, the two fairings converge somewhat, forming a constriction in the duct. In this region air velocity is increased and pressure is reduced, promoting air flow into the duct.

Generally radial vanes 64 connect the two fairings, and by virtue of downwardly curved outer portions 66, tend to deflect the air downwards toward an exit aperture 54.

Typically, air pressure within the ship's distribution chamber 8 is in the region of 300Pascals, while pressure in the container plenum chamber is in the region of l00Pascals.

Having passed through the duct, air moves through the plenum chamber 40 and then into the interior of the container, through the exit aperture 54 formed by a gap between the lower edge of the inner panel 42 and the container floor. The air thus enters the container's interior at the bottom, and the generally upward paths by which it reaches the outlet baffles 26 are indicated by arrows in Fig. 2. Within the container, cargo boxes 56 are supported on pallets 58, whose construction provides open horizontal channels through which the air may pass to permeate the entire container, before passing out of the container to be recirculated, as described above.

When the container is not being cooled, the inlet opening 24 may be closed by a hatch having a tamper evident seal to prevent surreptitious introduction of contraband, illegal substances etc.

The system described can be used for deep refrigeration of cargo at temperatures below -25 C, and also for cooling of cargo such as bananas, deciduous and citrus fruit, whose rate of ripening is temperature dependent, at more moderate temperatures and for the transportation of ammunition, cereals and other commodities which require their temperature to be controlled during the voyage.

Fig. 7 illustrates an alternative construction of the container nozzle, arrived at by development of the previously described nozzle and serving the same function, but considerably simplified in order to reduce manufacturing cost.

In this version of the nozzle, the plenum chamber 100 is again formed between the container's outer wall panel 102 and its corrugated inner wall panel 104.

The nozzle itself is formed between a circular metal fairing 106 within the plenum chamber, having a planar portion 108 and. radially inward thereof, a curved lip 110 formed of spun metal and defining a circular nozzle aperture 112. The lip is welded along its inner edge 114 to the edge of a corresponding aperture in the outer wall panel 102 and along its outer edge 115 to the planar portion 108. The planar portion 108 is maintained in position relative to the outer wall panel 102, spaced therefrom, by spacers 116 secured to both of these parts.

Facing the fairing 106 within the plenum chamber is a planar, circular plate 118, secured to inner wall panel 104 through spacers 120.

In operation it is found that despite the simplified cross section of the nozzle parts, the route for entry of air being defined largely by the planar, parallel fairing portion 108 and plate 118, a venturi effect is created promoting flow of air into the plenum chamber.

It is believed that this venturi effect arises because of radial flow of air in the region 124 between parts 108 and 118. In consequence of this, the effective cross section increases moving in the downstream (radially outward) direction. Hence there is relative constriction of the air flow in the region of the nozzle opening, leading to reduced pressure in that region.

The radial vanes 64 provided in the previously described embodiment to direct flow downward toward an exit from the container's plenum chamber are dispensed with in the Fig. 7 embodiment.

Turning now to Fig. 8 a further container is illustrated which utilises a plenum chamber and nozzle arrangement of the general type already described but which is designed particularly for transport of perishable cargoes over which air must be circulated during transport.

Bananas are one cargo which is particularly troublesome in this respect. These are generally packed for transport in open pallets, and to minimise degradation of the bananas during a voyage it is important that air is circulated through the pallets, removing gases produced by ripening and degradation of the fruit.

In Fig. 8 a conventionally stacked container is illustrated, containing left and right pallet stacks 130, 132 between which is a central, longitudinal passageway 134. The orientation of the pallets is different in the two stacks, so that one stack is wider (in the lateral direction of the container) than the other.

There are two apertures connecting the container interior to the plenum chamber, through which air is input to the container, seen at 136, adjacent the container floor.

Two baffles 138 are provided. Were it not for the baffles, a direct route would be available for passage of air from the plenum chamber aperture 136, via the passageway 134 and space 140 above the pallet stacks to the outlets 142 adjacent the container roof. Air would thus escape from the container without circulating adequately through the stacks.

The baffles take the form of planar panels extending substantially the full length of the container and hinged at respective longitudinal axes 144 to be movable between an inactive position (not illustrated), in which they lie adjacent the container roof and so do not obstruct the container interior, and the active position in which they are seen in the drawing. In the active position, the baffles rest against the upper part of the stack. The lower edge of each baffle may rest on the upper face of the stack, or the baffle may extend slightly below the inner edge of the stack. In either case, pressure exerted on the inner face of the baffle (ie the face lying toward the passageway 136) by incoming air simply urges the baffle against the stack of pallets, the baffle being thereby retained in its active position.

Handles (not illustrated) are provided to move the baffles upward to the inactive position, and a suitable retaining mechanism is used to retain them in this position when not in use.

The baffles serve to close the above described route for passage of air out of the container and so ensure that the air passes instead from the passageway 136 through the pallet stacks and then to the outlets 142. Arrows in Fig. 8 indicate this path. In the way it is ensured that air is passed over the pallet contents.

It is envisaged that ships utilising the system will be well suited to carrying cooled or frozen cargo on one leg of a journey and general cargo, not requiring cooling, on another. Mixed cargoes may also be carried, part being frozen or cooled and part being at ambient temperature.

A further application of ships utilising the system is in transport of armaments such as ammunition and explosives. In this context, an atmosphere very high in Nitrogen and very low in Oxygen is required, and to provide this a membrane filter is provided to filter the circulated atmosphere, reducing its oxygen content.

Once on land, containers may be moved to cold stores equipped with air circulating apparatus akin to that described above for a ship, and hence maintained at appropriately low temperatures.

Claims

1. Apparatus for temperature control of container borne cargo in a ship's hold, the apparatus comprising a gas distribution chamber having a plurality of outlets for passing gas into respective containers in the hold, fan means which propel gas from the hold to the distribution chamber, and temperature control means for controlling the temperature of the gas before it enters the containers, so that in use gas from the distribution chamber passes into and through the containers to control the cargo temperature and escapes from the containers into the hold, out of which the gas is propelled by the fan means and thereby re-circulated to the gas distribution chamber.

2. Apparatus as claimed in claim 1, wherein the temperature control means is such as to cool the gas.

3. Apparatus as claimed in claim 1, further comprising an air freshening system which is such as to selectively admit exterior air in dependence upon the level of pollutant gases in the hold.

4. Apparatus as claimed in claim 3, wherein the air freshening system comprises servo controlled vents in the hold, the vents being controlled through sensors monitoring the hold atmosphere.

5. Apparatus as claimed in claim 1, comprising a plant to generate gas having required oxygen and nitrogen levels.

6. Apparatus as claimed in claim 5, wherein the plant comprises a membrane filter whereby oxygen is removed from the gas.

7. Apparatus as claimed in claim 1 wherein at least one of the outlets from the gas distribution chamber comprises a nozzle opening which is not provided with means for forming a sealed connection to a container but which is positioned and formed to blow gas into the container through a corresponding container inlet opening.

8. Apparatus as claimed in claim 7 wherein the gas distribution chamber is formed as a plenum chamber.

9. Apparatus as claimed in claim 8 wherein the nozzle opening is formed as an opening in the plenum chamber wall.

10. Apparatus as claimed in claim 9 wherein the plenum chamber wall having the opening is a bulkhead or false bulkhead of the ship.

11. A ship provided with apparatus as claimed in any preceding claim.

12. A ship as claimed in claim 11 wherein the hold of the ship is thermally insulated to the exterior.

13. A ship having a plurality of temperature controlled holds respectively provided with apparatus as claimed in any of claims 1 to 10, the ship having at least one main source of cooling medium arranged to supply cooling medium to the respective temperature control means associated with the holds.

14. A container for use with apparatus as claimed in any of claims 1 to 10 or in a ship as claimed in any of claims 11 to 13, the container comprising an inlet aperture formed through an exterior wall of the container and communicating with the container's interior, the inlet opening being disposed to substantially align with a corresponding outlet nozzle of the apparatus so that gas may be blown into the container from the outlet nozzle, and the container comprising at least one outlet communicating with the container interior through which gas may escape from the container.

15. A container as claimed in claim 14, wherein a venturi duct is defined immediately downstream of the inlet opening to promote flow of gas into the container.

16. A container as claimed in claim 15, wherein the duct is annular such that airflow within the duct is substantially radial.

17. A container as claimed in claim 14 further comprising means defining a plenum chamber such that the inlet aperture communicates with the container interior via the plenum chamber and via a supply opening between the plenum chamber and the container interior.

18. A container as claimed in claim 17, wherein the plenum chamber is formed between an exterior wall of the container in which the inlet opening is formed and a partition within the container substantially parallel to the exterior wall, the supply opening being formed in the partition.

19. A container as claimed in claim 17 wherein the supply opening is disposed remote from the outlet opening such that gas must traverse the container before escaping.

20. A container as claimed in claim 17 comprising at least one internal baffle to close or constrict a selected route for passage of gas through the container and thereby promote flow of air through cargo packed within the container.

21. A container as claimed in claim 20 wherein the baffle comprises a hinged plate positioned to rest on an upper region of a cargo stack within the container and thereby to prevent passage of gas through the space between the top of the stack and the container roof.

22. A method of temperature control of container borne cargo in a ship's hold, comprising the steps of providing the container with a container inlet opening and a container outlet opening both communicating with the container interior and providing the hold with a gas outlet opening through which gas can be blown, the method comprising the further steps of disposing the container within the hold such that its inlet opening is aligned with, but not sealingly connected to, the container outlet opening, propelling gas from the hold through the gas outlet opening such that the gas is blown into the container through the container inlet opening and escapes through the container outlet opening back to the hold, and controlling the temperature of the gas propelled through the gas outlet.

23. Apparatus for temperature control of container borne cargo in a ship's hold substantially as herein described with reference to and as illustrated in the accompanying drawings.

24. A ship substantially as herein described with reference to and as illustrated in the accompanying drawings.

25. A container substantially as herein described with reference to and as illustrated in the accompanying drawings.

26. A method of temperature control of container borne cargo in a ship's hold substantially as herein described with reference to and as illustrated in the accompanying drawings.