Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
  • B63J—AUXILIARIES ON VESSELS
  • B63J2/00—Arrangements of ventilation, heating, cooling, or air-conditioning
  • B63J2/02—Ventilation; Air-conditioning
  • B63J2/08—Ventilation; Air-conditioning of holds
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
  • B63B—SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING 
  • B63B25/00—Load-accommodating arrangements, e.g. stowing, trimming; Vessels characterised thereby
  • B63B25/002—Load-accommodating arrangements, e.g. stowing, trimming; Vessels characterised thereby for goods other than bulk goods
  • B63B25/004—Load-accommodating arrangements, e.g. stowing, trimming; Vessels characterised thereby for goods other than bulk goods for containers
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25D—REFRIGERATORS; COLD ROOMS; ICE-BOXES; COOLING OR FREEZING APPARATUS NOT OTHERWISE PROVIDED FOR
  • F25D15/00—Devices not covered by group F25D11/00 or F25D13/00, e.g. non-self-contained movable devices
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25D—REFRIGERATORS; COLD ROOMS; ICE-BOXES; COOLING OR FREEZING APPARATUS NOT OTHERWISE PROVIDED FOR
  • F25D17/00—Arrangements for circulating cooling fluids; Arrangements for circulating gas, e.g. air, within refrigerated spaces
  • F25D17/04—Arrangements for circulating cooling fluids; Arrangements for circulating gas, e.g. air, within refrigerated spaces for circulating air, e.g. by convection
  • F25D17/06—Arrangements for circulating cooling fluids; Arrangements for circulating gas, e.g. air, within refrigerated spaces for circulating air, e.g. by convection by forced circulation
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25D—REFRIGERATORS; COLD ROOMS; ICE-BOXES; COOLING OR FREEZING APPARATUS NOT OTHERWISE PROVIDED FOR
  • F25D19/00—Arrangement or mounting of refrigeration units with respect to devices or objects to be refrigerated, e.g. infrared detectors
  • F25D19/003—Arrangement or mounting of refrigeration units with respect to devices or objects to be refrigerated, e.g. infrared detectors with respect to movable containers

Definitions

• the present invention is concerned with temperature control of container borne cargo in a ship's hold.
• each container with its own refrigeration unit for circulating cooled air through the container interior, and - 2 - with its own thermal insulation to minimise heat transfer from the container's surroundings.
• each such container 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.
• 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 - 3 - supplied through a ship borne system of ducting and connectors to the inlets of the containers themselves.
• 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.
• a directly expanded refrigerant typically Freon
• 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.
• 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.
• the present invention is intended to overcome or alleviate at least some of the shortcomings of the above described systems.
• apparatus for temperature control of container borne cargo in a ship's hold 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.
• gas is circulated through the containers and via the hold itself.
• 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.
• the thermal efficiency of the apparatus according to the present - 5 - 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
• the hold is at least substantially closed to die 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.
• an air freshening system may be provided.
• Such systems are used for controlling the level of pollutant gases - CO 2 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.
• 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.
• the air generated has 97V 2 % nitrogen.
• the gas distribution chamber is formed as a plenum chamber, its outlets comprising apertures in the chamber wall.
• 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.
• 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.
• 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. - 7 -
• a ship provided with apparatus according to the first aspect of the invention.
• a container for use with apparatus 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.
• a duct is defined immediately downstream of the inlet opening, the duct being shaped to promote flow of gas into the container.
• 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.
• 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.
• 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 - 9 - between the top of the stack and the container roof.
• 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.
• 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;
• - 10 - 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.
• 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 od er 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.
• die tank top (the horizontal surface forming the bottom of the hold) is labelled 4, while die 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 - 11 - bulkhead 10.
• die 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.
• 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).
• the distribution chamber 8 is enclosed by a horizontal partition 14, above which the space between the bulkhead 6 and die 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.
• a refrigeration/fan unit 19 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.
• 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 - 12 - through corresponding inlet openings 24 formed in the container walls.
• the ship's hold itself is d ermaily 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.
• an air freshening system (not illustrated) 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 C0 2 and ethylene.
• Fig. 3 illustrates the exterior of a container for use in the system being described.
• the container is of largely conventional construction, being - 13 - 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.
• Fig. 4 One feature which distinguishes die 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 ti at 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 die beam, and avoiding die 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.
• 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.
• a plenum chamber through which cooling air passes.
• the end face of d e container is formed by an upright, planar outer panel 38, and the plenum chamber 40 is formed between diis and an upright, planar inner panel 42.
• these two, - 14 - parallel, panels are separated by a distance corresponding to the depdi of a corner post 44 of the container framework.
• the inlet opening 24 to die plenum chamber 40 is formed as a circular hole in die outer panel 38 which communicates directly with die plenum chamber.
• die 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 die nozzle opening 22.
• die cooling air must traverse a short open space to enter the container. Nonedieless, it has been found experimentally that in die 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 die false bulkhead.
• fairings 48, 50 are provided within the plenum chamber 40 to form a shaped duct 52 - 15 - (most clearly seen in Fig. 5) through which air entering d e chamber passes.
• Both fairings are, according to die present invention, circular and concentric with die 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
• 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 witiiin the plenum chamber on a surface of the container's outer panel 38 and having a surface 52 which faces the fairing 48.
• the circular duct 52 formed by die two fairings acts analogously to a venturi, tending to promote airflow into the plenum chamber.
• the illustrated duct is circular, air flow through the duct being along roughly radial directions. Air leaves the duct dirough the circumferential opening 60, whose total area is approximately equal to die area of the inlet opening 24. In an intermediate region 62, the two fairings converge somewhat, forming a constriction in the duct. In diis region air velocity is increased and pressure is reduced, promoting air flow into the duct.
• radial vanes 64 connect the two fairings, and by virtue of downwardly curved outer portions 66, tend to deflect the air downwards - 16 - toward an exit aperture 54.
• air pressure within die ship's distribution chamber 8 is in the region of 300Pascals, while pressure in the container plenum chamber is in the region of lOOPascals.
• 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.
• 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.
• F . 7 illustrates an alternative construction of the container - 17 - nozzle, arrived at by development of me previously described nozzle and serving the same function, but considerably simplified in order to reduce manufacturing cost.
• die plenum chamber 100 is again formed between d e 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 die outer wall panel 102 and along its outer edge 115 to die planar portion 108.
• the planar portion 108 is maintained in position relative to the outer wall panel 102, spaced tiierefrom, by spacers 116 secured to both of these parts.
• Facing the fairing 106 within die plenum chamber is a planar, circular plate 118, secured to inner wall panel 104 irough spacers 120.
• the radial vanes 64 provided in die previously described embodiment to direct flow downward toward an exit from the container's plenum chamber are dispensed witi in die Fig. 7 embodiment.
• 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.
• 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 odier.
• baffles 138 Two baffles 138 are provided. Were it not for the baffles, a - 19 - direct route would be available for passage of air from the plenum chamber aperture 136, via d e passageway 134 and space 140 above die pallet stacks to the outlets 142 adjacent die container roof. Air would tiius escape from the container without circulating adequately irough the stacks.
• the baffles take the form of planar panels extending substantially die 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 die container roof and so do not obstruct the container interior, and the active position in which diey are seen in die 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 die inner edge of the stack.
• Handles (not illustrated) are provided to move the baffles upward to die 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 d e air passes instead from the passageway 136 dirough the pallet stacks and dien 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. - 20 - It is envisaged diat ships utilising die 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 die system is in transport of armaments such as ammunition and explosives.
• armaments such as ammunition and explosives.
• an atinosphere very high in Nitrogen and very low in Oxygen is required, and to provide diis a membrane filter is provided to filter the circulated atmosphere, reducing its oxygen content.
• containers 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.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• Physics & Mathematics (AREA)
• Thermal Sciences (AREA)
• General Engineering & Computer Science (AREA)
• Ocean & Marine Engineering (AREA)
• Devices That Are Associated With Refrigeration Equipment (AREA)

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Citations (7)

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• 1998
  • 1998-01-30 GB GB9801932A patent/GB9801932D0/en not_active Ceased
  • 1998-11-02 JP JP11539017A patent/JP2000515832A/ja active Pending
  • 1998-11-02 WO PCT/GB1998/003252 patent/WO1999038768A1/en active Application Filing
  • 1998-11-02 AU AU96387/98A patent/AU9638798A/en not_active Abandoned
  • 1998-11-02 DE DE19882297T patent/DE19882297T1/de not_active Withdrawn
  • 1998-11-02 PL PL98335943A patent/PL335943A1/xx unknown
  • 1998-12-07 GB GB9826709A patent/GB2333828B/en not_active Expired - Fee Related

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