DK170581B1 - Method and device for air distribution in cargo spaces - Google Patents

Description

DK 170581 B1

Field of the Invention The present invention relates to a method of air distribution in cargo spaces and a device for carrying out the method. In particular, the invention is intended to be used for supplying cooling air to a load in a cold storage room of a cooling vessel and, above all, to cold storage rooms without a floor rack.

State of the art In modern refrigeration vessels, mechanical 10 air circulation systems are usually used, where cooled air is forced through the load in the cooling load compartment in order to maintain a proper load temperature. In refrigerated cargo compartments, always aim for as even air distribution as possible, in order not to damage or destroy the cargo. The cargo may be packed in cartons which may be stowed on pallets. In conventional air circulation systems, floor grilles with holes are preferably used to distribute the cooling air in the cargo space, the load being on pallets or directly on the grate and the circulating air is first forced horizontally below the floor grate 20 and then vertically from the floor grate through the cargo, for example, fruit cartons. Known air circulation systems usually provide a constant flow of air under the grate or grilles. A relatively good distribution of the cooling air can be obtained from a well-dimensioned grid.

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Disclosure of the Invention

In order to better distribute and optimize the supply of air under a load on pallets, such as cooled air to refrigerated load space with load on pallets, even for systems without grating, where the air is blown directly under the pallets, a method of air distribution and a device for which the method and device of the air throw length of the air flow supplied under the pallets can be varied. In systems with no air supply air directly under the pallets, an uncontrolled pressure drop is always obtained in different parts of the cargo space, depending on how the cargo DK 170581 B1 2 'is stowed and how the pallets are designed.

By controlling the fan capacity by, for example, a frequency converter or the like, a variable pulsating air flow of variable air throw length, periodic variations of throw length or otherwise varying throw length with or without interruption for the resulting air flow under the pallets can be obtained. which can optimize the air distribution under the cargo pallets in the cold room, thereby effectively preventing certain zones in the cargo 10 from getting too little or being completely without air supply.

Fiaurbeskrivelse

FIG. 1 shows a simplified sectional view of a cargo compartment in a refrigerated vessel with a device according to the invention for distributing cooled air to cargo on pallets.

FIG. 2 shows the time relationship between a incoming frequency, b outgoing frequency and c resulting air flow and fan pressure from fans.

Description of Embodiment Example In FIG. 1 is shown in a simplified sectional view of how several electric powered air circulation fans 1 are placed over one another in connection with air ducts behind a cargo hold wall in a cooling vessel. With the fans 1, cooled air is supplied to 25 air ducts 2 and further under pallets 3 with cargo between a cargo floor 8 and the pallets 3. With arrows 9 it shows how cooled air flows from the ducts 2 to the space 7 between the cargo pallets 3 and the cargo room floor 8. a resultant pulsating flow such as an air throw from the blowers 1. The pulsating air flow is provided by the blowers 1 which are speed controlled by a frequency converter 5. A period and sequence control means - a regulator and control unit 6 which can be automatic or manually set to output control signals, transmits a control signal suitable for the frequency converter 5 to operate the air circulation fans 1. Depending on the load structure and load content, with knowledge of appropriate storage temperature and detection of current cargo temperature, with the aid of the control unit 6, an appropriate rpm variation is provided with a resultant 5 variable pulsating air flow and a suitable air-throw length below the pallets to optimize the cooling air distribution at a temperature correct for the load content.

In FIG. 2 shows the relationship between a incoming frequency, b outgoing frequency and c resulting air flow 10 and fan pressure from the fans related to a time factor. The resulting variably pulsating air flow from the fans 1 then, when passing through the air duct 2 and below the pallets 3 in the space 7 between the pallets 3 and the cargo floor 8, results in air throws 4, 15 which are shown in FIG. 1, the length of the air throw thus varying depending on the control signals from the control unit 6.

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Claims (4)

4 DK 170581 B1 A method for distributing air to load on * pallets in cargo spaces, for example, for distributing cooling air to cargo on pallets in the cooling load compartment of a cooling vessel, characterized in that one or more fans (1) are driven to deliver a variable pulsating air flow , thereby providing a variable air throw length (4). 2. A method according to claim 1, characterized in that the air flow from the fans is conducted from an air duct (2) to a space (7) between cargo pallets (3) and a cold room floor (8). Device for distributing air for cargo in cargo space, for example for distributing cooling air for cargo on pallets in the refrigerated cargo compartment, characterized in that one or more blowers (1) are arranged to supply a variable pulsating air flow to the cargo in the cargo space. , to get a variable air throw length. Device according to claim 3, characterized in that a control unit (6) is arranged to output a 20 or more control signals to a frequency converter (5) for variable control of the rpm of one or more blowers (1) to obtain a variable pulsating air flow to the load. δ