Abstract:
A portable cryogenic cooling apparatus includes a platform; a tank for storing a cryogen and mounted to the platform; a heat exchanger operatively associated with the platform and in fluid communication with the cryogen; at least one air circulation device operatively associated with the heat exchanger for moving atmosphere therethrough; a first exhaust pipe in communication with the heat exchanger for removing gaseous cryogen from the heat exchanger to a location external to the atmosphere; a power source mounted to the platform and connected to the at least one air circulation device for powering said device; a control valve operatively associated with the tank and the heat exchanger to adjust an amount of the cryogen provided to the heat exchanger; and a controller in communication with the heat exchanger and the control valve for generating a signal to the control valve for operation thereof.

Description:
BACKGROUND 
       [0001]    The present inventive embodiments relate to apparatus and systems for transporting chilled or frozen products, such as food products, in trucks or other containers. 
         [0002]    Known transport systems for products such as food products rely upon diesel to fuel a compressor that circulates a refrigerant for chilling or cooling the products. Refrigerated carriers predominantly use mechanical systems to provide both chill and frozen transport. It is not uncommon that during times of peak flow when there is a high demand for refrigerated transport, truckers or other haulers do not have an adequate supply of suitable vehicles with installed refrigeration systems to transport the products. In addition, many of the known mechanical systems are constructed only to cope with small changes in the environment in which they operate or limited to operational designs when initially installed and adjusted with a particular container in which they are employed. During higher than normal ambient temperatures or when the temperature set point is reduced to a much lower level, or an increase in product is needed to be cooled, mechanical systems are usually unable to keep up with the demands for cooling that are required. 
         [0003]    Moreover, existing trucks, containers or other transport systems may only on occasion be required to transport chilled or frozen products for a short period of time. It may therefore not be cost efficient to have the container portion of the truck to be constructed with permanent fixtures for cooling and insulating the compartment. 
       SUMMARY OF THE INVENTION 
       [0004]    The present inventive embodiments provide a portable apparatus which is retrofitable to non-insulated or existing insulated vehicles or containers to convert a non-refrigerated space into a chilled or frozen space for transport of sensitive or perishable goods. The present apparatus permits the hauler, on short notice, to provide a refrigerated transport that will meet the customer&#39;s requirements and, where necessary, be able to increase the cooling efficiency of the container and alter a chilled transport container to a frozen transport container. The present apparatus also enables the hauler to convert a non-insulated van into a chilled transport apparatus by removably installing the present cooling apparatus and as necessary installing removably mountable insulation material at a side wall of the transport container. 
         [0005]    A portable cryogenic cooling apparatus is provided which includes a movable platform; a tank for storing a cryogen therein and being mounted to the platform; a heat exchanger operatively associated with the platform and in fluid communication with the cryogen stored in the tank; at least one air circulation device operatively associated with the heat exchanger for moving atmosphere through the heat exchanger; an exhaust pipe in communication with the heat exchanger for removing gaseous cryogen from the heat exchanger to a location remote from the atmosphere; a power source mounted to the platform and connected to the at least one air circulation device for powering said device; a control valve operatively associated with the tank and the heat exchanger to adjust an amount of the cryogen provided to the heat exchanger; and a controller in communication with the heat exchanger and the control valve for generating a signal to the control valve for operation thereof. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]    For a more complete understanding of the present inventive embodiments, reference may be had to the following drawing Figures taken in conjunction with the description of the embodiments, of which: 
           [0007]      FIG. 1  shows a schematic of a portable cryogenic cooling apparatus according to the present embodiments; 
           [0008]      FIG. 2  shows a schematic of an end view of the apparatus shown in  FIG. 1 ; 
           [0009]      FIG. 3  shows a schematic of a pipe and instrument diagram for the embodiment of  FIG. 1 ; 
           [0010]      FIG. 4  shows a schematic of another embodiment of a portable cryogenic cooling apparatus; and 
           [0011]      FIG. 5  shows the cryogenic cooling apparatus embodiment of either of  FIGS. 1 and 4  being removably positioned for use in a transport container. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0012]    Referring to  FIGS. 1-3 , a portable cryogenic cooling apparatus is shown generally at  10 . A schematic of a pipe and instrument diagram is shown in  FIG. 3  for the embodiment shown in  FIGS. 1 and 2 . 
         [0013]    The apparatus  10  includes a dolly  12  or similar type of wheeled platform having a plurality of sidewalls  14  arranged to provide an open ended side  16  in which a liquid cryogen tank  18  or vessel can be disposed. Liquid nitrogen (LIN), liquid carbon dioxide (CO 2 ) or liquid hydrogen can be stored in the tank  18 . By way of example only, LIN will be referenced herein, but other cryogens such as for example liquid CO 2  can be used as well. The tank  18  may be removably mounted to the dolly  12 . A forklift bracket  20  or stanchion is provided at an underside of the dolly  12  so that forklift arms (not shown) or tongs can be releasably engaged to the forklift brace to deposit the apparatus  10  in a compartment space  15 , truck or other container, and remove the apparatus from same. Upon placement of the apparatus  10  in the truck or container, such as shown in  FIG. 5 , the dolly  12  can be moved upon wheels  22  or casters to a select position in the truck. A handle  26  extends from one of the sidewalls  14  to maneuver the dolly  12 . 
         [0014]    A heat exchanger  28  is mounted to the dolly such as for example above the tank  18 . The heat exchanger has one end of its coil  29  in communication with a pipe  31  to the LIN in the tank  18 , while an opposite end of the coil extends to be in communication with an exhaust pipe  30  from the heat exchanger. The exhaust pipe  30  may be manufactured from a flexible material for example. At least one fan  32  is operatively associated with the heat exchanger  28  to draw the atmosphere in the space  15  across the heat exchanger coil for reducing the temperature of the space. 
         [0015]    A process logic controller (PLC)  34  includes a human machine interface (HMI)  36  therein and a temperature control sensor  38 . A control valve  40  controls the amount of liquid nitrogen that is removed from the tank  18  to the coil of the heat exchanger  28 . The PLC  34  interconnects the fans  32 , the temperature sensor  38  and the control valve  40 , as shown by broken lines  41 , to adjust the amount of nitrogen necessary to be removed from the tank  18  through the coil  29  of the heat exchanger  28  to meet the demands to reduce the temperature of the compartment space  15 . 
         [0016]    The tank  30  can, be way of example only, have a capacity of 200 liters (approximately 53 gallons). The exhaust pipe  30  can be manufactured from a flexible hose to vent nitrogen gas from the heat exchanger  28  to an area external from the compartment space  15 . An alarm (not shown) will signal a driver or user of the apparatus  10 , or for that matter anyone in the compartment space  15 , should for some reason nitrogen gas enter the compartment space and displace the breathable oxygen to a level insufficient to support life. 
         [0017]    The tank  18  can be filled either from a small liquid nitrogen delivery vehicle (not shown), or the user or customer of the apparatus  10  can use a small (perhaps on-site) cryogenic vessel having volume of for example 3,000 liters (approximately 793 gallons), mounted on a skid to top-up the tank. A pipe  54  is provided to introduce the liquid cryogen from the remote source (not shown) into the tank  18 . 
         [0018]    A battery pack  42  is self-contained and connected to the fans  32  and the controller  34 , as shown by broken lines  43  to provide power for the fans and the controller. The pack  42  may be removable mounted to the dolly  12 . The battery pack  42  may be of the rechargeable type or alternatively, the battery pack or the apparatus  10  may be connected directly to the vehicle electronics or work off a main power supply through an auxiliary socket (not shown). 
         [0019]    The total weight of the apparatus  10  may be for example approximately 150 kilograms (approximately 331 pounds), with the system manufactured from stainless steel and composite material such as carbon fiber. The apparatus  10  is a closed, indirect system for providing chilling or freezing to the products (not shown) in the compartment space  15 . That is, none of the liquid or gaseous nitrogen contacts the products, as said nitrogen gas is vented or exhausted external to the compartment space  15 . The tank  18  can be insulated with for example vacuum jacketing. 
         [0020]    The heat exchanger  28  may also include a heater  44  which, during maintenance, can be used to melt and remove condensate that has frozen to the coils of the heat exchanger. Since the heater  44 , shown for example in  FIG. 3 , will draw too much power to run continuously, the heater is run only when condensate accumulating on the coil of heat exchanger  28  renders the heat exchanger inoperative or inefficient, or when the apparatus  10  is removed from the compartment space  15 . 
         [0021]    In order to fill the tank  18  with the liquid cryogen, air or other gas must be displaced or removed from within the tank. Therefore, an exhaust line  60  or pipe having a valve therein is in communication with an interior of the tank  18  as shown in  FIG. 3  to remove displaced air in the tank therefrom. Another line  62  or pipe is in communication with the line  60  which is connected to a pressure relief valve  56  which will open when the pressure of air or gas within the tank  18  reaches a certain limit. The lines  60 , 62  are connected to a line  64  or pipe which extends to and is in communication with a further line  68  or pipe to exhaust the cryogenic gas from the compartment space  15 . 
         [0022]    Another line  57  or pipe branches off from the pipe  31 , and such line  37  has a pressure relief valve  58 . A line  66  or pipe extends from the pressure relief valve  58  and is in communication with the line  68  so that gas from the line  31  can ultimately also be exhausted from the compartment space  15  as shown in  FIG. 3 . The line  68  is in communication with the exhaust pipe  30  downstream of a valve  33 , which valve is disposed in the exhaust pipe  30  for exhausting the cryogenic gas from the heat exchanger  28 . 
         [0023]    Referring to  FIG. 4 , another embodiment of the portable cryogenic cooling apparatus is shown generally at  100 . The apparatus  100  includes the elements described above with respect to the embodiment of  FIGS. 1 and 2 , and also includes a hydrogen fuel cell  50  which is connected to the fans  32 , as shown by the broken lines  45 , to power same. Hydrogen gas for the fuel cell  50  is provided from the liquid hydrogen in the tank  18 . A pipe  46  or conduit has one end  47  in fluid communication with the tank  18 , and an opposite end  48  in fluid communication with the fuel cell  50 . The fuel cell  50  reduces the load on the battery pack  42 . 
         [0024]    In  FIG. 5 , either one or both of the portable cryogenic cooling apparatus  10 , 100  can be moved or positioned by being rolled into a container or housing mounted to a truck. The container or housing may be movably mounted to the truck. In this manner of construction, a container may be removed from the truck, with the apparatus  10 , 100  disposed therein, and loaded aboard a ship or barge for transport to a remote location, or stored as is aboard the ship or barge. When the apparatus  10 , 100  is disposed within the container at the select position, wheel locks (not shown) on the dolly  12  are actuated and/or the apparatus is lashed with known gear to an underlying surface to prevent movement of the apparatus within the container. 
         [0025]    The portable cryogenic cooling apparatus embodiment  10 , 100  described herein can be removably disposed within a shipping or truck, container upon very short notice. The apparatus is closed, i.e. a closed, indirect cryogen system such that none of the cryogen, such as liquid nitrogen or carbon dioxide, contacts the product, such as food products that are being chilled or frozen, or electronic equipment that is cooled, by airflow  52 . The apparatus  10 , 100  can be lifted into the container or on to the vehicle by a forklift and then further wheeled into the container to a select position. Exhaust from the apparatus  10 , 100  is vented through the vehicle&#39;s rear door or through a port or hole provided in a side wall of the container. 
         [0026]    The apparatus  10 , 100  can be used in work spaces where cooling is required for personnel or computer equipment. The apparatus can also be used where temporary cooling or chilling is required for other sensitive equipment. The cryogen used with the apparatus can be liquid hydrogen. Hydrogen gas can be used with the embodiment of  FIG. 4  to provide the necessary gas for the hydrogen fuel cell  50  to power the battery pack  42  for the fans  32  of the heat exchanger  28 . 
         [0027]    It will be understood that the embodiments described herein are merely exemplary, and that one skilled in the art may make variations and modifications without departing from the spirit and scope of the invention. All such variations and modifications are intended to be included within the scope of the invention as described and claimed herein. Further, all embodiments disclosed are not necessarily in the alternative, as various embodiments of the invention may be combined to provide the desired result.