Classifications

• • 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
  • F25D3/00—Devices using other cold materials; Devices using cold-storage bodies
  • F25D3/10—Devices using other cold materials; Devices using cold-storage bodies using liquefied gases, e.g. liquid air
  • F25D3/105—Movable containers
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60H—ARRANGEMENTS OF HEATING, COOLING, VENTILATING OR OTHER AIR-TREATING DEVICES SPECIALLY ADAPTED FOR PASSENGER OR GOODS SPACES OF VEHICLES
  • B60H1/00—Heating, cooling or ventilating devices
  • B60H1/32—Cooling devices
  • B60H1/3202—Cooling devices using evaporation, i.e. not including a compressor, e.g. involving fuel or water evaporation
• • 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
  • F25D11/00—Self-contained movable devices, e.g. domestic refrigerators
  • F25D11/003—Transport 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
  • F25D29/00—Arrangement or mounting of control or safety devices
  • F25D29/001—Arrangement or mounting of control or safety devices for cryogenic fluid systems

Definitions

• the present invention relates to the field of transport and distribution of thermosensitive products, such as pharmaceuticals and foodstuffs.
• thermosensitive products such as pharmaceuticals and foodstuffs.
• the cold required to maintain the temperature of the products is provided mainly by two different technologies:
• cryogenic groups operating in an open loop and implementing an indirect or indirect injection of cryogenic fluids into the space containing the products.
• the present invention is more particularly concerned with cryogenic indirect injection solutions.
• the cryogenic fluid (the most used are liquid nitrogen and liquid CO 2 ) is conveyed from an onboard cryogenic tank, usually under the refrigerated truck, to one or more heat exchangers located at the same time. Inside the cold rooms of the truck, exchangers equipped with air circulation means. These exchangers allow the cooling of the internal air to the chamber storing the products, air surrounding the exchangers, to the desired temperature.
• the heat extracted from the air allows, first of all, a complete evaporation of the cryogenic fluid flowing in the exchanger, then an increase in its temperature to a temperature close to that of the chamber.
• the cryogenic fluid exiting the exchanger is then rejected outside after giving up a maximum of cooling energy.
• the heat exchange is not optimized, especially during the transitional phase during which the chamber has not yet reached its target temperature (lowering or temperature rise): an insufficient exchange surface, a flow rate of the bridged cryogen, poor distribution of the cryogen flow rate in the various modules of the exchangers used or poor distribution of the air side can be at the origin of such performance defects of the exchangers during this phase.
• phase 1 full load
• phase 2 partial load
• the temperature of the air in the enclosure (also called “box” or “chamber”) to be cooled is much higher than the set temperature.
• the instructions traditionally practiced in this transport industry we can cite the example of a set point of 0 to 4 ° C for the transport of fresh products, while we meet instructions of -20 ° C for the transport of frozen products, these two instructions can be implemented in two neighboring rooms of the same cam ion.
• the valves regulating the cryogen injection then open completely and remain open to allow heat exchange between the cold walls of the heat exchanger where the cryogen circulates and the surrounding air, air which sees its temperature decrease as and when measure until it is close to the set temperature.
• a regulation of the valves begins to impose more or less long closing times in order to gently "land" the temperature of the air internal to the enclosure in the vicinity of the set temperature, and to maintain this temperature for the rest of the time.
• this control is performed so as to maintain the "pinch” at a fixed value, preferably in the range of 5 to 20K and this regardless of the system operation phase (fast descent or maintenance) .
• the present invention therefore particularly aims to provide a new process control governing the operation of such indirect injection transport, to allow the system to operate optimally during all phases of operation.
• the present invention proposes in particular a solution for regulating the temperature of the cold room by optimizing the heat exchange and improving the performance of the exchangers, in particular by increasing the cooling capacity provided. during the rapid descent phase.
• the present invention proposes the taking into account of a parameter allowing the regulation of the nip of the exchanger, a parameter which is variable according to the temperature reached by the air of the enclosure to be cooled.
• the objective is therefore to have a large difference between the outlet temperature of the cryogen and the temperature of the air internal to the chamber, as long as the latter is not close to its target temperature.
• a greater supply of the exchanger is promoted in cryogenic fluid and consequently a much higher power output.
• the air temperature approaches the set temperature the energy demand is less important because the volume of air and the walls of the truck have been cooled and their thermal inertia has been largely overcome at this stage. of operation, and one can then afford to maintain a higher cryogen output temperature and thus a gap (pinch) between the indoor air temperatures at the chamber and cryogen output that can be reduced.
• the present invention thus relates to a method for transporting thermosensitive products in a refrigerated truck, of the type where the truck is equipped with:
• cryogenic fluid such as liquid nitrogen (or any other liquefied cryogenic fluid)
• an air circulation system for example of the fan type, capable of bringing the air inside the chamber into contact with the cold walls of the heat exchanger system
• a management and control unit able to regulate the internal temperature Tj nt to a setpoint value T con s by ordering a closing or opening, or the degree of such opening / closing, of one or valves supplying cryogenic fluid to the exchanger system;
• the or each of the valves supplying cryogenically the exchanger system are of the "TOR" type and the regulation according to the invention then orders the total opening of this or these valves. as long as the Pinch is less than or equal to the parameter P.
• valves including proportional valves whose possibilities of action are obviously more numerous, in which case the regulation according to the invention then orders, according to the algorithm used, as long as the pinching is less than or equal to the parameter P, the wide or total opening of this or these valves or the increase of their opening according to the moment considered within this phase.
• the management and control unit orders the closing of the valve or valves supplying the exchanger system, or the reduction of their opening according to the moment considered within of this phase and again according to the algorithm chosen to govern the operation of the regulation:
• the or each of the valves supplying cryogenically the exchanger system are of the "TOR" type and the regulation according to the invention then orders the total closure of this or these valves when Pinching goes over the P parameter.
• the or each valve supplying the exchanger system are valves proportional, and the regulation according to the invention then orders, according to the algorithm used, when the pinching passes above the parameter P, the partial closure, or total, or the reduction of the opening of this or these valves according to the moment considered within this phase.
• Tsortie fluid but on the contrary to vary it according to the value of ⁇ , ie according to the position of the temperature inside the chamber with respect to a setpoint, therefore according to the need of frigories necessary for the phase of life of the transport considered (phase fast descent, maintenance phase).
• a nip which is reduced abruptly when the internal temperature is a few degrees from the set point, preferably less than 2K;
• a nip is kept constant when the internal temperature reaches its set temperature.
• FIG. 2 represents the two temperature descent curves obtained in the chamber, according to the regulations currently practiced (curve m)) and according to the invention (curve n)).
• FIG. 3 represents the two curves of power supplied (in W) as a function of time, according to the regulations currently practiced (curve o)) and according to the invention (curve p)), the hatched part materializes the difference in power supplied. according to the invention, especially during the first stages of the rapid descent.
• the invention as just described applies to the case of a single chamber within a truck but also to the case of several storage chambers. products within a truck, and the invention then makes it possible to regulate the temperature within each of the chambers, each of the chambers being equipped with an exchanger system, each of the chambers having to respect its own internal setpoint T con according to the products it has to store, the control system measuring in real time the internal temperature of each chamber " Tint, that of cold vapors coming out of all or part of the exchangers of the exchanger system of each chamber (T SO fluid part) > the Pinching associated with each chamber, etc.

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

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• 2012
  • 2012-04-18 FR FR1253546A patent/FR2989763B1/fr active Active
• 2013
  • 2013-02-22 CA CA2870533A patent/CA2870533C/fr active Active
  • 2013-02-22 US US14/395,213 patent/US9797645B2/en active Active
  • 2013-02-22 AU AU2013250994A patent/AU2013250994A1/en not_active Abandoned
  • 2013-02-22 EP EP13710506.0A patent/EP2839227B1/fr not_active Not-in-force
  • 2013-02-22 WO PCT/FR2013/050366 patent/WO2013156696A1/fr not_active Ceased
  • 2013-02-22 JP JP2015506276A patent/JP6193357B2/ja active Active

Patent Citations (3)

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