Abstract:
A removable self-contained refrigeration unit is mounted within a vehicle, and is removable from a vehicle as a unit. The casing mounts both the evaporator and the condenser, and in one embodiment also mounts the compressor. With the embodiment that mounts the compressor, no refrigerant lines need be found anywhere except on the casing. The casing is removable from the vehicle as a one piece unit merely by connecting or disconnecting electrical connections. In a second embodiment the compressor is mounted remotely from the casing but the evaporator and condenser are still changeable as a one piece unit. In this embodiment a refrigerant connection need also be connected or disconnected to change the unit.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    This application discloses and claims a self-contained refrigeration unit that is designed to be installed in suitable receiving recesses in a truck or trailer refrigeration body. The refrigeration unit can be mounted entirely with a removable casing such that only electrical connections need be removed or attached to replace the unit, or in one embodiment some minor refrigerant connections may also need to be completed.  
           [0002]    So-called refrigeration trucks have a trailer or compartments that are cooled or refrigerated to preserve cargo, such as food stuffs. Typically, the various components of a refrigerant cycle are mounted into the truck separately and apart from each other. As a consequence of this configuration, a significant amount of tubing and electrical wiring is used to control and route the refrigerant between the components of the refrigeration system. This tubing and wiring prevents the easy installation and removal of these components, requiring significant labor and expense to connect and disconnect the components of the refrigeration system for installation or maintenance.  
           [0003]    For example, repair of the evaporator requires the disconnection of the evaporator from the truck trailer&#39;s refrigeration system and then removal of this particular component. While this component is repaired, the refrigeration system is rendered useless and the truck inoperable for refrigeration during the time of repair.  
           [0004]    Also, refrigerated trucks typically have the refrigerant circuit mounted in a box above the nominal top of the vehicle cabin. Space in this area tends to be crowded as a consequence of increased space for the driver.  
           [0005]    A need therefore exists for a refrigeration system that can be easily repaired without causing significant downtime in the use of the refrigeration truck.  
         SUMMARY OF THE INVENTION  
         [0006]    The present invention comprises a self-contained refrigeration unit that permits convenient installation and removal of the unit from a vehicle. Like existing refrigeration systems, the refrigeration unit comprises an evaporator, a condenser and a compressor. In contrast to such systems, however, the refrigeration unit localizes these refrigeration components on a casing of a standardized size to support the evaporator, condenser and compressor. This casing is tailored to fit a frame having an opening of about the same standardized size to receive the casing. The frame is part of the vehicle refrigeration compartment. Insulation is also provided between refrigeration components within the unit so as to promote their efficient operation. The entire refrigeration unit may be quickly and easily installed and removed from the vehicle as a modular unit by simply moving the casing in and out of the frame.  
           [0007]    In one preferred embodiment, the refrigerant flow of the refrigeration unit is entirely self-contained within the casing. In this configuration, the refrigeration unit may be installed without connecting refrigeration tubing to the unit and may be removed without disconnecting such tubing. To facilitate quick and easy installation and removal, the refrigeration unit also employs a power connector on the casing and a matching power connector about the frame of the vehicle so that the refrigeration unit may be quickly powered by plugging the connectors together. Also, the casing may have a control connector on the casing with a matching control connector on the frame. Thus, the entire refrigeration unit may be conveniently installed and removed on the vehicle without spending significant time making connections to operate the refrigeration unit.  
           [0008]    The unit may be placed in the roof of the vehicle compartment. The unit may also be placed on the walls of the compartment. It is also preferable that a seal be employed between the casing and the frame to insulate the vehicle compartment from ambient temperatures. A layer of the installation between the evaporator and condenser is also used.  
           [0009]    In a second embodiment, the compressor is powered by a power take off from the vehicle drive. In this embodiment, a simple check valve connection is placed on the casing such that the refrigerant may be routed to and from the compressor. The invention still facilitates the changing of the refrigeration unit should the evaporator or condenser fail.  
           [0010]    The modular nature of the refrigeration unit permits a number of units to be installed on a vehicle on one or multiple trailers. Each of these units may be controlled individually or separately by a control unit. A multiplex bus communication system may be employed to control each unit.  
           [0011]    The present invention also permits the storing of an inventory of refrigeration units all of about the same standard size. Accordingly, rather than repair a refrigeration unit on the vehicle, the malfunctioning refrigeration unit may be quickly and easily removed and replaced with another standardized refrigeration unit from inventory. The refrigeration unit may then be repaired without causing significant down time to the operation of the vehicle. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]    The various features and advantages of this invention will become apparent to those skilled in the art from the following detailed description of the currently preferred embodiment. The drawings that accompany the detailed description can be briefly described as follows:  
         [0013]    [0013]FIG. 1 shows an embodiment of the invention including refrigeration unit with casing and frame having an opening about the size of casing.  
         [0014]    [0014]FIG. 2 illustrates a side view of the embodiment of FIG. 1 including a control unit and power unit.  
         [0015]    [0015]FIG. 3 illustrates a cross-sectional view of the refrigeration unit of FIG. 1 and FIG. 2.  
         [0016]    [0016]FIG. 3A illustrates various power sources for the refrigeration unit.  
         [0017]    [0017]FIG. 3B illustrates a front view of the power sources of FIG. 3A.  
         [0018]    [0018]FIG. 4 illustrates a plan view of the refrigeration unit of FIG. 3.  
         [0019]    [0019]FIG. 5 shows another embodiment of the invention, employing a direct drive unit. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0020]    [0020]FIG. 1 illustrates truck  10  employing the invention. Shown are a self-contained refrigeration unit (SCU)  12  having casing  14  of a predetermined size and frame  22 , a casing mounting, on refrigeration compartment  19  having opening  17  of about the same predetermined size of casing  14  so as to receive casing  14 . Truck may have another vehicle refrigeration compartment  21  as well as additional refrigeration units  26  and  30 . Preferably, refrigeration units  12 ,  26 , and  30  have the approximate same predetermined size to permit their modular interchangeability and to reduce the required inventory or supply of spare refrigeration units.  
         [0021]    Because refrigeration unit  12  has casing  14  of approximately the same predetermined size as opening  17  of frame  22 , refrigeration unit  12  may be quickly and easily installed and removed onto vehicle refrigeration compartment  19 . Moreover, refrigeration unit  12  may be easily replaced by another refrigeration unit from an inventory so that the truck may continue to operate while refrigeration unit  12  is repaired.  
         [0022]    To promote the quick and easy installation of refrigeration unit  12 ,  26 , and  30 , the only connections that the invention requires to be made to operate the refrigeration units are electrical connections as can be understood from FIG. 2. Accordingly, refrigeration unit has first power connector  31 A on casing  14  that connects to second power connector  31 B and has first control connector  32 A on casing  14  that connects to second control connector  32 B. The connection of first power connector  31 A to second power connector  31 B powers refrigeration unit  12 . As described in greater detail below, such power may be provided by a drive unit  24 , an electrical generator on truck  10 , fuel cell, or other power source as known. In other words, each refrigeration unit  12 ,  26 , and  30  comprises a complete refrigeration system that only requires a suitable source of electrical power to operate. The connections are shown somewhat schematically here, but a worker in this art would be capable of providing appropriate connections.  
         [0023]    [0023]FIG. 3 shows refrigeration unit  12  having electric power control  52  to control electrical power to electrical elements, such as evaporator fan  54 , condenser fan  38 , compressor  46  and control unit  51 . Electric power control  52  may be a set of contractors and thermal relays or can be an electronic inverter to permit speed control of electrical motors.  
         [0024]    As shown in FIGS. 3A and 3B, power to electric power control  52  and other electric components of refrigeration unit  12  may be supplied by electric power supply system  98 . Generator  110  mechanically linked to truck engine  116  may provide electrical power as known. Alternatively, power can be provided by connections to generator  112  associated with alternator-starter on a truck engine, which is also commercially available. Additionally, power may be supplied by power module  100 , such as a hydrogen fuel cell or genset module, which provides power independently of the operation of truck engine  116 . Moreover, as shown below, power may be supplied by a direct drive unit.  
         [0025]    The connection of first control connector  32 A to second control connector  32 B permits refrigeration unit  12  to be controlled by the control unit  25 . Each of these refrigeration units  12 ,  26 , and  30  may also be controlled by the same control unit  25 . In such a network configuration, each unit may also be powered by the same source of power. Moreover, these units may be powered and operated by known multiplex bus communication systems.  
         [0026]    As shown in FIG. 4, each refrigeration unit  12  may also have its own control unit  51 , which may work in conjunction with control unit  25  or, independently, to control temperature within each compartment. Hence, refrigeration unit  12  may be linked on a network of refrigeration units or operate on its own. The network link may be through remote control or by bus as known. Thus, refrigeration unit  12  may work independently or in combination with other similarly linked units to control refrigeration. As a consequence, the effect of the failure of one such unit is greatly limited. Moreover, the separate control of each unit also permits the separate control of the temperature of each compartment.  
         [0027]    [0027]FIG. 3 illustrates the self-contained nature of refrigeration unit  12 . As shown in FIGS. 3 and 4, only electrical connections need be made because refrigeration unit  12  is a self-contained refrigeration unit that circulates refrigerant within casing  14 . Accordingly, there is no need to connect refrigerant tubing to refrigeration unit  12 . The refrigerant is preferably entirely contained within casing. Casing  14  supports evaporator  42  and compressor  46 . Casing  14  may also support condenser fan  38 , control unit  51 , condenser  34 , evaporator fan  54 , and other refrigeration components. As known, compressor  46  compresses a refrigerant and communicates this refrigerant to condenser  34 . Condenser fan  38  draws outside air over condenser  34  so as to remove heat from the refrigerant as shown at A. Refrigerant is then passed through an expansion valve, and then communicated to evaporator  42 . Air is drawn over evaporator  42  by fan  54  to cool vehicle refrigeration compartment  19 . In contrast to existing systems, refrigeration unit  12  contains all of the necessary elements for refrigeration in casing  14  of a predetermined size that matches opening  17  of frame  22 . Refrigerant is substantially communicated within the boundaries of casing  14  as well so that no refrigerant tubing need be connected to refrigeration unit  12  for operation.  
         [0028]    As seen in FIG. 3, casing  14  is set into frame  22  of refrigeration compartment  19 . Seal  100 , preferably a multilip gasket, is placed around casing  14  to allow good insulation and quick installation and removal. This type of seal is typically used on a truck refrigeration door and may be employed here. Casing  14  and seal  100  may be supported within frame  22  through support connections as known. Casing  14  is sufficient to support the weight of components and constructed so as to allow quick installation and removal of casing  14  in less than five minutes. Casing  14  is preferably a roof top unit that does not protrude above frame  22  so as to minimize air drag. The unit may also be placed on the walls of the truck trailer.  
         [0029]    To accomplish this goal, as shown in FIG. 3, casing  14  may have two compartments, compartment  35  and compartment  36 , separated by wall  37 , which is preferably temperature insulated. Compartment  35  has condenser  34 , condenser fan  38 , while compartment  36  has evaporator  42  and evaporator fan  54 . Compressor  46  may occupy space within wall  37  and may be horizontal to reduce the profile of casing  14 . Compartment  35  and compartment  36  are located virtually side-by-side to minimize the profile of casing  14  as well.  
         [0030]    Moreover, because refrigeration unit  12  is self-contained, a plurality of such units may be easily installed on vehicle refrigeration compartments  19  and  21  without the need to connect refrigeration tubing between the units. Indeed, only power connections and control connections are required.  
         [0031]    [0031]FIG. 5 shows the unit  14  having a refrigerant connection  15  for routing refrigerant to and from an external compressor  53 . In this instance, the external compressor  53  is powered by a direct drive unit  55 , such as a power takeoff from the vehicle, although the unit may be used as described above in a trailer and truck body. As is known, the compressor draws the most power requirements for a refrigerant cycle, and it may well be that in certain applications it would be desirable to have the compressor driven by the vehicle power takeoff, rather than separately powered from the vehicle power supply. Even so, by having the remainder of the refrigerant cycle mounted on the removable casing  14 , the present invention still facilitates the changing of the refrigerants unit. Only the simple electrical connections of the previous embodiment, plus the one simple refrigerant connection  50 , need be utilized. Preferably the refrigerant connection  50  would be provided with appropriate check valves on both sides such that any refrigerant in the casing and any refrigerant in the compressor at the time of change will not leak.  
         [0032]    The self-contained nature of refrigeration unit  12  as well as its standard size allow for the storing of multiple refrigeration units in an inventory. In this way, each refrigeration unit, such as refrigeration unit  12 , refrigeration unit  26 , and refrigeration unit  30  may be replaced by another refrigeration unit from inventory merely by disconnecting these units from their respective power and control connectors and removing the units from their locations. The FIG. 5 embodiment would also include the simple refrigerant connection  50  to be changed. Thus, a new unit may be installed simply by placing the refrigeration unit within opening such as opening  17  and making the necessary electrical connections to power and control the unit and perhaps a minor refrigerant connection in the FIG. 5 embodiment. This unit thus minimizes down time of vehicle  10 . Moreover, multiple self-contained refrigeration units simplifies multi-temperature and separate control of each refrigeration compartment because each compartment has its own unit with its own compressor that independently cools each compartment. Also, multiple compressors permits one at a time powering of each compressor, reducing the voltage drop and current rush experienced by the truck.  
         [0033]    The electrical connections can be provided on a network including both a power and control line. The electrical power system could be a set of contactors and thermal relays or could be an electronic inverter to allow all of the actuators to have speed control. The invention also facilitates the use of multi-temperature applications across several compartments. Achieving a multi-temperature application is made easier by this invention since each compartment may be individually controlled by its own refrigeration unit. Further, by having the several distinct compressors, a power generator for the system can be relieved since the compressors could be started one at a time, and therefore the electrical starting power necessary could be decreased.  
         [0034]    The evaporator fan can be any type of axial or centrifugal fan. The fan can be mounted as shown schematically in the figures, or could be mounted transverse. The compressor may be any type of compressor, although it is preferred it be a horizontal compressor. The horizontal compressor serves to minimize the height of the refrigeration unit. More preferably a rotary compressor, and even more preferably a scroll compressor is utilized. Horizontal rotary or scroll type compressors generally have a smaller size, weight, and relative cost then other compressors.  
         [0035]    The aforementioned description is exemplary rather that limiting. Many modifications and variations of the present invention are possible in light of the above teachings. The preferred embodiments of this invention have been disclosed. However, one of ordinary skill in the art would recognize that certain modifications would come within the scope of this invention. Hence, within the scope of the appended claims, the invention may be practiced otherwise than as specifically described. For this reason the following claims should be studied to determine the true scope and content of this invention.