Abstract:
A pet shelter divided into a plurality of compartments of different interior temperatures with a temperature control device for controlling the temperature in the pet shelter, such that the interior temperatures change progressively across the compartments to blend into the temperature of the outside environment.

Description:
TECHNICAL FIELD 
       [0001]    This invention relates to a pet shelter, in particular, a temperature controlled pet shelter. 
       BACKGROUND 
       [0002]    It is common that a pet lives in an environment of climate very different from where it originates, for example, the temperature may be much higher or lower, or the humidity is much higher than that what is suitable for the pet. It is crucial to maintain the condition, such as room temperature or humidity, in the interior of a pet shelter to make it suitable for the pet. 
         [0003]    The pet house of US Patent Publication No. US 2005/0056232 A1 discloses a pet house containing a thermoelectric cooler. However, when the pet passes between the interior of the pet house and the outside environment, the sudden change of temperature or humidity experienced by the pet causes health problems. For example, the pet may catch cold, or suffer from skin infection. Such health problems may be avoided if the temperature difference experienced by the pet from passing between the pet house and the outside environment can be much reduced. 
         [0004]    A thermoelectric module is a common cooling or warming device used in a temperature controlled pet shelter. However, it is often not very efficient as it contains a hot side and a cold side in close proximity, while one side affects the performance of the other side. For example, if a cold side is used to cool off the interior of the pet house, the heat generated on the hot side and dissipated from the corresponding heat sink will increase the temperature of the cold side and the cold heat sink, affecting the cooling performance. 
         [0005]    In the above example, there should be a way to further reduce the temperature of the heat sink on the hot side so that the heating effect on the cold side and the cold heat sink can be reduced. 
       SUMMARY OF THE INVENTION 
       [0006]    An object of the present invention is to reduce the temperature difference experienced by a pet when passing between the interior of a pet shelter and the outside environment. 
         [0007]    An embodiment of the present invention provides a compartment of a transitional temperature between a temperature controlled compartment and the outside environment. 
         [0008]    Another embodiment of the present invention contains an air deflecting device for deflecting the airflow generated by a temperature control device from directly entering into a transitional compartment. 
         [0009]    Another embodiment of the present invention contains a temperature control device which generates an airflow against a frame separating two compartments for deflecting the airflow from directly entering into the transitional compartment. 
         [0010]    Another embodiment of the present invention contains a temperature control device which generates an airflow against the roof and a frame having a top portion in connection with the roof for deflecting the airflow from directly entering into a transitional compartment. 
         [0011]    Another embodiment of the present invention contains a thermoelectric module having heat sinks separated by a sufficient distance to reduce the heating effect therebetween. 
         [0012]    Another embodiment of the present invention contains a thermoelectric module having heat sinks separated by a thermal insulator to reduce the heating effect therebetween. 
         [0013]    Another embodiment of the present invention contains a collector for collecting the water condensed in a first heat sink, the water collected being used for cooling a second heat sink. 
         [0014]    Another embodiment of the present invention contains a first heat sink having a lower end at a higher level with respect to a lower end of a second heat sink, and a collector for collecting the water condensed in a first heat sink, having an upper end below the first heat sink and a lower end below a second heat sink, such that the condensed water is collected and flows to the lower end of the second heat sink for cooling the second heat sink. 
     
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0015]    The above and other aspects, features, and advantages of the present invention will become more apparent upon consideration of the following detailed description of preferred embodiments, taken in conjunction with the accompanying drawing figures, wherein:— 
           [0016]      FIG. 1  is a perspective front view of a pet shelter in accordance with an embodiment of the present invention; 
           [0017]      FIG. 2  is a perspective front view of the pet shelter of  FIG. 1  without showing the roof and the side walls; 
           [0018]      FIG. 3  is a perspective view of a frame of the pet shelter of  FIG. 1 ; 
           [0019]      FIG. 4  is a sectional view of the two compartments of the pet shelter of  FIG. 1  showing the circulation of airflow therein; 
           [0020]      FIG. 5  is an explosive view of the back wall and the temperature control device in accordance with an embodiment of the present invention; 
           [0021]      FIG. 6  is a sectional view of the temperature control device of  FIG. 5 ; 
           [0022]      FIG. 7  is a sectional view of the temperature control device of  FIG. 5  showing the direction of airflow therethrough; 
           [0023]      FIG. 8  is a sectional view of the temperature control device of  FIG. 5  showing the flow of the condensed water therein; 
           [0024]      FIG. 9  is a perspective back view of the pet shelter of  FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The Structure of Pet Shelter 
       [0025]    As illustrated in  FIGS. 1 and 2 , a preferred embodiment of the present invention is a pet shelter [ 10 ] containing a first compartment [ 80 ] and a second compartment [ 90 ]. A housing [ 20 ] of the pet shelter [ 10 ] includes a roof [ 22 ], two side walls [ 24 ], a floor [ 26 ], a door frame [ 50 ], a middle frame [ 60 ] and a back wall [ 70 ]. 
         [0026]    As shown in  FIG. 3 , the door frame [ 50 ] and the middle frame [ 60 ] each has a projection [ 32 ] at each bottom end for coupling to a corresponding slot [ 27 ] on the side of the floor [ 26 ]. The floor [ 26 ] having a front and a back further contains a groove [ 34 ] at the back with sufficient depth for receiving and supporting the bottom of the back wall [ 70 ]. A tray [ 28 ] is placed on the floor [ 26 ] for receiving the droppings of the pet, which is removable for the disposal of droppings and cleaning. 
         [0027]    The roof [ 22 ] is attached to the top of the door frame [ 50 ], the middle frame [ 60 ] and the back wall [ 70 ], for example, by a hook-and-loop fastener [ 42 ] or Velcro-type tape, so that the housing can be easily assembled. The roof [ 22 ] and the side walls [ 24 ] may be soft cushioned layer made of insulating material such as cotton. The side walls [ 24 ] may be attached to the bottom of the roof [ 22 ] and the sides of the door frame [ 50 ], the middle frame [ 60 ] and the back wall [ 70 ] by hook-and-loop fasteners. 
         [0028]    The door frame [ 50 ] contains an entry [ 52 ] for the ingress and egress of the pet. The door frame [ 50 ] may contain a double layer of curtain [ 54 ] for trapping air in between to provide better insulation, which also defines the entry [ 52 ]. By way of example, the curtain [ 54 ] may be made of plastic. 
         [0029]    A temperature control device [ 100 ] is mounted on the back wall [ 70 ] for maintaining a temperature warmer or cooler than that of the outside environment. As illustrated in  FIGS. 2 and 4 , the middle frame [ 60 ] divides the pet shelter [ 10 ] into the first compartment [ 80 ] and the second compartment [ 90 ], with an opening [ 62 ] for the pet to pass between. The first compartment [ 80 ] serves as a transitional compartment with an intermediate temperature zone between the second compartment [ 90 ] and the outside environment. 
         [0030]    The temperature control device [ 100 ] generates a warm or cool airflow into the second compartment [ 90 ] for maintaining a suitable temperature for the pet. As shown in  FIG. 4 , in the preferred embodiment, an upward airflow is generated toward the roof [ 22 ] before circulating around the second compartment [ 90 ]. An air deflecting formation [ 66 ] is formed on the middle frame [ 60 ] for deflecting the airflow from directly entering into the first compartment [ 80 ]. In this embodiment, the air deflecting formation [ 66 ] is an arch formed on the top portion of the middle frame [ 60 ] to deflect the airflow along the roof [ 22 ]. The air deflecting formation [ 66 ] may be of another shape at another position on the middle frame [ 60 ] depending on the direction of the airflow from the temperature control device [ 100 ]. 
         [0031]    The deflected airflow circulates around the second compartment [ 90 ] and induces the air circulation in the first compartment [ 80 ]. Although air diffuses from the second compartment [ 90 ] to the first compartment [ 80 ], the airflow is prevented from directly flowing into the first compartment [ 80 ], which creates a difference in temperature between the two compartments. 
         [0032]    The temperature control device [ 100 ] is not restricted to a device which generates an airflow. For example, if a radiant heater is used as the temperature control device, the middle frame [ 60 ] may be made of an insulated material with a smaller opening [ 62 ] such that the middle frame forms an insulated wall between the two compartments to provide an intermediate temperature zone in the first compartment [ 80 ]. 
       Temperature Control Device 
       [0033]    As illustrated in  FIGS. 5 ,  6  and  7 , the temperature control device [ 100 ] is placed in a case [ 102 ] integrated with the back wall [ 70 ]. A cover [ 103 ] is attached to the case [ 102 ] on the side associated with the outside environment. 
         [0034]    The temperature control device [ 100 ] includes a thermoelectric module [ 150 ] disposed between a first heat sink [ 115 ] and a second heat sink [ 125 ]. The thermoelectric module [ 150 ] causes a temperature differential between a hot side and a cold side when an electric current is applied across the device. When the direction of the current is reversed, the hot side and the cold side of the thermoelectric module [ 150 ] are reversed. Thus, the thermoelectric module [ 150 ] may be used for warming or cooling the pet shelter [ 10 ] by adjusting the current applied. 
         [0035]    The first heat sink [ 115 ] is associated with the interior of the pet shelter [ 10 ] and the second heat sink [ 125 ] is associated with the outside environment. The heat sink is a metal device which absorbs and releases heat from the thermoelectric module [ 150 ] in its contact. The heat sink may a flat vertical surface and an array of fins protruding from the surface to provide a large surface area for heat dissipation. 
         [0036]    The thermoelectric module [ 150 ] works more efficiently if the heating effect between the first heat sink [ 115 ] and the second heat sink [ 125 ] can be reduced by separating the two heat sinks apart from each other. The heating effect includes the warming effect affected by a warmer heat sink on a cooler heat sink and the cooling effect vice versa. As such, a thermal conductor [ 155 ] is further disposed between the two heat sinks to keep the second heat sink [ 125 ] thermally connected with the thermoelectric module [ 150 ]. The thermal conductor [ 155 ] may be an aluminum block. 
         [0037]    A thermal insulator [ 160 ] substantially enclosing the thermal conductor [ 155 ] is disposed between the two heat sinks to provide further insulation in between and prevent heat loss from the thermal conductor [ 155 ] and the thermoelectric module [ 150 ]. 
         [0038]    The thermal insulator [ 160 ] may be made of a foam material and is positioned at a distance, for example about 3 mm, away from the heat sink to avoid the thermal insulator [ 160 ] being damaged by the heat sink and to reduce the heating effect from the heat sink on the thermal insulator [ 160 ]. Such arrangement increases the surface area exposed to air on the first heat sink [ 115 ] and the second heat sink [ 125 ] for the release of heat. 
         [0039]    As illustrated in  FIG. 7 , a first fan [ 110 ] and a second fan [ 120 ] are placed before the first heat sink [ 115 ] and the second heat sink [ 125 ] respectively for generating airflow through the heat sinks. The case [ 102 ] contains a first vent [ 117 ] and a second vent [ 127 ] on the cover [ 103 ] for the airflow to enter into the second compartment [ 90 ] and the outside environment. 
         [0040]    The first heat sink [ 110 ] may provide a cooling or warming effect depending on the direction of current applied on the thermoelectric module [ 150 ], while the second heat sink [ 120 ] will have the opposite effect. The second fan [ 120 ] drives air through the second heat sink [ 125 ] and reduces the heating effect on the first heat sink [ 115 ]. 
         [0041]    On each side of the case [ 102 ], a safety shield [ 164 ] is provided for preventing the contact of the fan by the pet, and a filter [ 162 ] is provided to filter dust in the air driven by the fan into the heat sink. 
         [0042]    The first heat sink [ 115 ] also functions as a dehumidifier when providing the cooling effect, as the cold first heat sink [ 115 ] causes the vapor in the air to condense into water on the surface of the first heat sink. The bottom [ 105 ] of the case [ 102 ] has a higher end portion [ 104 ] in  FIG. 8  below the first heat sink [ 115 ] and a lower end portion [ 106 ] below the second heat sink [ 125 ]. The higher end portion [ 104 ] collects the condensed water from the first heat sink [ 115 ]. The condensed water flows from the higher end portion [ 104 ] to the lower end portion [ 106 ] of the case bottom [ 105 ]. 
         [0043]    The lower end [ 126 ] of the second heat sink [ 125 ] is positioned near the lower end portion [ 106 ] of the case bottom [ 105 ] to be in contact with the condensed water flowing across. The condensed water serves to carry the heat away from the warm second heat sink [ 125 ], thus reducing the heating effect on the first heat sink [ 115 ]. A drain outlet [ 109 ] is provided at the lower end portion [ 106 ] for draining the condensed water out of the case bottom [ 105 ]. 
         [0044]    In another embodiment, the case bottom [ 105 ] is tilted so that the condensed water flows from the first heat sink [ 115 ] toward the second heat sink [ 125 ]. 
         [0045]    As shown in  FIG. 5 , the back wall [ 70 ] may contain two portions [ 72 ,  74 ] with a space provided in between to trap air for insulation. As shown in  FIGS. 5 and 9 , a drainage tube [ 190 ] connects the drain outlet [ 109 ] to a water tank [ 210 ] attached to the back wall [ 70 ] for collecting the condensed water. A ventilation fan [ 220 ] is mounted on the back wall [ 70 ] for providing ventilation in the pet shelter [ 10 ]. 
         [0046]    An electronic control unit [ 230 ] is connected to the temperature control device [ 100 ] for the user to set a temperature to be maintained in the second compartment [ 90 ]. The electronic control unit [ 230 ] controls the current passing through the thermoelectric module to adjust the warming or the cooling effect of the temperature control device [ 100 ]. 
         [0047]    There may be more than two compartments and they are not restricted to be on the same level. In another embodiment, the pet shelter [ 10 ] is divided into more than two compartments. In a further embodiment, the compartments are arranged on different levels. 
         [0048]    While the invention has been described in detail with reference to disclosed embodiments, various modifications within the scope of the invention will be apparent to those of ordinary skill in this technological field. It is to be appreciated that features described with respect to one embodiment typically may be applied to other embodiments.