Abstract:
A passage structure for an air compressor mainly has a trough extended from inside of a casing that communicates with a second space to increase the contact area of air and the casing. The trough has an outer surface with a plurality of cooling fins located thereon to enhance total heat dissipation effect. The trough forms an additional space to increase air capacity and can reduce noise during compression operation.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to a passage structure for an air compressor and particularly to a structure that can increase heat dissipation efficiency and reduce noise during operation of the air compressors. 
         [0003]    2. Description of the Prior Art 
         [0004]    The rapid progress of society mainly results from people&#39;s constantly pursuing a better quality of life. Many new products have been developed and introduced to meet this requirement. Compressor is one of such products. The constant innovation of people has greatly expanded the application scope of the compressor. 
         [0005]    The conventional compressor still has problems during operation, such as generating high air temperature and noise. During compression process of air, the pressure provided by the compressor usually is greater than the upper compressible limit of the air. To reach balance, the air temperature has to rise. But excessive high temperature tends to accelerate wearing of facilities and shorten service life. If the air is to be used by human being, people will feel uncomfortable. On the other hand, not only the machine generates a noise during operation, but also the air compression dose. The noise makes users uncomfortable and reduces the quality of using the machine. 
         [0006]    In short, to satisfy the rapid change pace of the modern society, the problems of the compressor have to be resolved. The present invention aims to practice this issue. 
       SUMMARY OF THE INVENTION 
       [0007]    The primary object of the present invention is to provide a passage structure for an air compressor so that air and casing have a larger contact area and the casing has a plurality of cooling fins and a trough to increase total heat dissipation efficiency. 
         [0008]    Another object of the invention is to provide a second space in the casing for guiding compressed air flow and a trough to increase the housing space thereby to reduce noise during air compression operation of the compressor. 
         [0009]    The passage structure for an air compressor of the invention is fastened to a compressing unit. The heat dissipation structure includes a upper casing and a lower casing, two spaces located in the casing to form a first space and a second space, and four ports formed on the casing, namely a first port, a second port, a third port and a fourth port. The first port and the second port are communicated through the first space. The first space communicates with the exterior through the first port and the second port. The third port and the fourth port are communicated through the second space, and the second space communicates with the exterior through the third port and the fourth port. A trough for housing is formed in the lower casing by extending an inner surface thereof. The trough communicates with the second space. A plurality of cooling fins are formed by extending the outer surface of the trough to increase heat dissipation efficiency and reduce noise. 
         [0010]    The foregoing, as well as additional objects, features and advantages of the invention will be more readily apparent from the following detailed description, which proceeds with reference to the accompanying drawings. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]      FIG. 1  is an exploded view of a first embodiment of the invention; 
           [0012]      FIG. 2  is a perspective view of the first embodiment of the invention; and 
           [0013]      FIG. 3  is an exploded view of a second embodiment of the invention. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0014]    Refer to  FIGS. 1 and 2  for a first embodiment of the invention. The passage structure for an air compressor of the invention is fastened to a compressing unit  10 . The passage structure includes a casing  20 , two spaces including a first space  30  and a second space  32 , four ports including a first port  40 , a second port  42 , a third port  44  and a fourth port  46 , a trough  50  and a plurality of cooling fins  52 . 
         [0015]    The compressing unit  10  has a compression chamber  12 , communicated with the exterior through an air suction port  14  and an air discharging port  16 . The casing  20  includes an upper casing  22  and a lower casing  24  interposed by a washer  60  to form an airtight sealing effect to prevent air from flowing out through the gap between the upper casing  22  and the lower casing  24 . The washer  60  has a plurality of vents  62  to allow the second space  32  formed between the upper casing  22  and the lower casing  24  to become communicable. The first space  30  and second space  32  are formed in the casing  20  in a ditch and/or trough manner on the upper casing  22  and/or lower casing  24 . The first port  40  and the second port  42  are formed respectively on the upper casing  22  and the lower casing  24 , and are communicated through the first space  30 . Thereby the first space  30  also can communicate with the exterior. The third port  44  and the fourth port  46  are formed respectively on the lower casing  24  and the upper casing  22 , and are communicated through the second space  32 . Thereby the second space  32  also can communicate with the exterior. The air suction port  14  corresponds to the second port  42 . The air discharging port  16  corresponds to the third port  44 . A check valve (not shown in the drawings) may be interposed between the air suction port  14  and the second port  42 , and between the air discharging port  16  and the third port  44 . The trough  50  is formed by extending the outer surface of the lower casing  24  and communicates with the second space  32 . Namely the space formed by the trough  50  is a portion of the second space  32 . The cooling fins  52  are extended from the outer surface of the trough  50 . 
         [0016]    When the compressor starts operation, it sucks external air and compress the air to a selected location. The air enters through the first port  40  into the first space  30 . Meanwhile the check valve prevents the air from entering through the air discharging port  16  to the compression chamber  12 . Then the air flows through the second port  42  which communicates with the first space  30  and the air suction port  14  abutting the second port  42 , and enters the compression chamber  12  of the compressing unit  10  to be compressed. The compressed air is discharged through the air discharging port  16  outside the compression chamber  12 . The check valve also prevents the air from discharging through the air suction port  14  outside the compression chamber  12 . Next, the air passes through the third port  44  abutting the air discharging port  16  and enters the second space  32 , and passes through the fourth port  46  and flows out through the second space  32 . When the air is compressed, its temperature rises. The air flow contacts with the inner surface of the second space  32  to transfer heat to the exterior. The second space has a larger air housing capacity due to the trough  50 , and can increase the contact area with the air. The enlarged air housing space also can reduce pulse noise during the air compression, and also enable the compressed air to be discharged more smoothly. Increasing of the air contact area also can improve heat dissipation efficiency. The cooling fins  52  extended from the outer surface of the trough  50  can further enhance heat dissipation effect. 
         [0017]    Refer to  FIG. 3  for a second embodiment of the invention. It differs from the previous embodiment by having only one vent  62  on the washer  60 . The vent  62  corresponds to a distal end of the second space  32  on the lower casing  24 . The air flow path of this embodiment is as follow: first, the air enters the second space  32  of the lower casing  24  and flows to the distal end thereof; next enters the second space  32  of the upper casing  22  through the vent  62  of the washer  60  and flows to the distal end; finally the air is discharged through the fourth port  46 . Thus the air has a higher probability to be in contact with the surface of the second space  32  to absorb more heat. Therefore the air temperature discharged through the fourth port  46  is not too high. Compared with the first embodiment, it has a higher efficiency. 
         [0018]    In short, the invention provides a heat dissipation structure for a air compressor. During operation of the compressor the heat dissipation structure not only can increase heat dissipation efficiency, also provide a greater air housing capacity in a limited space of the compressor. Noise generated during operation of the compressor also can be reduced. It offers a significant improvement over the conventional techniques. 
         [0019]    While the preferred embodiments of the invention have been set forth for the purpose of disclosure, modifications of the disclosed embodiments of the invention as well as other embodiments thereof may occur to those skilled in the art. Accordingly, the appended claims are intended to cover all embodiments which do not depart from the spirit and scope of the invention.