Abstract:
A temperature control system ( 100 ) includes a heating system ( 1 ), a cooling system ( 2 ) and a control unit ( 3 ). The heating system has a heated fluid. The heated fluid is heated by a solar energy for increasing the mold temperature. The cooling system has a cooled fluid. The cooled fluid cools for decreasing the mold temperature. The control unit controls the heating system and the cooling system to be opened or closed.

Description:
TECHNICAL FIELD  
       [0001]     The present invention relates to a temperature control system and, more particularly, to a temperature control system for a mold.  
       BACKGROUND  
       [0002]     In the process of injection molding, hot molten thermoplastics are periodically injected into a cold mold. Without mold temperature control, the cavity surface will be heated unevenly due to the constant supply of heat from the molten plastic. Therefore, temperature control is a major prerequisite for achieving high molding quality.  
         [0003]     A typical temperature control system  99  for a mold is represented in  FIG. 5 . The temperature control system  99  is shown in use in a mold apparatus. The mold apparatus includes a housing  92  and a media cavity  93  defined therein. The temperature control system  99  includes a control panel  94 , a heat exchanger  95 , a heater  96 , a first electromagnetic valve  98  and a second electromagnetic valve  97 . The control panel  94  is located on the housing  92 . The mold body  102  also defines therein a media channel (not shown) communicating with the media cavity  93 . The media cavity  93  is filled with a media fluid, which flows in the channels for heating or cooling the housing  92  during molding. The heat exchanger  95  is disposed in the media cavity  93 , and the heater  96  is disposed on the outside of the media cavity  93  for heating the media fluid. The heat exchanger  95  is connected with the controlling panel  94  and the second electromagnetic valve  97  for controlling the mold cooling process. The heater  96  is connected with the controlling panel  94  and the first electromagnetic valve  98  for controlling the mold heating process. In use, the heater  96  heats the media cavity  93 . Then, the media cavity  93  further heats the media fluid. The media fluid transmits the energy to the mold cavity. When cooling, the heat exchanger  95  is filled with cooling water which carries energy from the media fluid so as to decrease the temperature of the mold. Users may control the first electromagnetic valve  98  and the second electromagnetic valve  97  by means of the controlling panel  94  thus enabling the user to control the heating and cooling processes of the mold. However, conventional temperature control systems use an electrical method of heating. This method consumes large amounts of electrical energy both in the heating and in the cooling processes of the mold.  
         [0004]     Therefore, a new temperature control system is desired in order to overcome the above-described problems.  
       SUMMARY OF THE INVENTION  
       [0005]     One embodiment of the temperature control system includes a heating system, a cooling system and a control unit. The heating system includes a heated fluid. The heated fluid is heated by solar energy for increasing the mold temperature. The cooling system has a cooled fluid. The cooled fluid can be used for decreasing the mold temperature. The control unit controls the activation of the heating system and the cooling system.  
         [0006]     Other advantages and novel features of the present temperature control system will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0007]     Many aspects of the temperature control system for a mold can be better understood with reference to the following drawings. The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the present invention. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views.  
         [0008]      FIG. 1  is a schematic view of an embodiment of the present temperature control system for a mold;  
         [0009]      FIG. 2  is a schematic view of the heating system of  FIG. 1 ;  
         [0010]      FIG. 3  is an isometric view of the collector of  FIG. 1 ;  
         [0011]      FIG. 4  is a schematic view of the cooling system of  FIG. 1 ; and  
         [0012]      FIG. 5  is a schematic view of a conventional temperature control system for a mold. 
     
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS  
       [0013]     Referring now to the drawings in detail,  FIG. 1  shows a temperature control system  100 , applied to an injecting mold. It is to be understood, however, that the temperature control system  100  could also be used in other environments (e.g. casting molds). As such, although proving particularly advantageous when used in injecting mold, the temperature control system  100  should not be considered limited in scope solely to an intended use environment. The injecting mold includes a mold body  102  with a media cavity  104  defined therein. The mold body  102  also defines therein a media channel (not shown) communicating with the media cavity  104 . The media cavity  104  is filled with a media fluid, which flows in the channels for heating or cooling the mold body  102  during molding.  
         [0014]     The temperature control system  100 , in the embodiment illustrated, includes a heating system  1 , a cooling system  2  and a control unit  3 . The heating system  1  includes a solar heating system  11  and an electrical system  30 .  
         [0015]     Referring also to  FIG. 2 , the solar heating system  11  includes a first electromagnetic valve  12 , a first pipe  14 , a first check valve  16  and a collector  18 . The above elements are connected with each other in that order by means of a fluid transmission channel, thereby forming a loop/circuit. The heating system  1  is filled with a heating fluid  10 , and the heating fluid  10  is circulated so as to heat the media fluid in the media cavity  104 , thereby heating the mold body.  
         [0016]     The electromagnetic valve  12  acts as a switch for the heating system  1 , being capable of either blocking or allowing through-put of the fluid  10 . The first pipe  14  is disposed in the media cavity  104 . The first pipe  14  is configured to have a spiral structure in order to provide a larger contact area with the media fluid in the media cavity  104 . This design may help energy conduction and allow the mold to be heated fully. The check valve  16  is a one-way valve element which can ensure that the hot fluid  10  of the heating system  1  flows only along a single direction.  
         [0017]     The collector  18  is an absorbing portion of the heating system  1 . The collector  18  is disposed at a position where the sun my directly irradiate it so that it may absorb solar energy. Referring also to  FIG. 3 , the collector  18  includes an absorbing panel  82 , a selective coating  84 , heat insulation layer  86  and a transparent cover  88 . The absorbing panel  82  includes a number of parallel tubes (not labeled). The fluid  10  may pass through the tubes from an input end of the collector  18  to an output end of the collector  18  so that the fluid  10  is heated by the absorbing panel  82 . The selective coating  84  is disposed on the absorbing panel  82 . The selective coating  84  is chosen to have properties which permit the collector  18  to absorb a large portion of the sun&#39;s wave radiation. An example of the type of selective coating  84  is black chrome or other dark color paints which provide high absorption and low emissivity. The heat insulation layer  86  encloses the absorbing panel  82  at two sides and a bottom thereof, thereby decreasing heat conduction to the surrounding environment. The transparent cover  88  covers the absorbing panel  82 . The transparent cover  88  not only separates the absorbing panel  82  from the air to decrease the energy loss owing to heat conduction or heat convection, but also avoids impurities or dust to drop onto the absorbing panel  82 .  
         [0018]     The flow of the heated fluid  10  of the solar heating system  11  may be driven to circulate under the thermo-syphon heat pipe principle. The electrical system  30  includes an electric heater  36  and a third electromagnetic valve  38 . The electric heater  36  is disposed outside of the mold cavity  104  for heating the mold and is electrically connected with the control panel  32 . The third electromagnetic valve  38  is for controlling the open and close of the electric heater  36 .  
         [0019]     Referring to  FIG. 4 , the cooling system  2  includes a second electromagnetic valve  22 , a second pipe  24 , a second check valve  26  and a heat exchanger  28 .  
         [0020]     The second electromagnetic valve  22  act as a switch for the cooling system  2 , being capable of either blocking or allowing through-put of the cooled fluid  20 . The second pipe  24  is also disposed in the media cavity  104 . The second pipe  24  is also configured to have a spiral structure in order to provide a larger contact area with the media fluid in the media cavity  104 . This design may help heat conduction and allow the media fluid to fully cool. The second check valve  26  is a one-way valve element which can ensure that the cooled fluid  20  of the cooling system  2  flows along one direction only. The heat exchanger  28  allows heat energy to be discharged as part of the cooling system  2 . The heat exchanger  28  can be a kind of a fin tube heat exchanger. The fin tube heat exchanger may effectively improve heat transfer to the surrounding environment.  
         [0021]     The control unit  3  includes a control panel  32  and a thermocouple  34 . The control panel  32  is connected with the first electromagnetic valve  12 , the second electromagnetic valve  22  and the third electromagnetic valve  38 . Users may send a control signal through the control panel  32  so as to control the opening and closing of the first electromagnetic valve  12 , the second electromagnetic valve  22  and the third electromagnetic valve  38 . The thermocouple  34  is electrically connected to the control panel  32 , thereby detecting the temperature of the mold. The detected result is shown on the control panel  32  so as to help users operate the mold.  
         [0022]     In use, the collector  18  firstly collects the solar energy and stores the solar energy for use. Then, the first electromagnetic valve  12  is opened by means of the control panel  32  when the mold needs to be heated. The heat absorbed by the collector  18  evaporates the fluid  10  and the evaporated fluid  10  is transmitted along the first pipe  14 . The first pipe  14  conducts the heat energy of the heated fluid  10  to the media cavity  104  of the mold. Accordingly, the temperature of the mold is increased. After the fluid  10  transmits the heat energy to the mold, the temperature of the fluid  10  is decreased and thus condensed back to liquid. The fluid  10  with a decreased temperature under thermo-syphon heat pipe principle again flows into the collector  18  so as to be heated. After a number of such circulations, the mold can be heated to a temperature of about 100˜120 C.°. The control panel  32  may detect the temperature of the heated mold. If the mold temperature does not satisfy the required temperature, the control panel  32  will automatically control the third electromagnetic valve  38  to activate the electric heater  36 , heating the mold cavity until a desired temperature is reached. Because of the subsidiary solar heating system  11 , the mold temperature control system  100  may greatly decrease the electrical energy consumption. When the mold needs to be cooled, the second electromagnetic valve  22  is opened by means of the control panel  32 . The cool fluid  20  heated by the media fluid in the media cavity  104 , flows to the heater exchanger  28  under the thermo-syphon heat pipe principle. The heat energy of the fluid  20  is transferred to the heater exchanger  28  and then dissipated to ambient air. After a number of circulations, the mold temperature will drop to the desired temperature.  
         [0023]     In the above-mentioned embodiments, the spiral structure of the first heat pipe act as a first condensing portion, and the collector thereof act as a first evaporating portion. The first condensing portion is received in the media cavity, and the first evaporating portion is located outside the media cavity. Understandably, the first condensing portion disclosed above may be replaced with other structures.  
         [0024]     In the above embodiment, the electrical heater is configured for heating the mold body to a predetermined temperature which the mold body cannot reach if heated by the first heat pipe alone.  
         [0025]     In the above embodiment, the temperature control system may adopt oils as heating transfer medium or cooling transfer medium. The use of a solar power is a more environmentally friendly source of power.  
         [0026]     It is believed that the present embodiments and their advantages will be understood from the foregoing description, and it will be apparent that various changes may be made thereto without departing from the spirit and scope of the invention or sacrificing all of its material advantages, the examples hereinbefore described merely being preferred or exemplary embodiments of the invention.