Heat exchanger

Abstract

In order to alleviate reduction in a heat exchange capability and to further improve the heat exchange capability, a heat exchanger of the present invention includes: a heat sink; and an electron emitting element which is provided so as to be separated from the heat sink by a space and which provides electrons to the heat sink via air in the space. The electron emitting element includes: an electrode substrate; a thin-film electrode; a power supply which applies a voltage between the electrode substrate and, the thin-film electrode; and an electron acceleration layer which accelerates electrons inside the electron acceleration layer in response to the voltage applied by the power supply so that the electrons are emitted from the thin-film electrode. The electron acceleration layer is made at least partially of an electric insulating material. The heat exchanger includes an air filter through which air flows onto a surface of the thin-film electrode. This can alleviate reduction in the heat exchange capability, caused by dust that adheres to a surface of the electron emitting element and therefore can attain an excellent heat exchange capability for long periods.

1 . A heat exchanger, comprising:
 an electron emitting element; and   an air filter,   the electron emitting element being provided so as to be separated, by a space, from a target of heat exchange having electrical conductivity and providing electrons to the target of heat exchange via air in the space, and   the heat exchanger exchanging heat between the target of heat exchange and the air,   the electron emitting element including:
 an electrode substrate; 
 a thin-film electrode; 
 first voltage applying means for applying a voltage between the electrode substrate and the thin-film electrode; and 
 an electron acceleration layer which accelerates electrons inside the electron acceleration layer in response to the voltage applied by the first voltage applying means so that the electrons thus accelerated are emitted from the thin-film electrode, 
   the electron acceleration layer being made at least partially of an electric insulating material, and   the air filter filtering air to flow onto a surface of the electron emitting element.   
     
     
         2 . The heat exchanger as set forth in  claim 1 , wherein:
 the air filter is a filter that collects and filters dust.   
     
     
         3 . The heat exchanger as set forth in  claim 1 , wherein:
 the air filter is a filter that collects and filters traces of gas in an atmosphere.   
     
     
         4 . The heat exchanger as set forth in  claim 3 , wherein:
 the air filter includes at least one of active carbon, manganese dioxide and titanium oxide.   
     
     
         5 . The heat exchanger as set forth in  claim 1 , wherein:
 the electric insulating material constituting the at least part of the electron acceleration layer includes particulate electric insulating particles.   
     
     
         6 . The heat exchanger as set forth in  claim 1 , wherein:
 the electric insulating material constituting the at least part of the electron acceleration layer includes either at least one of SiO 2 , Al 2 O 3 , and TiO 2 , or an organic polymer.   
     
     
         7 . The heat exchanger as set forth in  claim 1 , wherein:
 the thin-film electrode includes at least one of gold, carbon, nickel, titanium, tungsten and aluminum.   
     
     
         8 . The heat exchanger as set forth in  claim 5 , wherein:
 the electric insulating particles each have an average diameter which falls within a range from 10 nm to 1000 nm.   
     
     
         9 . The heat exchanger as set forth in  claim 1 , being a cooling device for cooling a heating element that serves as the target of heat exchange. 
     
     
         10 . The heat exchanger as set forth in  claim 1 , wherein:
 the target of heat exchange is a heat sink having an up-and-down surface which faces the electron emitting element.   
     
     
         11 . The heat exchanger as set forth in  claim 1 , wherein:
 the electron emitting element is configured to generate a gas flow in an atmosphere.   
     
     
         12 . The heat exchanger as set forth in  claim 1 , comprising:
 a fan which provides an airflow to a surface of the thin-film electrode.   
     
     
         13 . The heat exchange as set forth in  claim 1 , comprising:
 a rotary-blade airflow generator which includes blades provided so as to face the target of heat exchange and which rotates the blades so as to blow air toward the target of heat exchange,   wherein the electron emitting element is provided on a surface of at least one of the blades, the surface being opposite to the target of heat exchange.   
     
     
         14 . The heat exchanger as set forth in  claim 1 , wherein:
 the electron emitting element has a mash structure.   
     
     
         15 . The heat exchanger as set forth in  claim 1 , comprising:
 second voltage applying means for applying a voltage between the target of heat exchange and the electron emitting element,   wherein the voltage applied by the second voltage applying means is higher than 0 V but is not higher than +10 kV.   
     
     
         16 . The heat exchanger as set forth in  claim 15 , wherein:
 a strength of an electric field generated between the target of heat exchange and the electron emitting element falls within a range from 1 V/m to 10 7  V/m.   
     
     
         17 . The heat exchanger as set forth in  claim 1 , wherein:
 the target of heat exchange is grounded.   
     
     
         18 . The heat exchanger as set forth in  claim 1 , wherein:
 the target of heat exchange is separated from the electron emitting element by a distance which falls within a range from 100 μm to 50 cm.