Self-adjusting hot box

Abstract

A self-adjusting hot box includes a box ( 1 ) with a fan, a heater ( 50 ) placed in the box ( 1 ), a thermostat ( 30 ) and a power supply ( 20 ) applied to provide power to the fan ( 12 ), the thermostat ( 30 ) and the heater ( 50 ). The heater ( 50 ) includes a plurality of heat generating devices, and each of the heat generating devices includes a plurality of power resistors ( 60 ) in electrical parallel connection. The thermostat ( 30 ) includes a T type thermocouple ( 33 ) disposed in the box ( 1 ), a double-acting relay ( 37 ), a temperature controller ( 32 ) and a plurality of single-acting relays. The power supply ( 20 ) includes a transformer ( 21 ), a bridge clipper diode ( 23 ) and a capacitor ( 25 ).

1 . A self-adjusting hot box comprising: 
 a box having a supporting board disposed therein and a fan therein;    a heater placed in the box;    a thermostat electrically connected with the heater for controlling operation of the fan and the heater alternately; and    a power supply for providing power to the thermostat and the heater.    
   
   
       2 . The self-adjusting hot box as recited in  claim 1 , wherein the heater comprises a plurality of heat generating devices, and each heat generating device comprises a plurality of power resistors in electrical parallel connection.  
   
   
       3 . The self-adjusting hot box as recited in  claim 2 , wherein each of the heat generating devices of the heater further comprises a diode in electrical parallel connection with the power resistors.  
   
   
       4 . The self-adjusting hot box as recited in  claim 1 , wherein the power supply comprises: 
 a transformer;    a bridge clipper diode; and    a capacitor; wherein an input terminal of the transformer is input AC of 220V, an output terminal of the transformer is electrically connected with an input terminal of the bridge clipper diode, an output terminal of the bridge clipper diode is in electrical parallel connection with the capacitor, and a power output terminal of the power supply is connected with the capacitor and the bridge clipper diode.    
   
   
       5 . The self-adjusting hot box as recited in  claim 1 , wherein the thermostat comprises a temperature sensor disposed in the box, a double-acting relay and a temperature controller coupled with the temperature sensor and the double-acting relay.  
   
   
       6 . The self-adjusting hot box as recited in  claim 5 , wherein the temperature controller further comprises a pilot switch connected with the double-acting relay.  
   
   
       7 . The self-adjusting hot box as recited in  claim 5 , wherein the double-acting relay comprises a first key and a second key, the second key is switched on when the first key is cut off, the first key is switched on when the second key is cut off.  
   
   
       8 . The self-adjusting hot box as recited in  claim 7 , wherein a single-acting relay is connected with each heat generating device of the heater, the single-acting relay is connected with one terminal of the second key of the double-acting relay, and the other terminal of the second key is connected with the power output terminal of the power supply.  
   
   
       9 . The self-adjusting hot box as recited in  claim 1 , wherein the supporting board is net-shaped.  
   
   
       10 . The self-adjusting hot box as recited in  claim 1 , wherein a door with a handle is attached to the box, a middle portion of the door forms a transparent glass window.  
   
   
       11 . The self-adjusting hot box as recited in  claim 1 , wherein an opening is defined in the box, and the fan is received in the opening and connected with the thermostat.  
   
   
       12 . A self-adjusting hot box for testing hot property of an electrical component comprising: 
 a box having a supporting board disposed therein;    a heater placed in the box for heating the electrical component;    a thermostat electrically connecting the heater for controlling operation of the heater; and    a power supply for providing power to the thermostat and the heater.    
   
   
       13 . The self-adjusting hot box as recited in  claim 12 , wherein the heater comprises a plurality of heat generating devices, and each heat generating device comprises a plurality of power resistors and a diode in electrical parallel connection.  
   
   
       14 . The self-adjusting hot box as recited in  claim 12 , wherein the power supply comprises: 
 a transformer;    a bridge clipper diode; and    a capacitor; wherein an input terminal of the transformer is set to be AC of 220V, an output terminal of the transformer is electrically connected with an input terminal of the bridge clipper diode, an output terminal of the bridge clipper diode is in electrical parallel connection with the capacitor, and a power output terminal of the power supply is connected with the capacitor and the bridge clipper diode.    
   
   
       15 . The self-adjusting hot box as recited in  claim 12 , wherein the thermostat comprises a temperature sensor disposed in the box, a double-acting relay and a temperature controller coupled with the temperature sensor and the double-acting relay.  
   
   
       16 . The self-adjusting hot box as recited in  claim 15 , wherein the temperature controller further comprises a pilot switch connected with the double-acting relay.  
   
   
       17 . The self-adjusting hot box as recited in  claim 15 , wherein the double-acting relay comprises a first key and a second key, the second key is switched on when the first key is cut off, the first key is switched on when the second key is cut off.  
   
   
       18 . The self-adjusting hot box as recited in  claim 17 , wherein a single-acting relay is connected with each heat generating device of the heater, the single-acting relay is connected with one terminal of the second key of the double-acting relay, and the other terminal of the second key is connected with the power output terminal of the power supply.  
   
   
       19 . A method to establish a thermal test environment for an electrical device, comprising the steps of: 
 preparing a box with a temperature-controllable space therein;    equipping said box with a heater capable of raising temperature of said space;    ventilating said space of said box with an outside of said box; and    controlling said temperature of said space of said box by means of said heater and said ventilating step.    
   
   
       20 . The method as recited in  claim 19 , wherein a fan is equipped on said box to communicate said space with said outside of said box and perform said ventilating step.