Abstract:
An environmental testing device includes a humidity control module, a temperature control module; and an air circulation module. The air circulation module includes an enclosure and a fan received in the enclosure. Two pairs of airflow openings are defined in the enclosure and form different airflow passages that allow air to flow along different directions in the environmental testing device.

Description:
BACKGROUND 
     1. Technical Field 
     The present disclosure relates to an environmental testing device capable of performing environmental testing on electronic devices. 
     2. Description of Related Art 
     Many types of electronic devices undergo a series of environmental tests under various combinations of temperature, humidity, and other climatic conditions produced using environmental testing devices to insure product reliability and performance at extreme environmental conditions. 
     Referring to  FIG. 4 , a typical environmental testing device  100  has an air circulation module  102  mounted therein. A fan (not shown) is disposed in the air circulation module  102 . The air circulation module  102  has an air inlet  104  and an air outlet  106 . When the environmental testing device  100  performs environmental tests on electronic devices placed therein, the fan outputs air from the air outlet  106  and draws air into the air inlet  104  to accelerate airflow in the device  100 . However, the fan in the air circulation module  102  outputs air along a single direction, and air temperatures may not be uniform throughout the device  100 . That may decrease accuracy of the test results. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a block diagram of an environmental testing device according to an embodiment. 
         FIG. 2  is an exploded view of an air circulation module according to an embodiment. 
         FIG. 3  is an assembled view of  FIG. 2 . 
         FIG. 4  illustrates a typical environmental testing device according to the prior art. 
     
    
    
     DETAILED DESCRIPTION 
     The disclosure is illustrated by way of example and not by way of limitation in the figures of the accompanying drawings in which like references indicate similar elements. It should be noted that references to “an” or “one” embodiment in this disclosure are not necessarily to the same embodiment, and such references mean at least one. 
     Referring to  FIG. 1 , an embodiment of an environmental testing device  10  includes a humidity sensor  20 , a humidity control module  30  connected to the humidity sensor  20 , a temperature sensor  40 , a temperature control module  50  connected to the temperature sensor  40 , and an air circulation module  60 . The humidity control module  30  includes a humidity increasing module  32  and a humidity decreasing module  34 . The temperature control module  50  includes a heating module  52  and a cooling module  54 . The air circulation module  60  has a first airflow outlet  821   a , a first airflow inlet  821   b , a second airflow outlet  823   a , and a second airflow inlet  823   b.    
     Referring to  FIGS. 2 and 3 , the air circulation module  60  includes a holding portion  80 , a cover portion  90 , and a fan  70  adapted to be accommodated in the holding portion  80 . The holding portion  80  includes a hollow cylindrical main body  82 . A base of the main body  82  is closed, and a top of the main body  82  is open. 
     The first airflow outlet  821   a , the second airflow outlet  823   a , the first airflow inlet  821   b , and the second airflow inlet  823   b  are evenly defined in the side face of the main body  82 . A circular airflow guide  825  protrudes an edge of each of the first airflow outlet  821   a , the second airflow outlet  823   a , the first airflow inlet  821   b , and the second airflow inlet  823   b.    
     The first air outlet  821   a  and the first air inlet  821   b  form a first airflow passage that allows air to flow along a first direction. The second air outlet  823   a  and the second air inlet  823   b  form a second airflow passage that allows air to flow along a second direction. The first direction is perpendicular to the second direction. An axis of the holding portion  80  is perpendicular to each of the first direction and the second direction. The cover portion  90  includes a circular panel  92 , a pair of arc-shaped side plates  94  extending down from the circular panel  92 , and a mounting bracket  96  mounted between the side plates  94 . A handle  921  is formed on the circular panel  92  of the cover portion  90 . 
     In assembly of the air circulation module  60 , the fan  70  is mounted in the mounting bracket  96  of the cover portion  90 . The arc-shaped side plates  94  of the cover portion  90  are inserted in the holding portion  80  and abut an inner surface of the holding portion  80 . The fan  70  mounted in the mounting bracket  96  of the cover portion  90  is received in the holding portion  80 . Then the handle  921  of the cover portion  90  is rotated to adjust direction of the fan  70 . In one embodiment, a front side of the fan  70  is located at the same side as the first air outlet  821   a  and the second air outlet  823   a  to output air through the first and second air outlets  821   a ,  823   a . A rear side of the fan  70  is located at the same side as the first air inlet  821   b  and the second air inlet  823   b  for drawing in air from the first and second air inlet  821   b ,  823   b.    
     To perform environmental testing on electronic devices (e.g. computer motherboards), the electronic devices are placed in the environmental testing device  10 . The environmental testing device  10  is started. The humidity sensor  20  senses humidity in the environmental testing device  10  and informs the humidity control module  30 . The humidity control module  30  compares the humidity with a predetermined humidity value. If the humidity in the environment testing device  10  exceeds the predetermined humidity value, the humidity decreasing module  34  is started to decrease the humidity in the environmental testing device  10 . If the humidity in the environmental testing device  10  is less than the predetermined humidity value, the humidity increasing module  32  is started to increase the humidity in the environmental testing device  10 . Thus, the environmental testing device  10  can produce the predetermined humidity condition. 
     The temperature sensor  40  senses the temperature in the environmental testing device  10  and informs the temperature control module  50 . The temperature control module  50  compares the temperature with a predetermined temperature. If the temperature in the environmental testing device  10  exceeds the predetermined temperature, the cooling module  54  is started to decrease the temperature in the environmental testing device  10 . If the temperature in the environmental testing device  10  is less than the predetermined temperature, the heating module  52  is started to increase the temperature in the environmental testing device  10 . Thus, the environment testing device  10  can produce the predetermined temperature condition. 
     The fan  70  in the air circulation module  60  is started. The fan  70  draws in air from the first air inlets  821   b  and outputs air through the first air outlets  821   a  along the first airflow passage. The fan  70  also draws in air from the second air inlets  823   b  and outputs air through the second air outlets  823   a  along the second airflow passage. In one embodiment, air in the environmental testing device  10  flows along different directions. Air temperatures in the environmental testing device  10  are more even, which can increase accuracy of the test result. 
     It is to be understood, however, that even though numerous characteristics and advantages of the embodiments have been set forth in the foregoing description, together with details of the structure and function of the embodiments, the disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size, and arrangement of parts within the principles of the disclosure to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.