1. Field of the Invention
The present invention relates to detection apparatuses, and particularly to an airflow detection apparatus.
2. Description of related art
Airflow detection apparatuses are essential in many applications. High power-density electronics are liable to overheat and damaged should a failure of cooling-fans occur unnoticed. Therefore, it becomes necessary to use some reliable means for airflow detection.
Usually, either a mechanical pressure-actuated vane switch or one of the various types of heat-transfer-based airflow sensors is employed. The mechanical pressure-actuated vane switches are inexpensive, but have low sensitivity. The heat-transfer-based airflow sensors have high sensitivity, but are expensive.
What is needed, therefore, is to provide an airflow detection apparatus which is inexpensive.
An exemplary airflow detection apparatus includes an enclosure defining a through hole therein, a conductive pole received in the through hole of the enclosure, and a first conductive board and a second conductive board respectively attached to a top end and a bottom plate of the enclosure. The second conductive board defines a through hole, and a size of the through hole of the second conductive board is greater than that of the pole. An end of the pole is directly connected to the first conductive board. An opposite end of the pole is passed through the through hole of the second conductive board, and then connected to a swing board. The first conductive board is electrically connected to an electrode of a power source, and the second conductive board is electrically connected to the other electrode of the power source, thereby an indicating circuit is formed. When the swing board is driven to swing by an airflow to contact with a side bounding the through hole of the second conductive board, the indicating circuit will work.
Other advantages and novel features will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings, in which:
Referring to
The enclosure 10 includes a cylinder-shaped main body 14, and a bottom plate 16 extending from a circumference of a bottom of the main body 14. The bottom plate 16 defines a depressed portion 160 in a bottom thereof, communicating with the through hole 12 of the enclosure 10. The depressed portion 160 defines a hole 162 neighboring the edge of the bottom plate 16. Two arc-shaped protrusions 122 symmetrically extend upwards from a top 120 of the main body 14. Two tabs 126 respectively perpendicularly extend out from distal ends of the protrusions 122. Between the protrusions 122, two openings 124 are formed.
The first conductive board 30 is circular. A projecting part 32 extends from a center of a bottom of the first conductive board 30. The first conductive board 30 defines a threaded hole 320 in a center thereof.
The second conductive board 40 is circular and defines a through hole 402 in a central portion thereof.
The connecting member 50 is generally n-shaped and includes two opposite arms portion 502, and a top plate 504 connecting tops of the arms portion 502. The top plate 504 defines a screw hole 509 therein. A hanging post 506 parallel to the top plate 504 connects lower parts of interior sides of the arms portion 502. A slot 508 is defined in a circumference of a middle of the hanging post 506.
The hook 60 has a generally inverted V shape.
The conductive pole 70 has a discoid-shaped cap 702 at a top thereof. The cap 702 defines a depressed portion 704. Two holes 706 are defined in a bottom of the depressed portion 704.
Referring also to
If there is no airflow, the swing board 80 will not swing and the conductive pole 70 will not contact an edge rounding the through hole 402 of the second conductive board 40, that is to say, the conductive pole 70 will not be electrically connected to the second conductive board 40. Thus, the indicator 94 will not light. When there is airflow, the swing board 80 is swung to drive the conductive pole 70 to electrically contact the second conductive board 40. Thus, the indicator 94 will light.
In this embodiment, the airflow detection apparatus can be adjusted to ensure a speed of the airflow. The adjusting screw 20 is screwed further into the threaded hole 320 of the first conductive board 30 to move the first conductive board 30 toward the connecting member 50. Thereby a distance between the first conductive board 30 and the cap 702 of the conductive pole 70 becomes less, and then the spring 90 is further distorted. At this time, only if a speed of the airflow is great enough, the swing board 80 can swing to drive the conductive pole 70 to contact the edge of the through hole 402 of the second conductive board 40.
In other embodiments, the conductive pole 70 can be a pole and the cap 702 omitted. The swing board 80 then extends from one end of the conductive pole 70, and the opposite end of the conductive pole 70 is directly fixed to the first conductive board 30.
It is believed that the present embodiments and theirs 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.
Number | Date | Country | Kind |
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200810300050.6 | Jan 2008 | CN | national |