1. Technical Field
The present disclosure relates to cooling systems, and more particularly to a cooling system for an automatic vending machine.
2. Description of Related Art
Automatic vending machines allow customers to buy product twenty four hours a day. The automatic vending machine often comprises a cooling device and a fan located in a bottom portion of the automatic vending machine. The cool air generated by the cooling device is transmitted to the interior of the automatic vending machine by the fan. The bottom portion of the automatic vending machine can be effectively cooled by the fan, but other portions, such as the top portion of the automatic vending machine, cannot be effectively cooled by the fan. Therefore, there is room for improvement within the art.
Many aspects of the embodiments 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 embodiments. Moreover, in the drawings, like-reference numerals designate corresponding parts throughout the several views.
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”.
The power supply module 10 comprises a first capacitor C1, a second capacitor C2, a power source 11, and a first sliding rheostat 12. The first sliding rheostat 12 comprises a first connecting end 13, a second connecting end 15, and a first sliding end 14 located between the first connecting end 13 and the second connecting end 15. A terminal of the power source 11 is connected to a power supply (not shown), and the power source 11 is grounded via the first capacitor C1 and the second capacitor C2. The first end 13 is connected to the output end of the power source 11, and the second end 15 is grounded. The first sliding end 14 is connected to the three detection modules 20. In one embodiment, the resistance of the first sliding rheostat 12 is 0˜1 KΩ, the capacitance of the first capacitor C1 is 1 Uf and substantially equal to the capacitance of the second capacitor C2, and the model of the power source 11 is 78L05A.
The second sliding rheostat 24 comprises a third connecting end 25, a fourth connecting end 27, and a second sliding end 26 located between the third connecting end 25 and the fourth connecting end 26. The third connecting end 25 is connected to the first node 28, and the fourth connecting end 27 and the second sliding end 26 are connected to the second node 29. A fourth resistor R4 is connected to the first node 28 and the second node 29. The negative terminal of the operational amplifier 22 is connected to the control module 30 and also connected to the output end of the operational amplifier 22 via a fifth resistor R5. The operational amplifier 22 is connected to the display 23. In one embodiment, the sensor 21 is a temperature sensor, the resistance of the first resistor R1 is 560 kΩ and substantially equal to the resistance of the second resistor R2. The resistance of the third resistor R3 is 100 kΩ the resistance of the fourth resistor R4 is 1 kΩ, and the resistance of the fifth resistor R5 is 1 MΩ.
In use, the power supply module 10 offers a stable voltage U0 to the three detection modules 20. The first sliding end 14 is slid to change the resistance of the first sliding rheostat 12. Then, the stable voltage U0 of the three detection modules 20 is changed to a voltage U1 via the sliding rheostat 12 and the first and third resistors R1, R3, and inputted to the negative terminal of the operational amplifier 22. In addition, the stable voltage U0 of the sensor 21 is changed to a voltage U2 according to the temperature to input to the positive terminal of the operational amplifier 22. The voltage U1, U2 are changed to a voltage U3 by the operational amplifier 22 and is displayed as a temperature value by the display 23. The voltage U3 of the three detection modules 20 are inputted into the control module 30. The voltage U3 of the first one of the three detection modules 20 is compared with the voltage U3 of the third one of the three detection modules 20 via the first comparator 31 to generate a voltage U4. Then, the control module 30 controls the first one of the two fans 40 according to the voltage U4 and a voltage range Uref. For example, if the voltage U4 is in the voltage range Uref, the control module 30 starts the first one of the two fans 40; and if the voltage U4 is out of the voltage range Uref, the control module 30 stops the first one of the two fans 40. Similarly, the voltage U3 of the second one of the three detection modules 20 is compared with the voltage U3 of the third one of the three detection modules 20 via the second comparator 31 to generate a voltage U5. Then, the control module 30 controls the second one of the two fans 40 according to the voltage U5 and a voltage range Uref. For example, if the voltage U5 is in the voltage range Uref, the control module 30 starts the second one of the two fans 40; and if the voltage U5 is out of the voltage range Uref, the control module 30 stops the second one of the two fans 40.
It is to be understood, however, that even though numerous characteristics and advantages have been set forth in the foregoing description of embodiments, together with details of the structures and functions of the embodiments, the disclosure is illustrative only and changes may be made in detail, especially in the 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.
Number | Date | Country | Kind |
---|---|---|---|
2013100761258 | Mar 2013 | CN | national |