US 12,235,147 B2
Apparatus and method for sensing water level
Young-Hwan Choi, Seoul (KR); and Sung-An Ha, Gyeongsangbuk-do (KR)
Assigned to NANOKEM CO., LTD., Gyeongsangbuk-do (KR)
Appl. No. 17/796,081
Filed by NANOKEM CO., LTD., Gyeongsangbuk-do (KR)
PCT Filed Jan. 26, 2021, PCT No. PCT/KR2021/001020
§ 371(c)(1), (2) Date Jul. 28, 2022,
PCT Pub. No. WO2021/153970, PCT Pub. Date Aug. 5, 2021.
Claims priority of application No. 10-2020-0010791 (KR), filed on Jan. 30, 2020.
Prior Publication US 2023/0113463 A1, Apr. 13, 2023
Int. Cl. G01F 23/24 (2006.01)
CPC G01F 23/244 (2013.01) [G01F 23/241 (2013.01)] 6 Claims
OG exemplary drawing
 
1. A water level detection apparatus comprising:
a micom outputting a first low water level control signal and a second low water level control signal which are square waves having a frequency, and have opposite phases, and receiving water level detection signals for the first low water level control signal and the second low water level control signal, and performing a response operation;
a control signal output unit receiving the first low water level control signal and the second low water level control signal, and outputs plus DC power and minus DC power having opposite phases for each of the first low water level control signal and the second low water level control signal;
a conversion unit being applied with the plus DC power and the minus DC power, and outputting a water level monitoring signal which is AC power;
a water level detection unit supplying the water level monitoring signal to a water level sensor, and outputting a water level detection signal when detecting a low water level of a predetermined reference or less; and
a water level signal input unit receiving the water level detection signal and outputting the water level detection signal to the micom,
wherein the control signal output unit includes:
a first switching unit in which an output terminal is connected to a primary plus terminal of the conversion unit, and which receives the first low water level control signal to be turned on or off,
a second switching unit in which the output terminal is connected to a primary minus terminal of the conversion unit, and which receives the second low water level control signal to be turned on or off, and is turned on when the first switching unit is turned off, and
a phase alternate DC voltage supply unit in which one side is connected to the output terminal of the first switching unit and another side is connected to the output terminal of the second switching unit, and in order to alternately supply the plus DC power and the minus DC power to the primary side of the conversion unit, the DC voltage is connected between the one side and the other side, and then connected to a primary intermediate point of the transformer to alternately supply DC powers having different phases by turning on the first switching unit and the second switching unit to the primary intermediate point of the transformer;
wherein the phase alternate DC voltage supply unit includes:
a first diode in which an anode is connected to the output terminal of the first switching unit and a cathode is connected to the intermediate point,
a second diode in which the anode is connected to the output terminal of the second switching unit and the cathode is connected to the intermediate point, and
a third resistor in which the DC power is applied to one terminal and the other terminal is connected to the cathodes of the first diode and the second diode.