Water meter with electronic meter reading device

Abstract

The present invention relates to a water meter that applies an electronic metering device in which a light-emitting sensor and two light-receiving sensors are arranged facing each other around a cylindrical sensing block, the signals of the two light-receiving sensors output by the light-emitting sensor are combined by a logic circuit, the output signal of the logic circuit is input to an MCU, and the MCU counts the output signal of the logic circuit to calculate the amount of tap water used. A water meter with an electronic metering device according to the present invention comprises a lower outer casing (10) having an inlet (11) and an outlet (12) formed therein, a lower inner casing (20) disposed on a seat portion (13) of the lower outer casing (10), an impeller (30) mounted on the lower inner casing (20) and rotated by the flow of water, an upper inner casing (40) seated on the lower inner casing (20), a gear box (50) disposed inside the upper inner casing (40), a gear set (60) disposed inside the gear box (50) and coupled with the rotation axis (35) of the impeller (30), a counter wheel unit (70) coupled with the gear set (60) to display the flow rate used, and an upper outer casing (80) coupled to the lower outer casing (10) to cover the gear box (50), wherein a cylindrical shape on the rotation axis (62c) of one of the gears of the gear set (60) The device further comprises an electronic meter reading device (100) in which a sensing block (110) is mounted so that the sensing block (110) rotates by a rotation axis (62c), a light-emitting sensor (120) and two light-receiving sensors (130, 135) are arranged facing each other around the center of the cylindrical sensing block (110), the signals of the two light-receiving sensors (130, 135) output by the light-emitting sensor (120) are combined by a logic circuit unit (140), the signals of the logic circuit unit (140) are input to an MCU (150), and the MCU (150) counts the signals of the logic circuit unit (140) to calculate the amount of tap water used.

Description

Technology Field

[0001] The present invention relates to a water meter with an electronic metering device, and more specifically, to a water meter with an electronic metering device in which a light-emitting sensor and two light-receiving sensors are arranged facing each other around a cylindrical sensing block, the signals of the two light-receiving sensors output by the light-emitting sensor are combined by a logic circuit, the output signal of the logic circuit is input to an MCU, and the MCU counts the output signal of the logic circuit to calculate the amount of tap water used. Background Technology

[0003] Korean Patent No. 10-1303115 (registered on August 28, 2013) describes an "electronic meter reading device using a mechanical water meter."

[0004] An electronic meter reading device using the above-described mechanical water meter comprises: a water meter body having a fluid inlet and a fluid outlet formed therein; an impeller installed inside the water meter body; and an accumulation display unit that accumulates the flow rate of the fluid by the rotation of instrument gears according to the rotation of the impeller. The device further comprises: a plurality of sensors that output an on / off detection signal by the rotation of the reflector, wherein the gears of the accumulation display unit are equipped with a star-shaped pinwheel indicating that water is passing through, and one or more rotary scale plates that rotate in conjunction with intermediate gears to indicate different flow rates, and a reflector plate is provided on the upper part of any one of the rotary scale plates; and a control unit that counts the detection signals output from the sensors to accumulate and display the amount of water used; an inner cover that seals and covers the accumulation display unit and is coupled to the water meter body; an outer cover coupled to the water meter body on the upper surface of the inner cover to surround the inner cover; and a coupling member that combines the inner cover and the outer cover with the water meter body.

[0005] However, the electronic meter reading device using the above mechanical water meter electronically measures the water meter usage by detecting signals from the first transmitting sensor and the second receiving sensor according to the rotation of the reflector plate, but has a disadvantage in that if chatter occurs on the reflector plate, the ON signal of the second receiving sensor increases, which may cause calculation errors due to measurement errors. The problem to be solved

[0007] Accordingly, the objective of the present invention is to provide a water meter equipped with an electronic metering device, wherein a light-emitting sensor and two light-receiving sensors are arranged facing each other around a cylindrical sensing block mounted on the rotation axis of one gear of a gear set, the signals of the two light-receiving sensors output by the light-emitting sensor are combined by a logic circuit, the output signal of the logic circuit is input to an MCU, and the output signal of the logic circuit is counted by the MCU to calculate the water usage amount, thereby enabling stable and accurate metering even if chatter occurs in the sensing block, displaying the sum of the water usage amount measured using the electronic metering device and the existing accumulated amount on an indicator, and automatically transmitting the water usage amount to the water utility company's server on a fixed date each month. means of solving the problem

[0009] An example of a water meter equipped with an electronic meter reading device according to the present invention for achieving the above-mentioned purpose is,

[0010] A water meter comprising: a lower outer casing having an inlet and an outlet formed therein; a lower inner casing disposed on the seat portion of the lower outer casing; an impeller mounted on the lower inner casing and rotating by the flow of water; an upper inner casing seated on the lower inner casing; a gearbox disposed inside the upper inner casing; a gear set disposed inside the gearbox and coupled to the rotation axis of the impeller; a counter wheel unit coupled to the gear set to display the flow rate used; and an upper outer casing coupled to the lower outer casing to cover the gearbox.

[0011] The device further comprises an electronic meter reading device in which a cylindrical sensing block is mounted on the rotation axis of one gear of a gear set, so that the sensing block rotates by the rotation axis, a light-emitting sensor and two light-receiving sensors are arranged facing each other with the center of the cylindrical sensing block, the signals of the two light-receiving sensors output by the light-emitting sensor are combined by a logic circuit, the signals of the logic circuit are input to an MCU, and the MCU counts the signals of the logic circuit to calculate the amount of tap water used.

[0012] The above sensing block is mounted on the upper end of the rotation shaft of the second gear constituting the gear set and rotates by the rotation shaft, and a cutting portion is positioned between two arc blocking portions, so that when the arc blocking portion is positioned between the light emitting sensor and the light receiving sensor, the light signal provided from the light emitting sensor to the light receiving sensor is blocked by the arc blocking portion, and when the cutting portion is positioned between the light emitting sensor and the light receiving sensor, the light signal of the light emitting sensor is input to the light receiving sensor through the cutting portion.

[0013] The light receiving sensor is positioned facing the light emitting sensor, and two light receiving sensors are spaced apart from each other by a predetermined angle (a) with respect to the light emitting sensor, and the two light receiving sensors are positioned within the width range of the cut section.

[0014] By this, when the light signal of the light-emitting sensor is input to both the first and second light-receiving sensors through the cut-out portion of the sensing block, the ON signals of the first and second light-receiving sensors are input to the logic circuit portion, respectively, and the logic circuit portion outputs a RO signal to the MCU.

[0015] When the sensing block rotates, and the light signal of the light-emitting sensor is not input to the first light-receiving sensor by the arc blocking part of the sensing block but is input to the second light-receiving sensor through the cut-out part of the sensing block, the off signal of the first light-receiving sensor and the on signal of the second light-receiving sensor are respectively input to the logic circuit part, and the logic circuit part maintains the previous low signal as is.

[0016] When the sensing block rotates further, and the light signal of the light-emitting sensor is not input to the first light-receiving sensor and the second light-receiving sensor by the arc blocking part of the sensing block, the off signals of the first light-receiving sensor and the second light-receiving sensor are input to the logic circuit part, and the logic circuit part outputs a high signal.

[0017] When the sensing block rotates further, the light signal of the light-emitting sensor is not input to the second light-receiving sensor by the arc blocking part of the sensing block, but is input to the first light-receiving sensor through the cut-out part of the sensing block, the ON signal of the first light-receiving sensor and the OFF signal of the second light-receiving sensor are respectively input to the logic circuit part, and the logic circuit part maintains the previous high signal as is.

[0018] When a signal is input to the MCU from the above logic circuit, the MCU counts low and high signals at regular intervals to calculate the water usage, displays the calculated water usage plus the existing accumulated amount on an indicator, and transmits the water usage to the water utility company's server on a fixed date each month.

[0019] The above gear set is characterized by the lower gear of the first gear being linked to the driving gear coupled to the rotation axis of the impeller, a star needle being mounted on the upper end of the rotation axis of the first gear, the lower gear of the second gear being linked to the upper gear of the first gear, a sensing block being mounted on the upper end of the rotation axis of the second gear, the lower gear of the third gear being linked to the upper gear of the second gear, a 0.1L indicator being mounted on the upper end of the rotation axis of the third gear, the third gear being linked to the fourth gear through a reduction gear, a 1L indicator being mounted on the upper end of the rotation axis of the fourth gear, the fourth gear being linked to the fifth gear through a reduction gear, a 10L indicator being mounted on the upper end of the rotation axis of the fifth gear, the fifth gear being linked to the sixth gear through a reduction gear, a 100L indicator being mounted on the upper end of the rotation axis of the sixth gear, and the sixth gear being linked to the worm gear of the counter wheel unit through a power transmission gear.

[0020] The above gear box is characterized by having a hole drilled in the upper transparent plate, a sensing block protruding rotatably through the hole, and a transparent protective cover plate being in close contact with the upper transparent plate so that the sensing block is inserted into the interior of the block housing portion formed in the protective cover plate.

[0021] The light-emitting sensor and the light-receiving sensor are respectively placed inside the first sensor housing portion and the second sensor housing portion of a transparent inspection case, the inspection case is covered by an opaque cover, the coupling groove of the coupling portion formed on the side of the inspection case is coupled to the coupling projection of the coupling ring, the coupling ring is mounted on the upper outer shell, and the first sensor housing portion and the second sensor housing portion of the inspection case are in close contact with a protective cover plate, thereby a block housing portion including a sensing block is disposed between the first sensor housing portion including the light-emitting sensor and the second sensor housing portion including the light-receiving sensor.

[0022] The above-mentioned meter reading case is characterized by having a PCB containing an MCU and a logic circuit and a battery for power supply built in, a light-emitting sensor and a light-receiving sensor mounted on the PCB, an indicator for displaying water usage, and an NFC antenna for transmitting water usage data to a water utility operator's management server.

[0023] The above-described meter reading case is characterized by having an L-shaped neck portion formed on one side of a square portion, and a first sensor housing portion and a second sensor housing portion formed to protrude downward from the neck portion. Effects of the invention

[0025] As a result, a water meter equipped with an electronic meter reading device according to the present invention can stably and accurately measure water usage even if chatter occurs in the sensing block, and displays the sum of the water usage measured using the electronic meter reading device and the existing accumulated amount on an indicator, and has the effect of automatically transmitting the water usage to the water utility's server on a fixed date every month. Brief explanation of the drawing

[0027] Figure 1 is a cross-sectional view illustrating a typical water meter. FIG. 2 is a cross-sectional view illustrating a water meter to which an electronic meter reading device according to the present invention is applied. Figure 3 is a schematic plan view illustrating the arrangement of an electronic meter reading device on a manual meter. Figure 4 schematically illustrates the circuit of an electronic meter reading device. FIG. 5 illustrates examples in which the light signal of a light-emitting sensor is input to two light-receiving sensors through a sensing block, wherein (a) the light signal of the light-emitting sensor is input to two light-receiving sensors, (b) and (d) the light signal of the light-emitting sensor is input to one light-receiving sensor by the sensing block, and (c) the light signal of the light-emitting sensor is not input to a light-receiving sensor by the sensing block. FIG. 6 is a plan view illustrating a gearbox including a gear set and a counterwheel unit. FIG. 7 is an exploded perspective view illustrating a water meter to which an electronic meter reading device according to the present invention is applied. FIG. 8 is an exploded perspective view illustrating an example in which a meter reading case is mounted on a water meter. FIG. 9 is an assembled perspective view of a water meter with a meter reading case attached. FIG. 10 is a perspective view illustrating a meter reading case. Specific details for implementing the invention

[0028] Hereinafter, embodiments according to the present invention will be described in detail with reference to the accompanying drawings. This description is not intended to limit the present invention to specific embodiments and should be understood to include all modifications, equivalents, and substitutions that fall within the spirit and scope of the present invention. Unless otherwise defined, all terms used in this specification, including technical or scientific terms, have the same meaning as generally understood by a person skilled in the art to which the present invention pertains.

[0029] In this document, when a part is described as "including" a certain component, it means that, unless specifically stated otherwise, it does not exclude other components but may include additional components.

[0031] Referring to FIG. 1, generally, a water meter comprises a lower outer casing (10) having an inlet (11) and an outlet (12) formed therein, a lower inner casing (20) positioned on the seat portion (13) of the lower outer casing (10), an impeller (30) mounted on the lower inner casing (20) and rotated by the flow of water, an upper inner casing (40) seated on the lower inner casing (20), a gear box (50) positioned inside the upper inner casing (40), a gear set (60) positioned inside the gear box (50) and coupled with the rotation axis (35) of the impeller (30), a counter wheel unit (70) coupled with the gear set (60) to display the flow rate used, and an upper outer casing (80) coupled to the lower outer casing (10) to cover the gear box (50).

[0032] Referring to FIGS. 2 to 5, the water meter to which the electronic meter reading device according to the present invention is applied further comprises an electronic meter reading device (100) in which a cylindrical sensing block (110) is mounted on a rotation shaft (62c) of one gear of a gear set (60), so that the sensing block (110) rotates by the rotation shaft (62c), and a light-emitting sensor (120) and two light-receiving sensors (130, 135) are arranged facing each other around the cylindrical sensing block (110), and the signals of the two light-receiving sensors (130, 135) output by the light-emitting sensor (120) are combined by a logic circuit unit (140), the signals of the logic circuit unit (140) are input to an MCU (150), and the MCU (150) counts the signals of the logic circuit unit (140) to calculate the amount of tap water used.

[0033] The above sensing block (110) is mounted on the upper end of the rotation axis (62c) of the second gear (62) constituting the gear set (60) and rotates by the rotation axis (62c). A cutting section (112) is positioned between two arc blocking sections (111, 113). When the arc blocking sections (111, 113) are positioned between the light-emitting sensor (120) and the light-receiving sensor (130, 135), the light signal provided from the light-emitting sensor (120) to the light-receiving sensor (130, 135) is blocked by the arc blocking sections (111, 113). When the cutting section (112) is positioned between the light-emitting sensor (120) and the light-receiving sensor (130, 135), the light signal of the light-emitting sensor (120) is input to the light-receiving sensor (130, 135) through the cutting section (112).

[0034] The light receiving sensors (130, 135) are positioned facing the light emitting sensor (120), and the two light receiving sensors (130, 135) are spaced apart from each other by a predetermined angle (a; for example, 35°) with respect to the light emitting sensor (120), and the two light receiving sensors (130, 135) are positioned within the width range of the cut section (112).

[0035] By this, when voltage is applied to the base of the transistor (TR) from the MCU (150) in a water meter according to the present invention as shown in FIG. 4, the light-emitting sensor (120) and the transistor (TR) are turned on, causing light to be projected from the light-emitting sensor (120), and the light signal of the light-emitting sensor (120) is received by the first and second light-receiving sensors (130, 135).

[0036] At this time, as illustrated in FIG. 5 (a), when the light signal of the light-emitting sensor (120) is input to both the first and second light-receiving sensors (130, 135) through the cut-out portion (112) of the sensing block (110), the ON signals of the first and second light-receiving sensors (130, 135) are input to the logic circuit portion (140), respectively, and the logic circuit portion (140) outputs a RO signal to the MCU (150).

[0037] And, when the sensing block (110) rotates counterclockwise as shown in the arrow, and as illustrated in FIG. 5 (b), the light signal of the light-emitting sensor (120) is not input to the first light-receiving sensor (130) by the arc blocking part (111) of the sensing block (110) but is input to the second light-receiving sensor (135) through the cut-out part (112) of the sensing block (110), the off signal of the first light-receiving sensor (130) and the on signal of the second light-receiving sensor (135) are respectively input to the logic circuit part (140), and the logic circuit part (140) maintains the previous low signal.

[0038] Afterwards, the sensing block (110) rotates counterclockwise as shown in the arrow, and as illustrated in Fig. 5 (c), if the light signal of the light-emitting sensor (120) is not input to the first light-receiving sensor (130) and the second light-receiving sensor (135) by the arc blocking part (111, 113) of the sensing block (110), the off signal of the first light-receiving sensor (130) and the second light-receiving sensor (135) is input to the logic circuit part (140), and the logic circuit part (140) outputs a high signal.

[0039] Afterwards, the sensing block (110) rotates counterclockwise as shown by the arrow, and as illustrated in Fig. 5 (d), the light signal of the light-emitting sensor (120) is not input to the second light-receiving sensor (135) by the arc blocking part (111) of the sensing block (110), but is input to the first light-receiving sensor (130) through the cut-out part (112) of the sensing block (110). Then, the ON signal of the first light-receiving sensor (130) and the OFF signal of the second light-receiving sensor (135) are each input to the logic circuit part (140), and the logic circuit part (140) maintains the previous high signal.

[0040] And, when a signal is input from the logic circuit (140) to the MCU (150) as described above, the MCU (150) counts low and high signals at regular intervals to calculate the water usage, and displays the calculated water usage plus the existing accumulated amount on the indicator. Then, on a set date each month, the water usage is transmitted to the water utility company's server (170).

[0041] In this way, the water meter with the electronic meter reading device according to the present invention enables accurate metering because, even if the sensing block (110) experiences chattering that causes it to reciprocate between the positions of (a) and (b) or (c) and (d) in Fig. 5 due to vibration or fluid shock, both light receiving sensors (130, 135) must output an ON signal or an OFF signal so that the low signal or high signal output from the logic circuit (140) to the MCU (150) is changed.

[0042] In addition, the value obtained by adding the water usage measured using an electronic metering device and the existing accumulated amount can be displayed on an indicator, and the water usage can be automatically transmitted to the water utility company's server (170) on a set date each month.

[0044] We will now describe the configuration for implementing a water meter to which the electronic meter reading device according to the present invention as described above is applied.

[0045] Referring to FIGS. 3 and 6, the gear set (60) is coupled to a drive gear (37) connected to the rotation axis (35) of an impeller (30; see FIG. 1), the lower gear (61a) of the first gear (61) is coupled to the rotation axis (61c) of the first gear (61), a star needle (61d) is mounted on the upper end of the rotation axis (61c) of the first gear (61), the lower gear (62b) of the second gear (62) is coupled to the upper gear (61b) of the first gear (61), a sensing block (110) is mounted on the upper end of the rotation axis (62c) of the second gear (62), the lower gear of the third gear (63) is coupled to the upper gear (62c) of the second gear (62), a 0.1L needle (63d) is mounted on the upper end of the rotation axis (63c) of the third gear (63), and the third gear (63) is coupled to the fourth through a reduction gear The gear (64) is linked to the 4th gear (64), a 1L indicator (64d) is mounted on the upper end of the rotation axis (64c) of the 4th gear (64), the 4th gear (64) is linked to the 5th gear (65) through a reduction gear, a 10L indicator (65d) is mounted on the upper end of the rotation axis (65c) of the 5th gear (65), the 5th gear (65) is linked to the 6th gear (66) through a reduction gear, a 100L indicator (66d) is mounted on the upper end of the rotation axis (66c) of the 6th gear (66), and the 6th gear (66) is linked to the worm gear (71) of the counter wheel unit (70) through an electric gear.

[0046] Referring to FIGS. 2 and FIGS. 7, the gear box (50) has a hole (52) drilled in the upper transparent plate (51), and a sensing block (110) protrudes rotatably through the hole (52), and a transparent protective cover plate (180) is attached to the upper transparent plate (51), so that the sensing block (110) is inserted into the interior of the block housing part (181) formed in the protective cover plate (180).

[0047] By this, the upper transparent plate (51) of the gear box (50) is sealed by the protective cover plate (180), and the sensing block (110) is protected by the block housing part (181) of the protective cover plate (180).

[0048] Referring to FIGS. 7, 8, and 9, the light-emitting sensor (120) and the light-receiving sensor (130, 135) are respectively placed inside the first sensor housing portion (211) and the second sensor housing portion (212) of a transparent inspection case (200), the inspection case (200) is covered by an opaque cover (220), and a coupling groove (not shown) of a coupling portion (215, 216) formed on the side of the inspection case (200) is coupled to a coupling projection (91, 92) of a coupling ring (90), the coupling ring (90) is mounted on an upper outer shell (80), and the first sensor housing portion (211) and the second sensor housing portion (212) of the inspection case (200) are in close contact with a protective cover plate (180), thereby the first sensor housing portion (211) including the light-emitting sensor (120) and A block housing part (181) including a sensing block (110) is disposed between a second sensor housing part (212) including a light receiving sensor (130, 135).

[0049] Referring to FIG. 10, the meter reading case (200) has a PCB (220) containing an MCU (150; see FIG. 4) and a logic circuit (140; see FIG. 4) and a power supply battery (230) built into it, a light-emitting sensor (120) and a light-receiving sensor (130, 135) are mounted on the PCB (220), and an indicator (240) that displays the water usage amount and an NFC antenna (170) are mounted to transmit the water usage data to the water utility operator's management server (170; see FIG. 4).

[0050] In addition, the above-mentioned metering case (200) has a neck portion (205) in the shape of an L-shape formed on one side of the square portion (203), and a first sensor housing portion (211) and a second sensor housing portion (212) are formed to protrude downward from the neck portion (205).

[0052] As described above, the present invention has been explained by specific details such as specific components and limited embodiments; however, this is provided merely to aid in a more comprehensive understanding of the invention, and the invention is not limited to the above embodiments. A person skilled in the art to which the invention pertains can make various modifications and variations from this description.

[0053] Accordingly, the scope of the present invention is not limited to the described embodiments, and all things equivalent to or having equivalent variations to the claims set forth below, as well as the claims set forth below, shall be considered to fall within the scope of the concept of the present invention. Explanation of the symbols

[0055] 10: Lower outer shell 20: Lower inner shell 30 : Impeller 40 : Upper inner casing 50: Gearbox 60: Gear set 70: Count wheel unit 110: Sensing block 130, 135: Light receiving sensors 140: Logic circuit section 150 : MCU

Claims

Claim 1 A water meter comprising a lower outer casing (10) having an inlet (11) and an outlet (12) formed therein, a lower inner casing (20) disposed on a seat portion (13) of the lower outer casing (10), an impeller (30) mounted on the lower inner casing (20) and rotated by the flow of water, an upper inner casing (40) seated on the lower inner casing (20), a gear box (50) disposed inside the upper inner casing (40), a gear set (60) disposed inside the gear box (50) and coupled with the rotation axis (35) of the impeller (30), a counter wheel unit (70) coupled with the gear set (60) to display the flow rate used, and an upper outer casing (80) coupled to the lower outer casing (10) to cover the gear box (50), wherein a cylindrical sensing block (110) is mounted on the rotation axis (62c) of one of the gears of the gear set (60). The sensing block (110) is rotated by a rotation axis (62c), and a light-emitting sensor (120) and two light-receiving sensors (130, 135) are arranged facing each other around the center of the cylindrical sensing block (110). The signals from the two light-receiving sensors (130, 135) output by the light-emitting sensor (120) are combined by a logic circuit unit (140), the signals from the logic circuit unit (140) are input to an MCU (150), and the MCU (150) counts the signals from the logic circuit unit (140) to calculate the amount of tap water used. The light-emitting sensor (120) and the light-receiving sensors (130, 135) are respectively arranged inside the first sensor housing unit (211) and the second sensor housing unit (212) of a transparent metering case (200). The case (200) is covered by an opaque cover (220), the coupling groove of the coupling portion (215, 216) formed on the side of the inspection case (200) is coupled to the coupling projection (91, 92) of the coupling ring (90), the coupling ring (90) is mounted on the upper outer shell (80), and the first sensor housing portion (211) and the second sensor housing portion (212) of the inspection case (200) are in close contact with the protective cover plate (180), thereby,A water meter characterized by having a block housing portion (181) including a sensing block (110) disposed between a first sensor housing portion (211) including a light-emitting sensor (120) and a second sensor housing portion (212) including light-receiving sensors (130, 135). Claim 2 In claim 1, the sensing block (110) is mounted on the upper end of the rotation axis (62c) of the second gear (62) constituting the gear set (60) and rotates by the rotation axis (62c); a cutting portion (112) is disposed between two arc blocking portions (111, 113); when the arc blocking portions (111, 113) are disposed between the light emitting sensor (120) and the light receiving sensor (130, 135), the light signal provided from the light emitting sensor (120) to the light receiving sensor (130, 135) is blocked by the arc blocking portions (111, 113); and when the cutting portion (112) is disposed between the light emitting sensor (120) and the light receiving sensor (130, 135), the light signal of the light emitting sensor (120) is input to the light receiving sensor (130, 135) through the cutting portion (112). Meter. Claim 3 A water meter according to claim 1, wherein the light receiving sensors (130, 135) are positioned facing the light emitting sensor (120), the two light receiving sensors (130, 135) are spaced apart from each other by a predetermined angle (a) with respect to the light emitting sensor (120), and the two light receiving sensors (130, 135) are positioned within the width range of the cut section (112). Claim 4 In claim 1, when the light signal of the light-emitting sensor (120) is input to both the first and second light-receiving sensors (130, 135) through the cut-out portion (112) of the sensing block (110), the ON signals of the first and second light-receiving sensors (130, 135) are input to the logic circuit portion (140) respectively, and the logic circuit portion (140) outputs a low signal to the MCU (150). When the sensing block (110) rotates so that the light signal of the light-emitting sensor (120) is not input to the first light-receiving sensor (130) by the arc blocking portion (111) of the sensing block (110) but is input to the second light-receiving sensor (135) through the cut-out portion (112) of the sensing block (110), the OFF signal of the first light-receiving sensor (130) and the ON signal of the second light-receiving sensor (135) Each is input to the logic circuit section (140), and the logic circuit section (140) maintains the previous low signal as is. When the sensing block (110) rotates further so that the light signal of the light-emitting sensor (120) is not input to the first light-receiving sensor (130) and the second light-receiving sensor (135) by the arc blocking section (111, 113) of the sensing block (110), the off signal of the first light-receiving sensor (130) and the second light-receiving sensor (135) is input to the logic circuit section (140), and the logic circuit section (140) outputs a high signal. When the sensing block (110) rotates further so that the light signal of the light-emitting sensor (120) is not input to the second light-receiving sensor (135) by the arc blocking section (111) of the sensing block (110), the first A water meter characterized in that when input is received by the light receiving sensor (130), the ON signal of the first light receiving sensor (130) and the OFF signal of the second light receiving sensor (135) are each input to the logic circuit unit (140), and the logic circuit unit (140) maintains the previous high signal. Claim 5 A water meter according to claim 1, characterized in that when a signal is input from the logic circuit (140) to the MCU (150), the MCU (150) counts low signals and high signals at regular time intervals to calculate the water usage amount, displays the calculated water usage amount plus the existing accumulated amount on an indicator, and transmits the water usage amount to the water utility company's server (170) on a fixed date each month. Claim 6 In claim 1, the gear set (60) is coupled to a drive gear (37) coupled to the rotation axis (35) of the impeller (30) with the lower gear (61a) of the first gear (61), a star needle (61d) is mounted on the upper end of the rotation axis (61c) of the first gear (61), the lower gear (62b) of the second gear (62) is coupled to the upper gear (61b) of the first gear (61), a sensing block (110) is mounted on the upper end of the rotation axis (62c) of the second gear (62), the lower gear of the third gear (63) is coupled to the upper gear (62c) of the second gear (62), a 0.1L needle (63d) is mounted on the upper end of the rotation axis (63c) of the third gear (63), the third gear (63) is coupled to the fourth gear (64) through a reduction gear, and the A water meter characterized by having a 1L indicator (64d) mounted on the upper end of the rotation axis (64c) of the 4th gear (64), the 4th gear (64) being linked to the 5th gear (65) through a reduction gear, a 10L indicator (65d) mounted on the upper end of the rotation axis (65c) of the 5th gear (65) being linked to the 6th gear (66) through a reduction gear, a 100L indicator (66d) mounted on the upper end of the rotation axis (66c) of the 6th gear (66), and the 6th gear (66) being linked to the worm gear (71) of the counter wheel unit (70) through an electric gear. Claim 7 A water meter according to claim 1, wherein the gear box (50) has a hole (52) drilled in the upper transparent plate (51), a sensing block (110) protrudes rotatably through the hole (52), and a transparent protective cover plate (180) is in close contact with the upper transparent plate (51), and the sensing block (110) is inserted into the interior of the block housing part (181) formed in the protective cover plate (180). Claim 8 delete Claim 9 A water meter according to claim 1, wherein the meter reading case (200) has a PCB (220) including an MCU (150) and a logic circuit (140) and a power supply battery (230) built in, a light-emitting sensor (120) and a light-receiving sensor (130, 135) mounted on the PCB (220), an indicator (240) for displaying water usage and an NFC antenna (170) for transmitting water usage data to a water utility management server (170). Claim 10 A water meter according to claim 1, characterized in that the meter reading case (200) has an L-shaped neck portion (205) formed on one side of a square portion (203), and a first sensor housing portion (211) and a second sensor housing portion (212) are formed to protrude downward from the neck portion (205).

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