阅读说明：本技术 家用供、排水控制及电压型水位显示器 (Domestic water supply and drainage control and voltage type water level display ) 是由 骆金山 于 2020-01-12 设计创作，主要内容包括：家用供、排水控制及电压型水位显示器,桥堆负极串联保险絲、继电器线圈、二极管负极,二极管正极引出一电路接上水位A点,二极管正极引出另一电路串联继电器常开触点后接下限水位B点。电源接于转换开关输入端、转换开关输出端在继电器常闭触点与常开触点之间转换,继电器转换触点接电机。桥堆正极串联保险絲、限流电阻、二极管、水位电阻串联组。电压表并联于限流电阻示水位。水位至A点,水与桥堆负极间产生电流,继电器吸合,常闭触点断开,水泵停转。水位至B点时,继电器线圈无电流,继电器释放,常闭触点闭合,水泵供水。电源经转换开关接至继电器常开触点,水高时水泵排水,水低时水泵停运。达到供、排水转换。(The negative pole of bridge pile is series-connected with fuse, relay coil and diode negative pole, the positive pole of diode is led out a circuit and connected with upper water level A point, and the positive pole of diode is led out another circuit and connected with normally open contact of relay and then connected with lower water level B point. The power supply is connected with the input end of the change-over switch, the output end of the change-over switch is switched between the normally closed contact and the normally open contact of the relay, and the change-over contact of the relay is connected with the motor. The positive pole of the bridge pile is connected with the fuse wire, the current limiting resistor, the diode and the water level resistor in series. The voltmeter is connected in parallel with the current-limiting resistor to indicate the water level. When the water level reaches the point A, current is generated between the water and the negative pole of the bridge pile, the relay is closed, the normally closed contact is disconnected, and the water pump stops rotating. When the water level reaches the point B, no current flows through the relay coil, the relay is released, the normally closed contact is closed, and water is supplied by the water pump. The power supply is connected to the normally open contact of the relay through the change-over switch, the water pump drains water when the water level is high, and the water pump stops running when the water level is low. So as to achieve the conversion of water supply and drainage.)

1. The utility model provides a domestic confession, drainage control and voltage type water level display, includes rectifier bridge (1), fuse (2), relay coil (3), afterflow pipe (4), ground diode (5), relay normally open contact (6), fuse (7), current-limiting resistance (8), direct voltage meter (9), ground diode (10), water level resistance series group (11), relay normally open contact (12), two-way change over switch (13), relay change over contact (14), water pump motor (15), relay normally closed contact (16), its main characterized in that: the direct current negative pole that alternating current power supply exported through rectifier bridge (1) is established ties in proper order and is had fuse (2), relay coil (3), the negative pole of two takeover of ground connection (5), the positive pole of two takeover of ground connection (5) is arranged at upper limit point (A) of water level department, the positive pole of two takeover of ground connection (5) is established ties relay normally open contact (6) the back end point and is arranged at lower limit point (B) of water level department, continuous flow tube (4) are parallelly connected in relay coil (3) both ends, alternating current power supply connects in two-way change over switch (13) input, two-way change over switch (13) output is used for switching over the hookup between relay normally closed contact (16) and relay normally open contact (12), relay change over contact (14) switch-on water pump motor (15), the direct current positive pole of rectifier bridge (1) is established ties in proper order has fuse (7), resistance (8), earthing diode (10, The water level resistor series group (11) and the direct current voltmeter (9) are connected in parallel with the current limiting resistor (8).

2. The utility model provides a domestic confession, drainage control and voltage type water level display, includes rectifier bridge (1), fuse (2), relay coil (3), afterflow pipe (4), ground diode (5), relay normally open contact (6), fuse (7), current-limiting resistance (8), direct voltage meter (9), ground diode (10), water level resistance series group (11), relay normally open contact (12), two-way change over switch (13), relay change over contact (14), water pump motor (15), relay normally closed contact (16), its main characterized in that: the direct current positive pole of an alternating current power supply output through a rectifier bridge (1) is sequentially connected in series with a fuse wire (2), a relay coil (3), the positive pole of a grounding two-connection pipe (5), one path of end point of the negative pole of the grounding two-connection pipe (5) is arranged at an upper water level limit point (A), the rear end point of a negative pole of the grounding two-connection pipe (5) is arranged at a lower water level limit point (B), a follow current pipe (4) is connected in parallel with the two ends of the relay coil (3), the alternating current power supply is connected with the input end of a bidirectional transfer switch (13), the output end of the bidirectional transfer switch (13) is used for being connected between a normally closed relay contact (16) and a normally open relay contact (12) in a conversion way, the relay transfer contact (14) is connected with a water pump motor (15), the direct current negative pole of the rectifier bridge (1) is sequentially connected in series with a fuse wire (7), the water level resistor series group (11) and the direct current voltmeter (9) are connected in parallel with the current limiting resistor (8).

3. A domestic water supply, drain control and voltage level display as claimed in claim 1, wherein: the rectifier bridge (1) is a single-phase rectifier bridge.

4. A domestic water supply, drain control and voltage level display as claimed in claim 1, wherein: the rectifier bridge (1) is a two-phase rectifier bridge.

5. A domestic water supply, drain control and voltage level display as claimed in claim 1, wherein: the rectifier bridge (1) is a three-phase rectifier bridge. .

Technical Field

The present invention belongs to the field of electric appliance.

Background

The existing technology of controlling the water level by adopting a floating magnet to trigger the closing (or opening) of a reed switch contact is required to be provided with an amplifying power system because the current capacity which can be controlled by the reed switch contact is smaller; and it also has no water level display function.

The greater disadvantage is the lack of versatility, the upper and lower water level difference is fixed, and the water tanks with different heights must be selected with different water level difference controllers.

Disclosure of Invention

The utility model provides a domestic confession, drainage control and voltage type water level display, includes rectifier bridge (1), fuses (2), relay coil (3), afterflow pipe (4), ground diode (5), relay normally open contact (6), fuses (7), current-limiting resistance (8), direct voltage meter (9), ground diode (10), water level resistance series group (11), relay normally open contact (12), two-way change over switch (13), relay change over contact (14), water pump motor (15), relay normally closed contact (16). The direct current negative pole that alternating current power supply exported through rectifier bridge (1) connects in series in proper order has the fuse (2), relay coil (3), the negative pole of two takeover of ground connection (5), the positive pole of two takeover of ground connection (5) one way endpoint sets up in upper limit point of water level (A) department, the positive pole of two takeover of ground connection (5) another way series connection relay normally open contact (6) back endpoint sets up in lower limit point of water level (B) department. The follow current tube (4) is connected in parallel with two ends of the relay coil (3). The alternating current power supply is connected with the input end of the bidirectional transfer switch (13), and the output end of the bidirectional transfer switch (13) is used for being connected between the normally closed contact (16) of the relay and the normally open contact (12) of the relay in a conversion mode. The relay conversion contact (14) is communicated with a water pump motor (15) and the direct current positive pole of the rectifier bridge (1) and is sequentially connected with a fuse (7), a current-limiting resistor (8), a grounding diode (10), a water level resistor series group (11) and a direct current voltmeter (9) in series and connected with the current-limiting resistor (8).

When the water pump needs to supply water, the output end of the bidirectional change-over switch (13) is connected with two normally closed contacts (16) of the relay, the water pump motor (15) operates, and the water pump starts to supply water.

After the rectifier bridge (1) is connected with the AC voltage U, the potential difference between the negative electrode of the DC output and the zero potential of the ground is-0.45U of the AC voltage. The water in the container is conducted with the ground, and the water in the container has the same ground zero potential.

The potential difference between the water in the container and the negative electrode voltage minus 0.45U of the rectifier bridge (1) through the grounding diode (5) is equal to 0.45U.

The potential difference enables the anode to contact the water reaching the upper limit water level (A) in the container and the cathode of the external connection two connecting pipe (5) to generate current through the relay coil (3), the fuse (2) and the cathode of the rectifier bridge (1). The relay coil (2) is energized to operate, the normally closed contact (16) is opened, and the water pump (15) stops supplying water.

When the water level in the container is lower than the lower limit point (B), the current flowing through the relay normally open contact (6), the grounding diode (5), the relay coil (3), the fuse wire (2) and the negative pole of the rectifier bridge (1) disappears, the relay coil (3) loses power and acts, the normally closed contact (16) is closed, and the water pump motor (15) supplies water again.

When the water pump needs to drain water, the water pump motor (15) does not run when not electrified as long as the output end of the change-over switch (13) is connected with the two normally open contacts (12) of the relay.

After the rectifier bridge (1) is connected with the AC voltage U, the potential difference between the negative electrode of the DC output and the zero potential of the ground is-0.45U of the AC voltage. The water in the container is conducted with the ground, and the water in the container has the same ground zero potential.

The potential difference between the water in the container and the negative electrode voltage minus 0.45U of the rectifier bridge (1) through the grounding diode (5) is equal to 0.45U.

The potential difference enables the anode to contact the water reaching the upper limit water level (A) in the container and the cathode of the grounding two-connection pipe (5) to generate current through the relay coil (3), the fuse (2) and the cathode of the rectifier bridge (1). The relay coil is energized to operate, the normally open contact (12) is closed, and the water pump (15) starts to discharge water.

When the water level is lower than the lower limit point (B) in the container, the current flowing through the relay normally open contact (6), the grounding diode (5), the relay coil (3), the fuse wire (2) and the negative pole of the rectifier bridge (1) disappears, the relay coil (3) loses electricity and acts, the normally open contact (12) is disconnected, and the water pump motor (15) stops draining water.

The normally open contact (6) of the relay can still keep the current flowing through the relay coil (3) after the water level is lower than the upper limit point (A) so that the relay is not released.

The direct current positive pole of the rectifier bridge (1) is sequentially connected with a fuse (7), a current-limiting resistor (8), a grounding diode (10), a water level resistor series group (11) and a direct current voltmeter (9) in series and connected with the current-limiting resistor (8) in parallel.

The voltage to ground of the anode of the rectifier bridge (1) is +0.45U of the voltage of the alternating current power supply U, and when the water level in the container reaches the upper limit (A), the current of the anode of the rectifier bridge (1) flowing through the fuse wire (7), the current limiting resistor (8) and the grounding diode (10) is the maximum. The voltage drop at the two ends of the current limiting resistor (8) is also the largest, so that the swing amplitude of the pointer of the direct current voltmeter (9) is the largest, and the position shown by the pointer is marked as the highest water level.

When the water level in the container is reduced to a lower limit point (B), the current flowing through the fuse wire (7), the current-limiting resistor (8), the grounding diode (10) and the water level resistor series group (11) from the positive pole of the rectifier bridge (1) is zero. The voltage drop at the two ends of the current limiting resistor (8) is zero, so that the pointer of the direct current voltmeter (9) returns to zero, and the position shown by the pointer is marked as a zero water level.

Between the highest water level and the zero water level, the actual height of each resistor (R) in the water level resistor series group (11) in the water tank is marked according to the position indicated by the pointer of the voltmeter (9) when the resistor (R) is conducted with water. The real-time height of the water level can be read from the pointer of the voltmeter (9).

The invention can also adopt the two-phase rectifier bridge (1) shown in figure 5 that the negative pole is conducted with the water with zero potential in the container through the fuse wire (2), the relay coil (3) and the grounding two-connection pipe (5) to make the relay act.

The invention can also adopt the three-phase rectifier bridge (1) shown in fig. 6 that the negative pole of the fuse (2), the relay coil (3) and the grounding two-connection pipe (5) are conducted with the zero-potential water in the container to make the relay act.

The invention not only omits a transformer, but also is more reliable because the earth current of the relay coil (2) with high resistance value and the current-limiting resistor (8) can be set to be less than 10MA and far lower than the action current of 30MA of the household leakage protector, and the double safety design of the fuse wire (2) and the fuse wire (7) of 10MA is adopted.

The invention replaces the traditional transformer low-voltage power supply with the method of controlling the high-voltage micro-current to transmit the water level detection signal, thereby having lower line loss and longer transmission distance.

The rectifier bridge (1) can adopt various rectification modes such as a single-phase rectifier bridge, a two-phase rectifier bridge and a three-phase rectifier bridge.

Drawings

FIG. 1: one embodiment of the household water supply, drainage control and water supply of voltage type water level display.

FIG. 2: one embodiment of the household water supply and drainage control and voltage type water level display drainage.

FIG. 3: the second embodiment of the household water supply, drainage control and voltage type water level display.

FIG. 4: the second embodiment of the domestic water supply, water discharge control and voltage type water level display.

FIG. 5: two-phase rectifier bridge circuit diagram.

FIG. 6: three-phase rectifier bridge circuit diagram.

In the figure: 1. rectifier bridge, 2, fuse, 3, relay coil, 4, afterflow tube, 5, earth diode, 6, relay normally open contact, 7, fuse wire, 8, current-limiting resistance, 9, direct-current voltmeter, 10, earth diode, 11, water level resistance series group, 12, relay normally open contact, 13, two-way change over switch, 14, relay change over contact, 15, water pump motor, 16, relay normally closed contact.

Detailed Description

FIG. 1 is an electrical schematic diagram of an embodiment of a household water supply, drain control and water supply of a voltage-type water level display. The direct current negative pole that alternating current power supply exported through rectifier bridge (1) establishes ties in proper order has the fuse (2), relay coil (3), the negative pole of two takeover of ground connection (5), and the positive pole of two takeover of ground connection (9) is terminal point setting in upper limit of water level (A) department all the way, and the positive pole of two takeover of ground connection (5) is another way establishes ties behind relay normally open contact (6) and is set up the terminal point in lower limit of water level (B). The follow current tube (4) is connected in parallel with two ends of the relay coil (3).

Two ends of a water pump motor (15) are respectively connected with two conversion contacts (14) of the relay, two normally closed contacts (16) of the relay are connected with two output ends of the bidirectional conversion switch (13), and two input ends of the bidirectional conversion switch (13) are connected with an alternating current power supply.

After the rectifier bridge (1) is connected with the AC voltage U, the potential difference between the negative electrode of the DC output and the zero potential of the ground is-0.45U of the AC voltage. The water in the container is conducted with the ground, and the water in the container has the same ground zero potential.

The potential difference between the water in the container and the negative electrode voltage minus 0.45U of the rectifier bridge (1) through the external diode (5) is equal to 0.45U.

The potential difference enables the anode to contact with the water at the upper limit water level (A) in the container and the cathode of the grounding two-connection pipe (5) to generate current through the fuse (2), the relay coil (3) and the cathode of the rectifier bridge (1). The relay coil (3) is electrified to act, the normally closed contact (16) is disconnected, and the water pump motor (15) stops rotating.

When the water level in the container is lower than the lower limit point (B), the current flowing through the relay normally open contact (6), the grounding diode (5) and the relay coil (3) disappears, the relay loses electricity to act, the normally closed contact (16) is closed, and the electrified water pump (15) supplies water again.

The relay normally open contact (6) is used for keeping the current flowing through the relay coil (3) to be attracted after the water level is lower than the upper limit point (A).

The direct current positive pole of the rectifier bridge (1) is sequentially connected with a fuse (7), a current-limiting resistor (8), a grounding diode (10), a water level resistor series group (11) and a direct current voltmeter (9) in series and connected with the current-limiting resistor (8) in parallel.

The voltage to ground of the anode of the rectifier bridge (1) is +0.45U of the voltage of the alternating current power supply U, and when the water level in the container reaches the upper limit (A), the current of the anode of the rectifier bridge (1) flowing through the fuse wire (7), the current limiting resistor (8) and the grounding diode (10) is the maximum. The voltage drop at the two ends of the current limiting resistor (8) is also the largest, so that the swing amplitude of the pointer of the direct current voltmeter (9) is the largest, and the position shown by the pointer is marked as the highest water level. When the water level in the container is reduced to a lower limit point (B), the current flowing through the fuse wire (7), the current-limiting resistor (8), the grounding diode (10) and the water level resistor series group (11) from the positive pole of the rectifier bridge (1) is zero. The voltage drop at the two ends of the current limiting resistor (8) is zero, so that the pointer of the direct current voltmeter (9) returns to zero, and the position shown by the pointer is marked as a zero water level.

Between the highest water level and the zero water level, the actual height of each resistor (R) in the water level resistor series group (11) in the water tank is marked according to the position indicated by the pointer of the voltmeter (9) when the resistor (R) is conducted with water. The real-time height of the water level can be read from the pointer of the voltmeter (9).

FIG. 2 shows one embodiment of the water supply and drainage control and voltage level display for domestic use.

When the water pump drains water, the motor of the water pump does not run when the output end of the bidirectional transfer switch (13) is switched to the two normally open contacts (12) of the relay.

After the rectifier bridge (1) is connected with the AC voltage U, the potential difference between the negative electrode of the DC output and the zero potential of the ground is-0.45U of the AC voltage. The water in the container is conducted with the ground, and the water in the container has the same ground zero potential.

The potential difference between the water in the container and the negative electrode voltage minus 0.45U of the rectifier bridge (1) through the grounding diode (5) is equal to 0.45U.

The potential difference enables the anode to contact the water reaching the upper limit water level (A) in the container, the cathode of the grounding two-connection pipe (5) generates current through the safety fuse (2), the relay coil (3) and the cathode of the rectifier bridge (1), the relay coil (3) is electrified and the relay is attracted, the normally open contact (12) is closed, and the water pump (15) starts to drain water.

When the water level in the container is lower than the lower limit point (B), the current flowing through the relay normally open contact (6), the grounding diode (5), the relay coil (3), the fuse wire (2) and the negative pole of the rectifier bridge (1) disappears, the relay is released, the normally open contact (12) is disconnected, and the water pump motor (15) stops draining.

The relay normally open contact (6) is used for continuously keeping the current of the relay coil (3) flowing through after the water level is lower than the upper limit point (A) so as to ensure the relay to maintain the attraction.

The direct current positive pole of the rectifier bridge (1) is sequentially connected with a fuse (7), a current-limiting resistor (8), a grounding diode (10), a water level resistor series group (11) and a direct current voltmeter (9) in series and connected with the current-limiting resistor (8) in parallel.

The voltage to ground of the anode of the rectifier bridge (1) is +0.45U of the voltage of the alternating current power supply U, and when the water level in the container reaches the upper limit (A), the current of the anode of the rectifier bridge (1) flowing through the fuse wire (7), the current limiting resistor (8) and the grounding diode (10) is the maximum. The voltage drop at the two ends of the current limiting resistor (8) is also the largest, so that the swing amplitude of the pointer of the direct current voltmeter (9) is the largest, and the position shown by the pointer is marked as the highest water level. When the water level in the container is reduced to a lower limit point (B), the current flowing through the fuse wire (7), the current-limiting resistor (8), the grounding diode (10) and the water level resistor series group (11) from the positive pole of the rectifier bridge (1) is zero. The voltage drop at the two ends of the current limiting resistor (8) is zero, so that the pointer of the direct current voltmeter (9) returns to zero, and the position shown by the pointer is marked as a zero water level.

Between the highest water level and the zero water level, the actual height of each resistor (R) in the water level resistor series group (11) in the water tank is marked according to the position indicated by the pointer of the voltmeter (9) when the resistor (R) is conducted with water. The real-time height of the water level can be read from the pointer of the voltmeter (9).

FIG. 3 shows a second embodiment of the domestic water supply, drain control and water supply of the voltage level indicator. The direct current positive pole that alternating current power supply exported through rectifier bridge (1) establishes ties in proper order has the fuse (2), relay coil (3), the positive pole of two takeover of ground connection (5), and the negative pole of two takeover of ground connection (5) is terminal point setting in upper limit of water level (A) department all the way, and the negative pole of two takeover of ground connection (5) is another way establishes ties behind relay normally open contact (6) and is set up the terminal point in lower limit of water level (B) department. The follow current tube (4) is connected in parallel with two ends of the relay coil (3).

Two ends of a water pump motor (15) are respectively connected with two conversion contacts (14) of the relay, two normally closed contacts (16) of the relay are connected with two output ends of the bidirectional conversion switch (13), and two input ends of the bidirectional conversion switch (13) are connected with an alternating current power supply.

After the rectifier bridge (1) is connected with the AC voltage U, the potential difference between the positive electrode of the DC output and the zero potential of the ground is +0.45U of the AC voltage. The water in the container is conducted with the ground, and the water in the container has the same ground zero potential.

The potential difference between the water in the container and the positive voltage +0.45U of the rectifier bridge (1) through the external diode (5) is equal to 0.45U. The potential difference enables the positive electrode of the grounding two-connection pipe (5) which is contacted with water at the upper limit water level (A) in the container to generate current through the fuse wire (2), the relay coil (3) and the positive electrode of the rectifier bridge (1). The relay coil (3) is electrified to act, the normally closed contact (16) is disconnected, and the water pump motor (15) stops rotating.

When the water level in the container is lower than the lower limit point (B), the current flowing through the relay normally open contact (6), the grounding diode (5) and the relay coil (3) disappears, the relay loses electricity to act, the normally closed contact (16) is closed, and the electrified water pump (15) supplies water again.

The relay normally open contact (6) is used for keeping the current flowing through the relay coil (3) to be attracted after the water level is lower than the upper limit point (A).

The direct current negative pole of the rectifier bridge (1) is sequentially connected with a fuse (7), a current-limiting resistor (8), a grounding diode (10), a water level resistor series group (11) and a direct current voltmeter (9) in series and connected with the current-limiting resistor (8) in parallel.

The ground voltage of the negative electrode of the rectifier bridge (1) is-0.45U of that of an alternating current power supply U, and when the water level in the container reaches an upper limit (A), the current of the negative electrode of the rectifier bridge (1) flowing through the fuse wire (7), the current limiting resistor (8) and the grounding diode (10) is the maximum. The voltage drop at the two ends of the current limiting resistor (8) is also the largest, so that the swing amplitude of the pointer of the direct current voltmeter (9) is the largest, and the position shown by the pointer is marked as the highest water level. When the water level in the container is reduced to a lower limit point (B), the current flowing through the fuse (7), the current-limiting resistor (8) and the grounding diode (10) from the negative electrode of the rectifier bridge (1) is zero. The voltage drop at the two ends of the current limiting resistor (8) is zero, so that the pointer of the direct current voltmeter (9) returns to zero, and the position shown by the pointer is marked as a zero water level.

Between the highest water level and the zero water level, the actual height of each resistor (R) in the water level resistor series group (11) in the water tank is marked according to the position shown by the pointer of the voltmeter when the resistor (R) is conducted with water. The real-time height of the water level can be read from the indication of the pointer of the voltmeter.

FIG. 4 shows a second embodiment of the water supply and drainage control and voltage level display for domestic use. When the water pump drains water, the motor of the water pump does not run when the output end of the bidirectional transfer switch (13) is switched to the two normally open contacts (12) of the relay.

After the rectifier bridge (1) is connected with the AC voltage U, the potential difference between the positive electrode of the DC output and the zero potential of the ground is +0.45U of the AC voltage. The water in the container is conducted with the ground, and the water in the container has the same ground zero potential.

The potential difference between the water in the container and the positive voltage +0.45U of the rectifier bridge (1) through the grounding diode (5) is equal to 0.45U.

The potential difference enables the positive pole of the grounding two-connection pipe (5) which is in contact with water reaching the upper limit water level (A) in the container to generate current through the fuse (2), the relay coil (3) and the positive pole of the rectifier bridge (1), the relay coil (3) is electrified and the relay is attracted, the normally open contact (12) is closed, and the water pump (15) starts to drain water.

When the water level in the container is lower than the lower limit point (B), the current flowing through the relay normally open contact (6), the grounding diode (5), the relay coil (3), the fuse wire (2) and the anode of the rectifier bridge (1) disappears, the relay is released, the normally open contact (12) is disconnected, and the water pump motor (15) stops draining water.

The relay normally open contact (6) is used for continuously keeping the current of the relay coil (3) flowing through after the water level is lower than the upper limit point (A) so as to ensure the relay to maintain the attraction.

The direct current negative pole of the rectifier bridge (1) is sequentially connected with a fuse (7), a current-limiting resistor (8), a grounding diode (10), a water level resistor series group (11) and a direct current voltmeter (9) in series and connected with the current-limiting resistor (8) in parallel.

The ground voltage of the negative electrode of the rectifier bridge (1) is-0.45U of that of an alternating current power supply U, and when the water level in the container reaches an upper limit (A), the current of the negative electrode of the rectifier bridge (1) flowing through the fuse wire (7), the current limiting resistor (8) and the grounding diode (10) is the maximum. The voltage drop at the two ends of the current limiting resistor (8) is also the largest, so that the swing amplitude of the pointer of the direct current voltmeter (9) is the largest, and the position shown by the pointer is marked as the highest water level. When the water level in the container is reduced to a lower limit point (B), the current flowing through the fuse (7), the current-limiting resistor (8), the grounding diode (10) and the water level resistor series group (11) from the negative electrode of the rectifier bridge (1) is zero. The voltage drop at the two ends of the current limiting resistor (8) is zero, so that the pointer of the direct current voltmeter (9) returns to zero, and the position shown by the pointer is marked as a zero water level.

Between the highest water level and the zero water level, the actual height of each resistor (R) in the water level resistor series group (11) in the water tank is marked according to the position indicated by the pointer of the voltmeter (9) when the resistor (R) is conducted with water. The real-time height of the water level can be read from the pointer of the voltmeter (9).

The relay normally open contact (6) is used for continuously keeping the current of the relay coil (3) flowing through after the water level is lower than the upper limit point (A) so as to ensure the relay to maintain the attraction.

The invention can also adopt the two-phase rectifier bridge (1) shown in figure 5 that the positive pole of the wire (2) is connected with the zero potential water in the container through the fuse wire (3), the grounding two-connection pipe (5) to make the relay act.

The invention can also adopt the three-phase rectifier bridge (1) shown in figure 6 that the positive pole of the fuse (2), the relay coil (3) and the grounding two-connection pipe (5) are conducted with the zero-potential water in the container to make the relay act.

The invention not only omits a transformer, but also is more reliable because the earth current of the relay coil (2) with high resistance value and the current-limiting resistor (8) can be set to be less than 10MA and far lower than the action current of 30MA of the household leakage protector, and the double safety design of the fuse wire (2) and the fuse wire (7) of 10MA is adopted.

The invention uses the method of controlling the high-voltage micro-current to replace the low-voltage power supply of the transformer to transmit the water level detection signal, and the transmission distance is longer because the line loss is lower.

The invention has universality, and can adopt the same household water supply and drainage control and water level display regardless of the height difference of the upper water level and the lower water level of the water tank.

The rectifier bridge (1) can adopt various rectification modes such as a single-phase rectifier bridge, a two-phase rectifier bridge and a three-phase rectifier bridge.