CN216254787U - Automatic water changing device for aquarium - Google Patents

Abstract

The utility model discloses an automatic water changing device for an aquarium, which comprises a piston frame, an electromagnetic valve group, a circuit board and a check valve group, wherein a sealed piston rod is movably inserted in the middle of the piston frame, two ends of the piston rod are fixedly connected with pistons, two sides of the piston frame are respectively sleeved with a cylinder barrel, the top end of a first water inlet hole is fixedly communicated with a first water injection pipe, one end of the first water injection pipe is fixedly communicated with one side of the electromagnetic valve group, the top end of the electromagnetic valve group is fixedly communicated with a water inlet pipe of the aquarium, the bottom end of the electromagnetic valve group is fixedly communicated with a clean water inlet circulating pipe, one end of the clean water inlet circulating pipe is fixedly communicated with a flow switch, the input end of the flow switch is fixedly communicated with a clean water inlet pipe, and the flow switch is electrically connected with the circuit board, municipal tap water pressure is used as automatic water changing power, and automatic water changing of the fish tank is achieved.

Description

Automatic water changing device for aquarium

Technical Field

The utility model relates to the technical field of automatic water changing devices for fish tanks, in particular to an automatic water changing device for an aquarium.

Background

In the aspect of aquarium fish culture, the fish tank water body is polluted due to the food left after feeding, the excrement generated by the fish, the moss generated after sunlight or lamplight irradiation and the like, and the fish tank needs to be changed once in a week to a month according to the types, sizes and quantity of the fish in the fish tank. Over time, the water body is in an incremental process with constant contamination, which can lead to fish morbidity or mortality if the water is not replaced in time. At present, the water change of the fish tank is basically carried out by pure manual operation and a device for automatically adding water by a floating ball.

The mode of pure manual water changing can consume a large amount of time, manpower to because the staff is the stage, just change water once of going on in the longer time, in the time cycle of changing water twice, the water is in the process that the pollution constantly deepens, and some fish that require higher to the quality of water is raised the degree of difficulty than great, can only constantly shorten the cycle of changing water, increase work load.

Utilize the automatic watered mode of floater, owing to not integrating into the sewage function of will taking out, sewage still need the manual work to take away, just can add water, has only alleviateed the work load of intaking, optimizes under this scheme condition, increases the suction pump and realizes the blowdown function of drawing water, nevertheless is subject to the influence that the fish bowl placed the position, under the condition that the building fitment has been accomplished, increases a big drain pipe, can influence the whole of fitment environment beautifully undoubtedly. Because the fish tank is generally away from a building water outlet by a certain distance, the overlong thin pipe is used as a water outlet pipe, and because of the influence of pipeline resistance, a high-pressure water pump is needed to adapt to a wider use environment. The use of a high pressure water pump may cause an increase in cost, an increase in operating noise, an increase in energy consumption, and a conditional limitation on the life of the water pump. And the high-pressure water pump needs to be matched with a Hall flowmeter to control the water change amount, and simultaneously, higher cost and circuit control complexity are brought.

The two water changing modes are both to control the water changing amount at one time. In winter, the water is changed too much once, which causes the water temperature or water quality in the fish tank to change too much, and the fish can not adapt to the change, thereby causing death.

SUMMERY OF THE UTILITY MODEL

The utility model aims to provide an automatic water changing device for an aquarium, which aims to solve the problems in the background technology.

In order to achieve the purpose, the utility model provides the following technical scheme: an automatic water changing device for an aquarium comprises a piston frame, an electromagnetic valve group, a circuit board and a check valve group, wherein a sealed piston rod is movably inserted in the middle of the piston frame, pistons are fixedly connected to two ends of the piston rod, cylinder barrels are sleeved on two sides of the piston frame, inner cavities of the two cylinder barrels are divided into a W1 cavity, a G1 cavity, a G2 cavity and a W2 cavity by the two pistons, a first water inlet and outlet hole and a second water inlet and outlet hole are respectively formed in two ends of one side of the piston frame, a first water injection pipe is fixedly communicated with the top end of the first water inlet and outlet hole, one end of the first water injection pipe is fixedly communicated with one side of the electromagnetic valve group, a second water injection pipe is fixedly communicated with one end of the second water inlet and outlet hole, one end of the second water injection pipe is fixedly communicated with the other side of the electromagnetic valve group, a aquarium water inlet pipe is fixedly communicated with the top end of the electromagnetic valve group, and a clean water inlet pipe is fixedly communicated with the bottom end of the electromagnetic valve group, the fixed intercommunication of one end of clean inlet flow pipe has flow switch, the fixed intercommunication of flow switch's input has clean water inlet tube, flow switch and circuit board electric connection, the fixed intercommunication in one side in W1 chamber has first sewage suction tube, the one end of first sewage suction tube and the one end fixed connection of check valves, the fixed intercommunication in one side that W1 chamber was kept away from in W2 chamber has second sewage suction tube, the fixed intercommunication in one end that first sewage suction tube was kept away from to the one end of second sewage suction tube and check valves, the fixed intercommunication in top of check valves has sewage discharge pipe, the bottom mounting intercommunication of check valves has sewage suction header pipe.

Preferably, the two pistons are respectively connected in a sliding manner in the inner cavities of the two cylinders, the first water inlet and outlet hole is communicated with the G1 cavity, and the second water inlet and outlet hole is communicated with the G2 cavity.

Preferably, the solenoid valve group comprises an S1 solenoid valve, an S2 solenoid valve, an S3 solenoid valve, an S4 solenoid valve and a solenoid valve communication pipe, the S1 solenoid valve, the S2 solenoid valve, the S3 solenoid valve and the S4 solenoid valve are sequentially and fixedly communicated through the solenoid valve communication pipe, the communication position of the first water injection pipe and the solenoid valve communication pipe is located between the S1 solenoid valve and the S2 solenoid valve, the communication position of the second water injection pipe and the solenoid valve communication pipe is located between the S3 solenoid valve and the S4 solenoid valve, the communication position of the fish bowl water inlet pipe and the solenoid valve communication pipe is located between the S1 solenoid valve and the S3 solenoid valve, and the communication position of the clean water inlet communication pipe and the solenoid valve communication pipe is located between the S2 solenoid valve and the S4 solenoid valve.

Preferably, the check valve group comprises a Z1 check valve, a Z2 check valve, a Z3 check valve, a Z4 check valve and a check valve communicating pipe, wherein the Z1 check valve, the Z2 check valve, the Z3 check valve and the Z4 check valve are fixedly communicated through the check valve communicating pipe in sequence, the communication position of the first sewage suction pipe and the check valve communicating pipe is positioned between the Z1 check valve and the Z2 check valve, the communication position of the second sewage suction pipe and the check valve communicating pipe is positioned between the Z3 check valve and the Z4 check valve, the communication position of the sewage suction collecting pipe and the check valve communicating pipe is positioned between the Z1 check valve and the Z4 check valve, and the communication position of the sewage discharge pipe and the check valve communicating pipe is positioned between the Z2 check valve and the Z3 check valve.

Preferably, the S1 solenoid valve, the S2 solenoid valve, the S3 solenoid valve and the S4 solenoid valve are all electrically connected to a circuit board, a switch button and an adjusting knob are disposed on the surface of the circuit board, and the circuit board is electrically connected to an external power supply through the switch button.

Compared with the prior art, the utility model has the beneficial effects that:

the S1 electromagnetic valve, the S2 electromagnetic valve, the S3 electromagnetic valve and the S4 electromagnetic valve are controlled to be switched off and on through a circuit board, the water flow direction is controlled through the unidirectional flow characteristics of the Z1 check valve, the Z2 check valve, the Z3 check valve and the Z4 check valve, municipal tap water pressure is used as power, automatic water changing of the fish tank is achieved, energy is saved, reliability is high, the reversing frequency of the electromagnetic valve group in each water changing period is adjusted according to the actual use scene of the fish tank, under the condition that municipal tap water has water pressure, the unattended automatic small-quantity and frequent water changing function can be achieved, under the condition, manual water changing work can be replaced, better water quality and feeding environment can be provided for ornamental fish, and the fish culturing survival rate is improved.

Drawings

FIG. 1 is a schematic diagram of the present invention;

FIG. 2 is a cross-sectional view of the cylinder barrel of the present invention;

FIG. 3 is a schematic plan view of the solenoid valve assembly of the present invention;

fig. 4 is a plan view of a check valve pack of the present invention.

In the figure: 1. a piston frame; 2. a piston rod; 3. a piston; 4. a cylinder barrel; 5. a first water inlet and outlet hole; 6. a second water inlet and outlet hole; 7. a W1 cavity; 8. a G1 cavity; 9. a G2 cavity; 10. a W2 cavity; 11. an electromagnetic valve group; 12. a second water injection pipe; 13. a water inlet pipe of the fish tank; 14. cleaning a water inlet circulation pipe; 15. a flow switch; 16. a circuit board; 17. an S1 solenoid valve; 18. an S2 solenoid valve; 19. an S3 solenoid valve; 20. an S4 solenoid valve; 21. a first sewage suction pipe; 22. a check valve group; 23. a second sewage suction pipe; 24. a sewage suction header pipe; 25. a sewage discharge pipe; 26. a Z1 check valve; 27. a Z2 check valve; 28. a Z3 check valve; 29. a Z4 check valve; 30. a check valve communicating pipe; 31. an electromagnetic valve communicating pipe; 32. a clean water inlet pipe; 33. a first water injection pipe.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Referring to fig. 1-4, the present invention provides an automatic water changing device for an aquarium, including a piston frame 1, an electromagnetic valve set 11, a circuit board 16 and a check valve set 22, wherein a sealed piston rod 2 is movably inserted in the middle of the piston frame 1, both ends of the piston rod 2 are fixedly connected with pistons 3, both sides of the piston frame 1 are sleeved with cylinder barrels 4, and the two pistons 3 divide the inner cavity of the two cylinder barrels 4 into a W1 cavity 7, a G1 cavity 8, a G2 cavity 9 and a W2 cavity 10, both ends of one side of the piston frame 1 are respectively provided with a first water inlet and outlet hole 5 and a second water inlet and outlet hole 6, the top end of the first water inlet and outlet hole 5 is fixedly communicated with a first water injection pipe 33, one end of the first water injection pipe 33 is fixedly communicated with one side of the electromagnetic valve set 11, one end of the second water inlet and outlet hole 6 is fixedly communicated with a second water injection pipe 12, one end of the second water injection pipe 12 is fixedly communicated with the other side of the electromagnetic valve set 11, the fixed intercommunication in top of electromagnetism valves 11 has fish bowl inlet tube 13, the bottom mounting intercommunication of electromagnetism valves 11 has clean intake runner 14, the fixed intercommunication in one end of clean intake runner 14 has flow switch 15, the fixed intercommunication in input of flow switch 15 has clean water inlet tube 32, flow switch 15 and circuit board 16 electric connection, the fixed intercommunication in one side of W1 chamber 7 has first sewage suction tube 21, the one end of first sewage suction tube 21 and the one end fixed connection of check valves 22, the fixed intercommunication in one side that W2 chamber 10 kept away from W1 chamber 7 has second sewage suction tube 23, the fixed intercommunication in one end and the check valves 22 of second sewage suction tube 23 keep away from the one end of first sewage suction tube 21, the fixed intercommunication in top of check valves 22 has sewage discharge pipe 25, the bottom mounting intercommunication of check valves 22 has sewage suction manifold 24.

When the device is used, the circuit board 16 controls the S2 electromagnetic valve 18 and the S3 electromagnetic valve 19 to be electrified, the two water pipelines are connected, the S1 electromagnetic valve 17 and the S4 electromagnetic valve 20 are continuously in a closed state, municipal tap water is injected into the G1 cavity 8 through the S2 electromagnetic valve 18, the two pistons 3 slide towards the W1 cavity 7 under the action of water pressure, at the moment, the space of the W1 cavity 7 and the G2 cavity 9 is compressed by the pistons 3, the space of the W2 cavity 10 is expanded to form vacuum suction, and sewage in the W1 cavity 7 can only flow to an outdoor water outlet from the Z2 check valve 27; the vacuum suction force formed by the W2 cavity 10 can only suck the sewage in the fish tank into the cavity from the Z4 check valve 29 pipeline; clean water in a G2 cavity 9 is injected into the fish tank from an opened S3 electromagnetic valve 19, when a W1 cavity 7 is compressed to the bottom and a piston 3 cannot move any more, the pressure of a G1 cavity 8 is balanced with the pressure of municipal tap water, water injection is finished, water inflow is stopped, at the moment, a flow switch 15 is disconnected, signals are transmitted to a circuit board 16, the circuit board 16 receives instructions to perform reversing, an S2 electromagnetic valve 18 and an S3 electromagnetic valve 19 are closed, an S1 electromagnetic valve 17 and an S4 electromagnetic valve 20 are opened, municipal tap water is injected into a G2 cavity 9 through the S4 electromagnetic valve 20, two pistons 3 move towards a W2 cavity 10 direction under the action of water pressure, at the moment, the W2 cavity 10 and the G1 cavity 8 space are compressed, the W1 cavity 7 space is expanded to form vacuum suction force, sewage in the W2 cavity 10 can only flow to an outdoor water discharge port from a Z3 check valve 28, suction force is formed in the W1 cavity 7, and sewage in the fish tank can only be sucked into the Z1 check valve 26 pipeline; clean water in a G1 cavity 8 is injected into the fish tank from an opened S1 electromagnetic valve 17, when the W2 cavity 10 is compressed to the bottom and the piston 3 can not move any more, the pressure of the G2 cavity 9 is balanced with the pressure of municipal tap water, water injection is finished, and water inlet is stopped; at this time, the flow switch 15 cuts off the signal transmission to the circuit board 16, and the circuit board 16 receives the instruction to perform the reversing; the reversing steps of the two electromagnetic valve groups 11 form a cycle, the cycle on-off of the electromagnetic valves is continuously repeated, the uninterrupted water inlet and sewage discharge functions can be realized, when the cycle times of the electromagnetic valve groups 11 reach a set value, the water change capacity meets the requirement, the system is dormant, and the next cycle is awakened after waiting for 24 hours.

The two pistons 3 slide in the inner cavities of the two cylinders 4 respectively, the first water inlet and outlet hole 5 is communicated with the G1 cavity 8, and the second water inlet and outlet hole 6 is communicated with the G2 cavity 9.

When the device is used, municipal tap water is injected into the G1 cavity 8 through the clean water inlet pipe 32, the clean water inlet circulating pipe 14, the S2 electromagnetic valve 18 and the first water inlet and outlet hole 5, the two pistons 3 move towards the W1 cavity 7 under the action of water pressure, at the moment, the space of the W1 cavity 7 and the G2 cavity 9 is compressed by the pistons 3, the space of the W2 cavity 10 is expanded to form vacuum suction, and sewage in the W1 cavity 7 can only flow to the sewage discharge pipe 25 from the first sewage suction pipe 21 and the Z2 check valve 27; the suction force formed by the W2 cavity 10 can only suck the sewage of the fish tank into the W2 cavity 10 from the sewage suction collecting pipe 24, the Z4 check valve 29 and the second sewage suction pipe 23; clean water in the G2 cavity 9 is injected into the fish tank from the opened S3 electromagnetic valve 19 and the fish tank water inlet pipe 13.

The solenoid valve group 11 includes an S1 solenoid valve 17, an S2 solenoid valve 18, an S3 solenoid valve 19, an S4 solenoid valve 20 and a solenoid valve communication pipe 31, the S1 solenoid valve 17, the S2 solenoid valve 18, the S3 solenoid valve 19 and the S4 solenoid valve 20 are fixedly communicated through the solenoid valve communication pipe 31 in sequence, a communication position of the first water injection pipe 33 and the solenoid valve communication pipe 31 is located between the S1 solenoid valve 17 and the S2 solenoid valve 18, a communication position of the second water injection pipe 12 and the solenoid valve communication pipe 31 is located between the S3 solenoid valve 19 and the S4 solenoid valve 20, a communication position of the fish bowl water inlet pipe 13 and the solenoid valve communication pipe 31 is located between the S1 solenoid valve 17 and the S3 solenoid valve 19, and a communication position of the clean water inlet flow pipe 14 and the solenoid valve communication pipe 31 is located between the S2 solenoid valve 18 and the S4 solenoid valve communication pipe 20.

When the electromagnetic valve group 11 is used, the flow direction of clean water is controlled by switching on and off the electromagnetic valve group 11 through the circuit board 16, and the uninterrupted water inlet and sewage discharge functions can be realized.

The check valve group 22 includes a Z1 check valve 26, a Z2 check valve 27, a Z3 check valve 28, a Z4 check valve 29, and a check valve communication pipe 30, the Z1 check valve 26, the Z2 check valve 27, the Z3 check valve 28, and the Z4 check valve 29 are fixedly communicated sequentially by the check valve communication pipe 30, a communication point of the first sewage suction pipe 21 with the check valve communication pipe 30 is located between the Z1 check valve 26 and the Z2 check valve 27, a communication point of the second sewage suction pipe 23 with the check valve communication pipe 30 is located between the Z3 check valve 28 and the Z4 check valve 29, a communication point of the sewage suction collection pipe 24 with the check valve communication pipe 30 is located between the Z1 check valve 26 and the Z4 check valve 29, and a communication point of the sewage discharge pipe 25 with the check valve communication pipe 30 is located between the Z2 check valve 27 and the Z3 check valve 28.

When the fish tank sewage suction device is used, the sewage flow direction is controlled through the characteristic that the Z1 check valve 26, the Z2 check valve 27, the Z3 check valve 28 and the Z4 check valve 29 can only flow in one direction, so that the sewage in the fish tank can be sucked.

The S1 solenoid valve 17, the S2 solenoid valve 18, the S3 solenoid valve 19 and the S4 solenoid valve 20 are electrically connected to the circuit board 16, a switch button and an adjusting knob are disposed on the surface of the circuit board 16, and the circuit board 16 is electrically connected to an external power source through the switch button.

When in specific use, the circuit board 16 is started once by adopting the automatic wake-up system at intervals of 24 hours, and the on-off times of the electromagnetic valve can be calculated, according to the water volume changed once by the on-off electromagnetic valve, the water volume changed once is calculated in a simulation way, when the circulation interval time of the circuit board 16 is met, the circuit board 16 system is awakened from a dormant state, the circuit is powered on, the S2 electromagnetic valve 18 and the S3 electromagnetic valve 19 are powered on, the S1 electromagnetic valve 17 and the S4 electromagnetic valve 20 are continuously in a closed state, municipal tap water is injected into the G1 cavity 8 through the clean water inlet pipe 32, the clean water inlet circulating pipe 14, the S2 electromagnetic valve 18 and the first water inlet and outlet hole 5, the two pistons 3 move towards the W1 cavity 7 under the action of water pressure, at the moment, the space of the W1 chamber 7 and the G2 chamber 9 is compressed by the piston 3, the space of the W2 chamber 10 is expanded to form vacuum suction force, and the sewage in the W1 chamber 7 can only flow from the first sewage suction pipe 21 and the Z2 check valve 27 to the sewage discharge pipe 25; the suction force formed by the W2 cavity 10 can only suck the sewage in the fish tank into the W2 cavity 10 through the sewage suction collecting pipe 24, the Z4 check valve 29 and the second sewage suction pipe 23; clean water in the G2 cavity 9 is injected into the fish tank from the opened S3 electromagnetic valve 19 and the fish tank water inlet pipe 13, when the cavity of the W1 cavity 7 is compressed to the bottom by the piston 3 and the piston 3 can not move any more, the pressure of the G1 cavity 8 is balanced with the municipal tap water pressure, water injection is finished, water inflow is stopped, at the moment, the flow switch 15 is disconnected from the signal to the circuit board 16, the circuit board 16 receives a command to output and reverse, the S2 electromagnetic valve 18 and the S3 electromagnetic valve 19 are closed, the S1 electromagnetic valve 17 and the S4 electromagnetic valve 20 are opened, the municipal tap water is injected into the G2 cavity 9 through the S4 electromagnetic valve 20, the two pistons 3 move towards the W2 cavity 10 under the action of the water pressure, at the moment, the W2 cavity 10 and the G1 cavity 8 space are compressed, the W1 suction cavity 7 space is expanded to form vacuum, the W2 cavity 10 sewage can only flow to an outdoor water outlet from the Z3 check valve 28, the W1 cavity 7 forms suction force, and the sewage of the fish tank can only be sucked into the W1 cavity 7 from the Z1 check valve 26 pipeline; clean water in a G1 cavity 8 is injected into the fish tank from an opened S1 electromagnetic valve 17, when a W2 cavity 10 is compressed to the bottom by a piston 3 and the piston 3 can not move any more, the pressure of a G2 cavity 9 is balanced with the pressure of municipal tap water, water injection is finished, water inflow is stopped, the steps form a cycle, the electromagnetic valve is continuously switched on and off, uninterrupted water inflow and pollution discharge functions can be realized, and when the cycle times of the electromagnetic valve group 11 reach a set value, the water change capacity meets the requirements. The system sleeps and waits for the next cycle to wake up after 24 hours.

Although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that various changes in the embodiments and/or modifications of the utility model can be made, and equivalents and modifications of some features of the utility model can be made without departing from the spirit and scope of the utility model.

Claims (5)

1. The utility model provides an automatic water installation that trades of aquarium fish bowl, includes piston frame (1), electromagnetism valves (11), circuit board (16) and check valves (22), its characterized in that: the piston rod (2) which is sealed is movably inserted in the middle of the piston frame (1), pistons (3) are fixedly connected to two ends of the piston rod (2), cylinder barrels (4) are sleeved on two sides of the piston frame (1), inner cavities of the two cylinder barrels (4) are divided into a W1 cavity (7), a G1 cavity (8), a G2 cavity (9) and a W2 cavity (10) by the two pistons (3), a first water inlet and outlet hole (5) and a second water inlet and outlet hole (6) are respectively formed in two ends of one side of the piston frame (1), a first water injection pipe (33) is fixedly communicated with the top end of the first water inlet and outlet hole (5), one end of the first water injection pipe (33) is fixedly communicated with one side of the electromagnetic valve group (11), one end of the second water injection pipe (12) is fixedly communicated with the other side of the electromagnetic valve group (11), the fish tank water inlet pipe (13) is fixedly communicated with the top end of the electromagnetic valve group (11), the bottom end of the electromagnetic valve group (11) is fixedly communicated with a clean water inlet circulating pipe (14), one end of the clean water inlet circulating pipe (14) is fixedly communicated with a flow switch (15), the input end of the flow switch (15) is fixedly communicated with a clean water inlet pipe (32), the flow switch (15) is electrically connected with a circuit board (16), one side of a W1 cavity (7) is fixedly communicated with a first sewage suction pipe (21), one end of the first sewage suction pipe (21) is fixedly connected with one end of a check valve group (22), one side of the W2 cavity (10) far away from the W1 cavity (7) is fixedly communicated with a second sewage suction pipe (23), one end of the second sewage suction pipe (23) is fixedly communicated with one end of the check valve group (22) far away from the first sewage suction pipe (21), the top end of the check valve group (22) is fixedly communicated with a sewage discharge pipe (25), and the bottom end of the check valve group (22) is fixedly communicated with a sewage suction manifold pipe (24).

2. An automatic water changing device for an aquarium according to claim 1, wherein: the two pistons (3) are respectively connected in a sliding manner in the inner cavities of the two cylinder barrels (4), the first water inlet and outlet hole (5) is communicated with a G1 cavity (8), and the second water inlet and outlet hole (6) is communicated with a G2 cavity (9).

3. An automatic water changing device for an aquarium according to claim 1, wherein: the electromagnetic valve group (11) comprises an S1 electromagnetic valve (17), an S2 electromagnetic valve (18), an S3 electromagnetic valve (19), an S4 electromagnetic valve (20) and an electromagnetic valve communicating pipe (31), the S1 electromagnetic valve (17), the S2 electromagnetic valve (18), the S3 electromagnetic valve (19) and the S4 electromagnetic valve (20) are fixedly communicated through an electromagnetic valve communicating pipe (31) in sequence, the communication position of the first water injection pipe (33) and the solenoid valve communication pipe (31) is positioned between the S1 solenoid valve (17) and the S2 solenoid valve (18), the communication position of the second water injection pipe (12) and the solenoid valve communication pipe (31) is positioned between the S3 solenoid valve (19) and the S4 solenoid valve (20), the communication position of the fish tank water inlet pipe (13) and the electromagnetic valve communication pipe (31) is positioned between the S1 electromagnetic valve (17) and the S3 electromagnetic valve (19), the communication position of the clean water inlet circulation pipe (14) and the electromagnetic valve communication pipe (31) is positioned between the S2 electromagnetic valve (18) and the S4 electromagnetic valve (20).

4. An automatic water changing device for an aquarium according to claim 1, wherein: the check valve group (22) comprises a Z1 check valve (26), a Z2 check valve (27), a Z3 check valve (28), a Z4 check valve (29) and a check valve communicating pipe (30), the Z1 check valve (26), the Z2 check valve (27), the Z3 check valve (28) and the Z4 check valve (29) are fixedly communicated through a check valve communicating pipe (30) in sequence, the communication position of the first sewage suction pipe (21) and the check valve communication pipe (30) is positioned between the Z1 check valve (26) and the Z2 check valve (27), the communication position of the second sewage suction pipe (23) and the check valve communicating pipe (30) is positioned between the Z3 check valve (28) and the Z4 check valve (29), the communication position of the sewage suction collecting pipe (24) and the check valve communicating pipe (30) is positioned between the Z1 check valve (26) and the Z4 check valve (29), the communication position of the sewage discharge pipe (25) and the check valve communication pipe (30) is positioned between the Z2 check valve (27) and the Z3 check valve (28).

5. An automatic water changing device for an aquarium according to claim 3, wherein: the S1 solenoid valve (17), the S2 solenoid valve (18), the S3 solenoid valve (19) and the S4 solenoid valve (20) are all electrically connected with the circuit board (16), a switch button and an adjusting knob are arranged on the surface of the circuit board (16), and the circuit board (16) is electrically connected with an external power supply through the switch button.

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