Energy-saving closed electrochemical equipment for treating circulating cooling water

Abstract

The utility model discloses energy-saving closed electrochemical equipment for treating circulating cooling water. An integrated multi-gap plate-shaped scale scraping device is adopted for scale removal of the cathode of the equipment, so that the mechanical strength can be remarkably improved, a mutual supporting effect exists between the scale scraping device and the cathode, the scale scraping device is not prone to deformation, the clear distance between the adjacent cathode and anode can be shortened to about 5mm to the minimum, ohm voltage drop and energy consumption are remarkably reduced, and the size of the electrochemical equipment is greatly reduced; the lower surface of the integrated multi-gap plate-shaped scale scraping device is positioned below the water surface of a main water tank of the electrochemical equipment, so that the water tank can be effectively sealed, explosive or harmful substances such as hydrogen, oxygen and chlorine generated on a cathode and an anode are prevented from being diffused around the water tank, and the operation safety is remarkably improved.

Description

Technical Field

[0001] The utility model belongs to an electrochemical treatment device in the technical field of water treatment, in particular to an energy-saving and enclosed electrochemical treatment device for circulating cooling water treatment. Background Technique

[0002] With the characteristics of high efficiency, environmental protection and simple operation, the electrochemical treatment technology has become an important technology for industrial circulating cooling water treatment. During the treatment process, a large amount of scale will deposit on the cathode. When the scale deposits to a certain thickness, it needs to be cleaned in time to ensure the cleanliness of the cathode. Otherwise, it will affect the efficiency of the circulating cooling water electrochemical device in removing hardness, resulting in an increase in the operating voltage of the electrochemical device, a sharp increase in energy consumption, and even the failure of the electrochemical device.

[0003] Currently, the commonly used descaling methods for electrochemical devices include high-pressure water flushing, electrode reversal, mechanical scale scraping, etc. The high-pressure water flushing method will generate a large amount of water mist, the operating environment is poor, and the installation requirements are extremely high. The electrode reversal method is easy to damage the electrodes, and DSA electrodes are required for both the anode and the cathode, with a high cost. Currently, the mechanical scale scraping method is widely used, but it also has obvious disadvantages: (1) During the scale scraping process, the scraper has to bear a large mechanical load, and each scraper is independent, which is easy to cause problems such as scraper fracture and bending deformation. Therefore, in order to improve the mechanical strength, scrapers with larger sizes are usually used, which significantly increases the distance between adjacent cathodes and anodes, resulting in a substantial increase in ohmic voltage drop and energy consumption; (2) The treatment device is open, and the hydrogen, oxygen and chlorine generated during the operation are directly emitted to the surrounding of the treatment device, posing a large safety hazard. Content of the Utility Model

[0004] In order to solve the problems involved in the background technique, the utility model provides an energy-saving, sealed and highly efficient scale-removing circulating cooling water electrochemical device for the treatment of circulating cooling water.

[0005] The technical solution adopted by the utility model is:

[0006] An energy-saving closed electrochemical device for treating circulating cooling water, wherein an integrated multi-slot plate-like scraper device for removing scale on the surface of a cathode has an integrated multi-slot plate-like structure, and the integrated multi-slot plate-like scraper device is arranged in a water tank of the electrochemical device, wherein the slots correspond to the cathodes one by one, and each cathode passes through a corresponding slot; the integrated multi-slot plate-like scraper device can not only significantly improve the mechanical strength, but also has a mutual support effect with the cathode and is not easy to deform, so that the net spacing between adjacent cathodes and anodes can be shortened to a minimum of about 5mm, and the generally preferred net spacing is 5-20mm, which significantly reduces the ohmic voltage drop and energy consumption, and greatly reduces the size of the electrochemical device; during operation, the lower surface of the integrated multi-slot plate-like scraper device is located below the water surface of the main water tank of the electrochemical device, which can effectively seal the water tank, prevent explosive or harmful substances such as hydrogen, oxygen and chlorine generated on the cathode and anode from being emitted around the water tank, and significantly improve the safety of operation.

[0007] The integrated multi-slit plate-shaped scraper device can be a single metal plate with multiple slits, or can be formed by closely splicing several metal plates with multiple slits; the cross section of the slit adopts a structural design of being wide at the top and narrow at the bottom, which is conducive to guiding the cathode through the slit during installation and reducing friction resistance during descaling.

[0008] The bottom width of the gap is greater than the cathode thickness by 0.05 mm to 0.5 mm; the cathode passes through the gap during the rising process to achieve surface descaling.

[0009] The integrated multi-slot plate-like scraper device is horizontally fixed in the water tank in a detachable manner and maintains a good seal with the inner wall of the water tank; the lower surface of the integrated multi-slot plate-like scraper device is covered with insulating material, and the appropriate distance from the upper end of the anode is 10-20 cm, so that it can be ensured that there is basically no current passing through the lower surface of the integrated multi-slot plate-like scraper device, and scale cannot accumulate on the lower surface. Even if a small amount of scale is deposited, it is easy to fall off automatically through the impact of hydrogen and oxygen bubbles generated during the treatment process or through the mechanical vibration generated during the scraping process of the cathode; the upper surface of the integrated multi-slot plate-like scraper device is appropriately 5-10 cm away from the top of the water tank.

[0010] A flushing device is provided above the integrated multi-slot plate-like scraper device. The flushing device automatically sprays water during the scraping process, which can effectively remove residual scale on the cathode and the integrated multi-slot plate-like scraper device, avoid the formation of hard scale, and improve the descaling stability of the integrated multi-slot plate-like scraper device.

[0011] The cathode is fixed to a cathode frame made of metal by bolts, and a good electrical connection is maintained between the cathode and the cathode frame;

[0012] The cathode rack is connected to a lifting device, and the lifting device can drive the cathode rack to move up and down with the cathode;

[0013] The water tank is provided with an electrical contact. During the treatment process, due to the dual effects of the gravity of the cathode and the cathode rack and the external pressure of the lifting device, close contact is maintained between the cathode rack and the electrical contact, thereby achieving good electrical connection between the cathode and the electrical contact;

[0014] The electrochemistry device is equipped with a control system. During the treatment process, the control system will continuously monitor the potential difference between the cathode rack and the electrical contact. When the measured potential difference exceeds a preset threshold, it indicates that the contact between the cathode rack and the electrical contact is poor, which is likely to cause excessive heating. At this time, the control system will automatically cut off the DC power supply to ensure the safe operation of the electrochemistry device;

[0015] When the water tank is made of a non-metallic material, in this case, the electrical contact is directly connected to the negative pole of the DC power supply; when the water tank is made of a metallic material, in this case, the electrical contact is directly connected to the negative pole of the DC power supply, or first electrically connected to the outer wall of the water tank, and then the outer wall of the water tank is electrically connected to the negative pole of the DC power supply to save electrical connection materials.

[0016] The water tank is provided with a water inlet, a water outlet, a sludge discharge port, a partition board and support feet. Among them, the water inlet and the water outlet are arranged on the same side of the water tank, and the sludge discharge port is arranged on the other side of the water tank far from the water inlet and the water outlet;

[0017] The water inlet is used to introduce the water to be treated into the water tank;

[0018] The water outlet is used to discharge the treated water from the water tank;

[0019] The sludge discharge port is used to discharge the scale sludge from the water tank;

[0020] The partition board is used to ensure uniform drainage;

[0021] The support feet are used to raise the water tank, which is beneficial to discharging the scale sludge.

[0022] The upper area of the water tank is used for electrochemical treatment, and the lower area is used for sedimentation and collection of scale sludge;

[0023] The bottom plate of the water tank is installed with a downward slope towards the sludge discharge port to facilitate the discharge of scale sludge.

[0024] The anode is fixed inside the water tank through an insulating slot component and is connected to the positive pole of the DC power supply through a terminal that is insulated and sealed from the water tank; the anode and the cathode are arranged parallel to each other and alternately at equal distances.

[0025] The slot assembly is an insulating plate with multiple grooves. Two slot assemblies are respectively fixed to the inner wall of the water tank and the partition plate by fixing screws, and the anode is inserted and fixed in the corresponding groove.

[0026] The lifting device is driven by hydraulic pressure, pneumatic pressure or motor.

[0027] When the number of the lifting device is set to one, it can be fixed to the beam of the building above the water tank, or it can be fixed to the inverted U-shaped frame above the water tank, and the frame is fixed to the water tank;

[0028] When the number of the lifting devices is set to two, they are respectively fixed on both sides of the outside of the water tank.

[0029] The beneficial effects of the utility model are:

[0030] 1. The utility model can improve the overall mechanical strength of the scraper device by arranging an integrated multi-slot plate-shaped scraper device, and provide mutual support between the scraper device and the cathode, making it not easy to deform. This can greatly reduce the scraper gap spacing, so that the net spacing between adjacent cathodes and anodes can be shortened to a minimum of about 5 mm, significantly reducing the ohmic voltage drop and energy consumption, and greatly reducing the size of the electrochemical device.

[0031] 2. The utility model seals the water tank through an integrated multi-slot plate-shaped scraper device, which can prevent explosive or harmful substances such as hydrogen, oxygen and chlorine generated during operation from being emitted around the water tank, thereby significantly improving the safety of operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a top view of the utility model.

[0033] Figure 2 for Figure 1 Schematic diagram of the AA section structure.

[0034] Figure 3 for Figure 1 Schematic diagram of the BB cross-section structure.

[0035] In the figure: 1. water tank, 2. lifting device, 3. cathode rack, 4. cathode, 5. flushing device, 6. anode, 7. integrated multi-slot plate scraper device, 8. slot, 9. electrical contact, 10. mud outlet, 11. supporting foot, 12. water inlet, 13. water outlet, 14. slot assembly, 15. partition, 16. fixing screws. DETAILED DESCRIPTION

[0036] The utility model is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0037] like Figure 1 ,Figure 2 and Figure 3 As shown, the electrochemical device is mainly composed of a water tank 1, a lifting device 2, a cathode frame 3, a cathode 4, a flushing device 5, an anode 6, an integrated multi-slot plate-shaped scraper 7, an electrical contact 9, a slot assembly 14 and a partition 15.

[0038] like Figure 2 As shown, the integrated multi-slot plate-like scraper 7 for removing the scale layer on the surface of the cathode 4 is an integrated multi-slot plate-like structure, and the integrated multi-slot plate-like scraper 7 is arranged in the water tank 1 of the electrochemical device, and the slots 8 correspond to the cathodes 4 one by one, and each cathode 4 passes through a corresponding slot 8; the integrated multi-slot plate-like scraper 7 can not only significantly improve the mechanical strength, but also there is a mutual support between it and the cathode 4, and it is not easy to deform, so that the net spacing between adjacent cathodes 4 and anodes 6 can be shortened to about 5mm at a minimum, which significantly reduces the ohmic voltage drop and energy consumption, and greatly reduces the size of the electrochemical device; during operation, the lower surface of the integrated multi-slot plate-like scraper 7 is located below the water surface of the main water tank 1 of the electrochemical device, which can effectively seal the water tank 1, and prevent explosive or harmful substances such as hydrogen, oxygen and chlorine generated on the cathode 4 and the anode 6 from being emitted around the water tank 1, thereby significantly improving the safety of operation.

[0039] The integrated multi-slit plate-shaped scraper device 7 can be a single metal plate with multiple slits 8, or it can be formed by closely splicing several metal plates with multiple slits 8; the cross section of the slit 8 adopts a structure design that is wide at the top and narrow at the bottom, such as a trapezoidal structure that is wide at the top and narrow at the bottom. In this way, on the one hand, it is beneficial to guide the cathode 4 through the slit 8 during the installation process, and on the other hand, it is beneficial to reduce the friction resistance during the descaling process. The bottom width of the slit 8 is greater than the cathode thickness of 0.05mm-0.5mm; the cathode 4 passes through the slit 8 during the rising process to achieve surface descaling.

[0040] The integrated multi-slot plate-like scraper device 7 is horizontally fixed in the water tank 1 in a detachable manner and maintains a good seal with the inner wall of the water tank 1; the lower surface of the integrated multi-slot plate-like scraper device 7 is covered with insulating material, and the appropriate distance from the upper end of the anode 6 is 10-20 cm, which can ensure that there is basically no current passing through the lower surface of the integrated multi-slot plate-like scraper device 7, and scale cannot accumulate on the lower surface. Even if a small amount of scale is deposited, it is easy to fall off automatically during the treatment process through the impact of hydrogen and oxygen bubbles generated or through the mechanical vibration generated during the scraping process; the upper surface of the integrated multi-slot plate-like scraper device 7 is appropriately 5-10 cm away from the top of the water tank 1.

[0041] like Figure 1 and Figure 2As shown in the figure, above the integrated multi-slit plate-shaped scale scraping device 7, there is a flushing device 5. The flushing device 5 automatically sprays water during the scale scraping process, which can effectively remove the residual scale on the cathode 4 and the integrated multi-slit plate-shaped scale scraping device 7, avoid the generation of hard scale, and improve the scale removal stability of the integrated multi-slit plate-shaped scale scraping device 7.

[0042] The cathode 4 is fixed under the cathode frame 3 made of metal by bolts, and there is a good electrical connection between the cathode 4 and the cathode frame 3;

[0043] The cathode frame 3 is connected to the lifting device 2, and the lifting device 2 can drive the cathode frame 3 and the cathode 4 to lift;

[0044] The water tank 1 is provided with an electrical contact 9. During the treatment process, under the dual action of the gravity of the cathode 4 and the cathode frame 3 and the external pressure of the lifting device 2, the cathode frame 3 and the electrical contact 9 are kept in close contact, so as to achieve a good electrical connection between the cathode 4 and the electrical contact 9;

[0045] The electrochemical device is equipped with a control system. During the treatment process, the control system will continuously monitor the potential difference between the cathode frame 3 and the electrical contact 9. When the measured potential difference exceeds the allowable threshold, it indicates that the contact between the cathode frame 3 and the electrical contact 9 is poor and is likely to cause excessive heating. At this time, the control system will automatically cut off the DC power supply to ensure the safe operation of the electrochemical device;

[0046] The water tank 1 can be made of non-metallic material. In this case, the electrical contact 9 is directly connected to the negative pole of the DC power supply; the water tank 1 can also be made of metal material. In this case, the electrical contact 9 can be directly connected to the negative pole of the DC power supply, or it can be first electrically connected to the outer wall of the water tank 1, and then the outer wall of the water tank 1 is electrically connected to the negative pole of the DC power supply to save electrical connection materials.

[0047] As Figure 3 shown in the figure, the water tank 1 is provided with a water inlet 12, a water outlet 13, a sludge discharge port 10, a partition 15 and support feet 11. Among them, the water inlet 12 and the water outlet 13 are arranged on the same side of the water tank 1, and the sludge discharge port 10 is arranged on the other side of the water tank 1 far from the water inlet 12 and the water outlet 13;

[0048] The water inlet 12 is used to introduce the water to be treated into the water tank 1;

[0049] The water outlet 13 is used to discharge the treated water from the water tank 1;

[0050] The sludge discharge port 10 is used to discharge the scale sludge from the water tank 1;

[0051] The partition 15 is used to ensure uniform drainage;

[0052] The support feet 11 are used to raise the water tank 1 to facilitate the discharge of scale sludge.

[0053] The upper region of the water tank 1 is used for electrochemical treatment, and the lower region is used for sedimentation and collection of scale sludge;

[0054] The bottom plate of the water tank 1 is installed with a downward slope towards the sludge discharge port 10 to facilitate the discharge of scale sludge.

[0055] The anode 6 is fixed inside the water tank 1 through the insulating slot component 14 and is connected to the positive pole of the DC power supply through a terminal block that is insulated and sealed from the water tank 1; the anode 6 and the cathode 4 are arranged parallel to each other and alternately at equal distances.

[0056] The slot component 14 is an insulating plate with multiple grooves. Two slot components 14 are respectively fixed to the inner wall of the water tank 1 and the partition 15 through fixing screws 16, and the anode 6 is inserted and fixed in the grooves of the slot component 14.

[0057] The lifting device 2 is hydraulically driven.

[0058] There is only one lifting device 2, which can be fixed on the cross beam of the building above the water tank 1, or can be fixed on the inverted U-shaped frame above the water tank 1, and the frame is fixed on the water tank 1. The single-drive lifting control mode is more helpful for the vertical lifting of the cathode 4 without deviation, avoiding the cathode 4 from tilting and scratching the anode 6 during the lifting process, resulting in damage to the expensive anode 6 (the anode cost accounts for about 70% of the total cost of the electrochemical equipment).

[0059] When the utility model operates, the circulating cooling water enters the water tank 1 through the water inlet 12 for electrochemical treatment:

[0060] The cathode 4 undergoes electrochemical reactions as shown in reaction formula (1) and reaction formula (2):

[0061] O2 + 2H2O + 4e - → 4OH - (1)

[0062] 2H2O + 2e - → 2OH - + H2 (2)

[0063] According to reaction formula (1) and reaction formula (2), a strong alkaline environment is generated near the cathode 4, and HCO3 in the water - is converted into CO3 2- , as shown in reaction formula (3), Ca 2+ / Mg 2+ migrate to the surface of the cathode 4 under the combined action of mass transfer process and electric field migration, and react with CO3 2- and OH - respectively to form precipitates, achieving the effect of removing hardness and alkalinity in the water. The reactions are shown in reaction formula (4) and reaction formula (5):

[0064] HCO3 - + OH - → CO3 2- + H2O (3)

[0065] Ca 2 + + CO3 2- → CaCO3↓ (4)

[0066] Mg 2 + + 2OH - → Mg (OH)2↓ (5)

[0067] The anode 6 generates strong oxides to achieve the effect of sterilization and algaecide, as shown in Reaction Formula (6) to Reaction Formula (11):

[0068] H2O → ·OH + H + +e - (6)

[0069] ·OH → 1 / 2 O2↑ + H + +e - (7)

[0070] 2Cl - →Cl2↑ + 2e - (8)

[0071] Cl2 + H2O → Cl - +ClO - +H + (9)

[0072] R + ·OH / ClO - →CO2↑ + H2O (10)

[0073] Bacteria and algae + ·OH / ClO - →Death / inactivation (11)

[0074] The water treated electrochemically is discharged to the circulation pool through the water outlet 13; when the scale sludge on the surface of the cathode 4 accumulates to a predetermined thickness, the electrochemical treatment is paused, and then the scale scraping is started. The cathode 4 rises driven by the lifting device 2. At the same time, the flushing device 5 sprays water to flush the integrated multi-slit plate-shaped scale scraping device 7 and the cathode 4, and efficient descaling of the surface of the cathode 4 is achieved under the dual action of mechanical scraping and water flushing; the scale sludge entrained with the flushing water is collected at the bottom of the water tank 1; when the lower edge of the cathode 4 rises to the lower surface of the slit 8 for scale scraping, the scale scraping is completed, and the cathode 4 automatically returns to the initial position driven by the lifting device 2, and the scale sludge precipitated to the bottom of the water tank 1 is discharged through the sludge outlet 10. The above operation process is repeated and carried out automatically in a cycle.

[0075] The circulating water is treated by using the device of the present utility model and a conventional device respectively, and a comparative test is carried out. The former uses the integrated multi-gap plate-shaped scale scraping device 7, and the net distance between the adjacent cathodes 4 and anodes 6 is only 8 mm; the latter uses an ordinary scraper, and due to the limitation of the scraper size, the net distance between the adjacent cathodes and anodes is 30 mm. During the test, the water quality, temperature, plate area, treatment flow rate, treatment time and operating current are the same. The specific comparative test data are shown in Table 1.

[0076] Table 1 Influence of different scale scraping devices on the operation of electrochemical equipment

[0077]

[0078]

[0079] As can be seen from Table 1, the scale removal of the cathode 4 using the device of the present utility model is more efficient. The net distance between the adjacent cathodes 4 and anodes 6 can be set shorter, the average operating voltage can be reduced from 20 V to 8 V, and the energy consumption can be reduced from 30 kWh to 12 kWh. In addition, the volume of the device of the present utility model can be reduced by nearly 50%.

[0080] Finally, it should be noted that the above embodiments and descriptions are only used to illustrate the technical solutions of the present utility model and are not intended to limit them. Those of ordinary skill in the art should understand that the technical solutions of the present utility model can be modified or equivalently replaced. Without departing from the spirit and scope of the disclosure of the technical solutions of the present utility model, they should all be covered by the protection scope of the claims of the present utility model.

Claims

1. An energy-saving closed electrochemical device for treating circulating cooling water, characterized in that: The integrated multi-slot plate-like scraper device for removing scale on the cathode surface is an integrated multi-slot plate-like structure, wherein the slots correspond to the cathodes one by one, and each cathode passes through a corresponding slot; the net spacing between adjacent cathodes and anodes is shortened to a minimum of about 5 mm; during operation, the lower surface of the integrated multi-slot plate-like scraper device is located below the water surface of the water tank of the electrochemical device, thereby effectively sealing the water tank.

2. An energy-saving closed electrochemical device for treating circulating cooling water according to claim 1, characterized in that: The integrated multi-slit plate-shaped scraper device is a single metal plate with multiple slits, or is formed by closely splicing several metal plates with multiple slits; the vertical cross-section of the slit is wide at the top and narrow at the bottom, and the bottom width of the slit is 0.05mm-0.5mm larger than the cathode thickness; the cathode passes through the slit during the rising process to achieve descaling of the cathode surface.

3. The energy-saving closed electrochemical device for treating circulating cooling water according to claim 1, characterized in that: The integrated multi-slot plate-shaped scraper device is horizontally fixed in the water tank in a detachable manner and maintains a good seal with the inner wall of the water tank; the lower surface of the integrated multi-slot plate-shaped scraper device is covered with insulating material, and the distance from the upper end of the anode is 10-20 cm; the distance between the upper surface of the integrated multi-slot plate-shaped scraper device and the top of the water tank is 5-10 cm.

4. An energy-saving closed electrochemical device for treating circulating cooling water according to any one of claims 1 to 3, characterized in that: A flushing device is provided above the integrated multi-slot plate-shaped scraping device, and the flushing device is used for automatically spraying water during the scraping process of the cathode.

5. The energy-saving closed electrochemical device for treating circulating cooling water according to claim 1, characterized in that: The cathode is fixed under a cathode frame made of metal, and the cathode and the cathode frame are electrically connected; The cathode frame is connected to a lifting device, and the lifting device drives the cathode frame and the cathode to rise and fall; The water tank is provided with an electrical contact, and during the treatment process, the cathode frame and the electrical contact are kept in close contact by the dual action of the gravity of the cathode and the cathode frame and the external pressure of the lifting device, thereby achieving electrical connection between the cathode and the electrical contact; The electrochemical device is equipped with a control system, which is used to continuously monitor the potential difference between the cathode frame and the electrical contact during the treatment process, and when the measured potential difference exceeds a preset threshold, the control system will automatically cut off the DC power supply; When the water tank is made of non-metallic material, the electrical contact is directly connected to the negative pole of the DC power supply; when the water tank is made of metal material, the electrical contact is directly connected to the negative pole of the DC power supply, or is first electrically connected to the outer wall of the water tank, and then the outer wall of the water tank is electrically connected to the negative pole of the DC power supply.

6. The energy-saving closed electrochemical device for treating circulating cooling water according to claim 1, characterized in that: The anode is fixed inside the water tank through an insulating slot assembly, and the anode is connected to the positive pole of a DC power supply through a terminal block that is insulated and sealed from the water tank; the anode and cathode are parallel to each other and arranged alternately and equidistantly; the slot assembly is an insulating plate with multiple grooves, and each anode is inserted and fixed in a corresponding groove.

7. The energy-saving closed electrochemical device for treating circulating cooling water according to claim 1, characterized in that: The water tank is provided with a water inlet, a water outlet, a mud outlet, a partition and a support leg, wherein the water inlet and the water outlet are arranged on the same side of the water tank, and the mud outlet is arranged on the other side of the water tank away from the water inlet and the water outlet; The water inlet is used to introduce the water to be treated into the water tank; The water outlet is used to discharge the treated water out of the water tank; The mud discharge port is used to discharge the sludge out of the water tank; The baffles are used to ensure uniform drainage; The support legs are used to raise the water tank; The upper area of ​​the water tank is used for electrochemical treatment, and the lower area is used for sedimentation and collection of sludge; The bottom plate of the water tank is installed tilted downward toward the mud discharge port.

8. The energy-saving closed electrochemical device for treating circulating cooling water according to claim 5, characterized in that: The lifting device is driven by hydraulic pressure, pneumatic pressure or motor.

9. An energy-saving closed electrochemical device for treating circulating cooling water according to claim 5 or 8, characterized in that: When the number of the lifting devices is set to one, the lifting device is fixed to a beam of a building above the water tank, or to an inverted U-shaped frame above the water tank, and the frame is fixed to the water tank; When the number of the lifting devices is set to two, the two lifting devices are respectively fixed on two sides of the outside of the water tank.

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