Anti-scaling electromagnetic device and control method therefor, and heat exchange apparatus

Abstract

An anti-scaling electromagnetic device and a control method therefor, and a heat exchange apparatus, which relate to the technical field of pipe descaling. The anti-scaling electromagnetic device comprises: a water tank having a water inlet and a water outlet; and a pipe provided in the water tank, wherein the parts in the water tank located on the inner and outer sides of the pipe are in communication with each other, coils are provided on the pipe, the coils are connected in series to a power supply to form an anti-scaling circuit, and a switch for controlling the on / off of the anti-scaling circuit is provided on the anti-scaling circuit. In the anti-scaling electromagnetic device, the coils on the pipe are immersed in water in the water tank, magnetic fields are generated after the coils are energized, and an aqueous solution throughout the water tank is subjected to the action of electromagnetic fields to generate variable-frequency resonance fields, thereby achieving descaling and anti-scaling; and since the magnetic fields can be formed on both the inner and outer sides of the pipe connected to the coils, the magnetic fields on both the inner and outer sides of the pipe can be applied to anti-scaling operations, and thus the magnetic fields inside and outside the coils are utilized to the maximum extent, the full use of the magnetic fields can be ensured and the anti-scaling space can be expanded, thereby improving anti-scaling efficiency.

Description

A scale-inhibiting electromagnetic device and its control method, and a heat exchange equipment.

[0001] This application claims priority to Chinese Patent Application No. 202411999104.8, filed on December 31, 2024, entitled "An Electromagnetic Device for Scale Inhibition and Its Control Method and Heat Exchange Equipment", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This invention relates to the field of pipeline descaling technology, and in particular to a scale-inhibiting electromagnetic device and its control method, as well as a heat exchange device. Background Technology

[0003] Scale buildup is a common phenomenon in production and daily life. Pipelines and heat exchange equipment in many industrial sectors, such as energy, chemical, and petroleum, are affected by scale problems to varying degrees. As the system operates for longer periods, scale gradually accumulates on the walls of heat exchangers and pipes, increasing the heat transfer resistance of the heat exchanger and thus affecting its heat transfer efficiency, leading to energy waste.

[0004] One current method for descaling is physical scale prevention, which uses physical instruments and equipment to inhibit scale formation. Electromagnetic descaling is the most commonly used physical scale prevention method.

[0005] In the process of realizing this invention, the inventors discovered that the prior art has at least the following problems: In a current scale-inhibiting electromagnetic device, the coil is sleeved on the outside of the pipe body, and water is circulated inside the pipe body to inhibit and remove scale. Due to the limitation of the water storage space, the scale inhibition efficiency is low.

[0006] Therefore, how to improve scale inhibition efficiency is a technical problem that needs to be solved by those skilled in the art. Summary of the Invention

[0007] In view of this, the purpose of the present invention is to provide a scale inhibition electromagnetic device and its control method, as well as a heat exchange device, which can improve scale inhibition efficiency.

[0008] To achieve the above objectives, the present invention provides the following technical solution:

[0009] A scale-inhibiting electromagnetic device includes: a water tank having an inlet and an outlet; a pipe disposed in the water tank, wherein the inner and outer sides of the pipe in the water tank are connected; a coil is disposed on the pipe, the coil being connected in series with a power source to form a scale-inhibiting circuit, and a switch controlling its on / off state is provided on the scale-inhibiting circuit.

[0010] Preferably, the tube body includes an inner cylinder and an outer cylinder sleeved outside the inner cylinder, with an interlayer formed between the inner cylinder and the outer cylinder, and the interlayer is sealed at both ends in the axial direction, and the coil is located in the interlayer.

[0011] Preferably, the tube is placed vertically in the water tank, and the wire used to electrically connect the coil to the power source in the scale inhibition circuit is led out from the top of the tube.

[0012] Preferably, the tube body includes an annular top cover, the top end of the interlayer is sealed by the top cover, and the top ends of the inner cylinder and the outer cylinder extend into the top cover.

[0013] Preferably, the water inlet of the water tank is located at the lower end of the water tank, and the water inlet is located radially inside the inner cylinder, while the water outlet of the water tank is located on the side of the water tank.

[0014] Preferably, there are multiple coils, each coil forming a separate scale-inhibiting circuit with the power supply, and each scale-inhibiting circuit is provided with a switch.

[0015] Preferably, the coils are arranged sequentially from bottom to top on the tube.

[0016] Preferably, the system further includes a controller and a flow rate sensor disposed in the water tank for detecting the water flow rate in the water tank; the controller is used to control the opening and closing of the switch based on the water flow rate detected by the flow rate sensor.

[0017] A control method for a scale-inhibiting electromagnetic device, applied to the scale-inhibiting electromagnetic device as described above; the control method includes: detecting the water flow velocity in the water tank; and determining the on / off state of the switch based on the water flow velocity.

[0018] A heat exchange device includes the scale-inhibiting electromagnetic device described above.

[0019] Compared with the prior art, this application has at least the following beneficial effects:

[0020] The scale-inhibiting electromagnetic device provided by the present invention includes: a water tank having an inlet and an outlet; a pipe body disposed in the water tank, wherein the inner and outer sides of the pipe body in the water tank are connected; a coil is disposed on the pipe body, the coil being connected in series with a power source to form a scale-inhibiting circuit, and a switch controlling its on / off state is provided on the scale-inhibiting circuit.

[0021] Compared with the prior art, this application has at least the following beneficial effects:

[0022] In this type of scale-inhibiting electromagnetic device, the coil on the tube is immersed in the water in the tank. After the coil is turned on, a magnetic field is generated. The aqueous solution in various parts of the tank is affected by the electromagnetic field, generating a variable frequency resonant field. This causes a large amount of active oxygen in the aqueous solution to be activated, which has the functions of sterilizing and inhibiting bacteria and algae, thus achieving scale removal and scale inhibition. Furthermore, since magnetic fields can be formed on both the inner and outer sides of the tube connecting the coil, the magnetic fields on both sides of the tube can be used in the scale inhibition operation, maximizing the utilization of the magnetic fields inside and outside the coil. This ensures the full application of the magnetic field and expands the scale inhibition space, thereby improving the scale inhibition efficiency. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0024] Figure 1 is a schematic diagram of a specific embodiment of the scale-inhibiting electromagnetic device provided by the present invention.

[0025] Figure label:

[0026] Controller 1;

[0027] Switch 2;

[0028] Coil 3;

[0029] Power supply 4;

[0030] tube body 5;

[0031] Flow rate sensor 6;

[0032] Water tank 7. Detailed Implementation

[0033] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] The core of this invention is to provide a scale-inhibiting electromagnetic device and its control method, as well as a heat exchange device, which can improve scale inhibition efficiency.

[0035] The first specific embodiment of the scale-inhibiting electromagnetic device provided by the present invention is applied to a heat exchanger. Please refer to Figure 1. It includes a water tank 7, a pipe body 5, a coil 3, a switch 2, and a power supply 4.

[0036] Water tank 7 has an inlet and an outlet. Water enters water tank 7 through the inlet and is discharged from the outlet after scale inhibition and removal. The water tank can be a traditional large-capacity circulating water tank. The water in water tank 7 can circulate, for example, by adding a circulating pump to drive the water circulation to inhibit scale. Water tank 7 can be a fully enclosed structure or a semi-enclosed structure with openings.

[0037] The pipe body 5 is disposed in the water tank 7, and the portions of the pipe body 5 located on the inner and outer sides of the water tank 7 are connected. The inner and outer sides of the pipe body 5 refer to the portion between the inner side of the inner circumferential surface and the outer side of the outer circumferential surface. Specifically, the pipe body 5 is a straight pipe, or more specifically, a circular pipe. The pipe body 5 extends axially and is an axially continuous channel structure. In other embodiments, the pipe body 5 may also be open at only one end axially, or the pipe body 5 may be an arc-shaped pipe or a pipe of other shapes.

[0038] A coil 3 is provided on the pipe body 5. The coil 3 is connected in series with the power supply 4 to form a scale-inhibiting circuit, and a switch 2 is provided on the scale-inhibiting circuit to control its on and off. When multiple coils 3 are provided, the number of coils 3 and switches 2 are equal and corresponding one-to-one, and they are located in different scale-inhibiting circuits.

[0039] In this circuit, power supply 4 is an AC power supply, specifically 220V AC. In each scale inhibition circuit, the AC power supply, switch 2, and the corresponding coil 3 are connected in series. When switch 2 is closed, the corresponding scale inhibition circuit forms a loop, coil 3 conducts, and the AC power supply provides AC current to the corresponding coil 3, causing coil 3 to generate an alternating magnetic field. Switch 2 can be driven by a small-level digital signal and can also be loaded with an excitation signal.

[0040] In this type of scale-inhibiting electromagnetic device, the coil 3 on the tube 5 is immersed in the water in the water tank 7. After the coil 3 is turned on, a magnetic field is generated. The aqueous solution in the water tank 7 is affected by the electromagnetic field, generating a frequency-resonant field. This causes a large amount of active oxygen in the aqueous solution to be activated, which has the functions of sterilization, inhibition of bacteria and algae, and scale removal and inhibition. Since magnetic fields can be formed on both the inner and outer sides of the tube 5 connected to the coil 3, the magnetic fields on both the inner and outer sides of the tube 5 can be used in the scale inhibition operation, maximizing the use of the magnetic fields inside and outside the coil 3. This ensures the full application of the magnetic field and expands the scale inhibition space, thereby improving the scale inhibition efficiency.

[0041] Furthermore, the tube body 5 includes an inner cylinder and an outer cylinder sleeved outside the inner cylinder, forming a sandwich between the inner and outer cylinders. The sandwich is sealed at both ends in the axial direction, forming a sealed waterproof cavity. The coil 3 is located within this sandwich, specifically within the waterproof cavity, and is tightly wound around the inner cylinder. After the coil 3 is assembled with the tube body 5, the coil 3 is waterproofed, ensuring the safety of equipment operation. Of course, in other embodiments, waterproofing of the coil 3 can also be achieved by providing a waterproof coating.

[0042] Further, as shown in Figure 1, the tube body 5 is placed vertically in the water tank 7, and the wire used to electrically connect the coil 3 to the power supply 4 in the scale inhibition circuit is led out through the top of the tube body 5. The bottom end of the tube body 5 can be fitted against the bottom wall of the water tank 7. At the same time, the power supply 4 and the switch 2 are externally located in the water tank 7, which facilitates equipment maintenance while being waterproof. In other embodiments, the power supply 4 and the switch 2 can be housed in a waterproof box and then internally housed in the water tank 7.

[0043] This orientation of the pipe body 5 facilitates the routing of electrical wires and reduces the impact of water in the water tank 7 on the wires, thereby improving the safety of equipment operation. At the outlet of the electrical wire on the pipe body 5, the wire and outlet are sealed, specifically with a sealing ring or sealant.

[0044] Furthermore, the tube body 5 includes an annular top cover, the top of the interlayer is sealed by the top cover, and the top of the inner cylinder and the top of the outer cylinder extend into the top cover to facilitate the installation of the wires. Specifically, after the wires are assembled with the top cover, the top cover is then placed on the interlayer between the inner cylinder and the outer cylinder.

[0045] The top cover can be made of rigid material, which can serve not only as a seal but also as a support.

[0046] In addition, the other end between the inner cylinder and the outer cylinder in the axial direction, that is, the bottom end of the interlayer in this embodiment, can be sealed by an annular sealing layer. Specifically, it can be made of the same material as the inner cylinder and the outer cylinder. During processing, the inner cylinder, the sealing layer and the outer cylinder can be integrally formed, or they can be fixedly connected by bonding or other methods.

[0047] In addition, the material of the tube body 5 should be a chemically stable material that will not react chemically with the medium in the water tank 7, and should be heat-resistant, for example, with a temperature resistance of not less than 100℃; at the same time, the tube body 5 should be a material through which magnetic fields can pass, and the magnetic field generated by the coil 3 inside the tube body 5 can reach the inner side of the inner circumference and the outer side of the outer circumference, specifically covering the entire space inside the water tank 7.

[0048] Furthermore, the water inlet of the water tank 7 is located at the lower end of the water tank 7, and the water inlet is located on the inner side of the inner cylinder in the radial direction, while the water outlet of the water tank 7 is located on the side of the water tank 7.

[0049] At this time, after the water enters the water tank 7, since the inner cylinder has an axial through hole structure, it can first enter the inner side of the inner cylinder from below, and then move from the top of the pipe body 5 to the space located outside the outer cylinder in the water tank 7, and then flow out of the outlet of the water tank 7, ensuring the fluidity of the water in the space inside the inner cylinder, so that the water in this space that has been treated with anti-scaling can flow out of the water tank 7 smoothly.

[0050] Of course, in other embodiments, fluid passages can also be provided on the tube body 5, with the two ends of the passage wall respectively sealing and connecting the inner cylinder and the outer cylinder, increasing the smoothness of fluid flow on both sides of the tube body 5, while avoiding affecting the sealing performance of the interlayer.

[0051] Furthermore, there are multiple coils 3, each coil 3 forming a separate scale inhibition circuit with the power supply 4, and each scale inhibition circuit is equipped with a switch 2. Each coil 3 can be turned on as needed, which can improve the flexibility of scale inhibition.

[0052] To facilitate assembly or based on the requirements of the alternating magnetic field, each coil 3 is arranged sequentially from bottom to top on the tube body 5, which also makes it convenient to number the coils 3 and control the conduction of each coil 3 in sequence.

[0053] In addition, each coil 3 is tightly wound around the outside of the inner cylinder. The number of coils 3 is positively correlated with the axial length of its tube 5. The longer the tube, the more coils 3 will be, and the shorter the tube, the fewer coils 3 will be.

[0054] Each coil 3 can cover the entire outer circumference of the inner cylinder along the axial direction. Specifically, the number of coils 3 can be selected according to the axial length of the inner cylinder and the width of the coils 3. Along the axial direction, each coil 3 is wound sequentially around the outer circumference of the inner cylinder. In this embodiment, there can be 3 coils 3. In other embodiments, depending on the axial length of the inner cylinder and the length of the coils 3, there can also be 1, 4, or other numbers of coils 3.

[0055] Furthermore, the scale-inhibiting electromagnetic device also includes a controller 1 and a flow rate sensor 6 installed in the water tank 7 for detecting the water flow velocity in the water tank 7. The controller 1 is electrically connected to the switch 2 and the flow rate sensor 6. The flow rate sensor 6 serves as the input terminal of the controller 1. The controller 1 controls the opening and closing of the switch 2 based on the water flow velocity detected by the flow rate sensor 6, including the opening and closing time and duration, thereby adjusting the conduction status and duration of the coil 3. The controller 1 is specifically a control chip. The flow rate sensor 6 is located at a preset position in the water tank 7, specifically inside or outside the pipe body 5.

[0056] At this time, the flow rate sensor 6 is used to detect the water flow rate in the water tank 7, and each switch 2 is used to control the conduction and cutoff of the corresponding coil 3. The controller 1 calculates the total conduction time of the coil 3 according to the water flow rate signal of the flow rate sensor 6, and controls multiple switches 2 to periodically alternately close in a preset order according to the total conduction time, so that the coil 3 generates an alternating magnetic field when the corresponding switch 2 is closed.

[0057] The signal measured by the flow rate sensor 6 controls the switch 2 to determine whether the coil 3 is turned on and for how long. The control is simple, the energization method of the coil 3 is changed, and the magnetic fields inside and outside the coil 3 are utilized to the maximum extent, which improves the scale inhibition efficiency. In addition, the investment cost is low, the operating efficiency is high, the installation is simple, and the maintenance is convenient.

[0058] The scale inhibition electromagnetic device in this embodiment includes the following scale inhibition process:

[0059] Controller 1 energizes control coil 3. When coil 3 is conducting, an alternating electromagnetic field is generated inside and outside the pipe 5 within the water tank 7. This alternating electromagnetic field resonates with water molecules, causing hydrogen bonds to break and water molecule clusters to become individual polar water molecules. This increases the water's activation and solubility for scale. Extremely small water molecules can penetrate, surround, loosen, dissolve, and remove old scale from the pipes. Simultaneously, calcium and carbonate ions floating in the water collide to form special aragonite calcium carbonate bodies. These bodies have no surface charge and therefore cannot be adsorbed onto the pipe 5 or the water tank 7, thus achieving the purpose of scale removal and prevention. The aqueous solution in the water tank 7 and the circulating pipes is affected by the electromagnetic field, generating a variable frequency resonant field that activates a large amount of active oxygen in the aqueous solution, also possessing bactericidal, antibacterial, and algae-killing functions.

[0060] In addition to the aforementioned scale-inhibiting electromagnetic device, the present invention also provides a control method for the scale-inhibiting electromagnetic device, specifically capable of controlling the scale-inhibiting electromagnetic device in the above embodiments. This control method can be executed by the controller 1 in the scale-inhibiting electromagnetic device.

[0061] The control method includes:

[0062] S1: Detect the water flow rate in water tank 7.

[0063] The water flow speed is detected by the flow rate sensor 6 in the water tank 7.

[0064] S2: Determine whether switch 2 is on or off based on the water flow speed.

[0065] Specifically, if there are multiple coils 3, then in S2, the on / off state of switch 2 is determined based on the water flow velocity, specifically including:

[0066] S21: According to the water flow speed, control each coil 3 to conduct in sequence according to a preset order, wherein one coil 3 is conducted at a time.

[0067] Three coils are set up, from bottom to top as the first coil, the second coil, and the third coil.

[0068] During the process of controlling each coil 3 to conduct in sequence according to the preset order, the preset order can be calibrated according to the actual situation. For example, it can be sorted from top to bottom, or from bottom to top, or it can be not in the top-bottom order. The preset order only needs to meet the requirement that there are no repetitions.

[0069] Specifically, to facilitate determining the conduction sequence of coils 3, there are N coils 3, where N is a positive integer greater than 1. Each coil 3 is numbered from 1 to N according to a preset order, designated as the i-th coil, where i is a positive integer, and 1 ≤ i ≤ N, with i taking values ​​between 1 and N. Furthermore, switch 2 and coils 3 in the same scale-inhibiting circuit are numbered in the same way; that is, the i-th coil is controlled by the i-th switch and has the same value as i.

[0070] Specifically, each coil 3 can be periodically switched on according to its number. When controlling the switching on and off of coil 3, values ​​from 1 to N can be selected, and the corresponding coil 3 can be switched on sequentially according to its number, with only one coil 3 switched on at a time. The number of coils 3 switched on can be determined based on the calculated total switching time. If the total switching time is not reached after all coils 3 have been switched on once, the switching can be repeated starting from coil 1.

[0071] Specifically, the conduction time of a single coil 3 can be the same each time, and the conduction interval between adjacent coils 3 can also be the same. The conduction time and the interval can also be equal. During the interval, each coil 3 is in an off state.

[0072] Specifically, the numbering of each coil 3 can be adjusted each time it is used, depending on actual needs. Specifically, the coils can be numbered before each startup, cleared when the machine is turned off, and renumbered for the next use.

[0073] Specifically, the total conduction time of coil 3 is calculated using the following formula:

[0074] Where T represents the conduction time of coil 3, n represents the total number of segments of coil 3, L represents the sum of the widths of n coils 3 in meters, and V represents the water flow velocity in meters per second.

[0075] The control method in this embodiment calculates the total conduction time of the coil based on the water flow velocity, and controls multiple switches to periodically and alternately close in a preset order according to the total conduction time. This causes the coil 3 to generate an alternating magnetic field when the corresponding switch 2 is closed, resulting in good scale inhibition. The signal measured by the flow velocity sensor controls the switch 2 to determine whether the coil 3 is conducting and the conduction time. The control is simple, changes the energization method of the coil 3, and improves the descaling efficiency. It has low investment cost, high operating efficiency, simple installation, and convenient maintenance. By using physical methods for scale inhibition and removal, it can effectively avoid the corrosive effect of chemical agents on the equipment, extend the service life of the equipment, reduce the intangible loss of fixed assets, and also protect the ecological environment.

[0076] In addition, the present invention provides a heat exchange device that applies the above-mentioned scale-inhibiting electromagnetic device and its control method, which can ensure scale removal efficiency.

[0077] It should be noted that when an element is referred to as "fixing" another element, it can be directly attached to the other element or there may be an intervening element. When an element is referred to as "connecting" another element, it can be directly connected to the other element or there may be an intervening element. Furthermore, in the description of this application, unless otherwise stated, "multiple," "multiple roots," and "multiple groups" mean two or more.

[0078] The terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated.

[0079] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0080] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0081] The scale-inhibiting electromagnetic device and its control method, as well as the heat exchange equipment provided by this invention, have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are merely for the purpose of helping to understand the method and core ideas of this invention. It should be noted that those skilled in the art can make various improvements and modifications to this invention without departing from its principles, and these improvements and modifications also fall within the protection scope of the claims of this invention.

Claims

1. A scale-inhibiting electromagnetic device, characterized in that, include: Water tank (7), the water tank (7) having an inlet and an outlet; A pipe (5) is provided in the water tank (7), and the inner and outer sides of the pipe (5) in the water tank (7) are connected. A coil (3) is provided on the pipe (5), and the coil (3) is connected in series with the power supply (4) to form a scale-inhibiting circuit. A switch (2) is provided on the scale-inhibiting circuit to control its on and off.

2. The scale-inhibiting electromagnetic device according to claim 1, characterized in that, The tube body (5) includes an inner cylinder and an outer cylinder sleeved outside the inner cylinder. An interlayer is formed between the inner cylinder and the outer cylinder, and the two ends of the interlayer are sealed in the axial direction. The coil (3) is located in the interlayer.

3. The scale-inhibiting electromagnetic device according to claim 2, characterized in that, The tube (5) is placed vertically in the water tank (7), and the wire used to electrically connect the coil (3) to the power source (4) in the scale inhibition circuit is led out from the top of the tube (5).

4. The scale-inhibiting electromagnetic device according to claim 3, characterized in that, The tube body (5) includes an annular top cover, the top end of the interlayer is sealed by the top cover, and the top ends of the inner cylinder and the outer cylinder extend into the top cover.

5. The scale-inhibiting electromagnetic device according to claim 3, characterized in that, The water inlet of the water tank (7) is located at the lower end of the water tank (7), and the water inlet is located radially inside the inner cylinder. The water outlet of the water tank (7) is located on the side of the water tank (7).

6. The scale-inhibiting electromagnetic device according to claim 3, characterized in that, There are multiple coils (3), and each coil (3) forms a separate scale-inhibiting circuit with the power supply (4). Each scale-inhibiting circuit is equipped with a switch (2).

7. The scale-inhibiting electromagnetic device according to claim 6, characterized in that, The coils (3) are arranged sequentially from bottom to top on the tube (5).

8. The scale-inhibiting electromagnetic device according to claim 7, characterized in that, It also includes a controller (1) and a flow rate sensor (6) disposed in the water tank (7) for detecting the water flow rate in the water tank (7); the controller (1) is used to control the opening and closing of the switch (2) according to the water flow rate detected by the flow rate sensor (6).

9. A control method for a scale-inhibiting electromagnetic device, characterized in that, Applied to the scale-inhibiting electromagnetic device according to any one of claims 1 to 8; The control method includes: Detect the water flow rate in the water tank (7); The on / off state of the switch (2) is determined based on the water flow velocity.

10. A heat exchange device, characterized in that, Includes the scale-inhibiting electromagnetic device as described in any one of claims 1 to 8.

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