Method and system for sterilizing industrial circulating water

Abstract

The application discloses an industrial circulating water sterilization method and system. The sterilization method comprises the following steps: A1, performing hydraulic cavitation treatment on a circulating water tank, destroying microbial cell walls by using a hydraulic cavitation mechanical action, and performing partial sterilization; A2, water treated by the hydraulic cavitation treatment is introduced into an ultraviolet sterilization device to perform deep sterilization; and A3, sterilized water is sprayed on a workpiece to be cleaned through a spraying pipeline, and the cleaned water enters the circulating water tank to perform the next cycle. The sterilization system comprises a circulating water tank, a spraying pipeline, an ultraviolet sterilization device, a liquid outlet and a liquid inlet, wherein the liquid inlet is connected with the circulating water tank, the liquid outlet is connected with the spraying pipeline, and a hydraulic cavitation module comprises a high-pressure pump and a hydraulic cavitation device which are connected in sequence. The application combines the hydraulic cavitation and ultraviolet light, optimizes the structure of a process flow, strengthens sterilization efficiency, and eliminates the aggregation of white flocculent polymers.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of industrial circulating water sterilization, in particular to the field of electrophoresis line circulating water sterilization. BACKGROUND

[0002] The main role of industrial circulating water is in washing and heat exchange. Through the purification treatment of the characteristics of industrial circulating water, the corresponding impurities can be removed, which can greatly improve the utilization efficiency of water and the efficiency of industrial production, and solve the problem of waste. Industrial circulating water system usually has conditions suitable for the growth of microorganisms, temperature 25-40℃, relatively mild pH value and a large amount of nutrients after water evaporation and concentration, which form a breeding ground for microorganism growth. Especially in the open circulating cooling water system, there is sufficient dissolved oxygen, which aggravates the growth of microorganisms.

[0003] In the field of automobile manufacturing, the bacterial content in the circulating water of the pretreatment line is generally greater than 10³CFU / mL (depending on the number of bacteria, the detection frequency is about 1 time / month), which will adsorb a large area of bacterial corpses on the vehicle body. These white flocculent substances are the corpses of bacteria. If not cleaned thoroughly, they will be brought into the electrophoresis tank with the workpiece to be electrophoresed. After electrophoresis and baking, hollow large particles will appear in the inner layer of the electrophoresis. This kind of hollow particles cannot be eliminated by surface polishing and must be polished by a polishing machine / small size sandpaper (usually 400#). Otherwise, after spraying the topcoat, a large number of hollow small pinholes will appear, causing the unqualified corrosion and appearance quality.

[0004] The bacterial content in the electrophoresis line is generally greater than 10 4 CFU / mL, which will affect the cleaning and anode system circulation (detection frequency 2-4 weeks / time). The bacteria cause the continuous decline of ultrafiltration flow. More and more white flocculent substances are found in the anode tank and anode flowmeter. The slow ultrafiltration circulation efficiency will affect the pH stability of the tank liquid in the electrophoresis tank body, and the MEQ value of the tank liquid fluctuates, the paint stability is poor, which will directly cause the roughness of the paint film, the increase of the film thickness, and even the whole tank electrophoresis paint and the anode system may be scrapped.

[0005] The technical problems to be solved at present are: ① removing the bacterial flora in the circulating water of the electrophoresis line and keeping a low number of bacteria; ② eliminating white flocculent substances and preventing the accumulation of flocculent substances in the circulating water.

[0006] The prior art uses ultrasonic cavitation to sterilize contaminated water. Ultrasonic sterilization technology mainly uses cavitation, mechanical effect and the like generated by ultrasonic waves to achieve sterilization and algae removal of circulating water. Factors affecting the sterilization effect of ultrasonic waves include: ① ultrasonic sterilization time. The sterilization effect is roughly proportional to the sterilization time, but further increasing the sterilization time tends to reach a stable value. Moreover, as the sterilization time increases, the water temperature in the process of sterilizing circulating water tends to increase. ② ultrasonic frequency. The higher the frequency of ultrasonic waves, the more obvious the cavitation effect, and the more obvious the destruction of bacteria and algae cells by ultrasonic waves. However, as the frequency increases, the propagation of sound waves decays faster. Therefore, ultrasonic waves have limitations in sterilizing circulating water and are not suitable for large-scale industrial applications.

[0007] Ultraviolet sterilization technology usually uses a transparent quartz sleeve with a UV light fixed at a corresponding position of a circulating water pipeline to emit ultraviolet light with sterilization effect, so as to achieve the purpose of sterilizing and removing algae from circulating water. The factors affecting the water treatment effect of the ultraviolet sterilization system mainly include the following two aspects: ① Circulating water transparency. Generally, the lower the penetration rate of ultraviolet light, the worse the sterilization and algae removal effect. When there are suspended solids in the circulating water, the suspended particles will absorb and disperse the energy of the ultraviolet light, and the bacteria and algae will be protected from the destruction of the ultraviolet light by hiding in the particles. ② Ultraviolet action time and effective intensity. In the actual process of ultraviolet sterilization of circulating water, if the water volume suddenly increases and the ultraviolet contact time is short, a stronger ultraviolet dose is required to achieve effective sterilization. Therefore, single ultraviolet sterilization technology also has limitations. SUMMARY

[0008] In order to solve the problem of sterilizing industrial circulating water, the present application provides an industrial circulating water sterilization method and a sterilization system. The water force cavitation-ultraviolet light combination is combined with the optimization of the process flow structure to strengthen the sterilization efficiency, eliminate the aggregation of white flocculent polymers, ensure the coating quality after electrophoresis of the workpiece, and maintain the cleanliness of the circulating water for a long time.

[0009] Based on the above problems, the present application is as follows:

[0010] The industrial circulating water sterilization method comprises the following steps:

[0011] A1. Water force cavitation treatment is performed on the water to be sterilized in the circulating water tank, and the water force cavitation mechanical action is used to destroy the cell wall of microorganisms to achieve partial sterilization;

[0012] A2. The water treated by water force cavitation is introduced into an ultraviolet sterilization device for deep sterilization;

[0013] A3. The sterilized water is sprayed on the workpiece to be cleaned through a spray pipeline, and the cleaned water enters the circulating water tank for the next cycle.

[0014] Further, the A1 step, the water to be sterilized in the circulating water tank is filtered by the pre-filter to remove the particulate impurities in the water, and then is pumped into the hydrodynamic cavitation device for hydrodynamic cavitation treatment.

[0015] Further, the A1 and A2 steps, the water to be sterilized in the circulating water tank is subjected to the circulating hydrodynamic cavitation treatment by the hydrodynamic cavitation device for several times or for several time periods; and the water subjected to the circulating hydrodynamic cavitation treatment is subjected to the ultraviolet sterilization treatment.

[0016] Alternatively, the circulating water is subjected to the circulating hydrodynamic cavitation treatment through the branch pipeline, and is subjected to the ultraviolet sterilization treatment through the main pipeline.

[0017] Further, the sterilization method further comprises the step of: A4, stopping the circulating hydrodynamic cavitation treatment of the circulating water, switching the hydrodynamic cavitation device outlet valve to the ultraviolet sterilization device, and flushing and cleaning the ultraviolet sterilization lamp tube; and the flushing water enters the spray pipeline.

[0018] The industrial circulating water sterilization method provided by the application combines the hydrodynamic cavitation and ultraviolet light, the water subjected to the hydrodynamic cavitation treatment is introduced into the ultraviolet sterilization device for ultraviolet sterilization, the microbial cell wall is destroyed by the mechanical action of the hydrodynamic cavitation, the sterilization is partially removed, and then the DNA and RNA of the microorganism are destroyed by the ultraviolet radiation, so that the sterilization effect is enhanced and the sterilization efficiency is improved.

[0019] The application aims to provide an industrial circulating water sterilization system. The industrial circulating water sterilization system applies the industrial circulating water sterilization method, and the sterilization system comprises a circulating water tank and a spray pipeline, the circulating water tank is provided with the spray pipeline above, and the sterilization system further comprises:

[0020] An ultraviolet sterilization device is provided with an outlet and an inlet; the inlet is connected to the circulating water tank, and the outlet is connected to the spray pipeline.

[0021] A hydrodynamic cavitation module comprises a high-pressure pump and a hydrodynamic cavitation device connected in sequence.

[0022] The hydrodynamic cavitation module is connected between the ultraviolet sterilization device and the circulating water tank.

[0023] The application aims to provide another industrial circulating water sterilization system.

[0024] The industrial circulating water sterilization system applies the industrial circulating water sterilization method, and the sterilization system comprises a circulating water tank and a spray pipeline, the circulating water tank is provided with the spray pipeline above, and the sterilization system further comprises:

[0025] The ultraviolet sterilization device is provided with an outlet and an inlet; the inlet is connected with a circulating water tank, and the outlet is connected with a spraying pipeline;

[0026] The water power cavitation module comprises a high-pressure pump and a water power cavitation device connected in sequence;

[0027] The sterilization system further comprises a main pipeline and a branch pipeline;

[0028] The ultraviolet sterilization device is arranged on the main pipeline, and the water power cavitation module is arranged on the branch pipeline;

[0029] The upstream of the branch pipeline is connected between the inlet of the ultraviolet sterilization device and the circulating water tank; and the downstream of the branch pipeline is connected with the circulating water tank.

[0030] As preferred, the water power cavitation device comprises a container with a decreasing inner diameter from top to bottom, an inlet pipe tangentially arranged on the periphery of the container, and an outlet pipe inserted into the container; the outlet pipe is provided with a Venturi structure; a flow guide member is arranged below the outlet pipe, the flow guide member is provided with a gas passage, and the gas passage is connected with an air inlet pipe; the air inlet pipe is connected with a negative pressure table and a one-way valve.

[0031] As preferred, a flushing pipeline is connected between the outlet pipe of the water power cavitation device and the inlet of the ultraviolet sterilization device.

[0032] As preferred, a pre-filter and a pressure pump are arranged between the circulating water tank and the inlet of the ultraviolet sterilization device.

[0033] As preferred, an eccentric tee joint is arranged between the main pipeline and the branch pipeline; and the outlet pipe of the water power cavitation device is connected with the tee joint.

[0034] As preferred, valves are arranged between the eccentric tee joint and the circulating water tank and between the eccentric tee joint and the pressure pump; and valves are arranged between the tee joint and the circulating water tank and between the tee joint and the flushing pipeline.

[0035] The present application aims to further provide another industrial circulating water sterilization system.

[0036] The sterilization system comprises a circulating water tank and a spraying pipeline, the circulating water tank is provided with the spraying pipeline above, and the sterilization system further comprises:

[0037] The ultraviolet sterilization device is provided with an outlet and an inlet; the inlet is connected with a circulating water tank, and the outlet is connected with a spraying pipeline;

[0038] The water power cavitation module comprises a high-pressure pump and a water power cavitation device connected in sequence;

[0039] The sterilization system further comprises a main pipeline and a branch pipeline;

[0040] The ultraviolet sterilization device is arranged in the main pipeline, and the hydraulic cavitation module is arranged in the branch pipeline.

[0041] The upstream of the branch pipeline is connected between the liquid outlet of the ultraviolet sterilization device and the spray pipeline.

[0042] Compared with the prior art, the present application has the following beneficial technical effects:

[0043] 1. Improved sterilization efficiency: the micro-bubbles generated by hydraulic cavitation release a huge amount of energy when they collapse, which is enough to destroy the cell structure of bacteria, while ultraviolet light achieves the purpose of sterilization by destroying the DNA and RNA of microorganisms. The combination of the two can enhance the killing effect on microorganisms from different mechanisms.

[0044] 2. The cavitation technology enhances the sterilization efficiency while eliminating the aggregation of white flocculent polymers; the elimination of white flocculent substances improves the transparency of water, the ultraviolet transmittance is higher, and the ultraviolet sterilization effect is enhanced.

[0045] 3. The combination of cavitation-ultraviolet light uses a pure physical sterilization process and does not produce harmful by-products, which can reduce the use of chemical disinfectants, is more friendly to the environment, and has low processing cost.

[0046] 4. Compared with the ultrasonic wave plus ultraviolet sterilization technology, the ultraviolet sterilization device is arranged in the main pipeline, and the hydraulic cavitation module is arranged in the branch pipeline, so that the large flow of water is directly delivered to the spray pipeline through the ultraviolet sterilization device, and the hydraulic cavitation device only circulates a small part of the water in the circulating water tank, meeting the demand of large flow of spray. The efficiency of ultrasonic cavitation is low and cannot meet the requirement of spray flow.

[0047] 5. The flushing pipeline connected with the liquid inlet of the ultraviolet sterilization device is arranged at the liquid outlet of the hydraulic cavitation device, which can flush the ultraviolet lamp at regular intervals, clean the dirt on the surface of the ultraviolet lamp, and improve the sterilization efficiency of the ultraviolet lamp. BRIEF DESCRIPTION OF DRAWINGS

[0048] Figure 1 The system flow diagram of the circulating water sterilization system embodiment 1.

[0049] Figure 2 The system flow diagram of the industrial circulating water sterilization system embodiment 2.

[0050] Figure 3 The system flow diagram of the industrial circulating water sterilization system embodiment 3.

[0051] Figure 4 The measured bacteria plate corresponding to different times under experimental conditions.

[0052] Figure 5 Figure: water clarity diagram corresponding to different times under experimental conditions.

[0053] Figure: circulating water tank 1, spray pipeline 2, ultraviolet sterilization device 3, liquid inlet 30, liquid outlet 31, hydrodynamic cavitation device 4, container 40, liquid inlet pipe 41, liquid outlet pipe 42, flow guide 43, negative pressure gauge 44, high-pressure pump 5, pre-filter 6, pressure pump 7, reducing tee 8, tee 9, main pipeline 10, first valve 100, second valve 101, branch pipeline 11, third valve 110, fourth valve 111, cleaning pipeline 12. DETAILED DESCRIPTION

[0054] The application will be further described below in combination with the drawings and specific embodiments:

[0055] The application provides an industrial circulating water sterilization method, comprising the following steps:

[0056] A1, the water to be sterilized in the circulating water tank is first filtered by the pre-filter to remove particulate impurities, and then is pumped into the hydrodynamic cavitation device by the high-pressure pump for hydrodynamic cavitation treatment, which utilizes cavitation mechanical action to destroy the cell wall of microorganisms and performs partial sterilization;

[0057] A2, the water treated by hydrodynamic cavitation is introduced into the ultraviolet sterilization device for further destruction of the cell wall of microorganisms and deep destruction of the DNA and RNA of microorganisms, thereby performing deep sterilization;

[0058] A3, the sterilized water is sprayed on the workpiece to be cleaned through the spray pipeline, and the cleaned water enters the circulating water tank for the next cycle;

[0059] In steps A1 and A2, the water to be sterilized in the circulating water tank can also be circulated into the hydrodynamic cavitation device for hydrodynamic cavitation treatment, and the water treated by the hydrodynamic cavitation is subjected to ultraviolet sterilization treatment after being treated for a certain number of times or for a certain period of time;

[0060] Alternatively, the circulating water is subjected to hydrodynamic cavitation treatment through the branch pipeline, and the circulating water is subjected to ultraviolet sterilization treatment through the main pipeline.

[0061] The sterilization method further comprises the step of: A4, stopping the hydrodynamic cavitation treatment of the circulating water tank, switching the liquid outlet valve of the hydrodynamic cavitation device to the ultraviolet sterilization device, and flushing and cleaning the ultraviolet sterilization lamp tube; the flushing water enters the spray pipeline.

[0062] The application also provides an industrial circulating water sterilization system, which applies the above-mentioned industrial circulating water sterilization method, and provides a circulating water sterilization system for the case where the spray flow requirement of the workpiece is low.

[0063] Example 1:

[0064] As Figure 1 shown, the sterilization system comprises: a circulating water tank 1, a spray pipeline 2, the circulating water tank 1 is provided with the spray pipeline 2, the spray pipeline 2 is provided with a plurality of spray heads, and the workpiece between the spray heads and the circulating water tank 1 is sprayed and cleaned, so as to prepare for subsequent electrophoretic coating. The sterilization system further comprises:

[0065] An ultraviolet sterilization device 3 is provided with a liquid inlet 30 and a liquid outlet 31; the liquid inlet 30 is connected with the circulating water tank 1, and the liquid outlet 31 is connected with the spray pipeline; the ultraviolet sterilization device 3 comprises a cylinder, an ultraviolet lamp tube arranged in the cylinder, and an end cover.

[0066] A hydrodynamic cavitation module comprises a high-pressure pump 5 and a hydrodynamic cavitation device 4 connected in sequence; the hydrodynamic cavitation module is connected in series with the ultraviolet sterilization device 3, and the hydrodynamic cavitation module is connected between the ultraviolet sterilization device 3 and the circulating water tank 1.

[0067] A pre-filter 6 and a valve are connected in sequence between the high-pressure pump 5 and the circulating water tank 1. The ultraviolet sterilization device 3 and the spray pipeline 2 are provided with valves.

[0068] The hydrodynamic cavitation device 4 comprises a container 40 with a decreasing inner diameter from top to bottom, a liquid inlet pipe 41 arranged tangentially at the periphery of the container, and a liquid outlet pipe 42 inserted into the container; the liquid outlet pipe is provided with a Venturi tube structure; the Venturi tube structure comprises a section with a decreasing inner diameter from bottom to top, a throat, and a section with an increasing inner diameter; a flow guide 43 is arranged below the liquid outlet pipe, the flow guide is provided with a gas passage, and the gas passage is connected with an air inlet pipe; the air inlet pipe is connected with a negative pressure gauge 44 and a one-way valve.

[0069] The circulating water introduced tangentially from the liquid inlet pipe 41 spirally flows downward in the container 40, accelerates, reaches the bottom, is guided by the flow guide 43 to spirally flow upward, is introduced into the liquid outlet pipe 42, and flows through the Venturi tube structure, enters the throat from the section with a decreasing inner diameter, passes through the throat at a high speed, forms a negative pressure, releases the gas in the liquid, forms a micro-bubble group, and causes hydrodynamic cavitation; after passing through the throat, the liquid enters the section with an increasing inner diameter, the liquid flow rate slows down, the static pressure increases, the micro-bubble group combines into a large bubble, and the bubble releases a huge energy when it collapses, which is enough to destroy the cell structure of bacteria.

[0070] For the circulating water sterilization with small spray flow, the connecting mode of Example 1 can be used. The circulating water in the circulating water tank is first subjected to hydrodynamic cavitation treatment by the hydrodynamic cavitation device, and the microbial cell wall is destroyed by cavitation mechanical action to partially sterilize the microorganisms. Then, the circulating water is flowed into the ultraviolet sterilization device from the liquid inlet 30, and after the ultraviolet lamp is powered on, the circulating water subjected to cavitation treatment is radiated by ultraviolet light to destroy the DNA and RNA of the microorganisms for deep sterilization. The circulating water subjected to deep sterilization is delivered to the spray pipeline and is used to flush the workpiece by the spray head to avoid the workpiece from being attached with microorganisms or white flocculent substances (bacterial corpses) which are brought into the subsequent electrophoresis line body to affect the electrophoretic coating.

[0071] Example 2

[0072] For the circulating water line body with large flow spraying demand, the application provides another industrial circulating water treatment system.

[0073] As shown in Figure 2 , the industrial circulating water sterilization system comprises a circulating water tank 1 and a spray pipeline 2. The spray pipeline 2 is provided above the circulating water tank 1, and a plurality of spray heads are arranged on the spray pipeline 2 to spray and clean the workpiece between the spray head and the circulating water tank 1, thereby preparing for the subsequent electrophoretic coating. The sterilization system further comprises an ultraviolet sterilization device 3 provided with a liquid inlet 30 and a liquid outlet 31. The liquid inlet 30 is connected to the circulating water tank 1, and the liquid outlet 31 is connected to the spray pipeline. The ultraviolet sterilization device 3 comprises a cylinder, an ultraviolet lamp arranged in the cylinder, and an end cover.

[0074] The hydrodynamic cavitation module comprises a high-pressure pump 5 and a hydrodynamic cavitation device 4 connected in sequence.

[0075] The ultraviolet sterilization device is arranged in the main pipeline 10, and the cavitation module is arranged in the branch pipeline 11. The upstream of the branch pipeline 11 is connected between the liquid inlet 30 of the ultraviolet sterilization device and the circulating water tank 1.

[0076] The main pipeline 10 is composed of circulating water tank 1-pre-filter 6-pressurizing pump 7-ultraviolet sterilization device 3-spraying pipeline 2; the branch pipeline 11 is composed of high-pressure pump 5-hydraulic cavitation device 4; the high-pressure pump is connected with the two liquid inlet pipes 41 of the hydraulic cavitation device 4, and a positive pressure gauge is arranged between the high-pressure pump 5 and the hydraulic cavitation device 4. The liquid outlet pipe 42 of the hydraulic cavitation device 5 is divided into two routes, one of which is connected with the circulating water tank, and the other of which is connected with the ultraviolet sterilization device, and this route serves as a cleaning pipeline 12. The water outlet of the hydraulic cavitation device is used for timing flushing of the ultraviolet lamp tube, and the dirt on the surface of the ultraviolet lamp tube is cleaned. The main pipeline 10 and the branch pipeline 11 are connected through the different-diameter tee joint 8. The different-diameter tee joint 8 is respectively provided with the first valve 100 and the second valve 101 between the pre-filter and the pressurizing pump 7; the liquid outlet pipe 42 of the hydraulic cavitation device 4 is connected with the tee joint 9, and the tee joint 9 is respectively provided with the third valve 110 and the fourth valve 111 between the circulating water tank 1 and the cleaning pipeline 12.

[0077] The working principle of example 2 is as follows:

[0078] The first valve 100 and the third valve 110 are opened, and the water to be sterilized in the circulating water tank 1 is subjected to the circulating hydraulic cavitation treatment. After the cavitation is performed for several times or for several time periods, the second valve 101 is opened, the water subjected to the cavitation treatment in the circulating water tank 1 is introduced into the ultraviolet sterilization device 3, is further sterilized by the ultraviolet light, and the sterilized water is transported to the spraying pipeline 3 to spray and clean the workpiece. In this process, the cavitation treatment is performed for several times, then the ultraviolet sterilization device is introduced, and the spraying efficiency is low, but the treatment effect is better.

[0079] Alternatively, the first valve 100, the third valve 110 and the second valve 101 are opened, the water in the circulating water tank 1 is subjected to the circulating cavitation treatment through the branch pipeline, and the ultraviolet sterilization through the main pipeline is used to supply the liquid to the spraying pipeline. In this process, the workpiece spraying is not affected, the large-flow liquid supply of the spraying pipeline is ensured, and the final treatment effect of the circulating water is not affected because the water is always circulating.

[0080] After the circulating hydraulic cavitation treatment is performed for several times or for several time periods, the third valve 110 is closed, the cavitation treatment of the circulating water tank is stopped, the fourth valve 111 is opened, the water outlet of the hydraulic cavitation device is flushed through the flushing pipeline 12, the ultraviolet lamp tube in the ultraviolet sterilization device 3 is flushed, and the flushing water is introduced into the spraying pipeline. The flushing is also subjected to the cavitation-ultraviolet sterilization treatment.

[0081] Example 3 is as follows:

[0082] For the large-flow spraying requirement, the application further provides an industrial circulating water sterilization system, which is as follows: Figure 3As shown, the sterilization system comprises: a circulating water tank 1, a spray pipeline 2, the circulating water tank 1 is provided with the spray pipeline 2, the spray pipeline 2 is provided with a plurality of spray heads, for spraying and cleaning the workpiece between the spray head and the circulating water tank 1, to prepare for subsequent electrophoretic coating.

[0083] The sterilization system further comprises: a UV sterilization device 3, provided with a liquid inlet 30 and a liquid outlet 31; the liquid inlet 30 is connected to the circulating water tank 1, and the liquid outlet 31 is connected to the spray pipeline; the UV sterilization device 3 comprises a cylinder, a UV lamp tube arranged in the cylinder, and an end cover.

[0084] A hydrodynamic cavitation module, the hydrodynamic cavitation module comprises a high-pressure pump 5 and a hydrodynamic cavitation device 4 connected in sequence.

[0085] The UV sterilization device is arranged in the main pipeline 10, and the cavitation module is arranged in the branch pipeline 11; the branch pipeline 11 is connected between the liquid outlet 31 of the UV sterilization device and the spray pipeline 2.

[0086] The main pipeline 10 is composed of: the circulating water tank 1-UV sterilization device 3-spray pipeline 2; the branch pipeline 11 is composed of: high-pressure pump 5-hydrodynamic cavitation device 4; the main pipeline 10 and the branch pipeline 11 are connected through a reducing tee 8, which is divided into two paths from the liquid outlet 31 of the UV sterilization device 3, one path is connected to the spray pipeline 2, and the other path is connected to the branch pipeline 11; the reducing tee 8 is provided with a valve between the spray pipeline and the branch pipeline 11; the liquid outlet pipe 42 of the hydrodynamic cavitation device 4 is connected to a tee 9, which is divided into two paths, one path is connected to the spray pipeline 2, and the other path is connected to the liquid inlet 30 of the UV sterilization device, which serves as a cleaning pipeline 12; the tee 9 is provided with a valve between the circulating water tank 1 and the cleaning pipeline 12. The cleaning pipeline 12 is connected to the reducing tee 8 between the main pipeline 10, and the reducing tee 8 is provided with a valve between the circulating water tank and the cleaning pipeline.

[0087] The working principle of embodiment 3 is as follows:

[0088] At the beginning of the use of industrial circulating water, the content of microorganisms is relatively low, at this time most of the circulating water uses the UV sterilization device 3 of the main pipeline to sterilize the circulating water tank, a small amount of circulating water is treated by hydrodynamic cavitation after UV sterilization, and the water after cavitation treatment is introduced into the spray pipeline to spray and clean the workpiece, to prepare for subsequent electrophoretic coating, and the spray water enters the circulating water tank 1.

[0089] After the circulating water is used for a period of time, although the circulating water will breed bacteria, the water is always circulating, the UV sterilization device and the hydrodynamic cavitation device are started at the same time, and finally all the water is treated by hydrodynamic cavitation and UV sterilization, which can ensure that the circulating water is always in a state that the number of bacteria does not exceed the standard. The water usage time is prolonged without frequent water change, and the water usage amount is saved.

[0090] After a period of cavitation treatment, the outlet pipe 42 of the hydrodynamic cavitation device is switched to the flushing pipeline 12 through the valve, and the ultraviolet lamp in the ultraviolet sterilization device 3 is flushed by the water outlet of the hydrodynamic cavitation device, and the dirt on the surface of the ultraviolet lamp is cleaned, and the flushing water is introduced into the spray pipeline. While flushing, cavitation-ultraviolet sterilization treatment is also being performed.

[0091] The industrial circulating water sterilization system and method are further described below in combination with experimental data, but they cannot be understood as limiting the scope of protection of the application.

[0092] A 70L cultured bacterial water sample was tested, and the steps were as follows:

[0093] 1. Turn on the ultraviolet device with a rated power of 150W;

[0094] 2. Switch the flow path to the hydrodynamic cavitation and ultraviolet sterilization pipeline, turn on the pump for 5 minutes, and then stop the pump;

[0095] 3. Switch the flow path to the ultraviolet sterilization pipeline, turn on the pump for 55 minutes, and then stop the pump;

[0096] 4. Repeat steps 2-3 a total of 4 times, for a total of 4 hours;

[0097] 5. Sample at 5 minutes, 10 minutes, 15 minutes, 30 minutes, 1 hour, 2 hours and 4 hours of the experiment respectively, and detect the number of bacteria.

[0098] As shown in Figure 4 , because the number of bacteria in the initial bacterial solution is large (>10 7 CFU / mL), the water sample appears a relatively obvious white turbidity phenomenon, and after 30 minutes of treatment, the number of bacteria decreases by 3 orders of magnitude (1000 times), to 10 4 CFU / mL, but at this time the turbidity of the water sample increases, and this phenomenon is caused by the generation of white polymers that wrap bacteria while the remaining colonies activate their protection mechanisms under ultraviolet irradiation. At this time, ultraviolet sterilization continues but the efficiency decreases.

[0099] As shown in Figure 5 , the water samples after 2 hours and 4 hours of reaction are very clear, and have no difference from pure water, and the bacterial content has decreased to less than 10 3 CFU / mL after 4 hours.

[0100] The above merely illustrates the specific embodiments of the present application, but the technical features of the present application are not limited thereto. Any simple change, equivalent replacement or modification made on the basis of the present application to solve the basically same technical problem and realize the basically same technical effect shall be included in the protection scope of the present application.

Claims

1. A method for sterilizing industrial circulating water, characterized in that: The sterilization method uses a sterilization system, which includes: a main pipeline, a circulating water tank-ultraviolet sterilization device-spray pipeline; a branch pipeline, a high-pressure pump-hydraulic cavitation device; the upstream of the branch pipeline is connected between the liquid inlet of the ultraviolet sterilization device and the circulating water tank; the downstream of the branch pipeline is connected to the circulating water tank; the method includes the following steps: A1. Perform hydrodynamic cavitation treatment on the water to be sterilized in the circulating water tank, using the mechanical action of hydrodynamic cavitation to destroy the cell walls of microorganisms and perform partial sterilization. Circulate the water to be sterilized through the branch pipes and perform the circulatory hydrodynamic cavitation treatment a certain number of times or for a certain period of time. A2. The water in the circulating water tank that has undergone cavitation treatment is introduced into the UV sterilizer through the main pipe for deep sterilization. A3. Sterilized water is sprayed on the workpiece to be cleaned through the spray pipe, and the cleaned water enters the circulating water tank for the next cycle; A4. Stop the hydraulic cavitation treatment of the circulating water tank, switch the outlet valve of the hydraulic cavitation device to the ultraviolet sterilization device, and flush and clean the ultraviolet sterilization lamp; the flushing water enters the spray pipeline.

2. The industrial circulating water sterilization method according to claim 1, characterized in that: In step A1, the water to be sterilized in the circulating water tank is first filtered through a pre-filter to remove particulate impurities in the water, and then pumped into the hydrodynamic cavitation device by a high-pressure pump for hydrodynamic cavitation treatment.

3. An industrial circulating water sterilization system, applying the industrial circulating water sterilization method according to claim 1 or 2, wherein the sterilization system comprises: Circulating water tank, spray pipeline, a spray pipeline is provided above the circulating water tank, characterized in that the sterilization system also includes: The ultraviolet sterilization device is provided with a liquid outlet and a liquid inlet; the liquid inlet is connected to the circulating water tank, and the liquid outlet is connected to the spray pipeline; A hydrodynamic cavitation module, comprising a high-pressure pump and a hydrodynamic cavitation device connected in sequence; The sterilization system further includes a main pipeline and a branch pipeline; The ultraviolet sterilization device is arranged on the main pipeline, and the hydrodynamic cavitation module is arranged on the branch pipeline; The upstream of the branch line is connected between the liquid inlet of the ultraviolet sterilizer and the circulating water tank; the downstream of the branch line is connected to the circulating water tank; A reducing tee is provided between the main pipeline and the branch pipeline; and the liquid outlet pipe of the hydrodynamic cavitation device is connected to the tee.

4. The industrial circulating water sterilization system according to claim 3, characterized in that: The hydrodynamic cavitation device includes: a container with an inner diameter that decreases from top to bottom, a liquid inlet pipe arranged tangentially to the circumference of the container, and a liquid outlet pipe inserted into the interior of the container; the liquid outlet pipe is provided with a Venturi tube structure; a guide member is provided below the liquid outlet pipe, a gas channel is provided in the guide member, and the gas channel is connected to the air inlet pipe; the air inlet pipe is connected to a negative pressure gauge and a one-way valve.

5. The industrial circulating water sterilization system according to claim 3, characterized in that: A flushing pipeline is connected between the liquid outlet pipe of the hydrodynamic cavitation device and the liquid inlet of the ultraviolet sterilization device.

6. The industrial circulating water sterilization system according to claim 3, characterized in that: A pre-filter and a pressure pump are provided between the circulating water tank and the liquid inlet of the ultraviolet sterilizing device.

7. The industrial circulating water sterilization system according to claim 3, characterized in that: Valves are provided between the reducing tee and the circulating water tank and the pressure pump; valves are provided between the reducing tee and the circulating water tank and the flushing pipeline.

8. Industrial circulating water sterilization system, the sterilization system comprising: Circulating water tank, spray pipeline, a spray pipeline is provided above the circulating water tank, characterized in that the sterilization system also includes: The ultraviolet sterilization device is provided with a liquid outlet and a liquid inlet; the liquid inlet is connected to the circulating water tank, and the liquid outlet is connected to the spray pipeline; A hydrodynamic cavitation module, comprising a high-pressure pump and a hydrodynamic cavitation device connected in sequence; The sterilization system further includes a main pipeline and a branch pipeline; The ultraviolet sterilization device is arranged on the main pipeline, and the hydrodynamic cavitation module is arranged on the branch pipeline; The upstream of the branch line is connected between the liquid outlet of the ultraviolet sterilizer and the spray line; the downstream of the branch line is connected to the spray line; The main pipeline and the branch pipeline are connected by a reducing tee; the liquid outlet of the ultraviolet sterilizer is divided into two routes, one of which is connected to the spray pipeline and the other is connected to the branch pipeline; The liquid outlet pipe of the hydrodynamic cavitation device is connected to a tee, and the liquid outlet pipe is divided into two paths, one path is connected to the spray pipeline, and the other path is connected to the liquid inlet of the ultraviolet sterilization device, which serves as a cleaning pipeline.

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