Sterilization system of closed circulating system

Abstract

The present application belongs to the technical field of water treatments using circulating systems. Provided is a sterilization system of a closed circulating system. The sterilization system comprises a medium-loaded main circulation loop, and a heat exchanger and a circulation pump, which are connected to the main circulation loop in series. The sterilization system further comprises a circulation bypass and an ultraviolet sterilization device provided in the circulation bypass, wherein the circulation bypass is connected in parallel to some sections of the main circulation loop. In the sterilization system of a closed circulation system in the present application, the circulation bypass is connected in parallel to some sections of the main circulation loop, and the ultraviolet sterilization device is provided in the circulation bypass, thereby overcoming defects caused by the utilization of a chemical sterilization mode in the closed system.

Description

A sterilization treatment system for a closed circulation system Technical Field

[0001] The present application relates to the technical field of water treatment in a circulation system, and in particular to a sterilization treatment system for a closed circulation system. Background Art

[0002] Closed circulating water systems, especially those at room temperature, often have bacterial growth problems, especially in closed circulating water systems used in certain production processes. Lubricating grease introduced by machinery and equipment, material leakage, and organic matter from chemical degradation can easily promote bacterial growth. In severe cases, slime deposits will form on the inner walls of system pipes, equipment, and heat exchangers, leading to accelerated corrosion and even perforation of the metal under the deposits, as well as a sharp drop in the heat exchange efficiency of the heat exchanger. Therefore, for such closed circulating water systems, as with open cooling water systems, special attention should be paid to bacterial control on a daily basis. The conventional bacterial control method is to regularly and long-term add fungicides. However, the use of fungicides often has the following limitations:

[0003] (1) Non-oxidizing fungicides such as isothiazolinone, glutaraldehyde, and quaternary ammonium salts are prone to drug resistance. Long-term use will result in poor bactericidal effects, leading to increasing dosages and higher costs.

[0004] (2) Oxidizing fungicides, such as sodium hypochlorite, chloramine, and peracetic acid, are less likely to induce drug resistance, but they can easily cause pH changes and have a short sterilization duration, quickly leading to a rebound in bacterial counts. Furthermore, oxidizing fungicides can accelerate metal corrosion, and long-term use can shorten the service life of pipeline equipment.

[0005] (3) Most fungicides are organic matter, which will eventually degrade and transform into organic matter with no bactericidal activity and accumulate in the system, causing COD to rise. In turn, they become a nutrient source for bacteria and promote their reproduction, which increases the difficulty of sterilization control. The amount of fungicide added will also increase, eventually forming a vicious cycle.

[0006] (4) A closed circulating water system is different from an open system. An open system needs to discharge sewage on a daily basis, which is equivalent to continuously replacing the system water. A closed system generally does not discharge sewage on a daily basis. However, as COD increases and bacteria control becomes increasingly difficult, sewage replacement has to be carried out. This increases water consumption. At the same time, drainage can easily cause system pressure fluctuations, bringing risks to the normal operation of the system.

[0007] (5) Chemical fungicides are often highly toxic or corrosive, and there are certain safety risks during transportation, storage, and use. In addition to the cost of the agent itself, there are also costs for transportation, storage, labor, and dosing equipment.

[0008] In summary, the present application aims to provide a sterilization treatment system for a closed circulation system, which is suitable for sterilizing media in closed circulation systems such as central air-conditioning water or process cooling water for production.

[0009] Application Contents

[0010] In view of the problems of the prior art mentioned above, the purpose of this application is to provide a sterilization treatment system for a closed circulation system, which overcomes the defects of using chemical sterilization methods in a closed system by connecting a flow bypass in parallel to some sections of the main circulation pipeline and arranging an ultraviolet sterilization device on the flow bypass.

[0011] To achieve the above-mentioned objectives and other related objectives, the first aspect of the present application provides a sterilization treatment system of a closed circulation system.

[0012] In one possible embodiment, the ultraviolet sterilization device is connected in parallel with the heat exchanger; and / or the ultraviolet sterilization device is connected in parallel with the circulation pump.

[0013] In one embodiment, the ultraviolet sterilization device includes an ultraviolet sterilizer, a water inlet valve, and a water outlet valve connected in series in the flow bypass, and the water inlet valve and the water outlet valve are respectively arranged upstream and downstream of the ultraviolet sterilizer.

[0014] As a preferred solution, the ultraviolet sterilization device further includes a flow meter connected in series to the flow bypass, and the flow meter is located between the water inlet valve and the ultraviolet sterilizer.

[0015] As a preferred solution, the flowmeter is selected from any one of a water meter flowmeter, an electromagnetic flowmeter, a differential pressure flowmeter, a rotor flowmeter, a turbine ultrasonic flowmeter, a calorimetric flowmeter or a photoelectric flowmeter.

[0016] In one embodiment, the ultraviolet sterilization device further includes a pipeline filter connected in series to the flow bypass, and the pipeline filter is located upstream of the flow meter.

[0017] In one embodiment, the wavelength of the UV lamp of the UV sterilizer is 200-300 nm; and / or the UV irradiation dose of the UV sterilizer is 20-100 mJ / cm 2 .

[0018] In one possible implementation manner, a sampling valve is provided on the main circulation pipeline; and / or a sampling valve is provided at the outflow end of the ultraviolet sterilization device.

[0019] In one possible implementation manner, the medium processing capacity of the ultraviolet sterilization device is 3-10% of the medium holding capacity of the sterilization treatment system.

[0020] In one embodiment, the medium is selected from central air-conditioning water or production process cooling water.

[0021] The sterilization treatment system of the closed circulation system provided in this application has but is not limited to the following beneficial effects:

[0022] 1) The treatment system of the present application reduces the daily sewage discharge of the circulating water system by connecting a flow bypass in parallel to a part of the main circulation pipeline and arranging an ultraviolet sterilization device on the flow bypass. In this closed system, ultraviolet sterilization is used to reduce the daily sewage discharge of the circulating water system. In addition, the cost of disinfectants, operating labor and investment in dosing equipment are saved.

[0023] 2) The UV sterilizer is installed in a bypass mode, which has no or minimal impact on the operation of the entire circulating water system, pressure, water temperature, and heat exchange efficiency of the heat exchanger. Preferably, the UV sterilizer is connected in parallel with the heat exchanger, or in parallel with the circulating pump.

[0024] 3) A flow meter is installed upstream of the UV sterilizer to control the flow of the medium entering the UV sterilizer. Preferably, the medium processing capacity of the UV sterilizer is 3-10% of the medium holding capacity of the sterilization treatment system. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] FIG1 is a schematic structural diagram of a first sterilization treatment system of a closed circulation system according to Example 1 of the present application.

[0026] FIG2 is a schematic structural diagram of a second sterilization treatment system of the closed circulation system described in Example 2 of the present application.

[0027] FIG3 is a schematic structural diagram of a third sterilization treatment system of the closed circulation system described in Example 3 of the present application.

[0028] Description of Reference Numerals

[0029] 1. Circulation main pipeline

[0030] 2 Heat exchanger

[0031] 3 Circulation pump

[0032] 4 Flow bypass

[0033] 5. UV sterilization device

[0034] 51 UV sterilizer

[0035] 52 Water inlet valve

[0036] 53 Water outlet valve

[0037] 54 flow meter

[0038] 55 Pipeline Filter

[0039] 6 Sampling valve DETAILED DESCRIPTION

[0040] Regarding the terminology in this application: "upstream" and "downstream" are directional terms, which are customary terms in process systems and are divided into upstream and downstream according to the conveying direction or flow direction of the process medium. For example, along the flow direction of the medium, A is located downstream of B, that is, the medium enters B first and then enters A. "The medium holding capacity of the treatment system" is a conventional expression in production. In this application, it refers to the content of the medium stored in the entire closed circulation system (such as the medium content in the pipeline and the medium content in the equipment connected to the pipeline). The orientation or positional relationship indicated in this application is based on the orientation or positional relationship shown in the accompanying drawings. It is only for the convenience of describing this application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it cannot be understood as a limitation to this application. In addition, the well-known technologies usually associated with commonly used industrial devices are not described in detail. Those skilled in the art who are not described can understand them according to the conventional methods in the prior art. For example, ultraviolet sterilizers can be purchased commercially. The following describes the implementation of the present application through specific embodiments. People familiar with this technology can easily understand other advantages and effects of the present application from the contents disclosed in this specification.

[0041] Please refer to Figures 1-3. It should be noted that the structures, proportions, sizes, etc. illustrated in the drawings in this specification are intended solely to facilitate understanding and reading by those skilled in the art, and are not intended to limit the applicable conditions for implementation of this application. Therefore, they have no substantive technical significance. Any structural modifications, changes in proportions, or adjustments in size, provided they do not affect the efficacy and objectives of this application, shall still fall within the scope of the technical content disclosed in this application.

[0042] Example 1

[0043] Referring to Figures 1-3 , each embodiment provides a sterilization treatment system for a closed circulation system, comprising a main circulation pipeline 1 carrying a medium, a heat exchanger 2 connected in series to the main circulation pipeline 1, and a circulation pump 3. The sterilization treatment system also includes a circulation bypass 4 and a UV sterilizer 5 disposed in the circulation bypass 4 . The circulation bypass 4 is connected in parallel with a portion of the main circulation pipeline 1 .

[0044] Specifically, some sections of the main circulation pipeline 1, such as sections with loads, are used to facilitate the medium in the main circulation pipeline 1 to enter the circulation bypass 4, without affecting the operation, pressure, and water temperature of the entire circulating water system, and without affecting the heat exchange effect of the heat exchanger in the closed circulating water system. More specifically, for example, in Figure 1, the ultraviolet sterilization device 5 is connected in parallel with the heat exchanger 2. For example, in Figure 2, the ultraviolet sterilization device 5 is connected in parallel with the circulation pump 3. For example, in Figure 3, the ultraviolet sterilization device 5 is connected in parallel with the heat exchanger 2 and the circulation pump 3. As described above, by connecting the circulation bypass 4 in parallel with some sections of the main circulation pipeline 1 and arranging the ultraviolet sterilization device 5 on the circulation bypass 4, the daily sewage discharge of the circulating water system is reduced by ultraviolet sterilization in the closed system. In addition, the cost of disinfectants, operating labor and investment in dosing equipment are saved.

[0045] In a preferred embodiment, the ultraviolet sterilization device 5 includes an ultraviolet sterilizer 51, an inlet valve 52, and an outlet valve 53 connected in series in the flow bypass 4, and the inlet valve 52 and the outlet valve 53 are respectively arranged upstream and downstream of the ultraviolet sterilizer 51. Specifically, the ultraviolet sterilizer is a commercially available ultraviolet sterilizer or customized from a manufacturer of ultraviolet sterilizers. The performance that the selected or customized ultraviolet sterilizer needs to meet is that the wavelength of the ultraviolet lamp is 200 to 300nm. Optimally, the wavelength of the ultraviolet lamp of the ultraviolet sterilizer is 253.7nm. The ultraviolet irradiation dose of the ultraviolet sterilizer 51 is 20 to 100mJ / cm 2 More specifically, the flow rate is adjusted by the opening of the water inlet valve 52, and the water outlet valve 53 remains fully open when the system is operating normally.

[0046] In a preferred embodiment, the UV sterilizer 5 further includes a flow meter 54 connected in series with the flow bypass 4. The flow meter 54 is located between the water inlet valve 52 and the UV sterilizer 51. This facilitates debugging of the optimal sterilization flow rate before the UV sterilizer 5 is put into full operation, or facilitates flow monitoring during operation and debugging of the flow rate in conjunction with the water inlet valve 52. Specifically, the flow meter 54 is selected from any one of a water meter, an electromagnetic flow meter, a differential pressure flow meter, a rotor flow meter, a turbine ultrasonic flow meter, a calorimetric flow meter, or a photoelectric flow meter.

[0047] In a preferred embodiment, the medium processing capacity of the ultraviolet sterilization device 5 is 3-10% of the medium holding capacity of the sterilization treatment system. Since the bypass flow (the medium processing capacity of the ultraviolet sterilization device) is only 3-10% of the medium holding capacity of the sterilization treatment system, it is an extremely small flow rate relative to the circulation flow of the entire closed circulating water system, and has no effect or very little effect on the operation, pressure, water temperature, heat exchange effect of the heat exchanger, etc. of the entire circulating water system. For example: the medium holding capacity of a closed system is 100m 3 , the circulation volume can generally reach hundreds of m 3 / h, calculated based on 3-10% of the holding capacity, the medium processing capacity of the ultraviolet disinfection device is 3-10m 3 / h, relative to hundreds of m 3 / h is a very small flow loss compared to the total flow.

[0048] In a preferred embodiment, the UV sterilizer 5 further includes a pipe filter 55 connected in series to the bypass 4. The pipe filter 55 is located upstream of the flow meter 54. The pipe filter 55 is provided to prevent particulate impurities from impacting the quartz sleeve inside the UV sterilizer 51 under the influence of high water flow, causing the sleeve to wear or break. The pipe filter 55 is, for example, a stainless steel basket pipe filter.

[0049] In a preferred embodiment, a sampling valve is provided at the outflow end of the ultraviolet sterilization device to determine the instantaneous sterilization effect of the ultraviolet sterilizer 51. The instantaneous sterilization effect should ensure that the number of bacteria is ≤100 / ml. The instantaneous sterilization effect is ensured by ensuring the ultraviolet irradiation dose of the ultraviolet sterilizer 51 and controlling the flow rate flowing through the ultraviolet sterilizer 51. If the sterilization effect is greater than 100 / ml, it means that the instantaneous sterilization effect does not meet the requirements. The outlet valve 53 of the ultraviolet sterilizer 51 needs to be appropriately adjusted to reduce the flow rate flowing through the ultraviolet sterilizer 51 to achieve the purpose of improving the sterilization effect. The flow rate is reduced by 1% of the system's water volume each time.

[0050] In a preferred embodiment, a sampling valve 6 is provided on the main circulation pipeline 1, which is used to regularly monitor the bacterial count in the medium of the main circulation pipeline 1. After the instantaneous sterilization effect of the UV germicidal lamp reaches the control requirement of ≤100 bacteria / ml, the bacterial count in the main circulation pipeline 1 of the closed circulation system is monitored every 2-3 days. The main pipe bacterial count control standard is determined according to the actual process control requirements. Generally, closed circulating water systems are controlled to have a bacterial count below 1,000 or 10,000 bacteria / ml. When the main pipe bacterial count meets the control process requirement, it indicates that the flow rate of the UV germicidal lamp and the sterilization effect on the system have reached a balance, and this state should be maintained to maintain the sterilization effect. If the bacterial count in the main circulation pipeline 1 does not meet the control process requirement, it indicates that the flow rate of the UV germicidal lamp and the sterilization effect on the system have not yet reached a balance, and the flow rate through the UV germicidal lamp needs to be further adjusted. The method for further adjusting the flow rate through the UV sterilizer 51 is to first reduce the flow rate by 1% of the system's water volume at a time. After each reduction, every 2-3 days, check the total bacterial count in the system's main circulation pipeline 1 to see if it meets the process control requirements. If it does not, reduce the flow rate by another 1% and then check the total bacterial count in the main circulation pipeline. If the flow rate is reduced until it falls below 3% of the retained water volume, it means that the reduced flow rate is no longer able to meet the required bacterial count in the main circulation pipeline. This is because, although reducing the flow rate improves the sterilization efficiency of the water flowing through it, it also prolongs the sterilization cycle of the entire system's retained water volume. The bacterial reproduction rate is faster than the rate at which they are killed, and the bacteria continue to grow. In this case, the flow rate through the UV sterilizer 51 should be increased to shorten the sterilization cycle of the entire system's retained water volume, with each increase being 1% of the system's retained water volume. After each increase in flow rate, every 2-3 days, check the total bacterial counts at both the UV sterilizer 51 outlet and the system main pipe to see if they meet the required counts. If both the UV sterilizer 51 outlet and the main pipe 1 meet the required counts, it indicates that the flow rate through the UV sterilizer 51 is balanced with the system's sterilization effectiveness. If the UV sterilizer 51 outlet meets the required counts but the main pipe does not, increase the flow rate by another 1% and repeat the above steps. Once the UV germicidal lamp is commissioned and operational, regular bacterial testing should be performed. If the flow rate is increased to a value exceeding 10% of the retained water volume, this indicates that the increased flow rate is no longer sufficient to meet the required bacterial count in the main pipe 1. If neither increasing nor decreasing the flow rate meets the required bacterial count in the main pipe, it indicates that the UV sterilizer 51 is faulty and requires repair or replacement.

[0051] Example 2

[0052] Application object: Cooling water system for closed body welding process in a certain automobile manufacturing plant;

[0053] System parameters: water capacity 200m 3 , daily operating water temperature is 28-32℃;

[0054] Original problem: After one year of operation, the system was found to have exceeded the process control standard of 10,000 cells / ml. Subsequently, an isothiazolinone fungicide was added, and the bacteria were barely under control within two months. However, from the third month onwards, the bacteria began to get out of control, and even adding several times the isothiazolinone fungicide was ineffective. The system was then switched to a fungicide compounded with glutaraldehyde and quaternary ammonium salts. This was added once a month for the first three months, with good results, and the bacteria were controlled at around 1,000 cells / ml. However, from the fourth month onwards, the bacteria count could no longer be controlled. After one addition of fungicide, the count rebounded to 10,000 cells / ml two weeks later, and rebounded to 20,000 cells / ml one week after the next addition. At the same time, the cooling water pipes of the welding robots at the end of the workshop became clogged with biological sticky substances, resulting in an abnormal line stoppage. This shows that non-oxidizing fungicides are very likely to develop drug resistance after a period of use. The bactericidal effect cannot be guaranteed, and the cost of the agent has skyrocketed. In an emergency, the oxidizing bactericide Euchloramine was added instead, which had a good impact bactericidal effect and the bacterial count dropped significantly to 100 / ml. However, it rebounded to over 10,000 / ml within a week. At the same time, the corrosion problem caused by the oxidizing bactericide caused a rapid increase in water quality indicators such as total iron and total copper, and the total iron exceeded the control standard of 2mg / L. The rust increased the turbidity of the system, and the blockage of the terminal pipe became more serious.

[0055] The solution of this example is to install a UV sterilizer 5 in the closed car body welding process cooling water system. The flow rate through the UV sterilizer 5 is designed to be 8% of the total water volume of the entire system, that is, 16m 3 / h, the power of the UV sterilizer 51 is 280W. It is installed in parallel with the circulation pump 3. That is, according to the direction of water flow, the flow bypass 4 is installed with an inlet butterfly valve, a stainless steel basket pipe filter, a water meter for measuring flow, the UV sterilizer 51, and a water outlet butterfly valve. First, adjust the flow rate to 16m3 / h, test the bacterial count at the outlet of the UV sterilizer 51 to 1000 / ml, and reduce the water retention by 1% to 14m3 / h. 3 / h, the number of bacteria at the outlet was measured at 100m 3 After 3 days, the total bacterial count in the circulating pipeline was 10,000 / ml. The upward trend of bacteria was under control, but it still did not meet the standard. The water flow rate was further reduced by 1%, that is, to 12m 3 The system's main pipe was tested weekly for total bacterial counts, maintaining a constant flow of 5,000 to 7,000 cells / ml for the first three weeks. Starting in the fourth week, the count gradually decreased, reaching around 1,000 cells / ml by the sixth week and remaining at that level. This resolved the bacterial growth issue, avoiding the risk of production line downtime and significantly saving on biocide costs.

[0056] The above description of the embodiments is intended to facilitate understanding and application of the present application by those skilled in the art. It will be apparent that those skilled in the art can readily make various modifications to these embodiments and apply the general principles described herein to other embodiments without expending any creative effort. Therefore, the present application is not limited to the embodiments described herein, and improvements and modifications made by those skilled in the art based on the disclosure of this application without departing from the scope and spirit of this application are within the scope of this application.

Claims

1. A sterilization treatment system of a closed circulation system, characterized in that: It comprises a circulating main pipeline (1) carrying a medium, a heat exchanger (2) and a circulating pump (3) connected in series to the circulating main pipeline (1); The sterilization treatment system further comprises a circulation bypass (4) and an ultraviolet sterilization device (5) arranged on the circulation bypass (4); the circulation bypass (4) is connected in parallel with a partial section of the circulation main pipeline (1).

2. The sterilization treatment system according to claim 1, characterized in that: The ultraviolet sterilization device (5) is connected in parallel with the heat exchanger (2); and / or the ultraviolet sterilization device (5) is connected in parallel with the circulation pump (3).

3. The sterilization treatment system according to claim 1, characterized in that: The ultraviolet sterilization device (5) comprises an ultraviolet sterilizer (51), a water inlet valve (52) and a water outlet valve (53) which are connected in series in the circulation bypass (4), and the water inlet valve (52) and the water outlet valve (53) are respectively arranged upstream and downstream of the ultraviolet sterilizer (51).

4. The sterilization treatment system according to claim 3, characterized in that: The ultraviolet sterilization device (5) further comprises a flow meter (54) connected in series to the circulation bypass (4), wherein the flow meter (54) is located between the water inlet valve (52) and the ultraviolet sterilizer (51).

5. The sterilization treatment system according to claim 4, characterized in that: The flow meter (54) is selected from any one of a water meter flow meter, an electromagnetic flow meter, a differential pressure flow meter, a rotor flow meter, a turbine ultrasonic flow meter, a calorimetric flow meter or a photoelectric flow meter.

6. The sterilization treatment system according to claim 4, characterized in that: The ultraviolet sterilization device (5) further comprises a pipeline filter (55) connected in series to the circulation bypass (4), and the pipeline filter (55) is located upstream of the flow meter (54).

7. The sterilization treatment system according to any one of claims 2 to 6, characterized in that: The wavelength of the ultraviolet lamp of the ultraviolet sterilizer (51) is 200-300 nm; and / or the ultraviolet irradiation dose of the ultraviolet sterilizer (51) is 20-100 mJ / cm 2 .

8. The sterilization treatment system according to any one of claims 1 to 6, characterized in that: The main circulation pipeline (1) is provided with a sampling valve (6); and / or the outflow end of the ultraviolet sterilization device is provided with a sampling valve.

9. The sterilization treatment system according to any one of claims 1 to 6, characterized in that: The medium processing capacity of the ultraviolet sterilization device (5) is 3-10% of the medium holding capacity of the sterilization treatment system.

10. The sterilization treatment system according to any one of claims 1 to 6, characterized in that: The medium is selected from central air-conditioning water or process cooling water for production.

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