A method of pulsing ice slurry cleaning feed water lines

Abstract

This invention discloses a pulsed ice slurry cleaning method for water supply pipelines, belonging to the field of water supply pipeline cleaning technology. This invention aims to solve the core contradiction in existing ice slurry cleaning technologies: high flow rates result in short effective cleaning times, while low flow rates lead to insufficient shear force. The invention includes the following steps: pipeline pretreatment, high-concentration ice slurry injection, pulsed carrier fluid-driven flushing, and post-cleaning treatment. First, high-concentration ice slurry (1 / 3 volume) is injected into the pipeline to be cleaned. Then, by controlling the carrier fluid flow rate and the opening of the valve at the pipeline end, alternating between valve-closing pressurization and valve-opening slow release phases, a periodic pulse cycle is formed. This invention achieves a synergistic improvement in shear force and effective cleaning time through pulsed control, offering advantages such as high cleaning efficiency, low energy consumption, wide applicability, and strong controllability, making it suitable for cleaning and maintenance of various water supply pipelines.

Description

Technical Field

[0001] This invention relates to the field of water supply pipeline cleaning technology, and in particular to a pulse-type ice slurry cleaning method for water supply pipelines. Background Technology

[0002] Over long-term use, water supply pipes easily accumulate scale, rust, microbial films, and other impurities on their inner walls. These deposits not only reduce the flow area of ​​the pipes and decrease water supply efficiency, but may also pollute the water and endanger human health. Therefore, regular and effective cleaning of water supply pipes is a crucial step in ensuring water supply safety and stable system operation.

[0003] Ice slurry cleaning technology, as a green and efficient physical cleaning method, utilizes the shearing action and fluidity of ice slurry particles to remove deposits from the inner walls of pipes. It boasts advantages such as no chemical pollution, minimal damage to pipes, and excellent cleaning results, and has been increasingly applied in the field of water supply pipe cleaning. However, existing ice slurry cleaning technologies suffer from a core contradiction: currently, the most economical and efficient ice slurry volume, considered domestically and internationally, is 1 / 3 of the pipe volume. Using this parameter, if a high-velocity carrier fluid is used to propel the ice slurry within the pipe, while increasing the shearing force between the ice slurry and the pipe wall and enhancing deposit removal, it significantly shortens the residence time of the ice slurry within the pipe, resulting in insufficient effective cleaning time and limited cleaning effect on stubborn deposits. Conversely, if a low-velocity flow is used to propel the ice slurry, while extending the residence time and improving cleaning uniformity, the lower flow rate results in insufficient shearing force, failing to effectively remove firmly attached deposits, and similarly failing to achieve the desired cleaning effect.

[0004] To address the aforementioned contradictions, various optimization schemes have been attempted in related technical fields, such as adjusting the ice slurry concentration and changing the ice slurry particle size. However, none of these solutions have fundamentally reconciled the balance between shear force and effective cleaning time, and the cleaning efficiency and effect still need improvement. Therefore, developing an ice slurry cleaning method that can simultaneously consider shear force and effective cleaning time and significantly improve cleaning efficiency has become an urgent technical problem to be solved in the field of water supply pipeline cleaning. Summary of the Invention

[0005] To address the contradiction in existing ice slurry cleaning technologies for water supply pipelines—where high flow rates result in short effective cleaning times and low flow rates lead to insufficient shear force—this invention provides a pulse-type ice slurry cleaning method for water supply pipelines. By optimizing the pulse-type control of the carrier fluid velocity and the opening of the pipeline outlet valve, it achieves a synergistic improvement in shear force and effective cleaning time, thereby significantly enhancing the cleaning effect and increasing cleaning efficiency.

[0006] To achieve the above objectives, the present invention provides a method for pulse-type ice slurry cleaning of water supply pipelines, comprising the following steps: S1. Pipeline pretreatment: Check the sealing and unobstructedness of the water supply pipeline to be cleaned, close the irrelevant branch valves along the line, keep the inlet and outlet valves open, measure the pipeline length and inner diameter and calculate the pipeline volume. S2. High-concentration ice slurry injection: Inject a certain amount of high-concentration ice slurry into the pipe to be cleaned. S3, Pulsating fluid propulsion: After the ice slurry is injected, the fluid is injected into the pipeline. The pulse propulsion is achieved by controlling the opening of the outlet valve and the flow rate of the fluid at the inlet, including a cycle of valve-closing pressurization stage and valve-opening slow release stage. S4. Post-cleaning treatment: After the pulse-driven cleaning of the ice slurry is completed, the outlet valve is fully opened and the flow rate of the carrier fluid is increased to flush out the cleaning waste liquid and complete the cleaning process.

[0007] Preferably, in step S1, a pressure sensor and a flow monitor are respectively installed at the inlet and outlet ends to monitor the pressure and flow rate of the fluid in the pipeline in real time, and transmit the monitoring data to the central control system to automatically adjust the opening of the electric valve and the flow rate of the fluid.

[0008] Preferably, in step S2, the amount of ice slurry injected into the pipe is 1 / 3 of the volume of the pipe to be cleaned, the mass concentration of the high-concentration ice slurry is 30%-50%, and the particle size of the high-concentration ice slurry is 1mm.

[0009] Preferably, in step S3, the control parameters for the valve-closing pressurization stage are: the electric valve at the outlet is closed, the flow rate of the fluid at the inlet is controlled at 0.8-1.2 m / s, and the holding time is 1-2 s.

[0010] Preferably, in step S3, the control parameters for the valve opening and slow release stage are: the electric valve at the outlet is opened, the flow rate of the fluid at the inlet is controlled at 0.5 m / s, and the holding time is 2 s.

[0011] Preferably, in step S3, a single pulse cycle includes a valve-closing pressurization phase and a valve-opening slow-release phase, with a total duration of 3-4 seconds; the number of pulse cycles is 10-30 times, adjusted according to the degree of pipeline contamination and length.

[0012] Preferably, in step S3, the cleaning effect is verified by CFD numerical simulation, in which shear force monitoring points and flow velocity monitoring points are set to replace pressure sensors and flow meters.

[0013] Preferably, in step S4, when rinsing and discharging the cleaning waste liquid, the flow rate of the carrier fluid is >1m / s, and the rinsing time is 5-10min.

[0014] Preferably, in step S4, the method for determining whether the pipeline is clean is as follows: detect the turbidity of the waste liquid at the monitoring points along the pipeline, and when the turbidity is stable below 1 NTU, the pipeline is considered clean.

[0015] Preferably, in step S4, the method for determining that the cleaning waste liquid has been completely discharged is: detecting the conductivity of the waste liquid, and ending the entire rinsing process when the conductivity drops below 0.1.

[0016] Therefore, the pulse-type ice slurry cleaning method for water supply pipelines using the above-described structure has the following beneficial effects: (1) This invention achieves high flow rate and high shear force in the valve-closing pressurization stage to quickly remove stubborn deposits; and achieves low flow rate and long residence time in the valve-opening slow release stage. The pressure release accumulated in the pressurization stage can enhance the shear force in the slow release stage, ensuring sufficient cleaning. It successfully coordinates the balance between shear force and effective cleaning time, fundamentally improving the cleaning effect.

[0017] (2) The present invention reduces the energy consumption of the carrier fluid by using precise pulse control, without the need to maintain a high flow rate continuously, thus ensuring the cleaning effect. At the same time, the precise injection of high-concentration ice slurry (1 / 3 of the pipe volume) ensures the shearing capacity and avoids the waste of ice slurry, further improving the cleaning economy.

[0018] (3) The present invention can be adapted to water supply pipes of different diameters, lengths and pollution levels by adjusting the ice slurry concentration, pulse cycle number, flow rate parameters, etc. Whether it is a small urban tap water pipe or a large industrial water supply pipe, it can achieve the ideal cleaning effect.

[0019] (4) The present invention achieves automated and precise control of fluid velocity and valve opening through the synergistic effect of pressure sensor, flow rate sensor and central control system, reducing human operation error and improving the stability and reliability of the cleaning process.

[0020] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0021] Figure 1 A schematic diagram of the flow rate-valve combined control ice slurry cleaning process provided by the present invention; Figure 2 This is a schematic diagram of the pigging model provided by the present invention; Figure 3 The diagram showing the effect of flow rate on cleaning effect provided by this invention; Figure 4 The diagram showing the effect of valve closure on cleaning effect provided by this invention; Figure 5 Provided by the present invention t=3s, v max Simulation results of shear force at 0.8 m / s; Figure 6 Provided by the present invention t=4s, v max Simulation results of shear force at 0.8 m / s; Figure 7 Provided by the present invention t=3s, v max Simulation results of shear force at 1.0 m / s; Figure 8 Provided by the present invention t=4s, v max Simulation results of shear force at 1.0 m / s; Figure 9 Provided by the present invention t=3s, v max Simulation results of shear force at 1.2 m / s; Figure 10 Provided by the present invention t=4s, v max Simulation results of shear force at 1.2 m / s. Detailed Implementation

[0022] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0023] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "first," "second," and similar terms used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0024] Example This embodiment uses a city water supply pipe with a diameter of DN200 and a length of 20m (pipe volume ≈ 0.628m³). 3 This paper takes a numerical simulation case of pulsed ice slurry cleaning as an example to illustrate the point.

[0025] like Figure 1 and Figure 2 As shown, the present invention provides a method for pulse-type ice slurry cleaning of water supply pipelines, as detailed below: S1. Pipe Pretreatment: Measure the pipe length and inner diameter and calculate the pipe volume.

[0026] Based on actual pipe parameters of DN200 diameter and 20m length, a three-dimensional pipe model was constructed using ANSYS simulation software. Structured meshing was used, with mesh refinement applied to the pipe inner wall and the core region of the ice slurry flow. Boundary conditions were set as follows: the inlet was a velocity inlet, the outlet was a pressure outlet, the pipe inner wall was set as a no-slip boundary, the pipe inner diameter was 200mm, and the pipe volume was 0.628m³. 3 .

[0027] S2, High-concentration ice slurry injection: Define high-concentration ice slurry parameters in the simulation model.

[0028] A 5% sodium chloride solution with a density of 1038 kg / m³ was used. 3 The viscosity was set to 0.001153 Pa·s, and the ice particle density was set to 915 kg / m³. 3 The concentration was set to 30%, the ice slurry particle size was set to 1mm, and the ice slurry injection volume was set to 1 / 3 of the pipe volume, i.e., 0.209m³. 3 The actual ice slurry injection process is simulated by batch injection at the model inlet face.

[0029] S3, pulsed fluid-carrying propulsion.

[0030] After the ice slurry is injected, water is injected into the pipeline. The pulse-driven operation is achieved by controlling the outlet state and the inlet flow rate, including a cycle of valve-closing pressurization and valve-opening slow release.

[0031] Simulation of the valve-closing pressurization stage: Set the outlet valve to be closed, and increase the flow velocity of the inlet fluid to 0.8m / s, 1.0m / s, or 1.2m / s for 1s or 2s.

[0032] Simulation of the valve opening and slow release phase: The outlet valve is set to open, and the flow velocity of the inlet fluid is reduced to 0.5m / s for 2s; the single pulse cycle is 3s or 4s.

[0033] Cyclic pulse simulation: Set the pulse cycle to 10 times and start the simulation calculation; monitor the ice slurry flow state and shear force distribution in real time during the simulation.

[0034] S4. Post-cleaning treatment: After completing the pulse cycle, fully open the outlet valve and increase the flow rate of the carrier fluid to flush out the cleaning waste liquid, thus completing the cleaning process.

[0035] With the outlet valve fully open and the inlet fluid velocity increased to 1.2 m / s, continuous flushing was performed for 8 minutes. Simulation results showed that the cleaning waste liquid (ice slurry residue) in the pipeline could be completely discharged without adversely affecting the water quality of the pipeline network.

[0036] The effects of this invention will be analyzed in detail based on the simulation results: pass Figure 3 It can be observed that when the flow rate is 0.5 m / s, the maximum shear force of the ice slurry on the pipe wall is relatively small, only 3.7 Pa, and the effective cleaning time is about 13 s. When the flow rate is 0.8 m / s, the maximum cleaning effect of the ice slurry on the pipe wall is enhanced, but the effective cleaning time at the same location is shortened to 10.5 s. When the flow rate increases to 1.0 m / s, the maximum shear force of the ice slurry on the pipe wall increases to about 9.8 Pa, but the effective cleaning time at that location is shortened to 8.5 s. This indicates that traditional ice slurry cleaning faces a contradiction between effective cleaning time and maximum shear force.

[0037] pass Figure 4 It can be observed that although closing the valve can prolong the residence time of the ice slurry in the pipeline, the reduced flow rate and significantly decreased shearing effect after valve closure still make it difficult to effectively clean the pipeline. Therefore, simply closing the valve has limited effect on improving the cleaning effect and must be combined with pulsed flow rate control.

[0038] pass Figure 5 and Figure 6 It can be observed that in v max Under the condition of 0.8 m / s, when t = 3 s ( Figure 5 Pressure begins to accumulate inside the pipe, and the shear force increases; when t=4s ( Figure 6 As the valve closing time increases, the pressure accumulation becomes more pronounced, and the shear force further increases, but the overall shear force remains relatively low.

[0039] pass Figure 7 and Figure 8 It can be observed that in v max Under operating conditions of 1.0 m / s, the pulsed ice slurry cleaning strategy with combined flow rate and valve control is highly effective. For example... Figure 7 As shown, at t=3s, the higher inlet velocity causes the shear force to rise rapidly; as Figure 8 As shown, at t=4s, the average shear force between the ice slurry and the inner wall of the pipe can reach up to 5.5Pa, which is 44.7% higher than when the flow rate is constant at 0.5m / s. This can quickly remove deposits from the inner wall of the pipe, and the effective cleaning time is 12.5s, which is not significantly reduced compared to 13s when the flow rate is constant at 0.5m / s. This indicates that the strategy significantly improves the cleaning efficiency.

[0040] pass Figure 9 and Figure 10 It can be observed that in v max Under the condition of 1.2 m / s, the inlet velocity further increases. For example... Figure 9As shown, at t=3s, the rate of increase of shear force is significantly accelerated; as Figure 10 As shown, at t=4s, the average peak shear force continued to increase by about 0.5-1.0Pa compared to the 1.0m / s condition, indicating that a higher inlet flow velocity can significantly enhance the shearing effect in the pipeline and directly improve the flushing intensity.

[0041] In summary, under the same cycle time, v max Increasing the flow rate from 0.8 m / s to 1.0 m / s and 1.2 m / s increases the average peak shear force by approximately 0.5-2.0 Pa, with a faster rate of increase. At the same pressurized flow rate, increasing the circulation time (i.e., increasing the valve-closing time) allows for greater pressure accumulation, resulting in a slight increase in shear force during the valve-opening phase. Within the scope of this invention, the faster the flow rate and the longer the duration of the valve-closing pressurization phase, the greater the increase in shear force, verifying the effectiveness of the method.

[0042] Example 2 This embodiment is an engineering application case of the above-described pulsed ice slurry cleaning method for water supply pipelines in a real DN200 tap water pipeline. In the actual project, the automatic adjustment of claim 2 is implemented through the following hardware system: The central control system uses a Siemens S7-1200 PLC controller; the flow rate regulation of the inlet fluid is achieved by connecting the variable frequency water pump to the analog output terminal of the PLC; the opening degree regulation of the outlet electric valve is achieved by connecting an electric regulating valve (such as a pneumatically actuated regulating valve) with a full stroke time ≤ 1 second to the PLC.

[0043] In step S1, an electromagnetic flow meter and a pressure transmitter are installed at the water inlet, and their 4-20mA signals are connected to the analog input module of the PLC.

[0044] In the pulsed fluid-carrying stage of step S3, a timed interrupt program is written inside the PLC. Following a preset timing sequence (e.g., outputting a frequency signal corresponding to 0.8-1.2 m / s to the frequency converter for 1-2 seconds, simultaneously outputting a valve-closing signal to the electric regulating valve; then outputting a frequency signal corresponding to 0.5 m / s to the frequency converter for 2 seconds, and outputting a valve-opening signal), it achieves second-level automatic pulse cycle control. Simultaneously, the PLC reads the pressure sensor values ​​in real time. If the pipeline pressure exceeds the safety threshold, it automatically pauses the pulse and slightly opens the valve to release pressure, achieving closed-loop safety protection.

[0045] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for pulse-type ice slurry cleaning of water supply pipelines, characterized in that, Includes the following steps: S1. Pipeline pretreatment: Check the sealing and unobstructedness of the water supply pipeline to be cleaned, close the irrelevant branch valves along the line, keep the inlet and outlet valves open, measure the pipeline length and inner diameter and calculate the pipeline volume. S2. High-concentration ice slurry injection: Inject a certain amount of high-concentration ice slurry into the pipe to be cleaned. S3, Pulsating fluid propulsion: After the ice slurry is injected, the fluid is injected into the pipeline. The pulse propulsion is achieved by controlling the opening of the outlet valve and the flow rate of the fluid at the inlet, including a cycle of valve-closing pressurization stage and valve-opening slow release stage. S4. Post-cleaning treatment: After the pulse-driven cleaning of the ice slurry is completed, the outlet valve is fully opened and the flow rate of the carrier fluid is increased to flush out the cleaning waste liquid and complete the cleaning process.

2. The method for pulse-type ice slurry cleaning of water supply pipelines according to claim 1, characterized in that, In step S1, a pressure sensor and a flow monitor are respectively installed at the inlet and outlet ends to monitor the pressure and flow rate of the fluid in the pipeline in real time, and transmit the monitoring data to the central control system to automatically adjust the opening of the electric valve and the flow rate of the fluid.

3. The method for pulse-type ice slurry cleaning of water supply pipelines according to claim 1, characterized in that, In step S2, the amount of ice slurry injected into the pipe is 1 / 3 of the volume of the pipe to be cleaned, the mass concentration of the high-concentration ice slurry is 30%-50%, and the particle size of the high-concentration ice slurry is 1mm.

4. The method for pulse-type ice slurry cleaning of water supply pipelines according to claim 1, characterized in that, In step S3, the control parameters for the valve-closing pressurization stage are: the electric valve at the outlet is closed, the flow rate of the fluid at the inlet is controlled at 0.8-1.2 m / s, and the holding time is 1-2 s.

5. The method for pulse-type ice slurry cleaning of water supply pipelines according to claim 1, characterized in that, In step S3, the control parameters for the valve opening and slow release stage are: the electric valve at the outlet is opened, the flow rate of the carrier fluid at the inlet is controlled at 0.5 m / s, and the holding time is 2 s.

6. The method for pulse-type ice slurry cleaning of water supply pipelines according to claim 1, characterized in that, In step S3, a single pulse cycle includes a valve-closing pressurization phase and a valve-opening slow-release phase, with a total duration of 3-4 seconds; the number of pulse cycles is 10-30 times, adjusted according to the degree of pipeline contamination and length.

7. The method for pulse-type ice slurry cleaning of water supply pipelines according to claim 1, characterized in that, In step S3, the cleaning effect is verified by CFD numerical simulation. In the numerical simulation, shear force monitoring points and flow velocity monitoring points are set to replace pressure sensors and flow meters.

8. The method for pulse-type ice slurry cleaning of water supply pipelines according to claim 1, characterized in that, In step S4, when flushing and discharging the cleaning waste liquid, the flow rate of the carrier fluid is >1m / s, and the flushing time is 5-10min.

9. The method for pulse-type ice slurry cleaning of water supply pipelines according to claim 1, characterized in that, In step S4, the method for determining whether the pipeline is clean is as follows: detect the turbidity of the waste liquid at the pipeline outlet monitoring point. When the turbidity is stable below 1 NTU, the pipeline is considered clean.

10. The method for pulse-type ice slurry cleaning of water supply pipelines according to claim 1, characterized in that, In step S4, the method to determine that the cleaning waste liquid has been completely discharged is to detect the conductivity of the waste liquid. When the conductivity drops to below 0.1, the entire rinsing process ends.

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