Self-excited oscillating nozzle for pipe cleaning

Abstract

The utility model belongs to pipeline cleaning technical field especially, it relates to a kind of self-excitation oscillation nozzle for pipeline cleaning, including high-pressure pipeline and the cleaning device connected with it, mechanical rotating handle is equipped on winch, the cleaning device includes the jet nozzle of being located in the center and the booster pump export pipeline connection, still include the central righting mechanism of fixed jet nozzle, the device is by using self transport medium, the jet technology of combining self-vibration pulse and cavitation effect is used to solve the technical bottleneck of not being cleaned thoroughly in the use of existing nozzle.

Description

Technical Field

[0001] This utility model belongs to the field of pipeline cleaning technology, and in particular relates to a self-excited oscillation nozzle for pipeline cleaning. Background Technology

[0002] Pipeline transportation, with its advantages of continuity, stability, and low cost, has gradually become the main mode of transporting fluid media such as oil, natural gas, and carbon dioxide. As pipeline operating time increases, corrosion and impurity deposition within the pipeline lead to a gradual increase in transport resistance, severely impacting transport efficiency and increasing transportation costs. Therefore, efficient pipeline cleaning technology is crucial. Nozzle design is paramount in cleaning technology, and existing research has attempted to introduce physical methods such as jet oscillation and thermal diffusion to improve cleaning effectiveness. Self-excited pulse jets, as a novel enhanced cleaning method, possess high-frequency impact force, cavitation effect, and resonance effect, effectively separating the deposited layer from the substrate structure. This application aims to provide a self-excited oscillation nozzle with good performance. Utility Model Content

[0003] The purpose of this invention is to provide a self-excited oscillating nozzle for pipeline cleaning. By utilizing its own transport medium and combining self-oscillating pulse and cavitation effect jet technology, it solves the technical bottleneck of incomplete cleaning in existing nozzles during use.

[0004] To achieve the above objectives, the technical solution adopted by this utility model is as follows:

[0005] A self-excited oscillating nozzle for pipeline cleaning includes a high-pressure pipe coiled on a winch and a cleaning device. The winch is equipped with a mechanical rotating handle. The cleaning device includes a jet nozzle located at the center and connected to the outlet pipe of a booster pump, and also includes a centering and straightening mechanism to fix the jet nozzle. The arrangement of the nozzles in the cleaning device is a key aspect; the specific arrangement of the nozzles is described in [details omitted]. Figure 1The cleaning device is equipped with four rear-mounted Laval nozzles to provide forward driving force and four front-mounted circumferential Laval nozzles with oscillating chambers to form a self-excited pulse jet that rotates for cleaning. The oscillating chamber is the key structure for realizing the self-excited pulse jet. The working principle of the Laval nozzle is that compressed air in the convergent section accelerates the gas from subsonic to sonic speed; in the expansion section, the gas expands and further increases its speed, ultimately achieving supersonic speed. The design of the oscillating chamber is crucial for regulating the expansion and compression process and the thermodynamic process. The expansion and compression process and the thermodynamic process during the motion within the oscillating chamber determine the disturbance and feedback of the vortex structure. Adjusting the disturbance feedback achieves effective excitation and completes the formation of the self-excited oscillating pulse jet. During the cleaning process, the self-excited pulse jet impacts impurities on the inner wall of the pipe at high speed, with an impact force several times that of traditional cleaning methods, effectively stripping impurities adhering to the pipe wall. At the same time, because the self-excited jet can resonate with the impurities on the wall, it loosens the impurities, further enhancing the cleaning effect. Furthermore, during the process of the high-speed jet passing through the Laval nozzle and oscillating cavity to form a self-oscillating pulse jet, low-pressure cavitation regions are locally formed at the nozzle exit and near the wall surface, thereby inducing cavitation. Cavitation bubbles are rapidly generated and collapsed near the wall surface, releasing microjets and instantaneous high-pressure pulses, further enhancing the shearing and impact stripping effect on the deposited layer. The superposition of cavitation and self-oscillating pulses produces a synergistic enhancement mechanism, which not only improves the efficiency of impurity removal but also expands the cleaning range, showing significant advantages, especially in removing stubborn deposits such as thick scale and metal corrosion products.

[0006] Furthermore, the centering and straightening mechanism includes a ring-shaped support arm with multiple casters on its outer edge, and the ring-shaped support arm is fixedly connected to the central nozzle by multiple support rods.

[0007] Furthermore, the jet nozzle includes a connecting part connected to the outlet pipe of the booster pump and a front-end spraying part. The front end of the spraying part is provided with four circumferential nozzles evenly distributed along the circumference, and also includes four rear nozzles evenly arranged tangentially along the spraying part. The rear nozzles are located behind the circumferential nozzles and their spraying direction is opposite to the forward direction of the spraying part. The spraying direction of the circumferential nozzles is perpendicular to the center of the spraying part.

[0008] Furthermore, the circumferential nozzle is a Laval nozzle with an oscillating cavity, comprising an upstream Laval nozzle, a middle oscillating cavity, and a downstream Laval nozzle. The central axes of the upstream Laval nozzle, the middle oscillating cavity, and the downstream Laval nozzle coincide, and the inner diameter of the oscillating cavity is larger than the inlet inner diameter of the upstream Laval nozzle, and the inlet inner diameter of the upstream Laval nozzle is larger than the inlet inner diameter of the downstream Laval nozzle. The nozzle structural parameters directly determine the jet velocity, pulse frequency, and cleaning range. For the design of the self-excited oscillating nozzle, see [link to design details]. Figure 5Through this independently designed nozzle, a self-oscillating pulse jet can be formed. Based on simulation and experimental results, a reasonable combination of parameters such as the upstream nozzle throat diameter d, the upstream nozzle outlet diameter d2, the oscillation cavity length L, and the collision wall angle α is fundamental to achieving a high-frequency, high-amplitude self-oscillating pulse jet. Among these, the design of the oscillation cavity is crucial for modulating the pulse frequency. Figure 6 and Figure 7 A suitable cavity diameter ratio (L / d2) can enhance peak velocity and pulse amplitude. The optimal match between the upstream nozzle structure and the cavity diameter ratio is as follows: Figure 8 .

[0009] The advantages of this utility model are:

[0010] 1. For the first time, self-excited oscillating pulse jet technology is introduced into pipeline cleaning: forming a jet with high impact force, high frequency pulse, and cavitation effect, which can effectively remove stubborn deposits, such as carbonate crystals and rust.

[0011] 2. A cleaning device with a centering and straightening mechanism is designed to ensure that the cleaning nozzle is always located in the center of the pipeline, thereby improving energy efficiency and cleaning effect;

[0012] 3. Adopting a dedicated Laval nozzle and oscillation chamber combination structure: forming a stable self-excited oscillation structure, the jet has good supersonic characteristics, enhancing the jet energy transfer and impurity removal capabilities. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of a self-excited oscillating nozzle used for pipeline cleaning.

[0014] Figure 2 This is a schematic diagram of the axial cross-section of a self-excited oscillating nozzle used for pipeline cleaning.

[0015] Figure 3 This is a three-dimensional structural diagram of the radial cross-section of a self-excited oscillating nozzle used for pipeline cleaning.

[0016] Figure 4 This is a reference diagram showing the usage state of this utility model.

[0017] Figure 5 This is a design drawing of the circumferential nozzle in this utility model, wherein the upstream nozzle throat diameter is d; the upstream nozzle inlet diameter is d1; the upstream nozzle outlet diameter is d2; the oscillation chamber length is L; the oscillation chamber diameter is D; the collision wall angle is α; and the downstream nozzle inlet diameter is d3.

[0018] Figure 6 It is the frequency of the self-oscillating pulse jet under different oscillation cavity lengths when d2=2.5mm.

[0019] Figure 7It is the frequency of the self-oscillating pulse jet under different upstream nozzle outlet diameters when L=6mm.

[0020] Figure 8 This is a diagram showing the optimal ratio between the upstream nozzle structure and the cavity diameter. Detailed Implementation Example

[0021] like Figure 1-8 As shown, a self-excited oscillating nozzle for pipeline cleaning includes a winch and a cleaning device. The winch is equipped with a mechanical rotating handle. The cleaning device includes a jet nozzle 1 located at the center and connected to the outlet pipeline of a booster pump, and a centering and straightening mechanism 2 for fixing the jet nozzle. The arrangement of the nozzles in the cleaning device is a key aspect; the specific arrangement of the nozzles is shown in [details omitted]. Figure 1The cleaning device is equipped with four rear-mounted Laval nozzles to provide forward driving force and four front-mounted circumferential Laval nozzles with oscillating chambers to form a self-excited pulse jet that rotates for cleaning. The oscillating chamber is the key structure for realizing the self-excited pulse jet. The working principle of the Laval nozzle is that compressed air in the convergent section accelerates the gas from subsonic to sonic speed; in the expansion section, the gas expands and further increases its speed, ultimately achieving supersonic speed. The design of the oscillating chamber is crucial for regulating the expansion and compression process and the thermodynamic process. The expansion and compression process and the thermodynamic process during the motion within the oscillating chamber determine the disturbance and feedback of the vortex structure. Adjusting the disturbance feedback achieves effective excitation and completes the formation of the self-excited oscillating pulse jet. During the cleaning process, the self-excited pulse jet impacts impurities on the inner wall of the pipe at high speed, with an impact force several times that of traditional cleaning methods, effectively stripping impurities adhering to the pipe wall. At the same time, because the self-excited jet can resonate with the impurities on the wall, it loosens the impurities, further enhancing the cleaning effect. Furthermore, during the process of the high-speed jet forming a self-oscillating pulse jet through the Laval nozzle and oscillating cavity, low-pressure cavitation regions are formed locally at the nozzle outlet and near the wall surface, thereby inducing cavitation effects. Cavitation bubbles are rapidly generated and collapsed near the wall surface, releasing micro-jet streams and instantaneous high-pressure pulses, further enhancing the shearing and impact stripping effect on the deposited layer. The superposition of cavitation and self-oscillating pulses produces a synergistic strengthening mechanism, which not only improves the efficiency of impurity removal but also expands the cleaning range, especially showing significant advantages in removing stubborn deposits such as thick scale layers and metal corrosion products; the centering and straightening mechanism includes an annular support arm 5, with multiple universal wheels on the outer edge of the annular support arm, and the annular support arm is fixedly connected to the central jet nozzle by multiple support rods; the jet nozzle 1 includes a connecting part 11 connected to the outlet pipeline of the booster pump and a front-end spray part 12, the front end of the spray part is provided with four circumferential nozzles 3 evenly distributed along the circumference, and also includes four rear nozzles 4 evenly arranged tangentially along the spray part, the rear... The nozzle is positioned behind the circumferential nozzle, and its spray direction is opposite to the forward direction of the spray section. The spray direction of the circumferential nozzle is perpendicular to the center of the spray section. The circumferential nozzle is a Laval nozzle with an oscillating cavity, and its structure includes an upstream Laval nozzle, a middle oscillating cavity, and a downstream Laval nozzle. The central axes of the upstream Laval nozzle, the middle oscillating cavity, and the downstream Laval nozzle coincide, and the inner diameter of the oscillating cavity is larger than the inlet inner diameter of the upstream Laval nozzle, and the inlet inner diameter of the upstream Laval nozzle is larger than the inlet inner diameter of the downstream Laval nozzle. The nozzle structural parameters directly determine the jet velocity, pulse frequency, and cleaning range. The design of the self-excited oscillating nozzle, i.e., the jet nozzle, is described in [reference needed]. Figure 1Through this independently designed nozzle, a self-oscillating pulse jet can be formed. Based on simulation and experimental results, a reasonable combination of parameters such as the upstream nozzle throat diameter d, the upstream nozzle outlet diameter d2, the oscillation cavity length L, and the collision wall angle α is fundamental to achieving a high-frequency, high-amplitude self-oscillating pulse jet. Among these, the design of the oscillation cavity is crucial for modulating the pulse frequency. Figure 6 and Figure 7 A suitable cavity diameter ratio (L / d2) can enhance peak velocity and pulse amplitude. The optimal match between the upstream nozzle structure and the cavity diameter ratio is as follows: Figure 8 ;

[0022] Application examples

[0023] The following will detail the specific application process of the self-excited oscillation nozzle for pipeline cleaning according to this utility model, taking a carbon dioxide transport pipeline as an example.

[0024] Preliminary preparations: Before cleaning, conduct a comprehensive inspection of the carbon dioxide transport pipeline, including the integrity of the pipeline and the sealing of the valves. Connect the self-vibrating pulse jet cleaning device according to the drawings and design requirements, ensuring that the connection between the jet generator and the pipeline is well sealed. Inject low-pressure gas into the system and check for leaks at all connection points to ensure that no leaks occur under the high-pressure environment of carbon dioxide.

[0025] System startup and cleaning operation: Push the entire cleaning device into the transport pipeline to be cleaned.

[0026] The carbon dioxide supply system is activated to extract carbon dioxide from the carbon dioxide transport pipeline. The carbon dioxide passes through the cleaning pipeline and the winch to reach the cleaning device. Four self-vibrating pulse jets of carbon dioxide are formed at the circumferential nozzle 6, and a continuous jet of carbon dioxide is formed at the rear nozzle 7.

[0027] Cleaning Effect Monitoring: During the cleaning process, pipeline inspection equipment is used to monitor the cleaning effect. For example, a pipeline endoscope is used every hour to check the cleanliness of the inner wall of the pipeline, and images before and after cleaning are compared to determine the removal of dirt. If a large amount of dirt remains, the jet pressure is adjusted to enhance the cleaning ability of the jet. In the actual cleaning process, the system achieves a dual-enhanced cleaning mechanism by utilizing high-frequency pulsed jets and the local cavitation phenomenon at the Laval nozzle outlet. Cavitation bubbles induced by high-speed airflow collapse near the wall surface, instantly converting local kinetic energy into high-frequency impacts, resulting in a stronger scouring, shearing, and stripping effect on the attached scale and deposits. Experimental verification shows that, under the same pressure conditions, the self-oscillating pulsed jet with superimposed cavitation effect has a significantly better cleaning depth and area than the simple self-oscillating jet.

[0028] Post-cleaning treatment:

[0029] Once the in-pipe detection system detects that the cleaning device has completed its cleaning operation, the booster pump, temperature control device, and pressure sensor are turned off. The cleaning device is then pulled by rotating the winch using the handle, and the cleaning device is removed to complete the cleaning operation. At the same time, the cleaning device is maintained and serviced, and the wear and tear of each piece of equipment is checked. Wear-prone parts such as shut-off valves, pressure relief valves, and ball valves are replaced to prepare for the next cleaning operation.

Claims

1. A self-excited oscillating nozzle for pipeline cleaning, characterized in that: It includes a high-pressure pipeline and a cleaning device connected thereto. The winch is equipped with a mechanical rotating handle. The cleaning device includes a jet nozzle located at the center and connected to the outlet pipeline of the booster pump, and also includes a centering and straightening mechanism for fixing the jet nozzle.

2. The self-excited oscillating nozzle for pipeline cleaning as described in claim 1, characterized in that: The centering and straightening mechanism includes a ring-shaped support arm with multiple casters on its outer edge. The ring-shaped support arm is fixedly connected to the central nozzle by multiple support rods.

3. The self-excited oscillating nozzle for pipeline cleaning as described in claim 2, characterized in that: The jet nozzle includes a connecting part connected to the outlet pipe of the booster pump and a front-end spraying part. The front end of the spraying part is provided with four circumferential nozzles evenly distributed along the circumference, and also includes four rear nozzles evenly arranged tangentially along the spraying part. The rear nozzles are located behind the circumferential nozzles and their spraying direction is opposite to the forward direction of the spraying part. The spraying direction of the circumferential nozzles is perpendicular to the center of the spraying part.

4. The self-excited oscillating nozzle for pipeline cleaning as described in claim 3, characterized in that: The circumferential nozzle is a Laval nozzle with an oscillating cavity. The structure includes an upstream Laval nozzle, a middle oscillating cavity, and a downstream Laval nozzle. The central axes of the upstream Laval nozzle, the middle oscillating cavity, and the downstream Laval nozzle coincide, and the inner diameter of the oscillating cavity is larger than the inlet inner diameter of the upstream Laval nozzle, and the inlet inner diameter of the upstream Laval nozzle is larger than the inlet inner diameter of the downstream Laval nozzle.

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