A powder jet grouting pile backing system with air source reuse and airlock pulse feeding

Abstract

This utility model discloses a gas-lock pulse feeding backstage system for powder jet grouting, aiming to solve the vicious cycle of "pipe blockage-impact" caused by the dilemma of controlling intermittent air supply in economical single-air-source pulse conveying. This backstage system constructs an air supply structure with main and auxiliary air paths under a single air source. Its core innovation is "air source reuse": using the conveying tank itself as an auxiliary air source, during the intermittent period of the main conveying, airflow is drawn from the auxiliary path to maintain the powder suspended in the pipe at a critical state with minimal energy consumption, thus resolving the operational contradiction of difficulty in simultaneously maintaining pressure and ensuring material supply. This completely solves the pipe blockage problem of single-air-source pulse conveying without increasing additional power costs; and achieves high reliability and stability comparable to a dual-air-source system at the economic cost of a single air source, significantly improving the level of automation control and reliably ensuring overall stability, reliability, and intelligence under long-distance and deep working conditions.

Description

Technical Field

[0001] This utility model relates to the technical field of powder jet grouting construction equipment, and more specifically, to a powder jet grouting back-end system with air source reuse and airlock pulse feeding. Background Technology

[0002] As a highly efficient in-situ reinforcement method for soft soil foundations, the quality of powder-jet jet grouting piles is closely related to the precise and uniform injection of the powder, acting as a curing agent, into the soil. Therefore, a reliable and accurately metered powder supply system is a crucial prerequisite for the successful application of this technology. In traditional powder-jet jet grouting construction, the quantitative feeding stage presents a major technical bottleneck. The industry often uses mechanical devices such as rotary feeders, but the output of these devices is easily affected by factors such as material level, back pressure, powder characteristics, and mechanical wear, leading to significant deviations between the actual powder injection volume and the design value, making it difficult to meet the precise quantitative requirements of high-quality pile foundations.

[0003] To address the aforementioned challenges in material feeding accuracy, the applicant proposed an innovative airlock-type quantitative feeding solution in another patent application filed on the same filing date. This solution employs a dual-valve structure of "filling valve-quantitative chamber-injection valve," utilizing the principle of volumetric batch metering, achieving a significant breakthrough in feeding accuracy and successfully overcoming the inherent defects of traditional mechanical devices. This solution already meets the accuracy and reliability requirements of conventional construction teams.

[0004] However, a key trade-off exists when configuring a power source for this high-precision material feeding technology. Technically, a "dual air compressor" configuration—where one independent air supply unit provides constant pressure to the conveying tank, and another independent air supply unit provides strong power for pneumatic conveying—can perfectly resolve the contradiction in air volume distribution. However, this approach complicates the equipment configuration, and its purchase cost, energy consumption, transportation, installation, and maintenance costs increase significantly.

[0005] Therefore, a more economical option is to use a single-air compressor. However, to avoid the strong, continuous air supply causing excessively low total air pressure and thus interfering with the stable pressurization of the conveying tank, a pulse-type air supply strategy based on "intermittent opening and closing" of the main air supply pipe becomes a necessary choice. But in practice, this also brings a new operational contradiction that requires careful consideration:

[0006] Setting the interval between air supply cycles presents a dilemma. If the interval is set too short, while ensuring continuous powder spraying at the front end, the main air source (air tank) will not have enough time to recover pressure. This will cause the total air pressure to continuously decrease, resulting in low and unstable pressure within the delivery tank. Unstable tank pressure directly undermines the premise of airlock-type metering, causing fluctuations in the amount of powder injected into the metering chamber each time, leading to a loss of accuracy. Simultaneously, an excessively low initial pressure within the metering chamber will also result in weak subsequent outward spraying.

[0007] Conversely, if the intermittent time is set too long, although it can ensure the pressure recovery of the main air source, the excessively long interruption in air supply will, on the one hand, cause the powder spraying interval of the front-end drilling rig to be too long, directly affecting the uniformity of the finished pile body; on the other hand, and more fatally, the powder-air two-phase flow in the delivery pipeline will rapidly settle due to the prolonged loss of kinetic energy, especially in vertical or inclined riser sections, where it is extremely easy to accumulate and cause pipeline blockage accidents. In addition, in order to restart the material flow that has begun to settle, a very large air pressure and volume need to be provided instantaneously, which in turn puts a huge impact on the already strained single air source system, creating a vicious cycle.

[0008] Therefore, how to inherit the advantages of high-precision feeding of airlock type while avoiding the high cost of dual air compressor solution, and how to economically and effectively solve the vicious cycle of "pipe blockage-impact" and complex operation contradictions caused by powder sedimentation in single air compressor pulse conveying, is a technical problem that urgently needs to be solved in this field. Utility Model Content

[0009] The technical problem this utility model aims to solve is to provide a single-air-source power solution that combines economy and high reliability for the high-precision airlock quantitative feeding technology proposed by the applicant. As described in the background art, when this high-precision feeding technology is combined with an economical single-air-source configuration, its pulsed air supply strategy falls into a dilemma: if the intermittent time is shortened to ensure material supply, the pressure stability of the conveying tank will be sacrificed due to insufficient pressure of the main air source, thus affecting the feeding accuracy and spraying capability; conversely, if the intermittent time of air supply is extended to ensure the pressure recovery of the main air source, i.e., the air storage tank, it will not only face the risk of damage to the uniformity of the pile body, but also cause the powder in the conveying pipeline to settle due to loss of kinetic energy, thus triggering a vicious cycle of "pipe blockage-impact"—that is, restarting the suspended conveying state of the powder that tends to settle requires huge instantaneous air pressure (especially in the rising stage of the conveying pipeline), which in turn causes a huge impact on the already strained single-air-source system. Therefore, the core technical problem that this utility model aims to solve is: how to break through the operational bottleneck of the above-mentioned single gas source pulse gas supply on the basis of inheriting the advantages of high-precision material feeding of airlock type, and realize a truly stable and reliable single gas source transportation scheme that can both allow the main gas source, i.e. the gas storage tank, to have sufficient time to restore pressure and ensure smooth pipeline during the transportation interval.

[0010] To address the aforementioned problems, this invention provides a powder jet grouting pile back-end system and construction method featuring air-lock pulse feeding with air source reuse. The main objective of this invention is to propose an innovative system architecture and a phased, coordinated air supply control strategy. Its core lies in cleverly achieving "air source reuse" by adding an auxiliary air path: during the intervals of high-intensity pulse feeding in the main air path, the existing pressurized space of the conveying tank itself is used as an auxiliary air source, drawing out a small stream of auxiliary airflow to maintain the minimum energy required for the powder to remain suspended and flowing within the conveying pipeline. This invention aims to completely resolve the pipe blockage risks and operational contradictions of single-air-source pulse feeding without increasing additional power costs, through this innovative air source reuse strategy and the time-sharing design of the main and auxiliary air paths. It provides a technical solution for powder jet grouting pile construction that offers more precise material feeding, more reliable conveying, more intelligent control, and significant economic benefits.

[0011] A powder jet grouting support system with air-lock pulse feeding and air source reuse includes an air supply unit, a material feeding unit, a quantitative feeding unit, a pneumatic conveying unit, and a control unit for coordinating the operation of each unit. The output air path of the air supply unit is configured to provide a conveying air source to the pneumatic conveying unit and a pressurized air source to the material feeding unit. The material feeding unit includes a material tank body and a guide pipe connected to the outlet of the material tank body. The quantitative feeding unit is connected to the outlet of the guide pipe. The pneumatic conveying unit includes at least one air conveying pipe, a gas-solid mixing chamber, and a powder-air conveying pipe. The air inlet of each air conveying pipe is connected to the output air of the air supply unit. Along the way, air supply is achieved, with the outlet of each air supply pipe converging with the outlet of the quantitative feeding unit and connecting to the gas-solid mixing chamber. The control unit is configured to coordinate the opening and closing of the quantitative feeding unit to achieve pulse-type quantitative feeding. The inlet of the powder-gas conveying pipe is connected to the outlet of the gas-solid mixing chamber. One of the air supply pipes is connected to the conveying tank body by a conveying tank inlet pipe, forming a bidirectional air passage between the two to pressurize the conveying tank body or to transport the high-pressure gas in the conveying tank body in reverse through the conveying tank inlet pipe, the air supply pipe, and the gas-solid mixing chamber to the powder-gas conveying pipe. Through the "air source reuse" design, the output air path of the air supply unit provides power for pneumatic conveying and pressurizes the conveying tank. At the same time, the bidirectional air path formed by the conveying tank inlet pipe enables the high-pressure gas in the conveying tank to be transported in reverse to the powder-gas conveying pipe. By utilizing the high-pressure gas from the conveying tank itself as an auxiliary gas source, the gas is reversed and transported to the conveying pipe during the intermittent periods of the main gas path to maintain the powder suspension state. This fundamentally solves the problems of powder sedimentation and pipeline blockage caused by gas supply interruption in single-source pulse conveying. The bidirectional gas path design not only ensures the pressurization requirements of the conveying tank but also releases gas when the pressure is too high, avoiding the impact of tank pressure fluctuations on the subsequent quantitative feeding accuracy.

[0012] Preferably, a main air supply switch valve is installed on the output air path of the air supply unit; each air delivery pipe is equipped with an air delivery pipe switch valve. When the pneumatic conveying unit has a single air delivery pipe, the control unit is further configured to execute a phased coordinated air supply strategy. This strategy includes a main air delivery phase and an auxiliary air delivery phase, with both phases sharing a single air delivery pipe. The system switches between these two phases periodically or based on the system pressure status. In a single air delivery pipe scenario, by time-sharing the air delivery pipe, sufficient time is ensured for the main air source (air supply unit) to recover pressure (solving the problem of "continuously low main air source pressure" in the background technology), while the gas in the delivery tank maintains powder suspension, preventing sedimentation and pipe blockage. The main phase pulse delivery ensures the continuity of powder spraying at the front end, while the auxiliary phase utilizes the residual pressure in the delivery tank to maintain minimum suspension energy consumption, resolving the dilemma of "too short / too long intermittent time" (too short results in insufficient pressure, too long results in sedimentation and pipe blockage).

[0013] Preferably, a main gas path switching valve is provided on the output gas path of the gas supply unit; each gas delivery pipe is provided with a gas delivery pipe switching valve. When the pneumatic delivery unit has two gas delivery pipes, namely the first gas delivery pipe and the second gas delivery pipe, the gas delivery pipe switching valves are the first gas delivery pipe switching valve and the second gas delivery pipe switching valve. The control unit is further configured to execute a phased coordinated gas supply strategy, which includes a main gas path delivery stage and an auxiliary gas path delivery stage, and switches between these two stages periodically or according to the system pressure status. The main gas delivery pipe focuses on strong delivery, while the auxiliary gas delivery pipe focuses on suspension maintenance, avoiding pressure interference that may occur from time-sharing reuse of a single gas delivery pipe, allowing for more sufficient recovery of the main gas source pressure and more precise suspension control of the auxiliary gas path. The auxiliary gas delivery pipe only needs to provide the minimum gas volume to maintain suspension, which is more energy-efficient than the single gas delivery pipe mode; at the same time, the independent auxiliary gas path can respond to the risk of sedimentation more promptly, further reducing the probability of pipeline blockage.

[0014] Preferably, the quantitative feeding unit includes a filling valve, a metering chamber, and an injection valve connected in sequence. The inlet of the filling valve is connected to a guide pipe, and the outlet of the injection valve is connected to a gas-solid mixing chamber. The control unit is configured to coordinate the opening and closing actions of the filling valve and the injection valve to achieve pulsed quantitative feeding. The control unit is configured to periodically execute a quantitative feeding operation cycle including the following steps: During filling: the injection valve of the quantitative feeding unit is controlled to be closed, while the filling valve is opened, so that under the preset working pressure of the conveying tank body, the powder curing agent is filled from the conveying tank body through the guide pipe into the metering chamber with a predetermined volume until the predetermined injection conditions are reached; During injection: after the metering chamber is filled, the filling valve is controlled to be closed, and the injection valve is intermittently opened and closed once or multiple times according to the preset opening frequency and / or single opening duration parameters, so that the predetermined volume of powder curing agent stored in the metering chamber is pulsedly injected into the gas-solid mixing chamber of the pneumatic conveying unit under the pressure inside the metering chamber. By intermittently opening and closing the injection valve, the powder in the metering chamber is pulsedly sent into the gas-solid mixing chamber, matching the pulsed air source of the subsequent pneumatic conveying, ensuring uniform mixing of powder and gas, and improving conveying efficiency.

[0015] Preferably, the longitudinal profile of the guide tube in the vertical plane containing the central axis of the metering chamber includes, but is not limited to, a right-angled profile, a bull's horn profile, or any other smoothly transitioned curved shape; the internal flow channel of the metering chamber has a variable diameter structure, and the variable diameter structure includes, from inlet to outlet, an inlet expansion section connected to the outlet of the filling valve, an intermediate constant diameter metering section, and an outlet reduction section connected to the inlet of the injection valve. The smooth profile of the guide tube reduces the flow resistance of powder and avoids accumulation; the inlet expansion section of the metering chamber facilitates rapid filling, the intermediate constant diameter section ensures accurate metering volume, and the outlet reduction section enhances injection kinetic energy, reduces residue, and further improves metering accuracy and material discharge smoothness.

[0016] Preferably, the feeding unit further includes a support frame, a connecting flange, and a conveying tank exhaust pipe; the conveying tank body is mounted on the support frame, and the bottom of the conveying tank body is connected to the guide pipe via the connecting flange; a vibrator is installed at the bottom of the conveying tank body; the conveying tank exhaust pipe is connected to the top of the conveying tank body. The vibrator can break up powder "arching" or poor flow (especially for powders prone to agglomeration), ensuring sufficient filling of the metering chamber.

[0017] Preferably, the control unit includes a sensor group, a valve group, and a central control cabinet. The sensor group includes a weighing sensor for monitoring the weight of the powder curing agent inside the conveying tank and a conveying tank pressure gauge for monitoring the pressure inside the tank. The weight of the conveying tank body is supported by at least three weighing sensors, each of which is fixed to the support frame, and the conveying tank body is vertically pressed onto the weighing sensors. The conveying tank pressure gauge is mounted on the conveying tank body. The valve group includes a feed valve, a conveying tank pressurization valve, a conveying tank exhaust valve, and a main air circuit switch valve. The feed valve is mounted on the conveying tank body and is used to replenish the powder curing agent. The conveying tank pressurization valve is mounted on the conveying tank air inlet pipe, the conveying tank exhaust valve is mounted on the conveying tank exhaust pipe, and the main air circuit switch valve is mounted on the output air circuit. The central control cabinet is mounted on the support frame and is electrically connected to the vibrator, the valve group, the sensor group, and the quantitative feeding unit. Weighing sensors monitor the remaining powder in real time, pressure gauges control the pressure of the conveying tank, and the central control cabinet coordinates the actions of various components, improving the system's automation level, reducing manual intervention, and ensuring operational stability.

[0018] Preferably, the central axis of the gas delivery pipe intersects the central axis of the gas-solid mixing chamber, and the included angle is preferably less than 60°. The gas delivery pipe angle design and the variable diameter structure of the mixing chamber (accelerating airflow in the contraction section, fully mixing in the mixing section, and stable conveying in the divergence section) make the powder and gas mix more evenly and reduce conveying resistance.

[0019] Preferably, the gas-solid mixing chamber includes a variable diameter structure consisting of a contraction section at the inlet end, a mixing section in the middle, and a divergence section at the outlet end connected in sequence, wherein the cross-section of the contraction section is gradually narrowing, the mixing section is a straight pipe section with a constant cross-section, and the cross-section of the divergence section is gradually expanding.

[0020] Preferably, all gas delivery pipes are symmetrically distributed circumferentially along the gas-solid mixing chamber, or spaced apart axially along the gas-solid mixing chamber. This symmetrical / spaced distribution of the gas delivery pipes ensures uniform airflow distribution circumferentially within the mixing chamber, preventing localized powder accumulation due to airflow deviation and further reducing the risk of pipe blockage.

[0021] This utility model, by adopting a single air supply source configuration and innovatively designing an air source reuse system architecture, and matching a set of phased coordinated intelligent air supply control strategies, aims to achieve one or more of the following beneficial effects while inheriting the advantages of another patent filed by the applicant on the same application date: (i) Ensuring stable conveying and achieving efficient management of a single air source: The most significant advantage of this utility model is that, by using the conveying tank as an auxiliary air source during the interval of the main conveying pulse, a precisely controlled auxiliary airflow is added to the pipeline, maintaining the suspended flow of powder in the pipeline with minimal energy consumption, fundamentally solving the problem of sedimentation and pipe blockage in single-air-source pulse conveying. At the same time, through intelligent switching of the main and auxiliary air paths, the main air source is completely isolated from the air-consuming conveying pipeline, enabling it to quickly and efficiently restore pressure and reserve sufficient energy for the next main conveying pulse, perfectly resolving the power distribution contradiction of a single air source.

[0022] (II) Simplifying the system and reducing costs, while combining high reliability and economy: Compared with the dual gas source system, which requires two independent gas supply modules to operate without risk, this utility model achieves a transmission reliability comparable to or even surpassing that of the dual gas source system with the lowest hardware cost through its innovative single gas source reuse design. It significantly simplifies the equipment configuration, reduces initial investment and subsequent maintenance costs, and has significant economic benefits.

[0023] (III) Ensuring High-Precision Quantitative Feeding: This utility model fully inherits the advantages of the airlock-type quantitative feeding unit in another patent filed by the applicant on the same application date. Through batch filling and discharging of the quantitative cavity, highly consistent quantitative feeding between batches is achieved. Furthermore, due to more complete recovery of the main air source and more stable pressure in the conveying tank, the feeding accuracy of this utility model is further guaranteed.

[0024] (iv) Enhancing Automation and Intelligence: This utility model elevates the control logic from simple valve timing to a multi-stage intelligent switching based on multi-dimensional information feedback such as system pressure and valve status. The entire coordinated gas supply process is autonomously completed by the central control cabinet, which not only improves operational reliability but also enables the system to adaptively adjust according to actual working conditions, significantly improving the level of intelligence in construction. Attached Figure Description

[0025] Figure 1 This is a front view of the overall structure of Embodiment 1 of this utility model;

[0026] Figure 2 This is a rear view of the overall structure of Embodiment 1 of this utility model;

[0027] Figure 3 This is a schematic diagram of the gas supply unit structure according to Embodiment 1 of this utility model;

[0028] Figure 4 This is a schematic diagram of the material storage unit according to Embodiment 1 of this utility model;

[0029] Figure 5 This is a pneumatic conveying circuit diagram of Embodiment 1 of this utility model;

[0030] Figure 6 This is a schematic diagram of the quantitative feeding unit, mixing chamber, and gas delivery pipe structure of Embodiment 1 of this utility model;

[0031] Figure 7 This is a schematic diagram of the overall structure of the feeding unit according to Embodiment 1 of this utility model;

[0032] Figure 8 This is another view of the overall structure of the feeding unit according to Embodiment 1 of this utility model;

[0033] Figure 9 This is a top view of the overall structure of the feeding unit according to Embodiment 1 of this utility model;

[0034] Figure 10 This is a schematic diagram of the quantitative feeding unit structure according to Embodiment 1 of this utility model;

[0035] Figure 11 These are schematic diagrams illustrating the construction methods of Embodiments 1 and 2 of this utility model;

[0036] Figure 12 These are schematic diagrams illustrating the collaborative operation of Embodiments 1 and 2 of this utility model with the front end.

[0037] Figure 13 This is a schematic diagram of the quantitative feeding unit structure in Embodiment 3 of this utility model;

[0038] Figure 14This is a schematic diagram of the powder-gas injection assembly structure in Embodiment 4 of this utility model;

[0039] Figure 15 for Figure 14 Enlarged illustration at the circled area

[0040] Figure 16 This is a schematic diagram of the construction method of Embodiment 5 of this utility model. Detailed Implementation

[0041] To make the above-mentioned objectives, features and advantages of this utility model more apparent and understandable, the specific embodiments of this utility model will be described in detail below with reference to the accompanying drawings.

[0042] Example 1

[0043] like Figures 1-12 As shown, this utility model provides a powder jetting pile back-end system with air-source reuse and airlock-type pulse feeding, including an air supply unit 1, a material feeding unit 2, a quantitative feeding unit 6, a pneumatic conveying unit 3, a material storage unit 5, and a control unit 4 for coordinating the operation of each unit. The air supply unit 1 includes an air supply module consisting of an air compressor 11, an air storage tank 12, and a refrigerated dryer 13. The air dryer 13 has an inlet filter 141 at its inlet end and two outlet filters 142 at its outlet end to remove moisture and impurities from the compressed air. The output air path 304 of the air supply unit 1 is configured to provide a conveying air source to the pneumatic conveying unit 3 and a pressurized air source to the material feeding unit 2. The material feeding unit 2 includes a material conveying tank body 210 and a guide pipe 216 connected to the outlet of the material conveying tank body 210. Specifically, as shown... Figure 12As shown, in this embodiment, the longitudinal profile of the guide pipe 216 in the vertical plane including its own central axis is a bull's horn profile, which can reduce the flow resistance of powder and avoid powder blockage or uneven flow rate caused by abrupt changes in the flow channel, ensuring smooth conveying of powder from the feed tank to the metering chamber 62. The longitudinal profile shape can also be a right-angle profile or any other smoothly transitioned curved shape. The pneumatic conveying unit 3 includes at least one air conveying pipe 303 and a powder-air conveying pipe 31; in this embodiment, two air conveying pipes 303 are used, namely the first air conveying pipe 303.a and the second air conveying pipe 303.b. The inlet ends of the first gas supply pipe 303.a and the second gas supply pipe 303.b converge and connect to the output gas path 304 of the gas supply unit 1. A main gas path switch valve 418 is installed on the output gas path 304. The outlet ends of the first gas supply pipe 303.a and the second gas supply pipe 303.b converge with the outlet end of the guide pipe 216 to form a gas-solid mixing chamber 305. A pressure relief hole for depressurization is provided on the gas-solid mixing chamber 305 to facilitate further control of the internal pressure. A first gas supply pipe switch valve 419.a, controlled by the control unit 4, is installed on the first gas supply pipe 303.a, and a second gas supply pipe switch valve 419.b, also controlled by the control unit 4, is installed on the second gas supply pipe 303.b. One of the gas supply pipes 303 (the second gas supply pipe 303.b) is connected to the main body 210 of the material tank by a material tank inlet pipe 214. The inlet end of the material tank inlet pipe 214 is connected to the second gas supply pipe 303.b, and the outlet end of the material tank inlet pipe 214 is connected to the top of the main body 210 of the material tank. A material tank pressurization valve 413 is provided on the material tank inlet pipe 214. The inlet end of the powder-gas conveying pipe 31 is connected to the gas-solid mixing chamber 305, and the outlet end of the powder-gas conveying pipe 31 is connected to the piling machine 7. The quantitative feeding unit 6 includes a filling valve 61, a quantitative chamber 62 and an injection valve 63 connected in sequence. The inlet of the filling valve 61 is connected to the guide pipe 216, and the outlet of the injection valve 63 is connected to the gas-solid mixing chamber 305. The control unit 4 is configured to coordinate the opening and closing actions of the filling valve 61 and the injection valve 63 to achieve pulse quantitative feeding.

[0044] Control method for the backend of powder jet grouting pile with air-lock pulse feeding and air source reuse: Control unit 4 is further configured to execute a phased coordinated air supply strategy, which includes a main air path delivery stage and an auxiliary air path delivery stage, and switches between these two stages periodically or according to the system pressure status:

[0045] S1. During the main gas delivery stage: the control unit 4 controls the main gas circuit switch valve 418 to be in the open state and intermittently opens and closes the first gas delivery pipe switch valve 419.a to provide a pulsed main delivery gas source for high-speed delivery of the powder curing agent sprayed from the quantitative feeding unit 6.

[0046] S2. During the auxiliary gas delivery stage: when all of the following preset conditions are met: ① the first gas delivery pipe switch valve 419.a is in the closed state; ② the filling valve 61 of the quantitative feeding unit 6 is in the closed state; ③ the pressure inside the delivery tank body 210 is detected to be higher than a preset safety threshold.

[0047] S2, Control Unit 4 performs a set of linked operations, including: controlling the main gas circuit switch valve 418 to close, so as to isolate the gas supply unit 1 from the delivery pipeline, thereby enabling it to efficiently restore the pressure in the gas storage tank 12; and simultaneously controlling the material tank pressurization valve 413 to open and the second gas delivery pipe switch valve 419.b to pulse open and close, so as to draw pressurized gas from the material tank body 210 as an auxiliary gas source to maintain the suspension state of the powder curing agent in the powder gas delivery pipe 31, so as to prevent it from settling or clogging.

[0048] Specifically, pulsed gas supply is a common strategy for balancing transport energy consumption and gas source pressure recovery. However, during the "shutdown" interval of the main transport gas flow, this strategy causes powder in long pipelines to settle and accumulate due to loss of transport kinetic energy, especially in vertical or inclined riser sections, easily forming a high-density "dense-phase plug". This directly results in the system needing to overcome a starting pressure much higher than under normal transport conditions to push these nearly stationary plugs when the next pulse gas flow is turned on. This instantaneous high-pressure demand not only places a huge load on a single gas source, but also easily leads to complete pipeline blockage due to insufficient thrust, which is the core difficulty of this technical route. To solve this contradiction, through the aforementioned phased coordinated gas supply strategy, during the "auxiliary gas path transport stage" when the main gas flow is shut down, an auxiliary gas path (second gas pipe 303.b) is used to supplement the powder gas transport pipe 31 with a precisely controlled, low-flow "suspended" gas flow, using the transport tank body 210 itself as a pressure buffer. The purpose of this auxiliary airflow is not for long-distance transport, but to maintain the fluidization or suspension of powder within the pipeline with minimal air consumption, fundamentally preventing the formation of dense-phase material plugs. Thus, each start-up of the main transport airflow faces a low-resistance flow state that is easily accelerated, thereby ensuring the continuity and high reliability of the entire transport process.

[0049] Specifically, such as Figures 7-9As shown, the feeding unit 2 also includes a support frame 212, a connecting flange 211, a conveying tank exhaust pipe 215, a ladder, and a guide pipe unblocking hole 218. The conveying tank body 210 has a pressure vessel structure with a conical discharge structure at its lower end. The conveying tank body 210 is mounted on the support frame 212, and the bottom of the conveying tank body 210 is connected to the guide pipe 216 through the connecting flange 211. The guide pipe 216 is used to convey the powder to the gas-solid mixing chamber 305. The guide pipe unblocking hole 218 is connected to the guide pipe 216 to achieve an unblocking effect. The outer wall of the conveying tank body 210 is equipped with multiple vibrators 213, which ensure uniform powder conveying. The weight of the conveying tank body 210 is supported by three weighing sensors 401. The lower part of the weighing sensors is fixed to the support frame 212, and the upper part is connected to the outer wall of the conveying tank body 210. This connection method allows the conveying tank body 210 to have a certain degree of lateral freedom of movement while transmitting vertical loads, so as to ensure the accuracy of weighing measurement. The top of the conveying tank body 210 is equipped with a feed valve 411 for replenishing powder curing agent. The conveying tank exhaust pipe 215 is located at the top of the conveying tank body 210, and the conveying tank exhaust pipe 215 is equipped with a conveying tank exhaust valve 414. The top of the conveying tank body 210 is also equipped with a conveying tank safety valve 415 to ensure the safety of air pressure inside the tank. A ladder is located on one side of the support frame 212 for easy climbing and maintenance. Vibrator 213, weighing sensor 401, feed valve 411, conveying tank pressurization valve 413, conveying tank exhaust valve 414 and conveying tank safety valve 415 are all electrically connected to the central control cabinet 42 of control unit 4.

[0050] Specifically, such as Figure 3 and Figure 6As shown, the control unit 4 includes a sensor group, a valve group, and a central control cabinet 42; the sensor group 40 includes three weighing sensors 401 for monitoring the weight of the powder curing agent in the conveying tank body 210, a conveying tank pressure gauge 403 for monitoring the pressure in the conveying tank body 210, a gas tank pressure gauge 404 for the gas storage tank 12, and a main gas pipe pressure gauge 402 for monitoring the conveying pipeline; each weighing sensor 401 is fixed on the support frame 212, and the conveying tank body 210 is vertically pressed onto the weighing sensor 401, and the conveying tank pressure gauge 403 is installed on the conveying tank body 210; the gas tank pressure gauge 404 is installed on the top of the gas storage tank 12, and the main gas pipe pressure gauge 402 is installed in the output gas path 304 of the gas supply unit 1. The valve assembly includes a conveying tank pressurization valve 413 and a conveying tank exhaust valve 414, a feed valve 411, a storage tank discharge valve 416, a main air circuit switch valve 418, and an air supply pipe switch valve 419 for regulating the pressure of the conveying tank body 210. The feed valve 411 is located at the top center of the conveying tank body 210, the conveying tank pressurization valve 413 is located on the conveying tank air inlet pipe 214, the conveying tank exhaust valve 414 is located on the conveying tank exhaust pipe 215, the storage tank discharge valve 416 is located at the bottom of the storage tank 50 of the storage unit 5, the main air circuit switch valve 418 is located on the output air circuit 304 of the air supply unit 1, the output air circuit 304 is also equipped with a main air pipe manual valve 417, and the air supply pipe switch valve 419 is located on the air supply pipe 303.

[0051] The central control cabinet 42 is electrically connected to the valve assembly, sensor assembly, and the filling valve 61 and injection valve 63 of the quantitative feeding unit 6; the central control cabinet 42 is configured to periodically execute a quantitative feeding operation cycle including the following steps:

[0052] S1: Filling: The injection valve 63 of the quantitative feeding unit 6 is closed, while the filling valve 61 is opened, so that under the preset working pressure of the conveying tank body 210, the powder curing agent is drawn from the conveying tank body 210 through the guide...

[0053] The tube 216 is filled into the metering chamber 62 with a defined volume until the predetermined injection conditions are met;

[0054] S2: Injection: After the metering chamber 62 is filled, the filling valve 61 is closed, and the injection valve 63 is opened and closed once or multiple times according to the preset opening frequency and / or single opening duration parameters, so that the powder curing agent stored in the metering chamber 62 of the predetermined volume is pulsedly injected into the gas-solid mixing chamber 305 of the pneumatic conveying unit 3 under the pressure inside the metering chamber 62.

[0055] Specifically, such as Figure 5 As shown, the central axes of the two gas supply pipes 303 intersect the central axis of the gas-solid mixing chamber 305, and the included angle is less than 60°, preferably 30°.

[0056] Specifically, such as Figure 10 As shown, the internal flow channel of the metering chamber 62 of the metering unit 6 is a variable diameter structure connected in sequence. The variable diameter structure includes an inlet expansion section connected to the outlet of the filling valve 61, an intermediate equal diameter metering section connected downstream of the inlet expansion section, and an outlet reduction section connected downstream of the intermediate equal diameter metering section and connected to the inlet of the injection valve 63.

[0057] Specifically, the inlet expansion section helps reduce the flow velocity of the powder curing agent entering from the guide pipe 216, reducing impact and disturbance, allowing the powder to fill the entire metering cavity 62 more smoothly and densely, improving the accuracy and repeatability of single metering. The intermediate constant-diameter metering section provides a precise volume reference, ensuring the geometric consistency of the powder curing dosage for each batch. The outlet reduction section, at the moment the injection valve 63 opens, creates an acceleration and focusing effect on the powder curing agent prepared to be discharged under high pressure within the metering cavity 62, resulting in a high-speed material flow with more concentrated energy and better directionality. This Venturi effect or similar throat effect helps increase the injection velocity and initial kinetic energy of the powder, enhancing its penetration and initial dispersion performance in the downstream gas-solid mixing chamber 305, and may improve the cut-off performance of the injection valve 63, reducing powder curing agent dripping or residue. Compared to a simple constant-diameter metering cavity, this "expansion-constant-reduction" structure, by optimizing the internal flow field, is more conducive to achieving rapid, accurate, and efficient pulsed metering.

[0058] Specifically, such as Figure 7 As shown, the central control cabinet 42 of the control unit 4 is configured to dynamically control the opening and closing of the pressurizing valve 413 and the exhaust valve 414 of the conveying tank based on the pressure data fed back by the pressure gauge 403 of the conveying tank, so as to accurately maintain the pressure in the conveying tank body 210 within the preset working pressure range. This stable upstream pressure is intended to ensure that when the filling valve 61 opens according to the preset program to fill the metering chamber 62, the metering chamber 62 can obtain a consistent amount of powder curing agent and the same initial internal pressure each time. This ensures that in each spraying cycle in which the subsequent spraying valve 63 opens according to the preset program, the amount of powder curing agent sprayed from the metering chamber 62 is highly consistent, thereby achieving overall quantitative feeding.

[0059] Specifically, the central control cabinet 42 of the control unit 4 is further configured to, during or before filling the metering chamber 62 through the filling valve 61, activate the vibrator 213 on the outer wall of the conveying tank body 210 in a timely manner according to preset conditions or real-time monitoring of the flow state of the powder curing agent, so as to help the powder curing agent overcome potential arching or poor flow and ensure that it flows smoothly and quickly into the metering chamber 62.

[0060] Specifically, such as Figure 4As shown, the storage unit 5 includes a storage tank 50 and a feeding mechanism for conveying the powder curing agent from the storage tank 50 to the conveying tank body 210. The feeding mechanism includes a feeding auger 51 corresponding to the storage tank 50, an auger motor 52 for driving the feeding auger 51, and a wire rope 53 for fixing the auger motor 52. The storage tank 50 is provided with a storage tank discharge valve 416 at the bottom. The control unit 4 automatically controls the start and stop of the feeding mechanism and the opening and closing of the storage tank discharge valve 416 according to the signal of the weighing sensor 401 on the conveying tank body 210, so as to realize the automatic replenishment of material to the conveying tank body 210 on demand.

[0061] In this embodiment, combined with Figure 11 The paper also discloses a construction method for the powder jet grouting pile back-end system using the aforementioned air source reuse airlock pulse feeding system, including the following standard steps:

[0062] S1: Setting operating parameters: Set background operating parameters on the central control cabinet 42. The parameters include at least the following: the working cycle of the quantitative feeding unit 6, including the filling time of the quantitative chamber 62, the opening and closing frequency and / or single opening time of the injection valve 63, the preset working pressure of the conveying tank body 210, the switching conditions between the main air conveying stage and the auxiliary air conveying stage, such as the pressure threshold and time cycle of the air storage tank 12, the weight of the material to be fed into the conveying tank body 210, the opening and closing cycle of the first air conveying pipe switch valve 419.a, the minimum safe pressure threshold in the conveying tank body 210 required to open the second air conveying pipe switch valve 419.b, and the residual powder curing agent threshold for starting automatic replenishment to the conveying tank body 210.

[0063] S2: Initial feeding of the conveying tank: Close the pressurization valve 413 of the conveying tank, open the exhaust valve 414 of the conveying tank, and wait for the pressure gauge 403 of the conveying tank to show that its internal pressure is zero. Open the feed valve 411 at the top of the conveying tank body 210, and at the same time start the auger motor 52 connected to the corresponding storage tank 50 in the storage unit 5 and open the discharge valve 416 at the bottom of the storage tank 50 to transport the powder curing agent from the storage tank 50 to the conveying tank body 210. When the weight monitored by the weighing sensor 401 on the conveying tank assembly 21 reaches the set weight to be fed, close the discharge valve 416 of the storage tank, stop the auger motor 52, close the feed valve 411 and the exhaust valve 414 of the conveying tank in sequence.

[0064] S3: System Start-up, Pre-pressurization and Standby: Start the air supply unit 1, open the pressurization valve 413 of the conveying tank, pressurize the conveying tank body 210 to the preset working pressure, and the central control cabinet 42 dynamically maintains the pressure according to the feedback of the conveying tank pressure gauge 403; after receiving the ready signal sent by the front-end piling machine 7, the central control cabinet 42 enters the work standby state, opens the main air circuit switch valve 418, and the central control cabinet 42 starts the air supply pipe switch valve 419 to intermittently open and close according to the preset cycle, and the background enters the spraying standby state;

[0065] S4: Execute phased coordinated air supply: After receiving the start of spraying operation command from the front-end piling machine, the central control cabinet 42 automatically switches between the "main air supply stage" and the "auxiliary air supply stage" according to the preset control logic and real-time sensor feedback to achieve continuous quantitative supply. The specific phase operation is as follows:

[0066] (a) During the main gas delivery phase: The control unit controls the main gas supply valve 418 to be in the open state and intermittently opens and closes the first gas supply pipe valve 419.a to provide a pulsed main gas supply source.

[0067] Used for high-speed conveying of powder curing agent sprayed from the metering unit;

[0068] (b) During the auxiliary gas delivery stage: when all of the following preset conditions are met: ① the first gas delivery pipe switch valve 419.a is in the closed state; ② the filling valve 61 of the quantitative feeding unit is in the closed state; ③ the pressure inside the delivery tank is detected to be higher than a preset safety threshold.

[0069] The control unit performs a set of linked operations, including: controlling the main gas circuit switch valve 418 to close, so as to isolate the gas supply unit 1 from the delivery pipeline, thereby enabling it to efficiently restore the pressure in the gas storage tank;

[0070] Simultaneously, the pressurization valve 413 of the conveying tank is opened and the second gas pipeline switch valve 419.b is opened and closed in a pulse manner to draw pressurized gas from the conveying tank body 210 as an auxiliary gas source to maintain the suspension state of the powder curing agent in the powder gas conveying pipe 31, so as to prevent it from settling or clogging.

[0071] S5: Execute quantitative feeding cycle: After receiving the start spraying operation command from the front-end piling machine 7, the central control cabinet 42 of the control unit 4 drives the filling valve 61 and spraying valve 63 of the quantitative feeding unit 6 to periodically and coordinately open and close, repeating the quantitative feeding operation cycle to achieve continuous and quantitative powder supply to the front-end piling machine 7. This feeding operation includes the following steps:

[0072] (a) Filling: First, close the injection valve 63, then open the filling valve 61. Under the preset working pressure of the conveying tank body 210, the powder curing agent is filled from the conveying tank body 210 through the guide pipe 216 into the metering chamber 62 for the set filling time.

[0073] (b) Spraying: Then close the filling valve 61, and control the spraying valve 63 to open and close intermittently or open once according to the preset opening and closing frequency and / or single opening duration, so that the batch of powder curing agent in the metering chamber 62 is sprayed into the gas-solid mixing chamber 305 of the pneumatic conveying unit 3 under the pressure inside the metering chamber 62 and is fully mixed with the compressed air from the air conveying pipe 403 before being conveyed.

[0074] S6: On-demand replenishment of the conveying tank: During the quantitative feeding operation, the weight of the powder curing agent in the conveying tank body 210 is continuously monitored; when the weighing sensor 401 detects that the remaining amount of powder curing agent is lower than the powder curing agent remaining amount threshold set in step S1, the central control cabinet 42 sends a command to the front-end piling machine 7 to request to stop drilling and keep idling; after the front-end piling machine 7 responds and enters the idling state, the central control cabinet 42 pauses the quantitative feeding cycle, and then executes the feeding procedure of step S2 to the conveying tank body 210; after the feeding is completed, the background returns to the standby state and notifies the front-end piling machine 7 that the operation can be resumed;

[0075] S7: Single pile operation completed: When the operation completion instruction is received from the front-end pile driver 7, the central control cabinet 42 stops the quantitative feeding cycle, closes all valves, and completes the operation; while waiting for the front-end pile driver 7 to move and issue a new pile operation instruction, the operation process of steps S1 to S6 is repeated until all predetermined pile positions are constructed.

[0076] The advantages of this embodiment include: First, improved accuracy: airlock quantitative feeding + pressure closed-loop control solves the feeding deviation problem of traditional mechanical devices; Second, reliable anti-clogging: main and auxiliary dual air circuits provide time-sharing air supply, eliminating the risk of pipe blockage during intermittent periods, suitable for long-distance / deep conveying; Third, economical cost: single air source architecture + material conveying tank reuses auxiliary air source, avoiding the cost of adding an independent air supply unit; Fourth, high automation: sensor monitoring + intelligent control realize the full automation of feeding and replenishing processes, improving construction efficiency.

[0077] Example 2

[0078] like Figure 11 As shown in the figure, this embodiment aims to provide a background configuration with better gas-solid mixing effect. Its physical structure is shown in the figure, and the pneumatic conveying unit 3 includes a first gas delivery pipe 303.a and a second gas delivery pipe 303.b. Unlike the scheme in Embodiment 1, in this embodiment, both the first gas delivery pipe 303.a and the second gas delivery pipe 303.b serve as main gas delivery pipelines, used to provide symmetrical and powerful conveying airflow during the main conveying stage. Simultaneously, the auxiliary gas path shares the same physical pipeline with the second gas delivery pipe 303.b, and is time-division multiplexed through the control unit 4.

[0079] Control unit 4 is configured to execute a phased coordinated gas supply strategy that includes "symmetrical main delivery" and "single-path auxiliary suspension":

[0080] (a) Main gas delivery stage: The main gas delivery valve 418 is in the open state. At the same time, the first gas delivery pipe valve 419.a and the second gas delivery pipe valve 419.b) are synchronously and intermittently opened and closed according to the preset main delivery frequency. The two symmetrical airflows converge in the gas-solid mixing chamber 305 to form a stable and uniform flow field.

[0081] (b) Auxiliary gas path conveying stage: When both switching valves 419.a and 419.b of the main conveying stage are closed, and other preset conditions are met (such as the filling valve of the quantitative feeding unit being closed and the conveying tank pressure being sufficient), the control unit executes a linkage operation: First, the main gas path switching valve 418 is closed to isolate the main gas supply unit 1 from the conveying pipeline to quickly restore pressure. Then, the conveying tank pressurization valve 413 is opened to introduce the auxiliary gas source from the conveying tank into the passage where the second gas conveying pipe 303.b is located. At the same time, only the second gas conveying pipe switching valve 419.b is pulsed open and closed at a preset auxiliary gas supply frequency to draw out a small stream of air to maintain the critical suspension state of the powder in the pipeline.

[0082] The advantage of this embodiment is more uniform gas-solid mixing: The use of dual-path symmetrical main airflow creates a more balanced flow field within the gas-solid mixing chamber 305. This not only provides more abundant power for long-distance, deep conveying but also ensures more thorough and uniform mixing of powder and gas, reducing the risk of material accumulation on the pipe walls and improving conveying efficiency. By sharing pipes and valves with one of the main air paths, the need for a third independent auxiliary pipeline is avoided. This "two-in-one" design achieves the three logical functions of "dual main paths + auxiliary path" while maintaining the simple physical structure of the dual pipelines, effectively controlling manufacturing costs and system complexity.

[0083] Example 3

[0084] This embodiment (e.g.) Figure 13 The structure of the unit shown is largely similar to that of the embodiment, with the key difference being that the metering chamber 62 of the metering unit 6 in this embodiment is a straight tube with a constant diameter. This provides a simpler and more economical airlock-type metering solution that can also reliably fill and discharge powder, meeting the basic requirements for metering.

[0085] The detailed construction method of the construction backend in this embodiment is the same as or substantially the same as the implementation method described in Embodiment 1, and will not be repeated here.

[0086] Example 4

[0087] Embodiment 4 is another implementation of this utility model, such as... Figure 14 , 15As shown, the general structure of this embodiment is the same as that of Embodiment 1. The only difference is that, in order to achieve a better mixing effect, the gas-solid mixing chamber 305 adopts a variable diameter structure consisting of a contraction section 305.a at the inlet end, a uniform diameter mixing section 305.b in the middle, and a divergence section 305.c at the outlet end connected in sequence. The cross-section of the contraction section 305.a is gradually narrowing, the mixing section 305.b is a straight pipe section with a uniform cross-section, and the cross-section of the divergence section 305.c is gradually expanding.

[0088] Specifically, in this variable-diameter structure, the converging section 305.a at the inlet end increases the velocity of the gas-solid two-phase flow by reducing the flow area, enhancing the turbulence intensity and shear effect of the airflow, thereby effectively breaking up powder particle agglomerations and promoting their initial radial dispersion in the airflow. The subsequent equal-diameter mixing section 305.b provides the necessary length and time, allowing the powder particles initially dispersed in the converging section 305.a to be further fully mixed under continuous turbulence, achieving a high degree of macroscopic and microscopic uniformity. Finally, the diverging section 305.c at the outlet end gradually expands the flow area to reduce the velocity of the gas-solid two-phase flow, stabilize the flow pattern, and further refine the uniformity of particle distribution across the cross-section, while also contributing to stable transport in the subsequent powder-gas conveying pipe 31. This specific variable-diameter structure of the gas-solid mixing chamber 305, characterized by "contraction-accelerated premixing, equal-diameter full mixing, and divergence-stabilized homogenization," achieves more thorough and uniform mixing of the gas and solid phases than traditional equal-diameter straight pipes through the optimized combination and synergistic effect of each section's function. This ensures that the powder curing agent delivered to the front-end drilling rig has high dispersion and concentration consistency in the airflow, which is of great significance for improving the uniformity of spraying, ensuring the quality of the pile body and the stability of the entire construction process.

[0089] The detailed construction method of the construction backend in this embodiment is the same as or substantially the same as the implementation method described in Embodiment 1, and will not be repeated here.

[0090] Example 5

[0091] like Figure 16 As shown in the figure, this embodiment aims to provide a background configuration with the simplest structure and the highest economic efficiency. Its physical structure is shown in the figure. The pneumatic conveying unit 3 includes only a common air supply pipe 303 and an air supply pipe switching valve 419 installed on it. The common air supply pipe 303 is innovatively designed to undertake two different functions, "main air supply" and "auxiliary air supply", at different time periods.

[0092] Control unit 4 is configured to execute a phased coordinated gas supply strategy, which includes a main gas supply phase and an auxiliary gas supply phase, both phases sharing a single gas supply pipe 303, and switching between these two phases periodically or based on system pressure status:

[0093] S1: During the main gas delivery stage: Control unit 4 controls the gas supply unit 1 to be in the open state, and intermittently opens and closes the gas delivery pipe switch valve 419 according to the preset main delivery frequency to provide a pulsed main delivery gas source for high-speed delivery of the powder curing agent sprayed from the quantitative feeding unit 6.

[0094] S2: During the auxiliary gas delivery stage: When the gas delivery pipe switch valve 419 is in the intermittent gas supply shutdown period of the main gas delivery stage and when the pressure inside the material tank body 210 is detected to be higher than a preset safety threshold, the control unit 4 executes a set of linkage operations, including: firstly, shutting off the gas supply unit 1 to isolate the main gas supply unit 1 and restore its pressure; introducing the auxiliary gas source from the material tank body 210 into the shared gas delivery pipe 303 through the material tank inlet pipe 214; and then pulse-opening and closing the same gas delivery pipe switch valve 419 again at a preset auxiliary gas supply frequency to send out the auxiliary gas source to maintain the critical suspension state of the powder.

[0095] The advantage of this embodiment is that, compared to any multi-pipeline solution, its hardware configuration is the most streamlined, requiring only a single gas supply pipe and a corresponding switching valve. This significantly reduces manufacturing costs, installation complexity, and potential points of failure, making it the most cost-effective solution for achieving the "gas source reuse and anti-clogging" function. It gives the single gas supply pipe switching valve 419 a dual role: in the main gas supply stage, it is a powerful pulse valve; in the auxiliary gas supply stage, it transforms into a precise suspension control valve. This "one valve, multiple uses" design maximizes the utilization rate of individual components, achieving extreme structural simplification and economy.

[0096] In summary, the advantages of this utility model include the following:

[0097] First, high-precision quantitative feeding is achieved: an airlock quantitative feeding unit is adopted, which periodically coordinates the actions of the filling valve 61 and the injection 63 to fill and discharge the quantitative 62 with a predetermined volume in batches, thereby achieving highly consistent quantitative feeding between batches and overcoming the defects of inaccuracy and unevenness of traditional feeding methods.

[0098] Second, it ensures stable conveying and completely eliminates the risk of pipe blockage: The most significant advantage of this utility model is that by using the conveying tank body 210 as an auxiliary air source during the interval of the main conveying pulse, it provides a continuous, low-flow pressure-maintaining airflow to the conveying pipeline, effectively maintaining the suspension state of the powder in the pipe.

[0099] This fundamentally solves the problem of powder settling caused by airflow interruption in single-source pulse conveying.

[0100] The solution to pipe blockage has greatly improved the reliability and continuity of the system's transmission under harsh conditions such as long distances and large elevation differences.

[0101] Third, it achieves efficient power recovery and distribution: This invention achieves optimal management of a single gas source through intelligent switching between two stages: "main gas path delivery" and "auxiliary gas path delivery." During the auxiliary gas path delivery stage, the main gas source is completely isolated from the gas-consuming delivery pipeline via the main gas path switch valve 418, enabling rapid and efficient pressure recovery and reserving sufficient energy for the next main delivery pulse. This strategy of combining "preparation" and "deployment" perfectly resolves the power distribution contradictions under a single gas source configuration.

[0102] Fourth, it simplifies the system and reduces costs: Compared to dual-source systems that require two independent gas supply modules to solve the pipe blockage problem, this utility model, with its innovative single-source dual-path design, achieves delivery reliability comparable to or even surpasses that of dual-source systems at the lowest hardware cost. It significantly simplifies the equipment configuration, reduces initial investment and subsequent maintenance costs, and has significant economic benefits.

[0103] Fifth, enhancing automation and intelligence: This invention elevates the control logic from simple valve timing to a multi-stage intelligent switching system based on feedback from system pressure, valve status, and other multi-dimensional information. The entire coordinated gas supply process is autonomously completed by the central control cabinet, which not only improves operational reliability but also enables the system to adaptively adjust according to actual working conditions, significantly enhancing the level of intelligent operation.

[0104] Although the present invention has been disclosed above, its scope of protection is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention, and all such changes and modifications will fall within the protection scope of the present invention.

Claims

1. A powder jet grouting support system with air source reuse and airlock pulse feeding, characterized in that, The system includes an air supply unit (1), a material supply unit (2), a quantitative feeding unit (6), a pneumatic conveying unit (3), and a control unit (4) for coordinating the operation of each unit. The output air path of the air supply unit (1) is configured to provide a conveying air source to the pneumatic conveying unit (3) and a pressurized air source to the material supply unit (2). The material supply unit (2) includes a conveying tank body (210) and a guide pipe (216) connected to the outlet of the conveying tank body (210). The quantitative feeding unit (6) is connected to the outlet of the guide pipe (216). The pneumatic conveying unit (3) includes at least one air supply pipe (303), a gas-solid mixing chamber (305), and a powder-air conveying pipe (31). The air inlet of each air supply pipe (303) is connected to the output air path (304) of the air supply unit (1) to realize the air source delivery. The outlet of each gas pipe (303) is connected to the outlet of the metering unit (6) and then to the gas-solid mixing chamber (305). The control unit (4) is configured to coordinate the opening and closing of the metering unit (6) to achieve pulsed metering. The inlet of the powder-gas conveying pipe (31) is connected to the outlet of the gas-solid mixing chamber (305). One of the gas pipes (303) is connected to the conveying tank body (210) by a conveying tank inlet pipe (214). The conveying tank inlet pipe (214) forms a bidirectional gas passage between the two to pressurize the conveying tank body (210) or to transport the high-pressure gas in the conveying tank body (210) in reverse through the conveying tank inlet pipe (214), the gas pipe (303) and the gas-solid mixing chamber (305) to the powder-gas conveying pipe (31).

2. The powder jet grouting support system with air source reuse and airlock pulse feeding as described in claim 1, characterized in that, The gas supply unit (1) is provided with a main gas supply switch valve (418) on the output gas path (304); each gas supply pipe (303) is provided with a gas supply pipe switch valve (419). When the pneumatic delivery unit (3) is a single gas supply pipe (303), the control unit (4) is further configured to execute a phased coordinated gas supply strategy, which includes a main gas supply stage and an auxiliary gas supply stage. The two stages share a single gas supply pipe (303) and switch between the two stages periodically or according to the system pressure status.

3. The powder jet grouting support system with air source reuse and airlock pulse feeding as described in claim 1, characterized in that, The gas supply unit (1) is provided with a main gas supply switch valve (418) on the output gas path (304); each gas supply pipe (303) is provided with a gas supply pipe switch valve (419). When the pneumatic conveying unit (3) has two gas supply pipes (303), they are the first gas supply pipe (303.a) and the second gas supply pipe (303.b), respectively. The gas supply pipe switch valve (419) is the first gas supply pipe switch valve (419.a) provided on the first gas supply pipe (303.a) and the second gas supply pipe switch valve (419.b) provided on the second gas supply pipe (303.b); the control unit (4) is further configured to execute a phased coordinated gas supply strategy, which includes a main gas supply stage and an auxiliary gas supply stage, and switches between the two stages periodically or according to the system pressure state.

4. The powder jet grouting support system with air source reuse and airlock pulse feeding as described in claim 1, characterized in that, The quantitative feeding unit (6) includes a filling valve (61), a quantitative chamber (62) and an injection valve (63) connected in sequence. The inlet of the filling valve (61) is connected to the guide pipe (216), and the outlet of the injection valve (63) is connected to the gas-solid mixing chamber (305). The control unit (4) is configured to coordinate the opening and closing actions of the filling valve (61) and the injection valve (63) to achieve pulsed quantitative feeding. The control unit (4) is configured to periodically execute the quantitative feeding operation cycle.

5. The powder jet grouting support system with air source reuse and airlock pulse feeding as described in claim 4, characterized in that, The longitudinal profile shape of the guide tube (216) in the vertical plane containing the central axis of the metering chamber (62) includes, but is not limited to, a right-angle profile, a bull-horn profile, or a curve shape with any smooth transition; the internal flow channel of the metering chamber (62) is a variable diameter structure, and the variable diameter structure includes, from inlet to outlet, an inlet expansion section connected to the outlet of the filling valve (61), an intermediate equal diameter metering section, and an outlet reduction section connected to the inlet of the injection valve (63).

6. The powder jet grouting support system with air source reuse and airlock pulse feeding according to claim 4, characterized in that, The feeding unit (2) also includes a support frame (212), a connecting flange (211), and a conveying tank exhaust pipe (215); the conveying tank body (210) is mounted on the support frame (212), the bottom of the conveying tank body (210) is connected to the guide pipe (216) through the connecting flange (211), and a vibrator (213) is provided at the bottom of the conveying tank body (210); the conveying tank exhaust pipe (215) is connected to the top of the conveying tank body (210).

7. The powder jet grouting support system with air source reuse and airlock pulse feeding as described in claim 6, characterized in that, The control unit (4) includes a sensor group, a valve group, and a central control cabinet (42); the sensor group includes a weighing sensor (401) for monitoring the weight of the powder curing agent in the conveying tank body (210) and a conveying tank pressure gauge (403) for monitoring the pressure inside the tank. The weight of the conveying tank body (210) is supported by at least three weighing sensors (401), each weighing sensor (401) is fixed on the support frame (212), and the conveying tank body (210) is vertically pressed onto the weighing sensor (401). The conveying tank pressure gauge (403) is installed on the conveying tank body (210); the valve group includes a feed valve (41) 1) The feed tank pressurization valve (413), the feed tank exhaust valve (414), and the main air circuit switch valve (418); the feed valve (411) is installed on the feed tank body (210) and is used for replenishing the powder curing agent; the feed tank pressurization valve (413) is installed on the feed tank air inlet pipe (214); the feed tank exhaust valve (414) is installed on the feed tank exhaust pipe (215); the main air circuit switch valve (418) is installed on the output air circuit (304); the central control cabinet (42) is installed on the support frame (212); the central control cabinet (42) is electrically connected to the vibrator (213), valve group, sensor group and the quantitative feeding unit (6).

8. The powder jet grouting support system with air source reuse and airlock pulse feeding as described in claim 1, characterized in that, The central axis of the gas delivery pipe (303) intersects the central axis of the gas-solid mixing chamber (305), and the included angle is less than 60°.

9. The powder jet grouting support system with air source reuse and airlock pulse feeding according to claim 1, characterized in that, The gas-solid mixing chamber (305) includes a variable diameter structure consisting of a converging section (305.a) at the inlet end, a mixing section (305.b) in the middle, and a diverging section (305.c) at the outlet end connected in sequence. The converging section (305.a) has a gradually narrowing cross-section, the mixing section (305.b) is a straight pipe section with a constant cross-section, and the diverging section (305.c) has a gradually expanding cross-section.

10. The powder jet grouting support system with air source reuse and airlock pulse feeding according to claim 1, characterized in that, All gas delivery pipes (303) are symmetrically distributed circumferentially along the gas-solid mixing chamber (305), or spaced apart axially along the gas-solid mixing chamber (305).

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