A multi-channel parallel airlock quantitative feeding powder jet grouting backstage

Abstract

This invention discloses a multi-channel parallel airlock quantitative feeding system for jet grouting piles, aiming to solve the technical problems of intermittent supply, limited peak flow, and poor durability under high-frequency operation caused by the inherent "filling-jetting" sequential operation mode of existing single-channel airlock feeding systems. Through at least two parallel quantitative feeding units, the control unit is configured to execute an alternating cooperative control strategy: when any quantitative feeding unit performs the jetting step, at least one other quantitative feeding unit simultaneously performs its filling preparation step. Through this multi-channel seamless switching cooperative working mode, this invention fundamentally innovates the pulsed intermittent supply into a stable, continuous quantitative supply. This not only significantly improves the uniformity of pile quality and construction continuity but also multiplies the system's supply flow limit and enhances operational reliability due to fault redundancy capabilities, resulting in significant technical and economic benefits.

Description

Technical Field

[0001] This utility model relates to the technical field of powder jet grouting construction equipment, and more specifically, to a multi-channel parallel airlock quantitative feeding powder jet grouting back-end system. Background Technology

[0002] In powder jet grouting projects, the accuracy, stability, and reliability of the back-end supply system in supplying curing agent powder are crucial to the final project quality. Traditional feeding devices (such as rotary feeders and screw conveyors) generally suffer from technical bottlenecks such as low quantitative accuracy, susceptibility to back pressure fluctuations during conveying, and easy pipe blockage during long-distance conveying.

[0003] To address the aforementioned fundamental issues, another patent document submitted by the applicant on the same day, titled "A Pneumatic Lock Pulse Feeding System for Powder Jetting Piles and its Construction Method," proposes an innovative single-channel pneumatic lock quantitative feeding system. This system achieves high-precision batch quantitative feeding through the precise coordination of the "filling valve - quantitative chamber - injection valve." This single-channel system effectively meets the accuracy and reliability requirements of conventional construction.

[0004] However, after in-depth research, the applicant discovered that due to its working principle, the single-path system has a fundamental limitation in its operating mode: its two core actions, "filling" and "jetting," are sequential and mutually exclusive. During the entire cycle of filling the metering chamber with powder, the system cannot perform any external jetting operations. This operating mode inevitably results in a pulsed and intermittent supply of powder. This directly leads to significant periodic fluctuations in the distribution of the curing agent along the length of the pile. Specifically, during the jetting stage, the soil at the corresponding depth receives sufficient curing agent; however, in the subsequent filling (no supply) stage, although the drilling and mixing action of the drill bit cause some powder to move up and down with the mixed soil, the newly added curing agent within this depth range is zero, and its local average content is inevitably lower than that formed in the jetting stage. This alternation of "peaks" and "troughs" in powder content along the pile length disrupts the overall uniformity of the pile, thus affecting the stability and consistency of its mechanical properties. Under conditions such as excessively long filling time and rapid drilling speed, the content at the "trough" may even be lower than the design value. Therefore, achieving uninterrupted continuous supply is a key prerequisite for obtaining uniform and high-quality pile foundations.

[0005] Furthermore, the limited flow rate of powder supply in a single-path system fundamentally restricts its applicability when dealing with large-diameter piles and high-dosage conditions. Meanwhile, the durability of the equipment under high-frequency operating modes of the control valves corresponding to high flow rates is also a technical bottleneck that the applicant aims to overcome in anticipation of future higher demands.

[0006] Therefore, as a further development and improvement of the aforementioned single-channel feeding technology, this utility model aims to provide a parallel multi-channel, alternating continuous quantitative feeding system. By setting up two sets of parallel and alternating quantitative feeding units, this utility model, while fully inheriting the core advantages of the single-channel system such as high precision and anti-clogging, aims to completely eliminate supply intermittency and significantly improve the system's peak flow rate and operational redundancy. This perfectly meets the highest standard of construction requirements, providing the industry with a superior, more reliable, and more economical ultimate solution. Utility Model Content

[0007] The technical problem this invention aims to solve is to overcome the intermittent supply caused by the sequential working mode of a high-precision, anti-clogging single-channel airlock quantitative feeding system, and to break through the application limitations resulting from it. Although a single-channel system can meet the needs of conventional construction, its "filling" and "spraying" actions are mutually exclusive, meaning that spraying cannot occur during filling, which inevitably makes the supply pulsed. When facing high-standard construction, this intermittent supply may not only affect the continuous uniformity of pile quality, but also limit the system's peak flow rate and the equipment's durability under extreme working conditions. At the same time, single-point failure mode also affects the fault tolerance rate of the operation. Therefore, the core technical problem that this invention aims to solve is: how to achieve truly uninterrupted continuous quantitative supply while inheriting the advantages of high-precision quantitative feeding and high-reliability delivery, and simultaneously improve the system's flow rate limit and operational reliability.

[0008] To address the aforementioned problems, this invention provides a multi-channel parallel airlock quantitative feeding system for powder jet grouting. The main objective of this invention is to propose an innovative multi-channel parallel feeding unit and a matching coordinated control strategy, thereby transforming intermittent pulsed supply into uninterrupted continuous supply. Its core lies in setting up at least two sets of parallel, structurally identical airlock quantitative feeding branches, and through intelligent scheduling by the control unit, enabling them to alternately operate in a "one-channel spraying, one-channel preparation" cycle. When the first channel is spraying, the second channel simultaneously fills and prepares; when the first channel finishes spraying, the second channel seamlessly takes over and begins spraying, while the first channel enters the filling state. This invention aims to fundamentally eliminate the feeding interval without altering the high-reliability backend conveying system through this ingenious multi-channel collaborative and seamless switching design, providing a final technical solution for powder jet grouting with a larger flow rate, more stable supply, and significantly enhanced reliability and economy.

[0009] To achieve the above objectives, this utility model provides a multi-channel parallel airlock quantitative feeding powder spraying pile back-end, including an air supply unit, a material supply 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 supply unit. The outlet of the material supply unit is connected to at least two diversion pipes. The outlet of each diversion pipe is connected to a quantitative feeding unit. The outlet ends of all quantitative feeding units and the air outlet ends of the pneumatic conveying units converge to form a gas-solid mixing chamber. Each quantitative feeding unit includes a filling valve, a metering chamber, and an injection valve in sequence along the material flow direction. The inlet of the filling valve is connected to the outlet of the material supply unit. The outlet of the injection valve is connected to the gas-solid mixing chamber. The control unit is configured to coordinate and control the operation of at least two quantitative feeding units to achieve an alternating cyclic working mode, thereby achieving continuous quantitative supply to the pneumatic conveying unit. This backend system enables continuous quantitative supply of powder, overcoming the intermittent supply caused by the sequential execution of "filling" and "spraying" in single-path systems. It avoids large periodic fluctuations in the distribution of the hardener in the pile body, ensuring the overall uniformity and stable mechanical properties of the pile. It significantly improves the system's peak flow rate and operational redundancy, enhancing its applicability to large-diameter piles and high-dosage conditions. Inheriting the core advantages of high precision and anti-clogging pipes from single-path airlock quantitative feeding systems, it also improves system reliability, reduces the impact of single-point failures on operations, increases operational tolerance, and offers superior overall performance, combining better reliability and economy.

[0010] Preferably, the pneumatic conveying unit includes a powder-air injection assembly, which includes a main air pipe connected to the air supply unit and at least one air delivery pipe. The inlet end of the air delivery pipe is connected to the main air pipe, and a main air circuit switch valve is installed on the main air pipe. The outlet end of the air delivery pipe and the outlet ends of all the branch pipes converge to form the gas-solid mixing chamber. An air delivery pipe switch valve controlled by the control unit is installed on the air delivery pipe. The structural design of the pneumatic conveying unit provides a stable air source for powder conveying, ensuring the smooth flow of powder in the supply unit. Furthermore, the air delivery state can be flexibly adjusted by the control unit through the air delivery pipe switch valve, coordinating with the operation of the quantitative feeding unit to ensure the stability and reliability of the gas-solid mixing and conveying process, thereby improving the overall coordination and controllability of the system.

[0011] Preferably, the central axis of each gas delivery pipe intersects the central axis of the gas-solid mixing chamber, and the included angle is preferably less than 60°. This angle design between the gas delivery pipe and the gas-solid mixing chamber facilitates thorough mixing of the airflow and powder, improving the gas-solid mixing efficiency and uniformity.

[0012] Preferably, when there are multiple gas delivery pipes, 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 distribution design of the gas delivery pipes and the gas-solid mixing chamber facilitates thorough mixing of the airflow and powder, improving gas-solid mixing efficiency and uniformity.

[0013] Preferably, the feeding unit is connected to the air supply unit via an air inlet pipe from the feeding tank to achieve pressurized air supply. The air inlet end of the air inlet pipe from the feeding tank is connected to one of the air supply pipes, and the air outlet end of the air inlet pipe from the feeding tank is connected to the feeding unit. This connection method using the air inlet pipe from the feeding tank can efficiently provide a pressurized air source to the feeding unit, ensuring the smooth flow of powder within the feeding unit.

[0014] Preferably, the feeding unit includes a conveying tank body, a support frame, a connecting flange, a guide pipe, and a conveying tank exhaust pipe. The conveying tank body is mounted on the support frame, and its bottom is connected to the guide pipe via the connecting flange. At least one vibrator is located at the bottom of the conveying tank body. The exhaust pipe is connected to the top of the conveying tank body. This structure provides a stable foundation for the storage and conveying of powder. The vibrator at the bottom of the conveying tank effectively solves the problems of powder arching or poor flow, ensuring that the powder can smoothly enter the guide pipe and guaranteeing the filling efficiency and stability of the subsequent quantitative feeding unit.

[0015] Preferably, the control unit includes a sensor group, a valve group, and a central control cabinet. The sensor group includes a load cell for monitoring the weight of the powder curing agent inside the conveying tank and a pressure gauge for monitoring the pressure inside the tank. The weight of the conveying tank is supported by at least three load cells, each of which is fixed to the support frame, and the conveying tank is vertically pressed onto the load cells. The pressure gauge is mounted on the conveying tank. The valve group includes a feed valve, a pressurization valve, and an exhaust valve. The feed valve is mounted on the conveying tank and is used to replenish the powder curing agent. The pressurization valve is mounted on the air inlet pipe of the conveying tank. The exhaust valve is mounted on the exhaust pipe of the conveying tank. The central control cabinet is mounted on the support frame and is electrically connected to the vibrator, valve group, sensor group, and quantitative feeding unit. The electrical connection between the central control cabinet and each component enables centralized control and coordinated operation of the system, improving the system's automation level and operational reliability.

[0016] Preferably, the longitudinal profile of the guide tube in the vertical plane containing the central axis of the metering cavity includes, but is not limited to, a right-angled profile, a bull-horn profile, or any other smoothly transitioned curved shape. This structure enables smooth material discharge.

[0017] 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. The contraction section has a gradually narrowing cross-section, the mixing section is a straight pipe section with a constant cross-section, and the divergence section has a gradually expanding cross-section. This variable-diameter structure further optimizes the gas-solid mixing effect, making the powder more stable during transport, reducing the risk of pipe blockage, and ensuring smooth long-distance transport.

[0018] Preferably, the metering chamber has a variable diameter structure, which includes an inlet expansion section connected to the outlet of the filling valve, an intermediate constant diameter metering section connected downstream of the inlet expansion section, and an outlet contraction section connected downstream of the intermediate constant diameter metering section and connected to the inlet of the injection valve. This variable diameter structure of the metering chamber facilitates the entry, accurate metering, and smooth ejection of powder, improving the metering accuracy and powder ejection efficiency, and ensuring the working performance of each metering unit.

[0019] This utility model, by employing a parallel, multi-channel, alternating continuous quantitative feeding system, aims to achieve the following beneficial effects compared to existing technologies:

[0020] (1) Achieving uninterrupted continuous supply, ensuring pile strength and uniformity: The most significant advantage of this invention lies in the fact that, through the alternating operation of two sets of quantitative feeding units (i.e., one set during injection and the other during filling), the inherent supply intermittent period of a single-path system is completely eliminated. This ensures that throughout the entire continuous drilling process, a stable flow of powder is always supplied to the system, fundamentally avoiding the occurrence of "material-free zones" in the pile body due to supply interruptions.

[0021] The risk of "material shortage zone" is greatly eliminated, ensuring the strength continuity and material distribution uniformity of the finished pile throughout the entire depth range.

[0022] (2) Significantly increases the upper limit of supply flow and broadens the adaptability of equipment to various working conditions: By adopting a multi-path parallel structure, the theoretical maximum supply flow of this utility model can reach twice that of a single-path system of the same type. This enables it to easily cope with construction conditions with large diameters and high admixture ratios that require large amounts of powder, solving the problem that existing single-path systems cannot handle such projects due to flow limitations, and greatly broadening the application range and engineering adaptability of the equipment.

[0023] (3) Optimized valve operating mode, effectively extending equipment service life: The multi-path parallel design of this utility model provides great flexibility in the valve operating mode. When pursuing high flow output, it is not necessary to drastically compress the single cycle time as in a single-path system. Instead, the task can be distributed to two branches, allowing the opening and closing frequency of individual valves to operate within a more reasonable and moderate range. This optimized operating mode effectively reduces the mechanical shock and fatigue accumulation of the valves, thereby significantly extending their overall service life and improving the durability and reliability of the equipment under long-term high-load operation.

[0024] (4) Possessing fault redundancy and fault tolerance capabilities, ensuring construction continuity and reducing overall costs: In a single-path system, if a valve fails during pile driving and cannot supply material, the operation must be stopped immediately for time-consuming troubleshooting and valve replacement. If a pile foundation that is halfway constructed is interrupted for a long time while waiting for backend fault repair, quality problems may occur, which may even lead to the scrapping of the pile site and waste. To avoid the above risks, the engineering often adopts the strategy of "periodic early replacement", that is, replacing the valve before it reaches its actual service life, resulting in waste of spare parts and labor costs. The parallel multi-path structure of this utility model provides valuable system fault tolerance capabilities. Once a valve in one branch fails, the control system can intelligently isolate it and rely on another intact branch to continue the material supply operation, achieving "working with defects". At this time, although the maximum supply flow of the system will be limited, the on-site operators can appropriately reduce the drilling speed of the front-end pile driver to match the current powder supply capacity, thereby ensuring that the construction process is not interrupted. This capability effectively avoids the serious consequences and waste of labor and materials that may be caused by the failure of a single component in a single-path system. 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, gas-solid mixing chamber, and gas delivery pipe structure of Embodiment 1 of this utility model;

[0031] Figure 7 This is a first-view overall structural diagram of the feeding unit according to Embodiment 1 of this utility model;

[0032] Figure 8 This is a schematic diagram of the overall structure of the feeding unit from a second perspective 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 construction method of Embodiment 1 of this utility model;

[0035] Figure 11 This is a schematic diagram of the quantitative feeding unit structure of Embodiment 1 of this utility model;

[0036] Figure 12 This is a schematic diagram illustrating the collaborative operation between Embodiment 1 of this utility model and the front-end.

[0037] Figure 13 This is a schematic diagram of the quantitative feeding unit structure in Embodiment 2 of this utility model;

[0038] Figure 14 This is a schematic diagram of the gas-solid mixing chamber in Embodiment 3 of this utility model;

[0039] Figure 15 This is a schematic diagram of the pneumatic conveying unit structure according to Embodiment 4 of this utility model;

[0040] Figure 16 This is a schematic diagram of the quantitative feeding unit, gas-solid mixing chamber, and gas delivery pipe structure of Embodiment 5 of this utility model;

[0041] Figure 17 This is a schematic diagram of the gas supply unit structure of Embodiment Six of this utility model. Detailed Implementation

[0042] 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.

[0043] Example 1

[0044] like Figures 1 to 12As shown, a multi-channel parallel airlock quantitative feeding powder spraying pile backing includes an air supply unit 1, a feeding unit 2, a quantitative feeding unit 6, a pneumatic conveying unit 3, a 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 refrigerated 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 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 feeding unit 2. The feeding unit 2 includes a conveying tank body 210, which is connected to the air supply unit 1 via a conveying tank inlet pipe 214 to deliver pressurized air. The discharge port of the conveying tank body 210 is connected to a guide pipe 216, specifically, as shown... Figure 10 and Figure 11As 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 conveying tank to the quantitative feeding unit 6. The longitudinal profile shape can also be a right-angle profile or any other smoothly transitioning curved shape. The discharge end of the guide pipe 216 is connected to at least two parallel-connected diversion pipes 301; in this embodiment, there are two diversion pipes 301, namely the first diversion pipe 301.a and the second diversion pipe 301.b. In specific applications, more parallel-connected diversion pipes 301 can also be used, such as three, four, etc., which is to add more on the basis of two. The structure is similar, and will not be described in detail here. Each branch pipe 301 is connected to a metering unit 6 (first metering unit 6.a and second metering unit 6.b) at its outlet. The discharge ends of the two metering units 6 converge with the air outlet of the pneumatic conveying unit 3 to form a gas-solid mixing chamber 305. The gas-solid mixing chamber 305 is provided with a pressure relief pipe vent 308 for further control of the internal pressure. Each metering unit 6 includes, in sequence along the material flow direction, a filling valve 61 (first filling valve 61.a and second filling valve 61.b), a metering chamber 62 with a predetermined volume (first metering chamber 62.a and second metering chamber 62.b), and an injection valve 63 (first injection valve 63.a and second injection valve 63.b). The inlet of the filling valve 61 is connected to the guide pipe 216; the outlet of the injection valve 63 is connected to the gas-solid mixing chamber 305 through the powder conveying pipe 307 (first powder conveying pipe 307.a and second powder conveying pipe 307.b); the control unit 4 is configured to coordinate the operation of the two quantitative feeding units 6 (first quantitative feeding unit 6.a and second quantitative feeding unit 6.b) to achieve an alternating cyclic working mode, thereby achieving continuous quantitative supply to the pneumatic conveying unit 3; the storage unit 5 is connected to the feeding unit 2 and is used to replenish the feeding unit 2. This back-end system enables continuous quantitative supply of powder, overcoming the intermittent supply caused by the sequential execution of "filling" and "spraying" in a single-path system. It avoids large periodic fluctuations in the distribution of the curing agent in the pile body, ensuring the overall uniformity and stable mechanical properties of the pile body. It significantly improves the system's peak flow rate and operational redundancy, enhances its applicability to large-diameter piles and high-dosage conditions, and inherits the core advantages of the single-path airlock quantitative feeding system, such as high precision and anti-clogging pipes. At the same time, it improves the system's operational reliability, reduces the impact of single-point failures on operations, increases the operational fault tolerance rate, and has superior overall performance, combining better reliability and economy.

[0045] Specifically, such as Figure 11 As shown, the control unit 4 is further configured to perform a basic quantitative feeding cycle for each quantitative feeding unit 6, including the following steps:

[0046] S1. Filling step: Control the injection valve 63 of the quantitative feeding unit 6 to be closed, and at the same time open its filling valve 61 so that the powder is filled into its quantitative chamber 62 from the guide pipe 216 under the preset pressure.

[0047] S2, Injection Step: After the filling step is completed, the filling valve 61 of the quantitative feeding unit 6 is closed, and then its injection valve 63 is opened according to the preset parameters to inject the powder stored in its quantitative chamber 62 into the gas-solid mixing chamber 305.

[0048] Specifically, such as Figure 6 As shown, the control unit 4 is further configured to coordinate the start, stop, and phase of the basic quantitative feeding cycles of the two quantitative feeding units 6, such that when any quantitative feeding unit 6 (e.g., the first quantitative feeding unit 6.a) executes the filling step a, at least one other quantitative feeding unit 6 (e.g., the second quantitative feeding unit 6.b) is executing the injection step b, thereby achieving a continuous and uninterrupted supply of powder to the gas-solid mixing chamber 305. By clearly defining the filling and injection steps of the basic quantitative feeding cycle of a single quantitative feeding unit 6 and specifying the coordination management method of the control unit for multiple sub-unit cycles, the stable operation of the alternating cycle working mode of "one set of injection, one set of preparation" is ensured. From the control logic perspective, it is guaranteed that when any quantitative feeding unit 6 executes the filling step, at least one other is executing the injection step, completely eliminating the supply intermittent period, realizing a continuous and uninterrupted supply of powder to the gas-solid mixing chamber, and further ensuring the uniformity of the pile body quality.

[0049] Specifically, such as Figure 5 , Figure 6 , Figure 10 and Figure 11As shown, the pneumatic conveying unit 3 includes a powder-gas injection assembly 30 and a powder-gas conveying pipe 31. The powder-gas injection assembly 30 includes a main air pipe 304 connected to the air supply unit 1 and at least one air delivery pipe 303. In this embodiment, two air delivery pipes 303 are used, namely the first air delivery pipe 303.a and the second air delivery pipe 303.b. In specific applications, more air delivery pipes 303 can also be used, such as three, four, etc., which is to add more on the basis of two. The structure is similar, and will not be described in detail here. The inlet ends of the first gas pipe 303.a and the second gas pipe 303.b converge and connect to the main gas pipe 304, which is equipped with a main gas circuit switch valve 418. The outlet ends of the first gas pipe 303.a and the second gas pipe 303.b converge and connect to the outlet ends of the two powder conveying pipes 307 (the first powder conveying pipe 307.a and the second powder conveying pipe 307.b) to a gas-solid mixing chamber 305. Each gas pipe 303 is equipped with a gas pipe switch valve 419 controlled by the control unit 4. The first gas pipe switch valve 419.a is on the first gas pipe 303.a, and the second gas pipe switch valve 419.b is on the second gas pipe 303.b. The air inlet of the air inlet pipe 214 on the conveying tank body 210 is connected to one of the air delivery pipes 303, and the outlet of the air inlet pipe 214 is connected to the top of the conveying tank body 210. A pressurization valve 413 is installed on the air inlet pipe 214. The inlet of the powder-gas conveying pipe 31 is connected to the gas-solid mixing chamber 305, and the outlet of the powder-gas conveying pipe 31 is connected to the piling machine 7. Through the structural design of the pneumatic conveying unit 3, the main air pipe 304, the air delivery pipes 303, and the corresponding switching valves provide a stable air source for powder conveying. The connection method of the air inlet pipe 214 efficiently provides a pressurized air source for the feeding unit, ensuring the smooth flow of powder within the feeding unit. Controlled by the air delivery pipe switching valve 419, the air delivery state can be flexibly adjusted. Combined with the operation of the quantitative feeding unit 6, this ensures the stability and reliability of the gas-solid mixing and conveying process, improving the overall coordination and controllability of the system.

[0050] Specifically, such as Figure 5 and Figure 6 As shown, two gas delivery pipes 303 are symmetrically distributed circumferentially along the gas-solid mixing chamber 305. The central axis of each gas delivery pipe 303 intersects the central axis of the gas-solid mixing chamber 305, with an included angle of less than 60°, preferably 30°. This design of the angle and distribution of the gas delivery pipes 303 and the gas-solid mixing chamber 305 facilitates thorough mixing of the airflow and powder, improving the gas-solid mixing efficiency and uniformity. Furthermore, the two gas delivery pipes 303 are symmetrically distributed circumferentially along the gas-solid mixing chamber 305.

[0051] Specifically, such as Figures 7 to 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 is 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 via 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; three are used in this embodiment, but more can also be used. The lower part of the load cell is fixed to the support frame 212, and its 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 provided with a feed valve 411 for replenishing powder curing agent. The conveying tank exhaust pipe 215 is located on the top of the conveying tank body 210, and the conveying tank exhaust pipe 215 is provided with a conveying tank exhaust valve 414. The top of the conveying tank body 210 is also provided with a conveying tank safety valve 415 to ensure the safety of air pressure inside the tank. A ladder is provided on one side of the support frame 212 for easy climbing and maintenance. The vibrator 213, the load cell 401, the feed valve 411, the conveying tank pressurization valve 413, the conveying tank exhaust valve 414, and the conveying tank safety valve 415 are all electrically connected to the central control cabinet 42 of the control unit 4. The structure of the feeding unit 2 (feed tank body 210, support frame 212, connecting flange 211, etc.) provides a stable basic structure for the storage and conveying of powder. The vibrator 213 at the bottom of the feeding tank body 210 can effectively solve the problems of powder arching or poor flow, ensuring that the powder can smoothly enter the guide pipe 216, and guaranteeing the filling efficiency and stability of the subsequent quantitative feeding unit 6.

[0052] Specifically, such as Figure 3 , 7 to Figure 9As shown, the control unit 4 includes a sensor group, a valve group, and a central control cabinet 42; the sensor group 40 includes three load cells 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 load cell 401 is fixed on the support frame 212, and the conveying tank body 210 is vertically pressed onto the load cells 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 on the main gas pipe 30 of the gas supply unit 1. 4. The valve group 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 main air pipe 304 of the air supply unit 1, the main air pipe 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.

[0053] The central control cabinet 42 is electrically connected to the valve assembly 41, the sensor assembly 40, and the filling valve 61 and injection valve 63 of the quantitative feeding unit 6. Through the electrical connection between the central control cabinet 42 and each component, centralized control and coordinated operation of the system are achieved, improving the system's automation level and operational reliability. The central control cabinet 42 is configured to periodically execute a quantitative feeding operation cycle including the following steps:

[0054] 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...

[0055] The tube 216 is filled into the metering chamber 62 with a defined volume until the predetermined injection conditions are met;

[0056] 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.

[0057] Specifically, such as Figure 10 and Figure 11 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.

[0058] 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.

[0059] Specifically, such as Figures 7 to 9 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.

[0060] Specifically, such as Figures 7 to 9 As shown, 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.

[0061] 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.

[0062] In this embodiment, combined with Figures 1 to 11 , Figure 13 The paper also discloses a construction method for a multi-channel parallel airlock quantitative feeding powder jet grouting pile back-end, including the following standard steps:

[0063] S1. Setting operating parameters: Set background operating parameters on the central control cabinet 42. The parameters include at least the following: working cycle parameters of each quantitative feeding unit 6 (first quantitative feeding unit 6.a and second quantitative feeding unit 6.b), including filling time, spraying time, etc.; the timing or phase relationship of alternating work between the two quantitative feeding units 6; the preset working pressure of the conveying tank body 210; the weight of the conveying tank 210 to be loaded; and the residual threshold of the powder curing agent for starting automatic replenishment.

[0064] 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, fill the conveying tank body 210 with powder curing agent to the preset weight, and then close the relevant valves;

[0065] S3. System Start-up and Pre-pressurization: Start the air supply unit 1 and pressurize the conveying tank body 210 to the preset working pressure. At the same time, start the pneumatic conveying unit 3 to establish a stable conveying airflow in the conveying pipeline. The background enters the standby state.

[0066] S4. Execute parallel alternating continuous quantitative feeding: After receiving the start spraying operation command from the front-end piling machine 7, the control unit 4 immediately drives and coordinates at least two quantitative feeding units 6 (first quantitative feeding unit 6.a and second quantitative feeding unit 6.b) to enter an alternating cyclic working mode according to preset parameters and timing relationships, so as to achieve uninterrupted powder supply to the pneumatic conveying unit 3. The characteristic of this working mode is:

[0067] (a) When the first quantitative feeding unit 6.a performs its filling step, the second quantitative feeding unit 6.b simultaneously performs its spraying step;

[0068] (b) When the first quantitative feeding unit 6.a completes the filling and enters the spraying step, the second quantitative feeding unit 6.b simultaneously completes the spraying and enters the filling step. The two sub-units switch seamlessly in this way.

[0069] S5. On-demand replenishment of conveying tank: During operation, when the remaining powder in the conveying tank body 210 is detected to be lower than the preset threshold, the feeding cycle is automatically paused and linked with the front-end piling machine 7 to execute the automatic replenishment program to the conveying tank body 210. After completion, the operation is resumed.

[0070] S6. Single pile operation completed: After receiving the operation completion instruction from the front-end pile driver 7, stop the material feeding cycle, close all valves, and complete this operation; while waiting for the new pile operation instruction, repeat the operation process of steps S1 to S5.

[0071] Example 2

[0072] 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.

[0073] 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.

[0074] Example 3

[0075] Embodiment 3 is another implementation of this utility model, such as... Figure 14 As 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.

[0076] 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.

[0077] 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.

[0078] Example 4

[0079] This embodiment is generally similar in structure to the previous embodiment, the key difference being that, as Figure 15 As shown, in this embodiment, there is one air supply pipe 419. It is a more simplified and economical airlock quantitative feeding solution that can also achieve reliable powder filling and discharge, meeting the basic requirements of quantitative feeding.

[0080] The detailed usage method of the construction backend described 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.

[0081] Example 5

[0082] This embodiment is another preferred implementation of the present invention, aiming to provide a more stable and seamless continuous supply. Its hardware structure is basically similar to the aforementioned dual-path parallel embodiment, with the main difference being that... Figure 16As shown, its quantitative feeding unit 6 structurally includes three quantitative feeding units 6 arranged in parallel (first quantitative feeding unit 6.a, second quantitative feeding unit 6.b, and third quantitative feeding unit 6.c). To achieve continuous supply, the control unit 4 is configured to execute a "relay-style" cyclical working strategy for these three quantitative feeding units 6. The characteristic of this strategy is that at any given time, the system always maintains a state of "one unit spraying, one unit filling, and one unit on standby," ensuring that there is always material being sprayed from the main discharge port.

[0083] Its typical loop process is as follows:

[0084] S1: Initial stage: The first quantitative feeding unit 6.a performs spraying, while the second quantitative feeding unit 6.b performs filling, and the third quantitative feeding unit 6.c has completed filling and is in a full-material standby state.

[0085] S2: First switch: After the first quantitative feeding unit 6.a completes the spraying, the third quantitative feeding unit 6.c, which is in a full-material standby state, immediately takes over seamlessly and begins to perform spraying; at the same time, the first quantitative feeding unit 6.a enters the filling step, while the second quantitative feeding unit 6.b completes the filling and enters the full-material standby state.

[0086] S3: Second switch: After the third quantitative feeding unit 6.c completes the spraying, the second quantitative feeding unit 6.b, which is in a full-material standby state, immediately takes over the spraying; at the same time, the third quantitative feeding unit 6.c enters the filling step, and the first quantitative feeding unit 6.a completes the filling and enters the full-material standby state.

[0087] S4: Third switch: After the second quantitative feeding unit 6.b completes the spraying, the first quantitative feeding unit 6.a, which is in a full-material standby state, takes over the spraying again, and the system returns to the initial stage, and so on.

[0088] Through the three-stage cycle described above, a continuous and uninterrupted material supply is achieved from the main discharge port. Compared to the dual-path alternating scheme, this three-path "relay" scheme has unique advantages: because one unit is always in a "full and ready" state, the "handover" process of the injection task can achieve a seamless switch with zero delay, resulting in a more stable and uniform final output material flow. In addition, this mode also allows more time for the filling step of each unit, which is particularly advantageous for materials with poor flowability or those that require a longer time to reliably fill.

[0089] Example 6

[0090] This embodiment is generally similar in structure to the previous embodiment, the key difference being that, as Figure 17As shown, the air supply unit 1 in this embodiment is equipped with two sets of air supply modules. Each set of air supply modules consists of an air compressor 11, an air storage tank 12, and a refrigerated dryer 13 connected in series.

[0091] In this configuration, the first air supply module is dedicated to supplying the high-pressure gas required for conveying the powder-gas injection assembly 30; while the second air supply module independently provides pressurized gas to the conveying tank body 210. This design, which separates the pressurized gas source for the conveying tank from the main powder conveying gas source, effectively avoids pressure fluctuations and gas usage interference between the two.

[0092] The main advantages of this embodiment are: the pressure of the conveying tank is more stable and controllable, the independent air source ensures that the pressure inside the conveying tank body 210 is accurate and has small fluctuations, and can be maintained at a higher level as needed, thereby more reliably supporting the construction of dry spray mixing piles with larger pile lengths and ensuring the quality of deep piles.

[0093] The detailed usage method of the construction backend described 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.

[0094] In summary, this utility model, by employing a parallel multi-path, alternating continuous quantitative feeding system, aims to achieve the following beneficial effects compared to existing technologies: uninterrupted continuous supply, ensuring pile strength and uniformity; significantly increasing the upper limit of supply flow rate, broadening the equipment's adaptability to various operating conditions; optimizing valve operating modes, effectively extending equipment lifespan; and possessing fault redundancy and fault tolerance capabilities, ensuring construction continuity and reducing overall costs. The parallel multi-path structure of this utility model provides valuable system fault tolerance. If a valve in one branch fails, the control system can intelligently isolate it and continue supplying material using another intact branch, achieving "operation with a fault." While the system's maximum supply flow rate may be limited, on-site operators can appropriately reduce the drilling speed of the front-end piling machine to match the current powder supply capacity, thus ensuring uninterrupted construction. This capability effectively avoids the serious consequences and waste of labor and materials that could result from a single component failure in a single-path system.

[0095] 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 multi-channel parallel airlock quantitative feeding powder jet grouting support system, characterized in that, The system includes an air supply unit (1), a material supply unit (2), 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 outlet of the material supply unit (2) is connected to at least two diversion pipes (301). The outlet of each diversion pipe (301) is connected to a quantitative feeding unit (6). The outlets of all quantitative feeding units (6) are connected to the outlet of the pneumatic conveying unit (3). The end is connected to a gas-solid mixing chamber (305); each metering unit (6) includes a filling valve (61), a metering chamber (62) and an injection valve (63) in sequence along the material flow direction; the inlet of the filling valve (61) is connected to the outlet of the feeding unit (2); the outlet of the injection valve (63) is connected to the inlet of the gas-solid mixing chamber (305); the control unit (4) is configured to coordinate the operation of at least two metering units (6) to achieve an alternating cyclic working mode, thereby achieving continuous metering of powder to the pneumatic conveying unit (3).

2. The multi-channel parallel airlock quantitative feeding powder jet grouting backing system according to claim 1, characterized in that, The pneumatic conveying unit (3) includes a powder-gas injection assembly (30), which includes a main air pipe (304) connected to the air supply unit (1) and at least one air delivery pipe (303). The air inlet of the air delivery pipe (303) is connected to the main air pipe (304), and a main air circuit switch valve (418) is provided on the main air pipe (304). The air outlet of the air delivery pipe (303) is connected to the outlet of all the metering feeding units (6) and is connected to a gas-solid mixing chamber (305). Each air delivery pipe (303) is provided with an air delivery pipe switch valve (419) controlled by the control unit (4).

3. The multi-channel parallel airlock quantitative feeding powder jet grouting backing system according to claim 2, characterized in that, The central axis of each gas pipe (303) intersects the central axis of the gas-solid mixing chamber (305), and the included angle is less than 60°.

4. The multi-channel parallel airlock quantitative feeding powder jet grouting backing system according to claim 2, characterized in that, When there are multiple gas pipelines (303), all gas pipelines (303) are symmetrically distributed circumferentially along the gas-solid mixing chamber (305), or spaced apart axially along the gas-solid mixing chamber (305).

5. The multi-channel parallel airlock quantitative feeding powder jet grouting backing system according to claim 2, characterized in that, The feeding unit (2) is connected to the air supply unit (1) through the air inlet pipe (214) of the feeding tank and realizes the pressurized air source delivery. The air inlet end of the air inlet pipe (214) of the feeding tank is connected to one of the air supply pipes (303), and the air outlet end of the air inlet pipe (214) of the feeding tank is connected to the feeding unit (2).

6. The multi-channel parallel airlock quantitative feeding powder jet grouting backing system according to claim 5, characterized in that, The feeding unit (2) includes a conveying tank body (210), a support frame (212), a connecting flange (211), a guide pipe (216), and a conveying tank exhaust pipe (215); 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 feed ends of all the branch pipes (301) are connected to the discharge end of the guide pipe (216); at least one 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 multi-channel parallel airlock quantitative feeding powder jet grouting backing system according to 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 (410). 210); the valve group includes a feed valve (411), a conveying tank pressurization valve (413) and a conveying tank exhaust valve (414); the feed valve (411) is installed on the conveying tank body (210) and is used for replenishing the powder curing agent; the conveying tank pressurization valve (413) is installed on the conveying tank air inlet pipe (214); the conveying tank exhaust valve (414) is installed on the conveying tank exhaust pipe (215); the central control cabinet (42) is installed on the support frame (212); the central control cabinet (42) is electrically connected to the vibrator (213), the valve group, the sensor group and the quantitative feeding unit (6).

8. The multi-channel parallel airlock quantitative feeding powder jet grouting backing system according to claim 6, characterized in that, The longitudinal profile shape of the guide tube (216) in the vertical plane containing the central axis of the metering cavity (62) includes, but is not limited to, a right-angled profile, a bull-horn profile, or a curved shape with any smooth transition.

9. The multi-channel parallel airlock quantitative feeding powder jet grouting backing system 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 multi-channel parallel airlock quantitative feeding powder jet grouting backing system according to claim 1, characterized in that, The metering chamber (62) is a variable diameter structure, which 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).

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