A high-pressure jetting backflushing pipe pressure-limiting isolation cleaning system and a use method thereof

Abstract

The application discloses a high-pressure rotary jet backflushing pipe pressure-limiting isolation cleaning system and a use method, and belongs to the technical field of high-pressure rotary jet construction auxiliary equipment. The system is provided with an isolation detection cavity between a hole side isolation valve and a cleaning side isolation valve, and a pressure detection assembly is connected to the detection cavity and a backflushing pipe section to be cleaned respectively; a cleaning pump is connected to the pipe section to be cleaned through a pressure limiting valve and a one-way valve, the pipe section is connected to a buffer tank through a pressure relief valve, and a remote end is connected to a blowdown assembly. The method comprises the steps of stopping and isolating, checking and isolating, pressure-limiting cleaning, stopping and pressure releasing, and recovering backflushing. The application reduces the risk of cleaning pressure transmission to the hole side and residual pressure retention after stopping through isolation checking, cleaning pressure limiting and independent pressure releasing cooperation, and is suitable for the cleaning of ground backflushing elbow pipes, horizontal pipes and variable-diameter pipe sections.

Description

Technical Field

[0001] This invention belongs to the technical field of high-pressure jet grouting construction auxiliary equipment, specifically relating to a high-pressure jet grouting return pipe pressure limiting isolation cleaning system and its usage method. Background Technology

[0002] High-pressure jet grouting utilizes jet grout to cut and mix the surrounding soil. Part of the grout mixes with soil particles, groundwater, and air bubbles before returning through the orifice and being transported to collection or treatment facilities via surface return pipes. When the return grout velocity decreases, during construction pauses, or when the pipeline makes local bends, particles are prone to deposition. As the cement grout continues to solidify, an adhesion layer may form at bends, reducers, and low points, gradually reducing the flow cross-section.

[0003] Clean water flushing relies on water flow to remove loose sediment, and its effectiveness depends on the flow area, the degree of sediment adhesion, and the unobstructedness of the outlet. When a pipe section is completely blocked, increasing the water supply may not necessarily create flushing flow, but may instead cause the pressure in front of the blockage to rise first; sudden movement of the blockage may also cause pressure fluctuations. Therefore, the cleaning pressure cannot be directly copied from the jet grouting pressure, nor can the fact that the pump has stopped be taken as evidence that there is no residual pressure in the pipe.

[0004] On the return pipe connected to the slurry jet orifice, if only one valve is closed before water is supplied for cleaning, water pressure may be transmitted to the orifice side due to sand inclusion in the valve seat, wear, or the valve not being closed tightly. Even if two valves are installed, simply observing the stability of the pressure in the middle chamber may be affected by factors such as blocked pressure interfaces, similar pressure on both sides, or insufficient observation time; pressure stability can only be used as a basis for judgment under specified inspection conditions and cannot prove the absolute absence of leakage on its own.

[0005] Chinese patent application CN113477638A discloses a "pipeline scale cleaning skid" that uses a water pump unit and an in-pipe cleaning ball device for scale removal, and sets up pressure protection and monitoring components after the pump. This solution focuses on the coordination of cleaning tools and water supply equipment. However, its disclosed solution does not include a pre-cleaning inspection arrangement for the swirl jet orifice side with a double isolation valve and an intermediate detection chamber, and therefore cannot directly replace the orifice-side isolation inspection required in this application.

[0006] Chinese patent application CN102052997A discloses a "method and system for detecting fluid valve leakage," which involves filling a control volume with fluid and then using the pressure change rate of another control volume to determine valve leakage. While this solution provides a framework for pressure change detection, its disclosed content does not cover the isolation and cleaning process for rotary jet return pipes. Further specific configuration is needed, incorporating pressure interface checks under conditions of particulate-containing return slurry, remote drainage, and shutdown pressure relief.

[0007] In order to solve the above problems, this invention proposes a high-pressure rotary jet slurry return pipe pressure limiting isolation cleaning system and its usage method. Summary of the Invention

[0008] To address the aforementioned technical problems in existing technologies, this invention proposes a high-pressure rotary jet slurry return pipe pressure-limiting isolation cleaning system and its usage method, overcoming the shortcomings of existing technologies. By setting a detection chamber between the two isolation valves and combining it with liquid discharge, pressure observation, and low-pressure water flow checks, misjudgments of the isolation status are reduced, solving the problem that leaks are difficult to detect by simply looking at the valve position; the cleaning pressure is controlled by pressure-limiting water supply and overpressure pump shutdown, eliminating the risk of continuous pressurization; and residual pressure is released through an independent pressure relief pipe and a venting buffer tank, solving the problem of pressure retention and mutual interference between discharge after shutdown.

[0009] To achieve the above objectives, the present invention adopts the following technical solution: A high-pressure rotary jet cleaning system for pressure-limiting and isolating return pipes includes an isolation component, a pressure detection component, a pressure-limiting cleaning component, a pressure relief buffer component, and a drain component. The isolation component includes an orifice-side isolation valve, an isolation detection chamber, and a cleaning-side isolation valve connected sequentially along the return pipe direction. The outlet of the cleaning-side isolation valve is connected to the inlet of the return pipe section to be cleaned. The drain component includes a drain valve, a drain pipe, and a collection container. The drain valve is connected to the collection container via the drain pipe and connected to the distal end of the return pipe section to be cleaned. The pressure detection component is connected to the isolation... The detection chamber is connected to the slurry return pipe section to be cleaned; the pressure limiting cleaning assembly includes a cleaning pump, a pressure limiting valve, and a check valve. The outlet of the cleaning pump is connected to the slurry return pipe section downstream of the cleaning-side isolation valve via a liquid supply shut-off valve, a pressure limiting valve, and a check valve in sequence. The conduction direction of the check valve is towards the slurry return pipe section to be cleaned; the pressure relief buffer assembly includes a pressure relief valve and a buffer tank. The inlet of the pressure relief valve is connected to the slurry return pipe section to be cleaned, and the outlet is connected to the buffer tank via a pressure relief pipe. The isolation detection chamber is also connected to the buffer tank via an independent discharge pipe with a discharge valve.

[0010] Preferably, the isolation detection chamber is a short pipe cavity connected at both ends to the orifice-side isolation valve and the cleaning-side isolation valve via flanges. The cavity is provided with a pressure port and a discharge port. The pressure detection assembly includes a pressure gauge or pressure sensor installed on the pressure port, and a pressure switch connected to the slurry return pipe section to be cleaned. The normally closed contact of the pressure switch is connected in series with the contactor control circuit of the cleaning pump.

[0011] Preferably, the pressure limiting valve is a pressure reducing valve with a pressure regulating element, and the cleaning pump is a water pump with flow-stopping and pressure-limiting characteristics or a return-flow pressure limiting valve is installed at its outlet.

[0012] Preferably, the pressure relief valve is a spring-loaded pressure relief valve with a manual opening mechanism, and the buffer tank is provided with a vent and a drain port; the pressure relief pipe and the independent drain pipe are respectively connected from the top of the buffer tank, and an air gap is left between the outlet of each pipe and the highest allowable liquid level of the buffer tank, and the two pipes are not connected to each other before being connected to the buffer tank.

[0013] A method for using a high-pressure rotary jet slurry return pipe pressure limiting and isolation cleaning system includes the following steps: Step 1, shutdown and isolation: Stop the rotary jet injection and slurry return suction. After confirming the discharge conditions on the hole side, close the hole side isolation valve and the cleaning side isolation valve, and connect the far end of the slurry return pipe section to be cleaned to the sewage discharge assembly. Step 2, Check Isolation: Open the drain valve of the isolation detection chamber, check the actual drain and pressure drop, and after closing the drain valve, read the chamber pressure change within the predetermined observation time; under the condition that the orifice side pressure is known and there is a distinguishable pressure difference between it and the chamber pressure, and the chamber pressure change does not exceed the preset range, supply water to the slurry return pipe section to be cleaned at low pressure for a short time, and check the chamber pressure and the distant drain at the same time; stop the water supply if any abnormality occurs or if the inspection conditions are not met. Step 3, pressure limiting cleaning: After the inspection is passed, adjust the pressure limiting valve to the predetermined cleaning pressure, start the cleaning pump, and supply water to the slurry return pipe section to be cleaned through the check valve. Keep the sewage discharge component connected and observe the chamber pressure, cleaning pressure and drainage status. Step 4, Shutdown and Pressure Relief: When cleaning is completed or abnormal chamber pressure, excessive cleaning pressure, or obstructed drainage occurs, stop the cleaning pump and close the liquid supply shut-off valve. Discharge the residual medium to the buffer tank through the pressure relief valve and keep both isolation valves closed. Step 5, restore slurry return: Confirm that the residual pressure in the cleaning pipeline has been released and the abnormality has been eliminated, exit the cleaning liquid supply branch, close the drain valve, switch the drain end back to the normal slurry return direction, slowly open the cleaning side isolation valve, and then slowly open the orifice side isolation valve to check the connection and slurry return status.

[0014] Preferably, in step two, the pressure reading is compared with the actual liquid discharge before and after the liquid discharge; if no actual liquid discharge is observed, the pressure reading does not change with the liquid discharge, or the cavity pressure continues to rise after the liquid discharge valve is closed, the inspection and cleaning of the pressure interface or the repair of the isolation valve is stopped; when the cavity pressure rises with the cleaning side pressure during low-pressure water supply, or when there is no liquid discharge at the remote end, the water supply is stopped.

[0015] Preferably, in step three, the set pressure of the pressure limiting valve is lower than the stop pressure of the pressure switch, and the opening pressure of the pressure relief valve is higher than the stop pressure of the pressure switch; each set value, together with the corresponding action deviation and pressure surge, does not exceed the allowable working pressure of the connected pipe fitting.

[0016] Preferably, in step four, when the cleaning pressure reaches the shutdown pressure of the pressure switch, the pressure switch disconnects the contactor control circuit of the cleaning pump; after the liquid supply stops, the pressure relief valve is manually opened to release the residual pressure below its automatic opening pressure, and the pressure at the inlet of the slurry return pipe section to be cleaned and the pipe section that may be separated by blockages are checked before resuming operation.

[0017] The beneficial technical effects of this invention are as follows: By forming a series structure with an orifice-side isolation valve, an isolation detection chamber, and a cleaning-side isolation valve, an independent pressure observation position can be obtained between the two valves. By combining the reading changes during liquid discharge and the chamber pressure changes during low-pressure water flow, some valve leaks, pressure interface blockages, and abnormal discharges can be detected, reducing the need to make judgments based solely on the valve handle position or a single static reading.

[0018] The water supply branch consists of a cleaning pump, a pressure limiting valve, and a check valve, allowing cleaning water to enter the pipe section to be cleaned from outside the isolation range on the orifice side. The pressure switch cuts off the pump control circuit when the pressure exceeds the limit, and the mechanical pressure relief valve serves as another pressure release path, reducing the risk of pressure rise caused by continuous water supply and abnormal valve operation.

[0019] The residual medium after shutdown is directed to the collection position through a pressure relief valve with a manual opening mechanism and a venting buffer tank; the discharge pipe of the detection chamber and the pressure relief pipe of the cleaning chamber are not connected to each other before entering the buffer tank, and an air gap is maintained to reduce the possibility of back pressure transmission from the cleaning chamber to the detection chamber through the shared closed pipeline.

[0020] The flushing outlet is maintained by a remote sewage discharge assembly, and the ground return slurry pipeline is connected using a flanged short pipe structure, facilitating the cleaning of bends, horizontal pipes, and diameter changes. On-site operations only require five steps: isolation, inspection, cleaning, depressurization, and restoration. Basic protection does not rely on multi-level metering or complex calculation programs. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the overall structure and connection of a high-pressure rotary jet slurry return pipe pressure limiting isolation cleaning system and its usage method according to the present invention.

[0022] Figure 2 This is a schematic diagram illustrating the operation process of a high-pressure rotary jet slurry return pipe pressure limiting isolation cleaning system and its usage method according to the present invention.

[0023] Among them: 1-hole side isolation valve, 2-isolation detection chamber, 3-cleaning side isolation valve, 4-pressure detection component, 5-pressure limiting cleaning component, 6-pressure relief buffer component, 7-drainage component. Detailed Implementation

[0024] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments: Example

[0025] like Figure 1-2As shown, a high-pressure rotary jet slurry return pipe pressure limiting and isolation cleaning system includes an isolation component, a pressure detection component 4, a pressure limiting cleaning component 5, a pressure relief buffer component 6, and a sewage discharge component 7. The isolation component includes an orifice-side isolation valve 1, an isolation detection chamber 2, and a cleaning-side isolation valve 3 connected sequentially along the slurry return direction. The outlet of the cleaning-side isolation valve 3 is connected to the inlet of the slurry return pipe section to be cleaned. The sewage discharge component 7 includes a sewage discharge valve, a sewage discharge pipe, and a collection container. The sewage discharge valve is connected to the collection container via the sewage discharge pipe and connected to the distal end of the slurry return pipe section to be cleaned. The pressure detection component 4... The isolation detection chamber 2 and the slurry return pipe section to be cleaned are respectively connected; the pressure limiting cleaning assembly 5 includes a cleaning pump, a pressure limiting valve and a check valve. The outlet of the cleaning pump is connected to the slurry return pipe section downstream of the cleaning side isolation valve 3 via the liquid supply shut-off valve, the pressure limiting valve and the check valve in sequence. The conduction direction of the check valve is towards the slurry return pipe section to be cleaned; the pressure relief buffer assembly 6 includes a pressure relief valve and a buffer tank. The inlet of the pressure relief valve is connected to the slurry return pipe section to be cleaned, and the outlet is connected to the buffer tank via the pressure relief pipe. The isolation detection chamber 2 is also connected to the buffer tank via an independent discharge pipe with a discharge valve.

[0026] Preferably, the isolation detection chamber 2 is a short pipe cavity connected at both ends to the orifice-side isolation valve 1 and the cleaning-side isolation valve 3 via flanges. The cavity is provided with a pressure port and a discharge port. The pressure detection assembly 4 includes a pressure gauge or pressure sensor installed on the pressure port, and a pressure switch connected to the slurry return pipe section to be cleaned. The normally closed contact of the pressure switch is connected in series with the contactor control circuit of the cleaning pump.

[0027] Preferably, the pressure limiting valve is a pressure reducing valve with a pressure regulating element, and the cleaning pump is a water pump with flow-stopping and pressure-limiting characteristics or a return-flow pressure limiting valve is installed at its outlet.

[0028] Preferably, the pressure relief valve is a spring-loaded pressure relief valve with a manual opening mechanism, and the buffer tank is provided with a vent and a drain port; the pressure relief pipe and the independent drain pipe are respectively connected from the top of the buffer tank, and an air gap is left between the outlet of each pipe and the highest allowable liquid level of the buffer tank, and the two pipes are not connected to each other before being connected to the buffer tank.

[0029] A method for using a high-pressure rotary jet slurry return pipe pressure limiting and isolation cleaning system includes the following steps: Step 1, shutdown and isolation: Stop the rotary jet injection and slurry return suction. After confirming the discharge conditions on the hole side, close the hole side isolation valve 1 and the cleaning side isolation valve 3, and connect the far end of the slurry return pipe section to be cleaned to the sewage discharge assembly 7. Step 2, Check Isolation: Open the drain valve of isolation detection chamber 2, check the actual drain and pressure drop, and read the chamber pressure change within the predetermined observation time after closing the drain valve; under the condition that the orifice side pressure is known and there is a distinguishable pressure difference between it and the chamber pressure, and the chamber pressure change does not exceed the preset range, supply water to the slurry return pipe section to be cleaned at low pressure for a short time, and check the chamber pressure and the distant drain at the same time; stop the water supply if any abnormality occurs or if the inspection conditions are not met. Step 3, pressure limiting cleaning: After the inspection is passed, adjust the pressure limiting valve to the predetermined cleaning pressure, start the cleaning pump, and supply water to the slurry return pipe section to be cleaned through the check valve. Keep the sewage discharge component 7 connected and observe the chamber pressure, cleaning pressure and drainage status. Step 4, Shutdown and Pressure Relief: When cleaning is completed or abnormal chamber pressure, excessive cleaning pressure, or obstructed drainage occurs, stop the cleaning pump and close the liquid supply shut-off valve. Discharge the residual medium to the buffer tank through the pressure relief valve and keep both isolation valves closed. Step 5, restore slurry return: Confirm that the residual pressure in the cleaning pipeline has been released and the abnormality has been eliminated, exit the cleaning liquid supply branch, close the drain valve, switch the drain end back to the normal slurry return direction, slowly open the cleaning side isolation valve 3, and then slowly open the hole side isolation valve 1, and check the connection and slurry return status.

[0030] Preferably, the pressure reading is compared with the actual discharge situation before and after the discharge; if no actual discharge is observed, the pressure reading does not change with the discharge, or the cavity pressure continues to rise after the discharge valve is closed, the inspection and cleaning of the pressure interface or the repair of the isolation valve should be stopped; if the cavity pressure rises with the cleaning side pressure during low-pressure water supply, or if there is no discharge at the remote end, the water supply should be stopped.

[0031] Preferably, in step three, the set pressure of the pressure limiting valve is lower than the stop pressure of the pressure switch, and the opening pressure of the pressure relief valve is higher than the stop pressure of the pressure switch; each set value, together with the corresponding action deviation and pressure surge, does not exceed the allowable working pressure of the connected pipe fitting.

[0032] Preferably, in step four, when the cleaning pressure reaches the shutdown pressure of the pressure switch, the pressure switch disconnects the contactor control circuit of the cleaning pump; after the liquid supply stops, the pressure relief valve is manually opened to release the residual pressure below its automatic opening pressure, and the pressure at the inlet of the slurry return pipe section to be cleaned and the pipe section that may be separated by blockages are checked before resuming operation. Example

[0033] like Figure 1-2 As shown, this embodiment further explains the system connection and operation basis. The equipment is installed on the ground return grout pipe and does not share the cleaning liquid supply port with the jet grouting high-pressure injection pipe.

[0034] The orifice-side isolation valve 1 is located after the orifice return slurry interface, and the cleaning-side isolation valve 3 is located before the cleaning water supply inlet. The isolation detection chamber 2 is sandwiched between the two valves. Both isolation valves can be full-bore valves suitable for slurry-containing liquids, with their pressure resistance, sealing direction, and particle throughput capacity selected according to the site piping. When both valves are closed, cleaning water can only enter the pipe section to be cleaned from downstream of the cleaning-side isolation valve 3. The flanged short pipe facilitates the disassembly and inspection of the valve seats and the cleaning of sediment within the chamber.

[0035] The pressure detection component 4 uses a pressure gauge that is easy to observe directly at the isolation detection chamber 2, or a pressure sensor with equivalent reading function. The pressure interface should be as short as possible and easy to disassemble and clean. A pressure gauge and pressure switch are installed at the inlet of the cleaning pipe section; the two readings represent the status of the intermediate chamber and the cleaning pipe section, respectively, and the reading at the outlet of the cleaning pump cannot be used to replace the actual pressure at all locations. Figure 1 The pressure detection component 4 is marked with a pressure gauge in the detection chamber, and the instrument on the cleaning side belongs to another measuring point of the same component.

[0036] The pressure-limiting cleaning assembly 5 consists of a cleaning pump, a pressure limiting valve, and a check valve. Figure 1 The component markings point to the pump set. The cleaning pump draws water from a clean water source, and its outlet connects to the downstream of the cleaning-side isolation valve 3 via a supply shut-off valve, a pressure limiting valve, and a check valve. The pressure limiting valve is an adjustable pressure reducing valve; the cleaning pump should have pressure limiting characteristics suitable for stop-flow conditions. When using a positive displacement pump, a backflow pressure limiting valve should also be installed at the pump outlet to prevent the pump side from continuing to pressurize when the downstream is closed, even with only a pressure reducing valve.

[0037] The pressure relief buffer assembly 6 consists of a pressure relief valve and a buffer tank. Figure 1 The component markings point to the buffer tank. The pressure relief valve extends independently from near the inlet of the section of pipe to be cleaned, with its outlet leading to the buffer tank. The spring actuates under the opening force generated by the inlet pressure; the valve opens when the set pressure is reached and reseats after the pressure drops. This automatic reseat does not mean the pipe is depressurized; therefore, the pressure relief valve has a manual opening mechanism, which the operator keeps open after the pump stops to release residual pressure below the automatic opening pressure. The pressure relief branch must not be interrupted by another closed shut-off valve during cleaning.

[0038] The buffer tank employs a collection structure open to the atmosphere. Liquid enters, slows down, and is collected; it is not described as a sealed storage tank capable of absorbing unlimited energy. The pressure relief pipe and the discharge pipe for the detection chamber enter from the top of the tank, with each outlet above the maximum permissible liquid level. Anti-splash measures should be in place during discharge and pressure relief, and the vents must not be blocked. Receiving space should be reserved according to the maximum possible discharge volume and shutdown delay. Cleaning should cease and the tank emptied before the liquid level reaches the upper limit of the permissible range; the tank cannot continue to bear pressure through a sealed body.

[0039] The drain assembly 7 is located at the far end, not next to the cleaning water supply interface, and includes a drain valve, drain pipe, and collection container. Water discharge at the near end only indicates that the nearby branch is unobstructed; actual discharge at the far end is necessary to confirm the existence of a passageway in the pipe section to be cleaned. Before installation, it should be confirmed that the existing orifice-side drainage conditions on site meet the shutdown and isolation requirements; if not, the orifice-side channel should not be closed for cleaning, and active suction should not be used to forcibly reduce the orifice-side pressure. This system does not have a separate orifice-side drainage mechanism.

[0040] Before conducting an isolation check, first confirm that the pressure port and drain port can transmit pressure changes normally. Then observe the chamber pressure after closing the drain valve. The chamber pressure may increase over time due to fluid entering through the valve seat from the orifice side, or it may be affected by residual pressure on the cleaning side or temperature changes. Therefore, not all chamber pressure changes should be directly attributed to a single valve. During the check, the orifice pressure status must be recorded. Pressure observation is only meaningful for leaks in the corresponding direction if a identifiable pressure differential exists. Cleaning permission should not be issued if the orifice pressure is unclear, the pressure differential is insufficient, or the reading is questionable. Repair or physical disconnection and isolation should be performed for further processing.

[0041] Low-pressure water flushing is a brief check of the cleaning-side connections and remote discharge, not a forced pressurization of completely blocked pipe sections. The test water pressure and duration should be within the allowable range on site, and should be stopped immediately if the cavity pressure rises or no water is discharged remotely. This check does not prove that there are no leaks in the valves at all pressures, and the cavity pressure should be continuously monitored during the formal cleaning process; continuous water flushing is not applicable to severely consolidated or completely blocked pipes, and the pressure should be released to confirm before disassembling the pipe.

[0042] Pressure limiting settings only require specifying the sequence of three actions: normal cleaning, overpressure shutdown, and mechanical pressure relief; complex models are not necessary. The normal cleaning pressure should be lower than the pressure switch shutdown value, and the shutdown value should be lower than the pressure relief valve opening value, allowing for instrument error and operational deviation between each value. Pressure surge during the shutdown process should also be considered to ensure that the highest possible pressure does not exceed the lowest permissible working pressure among hoses, flanges, valves, and pipe sections. Orifice-side pressure variation limits are determined separately based on the geological formation and construction conditions; the pressure resistance value of pipe fittings cannot replace the permissible orifice-side pressure.

[0043] For water flow to effectively remove sediment, a pathway must exist between the inlet and outlet. With the same water supply, a smaller cross-section due to sediment will increase flow resistance, manifesting as increased inlet pressure or reduced outlet discharge. Simply increasing the water supply pressure does not equate to improved cleaning effectiveness. On-site observations are based on a gradual decrease in discharge from the distal outlet, continuous drainage, and a cessation of abnormal inlet pressure increases; these phenomena are not equated with the quantitative descaling rate verified in existing experiments.

[0044] Automatic pump shutdown can be achieved via a pressure switch and a standard contactor, eliminating the need for a complex controller. When the pressure switch exceeds its limit, the contactor control circuit is disconnected. After resetting, the pump is manually restarted to prevent repeated automatic restarts due to pressure drops. In case of abnormal chamber pressure, interrupted drainage, or the buffer tank nearing full, on-site personnel should press the emergency stop button and close the supply shut-off valve. The pump stops upon power failure, and both isolation valves remain closed; the mechanical pressure relief function is independent of the control power supply.

[0045] After shutdown, check the pressure at all points blocked by obstructions or one-way valves. A zero inlet gauge does not prove there is no residual pressure on the other side of the blockage. For unconfirmed blocked areas, check using the existing safety pressure test and drain ports; do not loosen the flange to test for pressure release. When resuming operation, first confirm that the water supply branch has been disconnected and the drain has been switched back to its normal direction before slowly opening the isolation valve to avoid directly releasing residual cleaning pressure to the orifice side. Example

[0046] like Figure 1-2 As shown, a section of a horizontal ground-level slurry return pipe with an elbow is used as an example. This pipe section experienced a decrease in slurry discharge, but still maintained flow capacity. Clean water was used for on-site cleaning, and the operation process is as follows: Step 1: Shutdown and Isolation. The operator stops the rotary jet injection and slurry suction, confirms according to the construction plan that the existing hole-side discharge conditions on site meet the shutdown and isolation requirements, and closes the hole-side isolation valve 1 and the cleaning-side isolation valve 3. Connect the remote sewage discharge assembly 7 to the collection container, check the vent of the buffer tank and the remaining receiving space, and confirm that the pressure relief valve outlet is not blocked.

[0047] Step 2: Check the isolation. Slowly open the drain valve and observe the actual liquid discharge from isolation detection chamber 2 and the drop in the pressure detection component 4 reading. Then close the drain valve and record the chamber pressure within the observation time determined on-site. If the orifice status is known, there is an effective pressure differential, and no abnormalities are observed, place the pressure limiting valve in the low-pressure position and briefly start the cleaning pump; confirm that water is flowing out from the remote end and the chamber pressure does not rise with the water supply before proceeding with cleaning. If any condition is not met, stop immediately and do not continue to increase the pressure to attempt to pass the check.

[0048] Step 3, pressure-limited cleaning. Supply water according to the confirmed pressure setting, keeping the drain assembly 7 open. The operator should simultaneously observe the pressure in the detection chamber, the cleaning inlet pressure, and the distal drain. When the discharged material gradually decreases from a large number of particles to fewer particles and the draining is continuous, cleaning can be stopped for inspection. Extending the cleaning time should not replace observation.

[0049] Step 4: Shutdown and Pressure Relief. At the end of the normal operation, stop the cleaning pump and close the liquid supply shut-off valve. Manually open the pressure relief valve to allow residual water to flow into the buffer tank. If drainage is suddenly obstructed or pressure rises during cleaning, repeat the same step earlier. The pump control circuit will be cut off when the pressure switch reaches the shutdown value, and the pressure relief valve will automatically release pressure when it reaches the opening value. Both isolation valves must remain closed at all times. After troubleshooting, restart from the isolation check; automatic resuming of cleaning is not allowed.

[0050] Step 5, Resume Slurry Return. Confirm that the residual pressure at the inlet and any potentially closed sections has been released. Close the drain valve of isolation detection chamber 2, disconnect the cleaning water supply branch, and switch the sewage discharge assembly 7 to the normal slurry collection destination. Slowly open the cleaning-side isolation valve 3 and the orifice-side isolation valve 1. After checking that there are no leaks at the interfaces and that the slurry destination is correct, resume the jet grouting operation according to the construction plan.

[0051] The above specific embodiments further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A high-pressure rotary jet slurry return pipe pressure limiting and isolation cleaning system, characterized in that, The system includes an isolation assembly, a pressure detection assembly, a pressure-limiting cleaning assembly, a pressure relief buffer assembly, and a sludge discharge assembly. The isolation assembly comprises a hole-side isolation valve, an isolation detection chamber, and a cleaning-side isolation valve connected sequentially along the slurry return direction. The outlet of the cleaning-side isolation valve is connected to the inlet of the slurry return pipe section to be cleaned. The sludge discharge assembly includes a sludge discharge valve, a sludge discharge pipe, and a collection container. The sludge discharge valve is connected to the collection container via the sludge discharge pipe and then connected to the distal end of the slurry return pipe section to be cleaned. The pressure detection assembly is connected to both the isolation detection chamber and the slurry return pipe section to be cleaned. The pressure-limiting cleaning assembly includes a cleaning pump, a pressure limiting valve, and a check valve. The outlet of the cleaning pump is connected to the slurry return pipe section downstream of the cleaning-side isolation valve via a supply shut-off valve, a pressure limiting valve, and a check valve. The check valve's conduction direction is towards the slurry return pipe section to be cleaned. The pressure relief buffer assembly includes a pressure relief valve and a buffer tank. The inlet of the pressure relief valve is connected to the slurry return pipe section to be cleaned, and its outlet is connected to the buffer tank via a pressure relief pipe. The isolation detection chamber is also connected to the buffer tank via an independent drain pipe with a drain valve.

2. The high-pressure rotary jet slurry return pipe pressure limiting and isolation cleaning system according to claim 1, characterized in that, The isolation detection chamber is a short pipe cavity connected to the orifice-side isolation valve and the cleaning-side isolation valve at both ends by flanges. The cavity is equipped with a pressure port and a discharge port. The pressure detection assembly includes a pressure gauge or pressure sensor installed on the pressure port, and a pressure switch connected to the slurry return pipe section to be cleaned. The normally closed contact of the pressure switch is connected in series with the contactor control circuit of the cleaning pump.

3. The high-pressure rotary jet slurry return pipe pressure limiting and isolation cleaning system according to claim 1, characterized in that, The pressure limiting valve is a pressure reducing valve with a pressure regulating element, and the cleaning pump is a water pump with flow-stopping and pressure-limiting characteristics or a return-flow pressure limiting valve is installed at its outlet.

4. The high-pressure rotary jet slurry return pipe pressure limiting and isolation cleaning system according to claim 1, characterized in that, The pressure relief valve is a spring-loaded pressure relief valve with a manual opening mechanism. The buffer tank is equipped with a vent and a drain port. The pressure relief pipe and the independent drain pipe are connected from the top of the buffer tank. An air gap is left between the outlet of each pipe and the highest allowable liquid level of the buffer tank. The two pipes are not connected to each other before they are connected to the buffer tank.

5. A method of using a high-pressure rotary jet slurry return pipe pressure limiting and isolation cleaning system, characterized in that, Includes the following steps: Step 1, shutdown and isolation: Stop the rotary jet injection and slurry return suction. After confirming the discharge conditions on the hole side, close the hole side isolation valve and the cleaning side isolation valve, and connect the far end of the slurry return pipe section to be cleaned to the sewage discharge assembly. Step 2, check the isolation: Open the drain valve of the isolation detection chamber, check the actual drain and pressure drop, close the drain valve and read the chamber pressure change within the predetermined observation time; under the condition that the orifice side pressure is known and there is a distinguishable pressure difference with the chamber pressure, and the chamber pressure change does not exceed the preset range, supply water to the slurry return pipe section to be cleaned at low pressure for a short time, and check the chamber pressure and the remote drain at the same time. Water supply shall be stopped if any abnormality is found or if the conditions for inspection are not met. Step 3, pressure limiting cleaning: After the inspection is passed, adjust the pressure limiting valve to the predetermined cleaning pressure, start the cleaning pump, and supply water to the slurry return pipe section to be cleaned through the check valve. Keep the sewage discharge component connected and observe the chamber pressure, cleaning pressure and drainage status. Step 4, Shutdown and Pressure Relief: When cleaning is completed or abnormal chamber pressure, excessive cleaning pressure, or obstructed drainage occurs, stop the cleaning pump and close the liquid supply shut-off valve. Discharge the residual medium to the buffer tank through the pressure relief valve and keep both isolation valves closed. Step 5, restore slurry return: Confirm that the residual pressure in the cleaning pipeline has been released and the abnormality has been eliminated, exit the cleaning liquid supply branch, close the drain valve, switch the drain end back to the normal slurry return direction, slowly open the cleaning side isolation valve, and then slowly open the orifice side isolation valve to check the connection and slurry return status.

6. The method of using a high-pressure rotary jet slurry return pipe pressure limiting and isolation cleaning system according to claim 5, characterized in that, In step two, compare the pressure readings with the actual liquid discharge before and after discharge; if no actual liquid discharge is observed, the pressure reading does not change with the discharge, or the cavity pressure continues to rise after closing the discharge valve, stop the inspection and clean the pressure interface or repair the isolation valve; if the cavity pressure rises with the cleaning side pressure during low-pressure water supply, or if there is no discharge at the remote end, stop the water supply.

7. The method of using a high-pressure rotary jet slurry return pipe pressure limiting and isolation cleaning system according to claim 5, characterized in that, In step three, the set pressure of the pressure limiting valve is lower than the stop pressure of the pressure switch, and the opening pressure of the pressure relief valve is higher than the stop pressure of the pressure switch; all set values, along with the corresponding action deviations and pressure surges, do not exceed the allowable working pressure of the connected pipe fittings.

8. The method of using a high-pressure rotary jet slurry return pipe pressure limiting and isolation cleaning system according to claim 5, characterized in that, In step four, when the cleaning pressure reaches the shutdown pressure of the pressure switch, the pressure switch disconnects the contactor control circuit of the cleaning pump. After the liquid supply stops, manually open the pressure relief valve to release the residual pressure below its automatic opening pressure. Before resuming operation, check the pressure at the inlet of the slurry return pipe section to be cleaned and the pressure in the pipe section that may be blocked by blockages.

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