A non-stop valve system for city gas pipeline network

Abstract

The utility model discloses a disc type plugging unit one, disc type plugging unit two, balance hole unit one, balance hole unit two, bag type plugging unit one and bag type plugging unit two are set on the upstream pipeline and downstream pipeline of the valve to be replaced, and the disc type plugging unit one, balance hole unit one and bag type plugging unit one are set on the upstream pipeline of the valve to be replaced from far to near, and the disc type plugging unit two, balance hole unit two and bag type plugging unit two are set on the downstream pipeline of the valve to be replaced from far to near. The utility model discloses through optimizing plugging structure and operation process, significantly reduces the project cost, shortens the valve replacement construction operation time, improves the safety of the under pressure operation, avoids the natural gas leakage risk. Through the actual project verification, the system can save the investment nearly million, reduces the influence of the gas supply to the downstream user, has the remarkable economic benefit and social benefit, provides the reliable technical solution for the city gas pipe network safety renewal.

Description

Technical Field

[0001] This utility model relates to the technical field of gas pipeline construction equipment, and in particular to a non-stop valve replacement system for urban gas pipeline networks. Background Technology

[0002] As a core infrastructure for maintaining energy security in modern cities, the reliability of urban gas pipeline networks is closely linked to public safety, people's livelihood, and economic development. Traditional valve replacement work requires gas outages, which not only interrupts gas supply to users and causes significant socio-economic losses, but also falls far short of the current high standards of urban operational resilience requirements. Utility Model Content

[0003] The technical problem to be solved by this utility model is to provide a valve replacement system that can replace valves in urban gas pipelines without interrupting gas supply. This system has fewer operation steps, reduces operation time, and ensures the continuity and stability of energy supply.

[0004] The technical solution provided by this utility model is: a non-stop valve replacement system for urban gas pipeline networks, comprising a disc-type plugging unit, a balancing orifice unit, and a bladder-type plugging unit installed on the upstream and downstream pipelines of the valve to be replaced; the disc-type plugging unit includes disc-type plugging unit one and disc-type plugging unit two; the balancing orifice unit includes balancing orifice unit one and balancing orifice unit two; the bladder-type plugging unit includes bladder-type plugging unit one and bladder-type plugging unit two; wherein plugging unit one, balancing orifice unit one, and bladder-type plugging unit one are arranged sequentially from the farthest to the nearest point on the upstream pipeline of the valve to be replaced, and plugging unit two, balancing orifice unit two, and bladder-type plugging unit two are arranged sequentially from the farthest to the nearest point on the downstream pipeline of the valve to be replaced. The plugging units achieve pressurized plugging of the pipeline, the balancing orifice unit achieves pressure balancing and gas discharge and nitrogen replacement, the bladder-type plugging unit provides secondary sealing protection, and the valve unit completes valve replacement and system restoration.

[0005] Disc-type plugging unit one and disc-type plugging unit two are identical in structure. Disc-type plugging unit one and disc-type plugging unit two respectively include a tee welded to the pipeline, a plugging clamp valve, a plugging connector, a plugging device, and a disc-type plugging device. The disc-type plugging device is installed inside the main pipe of the tee, the plugging clamp valve is connected to the branch pipe of the tee, the plugging connector is connected to the plugging clamp valve, and the plugging device is connected to the plugging connector. The plugging device is detachable, and the disc-type plugging device is removable.

[0006] The first and second balance hole units are identical in structure. The first and second balance hole units respectively include a pressure balancing sub and a balance valve. The balance valve is connected to the pipeline through the pressure balancing sub.

[0007] The first and second bladder-type plugging units are identical in structure, each comprising an isolation bladder perforated section, an isolation bladder flat valve, and an isolation bladder. The isolation bladder is installed inside the pipeline via the isolation bladder perforated section, and the isolation bladder flat valve is connected to the pipeline via the isolation bladder perforated section. The isolation bladder is inflatable, deflated, and removable.

[0008] A valve unit is installed at the location of the valve to be replaced in the pipeline to replace the valve. The valve unit is a valve with a sleeve that matches the upstream and downstream pipelines. Beneficial effects

[0009] 1. This utility model, through a dual sealing structure consisting of a disc-type plug and a bladder-type plug, effectively improves the safety of live-line operations and avoids the risk of natural gas leakage; 2. The adoption of a balance hole design enables safe discharge, nitrogen replacement, and pressure balance, reducing operational risks; 3. The new valve features a custom-designed sleeve that seamlessly connects with the existing pipeline, reducing work steps, shortening the construction cycle, and minimizing pipeline welds; 4. It avoids the impact of traditional gas outage operations on residential and industrial users, resulting in significant social benefits. Attached Figure Description

[0010] Figure 1 This is a schematic diagram of a natural gas pipeline and the valves to be replaced.

[0011] Figure 2 This is a schematic diagram of the structure of this utility model. Detailed Implementation

[0012] The present invention discloses a non-stop gas pipeline switching valve system for urban gas pipeline networks, the specific implementation of which is as follows: I. System Composition This system mainly consists of a disc-type plugging unit, a balance hole unit, a bladder-type plugging unit, and a valve unit.

[0013] Figure 1 Valve 1, awaiting replacement, is located on natural gas pipeline R. (Example:) Figure 2As shown, the disc-type plugging unit, the balancing hole unit, and the bladder-type plugging unit of this utility model are installed on the upstream and downstream pipelines of the valve to be replaced 1. Among them, the disc-type plugging unit P1, the balancing hole unit H1, and the bladder-type plugging unit L1 are installed in sequence from far to near the valve to be replaced on the upstream pipeline of the valve to be replaced, and the disc-type plugging unit P2, the balancing hole unit H2, and the bladder-type plugging unit L2 are installed in sequence from far to near the valve to be replaced on the downstream pipeline of the valve to be replaced (for example, the disc-type plugging unit P1, the balancing hole unit H1, and the bladder-type plugging unit L1 are symmetrically installed on the upstream and downstream pipelines of the valve to be replaced, along with the disc-type plugging unit P2, the balancing hole unit H2, and the bladder-type plugging unit L2). The valve unit is a new valve with a custom-made sleeve, and the sleeve is matched according to the specifications of the old pipeline.

[0014] The disc-type plugging unit (disc-type plugging unit one P1 or disc-type plugging unit two P2) includes a tee 5 welded to the pipeline, a plugging clamp valve 4, a plugging connector 3, a plugging device 2, and a disc-type plugging device 6. The disc-type plugging device is installed inside the main pipe of the tee, the plugging clamp valve is connected to the branch pipe of the tee, the plugging connector is connected to the plugging clamp valve, and the plugging device is connected to the plugging connector. The plugging device 2 is detachable, and the disc-type plugging device 6 is removable. See details. Figure 2 .

[0015] The balancing orifice unit (balancing orifice unit one H1 or balancing orifice unit two H2) includes a pressure balancing sub-section 7 and a balancing valve 8, the balancing valve being connected to the pipeline via the pressure balancing sub-section. See details. Figure 2 .

[0016] The bladder-type plugging unit (bladder-type plugging unit one L1 or bladder-type plugging unit two L2) includes an isolation bladder perforated section 9, an isolation bladder flat valve 10, and an isolation bladder 11. The isolation bladder is installed inside the pipeline through the isolation bladder perforated section, and the isolation bladder flat valve is connected to the pipeline through the isolation bladder perforated section. The isolation bladder is inflatable, deflated, and removable; see details. Figure 2 .

[0017] The valve unit consists of a new valve 12 and a custom-made sleeve 13 to match the old piping; see details. Figure 2 .

[0018] II. Operating Procedures 1. Welding tees and short sections According to the locations shown in the diagram, weld the sealing tee (the clamp valve and sealing connector need to be prefabricated and installed on the sealing tee) at 3.5 meters, 2.5 meters, and 1.5 meters upstream and downstream of the existing valve, respectively. Weld the pressure balancing short section (the balancing valve is a DN50 ball valve, which is prefabricated and installed on the short section) and the isolation bladder opening short section (the isolation bladder flat valve is prefabricated and installed on the short section).

[0019] 2. Hole sealing 2.1 Drill a balance hole, specification DN50 Assemble the T-101B drilling machine Install the T-101B drilling machine onto the balance valve and conduct a pressure test on the whole unit. The test pressure should be the operating pressure in this section of the pipeline.

[0020] Inspect the mating surfaces between valves for leaks; perform balancing hole opening operations.

[0021] After drilling is completed, close the ball valve and remove the drilling machine.

[0022] 2.2 Opening and plugging the hole Replace the hole-opening connector and install the sealing tool and guide drill.

[0023] Install the hole puncher onto the sealing clamp valve.

[0024] Use nitrogen to perform an overall pressure test on the hole-opening machine and the hole-opening valve. The test pressure should be the operating pressure inside that section of the pipeline.

[0025] Check for leaks at the joints between valves.

[0026] After drilling is completed, close the clamp valve and dismantle the drilling machine.

[0027] 2.3 Open the lower sac opening, the procedure is the same as in 2.2. 3. Sealing with pressure plate 3.1 Assemble the plugging device and install the disc plugging device onto the plugging device.

[0028] 3.2 Use nitrogen to perform an overall pressure test on the sealing equipment. The test pressure should be the operating pressure inside that section of the pipeline.

[0029] 3.3 Inspect the joint surfaces between valves for leaks.

[0030] 3.4 Pipeline plugging: First, install the downstream plug head in the opposite direction of the airflow, then install the upstream plug head in the direction of the airflow.

[0031] 3.5 Verify the blocking effect.

[0032] The natural gas in the blocked isolation pipe section is vented through the balance hole, and the pressure is reduced by about 0.1 MPa. If the pressure in this isolation pipe section no longer rises and there is no leakage sound at the sealing part, continue to reduce the pressure. When the pressure is zero and no more natural gas flows out, it means that the sealing is successful; otherwise, it means that there is a leak in the sealing, and the sealing head needs to be lifted for inspection and then resealed.

[0033] 3.6 Venting and replacement of the blocked section The natural gas in the blocked section was vented through the balance holes at both ends, and an isolation and warning zone was established around the venting point. After venting, nitrogen was injected into the downstream balance hole, and the concentration of combustible gas was measured at the upstream balance hole using a combustible gas detector three times consecutively.

[0034] 4. Encapsulation The isolation bladder is lowered through the lower bladder hole and pressurized with nitrogen to 0.02 MPa. Throughout the operation, 24-hour monitoring is required to observe pressure changes within the bladder. If a pressure drop is detected, the bladder must be replenished immediately, maintaining a constant pressure of 0.02 MPa. The function of the isolation bladder is to provide a bladder-like seal for the pipeline, isolating flammable gases outside the welding area. If slight leakage occurs during the disc-type sealing, the flammable gas between the disc and bladder seals is diverted through the balance hole, thereby enhancing operational safety.

[0035] 5. Replace valve 5.1 Determine the pipe break location based on the dimensions of the customized valve unit (slightly larger than the original valve size), cut the pipe mechanically, and lift the removed pipe and valve away from the construction site; 5.2 Weld the new valve with sleeve to the old pipe; 5.3 After welding is completed, non-destructive testing is performed on the weld to confirm that the weld is qualified.

[0036] 6. Release the bladder-type occlusion After the weld inspection is passed, the bladder plug is removed, and the plug handle is manually lowered into the bladder hole to cover the blind plate.

[0037] 7. Nitrogen purging of the sealing section Connect the nitrogen injection pipeline to the upstream balance hole and inject nitrogen gas to replace the nitrogen in the blocked section of the pipeline. Exhaust gas and test at the downstream balance hole of the blockage point. When the oxygen content is less than 2%, it is considered qualified.

[0038] 8. Pipeline pressure balance After the replacement operation is completed, connect the upstream balance hole to the upstream plug using a balance hose, slowly open the valve to inject natural gas, use natural gas to purge the nitrogen in the connecting pipeline, and check the concentration of combustible gas at the downstream balance hole. When the natural gas content exceeds 90%, close the downstream balance hole valve and observe the pressure value through the pressure gauge of the plug until the pressure value is equal to the pipeline operating pressure, at which point the balancing is complete.

[0039] 9. Remove the seal, install the plug handle and blind flange. After the gas injection balance is completed, the plugging operation is carried out. The principle of plugging is to raise the upstream first and then the downstream, open the main pipeline, remove the plug, close the clamp, and install the plug handle and blind flange.

[0040] III. Handling Special Working Conditions Application in cold regions: The buried part of the pressure pipe above the frozen soil layer and the above-ground part should be insulated with 40mm thick silicate roll insulation.

[0041] Corrosion protection requirements: Any damage to the pipeline's anti-corrosion coating during the operation shall be repaired in accordance with relevant specifications.

[0042] Safety monitoring: During the operation, combustible gas detectors are continuously used to monitor the gas content in the pit to ensure that the operation is within a safe range.

[0043] IV. Acceptance Standards All butt welded joints shall be subjected to 100% radiographic testing, and the results shall meet the Class II standard in NB / T 47013.2-2015.

[0044] The fillet welds shall be subjected to penetrant testing, and the results shall meet the Class I standard in NB / T 47013.5-2015.

[0045] After the system is installed, it should be subjected to strength and tightness pressure tests along with the process piping. The ball valve should not be shut off during the pressure test.

[0046] Through the above-described embodiments, this utility model enables the replacement of urban gas pipeline valves without interrupting gas supply. The valve unit, through the customization of new valves with sleeves, reduces operational steps, ensures the continuity and stability of energy supply, and has significant economic and social benefits.

Claims

1. A non-stop gas pipeline switching valve system for urban gas pipeline networks, characterized in that: It includes disc-type plugging units, balance hole units, and bladder-type plugging units installed on the upstream and downstream pipelines of the valve to be replaced; the disc-type plugging unit includes disc-type plugging unit one and disc-type plugging unit two; the balance hole unit includes balance hole unit one and balance hole unit two; the bladder-type plugging unit includes bladder-type plugging unit one and bladder-type plugging unit two; wherein disc-type plugging unit one, balance hole unit one, and bladder-type plugging unit one are installed in order from farthest to near the valve to be replaced on the upstream pipeline of the valve to be replaced, and disc-type plugging unit two, balance hole unit two, and bladder-type plugging unit two are installed in order from farthest to near the valve to be replaced on the downstream pipeline of the valve to be replaced.

2. The uninterrupted gas pipeline switching valve system for urban gas pipeline networks according to claim 1, characterized in that: Disc plugging unit one and disc plugging unit two respectively include a tee welded to the pipeline, a plugging clamp valve, a plugging connector, a plugging device, and a disc plugging device; wherein, the disc plugging device is installed in the main pipe of the tee, the plugging clamp valve is connected to the branch pipe of the tee, the plugging connector is connected to the plugging clamp valve, and the plugging device is connected to the plugging connector.

3. The uninterrupted gas pipeline switching valve system for urban gas pipeline networks according to claim 1, characterized in that: The first and second balance hole units respectively include a pressure balancing sub and a balance valve, with the balance valve connected to the pipeline via the pressure balancing sub.

4. The uninterrupted gas pipeline switching valve system for urban gas pipeline networks according to claim 1, characterized in that: The first and second bladder-type plugging units respectively include an isolation bladder opening section, an isolation bladder flat valve, and an isolation bladder. The isolation bladder is installed inside the pipeline through the isolation bladder opening section, and the isolation bladder flat valve is connected to the pipeline through the isolation bladder opening section.

5. The uninterrupted gas pipeline switching valve system for urban gas pipeline networks according to claim 1, characterized in that: A valve unit is installed at the location of the valve to be replaced in the pipeline to replace the valve. The valve unit is a valve with a sleeve that matches the upstream and downstream pipelines.

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