Abstract: This article analyzes the problems existing in the installation and construction of the top-mounted magnetic flap level gauge in an all-round way, and briefly introduces the importance of strengthening the installation and construction of the top-mounted magnetic flap level gauge, and proposes the top-mounted magnetic flap level gauge The preparation content before installation, such as organizing pipeline installation technicians to familiarize themselves with drawings, do a good job in the measurement and control network calibration work, conduct a comprehensive inspection of the pipeline, etc., propose the installation and construction points of the top-mounted magnetic flap level gauge, and hope to provide relevant personnel Good help.
In recent years, due to the continuous expansion of the construction scale of various projects in our country, the application range of top-mounted magnetic flap level gauges has become more and more extensive. Reasonable installation of the top-mounted magnetic flap level gauge can ensure the stable operation of the pipeline and prolong the service life of the pipeline. In order to ensure the effective improvement of the installation and construction quality of the top-mounted magnetic flap level gauge, the article focuses on the main points of the installation and construction of the top-mounted magnetic flap level gauge.
1. Project overview
The main pipelines of this contract project are 3 DN3600 and 4 DN3200 PCCP pipes or steel pipes, pile numbers C055+1 18～C058+500 are 3 DN3600 pipes, the line length is 3.382km, of which the PCCP pipe section is 3.260km long , The length of the steel pipe section is 0.1 to 22km. See Table 1 for the key equipment and equipment for the installation of the top-mounted magnetic flap level gauge on this section.
Second, the preparation work before installation of the top-mounted magnetic flap level gauge
(1) Organize pipeline installation technicians to be familiar with drawings
The construction unit needs to clarify the installation and construction technology to the technicians, so that they are familiar with the various technical indicators and performance of the PCCP pipe, as well as the pipeline layout along the construction section and the location of other buildings. Make technical clarifications to the installation workers, lifting workers, drivers and safety personnel who participate in the pipeline installation, so that each construction worker understands his own responsibilities and pipeline installation standards and precautions.
(2) Do a good job in the measurement and control network calibration and material quality control
According to the control point plane and elevation parameters introduced by the measurement and control network, the bottom of the trench is measured by reliable methods, and the gantry plate, level, special ruler, etc. are used for grading and line setting, and the plane position and slope of the pipeline can also be measured inside the pipeline. During installation and construction, the measurement and control network is checked regularly. Grasp the planning and implementation of materials and equipment, and deliver them to the site in time to ensure smooth installation. All materials in this contract, including equipment and related construction technology, need to be implemented in accordance with the technical standards issued by the country and the industry. If the content of the technical terms is inconsistent with the specifications cited in the project, the technical terms and regulations need to be in accordance with the supervision engineer’s Instruction to select.
(3) Conduct a comprehensive inspection of the pipeline
After the groove and cushion pass the acceptance, the pipe can be suspended into the groove. It is strictly forbidden to have underwater pipes in the groove. When the pipeline foundation is the undisturbed soil layer, the open arc method or the arc fill method is used. When the arc fill method is used, the support part of the pipeline should be tamped to the compactness required by the design before placing the pipeline. No matter what excavation method is adopted, the arc surface should be consistent with the arc surface of the pipeline. The rock base section should be dug down to 0.2m below the bottom of the pipe according to the design drawings, and then backfilled with gravel or medium-coarse sand to reach the elevation of the bottom of the pipe, and the degree of compaction should meet the requirements of the design documents [1].
Third, the main points of the installation and construction of the top-mounted magnetic flap level gauge
(1) Key points of measurement control
Before the construction of the top-mounted magnetic flap level gauge, the relevant operators must conduct a comprehensive measurement of the centerline of the pipeline, including its corners, and close it within the specified error range. The center line of the pipeline should be spaced at a certain interval, and the corresponding center piles should be set up. Center-line turning and different types of structures need to be set up with center piles to ensure that the setting of building control piles is more reasonable. Before the pipeline burying facility works, the operators should arrange the corresponding temporary leveling points along the pipeline’s burying direction, and do a good job of fixing the leveling points. The leveling points need to be set on a relatively solid ground to ensure the elevation of the various construction pipelines. Get efficient control.
The actual installation position of the pipeline should be consistent with the installation and piping diagram of the pipeline. During the construction process, the position deviation of the turning point of the pipeline and the starting and ending points of the pipeline curve section should be strictly controlled. The deviation of the intersection of the pipeline and the building should meet the design requirements, and the direction and slope deviation of the pipeline installation should meet the requirements of the specifications and the technical provisions of the bidding documents.
(2) Key points of down-pipe, pipe-laying and hoisting construction
After the acceptance of the base cushion is qualified, the top-mounted magnetic flap level gauge is hoisted into the foundation pit by the crawler crane on each working surface, and the nylon belt sling is used for hoisting. When lowering the pipe, the position of the crawler crane shall not affect the stability of the side slope of the pipe ditch, and no one shall stay under the working surface of the trench. The lower pipe should make the pipe roughly in place at one time, avoiding multiple handling and moving of the pipe in the trench. When working near high-voltage transmission lines, the safe distance between the crawler crane and the line should comply with the regulations of the electrical industry management department. When the pipeline runs into the trench, it must not collide with the trench wall and the pipeline under the trench.
The crawler sling tube of each working surface is used in the trough, and the cloth tube is hoisted by the nylon belt sling. When arranging or moving pipes, ensure that the pipes are suspended. The lifting height of the pipes should not be less than 10cm. The pipes should not be dragged or towed at the bottom of the ditch, and should not be hit or attempted to move the pipes with the shovel head of an excavator. PCCP pipes with two pipes in the same slot are installed simultaneously with two pipes; PCCP pipes with three pipes in the same slot are installed twice. 100m is an installation unit, and the pipes are installed in sequence; the PCCP pipes with four pipes in the same slot are installed twice. The first time two pipes are 100m long, and the other two pipes are installed at the second time, each 100m is One installation unit for pipe installation in turn. Pipeline backfilling begins construction after all the pipelines are installed [2].
(Three) Clean the pipe joints and the installation points of the sealing rubber ring
Lift the pipe and do the corresponding mobile installation work. After moving to the designated location, all kinds of soil and dirt inside the socket and outside the socket need to be cleaned up. After cleaning, the dust inside the pipe needs to be completely cleaned. Clean up. When cleaning the pipe sockets and sockets, ensure that the working surface is smoother and there can be no foreign objects. If flash or burrs are found, they must be treated immediately. A layer of lubricating oil should be applied to the pipe sockets and sockets, and food-grade vegetable lubricating oil should be used as much as possible. Petroleum-type lubricating oil is prohibited.
First lubricate the rubber ring with edible vegetable oil, then put the rubber ring into the groove of the socket ring, and then use a short rod to insert under the rubber ring and turn around the whole pipe mouth 2 to 3 times to adjust the rubber ring tightness and make the rubber ring evenly Sleeve into the groove of the socket ring without distortion or overturning. If the rubber ring is found to be distorted during installation, it should be immediately exited and reinstalled. After the rubber ring is installed, apply a layer of food-grade vegetable lubricant on its outer surface.
(4) Key points of pipeline butt installation and construction
Firstly, the reference pipe should be leveled and aligned strictly according to the design requirements of the installation height and position, and then accurately positioned, and then the pipe to be docked is lifted with the installation crawler crane, and pushed to the vicinity of the installed pipe opening for joint cleaning and rubber ring installation. The installation should start from the downstream, with the socket facing the forward direction of the installation. When butting, keep the socket end and the socket end parallel, and make the surrounding clearance approximately equal. The pipeline installation adopts the internal pull method, and the installation gap is controlled within the scope of the installation requirements of the pipe factory. During the connection process, if it is found that the rubber ring enters the working surface unevenly, exit the installation pipe in time, check the damage of the rubber ring, if it is damaged, replace the rubber ring and reinstall it [3].
The method of installing pipe fittings by internal pulling: After the first section of the pipe fittings is firmly positioned, set up special equipment for internal pulling installation, and the crawler crane will lift the pipe fittings, and timely do the cleaning and inspection work. Use the crawler crane to connect the sockets of the pipe fittings and use the internal pulling machine. A pulling force is generated to make the socket of the tube to be installed enter the socket of the installed tube. After the axis is centered and aligned, install the inner pulling device and remove the supporting square timber. Use the inner pulling device to slowly approach the socket of the pipe to be installed and slowly enter the socket of the pipe in place until the specified installation gap is reached. . For the straight section, the installation gap should be controlled within the range of 25+3～25-10mm. If the foundation of the pipeline is in an uneven state, the operator must strictly inspect its internal gap to keep its internal gap not exceeding 28mm. If there is a corner at the pipe joint, the minimum value between the two joints cannot be less than 15mm [4].
(5) Pipeline suppression test
If there is leakage or the pressure cannot be maintained, it should be dismantled and reinstalled. When reinstalling, check whether the rubber ring is damaged. If it is damaged, it must be replaced and pressed again until it is qualified. In addition, the testers also need to carry out the pipeline water pressure test. The pipeline water pressure test process is shown in Figure 1.
Fourth, the conclusion
In summary, through scientific analysis of the key points of installation and construction of top-mounted magnetic flap level gauges, such as measurement control key points, down pipe, pipe laying and lifting construction key points, clean pipe joints and sealing rubber ring installation key points, pipeline docking installation key points , Pipeline pressure test, etc., can ensure that the quality of the installation and construction of the top-mounted magnetic flap level gauge is better improved.
Post time: 27-09-21