CN113202974B - Overlap-connection method for long-distance nodular cast iron pipeline subsection construction - Google Patents
Overlap-connection method for long-distance nodular cast iron pipeline subsection construction Download PDFInfo
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- CN113202974B CN113202974B CN202110610179.2A CN202110610179A CN113202974B CN 113202974 B CN113202974 B CN 113202974B CN 202110610179 A CN202110610179 A CN 202110610179A CN 113202974 B CN113202974 B CN 113202974B
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- 229910001141 Ductile iron Inorganic materials 0.000 title claims abstract description 129
- 238000010276 construction Methods 0.000 title claims abstract description 60
- 238000000034 method Methods 0.000 title claims abstract description 47
- 238000003780 insertion Methods 0.000 claims description 10
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- 230000008569 process Effects 0.000 description 11
- 230000002706 hydrostatic effect Effects 0.000 description 10
- 238000009434 installation Methods 0.000 description 9
- 238000003032 molecular docking Methods 0.000 description 6
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- 238000000498 ball milling Methods 0.000 description 2
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- 239000007788 liquid Substances 0.000 description 2
- 230000001050 lubricating effect Effects 0.000 description 2
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- 229910000831 Steel Inorganic materials 0.000 description 1
- 230000002159 abnormal effect Effects 0.000 description 1
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- 238000004140 cleaning Methods 0.000 description 1
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- 238000003911 water pollution Methods 0.000 description 1
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
- F16L1/00—Laying or reclaiming pipes; Repairing or joining pipes on or under water
- F16L1/024—Laying or reclaiming pipes on land, e.g. above the ground
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
- F16L1/00—Laying or reclaiming pipes; Repairing or joining pipes on or under water
- F16L1/024—Laying or reclaiming pipes on land, e.g. above the ground
- F16L1/06—Accessories therefor, e.g. anchors
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Abstract
The invention provides a connection method for segmental construction of a long-distance nodular cast iron pipeline, which comprises the following steps: step S1, an elbow is installed, and two end parts of the elbow are respectively C1Point and C2A first operation surface and a second operation surface are simultaneously developed on two sides of the elbow, the nodular cast iron pipeline in the first operation surface is installed to the point A, and the nodular cast iron pipeline in the second operation surface is installed to the point B and both face the elbow for a certain distance; step S2, starting construction from point B in the second working plane to the elbow, installing BC2Segment of nodular cast iron pipe, make BC2The section pipeline is connected with the elbow; step S3, calculating and cutting the AC needing connection in the first working face1Length of the segment pipe; step S4, deflecting BC connected to the elbow in the second working plane2Pipe cutting, and mixing AC1The section pipeline is connected with the pipeline and the elbow in the first working face well, and the connection of two pipeline sections at the elbow is completed. The invention can realize the connection of the pipeline at the elbow.
Description
Technical Field
The invention belongs to the technical field of pipeline overlap joint, and particularly relates to an overlap joint method for long-distance nodular cast iron pipeline segmental construction.
Background
In the construction of the long-distance nodular cast iron pipeline, in order to accelerate the construction progress, the construction side needs to adopt subsection construction, so the connection between the subsection pipelines becomes a big problem. At present, a subsection construction connection point is usually arranged at a position with an expansion joint, and a construction working face adopting expansion joint connection can only be disconnected at a straight line and can not be disconnected at an elbow, so that the development of the pipeline connection construction working face is greatly limited.
Therefore, there is a need to provide an improved solution to the above-mentioned deficiencies of the prior art.
Disclosure of Invention
The invention aims to provide a connection method for segmental construction of a long-distance ductile cast iron pipeline, which aims to solve the problem that the existing connection method adopting a telescopic head can only be disconnected at a straight line and can not be disconnected at an elbow, so that the development of a pipeline connection construction working face is limited.
In order to achieve the above purpose, the invention provides the following technical scheme:
a connection method for segmental construction of a long-distance nodular cast iron pipeline comprises the following steps:
step S1, an elbow is installed, and two end parts of the elbow are respectively C1Point and C2A first operation surface and a second operation surface are simultaneously developed on two sides of the elbow, the ductile iron pipeline in the first operation surface is installed to the point A, the pipeline in the second operation surface is installed to the point B, and a distance is reserved towards the elbow;
step S2, starting construction from point B in the second working plane to the elbow, installing BC2Segment of nodular cast iron pipe, make BC2The section nodular cast iron pipeline is connected with the elbow;
step S3, calculating and cutting out the AC needing connection in the first working face1The length of the nodular cast iron pipeline;
step S4, deflecting BC connected to the elbow in the second working plane2Segmenting the ductile iron pipeline and mixing AC1The nodular cast iron pipeline section is well connected with the nodular cast iron pipeline and the elbow in the first working surface, and the connection of the two pipeline sections at the elbow is completed.
According to the connection method for the segmental construction of the long-distance nodular cast iron pipeline, as a preferable scheme, the elbow is a 45-degree elbow or a 90-degree elbow.
The connection method for the segmental construction of the long-distance ductile cast iron pipeline is a preferable scheme that AC in the first working plane is defined1The reserved length of the section is Lac, the insertion depth of the nodular cast iron pipeline is b, and then the cut AC is obtained1The length of the section pipeline is Lac +2 b.
As a selection scheme, the Lac value range is 8-12m, and the b value range is 105-115 mm.
According to the overlap-connection method for the segmental construction of the long-distance nodular cast iron pipeline, as a preferable scheme, when the pipe diameter of the nodular cast iron pipe is 200-400mm, the length of the nodular cast iron pipe is L0, the maximum deflection angle of the nodular cast iron pipe is 3 degrees, and the reserved distance L in the second working surface is not less than 2.1+ L0 m.
More preferably, the length L0 of the nodular cast iron pipe is 5.7 mm.
According to the connection method for the segmental construction of the long-distance nodular cast iron pipeline, as a preferable scheme, when the pipe diameter of the nodular cast iron pipe is 700-800mm, the length of the nodular cast iron pipe is L0, the maximum deflection angle of the nodular cast iron pipe is 2 degrees, and the reserved distance L in the second working surface is not less than 3.15+ L0 m.
The connection method for the segmental construction of the long-distance ductile cast iron pipeline preferably comprises the specific operation of step S4, namely, marking the depth on the outer surface of the elbow pipe fitting and then deflecting the elbow pipe fitting to AC1Segment of nodular cast iron pipeline, and deflecting elbow to make its mouth and AC1The pipe openings of the sections are opposite to each other, and the nodular cast iron pipeline in the first working face is connected with the first working faceConnected with the elbow well until the depth mark is completely inserted into the AC1Inside the pipe section.
The overlap-connection method for the segmental construction of the long-distance nodular cast iron pipeline is a preferable scheme, the overlap-connection of the nodular cast iron pipeline is installed by adopting the rubber ring, and the specific operation is that the rubber ring and the pipe orifice on the nodular cast iron pipeline are cleaned, the rubber ring is arranged in the bell mouth groove of the nodular cast iron pipeline, and the rubber ring is tapped to realize the fit between the rubber ring and the pipe orifice.
The overlap-connection method for the segmental construction of the long-distance nodular cast iron pipeline is preferably used for polishing the outer surface of the socket of the nodular cast iron pipeline so as to remove the melting point left after the nodular cast iron pipeline is machined.
According to the overlap connection method for the segmental construction of the long-distance nodular cast iron pipe, as a preferable scheme, a lubricating agent is adopted to lubricate the pipe orifice of the nodular cast iron pipe, so that the pipe connection operation is facilitated.
Has the advantages that:
in the long-distance nodular cast iron pipeline subsection construction process, the elbow pipe fitting is adopted to perform the connection of the subsection pipeline, so that the connection of the pipeline at the elbow can be realized, and more operation surface choices are provided for the pipeline subsection construction. And moreover, because the elbow pipe fitting is adopted for connection, the working surfaces on two sides of the elbow can be simultaneously developed, the construction progress is accelerated, and the smooth and quick completion of the construction process is ensured.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate embodiments of the invention and, together with the description, serve to explain the invention and not to limit the invention. Wherein:
fig. 1 is a schematic view of DN200 ductile iron pipe connection conditions in an embodiment of the present invention;
FIG. 2 is a schematic view of an embodiment of the present invention illustrating the installation of a pipe in the direction i;
FIG. 3 is a schematic diagram of calculating a docked cutting pipeline length in accordance with an embodiment of the present invention;
FIG. 4 shows deflection C of an embodiment of the invention2D section pipeline is connected with AC1A schematic view of a section of a pipeline;
FIG. 5 is a schematic view of the connection of two pipe sections at an elbow according to an embodiment of the present invention;
FIG. 6 is a schematic view of the connection of two pipe sections at the elbow according to the embodiment of the present invention;
FIG. 7 is a schematic view of a completed pipeline docking according to an embodiment of the present invention;
fig. 8 is a schematic view of a pipe docking structure according to embodiment 1 of the present invention;
fig. 9 is a schematic view of a pipe connecting structure according to embodiment 2 of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be described clearly and completely below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments that can be derived by one of ordinary skill in the art from the embodiments given herein are intended to be within the scope of the present invention.
The present invention will be described in detail with reference to examples. It should be noted that the embodiments and features of the embodiments may be combined with each other without conflict.
In the long-distance nodular cast iron pipeline subsection construction process, the elbow pipe fitting is adopted to perform the connection of the subsection pipeline, so that the connection of the pipeline at the elbow can be realized, and more operation surface choices are provided for the pipeline subsection construction. And moreover, because the elbow pipe fitting is adopted for connection, the working surfaces on two sides of the elbow can be simultaneously developed, the construction progress is accelerated, and the smooth and quick completion of the construction process is ensured.
The connection method mainly comprises the step of performing pipeline connection at an elbow of 45 degrees or 90 degrees, and the connection method is described in detail by taking DN200 nodular cast iron pipe connection as an example.
According to the construction condition shown in fig. 1 and fig. 2, the two sides of the 90-degree elbow are respectively provided with a first operation surface for pipeline installation and a second operation surface for pipeline installation, in order to accelerate the construction progress, the construction of the first operation surface and the second operation surface is carried out simultaneously around the 90-degree elbow, and the connection is carried out at the 90-degree elbow after the construction of the two operation surfaces is completed. The specific operation is as follows:
step S1, a 90-degree elbow is installed, and two end parts of the elbow are respectively C1Point and C2A point, a thin rope is adopted to ensure that the axis of the direction j of the first working surface is vertical to the axis of the direction i of the second working surface; simultaneously carrying out construction of a first operation surface and a second operation surface, installing the nodular cast iron pipeline to a point A in the first operation surface, installing the nodular cast iron pipeline to a point B in the second operation surface, and reserving a distance between the point A and the point B and the elbow;
in step S2, construction is started in the i direction from point B on the second working plane, and BC is installed2Segment of nodular cast iron pipe, make BC2The section nodular cast iron pipeline is connected with the elbow;
step S3, calculating and cutting the AC needing connection in the first working face1The length of the nodular cast iron pipeline;
step S4, performing connection, specifically deflecting BC connected with the elbow in the second working plane2Segmenting the ductile iron pipeline and mixing AC1The nodular cast iron pipeline section is well connected with the nodular cast iron pipeline and the elbow in the first working surface, so that the connection of the two pipeline sections at the elbow can be completed.
It should be noted that the reserved distance from the point B to the elbow in the second working plane is generally set to be 8m to 10m, and the standard length of each DN200 nodular cast iron pipe is 5.7m, and then BC is installed2In a segment (refer to fig. 1 to 4), a whole DN200 nodular cast iron pipe (namely, a BD segment pipe) and a cut DN200 nodular cast iron pipe (namely, a C segment pipe) need to be installed2D segment of pipeline), wherein C2The length of the D-section pipeline can be measured according to C2D the distance Lcd between two points, thus cutting out C of corresponding length2D section pipeline. When cutting DN200 ball milling cast iron pipe, C is considered2The insertion depth b of the D-section pipeline is 105mm-115mm (such as 105mm, 106mm, 107mm, 108mm, 109mm, 110mm, 111mm, 112mm, 113mm, 114mm or 115mm) in the common case of the ductile iron pipeline, and then C2The length of the D-section pipeline is Lcd +2b, and C can be obtained by cutting DN200 nodular cast iron pipe2D section pipeAnd (4) carrying out the following steps. When the pipeline is installed in the second working face, the BD segment pipeline is installed firstly, and then the C segment pipeline is installed2And the D-section pipeline is connected with the BD-section pipeline and the 90-degree elbow, so that the pipeline installation in the second working plane can be completed. Furthermore, the C connected with the elbow in the second working surface can be directly deflected when the connection operation is carried out2D section of pipeline and mixing AC1The segment pipeline is well connected with the nodular cast iron pipeline and the elbow in the first working surface, and then the connection of two pipe segments at the elbow can be completed.
As shown in fig. 3 and 4, in an embodiment of the present invention, the specific operation of step S3 is as follows:
measuring out AC by using tape measure1The distance Lac between two points is calculated according to the distance1Length of pipe section, AC1The length of the section pipeline is calculated by adopting a formula Lac +2b, wherein b is the insertion depth of the nodular cast iron pipeline, and DN200 nodular cast iron pipeline insertion depth is 105mm-115 mm. Finally, cutting DN200 nodular cast iron pipes according to the calculated length to obtain AC needing connection1And (5) segmenting the nodular cast iron pipeline.
In the first working plane, point a is connected to elbow C1The reserved distance of the points is generally 8 m-12 m, so that the connection operation can be carried out by adopting a whole DN200 nodular cast iron pipe and the DN200 nodular cast iron pipe obtained by cutting.
When the construction of the first working surface and the second working surface is carried out, the reserved distance needs to be roughly calculated in advance, and the specific calculation process is as follows:
according to the water supply and drainage pipeline engineering construction and acceptance Standard (GB 50268-2008) 5.5.8, the deflection angle of the nodular cast iron pipe is not more than 3 degrees for C2D-section pipe deflecting to ensure AC1Segment pipe connection, then require C2The length L1 of the D-section pipeline is more than or equal to 2.1m (calculated as follows):
then
L1≥2101mm
Wherein b is the insertion depth (mm) of the ductile iron pipe.
Therefore, the reserved distance L is more than or equal to 2.1m +5.7 m-7.8 m (usually 8 m-10 m), wherein 5.7m is the standard length of the whole DN200 nodular cast iron pipe.
As can be known from the calculation process, the reserved distance is related to the maximum deflection angle of the pipeline and the insertion depth of the pipeline, the insertion depths of the pipelines with different pipe diameters are basically the same, but the maximum deflection angles are different, for example, when the maximum deflection angle of a nodular cast iron pipe (according to the specification GB 50268-2008: 5.5.8) with the pipe diameter of 200-400mm is 3 degrees, the L1 is more than or equal to 2101mm, and the reserved distance L is more than or equal to 2.1m +5.7m is more than 7.8 m; the maximum deflection angle of the nodular cast iron pipe (according to the specification GB 50268 + 2008: 5.5.8) with the pipe diameter of 700 + 800mm is 2 degrees, and the L1 is more than or equal to 110/sin2 degrees and is 3152mm, so the reserved distance L is 3.15+5.7 and is 8.85 m.
It should be noted that the reserve length calculation takes into account that the pipe and the 90 degree elbow are an integral deflection, so the reserve length is independent of the pipe elbow size.
As shown in fig. 4-7, in an embodiment of the present invention, in step S4, the specific operation of docking is,
firstly, an oily pen is adopted to make an insertion depth mark on the outer surface of a 90-degree elbow pipe fitting, the general depth mark is red, and then AC is subjected to detection1The pipeline section is deflected (within the range of allowable deflection angle of 3 degrees), and meanwhile, the 90-degree elbow is also deflected, and the hand-operated block is firstly installed with AC1And a 90-degree elbow section, which connects the 90-degree elbow pipe orifice with the AC1The section pipe orifices are opposite, and finally, the nodular cast iron pipeline in the first working face is well connected with the 90-degree bent head by using the manual hoist until the mark is completely inserted into the AC1In the pipe section, the connection operation can be completed.
In the construction process of carrying out segmentation pipeline overlap joint, the on-the-spot installation needs to pay attention to several points:
(1) the axes and the pipeline elevation are well controlled during installation;
(2) the method has the advantages that the connection must ensure the installation quality of the rubber ring, the work of cleaning the rubber ring and the pipe orifice is well done, the adhesive matters (such as dirt, sundries and the like) on the rubber ring and in the pipe orifice are cleaned, the rubber ring is bent into a quincunx shape and is arranged in a bell mouth groove of the nodular cast iron pipeline, and a rubber hammer is used for tapping the rubber ring to ensure that the rubber ring is completely matched with the pipe orifice;
(3) polishing the outer surface of the socket by using a woodworking flat file to remove a melting point left by processing the nodular cast iron pipe and ensure the quality of pipeline connection;
(4) the special pipe orifice lubricant is needed to lubricate the pipe orifice, and the lubricant is well smeared on the inner edge and the outer edge of the pipe orifice and the rubber ring.
In the preferred embodiment of the present invention, the special nozzle lubricant is food oil or cake oil, and soap water, detergent, butter, etc. are not recommended for the following reasons: soap water and liquid detergent are easy to volatilize, and the lubricating effect is usually lost under the condition of high heat or wind, so that the soap water and the liquid detergent are not recommended to be used; butter is the common name of lubricating grease, has the risk of increasing water pollution, and is not recommended to be used.
The connection method for the segmental construction of the long-distance ductile cast iron pipeline is described in detail by the specific embodiment.
The embodiment is a water supply project in a certain city, and mainly comprises a water intake pump station, a newly-built water plant and a matching pipe network, wherein the matching pipe network mainly comprises a 0.3Km steel pipe raw water pipeline, a 2.5KmdN400 nodular cast iron pipe and a 10.1KmdN200 nodular cast iron pipe, wherein the DN200 nodular cast iron pipe and the DN400 nodular cast iron pipe are constructed in a segmented mode, the DN200 and DN400 pipelines are smoothly connected for 5 times by scientifically utilizing the limit value of the deflection angle of the nodular cast iron pipes and utilizing a 45-degree elbow or a 90-degree elbow, and the qualified water supply project is detected through a hydrostatic test.
Example 1
In the method for the segmental construction of the long-distance nodular cast iron pipeline, the DN200 nodular cast iron pipeline is connected at a 90-degree elbow.
As shown in fig. 8, a 90 ° elbow (not shown in the figure) is installed at a connection point C at the elbow of the DN200 nodular cast iron pipe, and two working surfaces (a first working surface for pipeline installation and a second working surface for pipeline installation) are simultaneously developed before and after the 90 ° elbow. The second face clearance BC is about 10m and the first face end distance a is about 10.5m from the docking point C length AC.
The docking method of the embodiment comprises the following steps:
step 1, completing connection of a BC section of nodular cast iron pipeline and a 90-degree elbow, and measuring the distance of a CE section to BE 4.3m, wherein the BE section of nodular cast iron pipeline is a whole nodular cast iron pipe (5.7 m/pipe);
and 2, connecting a ball-milling cast iron pipe (5.7 m/root) from the point A to the point C to the point D, and adjusting the axis to ensure that the AC is vertical to the BC.
And 3, measuring the distance between the pipe orifice at the D point and the outer edge of the 90-degree elbow pipe orifice at the C point to be 4.36m by using a measuring tape, and then, cutting the length of the connecting CD pipeline to be 4.36+0.11 multiplied by 2 to be 4.58 m.
And 4, step 4: the CE pipe is deflected by 3 ° along the right side of the pipe, and the horizontal distance D is 4.3 × 1000 × sin3 ° -225 mm >110mm, so that CD sections of pipe can be inserted into the D-point orifice first.
And 5: the method comprises the steps of marking the insertion depth of a 90-degree elbow pipe fitting by using a red oil pen, deflecting a CD section pipeline (within a range of an allowed deflection angle of 3 degrees), deflecting a 90-degree elbow, mounting a CD and a 90-degree elbow section on a manual hoist, enabling a 90-degree elbow pipe orifice to be opposite to a CD section pipe orifice, and finally connecting two pipe sections CE and CD at a C point by using the manual hoist until the elbow mark is completely inserted into the CD pipe.
And 5: and after the pipeline connection is completed, carrying out a pressure test on the whole pipeline to detect the leakage condition of the pipeline. The connection point does not need to be detected separately, and only needs to be contained in the whole hydraulic test pipe section. The length of the pipe section of the pipeline hydrostatic test is not more than 1.0km, and the operation is as follows according to the water supply and drainage pipeline engineering construction and acceptance standard (GB 50268-2008) 9.2 pressure pipeline hydrostatic test:
(1) the maximum working pressure of the DN200 nodular cast iron pipe is 1.6MPa, and the test pressure of the pipeline hydrostatic test is 2.1MPa (usually 1.5 times);
(2) after the test pipe section is filled with water, the test pipe section is soaked fully under the condition of not more than working pressure and then subjected to hydrostatic test, wherein the soaking time is not less than 24 hours;
(3) a pre-test stage: slowly raising the water pressure in the pipeline to the test pressure and stabilizing the pressure for 30min, and if the pressure is reduced, injecting water to supplement the pressure, but not being higher than the test pressure; checking whether water leakage and damage occur at the pipeline interface, fittings and the like; when water leakage and damage occur, the pressure test is stopped in time, the reason is found out, and the pressure test is carried out again after corresponding measures are taken;
(4) a main test stage: stopping water injection and pressure compensation, and stabilizing for 15 min; when the pressure is reduced to be not more than 0.03MPa after 15min, reducing the test pressure to the working pressure and keeping the constant pressure for 30min, and if no water leakage phenomenon exists during appearance inspection, the hydrostatic test is qualified;
(5) when the pressure of the pipeline is increased, gas in the pipeline is removed; in the boosting process, when the pointer of the spring pressure gauge swings and is unstable and the boosting is slow, the pressure should be boosted after the air is exhausted again;
(6) before pressurization, checking whether the pipeline leaks water or seeps water, checking the back, the buttresses and the like, then boosting in three stages, wherein the three stages are respectively 0.8MPa, 1.6MPa and 2.1MPa, the back, the buttresses, the pipe body and the interfaces are checked in one liter, and boosting is continued when no abnormal phenomenon occurs;
(7) in the process of the hydrostatic test, people are strictly prohibited from standing at the back top support and the two ends of the pipeline;
(8) strictly prohibiting defect repair during the hydrostatic test; when defects exist, marks are made, and pressure is relieved for repair.
After detection, the whole section of the jointed pipeline is qualified after being subjected to pressure test detection, and the jointed mode is proved to be feasible because the pressed pipeline comprises a jointed point C.
Example 2
The embodiment provides a method for overlap-connecting long-distance nodular cast iron pipelines in segmental construction, and the embodiment is that DN400 nodular cast iron pipelines are connected at an elbow of 45 degrees.
As shown in fig. 9, a 45-degree elbow (not shown in the figure) is installed at a connection point C of the DN400 nodular cast iron pipe at the elbow, and one working surface is respectively developed before and after the 45-degree elbow, wherein about 10m is reserved in the AC section to start a first working surface, about 10.5m is reserved in the CB section to start a second working surface, and the connection of two pipelines is performed after the originally planned pipeline section is completed.
The docking method of the embodiment comprises the following steps:
step 1, completing connection of a BC section pipeline and a 45-degree elbow, and measuring the distance of a CE section to BE 4.8m, wherein the BE section nodular cast iron pipeline is a whole nodular cast iron pipe (5.7 m/pipe);
and 2, connecting a nodular cast iron pipe (5.7 m/root) from the point A to the point C to the point D, and adjusting the axis to keep the included angle between AC and BC at 135 degrees.
And 3, measuring the distance between the pipe orifice at the D point and the outer edge of the 45-degree elbow pipe orifice at the C point to be 4.08m by using a measuring tape, and then, cutting the length of the pipeline connected with the CD to be 4.08+0.11 multiplied by 2 to be 4.30 m.
And 4, step 4: the CE pipe is deflected 3 ° along the right side of the pipe, and the horizontal distance D is 4.8 × 1000 × sin3 ° × cos45 ° -177 mm >110mm, so CD sections of pipe can be inserted into the D-point orifice first.
And 5: inserting depth marks are made on 45-degree elbow pipe fittings by using a red oil pen, then the CD section pipeline is deflected (within the range of the allowed deflection angle of 3 degrees), meanwhile, the 45-degree elbow is also deflected, firstly, a CD and a 45-degree elbow section are installed on a manual hoist, so that the pipe orifice of the 45-degree elbow is opposite to the pipe orifice of the CD section, and finally, the two pipe sections CE and CD at the C point are connected by using the manual hoist until the elbow marks are completely inserted into the CD pipe.
Step 6: and after the pipeline connection is completed, carrying out a pressure test on the whole pipeline to detect the leakage condition of the pipeline. The connection point does not need to be detected separately, and only needs to be contained in the whole hydraulic test pipe section. The specific detection steps can refer to embodiment 1, and are not described herein any more, wherein the maximum working pressure of the DN400 ductile iron pipe is 1.0MPa, and the test pressure of the pipeline hydrostatic test is 1.5MPa (usually 1.5 times).
After detection, the whole section of the jointed pipeline is qualified after being subjected to pressure test detection, and the jointed mode is proved to be feasible because the pressed pipeline comprises a jointed point C.
In summary, the following steps: in the long-distance nodular cast iron pipeline subsection construction process, the DN200 and DN400 pipelines are smoothly connected by scientifically utilizing the limit value of the deflection angle of the nodular cast iron pipeline and utilizing a 45-degree elbow or a 90-degree elbow, and the whole connected pipeline is qualified through the hydrostatic test. The elbow pipe fitting is adopted to overlap the segmented pipeline, so that the pipeline overlap at the elbow can be realized, and more operation surfaces are provided for pipeline segmented construction. And moreover, because the elbow pipe fitting is adopted for connection, the working surfaces on two sides of the elbow can be simultaneously developed, the construction progress is accelerated, and the smooth and quick completion of the construction process is ensured.
The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made to the present invention by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (11)
1. A connection method for long-distance nodular cast iron pipeline subsection construction is characterized by comprising the following steps:
step S1, an elbow is installed, and two end parts of the elbow are respectively C1Point and C2A first operation surface and a second operation surface are simultaneously developed on two sides of the elbow, the nodular cast iron pipeline in the first operation surface is installed to the point A, and the nodular cast iron pipeline in the second operation surface is installed to the point B and both face the elbow for a certain distance;
step S2, starting construction from point B in the second working plane to the elbow, installing BC2Segment of nodular cast iron pipe, make BC2The section nodular cast iron pipeline is connected with the elbow;
step S3, calculating and cutting the AC needing connection in the first working face1The length of the nodular cast iron pipeline;
step S4, deflecting BC connected to the elbow in the second working plane2Segmenting the ductile iron pipeline and mixing AC1The nodular cast iron pipeline section is well connected with the nodular cast iron pipeline and the elbow in the first working surface, and the connection of the two pipeline sections at the elbow is completed.
2. The overlap-connection method for segmental construction of the long-distance ductile iron pipeline according to claim 1, wherein the elbow is a 45-degree elbow or a 90-degree elbow.
3. The method of claim 1, wherein the first operating plane AC is defined1The reserved length of the section is Lac, the insertion depth of the nodular cast iron pipeline is b, and then the AC is used1The length of the section nodular cast iron pipeline is Lac +2 b.
4. The connection method for the segmental construction of the long-distance nodular cast iron pipeline as claimed in claim 3, wherein the Lac is within the range of 8-12m, and the b is within the range of 105-115 mm.
5. The overlap-connection method for the segmental construction of the long-distance nodular cast iron pipeline as claimed in claim 1, wherein when the pipe diameter of the nodular cast iron pipe is 200-400mm, the length of the nodular cast iron pipe is L0, the maximum deflection angle of the nodular cast iron pipe is 3 degrees, and the reserved distance L in the second working plane is not less than 2.1+ L0 m.
6. The overlap-connection method for the segmental construction of the long-distance nodular cast iron pipeline as claimed in claim 1, wherein when the pipe diameter of the nodular cast iron pipe is 700-800mm, the length of the nodular cast iron pipe is L0, the maximum deflection angle of the nodular cast iron pipe is 2 degrees, and the reserved distance L in the second working plane is not less than 3.15+ L0 m.
7. The overlap-connection method for the segmental construction of the long-distance ductile cast iron pipeline according to any one of claims 1 to 6, wherein the specific operation of the step S4 is to mark the depth of the outer surface of the elbow and then deflect AC1Segment of nodular cast iron pipeline, and deflecting elbow to make its mouth and AC1The pipe openings of the sections are opposite, the nodular cast iron pipeline in the first working face is well connected with the elbow until the depth mark is completely inserted into the AC1Inside the pipe section.
8. A method for the sectional construction of the long-distance nodular cast iron pipeline according to any one of claims 1 to 6, wherein the nodular cast iron pipeline is installed by using a rubber ring, and the method is characterized in that the rubber ring and the pipe orifice on the nodular cast iron pipeline are cleaned, the rubber ring is arranged in a socket groove of the nodular cast iron pipeline, and the rubber ring is tapped to fit the pipe orifice.
9. A method of overlap joint in segmental construction of long-distance ductile iron pipes according to claim 8, wherein the outer surface of the spigot of the ductile iron pipe is ground to remove the melting point left after the machining.
10. A method of overlap joint in segmental construction of long-distance ductile iron pipelines according to claim 1, wherein the pipe orifice of the ductile iron pipeline is lubricated by a lubricant to facilitate the pipeline connection operation.
11. The overlap joint method for the segmental construction of the long-distance nodular cast iron pipeline according to claim 5, wherein the length L0 of the nodular cast iron pipeline is 5.7 mm.
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| CN113202974A (en) | 2021-08-03 |
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