CN104633392A - Joint coating method - Google Patents
Joint coating method Download PDFInfo
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- CN104633392A CN104633392A CN201410780656.XA CN201410780656A CN104633392A CN 104633392 A CN104633392 A CN 104633392A CN 201410780656 A CN201410780656 A CN 201410780656A CN 104633392 A CN104633392 A CN 104633392A
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- stirrup
- repaired mouth
- jointing
- steel
- inner lining
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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
- F16L58/00—Protection of pipes or pipe fittings against corrosion or incrustation
- F16L58/02—Protection of pipes or pipe fittings against corrosion or incrustation by means of internal or external coatings
- F16L58/04—Coatings characterised by the materials used
- F16L58/10—Coatings characterised by the materials used by rubber or plastics
- F16L58/1054—Coatings characterised by the materials used by rubber or plastics the coating being placed outside the pipe
Abstract
The invention discloses a joint coating method. The method comprises the steps that: firstly, surface treatment is carried out; secondly, preheating is carried out on a steel pipe; thirdly, the surface is coated with a joint coating piece; fourthly, the joint coating piece is coated with a metal interior lining panel; fifthly, coating and tightly locking are carried out on a steel hoop and an electric heating device; sixthly, warming is carried out by a program; seventhly, equipment is disassembled. The metal interior lining panel is high in rust-proof capacity, and is tightly connected with the joint coating piece as a whole in an adhesive mode, so that the barrier property to visible light, ultraviolet light, water, oxygen, and vapour of a joint coating layer is greatly improved, the mechanical damage resistance to a pointed object is enhanced, and the service life of the joint coating layer is greatly prolonged. By means of the steel hoop to carry out tightly locking and pressuring, enormous pressure is exerted on the joint coating piece during the softening and bonding process, the bonding strength on the steel pipe is greatly improved, the peeling strength under 23 DEG C can reach above 250 N / cm, the peeling strength under 50 DEG C can reach above 100 N / cm, and the peeling strength under 23 DEG C and the peeling strength under 50 DEG C are twice and five times stronger than the heat shrinking sleeve (belt) joint coating respectively.
Description
Technical field
The invention belongs to gas transmission, Pipeline Construction technical field, be specifically related to a kind of jointing method.
Background technique
The steel pipe that uses in pipe-line construction, must in advance through preservative treatment, 3LPE, 3LPP anticorrosive coat be pipeline outer anticorrosion in the anticorrosion structure that generally adopts.In pipeline corrosion protection process, often reserve soldering opening, general width is 100-150mm, and docking steel pipe is welded to each other at reserved weld bond place, and the prefabricated anticorrosive coat in two ends wraps on docking steel pipe.The anticorrosion of steel pipe soldering opening completes at the construction field (site), and the overall antiseptic effect of the joint coating on pipeline technology that it adopts on pipeline has great impact, because it is related to the final anticorrosive quality of whole piece pipeline.No matter in pre-fabricated factory, how excellent 3LPE, 3LPP anticorrosive coat quality is, if the bad steel pipe that will cause of on-the-spot repaired mouth effect produces heavy corrosion, the working life of buried pipeline shortened, even causes the serious consequences such as leakage.
The soldering opening of 3LPE, 3LPP anti-corrosion pipeline is anticorrosion generally adopts thermal shrinkable sleeve (band) patch technology, the method of construction of this technology is: process epoxy primer in rear brushing to repaired mouth ground, coated contraction cover (band) after priming paint surface drying, baking heat-contraction sleeve (band) makes it shrink, make the hotmelt melts on heat-contraction sleeve simultaneously, stop heating after reaching appropriate level, after heat-contraction sleeve cools naturally, be fixed on repaired mouth place.In use there is following shortcoming in this traditional thermal shrinkable sleeve patch technology:
1. thermal shrinkable sleeve (band) is general by artificial hand-held roasting handle flame baking, and temperature accuracy and uniformity are difficult to accurate control.Guarantee that temperature is on the low side not adhesive effect, local superheating easily makes thermal shrinkable sleeve (band) carbonize, and shrinks inconsistently to cause bubble and fold, repaired mouth difficult quality guarantee when heating uneven.
2. the hot melt adhesive polarity that thermal shrinkable sleeve (band) is used is strong, molecular weight is low, bad with PE or the PP compatibility on straight tube anticorrosive coat surface, in addition when crosslinked polyethylene base material is heated, elastic contractile force is little, limited to hot melt adhesive applied pressure, cannot be formed reliably bonding between hot melt adhesive with straight tube anticorrosive coat, after buried, unsticking cracking phenomena very easily occur, cause repaired mouth to lose efficacy.
3. radiant crosslinked polyethylene heat shrinkable band (cover) must obtain through multiple working procedures such as extruding and moulding, crosslinking with radiation, expanding, cooling, gluings, and cost is high, and cannot reclaim by thermoplastic, can cause certain destruction to environment.
Summary of the invention
For overcoming above-mentioned the deficiencies in the prior art, the object of the present invention is to provide the jointing method that a kind of technique is simple, easy to operate, antiseptic property is high.
The present invention is achieved by the following technical solutions:
A kind of jointing method, at least comprises the following steps:
A. surface treatment: scrubbing and derusting by sandblasting are carried out to the steel tube surface at joint coating on pipeline position;
B. steel pipe preheating: the steel pipe at joint coating on pipeline position is preheating to 30 ~ 100 DEG C;
C. repaired mouth sheet wraps: wrap repaired mouth sheet on the surface at joint coating on pipeline position;
D. coated metal interior lining panel: metal inner lining plate is wrapped on repaired mouth sheet;
E. wrap up and lock stirrup and electric heater: be wrapped in by stirrup outside metal inner lining plate, stirrup is locked by mechanical locking device end to end, electric heater covers stirrup skin, fits closely with stirrup;
F. temperature programmed control: switch on power, temperature controlling instrument setting value is adjusted to 180 ~ 260 DEG C, keeps 10 ~ 60min.; Cut off heating power supply, slowly cool to less than 50 DEG C;
G. remove facility: release mechanism locking device, remove electric heater and stirrup.
In step a of the present invention, after carrying out sand blast to repaired mouth position steel tube surface, steel tube surface quality should reach Sa2.5 level, is removed by steel tube surface dust clean immediately after derusting by sandblasting with pressurized air.
In step b of the present invention, multiple existing mode can be adopted, as electric heating coil heating, electromagnetic induction heating, infrared heating, the heating of liquid gas flame etc., the steel pipe at joint coating on pipeline position is preheating to 30 ~ 100 DEG C (with the infrared thermometry meter monitor temperature through verification, when external temperature is low, suitably can improve preheating temperature).The object of heating removes the moisture content be adsorbed on steel pipe, improves repaired mouth quality.
The present invention's repaired mouth sheet replaces existing thermal shrinkable sleeve (band), for 3LPE anticorrosive coat, the material of described repaired mouth sheet is maleic anhydride grafted polyethylene copolymer and poly blend, and its blending ratio is 1:0 ~ 1:10, and overall percent grafting reaches more than 0.1wt% and is advisable; For 3LPP anticorrosive coat, the material of described repaired mouth sheet is maleic anhydride inoculated polypropylene copolymer and polyacrylic blend, and its blending ratio is 1:0 ~ 1:10, and overall percent grafting reaches more than 0.1wt% and is advisable.
Have circular groove in the middle of repaired mouth sheet width direction (along pipeline axial direction), groove bosom is 1.0 ~ 3.0mm, and its width is advisable than the little 0 ~ 5mm of repaired mouth position annular weld bead width.Be close to steel pipe when groove can make repaired mouth sheet wrap, be also conducive to metal inner lining plate and be close to repaired mouth sheet material all the time, improve repaired mouth quality.
The minimum length that the length of repaired mouth sheet width direction straight portion is possible with the exposed steel pipe in weld bond place is consistent, and straight portion two ends are even thinning area, often holds width to be advisable at 50 ~ 100mm.The shortest 60mm less of pipeline girth of repaired mouth leaf length direction (along pipeline circumferential direction) straight portion, the longest 100mm more than pipeline girth, straight portion two ends are similarly even thinning area, often hold length to be advisable at 30 ~ 60mm.Even thinning area can make the prefabricated anticorrosive coat of repaired mouth sheet and two ends and self overlap smooth-going, is conducive to metal inner lining plate and is close to repaired mouth sheet material all the time, improves repaired mouth quality.
When the length change scope of the exposed steel pipe in repaired mouth position is excessive, can, according to the length customization repaired mouth sheet of the exposed steel pipe in welding bead both sides, make repaired mouth sheet groove both sides straight portion length corresponding with it.
The thickness of repaired mouth sheet straight portion should slightly larger than the prefabricated anticorrosive coat thickness in two ends, and reach the prefabricated anticorrosive coat thickness in two ends 100 ~ 150% are advisable.
With device tensions such as euphroes, then can fix with fixed plate or adhesive sticker, electric soldering iron also can be used to be welded and fixed when repaired mouth sheet wraps.
Length 20 ~ the 120mm longer than the prefabricated anticorrosive coat girth in two ends of metal inner lining plate, width 20 ~ 240mm wider than repaired mouth sheet, thickness is 0.2 ~ 1.0mm.Metal inner lining wrench tail two ends can panel beating shape in the arc-shaped in advance, and radius of arc is identical with steel pipe radius, and two ends radian is 30o ~ 60o separately.Metal inner lining sheet material matter is selected from one or more in stainless steel, galvanized steel, tin-coated steel, Aluminium Coated Steel, nickel-plated steel, chromium-plated steel, fine aluminium, aluminum alloy, fine copper or Cuprum alloy.
In steps d of the present invention, the metal inner lining plate wrapped can be temporary fixed with Pressure sensitive adhesive tape, by moving left and right the position of electric heating coil to tear adhesive sticker after upper electric heating coil to be wrapped.After construction completes, metal inner lining plate can bond together securely with repaired mouth sheet, becomes as a whole.Metal inner lining plate overlaps when wrapping up in into drum end to end, and in order to be integrated by lap also bonding one-tenth, the outer surface of metal inner lining plate is stained with adhesive film in advance, thickness 0.05 ~ 0.2mm.Film while flush with inner layer metal plate end, its excess-three limit 5 ~ 20mm narrower than overlap region, object is that adhesive overflows adhesion electric heating coil when preventing from being heated.
The material of adhesive film is the blend of maleic anhydride grafted polyethylene/polypropylene copolymer and ethylene/polypropylene, and its blending ratio is 1:0 ~ 1:10, and overall percent grafting reaches more than 0.1wt% and is advisable.
Stirrup material is carbon steel, alloy steel or stainless steel.Stirrup thickness 0.5 ~ 1.5mm, width is identical with electric heating coil, effective length ratio electric heating coil excircle length 10 ~ 50mm, is unlikely to overlap end to end occurs when field joint construction.
Stirrup is locked by mechanical locking device end to end, and mechanical locking device comprises screw thread locking mechanism, eccentric wheel locking mechanism, inclined-plane locking mechanism, four rod locking mechanisms etc., preferably uses screw thread locking mechanism.Use screw thread locking mechanism time, stirrup end to end respectively outer wraparound live a connecting rod, connecting rod freely can rotate around axle, facilitate hexagon socket head cap screw connection lock.Bolt quantity is 3 ~ 9, is evenly distributed on the width direction of stirrup.Total coupling mechanism force computer capacity as follows: coupling mechanism force=(0.25 ~ 2.0) × diameter of steel tube × stirrup width, locking unit of force in formula is kgf, and the unit of diameter of steel tube and stirrup width is cm.After determining coupling mechanism force, should according to selected bolt quantity, thread surface state, lubrication circumstances and relevant design specification determination hexagon socket head cap screw specification and screw-down torque.In construction, repaired mouth sheet may diminish by coupling mechanism force after thermal softening, for keeping coupling mechanism force as far as possible, can use spring washer or spring.
In step f of the present invention, available electric tool Quick fastening hexagon socket head cap screw, is finally fastened to prescribed torque with torque-indicating wrencg.For reducing friction on the impact of moment of torsion, reduce coupling mechanism force wave range, hexagon socket head cap screw should smear lubricating grease.Progressively tightening in the process of hexagon socket head cap screw, metal inner lining plate is also corresponding to be tightened up, and realizes fitting tightly between repaired mouth sheet and metal inner lining plate and between each layer of repaired mouth facility.
Electric heater covers stirrup skin, fits closely with stirrup.Described electric heater can be electric heating coil or electric heating piece, preferred electric heating piece.
The width of described electric heating piece is identical with stirrup width, and thickness is 3 ~ 20mm; Electric heating piece is one piece of entirety or is circumferentially divided into 2 ~ 10, adjacent two panels interval 2 ~ 10mm.In the process that stirrup is removed after coated metal interior lining panel and completion, can there is larger change in curvature, the electric heating piece being divided into multi-disc is not fragile.Electric heating piece is stainless steel mica heating collar, cast aluminium heating collar, cast copper heating collar or stainless ceramic heating collar.The total output of electric heating piece is determined as follows: total output=diameter of steel tube × (0.02 ~ 0.06), and in formula, diameter of steel tube unit is mm, and total output unit is kW.
In step f of the present invention, repaired mouth sheet may reduce by coupling mechanism force after thermal softening, can be again fastening with torque-indicating wrencg every 1 ~ 5 minute, and time fastening, moment of torsion should reach 30% ~ 90% of regulation initial torque.
Epoxy primer according to actual conditions, after the stepb, evenly can be coated in the whole surface of repaired mouth position steel pipe, then wrap repaired mouth sheet again on the surface of epoxy primer by the present invention.The coating of epoxy primer by the operating guidance of epoxy primer, by epoxy primer brush along the brushing of pipeline circumference or the spraying of use spraying equipment, can be avoided bubble, makes epoxy primer be coated in the whole surface of repaired mouth position steel pipe equably.If epoxy primer temperature is too low cause coating inconvenience, epoxy primer suitably can be heated.Consider the impact of sleet sand and dust in field construction, after coating epoxy primer, wrap repaired mouth sheet material immediately, epoxy primer so just can be avoided to be polluted in the process waiting for surface drying.
When not needing repaired mouth sheet bonding with metal inner lining plate, repaired mouth sheet should adopt double layer construction, namely applies layer of polyethylene/polypropylene in addition at the skin of above-mentioned repaired mouth sheet, and its thickness is 0.1 ~ 0.5mm.
Compared with prior art, tool has the following advantages in the present invention:
1, metal inner lining plate antirust ability is strong, and be integrated with repaired mouth sheet strong bond, greatly improve the barrier of repaired mouth layer to visible ray, ultraviolet, water, oxygen and water vapour, also strengthened to the resistivity of sharp objects mechanical deterioration, the repaired mouth layer life-span significantly promotes.
2. the present invention adopts stirrup to lock pressurization, can apply immense pressure, significantly improve the bonding strength to steel pipe to repaired mouth sheet in softening bonding process; The peeling strength of 23 DEG C can reach more than 250N/cm, and the peeling strength of 50 DEG C reaches 100 more than N/cm, is respectively more than 2 times and 5 times of heat-contraction sleeve (band) repaired mouth;
3. adopt construction technology of the present invention, repaired mouth structure and straight tube 2LPE, 2LPP anti-corrosion layer structure are similar, repaired mouth sheet maintenance thermoplasticity itself, and can fuse into completely integrally with the prefabricated anticorrosive coat surface layer in two ends and self lap-joint of repaired mouth sheet, sealing effect is fabulous;
4. repaired mouth facility of the present invention, stablize controlled temperature and pressure condition for the fusing of repaired mouth sheet and bonding provide, construction quality is good, and quality stability is high;
5. repaired mouth facility of the present invention are simple and reliable, with low cost, and operating expenses is low;
6. repaired mouth sheet of the present invention need not crosslinking with radiation, and with low cost, leftover pieces can be recycled, free from environmental pollution.
Accompanying drawing explanation
Fig. 1 is the in running order schematic diagram of jointing method of the present invention repaired mouth facility used;
Wherein, 1 electric heater 2 screw thread locking mechanism 3 stirrup 4 metal inner lining plate 5 repaired mouth sheet.
Embodiment
Further illustrate the present invention below by embodiment, following examples are the present invention's preferably mode of execution, but embodiments of the present invention are not by the restriction of following embodiment.
Embodiment 1:
A 3LPP pipeline of Ф 610, prefabricated anticorrosive coat thickness 3mm, repaired mouth sheet 5 width 400mm, thickness 3.3mm, jointing method comprises the following steps:
A. surface treatment: carry out scrubbing and derusting by sandblasting to the steel tube surface at joint coating on pipeline position, steel tube surface quality should reach Sa2.5 level, removes clean with pressurized air after derusting by sandblasting immediately by steel tube surface dust;
B. steel pipe preheating: the steel pipe at joint coating on pipeline position is preheating to 75 DEG C;
C. repaired mouth sheet 5 wraps: wrap repaired mouth sheet 5 at joint coating on pipeline position, the material of repaired mouth sheet 5 is the 4:1 blend of polypropylene and maleic anhydride inoculated polypropylene copolymer, circular groove is had in the middle of repaired mouth sheet 5 width direction (along pipeline axial direction), groove bosom is 1.5mm, its width 2mm less of weld bond place annular weld bead width; The length of repaired mouth sheet 5 width direction straight portion is consistent with weld bond place exposed steel pipe minimum length, and straight portion two ends are even thinning area, often holds width to be 80mm; The length of repaired mouth sheet 5 length direction (along pipeline circumferential direction) straight portion is greater than pipeline girth 50mm, and straight portion two ends are similarly even thinning area, often holds length to be 50mm;
D. coated metal interior lining panel 4: be wrapped in by metal inner lining plate 4 on repaired mouth sheet 5, the outer surface of metal inner lining plate 4 is stained with adhesive film in advance, thickness 0.1mm; Film while flush with metal inner lining plate end, its excess-three limit 10mm narrower than overlap region; The material of adhesive film is the 4:1 blend of polypropylene and maleic anhydride inoculated polypropylene copolymer;
E. wrap up and lock stirrup 3 and electric heater 1: be wrapped in by stirrup 3 outside metal inner lining plate 4, stirrup 3 is locked by screw thread locking mechanism 2 end to end, it is outer that electric heater 1 covers stirrup 3, fits closely with stirrup 3;
F. temperature programmed control: switch on power, temperature controlling instrument setting value is adjusted to 240 DEG C, keeps 25min.; Cut off heating power supply, slowly cool to less than 50 DEG C;
G. remove facility: unclamp hexagon socket head cap screw, remove stirrup 3 and electric heater 1.
Metal inner lining plate 4 of the present invention is wrapped in outside repaired mouth sheet 5 and becomes drum, partly overlaps end to end.The length of metal inner lining plate 4 is 2000mm, width 500mm, thickness 0.3mm, material selection 304-1/2H stainless steel cold-rolled plate.Metal inner lining wrench tail two ends are panel beating shape in the arc-shaped in advance, and radius of arc is 305mm, and two ends radian is all 35o.
Stirrup 3 is wrapped in outside metal inner lining plate 4, and material is 304-1/2H stainless steel cold-rolled plate.Stirrup 3 thickness 0.5mm, width 450mm, length is 1945mm.
Stirrup 3 is locked by screw thread locking mechanism 2 end to end, and bolt quantity is 5, is evenly distributed on the width direction of stirrup 1.Screw thread performance rate selects 6.8 grades, surface oxidation treatment, scribbles containing molybdenum lubricating grease, nominal diameter M8, and a spring washer joined by each bolt.Total coupling mechanism force is 3500kgf, and each hexagon socket head cap screw coupling mechanism force is 700kgf, and screw-down torque is 12Nm.
Electric heater 1 is electric heating piece, and it is outer that electric heating piece covers stirrup 3, fits closely with stirrup 3.Electric heating piece is made up of two pieces of semicircle electric heating pieces, interval 6mm between semicircle electric heating piece.The width 450mm of semicircle electric heating piece, thickness is 5mm.
Electric heating piece is stainless steel mica electric heating piece, and total output is 18kW, inner and outer surface flat smooth.Power supply is the common industrial-frequency alternating current of 220V or 380V.
Embodiment 2:
A 3LPE pipeline of Ф 1219, two ends prefabricated anticorrosive coat thickness 3.7mm, repaired mouth sheet 5 width 450mm, thickness 4.6mm, jointing method comprises the following steps:
A. surface treatment: carry out scrubbing and derusting by sandblasting to the steel tube surface at joint coating on pipeline position, makes steel tube surface quality reach Sa2.5 level, is removed by steel tube surface dust clean immediately after rust cleaning with pressurized air;
B. steel pipe preheating: the steel pipe at joint coating on pipeline position is preheating to 50 DEG C;
C. repaired mouth sheet 5 wraps: wrap repaired mouth sheet 5 on the surface at joint coating on pipeline position, and the material of repaired mouth sheet 5 is maleic anhydride grafted polyethylene copolymer, and percent grafting is 0.25wt%; Have circular groove in the middle of repaired mouth sheet 5 width direction (along pipeline axial direction), groove bosom is 2.0mm, its width 3mm less of weld bond place annular weld bead width; The length of repaired mouth sheet 5 width direction straight portion is consistent with weld bond place exposed steel pipe minimum length, and straight portion two ends are even thinning area, often holds width to be 60mm; The length of repaired mouth sheet 5 length direction (along pipeline circumferential direction) straight portion is less than pipeline girth 30mm, and straight portion two ends are similarly even thinning area, often holds length to be 60mm;
D. coated metal interior lining panel 4: be wrapped in by metal inner lining plate 4 on repaired mouth sheet 5, the outer surface of metal inner lining plate 4 is stained with adhesive film in advance, thickness 0.05mm; Film while flush with metal inner lining plate end, its excess-three limit 5mm narrower than overlap region; The material of adhesive film is maleic anhydride grafted polyethylene copolymer;
E. wrap up and lock stirrup 3 and electric heater 1: be wrapped in by stirrup 3 outside metal inner lining plate 4, stirrup 3 is locked by screw thread locking mechanism 2 end to end, it is outer that electric heater 1 covers stirrup 3, fits closely with stirrup 3;
F. temperature programmed control: switch on power, temperature controlling instrument setting value is adjusted to 200 DEG C, keeps 50min.; Can be again fastening with torque-indicating wrencg every 1 ~ 5 minute, time fastening, moment of torsion should reach 30% ~ 90% of regulation initial torque.Cut off heating power supply, slowly cool to less than 50 DEG C;
G. remove facility: unclamp hexagon socket head cap screw, remove stirrup 3 and electric heater 1.
Metal inner lining plate 4 of the present invention is wrapped in outside repaired mouth sheet 5 and becomes drum, partly overlaps end to end.Metal inner lining plate 4 length is 3950mm, width 690mm, thickness 0.5mm.Metal inner lining plate 4 is two ends panel beating shape in the arc-shaped in advance end to end, and radius of arc is 610mm, and two ends radian is all 45o.Metal inner lining plate 4 material selection 3 type aluminum alloy.
Stirrup 3 is wrapped in outside metal inner lining plate 4 and becomes cylindric.Material is 316-3/4H stainless steel cold-rolled plate.Stirrup 3 thickness 0.8mm, length is 3868mm.
Stirrup 3 is locked by hexagon socket head cap screw 2 end to end, and bolt quantity is 7, is evenly distributed on the width direction of stirrup 3.Screw thread performance rate selects 8.8 grades, surface oxidation treatment, scribbles containing molybdenum lubricating grease, nominal diameter M10, and a spring washer joined by each bolt.Total coupling mechanism force is 7000kgf, and each hexagon socket head cap screw coupling mechanism force is 1000kgf, and screw-down torque is 22Nm.
Electric heater 1 is electric heating piece, and it is outer that electric heating piece covers stirrup 3, fits closely with stirrup 3.Electric heating piece is made up of two pieces of semicircle electric heating pieces, interval 8mm between semicircle electric heating piece.The width 590mm of semicircle electric heating piece, thickness is 6mm.
Electric heating piece is stainless steel mica electric heating piece, and total output is 40kW, inner and outer surface flat smooth.Power supply is the common industrial-frequency alternating current of 220V or 380V.
Comparative example 1:
A kind of method for joint coating on pipeline comprises the following steps successively:
A. surface treatment: carry out scrubbing, derusting by sandblasting to the steel tube surface at joint coating on pipeline position, makes steel tube surface quality reach Sa2.5 level, is removed by steel tube surface dust clean immediately after rust cleaning with pressurized air;
B. surperficial preheating: the steel tube surface at joint coating on pipeline position is preheating to 50 ~ 75 DEG C with electromagnetic induction electrothermal method, with the infrared thermometry meter monitor temperature through verification, suitably can improve preheating temperature when external temperature is low;
C. priming is coated with: whole surface epoxy primer being evenly coated in repaired mouth position steel pipe;
D. thermal shrinkable sleeve repaired mouth: thermal shrinkable sleeve is coated to repaired mouth position, carries out electric heating with intermediate frequency electric heating apparatus to thermal shrinkable sleeve, and electric heating temperature is 140 ~ 160 DEG C, and make thermal shrinkable sleeve shrink pack be layed onto repaired mouth position, repaired mouth has operated, and effect assessment result is as shown in table 1.
Table 1 is the effect assessment result of each embodiment and comparative example joint coating on pipeline
Claims (23)
1. a jointing method, is characterized in that, at least comprises the steps:
A. surface treatment: scrubbing and derusting by sandblasting are carried out to the steel tube surface at joint coating on pipeline position;
B. steel pipe preheating: the steel pipe at joint coating on pipeline position is preheating to 30 ~ 100 DEG C;
C. repaired mouth sheet wraps: wrap repaired mouth sheet on the surface at joint coating on pipeline position;
D. coated metal interior lining panel: metal inner lining plate is wrapped on repaired mouth sheet;
E. wrap up and lock stirrup and electric heater: be wrapped in by stirrup outside metal inner lining plate, stirrup is locked by mechanical locking device end to end, electric heater covers stirrup skin, fits closely with stirrup;
F. temperature programmed control: switch on power, temperature controlling instrument setting value is adjusted to 180 ~ 260 DEG C, keeps 10 ~ 60min.; Cut off heating power supply, slowly cool to less than 50 DEG C;
G. remove facility: release mechanism locking device, remove electric heater and stirrup.
2. jointing method according to claim 1, is characterized in that: in step b, and the mode of preheating is electric heating coil heating, electromagnetic induction heating, infrared heating or the heating of liquid gas flame.
3. jointing method according to claim 1, it is characterized in that: for 3LPE anticorrosive coat, the material of described repaired mouth sheet is maleic anhydride grafted polyethylene copolymer and poly blend, and its blending ratio is 1:0 ~ 1:10, and overall percent grafting reaches more than 0.1wt%; For 3LPP anticorrosive coat, the material of described repaired mouth sheet is maleic anhydride inoculated polypropylene copolymer and polyacrylic blend, and its blending ratio is 1:0 ~ 1:10, and overall percent grafting reaches more than 0.1wt%.
4. jointing method according to claim 1, is characterized in that: have circular groove in the middle of repaired mouth sheet width direction, groove bosom is 1.0 ~ 3.0mm, its width 0 ~ 5mm less of repaired mouth position annular weld bead width.
5. jointing method according to claim 4, is characterized in that: the minimum length of the steel pipe that the length of repaired mouth sheet width direction straight portion is exposed with repaired mouth position is consistent, and straight portion two ends are even thinning area, often holds width at 50 ~ 100mm; The shortest 60mm less of pipeline girth of repaired mouth leaf length direction straight portion, the longest 100mm more than pipeline girth, straight portion two ends are similarly even thinning area, often hold length at 30 ~ 60mm.
6. jointing method according to claim 4, is characterized in that: the thickness of repaired mouth sheet straight portion is 100 ~ 150% of the prefabricated anticorrosive coat thickness in two ends.
7. jointing method according to claim 1, is characterized in that: the length 20 ~ 120mm longer than the prefabricated anticorrosive coat girth in two ends of metal inner lining plate, width 20 ~ 240mm wider than repaired mouth sheet, thickness is 0.2 ~ 1.0mm.
8. jointing method according to claim 1, is characterized in that: metal inner lining wrench tail two ends can panel beating shape in the arc-shaped in advance, and radius of arc is identical with steel pipe radius, and two ends radian is 30o ~ 60o separately.
9. jointing method according to claim 1, is characterized in that: metal inner lining sheet material matter is selected from one or more in stainless steel, galvanized steel, tin-coated steel, Aluminium Coated Steel, nickel-plated steel, chromium-plated steel, fine aluminium, aluminum alloy, fine copper or Cuprum alloy.
10. jointing method according to claim 1, is characterized in that: the outer surface of metal inner lining plate is stained with adhesive film in advance, thickness 0.05 ~ 0.2mm, flushing with metal inner lining plate end of film, its excess-three limit 5 ~ 20mm narrower than overlap region.
11. jointing methods according to claim 10, it is characterized in that: the material of adhesive film is the blend of maleic anhydride grafted polyethylene/polypropylene copolymer and ethylene/polypropylene, its blending ratio is 1:0 ~ 1:10, and overall percent grafting reaches more than 0.1wt%.
12. jointing methods according to claim 1, is characterized in that: stirrup thickness 0.5 ~ 1.5mm, width 20 ~ 100mm narrower than metal inner lining plate; Length is than two ends prefabricated anticorrosive coat week length 5 ~ 50mm.
13. jointing methods according to claim 12, is characterized in that: stirrup material is carbon steel, alloy steel or stainless steel.
14. jointing methods according to claim 1, is characterized in that: mechanical locking device is screw thread locking mechanism, eccentric wheel locking mechanism, inclined-plane locking mechanism or four rod locking mechanisms, are preferably screw thread locking mechanism.
15. jointing methods according to claim 14, it is characterized in that: when adopting screw thread locking mechanism locking stirrup, stirrup end to end respectively outer wraparound live a connecting rod, connecting rod freely can rotate around axle, hexagon socket head cap screw is facilitated to connect locking, bolt quantity is 3 ~ 9, is evenly distributed on the width direction of stirrup.
16. jointing methods according to claim 15, is characterized in that: can use spring washer or spring when hexagon socket head cap screw connects.
17. jointing methods according to any one of claim 1-16, it is characterized in that: extend long 50 ~ 100mm in stirrup inwall welding one of end to end, width is identical with stirrup, the compressing tablet of thick 0.5 ~ 1.0mm, stretches into during installation between opposite stirrup and metal inner lining plate.
18. jointing methods according to claim 1, is characterized in that: described electric heater is electric heating coil or electric heating piece, preferred electric heating piece.
19. jointing methods according to claim 18, is characterized in that: the width of described electric heating piece is identical with stirrup width, and thickness is 3 ~ 20mm; Electric heating piece is one piece of entirety or is circumferentially divided into 2 ~ 10, adjacent two panels interval 2 ~ 10mm.
20. jointing methods according to claim 18, is characterized in that: electric heating piece is stainless steel mica heater band, cast aluminium heater band, cast copper heater band or stainless ceramic heater band.
21. jointing methods according to claim 1, is characterized in that: after the stepb, epoxy primer are evenly coated in the whole surface of repaired mouth position steel pipe, then wrap repaired mouth sheet on the surface of epoxy primer.
22. jointing methods according to claim 1, is characterized in that: in step f, and every 1 ~ 5 minute with torque-indicating wrencg again fastening stirrup, time fastening, moment of torsion should reach 30% ~ 90% of regulation initial torque.
23. jointing methods according to claim 1, it is characterized in that: when not needing repaired mouth sheet bonding with metal inner lining plate, repaired mouth sheet adopts double layer construction, and namely apply layer of polyethylene/polypropylene in addition at the skin of repaired mouth sheet, its thickness is 0.1 ~ 0.5mm.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410780656.XA CN104633392B (en) | 2014-12-17 | 2014-12-17 | A kind of jointing method |
Applications Claiming Priority (1)
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| WO2016095766A1 (en) * | 2014-12-17 | 2016-06-23 | 四川金发科技发展有限公司 | Pipeline-joint coating machine, construction method and novel pipeline-joint coating structure |
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| CN104633392B (en) | 2017-09-29 |
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