CN111992474B - Full-coating method of anticorrosive paint for inner wall of small-drift-diameter straight pipe or special-shaped metal pipeline - Google Patents
Full-coating method of anticorrosive paint for inner wall of small-drift-diameter straight pipe or special-shaped metal pipeline Download PDFInfo
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D7/00—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials
- B05D7/22—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials to internal surfaces, e.g. of tubes
- B05D7/222—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials to internal surfaces, e.g. of tubes of pipes
- B05D7/225—Coating inside the pipe
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- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D3/00—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials
- B05D3/04—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials by exposure to gases
- B05D3/0486—Operating the coating or treatment in a controlled atmosphere
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D3/00—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials
- B05D3/12—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials by mechanical means
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- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
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- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D2350/00—Pretreatment of the substrate
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Abstract
The invention discloses a method for fully coating anticorrosive paint on the inner wall of a small-drift-diameter straight pipe or a special-shaped metal pipeline, which is characterized by comprising the following steps of: s1, processing the inner surface of a pipeline; s2, coating and detecting pipelines: s2.1, preparing the anticorrosive paint on site; s2.2, judging whether the requirements of the coating process are met; s2.3, judging whether the coating environment condition is met; s2.4, coating the inner wall of the pipe fitting; and S3, checking and accepting. The invention solves the problems of limited construction space and coating quality of small-drift-diameter straight pipes and various special-shaped pipe fittings, effectively ensures the coating quality of the anticorrosive coating, and is beneficial to realizing corrosion protection of metal pipelines.
Description
Technical Field
The invention belongs to the field of pipeline corrosion prevention, and particularly relates to a full coating method of a small-drift-diameter straight pipe or special-shaped metal pipeline inner wall anticorrosive coating.
Background
In recent years, with the continuous application of pipelines made of different metal materials such as red copper, copper-nickel alloy, duplex stainless steel, titanium alloy and the like on ship seawater pipelines, the corrosion problems of ship seawater pipelines such as galvanic corrosion, crevice corrosion, weld corrosion and the like are more prominent, and the use safety of ship equipment is seriously influenced.
Relevant researches show that the corrosion problem of the metal pipeline can be effectively solved by coating anticorrosive coatings on the inner wall, the outer wall, the flange sealing surface and the surface of the flange plate of the metal pipeline and adopting an insulating fastener. When the inner wall of the metal pipeline is completely coated with the anticorrosive paint, the anticorrosive paint coating on the inner wall of the pipeline is required not only to have no leakage point, but also to reach the specified thickness.
However, when the inner walls of straight pipes (hereinafter, collectively referred to as "small-diameter straight pipes") or all special-shaped metal pipelines (hereinafter, collectively referred to as "special-shaped metal pipes") with pipe diameters smaller than 32mm, such as Z-shaped, S-shaped, continuous 90-degree bends, are completely coated with the anticorrosive paint, the construction difficulty is high due to space limitation, and the coating quality of the anticorrosive paint is difficult to ensure.
Disclosure of Invention
Aiming at least one of the defects or improvement requirements in the prior art, the invention provides a full coating method of an anticorrosive coating on the inner wall of a small-drift-diameter straight pipe or a special-shaped metal pipeline aiming at the small-drift-diameter straight pipe and various special-shaped metal pipes, which can effectively ensure the coating quality of the anticorrosive coating and is beneficial to realizing corrosion protection of the metal pipeline.
In order to achieve the above object, according to one aspect of the present invention, there is provided a method for fully coating an anticorrosive coating on an inner wall of a small-bore straight pipe or a special-shaped metal pipeline, comprising the steps of:
s1, processing the inner surface of a pipeline:
for a straight pipe or a special-shaped metal pipe with the pipe fitting drift diameter smaller than 32mm, after receiving the pipe, firstly using an electronic endoscope to carry out internal inspection on the pipeline, and then adopting a liquid sand blasting method to carry out inner surface treatment on the pipeline;
cleaning the interior of the pipeline immediately after liquid sand blasting, and then drying the pipeline;
after the treatment and acceptance of the inner surface of the pipeline are qualified, removing surface dust, and waiting for entering a coating link;
s2, coating and detecting the pipeline, which comprises the following substeps:
s2.1, preparing the anticorrosive paint on site;
s2.2, judging whether the requirements of the coating process are met;
s2.3, judging whether the coating environment condition is met;
s2.4, implementing a coating process on the inner wall of the pipe fitting according to the following steps:
the inner wall of the pipeline is sprayed, and then the inner wall is subjected to rolling brushing by using a flexible shaft inner rolling brush after the spraying, so that the adhesion of enamel is improved, and sagging is cleaned in time; performing internal inspection on the pipeline by using an electronic endoscope in the interval period of each paint, performing coating repair on macroscopic leakage points and polishing the sagging, and then performing next painting; the total thickness of the paint film after coating is more than 300 mu m;
s3, checking and accepting:
for all the coated pipelines, detecting a paint film on the inner wall of the pipeline by using an electric spark detector, searching a leakage point or a part with the thickness of the paint film being less than 300 mu m, and re-coating until the paint film reaches the standard;
performing spot check on the thickness of a paint film on the inner wall of the same batch of pre-delivered pipe fittings, wherein the qualification rate of the spot check reaches 100%;
detecting the paint film covering quality of the inner wall of the pipeline by using an electric spark detector for the inner wall of the same batch of pre-delivered pipe fittings, wherein the electric spark detector is required to be incapable of generating sparks, and the qualification rate of spot inspection reaches 100%;
when the two items are both satisfied, the acceptance is qualified.
Preferably, when the thickness and the leakage point of the paint film on the inner wall of the pipeline are detected by adopting an electric spark detector, 1500V detection voltage is set according to the instruction of the instrument, and the leakage point or the part of the paint film with the thickness lower than 300 mu m is searched. The probe is preferably a conductive metal spherical braid. The probes penetrate into the pipeline from two ends of the special-shaped metal pipeline to detect the anticorrosive paint coating, and the probes are flexibly connected with the high-pressure gun when necessary so as to ensure that the probes can detect all parts in the special-shaped metal pipeline.
Preferably, in step S1, the conditions for acceptable acceptance of the treatment of the inner surface of the pipeline are as follows: through electronic endoscopy, the surface reaches the rust removal grade standard of Sa2.5, and the roughness value is more than 5 mu m;
when the surface has visible grease, the grease is removed by using a surfactant or a cleaning agent (preferably, a non-film-forming type), and the grease is completely dried after the treatment.
Preferably, in step S2.1,
the preparation of the on-site anticorrosive paint is strictly operated according to the product use instruction, and the prepared anticorrosive paint is used after being filtered by a clean copper filter screen.
Preferably, in step S2.1,
standing the prepared anticorrosive paint for a preset time, and using the prepared anticorrosive paint after the temperature is reduced to a preset temperature and the anticorrosive paint is pulled into a line; the prepared anticorrosive paint is used within 2h, and when the prepared anticorrosive paint is dry and thick, the prepared anticorrosive paint can be added with a diluent and then used continuously.
Preferably, in step S2.2, the requirements for the coating process are:
(1) The pipeline after finishing surface treatment must brush 1 st anticorrosive paint the same day, prevent the metal surface from oxidizing again;
(2) When the 1 st coating cannot be carried out on the same day, secondary sand blasting or polishing is required before the 1 st anticorrosive coating is coated subsequently.
Preferably, in step S2.3, the coating environmental conditions are:
(1) When the relative humidity exceeds 85 percent, the paint can not be coated;
(2) In order to ensure the drying of the coating surface, the coating adopts dew point management; before coating, measuring the dew point of air and the temperature of the coated surface, and when the temperature of the coated surface is higher than the dew point by more than 3 ℃, confirming that the surface is dry and can be coated; when the temperature of the coated surface is higher than the dew point and is lower than 3 ℃ or the air temperature is lower than 10 ℃, the coating is not required;
(3) The coating is carried out at an air temperature of 15 ℃ to 40 ℃.
Preferably, in step S2.4, after each brush coating or spray coating, the anticorrosive paint is ensured to be complete, flat, free from sagging and free from accumulation by manual coating.
Preferably, in step S2.4, after the previous paint is completely dried, the next anticorrosive paint is applied, and the interval time of each paint is not less than 24 hours.
Preferably, after the step S2.4, the coated pipe orifice of the pipe fitting is temporarily coated by using a wrapping and anti-collision material, so that the completeness of the paint surface before handing over, a transportation process and installation of a real ship is guaranteed.
Preferably, the metal pipe is made of any one of red copper, copper alloy, common steel, stainless steel and titanium alloy.
In order to achieve the above object, according to one aspect of the present invention, there is provided a method for fully coating an anticorrosive coating on an inner wall of a small-bore straight pipe or a special-shaped metal pipeline used in the inspection and acceptance step S3, comprising the steps of:
a method for detecting the thickness and leakage points of an anticorrosive paint in a small-drift-diameter straight pipe or a special-shaped metal pipe is characterized by comprising the following steps: the method for detecting the thickness and the leakage point of the anticorrosive paint inside the straight pipe or the special-shaped metal pipeline with the drift diameter smaller than 32mm by using the electric spark detector comprises the following steps:
s3.1, before detection, connecting a metal plug bayonet on a high-pressure gun connecting line of the electric spark detector with a host high-pressure output socket bayonet;
s3.2, a first wiring scheme: placing a connecting magnet at the position without a coating at the tail end of the pipeline, connecting one end of a short grounding wire to the connecting magnet, grounding the other end of the short grounding wire, connecting one end of a long grounding wire to the connecting magnet, and connecting the other end of the long grounding wire to a binding post of a host machine;
alternatively, the first and second electrodes may be,
and a second wiring scheme: placing a connecting magnet at the part without a coating at the tail end of the pipeline, connecting one end of a short grounding wire to the connecting magnet, grounding the other end of the short grounding wire, connecting one end of a long grounding wire to a binding post of a host machine, and connecting the other end of the long grounding wire to a grounding rod for dragging detection on the ground;
s3.3, mounting the probe at the top end of the high-pressure gun;
s3.4, selecting a test voltage according to the thickness of the anti-corrosion coating to be required, and adjusting the output voltage of the electric spark detector to the test voltage;
the test voltage was selected as follows:
1) When the average thickness of the anticorrosive coating is more than 0.5mm,
U＝7900T 1/2
2) When the average thickness of the anticorrosive coating is less than or equal to 0.5mm,
U＝3300T 1/2 or U = T × 5V/μm
Where U-test voltage, unit: v;
t-average thickness of anticorrosive coating, unit: mm;
s3.5, trying to enable the probe to approach or touch the electric conductor of the detected object, if the discharge spark can be seen and the acousto-optic alarm is given, and if the acousto-optic alarm disappears correspondingly when the probe leaves the detected object, indicating that the instrument works normally, and starting detection;
s3.6, respectively enabling the probes to penetrate into the pipeline from the two ends of the metal pipe to detect the anticorrosive coating, and detecting whether an acousto-optic alarm is given or not;
s3.7, judging that the anti-corrosion coating in the pipeline has no leakage point and the coating thickness meets the corrosion protection requirement if all parts in the pipeline are not subjected to sound and light alarm after detection.
Preferably, if the ground on which the test is located is dry, the ground rod of the long ground line is inserted into the ground instead when carrying out step S3.2 wiring scheme two, in order to reduce the ground resistance.
Preferably, in step S3.3, the probe is a conductive metal ball braid probe.
Preferably, in step S3.3, a soft connection is used between the probe and the high pressure gun to ensure that the probe can detect all parts inside the pipeline.
Preferably, in step S3.4, the method for adjusting the output voltage of the electric spark detector is as follows:
the tester turns on the power switch, wears the high-voltage glove, presses the high-voltage output button, the microcomputer in the electric spark detector automatically changes, the power supply voltage indicator lights go out, the output high-voltage indicator lights up, the liquid crystal gauge outfit displays and converts the output high-voltage value, and the output knob is adjusted to make the display value be the required test voltage; and (4) loosening the high-voltage output button, and enabling the electric spark detector to be in a standby working state.
Preferably, after the electric spark detector finishes each detection, the output adjusting knob is adjusted to be minimum; step S3.4 is repeated the next time re-inspection is used.
Preferably, step S3.7 is further included after step S3.6, that is, after the detection is finished, the switches of the electric spark detector are restored to the original state; after the power supply is turned off, the probe and the grounding wire of the host are directly short-circuited and discharged and then are stored.
Preferably, the metal pipe is made of any one of red copper, copper alloy, common steel, stainless steel and titanium alloy.
Preferably, the anti-corrosive coating comprises an epoxy enamel.
The above-described preferred features may be combined with each other as long as they do not conflict with each other.
Generally, compared with the prior art, the technical scheme conceived by the invention has the following beneficial effects:
the method for fully coating the anticorrosive paint on the inner wall of the small-drift-diameter straight pipe or the special-shaped metal pipeline solves the problems of limited construction space and coating quality of the small-drift-diameter straight pipe and various special-shaped pipe fittings, effectively ensures the coating quality of the anticorrosive paint, and is beneficial to realizing corrosion protection of the metal pipeline.
Drawings
FIG. 1 is a schematic flow chart of a method for fully coating an anticorrosive coating on the inner wall of a small-bore straight pipe or a special-shaped metal pipeline according to an embodiment of the invention.
FIG. 2 is a schematic diagram of the connection method of the thickness of the anticorrosive paint and the leak point detection method in the pipe when the pipe to be detected is short;
FIG. 3 is a schematic view of the connection method of the thickness of the anticorrosive paint and the leak point detection method in the pipe when the pipe to be detected is long.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. In addition, the technical features involved in the embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other. The present invention will be described in further detail with reference to specific embodiments.
As a preferred embodiment of the present invention, as shown in fig. 1, the present invention provides a method for fully coating an anticorrosive coating on an inner wall of a small-bore straight pipe or a special-shaped metal pipeline, comprising the following steps:
s1, processing the inner surface of a pipeline:
for a small-drift-diameter straight pipe and various special-shaped metal pipes, after the pipes are received, an electronic endoscope is used for carrying out internal inspection on the pipeline, and then a liquid sand blasting method is adopted for carrying out inner surface treatment on the pipeline; preferably, the metal pipe is made of any one of red copper, copper alloy, common steel, stainless steel and titanium alloy, and the stainless steel is preferably duplex stainless steel; the grinding fluid used for liquid sand blasting is a mixture of water and white corundum (the mixing mass ratio is 7. The inside of the pipeline is cleaned by chemical or physical methods if the inside of the pipeline has fouling such as marine life and the like. When the pipeline is long, a method of spraying sand by liquid at two ends is adopted, and the sand spraying time is prolonged according to the situation. After liquid sandblasts, sand grains and other impurities inside the pipeline are cleaned by a high-pressure water gun immediately, and then the pipeline is dried by a high-speed blower.
After the surface treatment is carried out by adopting the method, the cleanliness of the metal surface should reach the derusting grade standard of Sa2.5, namely, the steel surface should not have visible attachments such as grease, dirt, oxide skin, rust, paint coating and the like, and any residual mark should be only a slight punctiform or strip-shaped color spot. The inside of a straight pipe with the drift diameter less than 32mm and all special pipes are inspected through an electronic endoscope, and the surface is ensured to reach the rust removal grade standard of Sa2.5. When the surface has visible grease, the grease can be removed by using surfactant or detergent (preferably non-film forming type) with the concentration of 5-10%, and the grease must be completely dried after treatment. The roughness value after the metal surface treatment is preferably more than 5 μm.
After the surface treatment of the pipe is qualified, the surface dust is removed by compressed air or clean rag, and the coating link is waited to enter.
S2, coating and detecting the pipeline, comprising the following substeps:
s2.1, preparing the anticorrosive paint on site (including but not limited to epoxy enamel, which is explained by taking the epoxy enamel as an example):
the preparation of the on-site epoxy enamel is strictly operated by technicians according to the product use instructions, and the prepared epoxy enamel is filtered for 2 times by a 200-mesh clean copper filter screen and then used.
The prepared epoxy enamel needs to be kept stand for 20min, and can be used after the temperature is reduced to about 40 ℃ and the epoxy enamel is obviously pulled into a line. In cold environment, the epoxy enamel should be kept still in warm water at about 45 ℃ for heat preservation. The prepared epoxy enamel paint is used within 2h, and when dry and thick, 10-40% of diluent can be added for continuous use.
S2.2, judging whether the requirements of the coating process are met:
the pipeline after finishing the surface treatment must be coated with No. 1 epoxy enamel on the same day to prevent the secondary oxidation of the metal surface. When the 1 st coating cannot be carried out on the day, secondary sand blasting or polishing is required before the 1 st epoxy magnetic paint is coated subsequently.
S2.3, judging whether the coating environment condition is met:
a hygrometer and a thermometer must be equipped on site.
(1) When the relative humidity exceeds 85%, coating cannot be performed.
(2) To ensure drying of the coated surface, "dew point management" should be employed for coating. Before coating, the dew point of air and the temperature of the surface to be coated were measured, and when the temperature of the surface to be coated was higher than the dew point by 3 ℃, it was confirmed that the surface was dry and could be coated. The temperature of the surface of the pipeline is measured by an infrared thermometer. When the temperature of the surface of the pipeline is higher than the dew point and is lower than 3 ℃ or the temperature is lower than 10 ℃, the coating is not suitable.
(3) The coating is preferably carried out at the temperature of 15-40 ℃, and the coating construction unit ensures the temperature environment suitable for coating.
S2.4, performing a coating process on the inner wall of the pipe fitting according to the following steps:
for straight pipes and all special pipes with the drift diameters less than 32mm, the inner walls of the pipelines are sprayed, and after spraying, the inner walls of the pipelines are brushed by rolling brushes in flexible shafts, so that the adhesive force of enamel is improved, and sagging is cleaned in time. And (3) adopting an electronic endoscope to carry out internal inspection on the pipeline in the interval period of each paint, and entering the next paint after repairing and polishing the macroscopic leaking points and the sagging. The total thickness of the paint film after finishing coating is more than 300 mu m.
Preferably, in step S2.4, after the previous paint is completely dried, the next epoxy enamel is applied, and the time interval between each paint is generally not less than 24 hours. When the temperature is low, the humidity is high and the drying speed is low, the actual drying time of the epoxy enamel is prolonged according to the circumstances, or the drying speed of the epoxy enamel is accelerated by measures of strengthening pipeline ventilation, improving the conditions of the temperature and the humidity on the spot and the like. If the thickness of a certain paint film does not reach the standard, one paint is added.
Preferably, after the step S2.4, the coated pipe opening is temporarily coated by adopting a wrapping and anti-collision material properly, so that the completeness of the paint surface before handing over, transporting and installing the real ship is ensured.
S3, checking and accepting:
for all the coated pipelines, detecting a paint film on the inner wall of the pipeline by using an electric spark detector, searching a fine leakage point or a part with the thickness of the paint film being less than 300 mu m, and re-coating until the paint film reaches the standard;
performing spot check on the thickness of a paint film on the inner wall of the same batch of pre-delivered pipe fittings, wherein the qualification rate of the spot check is 100%;
detecting the paint film covering quality of the inner wall of the pipeline by using an electric spark detector for the inner wall of the same batch of pre-delivered pipe fittings, wherein the quality of the paint film covering quality of the inner wall of the pipeline is required to be 100 percent;
when both the two items are met, the acceptance is qualified.
The following describes in detail a method for detecting the thickness and leakage points of the anticorrosive paint in the small-drift-diameter straight pipe or special-shaped metal pipe used in the inspection and acceptance S3, and an electric spark detector is used for detecting the thickness and leakage points of the anticorrosive paint in the straight pipe or special-shaped metal pipe with the drift diameter smaller than 32 mm. The metal pipe is made of any one of red copper, copper alloy, common steel, stainless steel and titanium alloy.
Basic principle of the electric spark detector: the metal surface insulating anticorrosive coating is too thin, the resistance value and the air gap density at iron leakage and electric leakage micro-holes are very small, when high voltage passes through, air gaps are formed to be punctured to generate spark discharge, a pulse signal is generated for an alarm circuit, and an alarm gives out sound and light alarm, so that the aim of detecting the anticorrosive coating is fulfilled according to the principle.
The electric spark detector consists of three parts, including main machine, high pressure gun and probe. The host is internally provided with a microcomputer circuit, an audible and visual alarm device, a high-energy battery pack and the like; the high-pressure gun comprises a metal plug, a connecting multi-core wire, a built-in electronic high-pressure generator, a high-pressure output switch and the like; the probe is a conductive metal spherical braided fabric probe.
The method for detecting the thickness and the leakage points of the epoxy enamel on the inner wall of each special-shaped metal pipeline by the electric spark detector comprises the following steps:
and S3.1, before detection, connecting a metal plug bayonet on a high-pressure gun connecting line of the electric spark detector with a host high-pressure output socket bayonet, inserting the metal plug bayonet in a corresponding way, rotating the metal plug bayonet clockwise, and sensing that a clamping phenomenon exists, namely good contact is achieved.
S3.2, when the detected pipeline is short, as shown in figure 2, adopting a first wiring scheme: the connecting magnet is placed at the position without a coating at the tail end of the pipeline, one end of a short grounding wire is connected to the connecting magnet, the other end of the short grounding wire is grounded, one end of a long grounding wire is connected to the connecting magnet, and the other end of the long grounding wire is connected to a binding post of a host machine.
When the measured pipeline is long, as shown in fig. 3, the second wiring scheme: the connecting magnet is placed at the position without a coating at the tail end of the pipeline, one end of a short grounding wire is connected to the connecting magnet, the other end of the short grounding wire is grounded, one end of a long grounding wire is connected to a binding post of a host, and the other end of the long grounding wire is connected to a grounding rod and is dragged and detected on the ground. Preferably, if the ground on which the test is located is dry, the ground rod of the long ground line is inserted into the ground instead when carrying out step S3.2 wiring scheme two, in order to reduce the ground resistance.
S3.3, mounting the probe at the top end of the high-pressure gun; preferably, in step S3.3, the probe is a conductive metal spherical braid probe.
S3.4, selecting a test voltage according to the thickness of the anti-corrosion coating to be required, and adjusting the output voltage of the electric spark detector to the test voltage;
the test voltage was selected as follows:
1) When the average thickness of the anticorrosive coating is more than 0.5mm,
U＝7900T 1/2
2) When the average thickness of the anticorrosive coating is less than or equal to 0.5mm,
U＝3300T 1/2 or U = T5V/μm
Where U-test voltage, unit: v;
t-average thickness of anticorrosive coating, unit: mm;
preferably, in step S3.4, the method for adjusting the output voltage of the electric spark detector is as follows:
the tester turns on the power switch, wears the high-voltage glove, presses the high-voltage output button, the microcomputer in the electric spark detector automatically changes, the power supply voltage indicator lights out, the output high-voltage indicator lights out, the liquid crystal meter head displays and converts the output high-voltage value, and adjusts the output knob to enable the display value to be the required test voltage (preferably, after the electric spark detector finishes each detection, the output adjusting knob is adjusted to be minimum; and (4) loosening the high-voltage output button, and enabling the electric spark detector to be in a standby working state.
S3.5, trying to enable the conductive metal spherical braided fabric probe to approach or touch a measured object conductor (the conductive metal spherical braided fabric probe cannot be short-circuited so as to prevent the instrument from being damaged by over-discharging of a load), if a discharge spark can be seen and an acousto-optic alarm is given, and if the acousto-optic alarm disappears correspondingly when the conductive metal spherical braided fabric probe leaves the measured object, the instrument works normally, and then the detection can be started.
S3.6, respectively inserting the conductive metal spherical braided fabric probes into the pipeline from two ends of the special-shaped metal pipeline to detect an anticorrosive coating, wherein the anticorrosive coating comprises but is not limited to epoxy enamel, and detecting whether an audible and visual alarm is given or not; preferably, in step S3.3, if necessary, a flexible connection is adopted between the conductive metal spherical braid probe and the high pressure gun to ensure that the probe can detect all parts inside the special-shaped metal pipeline.
And S3.7, when all the parts in the pipeline are detected and no sound-light alarm is generated, judging that the epoxy enamel coating in the pipeline has no leakage point and the thickness of the coating meets the corrosion protection requirement.
Preferably, step S3.7 is further included after step S3.6, that is, after the detection is finished, the switches of the electric spark detector are restored to the original state; after the power supply is turned off, the conductive metal spherical braided fabric probe and the grounding wire of the host machine are directly subjected to short-circuit discharge and then are stored.
It will be appreciated that the embodiments of the system described above are merely illustrative, in that elements illustrated as separate components may or may not be physically separate, may be located in one place, or may be distributed over different network elements. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of this embodiment. One of ordinary skill in the art can understand and implement it without inventive effort.
In addition, it should be understood by those skilled in the art that, in the specification of the embodiments of the present invention, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrases "comprising a," "8230," "8230," or "comprising" does not exclude the presence of additional like elements in a process, method, article, or apparatus that comprises the element.
In the description of the embodiments of the invention, numerous specific details are set forth. It is understood, however, that embodiments of the invention may be practiced without these specific details. In some instances, well-known methods, structures and techniques have not been shown in detail in order not to obscure an understanding of this description. Similarly, it should be appreciated that in the foregoing description of exemplary embodiments of the invention, various features of the embodiments of the invention are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure and aiding in the understanding of one or more of the various inventive aspects.
However, the disclosed method should not be interpreted as reflecting an intention that: that is, the claimed embodiments of the invention require more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive aspects lie in less than all features of a single foregoing disclosed embodiment. Thus, the claims following the detailed description are hereby expressly incorporated into this detailed description, with each claim standing on its own as a separate embodiment of an embodiment of this invention.
Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the embodiments of the present invention, and not to limit the same; although embodiments of the present invention have been described in detail with reference to the foregoing embodiments, it should be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the spirit and scope of the technical solutions of the embodiments of the present invention.
Claims (7)
1. A method for fully coating anticorrosive paint on the inner wall of a small-drift-diameter straight pipe or a special-shaped metal pipeline is characterized by comprising the following steps:
s1, processing the inner surface of a pipeline:
for a straight pipe or a special-shaped metal pipe with the pipe fitting drift diameter smaller than 32mm, after the pipe is received, an electronic endoscope is used for carrying out internal inspection on the pipeline, then the inner surface treatment of the pipeline is carried out by adopting a liquid sand blasting method, grinding fluid used in liquid sand blasting is a mixture of water and white corundum, wherein the mixing mass ratio is 7;
cleaning the interior of the pipeline immediately after liquid sand blasting, and then drying the pipeline;
after the treatment and acceptance of the inner surface of the pipeline are qualified, removing surface dust, and waiting for entering a coating link;
s2, coating and detecting the pipeline, comprising the following substeps:
s2.1, preparing the anticorrosive paint on site;
s2.2, judging whether the requirements of the coating process are met;
s2.3, judging whether the coating environment condition is met;
s2.4, performing a coating process on the inner wall of the pipe fitting according to the following steps:
the inner wall of the pipeline is sprayed, and after spraying, the inner wall is subjected to rolling brushing by using a flexible shaft inner rolling brush, so that the adhesive force of enamel is improved, and sagging is cleaned in time; performing internal inspection on the pipeline by using an electronic endoscope in the interval period of each paint, performing supplementary coating on macroscopic leakage points and polishing the convection current hanger, and then performing next painting; the total thickness of the paint film after coating is more than 300 mu m;
step S2.4, after the previous paint is completely dried, brushing the next anticorrosive paint, wherein the interval time of each paint is not less than 24 hours;
after the step S2.4, temporarily coating the pipe orifice of the coated pipe fitting by using a binding and anti-collision material to ensure the completeness of the paint surface before handing over, transportation and installation of a real ship;
s3, checking and accepting:
for all the coated pipelines, detecting a paint film on the inner wall of the pipeline by using an electric spark detector, searching a leakage point or a part of which the thickness of the paint film is less than 300 mu m, and re-coating until the paint film reaches the standard;
performing spot check on the thickness of a paint film on the inner wall of the same batch of pre-delivered pipe fittings, wherein the qualification rate of the spot check reaches 100%;
detecting the paint film covering quality of the inner wall of the pipeline by using an electric spark detector for the inner wall of the same batch of pre-delivered pipe fittings, wherein the electric spark detector is required to be incapable of generating sparks, and the qualification rate of spot inspection reaches 100%;
when the two items are both satisfied, the acceptance is qualified;
in the checking and acceptance step S3, the step of detecting the thickness and leakage points of the anticorrosive paint inside the straight pipe or the special-shaped metal pipeline with the drift diameter smaller than 32mm by using an electric spark detector comprises the following steps:
s3.1, before detection, connecting a metal plug bayonet on a high-pressure gun connecting line of the electric spark detector with a host high-pressure output socket bayonet;
s3.2, a first wiring scheme: placing a connecting magnet at the position without a coating at the tail end of the pipeline, connecting one end of a short grounding wire to the connecting magnet, grounding the other end of the short grounding wire, connecting one end of a long grounding wire to the connecting magnet, and connecting the other end of the long grounding wire to a binding post of a host machine;
alternatively, the first and second liquid crystal display panels may be,
and a second wiring scheme: placing a connecting magnet at the position without a coating at the tail end of the pipeline, connecting one end of a short grounding wire to the connecting magnet, grounding the other end of the short grounding wire, connecting one end of a long grounding wire to a binding post of a host machine, and connecting the other end of the long grounding wire to a grounding rod to drag and detect on the ground;
s3.3, mounting the probe at the top end of the high-pressure gun; the probe adopts a conductive metal spherical braided fabric probe, and the probe is flexibly connected with the high-pressure gun;
and S3.4, selecting a test voltage according to the thickness of the anticorrosive coating to be achieved, and adjusting the output voltage of the electric spark detector to the test voltage.
2. The method for fully coating the anticorrosive paint on the inner wall of the small-drift-diameter straight pipe or the special-shaped metal pipeline according to claim 1, characterized by comprising the following steps of:
in the step S1, the conditions for qualified treatment and acceptance of the inner surface of the pipeline are as follows: the inner surface reaches the rust removal grade standard of Sa2.5, and the roughness value is more than 5 mu m;
when the surface has visible grease, the grease is removed by a cleaning agent, and the grease must be thoroughly dried after treatment.
3. The method for fully coating the anticorrosive paint on the inner wall of the small-drift-diameter straight pipe or the special-shaped metal pipeline according to claim 1, characterized by comprising the following steps of:
in a step S2.1, the data is transmitted,
the preparation of the on-site anticorrosive paint is strictly operated according to the product use specification, and the prepared anticorrosive paint is used after being filtered by a clean copper filter screen.
4. The method for fully coating the anticorrosive paint on the inner wall of the small-drift-diameter straight pipe or the special-shaped metal pipeline according to claim 3, wherein the method comprises the following steps:
in a step S2.1, the first step,
standing the prepared anticorrosive paint for a preset time, and using the prepared anticorrosive paint after the temperature is reduced to a preset temperature and the anticorrosive paint is pulled into a line; the prepared anticorrosive paint is used within 2h, and can be continuously used after a diluent is added when the prepared anticorrosive paint is dry and thick.
5. The method for fully coating the anticorrosive paint on the inner wall of the small-drift-diameter straight pipe or the special-shaped metal pipeline according to claim 1, wherein the method comprises the following steps:
in step S2.2, the requirements for the coating process are satisfied as follows:
(1) The pipeline after finishing surface treatment must be brushed with the 1 st path of anticorrosive paint on the same day to prevent the secondary oxidation of the metal surface;
(2) When the No. 1 coating cannot be carried out in the day, secondary sand blasting or grinding is required before the No. 1 anticorrosive coating is coated subsequently.
6. The method for fully coating the anticorrosive paint on the inner wall of the small-drift-diameter straight pipe or the special-shaped metal pipeline according to claim 1, characterized by comprising the following steps of:
in step S2.3, the coating environmental conditions are:
(1) When the relative humidity exceeds 85%, the paint cannot be coated;
(2) In order to ensure the drying of the coating surface, the coating adopts dew point management; before coating, measuring the dew point of air and the temperature of the coated surface, and when the temperature of the coated surface is higher than the dew point by more than 3 ℃, confirming that the surface is dry and can be coated; when the temperature of the coated surface is lower than the dew point by 3 ℃ or the air temperature is lower than 10 ℃, the coating is not required;
(3) The coating is carried out at the temperature of 15-40 ℃.
7. The method for fully coating the anticorrosive paint on the inner wall of the small-drift-diameter straight pipe or the special-shaped metal pipeline according to claim 1, characterized by comprising the following steps of:
the metal pipe is made of any one of red copper, copper alloy, common steel, stainless steel and titanium alloy.
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| CN202010803052.8A CN111992474B (en) | 2020-08-11 | 2020-08-11 | Full-coating method of anticorrosive paint for inner wall of small-drift-diameter straight pipe or special-shaped metal pipeline |
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| CN202010803052.8A CN111992474B (en) | 2020-08-11 | 2020-08-11 | Full-coating method of anticorrosive paint for inner wall of small-drift-diameter straight pipe or special-shaped metal pipeline |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5202157A (en) * | 1990-08-28 | 1993-04-13 | Mitsui Petrochemical Industries, Ltd. | Method for lining internal surfaces of pipelines |
| JP3188495B2 (en) * | 1991-03-15 | 2001-07-16 | 昭 神谷 | Rehabilitation method of drain pipe inner surface |
| IT1280119B1 (en) * | 1995-01-31 | 1998-01-05 | Delle Vedove Impianti Srl | CONTINUOUS PAINTING PROCESS OF MOVING ELEMENTS AND RELATED DEVICE |
| JP2005313092A (en) * | 2004-04-28 | 2005-11-10 | Pcg Tekunika:Kk | Pipe lining device and pipe lining method |
| CN102989650A (en) * | 2011-09-13 | 2013-03-27 | 胜利油田胜利石油化工建设有限责任公司 | Construction method for performing inner anti-corrosion on long pipe section by liquid coating |
| CN102671828A (en) * | 2012-05-22 | 2012-09-19 | 美的集团有限公司 | In-pipe painting machine and painting method |
| CN102773207A (en) * | 2012-08-15 | 2012-11-14 | 黄石新兴管业有限公司 | Spraying process method and device for inner wall of small-caliber nodular cast iron pipe |
| CN106140515B (en) * | 2016-08-30 | 2019-05-17 | 潍坊亿斯特管业科技有限公司 | A kind of caliber pipe inwall erosion resistant coating spray equipment and technique |
| CN108144827A (en) * | 2017-11-30 | 2018-06-12 | 扬州安泰威合金硬面科技有限公司 | Caliber pipe inwall ni base alloy coating prepares production method |
| CN109986471A (en) * | 2018-10-11 | 2019-07-09 | 马付林 | A kind of long range surface treatment of inner wall of steel pipe and coated lining anti-corrosion method |
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