JPH0826463B2 - Metal tube surface treatment method and apparatus - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method and an apparatus for performing a metal pipe surface treatment in two stages using a chemical conversion treatment liquid containing an inorganic ion in the chemical conversion treatment of a metal pipe surface.

[Conventional technology]

Metal pipes with plastic coatings are mainly used as pipelines for transporting fluids such as gas and crude oil and as offshore structures. Most of these applications are used under severe corrosive environmental conditions.
~ 50 years of long-term durability is required. In order to satisfy this requirement, as is well known, it is indispensable to subject the surface of the metal tube to an appropriate surface treatment before the plastic coating.

There are various surface treatment methods depending on the use of the metal tube, required characteristics, etc., but a method using a chemical conversion treatment liquid containing chromium ions is frequently used. Specifically, as described in JP-A-62-294183, the treatment liquid blown out from a nozzle is sprayed on the surface of the metal tube that has been blasted to simultaneously remove dust on the metal pipe surface and apply the treatment liquid. Then, the ironing device is used to make the coating amount uniform. Here, in the case of only coating, in addition to spraying with a nozzle, various methods such as a roll coater method and an appropriate amount dropping method can be considered, but in any method, the unattached treatment liquid is recovered, The liquid is reused immediately after removing dust contained in the liquid with a magnet separator or the like.

[Problems to be Solved by the Invention]

Next, the problems of the conventional undercoating will be listed below.

The method described in JP-A-62-294183 basically forms a chemical conversion treatment film with the chemical conversion treatment liquid remaining on the surface of the metal pipe while cleaning the surface of the metal pipe with the chemical conversion treatment liquid. .

In this method, the basis weight of the chemical conversion treatment liquid may depend on the conditions under which the chemical conversion treatment liquid is sprayed for dust removal and cleaning of the metal tube surface. Therefore, it may be difficult to secure a coating amount of the chemical conversion treatment liquid that exhibits a sufficient chemical conversion treatment effect while performing effective dust removal and cleaning.

According to the method disclosed in JP-A-62-294183, it is possible to simultaneously perform cleaning of the surface of the metal tube and surface treatment, but the treatment liquid itself is contaminated due to reuse of the treatment liquid that has not adhered. Is not necessarily inevitable. This is because it is considered impossible to completely remove dust even if the dust removal action is performed by using a magnet separator or the like.

Therefore, by repeating the recovery and reuse of the non-adhered treatment liquid for a long time, the treatment liquid becomes contaminated and deteriorates, and the liquid is applied to the surface of the metal tube. Therefore, the original performance of the chemical conversion treatment liquid is maintained. There is a possibility that it may not be able to fully exert its effect.

Further, with respect to the above problems, if the amount of non-adhered liquid is reduced by controlling the amount of spraying by a nozzle to prevent the liquid from being contaminated or deteriorated, the cleaning effect on the surface of the metal pipe is significantly reduced, and As is apparent from the above-mentioned problems, it may be difficult to secure an appropriate basis weight of the chemical conversion treatment liquid.

When discarding the treatment liquid, it is necessary to take out the liquid to the outside of the piping system, but since the treatment liquid contains heavy metals, there is an environmental problem.

The present invention pays attention to the above-mentioned problems in the prior art, effectively cleans the surface of the metal pipe, and always applies a clean chemical conversion treatment solution at an appropriate basis weight, and further facilitates disposal of the treatment solution. An object of the present invention is to provide a method and an apparatus for treating a metal tube surface.

[Means for solving the problem]

FIG. 1 is a block diagram showing an outline of an apparatus configuration for carrying out the method of the present invention in one aspect. Hereinafter, the first chemical conversion treatment liquid and the second chemical conversion treatment liquid are referred to as a cleaning liquid and a coating liquid, respectively.

In FIG. 1, the first-stage chemical conversion treatment apparatus A is the apparatus at the upper right of the figure, and includes two cleaning liquid supply tanks 1, a cleaning liquid supply pump 2 for spraying the cleaning liquid onto the metal pipe 3, and a cleaning liquid sprayed on the metal pipe 3. It comprises a cleaning liquid recovery tank 4 for recovering the remaining non-adhered cleaning liquid, and a cleaning liquid recovery pump 6 for recovering the recovered non-adhered cleaning liquid to the cleaning liquid supply tank 1 via a filter 5.

The second-stage chemical conversion treatment device B is the device at the upper left of FIG. 1, and includes two coating liquid supply tanks 7, a coating liquid supply pump 8 for applying the coating liquid to the metal pipe 3 after cleaning, The coating liquid recovery tank 16 for collecting the remaining non-adhering coating liquid of the applied coating liquid, and the collected non-adhering coating liquid
It is composed of a coating liquid recovery pump 10 for transferring the coating liquid to the coating liquid regenerating tank 9 via.

The lower device in FIG. 1 is a regeneration treatment device C, which is a cleaning liquid regeneration tank 11 for recovering the cleaning liquid which is contaminated and deteriorated in the cleaning liquid supply tank 1 via a cleaning liquid transfer pump 12.
And a cleaning liquid regeneration pump 13 for transferring the contaminated and deteriorated cleaning liquid accumulated in the cleaning liquid regeneration tank 11, and the contaminants transferred through the filter 5 by the cleaning liquid regeneration pump 13 and all the ions in the deteriorated cleaning liquid are removed. And an ion exchange device 14 for converting to pure water, a pure water storage tank 15 for collecting the cleaning liquid which has become pure water by passing through the ion exchange device 14, the pure water and the coating liquid regeneration tank 9. The cleaning liquid preparation tank 17 which prepares the coating liquid accumulated in 9 and becomes the cleaning liquid again, the pure water pump 20 for transferring the pure water to the cleaning liquid preparation tank 17, and the coating liquid regeneration tank 9 It comprises a coating liquid regeneration pump 18 for transferring the coating liquid to the cleaning liquid preparation tank 17, and a cleaning liquid preparation pump 19 for transferring the cleaning liquid prepared in the cleaning liquid preparation tank 17 to the cleaning liquid supply tank 1.

In the above configuration, the cleaning liquid supply tank 1 of the first-stage chemical conversion treatment device A, which is the cleaning liquid supply / recovery device, may be one, and the second-stage chemical conversion treatment device B, which is the coating liquid supply / recovery device.
The number of the coating liquid supply tank 7 may be one.

[Action]

As described above, according to the metal pipe surface treatment method of the present invention, the cleaning liquid prepared in the cleaning liquid supply tank 1 of the first-stage chemical conversion treatment apparatus A and having a low concentration is supplied to the metal pipe 3 by the cleaning liquid supply pump 2. Then, the non-adhered cleaning liquid is sent back to the cleaning liquid supply tank 1 via the filter 5 and the cleaning liquid recovery pump 6, and is repeatedly used until the cleaning liquid is contaminated and deteriorated. Meanwhile, in the second-stage chemical conversion treatment apparatus B, which is a coating liquid supply / recovery device, the coating liquid transferred from the coating liquid supply tank 7 is applied to the cleaned metal tube 3 via the coating liquid supply pump 8. . The coating liquid used for coating is used only once, and the coating liquid that has not adhered is a coating liquid recovery tank.
It is collected in 16 and is sent to the coating liquid regeneration tank 9 via the filter 5 and the coating liquid recovery pump 10.

Next, these unadhered coating liquids are repeatedly used until they become contaminated and deteriorated as described above, and then a cleaning liquid that has been purified by ion exchange is mixed and used again as a cleaning liquid. In the processing device C, the contaminated and deteriorated cleaning liquid is sent to the cleaning liquid regeneration tank 11 by the cleaning liquid transfer pump 12. The cleaning liquid in the cleaning liquid regenerating tank 11 is further filtered by the cleaning liquid regenerating pump 13 into a filter 5 and an ion exchange device.
It is separated into pure water and a precipitate through 14 and the pure water is stored in a pure water storage tank 15.

Here, when the liquid stored in the pure water storage tank 15 has not been sufficiently ion-exchanged and cannot be regarded as pure water, the liquid is purified by the pure water pump 20 and the cleaning liquid regeneration tank 11 is used.
Sent to the cleaning solution regeneration pump 13 again to filter 5
And it is sent to the pure water storage tank 15 through the ion exchange device 14.

The pure water generated as described above is sent from the pure water storage tank 15 to the cleaning liquid preparation tank 17 by the pure water pump 20. In the cleaning liquid preparation tank 17, the pure water and the non-adhered coating liquid sent from the coating liquid regeneration tank 9 via the coating liquid regeneration pump 18 are mixed, and again as a cleaning liquid via the cleaning liquid preparation pump 19 It is sent to the supply tank 1.

As described above, the metal pipe surface treatment method of the present invention is used by forming a so-called closed pipe system. In addition, as described above, the solution accumulated in the pure water storage tank 15 by being ion-exchanged by the ion exchange device 14 into pure water and the coating solution accumulated in the coating solution regenerating tank 9 are mixed to form a cleaning solution again. In this case, there may be a case where the pure water which is the pure water and is accumulated in the pure water storage tank 15 is insufficient and cannot be mixed to a predetermined concentration. In that case, purified water or distilled water may be used together as a solvent. Further, the concentrations of the cleaning liquid and the coating liquid may be appropriately adjusted depending on the purpose of the chemical conversion treatment, the application, etc. Further, when no abnormality is observed in the performance of the chemical conversion treatment film, the cleaning liquid and the coating liquid are different from each other. It may be a solution, or the composition of the cleaning liquid and the coating liquid may be different.

〔The invention's effect〕

The present invention, as described above, the chemical conversion treatment liquid containing inorganic ions is separately used from the beginning into a cleaning liquid and a coating liquid each having an appropriate concentration, the coating liquid is used only once, and the non-adhering coating liquid is Since a so-called closed piping system is used, in which pure water separated from the deteriorated cleaning liquid using an ion exchange device can be prepared and used again as a cleaning liquid, a healthy coating liquid is always used without waste. In addition, the effect of the chemical conversion treatment on the surface of the metal tube can be sufficiently exhibited regardless of the spraying conditions of the cleaning liquid.

In addition, the conventional problem of disposal of harmful treatment liquid is solved, and it is extremely effective in preventing environmental pollution.

[Brief description of drawings]

FIG. 1 is a block diagram showing an outline of a device configuration for implementing the present invention in one aspect. A: First-stage chemical conversion treatment device, B: Second-stage chemical conversion treatment device C: Regeneration treatment device 1: Cleaning liquid supply tank, 2: Cleaning liquid supply pump 3: Metal tube, 4: Cleaning liquid recovery tank 5: Filter, 6: Cleaning solution recovery pump 7: Coating solution supply tank, 8: Coating solution supply pump 9: Coating solution regeneration tank, 10: Coating solution recovery pump 11: Cleaning solution regeneration tank, 12: Cleaning solution transfer pump 13: Cleaning solution regeneration pump, 14: Ion exchange Device 15: Pure water storage tank, 16: Coating liquid recovery tank 17: Cleaning liquid preparation tank, 18: Coating liquid regeneration pump 19: Cleaning liquid preparation pump, 20: Pure water pump

Claims (3)

[Claims] 1. A metal tube surface treatment method in which a step of applying a plastic coating to the surface of a metal tube is the step of subjecting the surface of the metal tube subjected to the blasting treatment to a surface treatment using a chemical conversion treatment liquid containing inorganic ions. The surface of the metal tube is cleaned using the first chemical conversion treatment liquid obtained by diluting the second chemical conversion treatment liquid which is the coating liquid,
Next, in the step of the second step, a metal tube surface treatment method characterized by a two-step surface treatment in which the second chemical conversion treatment liquid is applied to the surface of the metal tube. 2. A metal tube surface treatment method in which, in the step of applying a plastic coating to the surface of the metal tube, the surface of the blasted metal tube is subjected to a base treatment using a chemical conversion treatment liquid containing inorganic ions. The surface of the metal pipe is washed with the first chemical conversion treatment liquid obtained by diluting the second chemical conversion treatment liquid, which is a coating liquid, and then the second chemical conversion treatment liquid is applied to the surface of the metal pipe in the second step. At this time, after collecting and reusing the first chemical conversion treatment liquid that has not adhered to the metal pipe surface, the contaminated and deteriorated first chemical conversion treatment liquid is made into pure water using an ion exchange resin, while the metal pipe surface is The second chemical conversion treatment liquid not adhered to is collected and mixed with the pure water, and again used for the metal pipe surface treatment as the first chemical conversion treatment liquid, so that the chemical conversion treatment liquid does not leak outside, in a closed pipe system. Metal tube surface treatment method characterized by treatment . 3. A metal pipe surface treatment apparatus for subjecting a blasted metal pipe surface to a base treatment using a chemical conversion treatment liquid containing inorganic ions in the step of applying a plastic coating to the surface of the metal pipe. The surface of the metal pipe is washed with the first chemical conversion treatment liquid obtained by diluting the second chemical conversion treatment liquid, which is a coating liquid, and then the second chemical conversion treatment liquid is applied to the surface of the metal pipe in the second step. At this time, a first chemical conversion treatment device for supplying the first chemical conversion treatment liquid to the metal pipe surface and collecting and reusing the first chemical conversion treatment liquid not attached to the metal pipe surface; and a second chemical conversion treatment. A liquid is supplied to the surface of the metal pipe, and a second-stage chemical conversion treatment device for collecting the second chemical conversion treatment liquid that is not attached to the surface of the metal pipe, and the supply and the collection are repeated by the first chemical conversion treatment device, A method for converting the contaminated or deteriorated first chemical conversion treatment liquid into pure water. Resin exchange device, and the pure water is mixed with the recovered second chemical conversion treatment liquid and used again as the first chemical conversion treatment liquid and is supplied to the first-stage chemical conversion treatment device. The chemical conversion treatment liquid does not leak outside. A metal pipe surface treatment apparatus comprising: