A metal tube inner wall electrolytic rust removal device and process

Abstract

The application provides a metal pipe inner wall electrolytic rust removal device and process, the device comprises a fixed distance movement system, a cleaning liquid supply system and an electrolysis system; the fixed distance movement system comprises a fixed distance rod; one end of the fixed distance rod is provided with an auxiliary cathode, and the other end is connected to a driving motor; the cleaning liquid supply system comprises a tee pipe with an elbow and an overflow pipe; the elbow part of the tee pipe extends into the inlet of the metal pipe to be treated; the other two inlets of the tee pipe are respectively provided with a seawater valve and a clean water valve; the end of the fixed distance rod provided with the auxiliary electrode penetrates through the elbow part of the tee pipe and extends into the metal pipe; the overflow pipe is installed at the outlet of the metal pipe; the electrolysis system comprises a constant current power supply, the negative electrode of the constant current power supply is connected to the auxiliary cathode, and the positive electrode of the constant current power supply is connected to the metal pipe. The application solves the problems of incomplete removal of corrosion products and environmental unfriendliness existing in the traditional metal pipe inner wall rust removal process.

Description

Technical Field

[0001] This invention relates to the field of rust removal and polishing technology, and more particularly to an electrostatic rust removal device and process for the inner wall of a metal pipe. Background Technology

[0002] During production and operation, the deposition of corrosion products on the inner wall of metal pipes can easily lead to intensified under-deposit corrosion and decreased heat exchange performance. Therefore, it is often necessary to remove corrosion products from the inner wall of metal pipes during maintenance to ensure their subsequent application. However, metal pipes often have small diameters and large length-to-diameter ratios, making conventional cleaning processes difficult to implement. Currently, there are two main processes for removing corrosion products from the inner wall of metal pipes: chemical and physical methods. Chemical methods mainly use chemical cleaning solutions to clean the inner wall. Physical methods generally use a long metal shaft to drive a brush head or grinding wheel to rotate and rub the inner wall of the pipe, generating cutting force to remove corrosion products. Patent CN109504975B discloses a rust remover that does not contain hydrochloric acid, and the formula uses organic acids to reduce the generation of acid mist. However, the formulation of the agent is complex, and the agent contains chromic anhydride, which poses a hazard to the environment and human health. Patent CN112338728B discloses a handheld rust removal device. This method uses a large device, which is less effective at removing rust from the inner wall of slender metal pipes.

[0003] In summary, existing technologies and processes for removing corrosion products have significant shortcomings. Chemical cleaning methods often employ complex formulations, posing environmental pollution problems, and the acid pickling process generates acid fumes, affecting operational safety. Furthermore, chemical methods require strict control of the dosage; excessive dosage can corrode the substrate, while insufficient dosage will fail to achieve the desired rust removal effect. Physical rust removal methods, due to limitations in the structure of brush heads or grinding wheels, cannot achieve deep cleaning of corrosion products within complex corrosion pits. Mechanical cutting is insufficient to remove dense oxide films and corrosion products within corrosion pits, negatively impacting subsequent operation or repair.

[0004] Existing technologies and processes for removing corrosion products from the inner walls of metal pipes cannot simultaneously achieve both environmental friendliness and treatment effectiveness. There is an urgent need to design a simple, environmentally friendly, and highly efficient rust removal device and process for the inner walls of metal pipes to deeply remove corrosion products and improve the service performance of copper alloy pipes. Summary of the Invention

[0005] Traditional rust removal processes used to remove corrosion products from the inner walls of metal pipes have technical problems such as incomplete removal of corrosion products and environmental unfriendliness. Therefore, an electrolytic rust removal device and process for the inner walls of metal pipes is provided. The device uses natural seawater or artificially prepared NaCl solution, which is simple in composition, non-corrosive to the substrate, and environmentally friendly, as the electrolyte. Combined with specific operating processes and parameters, it can achieve efficient and thorough cleaning and rust removal of the inner walls of metal pipes.

[0006] The technical means employed in this invention are as follows:

[0007] An electrolytic rust removal device for the inner wall of a metal pipe includes a fixed-distance motion system, a cleaning fluid supply system, and an electrolysis system;

[0008] The fixed-distance running system includes a fixed-distance rod with a scale; one end of the fixed-distance rod is provided with an auxiliary cathode, and the other end is connected to a drive motor, which is used to drive the fixed-distance rod to perform linear motion;

[0009] The cleaning fluid supply system includes a tee pipe with an elbow and an overflow pipe. The elbow of the tee pipe has an inlet that extends into the inlet of the metal pipe to be treated. The other two inlets of the tee pipe are respectively equipped with a seawater valve and a clean water valve. The seawater valve is connected to a seawater pump in a seawater tank, and the clean water valve is connected to a clean water pump in a clean water tank. One end of the spacer rod, on which the auxiliary electrode is mounted, passes through the elbow of the tee pipe and extends into the metal pipe. The auxiliary electrode is supported within the metal pipe by a central support. The support includes a support body with an electrode mounting hole and a solution flow hole. The auxiliary electrode is mounted in the electrode mounting hole, and the solution flow hole connects the internal spaces of the metal pipes on both sides of the support. An overflow pipe is installed at the outlet of the metal pipe, and the other end of the overflow pipe connects to the seawater tank. The overflow pipe has a bypass pipe with an external drain valve installed on it.

[0010] The electrolysis system includes a constant current power supply, the negative terminal of which is connected to the auxiliary cathode via a negative electrode wire, and the positive terminal of which is connected to the metal tube via a positive electrode wire.

[0011] Furthermore, the elbow of the tee pipe is sealed to the metal pipe by an annular airbag; the spacer rod passes through the tee pipe through the opening on the side of the elbow, and the spacer rod and the opening on the side of the elbow are sealed by a rubber gasket; the overflow pipe is sealed to the metal pipe by an annular airbag.

[0012] Furthermore, the spacer rod and the bracket body are made of PVC or PP.

[0013] Furthermore, the auxiliary cathode is a rod-shaped electrode made of metal or carbon.

[0014] Furthermore, the annular airbag and the annular airbag have the same structure, both including an annular airbag body. The annular airbag body is inflated through an air inlet pipe and an air inlet valve, thereby achieving a seal between the three-way pipe and the overflow pipe and the metal pipe. The material of the annular airbag body is latex or rubber.

[0015] Furthermore, the metal tube is a copper-nickel alloy tube, a carbon steel tube, a stainless steel tube, or a titanium alloy tube.

[0016] The present invention also provides a rust removal process using the aforementioned electrostatic rust removal device for the inner wall of a metal pipe, specifically including the following steps:

[0017] Step 1: Open the seawater valve and seawater pump, close the drain valve, fill the metal pipe to be treated with seawater through the seawater pump and keep the seawater circulating through the overflow pipe, control the seawater flow rate to 1m / s-5m / s, and the seawater in the seawater tank is natural seawater or artificially prepared NaCl solution with a mass fraction of greater than or equal to 3.5%;

[0018] Step 2: First, install the auxiliary cathode at the inlet of the metal tube, connect the metal tube to the positive terminal of the constant current power supply, turn on the constant current power supply, and adjust the anode current density to 5A / dm² according to the degree of corrosion of the metal tube. 2 -15A / dm 2 Electrolytic derusting begins; during the electrolytic derusting process, the auxiliary cathode is controlled by a drive motor to move linearly from the inlet to the outlet inside the metal tube, and the movement speed is controlled between 1cm / min and 50cm / min.

[0019] Step 3: When the auxiliary cathode moves to the outlet of the metal tube, the electrolytic rust removal ends. Keep the metal tube flushed with seawater for 1-5 minutes to remove electrolytic byproducts, then close the seawater valve and seawater pump.

[0020] Step 4: Open the clean water valve, clean water pump and drain valve, and use clean water to rinse the metal pipe to remove residual seawater inside the metal pipe.

[0021] The present invention provides an electrolytic rust removal device and process for the inner wall of metal pipes. It utilizes artificially prepared sodium chloride or natural seawater as the electrolyte, and treats corrosion products on the inner wall of the metal pipe through acidification and dissolution at the anode surface. This not only removes the dense corrosion product film on the surface but also deeply cleans complex corrosion products inside corrosion pits. Since the electrolysis of the metal pipe in seawater produces the byproduct CuCl, adjusting the seawater flow rate after electrolysis to flush away the byproduct improves the cleaning cleanliness. This rust removal process is more efficient, provides thorough cleaning, is environmentally friendly, and can effectively reduce rust removal costs by using locally sourced materials.

[0022] Compared with the prior art, the beneficial effects of the present invention are:

[0023] 1. The electrostatic rust removal device provided by the present invention is simple to operate and can perform electrostatic rust removal and cleaning on the inner wall of slender tubes of different sizes by using auxiliary cathodes of different diameters and lengths.

[0024] 2. The electrostatic rust removal device provided by the present invention allows the auxiliary cathode to penetrate deep into the metal pipe via a drive motor for precise, automated, and continuous electrostatic rust removal; alternatively, the position of the auxiliary cathode can be controlled by a spacer rod to perform electrostatic rust removal on local pipes, achieving thorough cleaning of specific areas.

[0025] 3. The electrolyte used in this invention is natural seawater or artificially prepared NaCl solution. Through acidification and dissolution of the anodic surface of the inner wall of the alloy tube, the complex corrosion products inside the corrosion pit are deeply removed. The rust removal process causes little damage to the substrate and is safe and controllable. At the same time, the cleaning solution has good environmental friendliness. The residue of electrolysis and rinsing media has no adverse effect on the operation of the subsequent pipeline system and can be normally introduced into the pipeline system.

[0026] Based on the above reasons, this invention can be widely promoted in the field of rust removal and polishing. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a schematic diagram of the electrostatic rust removal device provided by the present invention.

[0029] Figure 2 This is a schematic diagram of the support structure described in this invention.

[0030] Figure 3 This is a schematic diagram of the annular airbag structure described in this invention.

[0031] Figure 4 This is a schematic diagram of the inner wall of the pipe before rust removal in Example 1.

[0032] Figure 5 This is a schematic diagram of the inner wall of the pipe after rust removal in Example 1.

[0033] In the diagram: 1. Auxiliary cathode; 2. Spacing rod; 3. Support; 4. Drive motor; 5. T-junction with elbow; 6a, 6b: Annular airbag; 7a. Seawater valve; 7b. Clean water valve; 8a. Seawater pump; 8b. Clean water pump; 9. Overflow pipe; 10a. Seawater tank; 10b. Clean water tank; 11. Sealing gasket; 12. Negative electrode wire; 13. Positive electrode wire; 14. Constant current power supply; 15. Metal pipe; 16. Exhaust valve; 301. Support body; 302. Electrode mounting hole; 303. Solution flow hole; 601. Airbag body; 602. Inlet pipe; 603. Inlet valve. Detailed Implementation

[0034] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0035] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0036] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0037] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of the invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0038] In the description of this invention, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is generally based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this invention and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this invention. The directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0039] For ease of description, spatial relative terms such as "above," "over," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation besides the orientation of the device as described in the figures. For example, if the device in the figures is inverted, a device described as "above" or "above" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0040] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this invention.

[0041] like Figure 1-3As shown, the present invention provides an electrolytic rust removal device for the inner wall of a metal pipe, comprising a fixed-distance motion system, a cleaning fluid supply system, and an electrolysis system;

[0042] The fixed-distance running system includes a fixed-distance rod 2 with a scale; one end of the fixed-distance rod 2 is provided with an auxiliary cathode 1, and the other end is connected to a drive motor 4, which is used to drive the fixed-distance rod 2 to perform linear motion.

[0043] The cleaning fluid supply system includes a tee pipe 5 with an elbow and an overflow pipe 9. The elbow of the tee pipe 5 has an inlet, which extends into the inlet of the metal pipe 15 to be treated. The other two inlets of the tee pipe 5 are respectively equipped with a seawater valve 7a and a clean water valve 7b, allowing for the switching between seawater and clean water entering the metal pipe 15. The seawater valve 7a is connected to a seawater pump 8a in a seawater tank 10a, and the clean water valve 7b is connected to a clean water pump 8b in a clean water tank 10b. One end of the spacer rod 2, with the auxiliary electrode 1, passes through the elbow of the tee pipe 5 and extends into the metal pipe 15. The auxiliary electrode 1... The metal tube 15 is supported by a central bracket 3. The bracket 3 includes a bracket body 301, on which electrode mounting holes 302 and solution flow holes 303 are provided. The auxiliary electrode 1 is installed in the electrode mounting holes 301. The solution flow holes 303 are used to connect the internal spaces of the metal tube 15 on both sides of the bracket 3. An overflow pipe 9 is installed at the outlet of the metal tube 15. The other end of the overflow pipe 9 is connected to the seawater tank 10a. The overflow pipe 9 is used to collect the circulating seawater in the metal tube into the seawater tank 10a. The overflow pipe 9 is provided with a bypass pipe, and an external discharge valve 16 is installed on the bypass pipe.

[0044] The electrolysis system includes a constant current power supply 14, the negative terminal of which is connected to the auxiliary cathode 1 via a negative electrode wire 12, and the positive terminal of which is connected to the metal tube 15 via a positive electrode wire 13.

[0045] Furthermore, the drive motor 4 can drive the auxiliary cathode 1 to maintain a uniform linear motion within the metal tube 15, and control the motion speed to be 0m / min-1m / min; the distance the auxiliary cathode 1 extends into the metal tube 15 can be conveniently controlled by the scale set on the distance rod 2.

[0046] Furthermore, the elbow portion of the tee pipe 5 is sealed to the metal pipe by an annular airbag 6a; the spacer rod 2 passes through the opening on the side of the elbow portion of the tee pipe 5, and the spacer rod 2 and the opening on the side of the elbow portion of the tee pipe 5 are sealed by a rubber gasket 11; the overflow pipe 9 is sealed to the metal pipe by an annular airbag 6b.

[0047] Furthermore, the spacer rod 2 and the bracket body 301 are made of insulating materials such as PVC or PP.

[0048] Furthermore, the auxiliary cathode 1 is a rod-shaped electrode made of conductive materials such as metal or carbon.

[0049] Furthermore, the annular airbag 6a and the annular airbag 6b have the same structure, both including an annular airbag body 601. The annular airbag body 601 is inflated through the air inlet pipe 602 and the air inlet valve 603, thereby achieving a seal between the three-way pipe 5 and the overflow pipe 9 and the metal pipe 15. The material of the annular airbag body 601 is latex or rubber.

[0050] Furthermore, the metal tube 15 is a copper-nickel alloy tube, carbon steel tube, stainless steel tube, or titanium alloy tube, etc.

[0051] The present invention also provides a rust removal process using the aforementioned electrostatic rust removal device for the inner wall of a metal pipe, specifically including the following steps:

[0052] Step 1: Open seawater valve 7a and seawater pump 8a, close the external discharge valve 16, fill the metal pipe 15 to be treated with seawater through seawater pump 8a and keep the seawater circulating through overflow pipe 9, control the seawater flow rate to 1m / s-5m / s, and the seawater in seawater tank 10a is natural seawater or artificially prepared NaCl solution with a mass fraction greater than or equal to 3.5%.

[0053] Step 2: First, install the auxiliary cathode 1 at the inlet of the metal tube 15. Connect the metal tube 15 to the positive terminal of the constant current power supply 14. Turn on the constant current power supply 14 and adjust the anode current density to 5A / dm² according to the degree of corrosion of the metal tube 15. 2 -15A / dm 2 Electrolytic derusting begins; during the electrolytic derusting process, the auxiliary cathode 1 is controlled by the drive motor 4 to move linearly from the inlet to the outlet in the metal tube 15, and the movement speed is controlled between 1cm / min and 50cm / min.

[0054] Step 3: When the auxiliary cathode 1 moves to the outlet of the metal tube 15, the electrolytic rust removal ends. Keep the seawater circulating and flushing the metal tube 15 for 1-5 minutes to remove the electrolytic byproducts. Then close the seawater valve 7a and the seawater pump 8a.

[0055] Step 4: Open the clean water valve 7b, the clean water pump 8b and the drain valve 16, and use clean water to rinse the metal pipe 15 to remove any residual seawater inside the metal pipe 15.

[0056] Example 1

[0057] Based on the above technical solution, in the electrostatic rust removal device described in this embodiment, the spacer rod 2 is made of PVC, the auxiliary cathode 1 is a carbon rod with a length of 5cm and a diameter of 1cm, and the support 3 is made of PVC.

[0058] Using the electrostatic rust removal device described in this embodiment and the electrostatic rust removal process provided by this invention, a rust removal device with dimensions of Φ20×2×1000mm, an inner wall rust grade of C, and a surface condition as shown in the figure is applied. Figure 4 The B30 copper-nickel alloy pipe shown undergoes electrolytic rust removal, specifically including the following steps:

[0059] Step 1: Open seawater valve 7a and seawater pump 8a, close the external discharge valve 16, fill the copper-nickel alloy tube to be treated with 3.5% NaCl artificial seawater through seawater pump 8a and keep the seawater circulating through overflow pipe 9, and control the seawater flow rate to 2m / s.

[0060] Step 2: First, install the auxiliary cathode 1 at the inlet of the copper-nickel alloy tube. Connect the copper-nickel alloy tube to the positive terminal of the constant current power supply 14. Turn on the constant current power supply 14. Based on the length of the auxiliary cathode 1 being 5cm, calculate the corresponding surface area of ​​the inner wall of the tube as 25.12cm². 2 Adjust the current density at the anode to 10 A / dm³. 2 Adjust the current value of the constant current power supply to 2.512A, and control the auxiliary cathode 1 to move linearly from the inlet to the outlet in the copper-nickel alloy tube through the drive motor 4, and control the movement speed to 5cm / min.

[0061] Step 3: When the auxiliary cathode 1 moves to the outlet of the copper-nickel alloy tube, the electrolytic derusting is completed. Adjust the seawater flow rate to 5 m / s and keep the seawater circulating to rinse the copper-nickel alloy tube for 2 minutes to remove electrolytic byproducts. Then close the seawater valve 7a and the seawater pump 8a.

[0062] Step 4: Open the clean water valve 7b, clean water pump 8b and drain valve 16, and use clean water to rinse the copper-nickel alloy pipe to remove residual seawater inside the copper-nickel alloy pipe.

[0063] After rust removal is completed, it can be observed that the corrosion products on the inner wall of the treated pipe have been completely removed. Figure 5 As shown, the inner wall exhibits a silvery-white metallic luster, which is the color of a fresh B30 copper-nickel alloy substrate.

[0064] Example 2

[0065] This embodiment uses the electrostatic rust removal device from Embodiment 1 and the electrostatic rust removal process provided by the present invention to perform electrostatic rust removal on a B10 copper-nickel alloy pipe with a pipe specification of Φ25×2×1500mm and a pipe corrosion grade of D (common pitting corrosion). The specific steps include:

[0066] Step 1: Open seawater valve 7a and seawater pump 8a, close external discharge valve 16, fill the copper-nickel alloy pipe to be treated with natural seawater through seawater pump 8a and keep the seawater circulating through overflow pipe 9, and control the seawater flow rate to 2m / s.

[0067] Step 2: First, install the auxiliary cathode 1 at the inlet of the copper-nickel alloy tube. Connect the copper-nickel alloy tube to the positive terminal of the constant current power supply 14. Turn on the constant current power supply 14. Based on the length of the auxiliary cathode 1 being 5cm, calculate the corresponding surface area of ​​the inner wall of the tube as 25.12cm². 2 Adjust the current density at the anode to 15 A / dm³. 2 Adjust the current value of the constant current power supply to 3.768A, and control the auxiliary cathode 1 to move linearly from the inlet to the outlet in the copper-nickel alloy tube by driving motor 4, and control the movement speed to 3cm / min.

[0068] Step 3: When the auxiliary cathode 1 moves to the outlet of the copper-nickel alloy tube, the electrolytic derusting is completed. Adjust the seawater flow rate to 5 m / s and keep the seawater circulating to rinse the copper-nickel alloy tube for 2 minutes to remove electrolytic byproducts. Then close the seawater valve 7a and the seawater pump 8a.

[0069] Step 4: Open the clean water valve 7b, clean water pump 8b and drain valve 16, and use clean water to rinse the copper-nickel alloy pipe to remove residual seawater inside the copper-nickel alloy pipe.

[0070] After treatment, rinsing with clean water revealed a metallic luster on the inner wall of the pipe, exposing the pits that were covered by corrosion products before treatment. This made it easier to observe the corrosion morphology and carry out subsequent protective treatment.

[0071] Example 3

[0072] This embodiment uses the electrostatic rust removal device from Embodiment 1 and the electrostatic rust removal process provided by the present invention to perform electrostatic rust removal on a carbon steel pipe with a pipe specification of Φ25×2×1000mm and a pipe corrosion grade of D (common pitting corrosion). The specific steps include:

[0073] Step 1: Open seawater valve 7a and seawater pump 8a, close the external discharge valve 16, fill the carbon steel pipe to be treated with natural seawater through seawater pump 8a and keep the seawater circulating through overflow pipe 9, and control the seawater flow rate to 2m / s.

[0074] Step 2: First, install the auxiliary cathode 1 at the inlet of the carbon steel pipe. Connect the carbon steel pipe to the positive terminal of the constant current power supply 14 and turn on the constant current power supply 14. Based on the length of the auxiliary cathode 1 being 5cm, calculate the corresponding surface area of ​​the inner wall of the pipe to be 25.12cm². 2 The current density at the anode during rust removal is 15 A / dm³. 2 Adjust the current value of the constant current power supply to 3.768A, and control the auxiliary cathode 1 to move linearly from the inlet to the outlet in the carbon steel tube through the drive motor 4, and control the movement speed to 10cm / min.

[0075] Step 3: When the auxiliary cathode 1 moves to the outlet of the carbon steel pipe, the electrolytic rust removal ends. Adjust the seawater flow rate to 5 m / s and keep the seawater circulating to rinse the carbon steel pipe for 2 minutes to remove electrolytic byproducts. Then close the seawater valve 7a and the seawater pump 8a.

[0076] Step 4: Open the clean water valve 7b, clean water pump 8b and drain valve 16, and use clean water to rinse the carbon steel pipe to remove residual seawater inside the carbon steel pipe.

[0077] After the treatment was completed, rinsing with clean water revealed a metallic luster on the inner wall of the carbon steel pipe, exposing the pits that were covered by corrosion products before the treatment. This made it easy to observe the corrosion morphology and carry out subsequent protective treatment.

[0078] Example 4

[0079] This embodiment uses the electrostatic rust removal device from Embodiment 1 and the electrostatic rust removal process provided by the present invention to perform electrostatic rust removal on a stainless steel pipe with a pipe specification of Φ30×2.5×1000mm and a pipe rust grade of B (localized coverage of corrosion products and pitting corrosion). The specific steps include:

[0080] Step 1: Open seawater valve 7a and seawater pump 8a, close the external discharge valve 16, fill the stainless steel pipe to be treated with natural seawater through seawater pump 8a and keep the seawater circulating through overflow pipe 9, and control the seawater flow rate to 2m / s.

[0081] Step 2: First, install the auxiliary cathode 1 at the inlet of the stainless steel tube. Connect the stainless steel tube to the positive terminal of the constant current power supply 14 and turn on the constant current power supply 14. Based on the length of the auxiliary cathode 1 being 10cm, calculate the corresponding surface area of ​​the inner wall of the tube as 78.5cm². 2 The current density at the anode during rust removal is 10 A / dm³. 2 Adjust the current value of the constant current power supply to 7.85A, and control the auxiliary cathode 1 to move linearly from the inlet to the outlet in the stainless steel tube through the drive motor 4, and control the movement speed to 5cm / min.

[0082] Step 3: When the auxiliary cathode 1 moves to the outlet of the stainless steel tube, the electrolytic rust removal ends. Adjust the seawater flow rate to 5 m / s and keep the seawater circulating to rinse the stainless steel tube for 2 minutes to remove electrolytic byproducts. Then close the seawater valve 7a and the seawater pump 8a.

[0083] Step 4: Open the clean water valve 7b, clean water pump 8b and drain valve 16, and rinse the stainless steel pipe with clean water to remove residual seawater inside the stainless steel pipe.

[0084] After the treatment was completed, rinsing with clean water revealed that the corrosion products on the inner wall of the stainless steel pipe were removed, and the pits that were covered by corrosion products before the treatment were exposed, which made it easier to observe the corrosion morphology and carry out repair work on the severely damaged parts.

[0085] Example 5

[0086] This embodiment uses the electrostatic rust removal device from Embodiment 1 and the electrostatic rust removal process provided by the present invention to perform electrostatic rust removal on a titanium alloy pipe with pipe specifications of Φ35×2×1000mm and a rust grade of A (partial area covered with corrosion products). The specific steps include:

[0087] Step 1: Open seawater valve 7a and seawater pump 8a, close the external discharge valve 16, fill the titanium alloy tube to be treated with artificial seawater (artificially prepared 3.5% NaCl solution) through seawater pump 8a, and keep the artificial seawater circulating through overflow pipe 9, controlling the flow rate of artificial seawater to 2m / s;

[0088] Step 2: First, install the auxiliary cathode 1 at the inlet of the titanium alloy tube. Connect the titanium alloy tube to the positive terminal of the constant current power supply 14 and turn on the constant current power supply 14. Based on the length of the auxiliary cathode 1 being 10cm, calculate the corresponding surface area of ​​the inner wall of the tube as 109.9cm². 2 The current density at the anode during rust removal is 15 A / dm³. 2 Adjust the current value of the constant current power supply to 16.48A, and control the auxiliary cathode 1 to move linearly from the inlet to the outlet in the titanium alloy tube through the drive motor 4, and control the movement speed to 10cm / min.

[0089] Step 3: When the auxiliary cathode 1 moves to the outlet of the titanium alloy tube, the electrolytic derusting ends. Adjust the flow rate of artificial seawater to 5 m / s and keep the artificial seawater circulating to rinse the titanium alloy tube for 2 minutes to remove electrolytic byproducts. Then close the seawater valve 7a and the seawater pump 8a.

[0090] Step 4: Open the clean water valve 7b, clean water pump 8b and drain valve 16, and use clean water to rinse the titanium alloy pipe to remove residual seawater inside the titanium alloy pipe.

[0091] After treatment, rinsing with clean water revealed that corrosion products and dirt on the inner wall of the titanium alloy tube were removed, and the inner wall became uniform and smooth. This effectively improves the heat transfer efficiency of the heat transfer tube and prevents localized corrosion under the corrosion products.

[0092] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A metal pipe inner wall electrolytic derusting device, characterized in that, This includes a fixed-distance motion system, a cleaning fluid supply system, and an electrolysis system; The fixed-distance motion system includes a fixed-distance rod (2) with a scale; one end of the fixed-distance rod (2) is provided with an auxiliary cathode (1), and the other end is connected to a drive motor (4), which is used to drive the fixed-distance rod (2) to perform linear motion. The cleaning fluid supply system includes a tee pipe (5) with an elbow and an overflow pipe (9); the elbow of the tee pipe (5) is provided with an inlet, and the elbow of the tee pipe (5) extends into the inlet of the metal pipe (15) to be treated; the other two inlets of the tee pipe (5) are respectively provided with a seawater valve (7a) and a clean water valve (7b); the seawater valve (7a) is connected to the seawater pump (8a) in the seawater tank (10a), and the clean water valve (7b) is connected to the clean water pump (8b) in the clean water tank (10b); the spacer rod (2) is provided with one end of the auxiliary cathode (1) passing through the elbow of the tee pipe (5) and extending into the metal pipe (15), the auxiliary cathode (1) is provided with the auxiliary cathode (1) in the spacer rod (2). The cathode (1) is supported in the metal tube (15) by a bracket (3) in the middle; the bracket (3) includes a bracket body (301), on which an electrode mounting hole (302) and a solution flow hole (303) are provided. The auxiliary cathode (1) is installed in the electrode mounting hole (301), and the solution flow hole (303) is used to connect the internal space of the metal tube (15) on both sides of the bracket (3); an overflow pipe (9) is installed at the outlet of the metal tube (15), and the other end of the overflow pipe (9) is connected to the seawater tank (10a); the overflow pipe (9) is provided with a bypass pipe, and an external discharge valve (16) is installed on the bypass pipe. The electrolysis system includes a constant current power supply (14), the negative terminal of which is connected to the auxiliary cathode (1) via a negative electrode wire (12), and the positive terminal of which is connected to the metal tube (15) via a positive electrode wire (13).

2. The metal pipe inner wall electrolytic derusting device according to claim 1, characterized in that, The bend of the tee pipe (5) is sealed to the metal pipe by an annular airbag (6a); the spacer rod (2) passes through the opening on the side of the bend of the tee pipe (5), and the spacer rod (2) and the opening on the side of the bend of the tee pipe (5) are sealed by a rubber gasket (11); the overflow pipe (9) is sealed to the metal pipe by an annular airbag (6b).

3. The apparatus for electrolytic derusting of the inner wall of a metal pipe according to claim 1, characterized in that, The spacer rod (2) and the bracket body (301) are made of PVC or PP.

4. The apparatus for electrolytic derusting of the inner wall of a metal pipe according to claim 1, characterized in that, The auxiliary cathode (1) is a rod-shaped electrode made of metal or carbon.

5. The apparatus for electrolytic derusting of the inner wall of a metal pipe according to claim 2, characterized in that, The annular airbag (6a) and the annular airbag (6b) have the same structure, both including an annular airbag body (601). The annular airbag body (601) is inflated through an air inlet pipe (602) and an air inlet valve (603), thereby achieving a seal between the three-way pipe (5) and the overflow pipe (9) and the metal pipe (15). The material of the annular airbag body (601) is latex or rubber.

6. The metal pipe inner wall electrolytic derusting device according to claim 1, characterized in that, The metal tube (15) is a copper-nickel alloy tube, a carbon steel tube, a stainless steel tube, or a titanium alloy tube.

7. A rust removal process using the electrostatic rust removal device for the inner wall of a metal pipe as described in claim 1, characterized in that, Specifically, the following steps are included: Step 1: Open the seawater valve (7a) and the seawater pump (8a), close the drain valve (16), fill the metal pipe (15) to be treated with seawater through the seawater pump (8a) and keep the seawater circulating through the overflow pipe (9), control the seawater flow rate to be 1m / s-5m / s, and the seawater in the seawater tank (10a) is natural seawater or artificially prepared NaCl solution with a mass fraction greater than or equal to 3.5%; Step two, install the auxiliary cathode (1) at the entrance of the metal pipe (15) first, connect the metal pipe (15) to the positive pole of the constant current power supply (14), turn on the constant current power supply (14), adjust the anode current density to 5A / dm 2 -15A / dm 2 , start electrolytic rust removal; during the electrolytic rust removal process, control the auxiliary cathode (1) to move linearly from the entrance to the exit in the metal pipe (15) by driving the motor (4), and control the movement speed to be 1cm / min-50cm / min; Step 3: When the auxiliary cathode (1) moves to the outlet of the metal tube (15), the electrolytic derusting ends. Keep the seawater circulating and flushing the metal tube (15) for 1 min-5 min to remove the electrolytic byproducts, and then close the seawater valve (7a) and the seawater pump (8a). Step 4: Open the clean water valve (7b), clean water pump (8b) and drain valve (16), and use clean water to rinse the metal pipe (15) to remove residual seawater inside the metal pipe (15).

Images