JPS635480B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electrolytic polishing method and apparatus suitable for finishing the corrosion-resistant metal inner surface of a large cylindrical container such as a reaction container, and an equivalent relatively wide flat or curved surface. If the inner surface of the container needs to be re-polished after long-term use, the inner surface of the container, including the inner surface of the upper mirror section, can be polished with a relatively small amount of electrolytic material. The present invention relates to an on-site electrolytic polishing method and device capable of polishing using a polishing liquid.

In the chemical industry, food industry, etc., containers with inner surfaces made of corrosion-resistant steel or other corrosion-resistant metals are used to carry out various reactions or treatments, or to store liquid substances.
When the inner surface of this type of container is electrolytically polished to a mirror-like smooth surface, its non-adhesive properties will cause a reaction.
Processing is easier to carry out, and adhering residues that cause contamination are reduced and can be easily removed, helping to maintain a high level of product quality.

However, it is clearly disadvantageous to carry out electrolytic polishing by filling this type of large container with electrolyte, and it is necessary to reduce the amount of electrolyte used.
In container manufacturing factories, for example,
As disclosed in Publication No. 27439, if the inner surface of the end plate is electrolytically polished before installation, and the bottom is continuously electrolytically polished while the container is placed on the horizontal axis and rotated, the following can be achieved with a relatively small amount of liquid. All internal surfaces can be electrolytically polished.

On the other hand, there are not enough facilities available for electrolytic polishing and re-polishing of containers located in the chemical industry, etc., and it takes time and effort to remove them from the installed state and transport them to manufacturing plants for polishing. Since the effective number of days of operation will be reduced, it is desirable to establish a method that can electrolytically polish the inner surface of the container while it is in the installed state.

The method disclosed in Japanese Patent Application Laid-Open No. 51-54035 is one of the methods that enables electrolytic polishing of the inner surface of a container in an installed state.
In this method, an electrolytic solution box formed in a shape that adapts to the curved surface of each part of the inner surface of a vertically oriented cylindrical sealed container is used, and this box is open at the front, and electrolytic polishing is performed by sealing the edges of the box. The electrolytic polishing solution can be held in the box by pressing against the container part, and the top is open for overflow of the solution and the dissipation of the generated gas. The part is electrolytically polished by circulating a liquid and energized, and the possible surface is electrolytically polished while moving this in the circumferential direction and the axial direction. However, the method of using this edge-sealed box is
If the shape of the surface to be polished changes partially irregularly, or if the surface to be polished is partially interrupted due to the presence of a nozzle, etc., it becomes difficult to secure a seal, causing leakage and keeping the electrolyte in the box. Therefore, there is a fear that continuous electrolytic polishing cannot be continued. This tendency is particularly strong in the upper mirror part because there are many nozzles, etc., and the generated gas accumulates and interferes with electrolytic polishing in that part, making it difficult to polish satisfactorily.

The present invention solves these problems of the conventional method,
The present invention provides a method and an apparatus which enable electrolytic polishing to be performed even when the container is in an installed state, and which also enables easy polishing of the inner surface of the upper mirror part, which has heretofore been considered extremely difficult. The method of the present invention is also relatively simple, inexpensive and flexible in implementation equipment and requires much less electrolyte than previously, reducing costs and facilitating transportation.

Specifically, the electrolytic polishing technique of the present invention involves attaching an airtight bag, at least one surface of which is made of liquid-permeable cloth, to the inner surface of a cylindrical container to be polished, which is made of a surface of a rotating body. The sealed bag has a liquid inlet and an outlet, and is inflated by the pressure of the electrolytic polishing liquid circulated through the openings, and is supported pivotably about the axis of the container by elastic and/or rigid supports. The liquid-permeable cloth surface is pressed against the inner surface of the section so that the electrolytic polishing liquid that permeates through the cloth comes into contact with the bag. Electrolytic polishing of the segmented inner surface of the container is performed by applying electricity through the liquid, and the segmented inner surface electrolytic polishing is transferred in the circumferential direction or in the axial direction of the container to form layered area polishing, and the layered area polishing is performed to the necessary extent. The polishing surface is expanded by sequentially causing dislocation transfer in a direction intersecting the above direction.

In addition, the electrolytic polishing technique of the present invention generally involves using an elastic and/or rigid support by placing a sealed bag made of liquid-permeable cloth on at least one side of the surface to be polished close to the surface to be polished. The sealed bag is supported so as to be able to move along the surface to be polished, and the sealed bag has a liquid inlet and outlet, and is expanded by the pressure of the electrolytic polishing liquid that is circulated through both ports, and the liquid-permeable cloth surface is applied to the segmented surface of the surface to be polished. are brought into close contact with each other so that the electrolytic polishing liquid that permeates through the cloth comes into contact with the cloth, and the sealed bag has a built-in flexible electrode, and the surface to be polished is heated by passing electricity through the electrolytic polishing liquid between this electrode and the surface to be polished. perform electrolytic polishing on a segmented surface, transfer this segmented surface electrolytic polishing in a certain direction of the surface to be polished to obtain layered area polishing, and transfer said layered area polishing in a direction that intersects with said direction to the necessary extent. It is characterized by an expanded polishing surface.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to an embodiment in which the inner surface of a vertically axial cylindrical sealed container such as a reactor is electrolytically polished.

1 to 4 show an example of the apparatus used to carry out the method of the present invention on the inner surface of the upper mirror portion 2 of the vertical axis cylindrical closed container 1 to be electrolytically polished. Since this type of container usually has a stirrer shaft 3 located on the vertical axis, this can be used as a rotating shaft. However, if such an axis does not exist, it is necessary to specially provide a pivot axis at the vertical axis.

In order to support the airtight bag 4, which will be explained in detail later, split bosses 5 and 6 are fixed to the upper and lower parts of the shaft 3, and the upper split boss 5 has a set of two split bosses sandwiched at an angle of approximately 60°. A pair of radial airtight bag mounting rods 7 are arranged symmetrically with respect to the center and each is mounted so that it can be raised and lowered freely by a pin 8, and the support rod 9 is connected to the pins 10 and 11 at both ends, extending between the middle of the mounting rod 7 and the lower split boss 6. Attach by. The airtight bag support rod 7 has a curved shape similar to the cross-sectional shape of the inner surface of the upper mirror part, and is made of elastic material to provide some flexibility.The airtight bag support rod 7 can be adjusted vertically to support the airtight bag. The rod 7 is held close to the inner surface of the upper mirror at a constant distance. This support is umbrella-shaped and convenient for folding, transporting into the container through its opening, expanding and attaching, but other mechanisms may be chosen.

The airtight bag 4 is mounted over a set of mounting rods so as to enclose them, and is hermetically sealed over the entire periphery in a fan shape that spreads in the radial direction from the center. Its outer surface 12, which faces the inner surface of the upper mirror section, is made of a permeable cloth that allows liquid to seep out little by little. The opposite back surface 13 may be made of the same type of cloth, hardly permeable cloth, or non-permeable membrane. The back side 13 is provided with an inlet 14 and an outlet 15 for liquid that communicate with the inside of the bag, each having a flexible inlet tube 1.
6 and the outlet liquid pipe 17 are connected. A flexible electrode 18 is installed inside the airtight bag 4 as close to the back surface 13 as possible, and a lead wire 19 is introduced after being sealed from the outside.
Connect to. The built-in electrode 18 is made of a wire mesh made of ultra-fine wire made of copper, lead, stainless steel, etc., and has a fan shape similar to that of a sealed bag. The mesh electrode 18 can also be mounted inside the bag on the side of the outer surface 12.

The hose 16 guided toward the outer end of the airtight bag 4 is supported by a clip 20 in the middle of its drooping to reduce bending of the mounting rod 7 due to the weight of the liquid during liquid passage.

After preparing as described above, the electrolytic polishing liquid is pumped and supplied into the airtight bag 4 through the hose 16 and the inlet 14, and is caused to flow out through the outlet 15 and the hose 17 and circulated between the liquid tank and the liquid tank. The sealed bag is expanded by the pressure of the liquid inside the bag, and the outer surface 12 of the permeable cloth is brought into close contact with the corresponding section of the inner surface of the upper mirror part 2 of the container so as to conform to the curved shape there. At the same time, the electrolytic polishing liquid oozes out of the outer surface 12 of the cloth due to the pressure inside the bag and due to the capillary action of the cloth, forming a liquid film 21 between the inner surface of the upper mirror part and the outer surface of the cloth that is about to come into close contact.
The upper mirror part 2 and the electrode 18 in the bag are communicated with each other to the extent necessary and sufficient using electrolytic polishing liquid.

In this state, when the container 1 is connected to the positive side of the power source and the electrode 18 is connected to the negative side, and a direct current is passed through the electrolytic polishing liquid, an electrochemical reaction occurs on the container that is in close contact with the sealed bag. The segmented inner surface of the mirror section is electrolytically polished.

By slowly rotating the rotary shaft 3 and reversing it as necessary for the connection part, the divided area of the electrolytic polishing process in which the sealed bag is closely moved is moved in the circumferential direction of the container. The area is electropolished to a smooth, shiny surface. In this embodiment, the electrolytic polishing of the inner surface of the upper mirror part is performed all at once, but the layered zone can also be polished in two or more parts. Further, the transfer of sealed bags may be carried out continuously or may be carried out stepwise for each section.

In the electrolytic polishing according to the present invention, even if there is a slight partial change in the shape of the polishing surface, the airtight bag adheres well to it, and even if there is a nozzle, etc., the bag will not be unable to hold the liquid, and the container serving as the anode The release of gas that may be generated on the inner surface is promoted, and the hydrogen gas generated on the cathode electrode is carried away by the electrolytic solution flow and does not accumulate, making it easier to electrolytically polish the inner surface of the upper mirror, which was extremely difficult with conventional methods. Well done.

5 to 7 show an example of the apparatus used to carry out the method of the invention on the inner surface of the cylindrical body 22 of the container 1. FIG.

A sealed bag support frame 25 is attached to the tips of a pair of upper and lower support rods 23 extending radially from the central rotating shaft 3 through a seat plate 24 at a position close to the inner surface of the body. The airtight bag 26 in this example is supported on the front surface of the support frame 25, and its shape is a rectangular shape with a height equal to the length divided by the trunk portion and a width equal to the arc length divided by the trunk circumference. Its outer surface 27, which is in close contact with the dividing section of the inner surface of the part, is made of a permeable cloth and the back surface 2
Reference numeral 8 denotes a liquid inlet 29 and a liquid outlet 30 that communicate with the inside of the bag made of hardly permeable cloth or non-permeable membrane.
A flexible inlet liquid tube 31 and a flexible outlet liquid tube 32 are connected to these, respectively, and a lead wire 34 is connected to a flexible electrode 33 attached to the back surface 28 inside the bag.

The electrolytic polishing solution is pumped and circulated in the sealed bag 26, and the sealed bag is inflated by the liquid pressure to bring the outer cloth surface 27 of the bag into close contact with the inner surface of the section of the body, forming a liquid film 35 of the exuded electrolyte between the two, and then the container is closed. Then, the inner bag electrode 33 is connected to a DC power source, and the divided inner surface of the body is electrolytically polished by passing a DC current through the electrolytic polishing liquid.

Electrolytic polishing of the layered region is performed by slowly rotating the rotating shaft to move the close contact area of the sealed bag, that is, the inner surface section to be electrolytically polished, in the circumferential direction of the body;
Next, the polishing device is moved to the next layered area and electrolytic polishing is performed in the same manner, and this operation is repeated as many times as necessary to extend the polishing surface to the entire inner surface of the body.

8 to 10 show an example of an apparatus used to carry out the method of the present invention on the inner surface of the lower mirror portion 36 of the container 1. FIG.

The airtight bag 37 has the same fan shape as the airtight bag 4 used for polishing the upper mirror part, and is attached across a fan-shaped support frame 38 having a curve similar to the cross-sectional shape of the inner surface of the lower mirror part. 38 is supported in a hanging manner by a pair of support rods 39 and 40 extending diagonally downward from the rotating shaft 3, and is positioned close to the inner surface of the lower mirror section. The outer surface 41, ie, the lower surface, of the airtight bag 37 is made of a permeable cloth, and the back surface 42 is made of a hardly permeable cloth or a non-permeable membrane. Airtight bag 3
7 has a liquid inlet 43 and a liquid outlet 44 that communicate with the inside of the bag, and are connected to a flexible liquid inlet pipe 45 and a flexible liquid outlet pipe 46, respectively. A flexible electrode 47 is attached to the outer surface 41 side of the bag and a lead wire 48 is connected thereto.

Electrolytic polishing of the inner surface of the lower mirror section is carried out in the same manner as for the inner surface of the upper mirror section. That is, the sealed bag expands due to the circulation of the electrolytic polishing liquid under pressure, and the outer surface of the cloth comes into close contact with the inner surface of the section of the lower mirror part, forming a liquid film 49 between the two.
The container and the electrode are connected to a DC power source to electrolytically polish the inner surface of the section, and the inner surface of the lower mirror portion is polished by rotating the polishing section.

In either case, the liquid outlet is preferably located above the inlet, preferably at the top, in order to facilitate the discharge of hydrogen gas that may be generated within the sealed bag.

According to the present invention described above, the following effects can always be obtained.

1 The electrical connection between the inner surface of the container and the electrode via the permeable cloth by the electrolyte is necessary and sufficient, and the electrolytic polishing conditions such as current, voltage, and solution temperature can be controlled more easily than in the conventional method using an electrolyte box. There is almost no need to make any changes.

2. In the conventional method using an electrolyte box, polishing becomes impossible if the surface to be polished has uneven parts that make it difficult to hold the electrolyte in the box, but with the present invention, even such parts can be polished.

3 The cathode holder that requires edge sealing in the conventional method requires a strong pressing force to maintain the seal, which inevitably increases the weight of the device, but in the present invention, the sealed bag with a built-in cathode is held close to the surface to be polished. Since it is only necessary to do this, the weight of the device becomes lighter and transportation becomes easier.

4. Hydrogen gas generated at the cathode is discharged together with the electrolyte circulating in the sealed bag and does not accumulate in the container, so it does not interfere with electrolytic polishing.
It's also safe.

5. By making the electrodes flexible, the sealed bag with built-in electrodes can be folded, and together with a support device that can be disassembled and assembled, it can be carried in and out through a small opening in the container, such as a manhole.

6. The amount of electrolytic polishing liquid required is small.

7. Existing containers can be electrolytically polished at the site of use while still installed, and the inner surface of the upper mirror can also be polished, which previously had to be abandoned.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional side view showing the polishing state of the inner surface of the upper mirror part of a container and the apparatus according to the present invention, FIG. 2 is a top view of this apparatus, and FIG. FIG. 4 is an enlarged view of the circle frame a in FIG. 3. Fig. 5 is a side view showing the polishing state of the inner surface of the container body and the apparatus according to the present invention, Fig. 6 is a sectional view taken along line BB in Fig. 5, and Fig. 7 is an enlarged view of the area inside the circular frame b in Fig. 6. It is. FIG. 8 is a longitudinal sectional side view showing the polishing state of the inner surface of the lower mirror part of a container and the apparatus according to the present invention, FIG. 9 is a bottom view of this apparatus, and FIG. 10 is a sectional view taken along the line CC in FIG. 8. In the figure, 1 is a container, 2 is an upper mirror part, 22 is a body part, 36 is a lower mirror part, 3 is a rotating shaft, 4, 26, 37
is a sealed bag, 12, 27, 41 is its outer surface, 13,
28, 42 are the back side, 5 to 11, 23 to 25,
38 to 40 are supports, 14, 29, 43 are liquid inlets, 15, 30, 44 are liquid outlets, 16, 3
1, 45 are inlet liquid tubes, 17, 32, 46 are outlet liquid tubes, 18, 33, 47 are flexible electrodes, 19, 3
4, 48 are lead wires, 20 are clips, 21, 3
5 and 49 are liquid films.

Claims (1)

[Claims] 1. A method for electrolytically polishing the inner surface of a vertical cylindrical container having a central rotation axis while the container is in an installed state, which includes a built-in flexible electrode and at least the surface in contact with the surface to be polished. A sealed bag made of liquid-permeable cloth is used, the sealed bag is mounted and supported on a central rotating shaft in close proximity to the surface to be polished, and the electrolytic polishing solution is circulated and fed into the sealed bag. The airtight bag is inflated by pressure and the liquid-permeable cloth surface is brought into contact with the surface to be polished, so that the electrolytic polishing liquid permeates and oozes from the cloth surface to the surface to be polished, and the cathode of the DC power source is connected to the airtight bag. An inside surface of a reaction vessel characterized by connecting an anode to a flexible electrode inside the container and applying electricity between the two electrodes, and at any time driving a central rotating shaft to move a sealed bag and electrolytically polish the inside surface of the container. Electrolytic polishing methods such as 2. An electrolytic polishing device for electrolytically polishing the inner surface of a vertical cylindrical container having a central rotation axis while it is in an installed state, which is characterized by comprising the following components: a. An electropolishing liquid inlet, a guide an airtight bag having an outlet, at least one surface of which is made of liquid-permeable cloth, and incorporating a flexible electrode separated from the cloth; b. an electrolytic polishing bag into the airtight bag through the inlet and outlet; c) a means for supporting the sealed bag on a central rotating shaft with the surface of the liquid-permeable cloth close to the surface to be polished; and d) a means for distributing the liquid between the two electrodes with the container as an anode and the flexible electrode as a cathode. a means for applying a DC voltage to; e) inflating the sealed bag by the feeding pressure of the electrolytic polishing liquid to press the liquid-permeable cloth against the surface to be polished; in this state, applying electricity between the two electrodes; The inner surface of the container is electrolytically polished through the electrolytic polishing liquid exuding from the liquid-permeable cloth by driving the airtight bag to move the sealed bag. 3. The electrolytic polishing apparatus according to claim 2, wherein the sealed bag has a foldable structure.