JPH0353030B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a method for applying a resin lining to the inner surface of a narrow-mouthed container. [Prior Art] Examples of narrow-mouth metal containers include pressure tanks, cylinders, drum cans, etc. Among them, cylinders are well known. The cylinders are made of high-grade materials with excellent corrosion resistance, and the inner surface is covered with a corrosion-resistant film, in order to fill corrosive gases and liquids, or gases and liquids that require purity. It has been known. However, cylinders made from high-quality materials such as stainless steel are about the same size as regular products.
The drawback is that it is 10 to 15 times more expensive. In addition, the coating applied to the inner surface of the cylinder has a thickness of 0.6 to 1.0 mm or more, which has no pinholes and completely blocks contact between the cylinder inner surface material and the filling material, and is bonded to the inner surface material, making it resistant to internal and external pressure and impact. It is necessary to have physical properties that are strong enough to prevent deformation and peeling, and that are not attacked by fillers, but conventional coatings such as tar and epoxy for internal coatings must be applied as a solution with a solvent, dried, and
The thickness of the film is formed through repeated curing processes, and usually one process requires about 6 hours, and the maximum thickness formed is about 0.07 mm, and if you try to make a thicker layer in one process, it will cause sagging. , causing bubbles, etc. It is clear that with a cylinder shape that only has a small-diameter entrance and exit, the drying and curing time due to atmospheric dispersion is slower than normal cylinders, and it takes a lot of time to achieve the required thickness without pinholes, and the thicker the cylinder Film peeling may occur due to impact, etc. Instead of such a film, a metal plating coating can be considered, but the inner surface of the cylinder cannot be subjected to post-treatment such as surface polishing, and pinholes cannot be eliminated. If there is even one pinhole, erosion will spread from that area and peeling of the film will occur, resulting in damage due to corrosion and deterioration of purity. Thus, conventional coated products have not been satisfactory. [Problem to be Solved by the Invention] Therefore, the present inventors have developed various narrow-mouth containers such as cylinders that can be manufactured at low cost and have a corrosion-resistant film of a predetermined thickness and no pinholes on the inner surface. As a result of our research, we developed a narrow-mouth container with a resin lining film formed by adhering and melting powdered resins such as PE, PP, fluorine, nylon, epoxy, and vinyl chloride on the inner surface. This narrow-mouth container can be manufactured at low cost by simply applying a corrosion-resistant coating to the inner surface of a conventional material without using high-grade materials.The thickness of the coating can be changed freely and pinholes do not occur.The coating can be formed in a short time. It is possible to do this and requires less man-hours, so productivity is higher than conventional coated products.Since there is no contamination with impurities due to corrosion, there is no need for a cleaning process, which is a prerequisite for refilling.
There are advantages such as Incidentally, it has been known to apply powder resin lining to the outer surface of articles and the inner and outer surfaces of large-diameter pipes, etc., and the method involves immersing a preheated coating in suspended powder. There is a fluidized dipping method that forms a film, an electrostatic coating method that electrostatically attaches the powder to the coating, and a thermal spraying method that passes the powder through a flame to a semi-molten state and sprays it onto the coating. However, it cannot be used for lining the inner surface of a cylinder that has only a small opening/exit portion with an inner diameter of 20 to 25 mm called a cap. In other words, it is impossible to supply powder into the cylinder using the fluidized immersion method, and even with the electrostatic coating method or thermal spraying method, it is practically impossible to insert a spray gun into the cylinder and spray the powder uniformly over the entire inner surface. It's impossible. In addition to these methods, there is also a method in which the coating is filled with powder resin, heated and rotated to melt and adhere the resin near the inner surface, and then discharges the excess resin.
This is known as shown in Japanese Patent Application Laid-open No. 76153/1983.
However, it is difficult to obtain satisfactory results even when this method is used for lining the inner surface of a cylinder with a narrow neck. In other words, it takes an extremely long time to supply powdered resin into the cylinder through the small-diameter entrance and exit, and it also takes a long time to take out the excess powder, resulting in uneven film thickness. There is also a risk of powder clogging due to fusion at some parts, and furthermore, unmelted powdered resin adheres to the surface, making it difficult to obtain a smooth surface. Furthermore, depending on the state of tilted rotation, there is a possibility that the film thickness will be non-uniform, and there are many restrictions on the positional relationship between the opening of the container, the axis of rotation, etc. Furthermore,
When heating a cylinder filled with powder from the outside,
Temperature unevenness tends to occur due to differences in the wall thickness of the cylinder, which results in differences in the thickness of the molten film, making it difficult to secure a satisfactory film. As described above, it is difficult to use the conventional powder resin lining method for lining the inner surface of the cylinder. The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a resin lining method capable of applying a uniform powder resin lining to the inner surface of a narrow-mouthed container such as a cylinder. [Means for Solving the Problems] The resin lining method of the present invention prepares a narrow-mouth container whose inner surface is to be lined, uniformly heats the entire container, and lines the inner surface of the container with a predetermined thickness. Weigh the amount of powdered resin equivalent to the composition, put it into a pressure-feeding tank, apply compressed air to one end of the pressure-feeded tank, use the compressed air to push out the powdered resin from the other end of the pressure-feeded tank, and other methods. The supplied powder is fed under pressure into the narrow-mouthed container through a pipe connected to the end side in a short period of time, and then the attitude of the container is sequentially changed so that the powder inside the container almost evenly contacts the entire area of the inner surface of the container. It is characterized by melting and adhering the entire amount of resin. [Function] According to the above method, the amount of powder resin supplied into the narrow-mouthed container is only the amount necessary for forming a lining film of a predetermined thickness, and specifically, it is about 10 to 20% of the internal volume of the container. It can be supplied quickly, and there is no need to take out excess resin, so powder clogging does not occur. However, when supplying powdered resin, a predetermined amount of powder is weighed and put into a pressure-feeding tank, compressed air is sent into one end of the tank, and the air is used to push the powder out of the other end of the pressure-feeding tank. Since powdered resin is fed under pressure into a narrow-mouthed container through a connected pipe, the powdered resin can be supplied all at once in a short period of time, and almost no powder fusion occurs during the resin supplying. By changing the position sequentially, a uniform and defect-free lining is obtained. Moreover, since the container is heated uniformly in advance, there is no temperature unevenness within the container, and a uniform film thickness can be formed. Furthermore, since there is only a small amount of resin in the container compared to the internal volume of the container, it is possible to change the position of the container by standing it up, lying it down, inverting it, or tilting it, and by rotating it as necessary. The resin flows well and can come into contact with the entire surface of the container, and not only adheres uniformly, but also slides as if rubbing against the inner surface, creating a smooth film with almost no surface irregularities. As described above, the method of the present invention has the advantage that a smooth powder resin lining of uniform thickness can be simply and easily applied to the inner surface of a narrow-mouthed container. [Example] Hereinafter, the present invention will be described in further detail using examples shown in the accompanying drawings. FIG. 1 shows a cylinder 1 which is to be lined on the inside. The cylinder 1 consists of a cap (entrance/exit part) 2, a bottom part 3, and a straight pipe body part 4.
A convex portion 5 is provided on the bottom portion 3. Straight pipe body 4
has a uniform thickness, but the base 2 and the bottom 3
is thicker than the straight pipe body 4. Although the cylinder 1 in FIG. 1 has been subjected to a chemical conversion treatment as a base treatment necessary for powder lining, the base treatment may be performed by other methods. Then, after being uniformly heated in a suitable heating furnace (not shown), it was placed on the heat-resistant bricks 6. Next, a predetermined amount of powdered resin 7 is supplied to the cylinder 1 shown in FIG. Here, the amount of powdered resin supplied to the cylinder 1 is an amount necessary and sufficient to line the inner surface of the cylinder with a predetermined thickness, for example, 1 mm, and an excessive amount of resin is not supplied. It is desirable to supply the powdered resin into the cylinder in as short a time as possible, and for this reason, the present invention utilizes a powder feeding method. however,
A good supply cannot be expected by simply using a conventionally known method of conveying powder by suspending it in an air stream. That is, when powder is suspended in an air stream and fed into a narrow-mouthed container, the amount of air is too large and the powder is ejected from the mouth of the container. In addition, when repeating the work of sending and stopping airflow with powder suspended in order to supply the desired amount of powder, bends, height differences, and differences in pipe inner diameter will inevitably occur in the feed supply piping. Due to such reasons, powder clogging occurs in the feed supply piping. Powder-clogged feed supply piping cannot be reused unless it is disassembled, repaired, or replaced, and if powder clogging occurs during powder supply, the supply amount cannot be confirmed and lining failure occurs. In order to compensate for these drawbacks, a powder supply device 8 shown in FIG. 5 is used in this embodiment. The powder supply device 8 is of a pressure feeding type, and includes a compressed air pipe 9,
Filter and pressure regulating valve 10, pressure feeding tank 11,
Measuring hopper 12, valve 13, feed hose 14
and a supply pipe 15. As shown in FIG. 1, the supply pipe 15 is inserted into the cylinder from the entrance/exit part 2, and is used to supply powdered resin into the cylinder without coming into contact with the entrance/exit part heated at high temperature. It is made of heat-resistant material that will not break even if it comes into contact with the heated entrance/exit part. Furthermore, supply pipe 1
The outer diameter of the cylinder 5 is set to be small enough to allow air in the cylinder to be discharged through the supply pipe and the inlet/outlet pipe when a predetermined amount of powdered resin is pumped into the cylinder in a short time. The pressure tank 11 has a size that can accommodate a predetermined amount of powdered resin fed into one cylinder 1. Powder supply by the powder supply device 8 is performed at the following capacity. That is, the amount of powdered resin necessary for film formation is measured each time by the measuring hopper 12 and supplied to the pressure feeding tank 11, and then the compressed air pipe 9
Compressed air is applied to the upper end of the pressure-feeding tank 11, and the entire amount of powder in the pressure-feeding tank 11 is pushed out from the lower end of the pressure-feeding tank 11 by the compressed air acting on the upper surface of the tank. , and feed it all at once into the cylinder from the inlet/outlet portion through the supply pipe 15 in a short period of time. In this way, a predetermined amount of powdered resin can be reliably supplied into the cylinder 1 in a short time without causing powder clogging in the middle of the piping. Table 1 shows a specific example of powder resin supply to a cylinder using the apparatus shown in FIG.

〔Effect of the invention〕

As described above, the present invention has the effect that a smooth powder resin lining of uniform thickness can be simply and easily applied to a narrow-mouth container such as a cylinder.

[Brief explanation of drawings]

Figures 1, 2, 3, and 4 show an embodiment of the method of the present invention, in which a side sectional view showing the procedure for lining a cylinder, and Figure 5 show the powder used in the above embodiment. FIG. 6 is a schematic cross-sectional view of the feeding device, FIG. 6 is a cross-sectional view of the cap used in the above embodiment, and FIG. 7 is a schematic side view of the two-axis rotary movement lining device used in another embodiment of the method of the present invention. 1...Cylinder, 2...Entrance/exit part (cap), 3...
...Bottom, 4...Straight pipe body, 5...Protrusion, 6...Heat-resistant brick, 7...Powder resin, 8...Powder supply device, 9...Compressed air pipe, 11...Pressed tank , 12...
...Measuring hopper, 14...Feeding hose, 15...
Supply pipe, 16...cap, 18...roller rotating table, 20...two-axis rotation movement lining device.

Claims (1)

[Claims] 1. Prepare a narrow-mouthed container whose inner surface is to be lined, heat the entire container uniformly, weigh out an amount of powdered resin equivalent to forming a lining of a predetermined thickness on the inner surface of the container, and transfer it to a pressure-feeding tank. compressed air is applied to one end of the pressure-feeding tank, the powdered resin is pushed out from the other end of the pressure-feeding tank with the compressed air, and is then force-fed into the narrow-mouthed container through a pipe connected to the other end in a short time. , after that, the attitude of the container is sequentially changed so that the powder inside the container is almost evenly contacted with the entire inner surface of the container, and the entire amount of supplied powder resin is melted and adhered to the container. Method.