JP2004195624A - Metal sticking material removing method on plate glass surface - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for simply and easily removing a metal sticking material on a plate glass surface without damaging a metal unstuck part in a state of the plate glass being installed in a building. <P>SOLUTION: This removing method of the metal sticking material formed of molten metal stuck to a surface of the plate glass, while cooled and solidified, is characterized by spraying blast media mainly composed of water soluble inorganic salt such as sodium hydrogen carbonate having the prescribed average particle size by using a straight hydraulic blast device with compressed air having prescribed pressure as an injection medium. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for removing metal deposits on a plate glass surface.
[0002]
[Prior art]
When constructing a building, construction of outer walls, exteriors, window frames, window glass, etc. is required. Such construction often involves the work of welding and fusing a metal such as a steel frame, and this work generates high-temperature molten metal. For example, the temperature of molten iron generated by welding steel frames is about 1000 ° C.
[0003]
Generally, when constructing a high-rise building, construction is performed in order from the lower floor, so that the molten metal generated and scattered during the construction of the upper floor adheres to the lower floor after completion of construction. In order to prevent this adhesion, a treatment such as covering the construction completion portion with a fireproof sheet is often performed during construction, but it is difficult to completely close the gap by this treatment.
[0004]
Since the molten metal adheres to the surface of the plate glass because of the high temperature, the surface is melted, and a part of the molten metal enters the inside of the plate glass and becomes a metal deposit that is cooled and solidified. Therefore, the metal deposit cannot be removed by wiping or the like.
[0005]
On the other hand, as a method of grinding the glass surface or peeling off the surface layer, blasting, in which solid particles (blasting media) are sprayed onto the glass at high speed, has been conventionally used. Have been proposed (see Patent Document 1) and high-pressure water injection (see Patent Document 2). However, since particles such as silica sand and feldspar have a high Mohs hardness of about 6 to 7, the surface of the plate glass (Mohs hardness: about 6.5) is likely to be damaged. In particular, there is a risk of damaging a portion where metal (iron Mohs hardness: about 4.5) is not attached to impair the appearance, and there is a problem in recovery because particles are scattered. On the other hand, if high-pressure water is injected, the glass sheet may be damaged, and the use is limited such that it cannot be used at construction sites where scattering of water is not desired. Therefore, there is a problem that there is no appropriate method other than replacing the plate glass having the above-mentioned metal deposit on the surface.
[0006]
[Patent Document 1]
JP 2000-141224 A (Claims)
[Patent Document 2]
Japanese Patent Application Laid-Open No. 10-118583 (Claims)
[0007]
[Problems to be solved by the invention]
Therefore, the present invention provides a method for easily and easily removing metal deposits on the surface of a plate glass without scratching a portion where the metal is not adhered, while the plate glass is still attached to a building. With the goal.
[0008]
[Means for Solving the Problems]
The present invention relates to a metal on the surface of a plate glass, characterized in that a metal deposit formed by adhering a molten metal to the surface of the plate glass and cooling and solidifying is removed by spraying a blast medium mainly composed of a water-soluble inorganic salt. A method for removing deposits is provided.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
In the present invention, it is preferable to use a water-soluble inorganic salt such as sodium hydrogen carbonate or calcium carbonate as the blast medium. Since these water-soluble inorganic salts have a Mohs hardness of about 2-3, which is low compared to silica sand and feldspar, even if they are sprayed onto the plate glass at high speed, the surface of the plate glass is hardly damaged, and against metal deposits Sufficient removal effect. Of these, sodium hydrogen carbonate is preferably used as the water-soluble inorganic salt. Sodium bicarbonate dissolves in water to form a weakly alkaline aqueous solution with a pH of about 8.5, so the blasting media after spraying is dissolved in water and recovered as an aqueous solution, and the metal powder present in the aqueous solution is removed by filtration or the like Can be treated as wastewater.
[0010]
Moreover, in this invention, since the average particle diameter of water-soluble inorganic salt is 0.01-0.3 mm, since a metal deposit can be removed effectively, it is preferable. If the average particle diameter exceeds 0.3 mm, there is a possibility that the particulate metal deposit cannot be completely removed, and if the average particle diameter is less than 0.01 mm, the energy for removing the metal deposit is small, This is not preferable because a sufficient removal effect may not be obtained.
[0011]
In general, when blasting is performed, blasting media is sprayed onto an object to be processed together with an ejection medium. In the present invention, it is preferable to blow the above blast media with compressed air of 0.3 to 0.8 MPa (gauge pressure, the same applies hereinafter) as an injection medium because metal deposits can be sufficiently removed. In particular, it is preferable that the pressure of the compressed air is 0.4 to 0.6 MPa because energy for removing metal deposits can be appropriately maintained. The amount of media used for blasting is preferably about ² to 6 kg / m ² . If the amount of media is too small, the collision frequency between the media particles and the metal deposits becomes small, and it takes a long time to remove the metal deposits, which is not preferable. On the other hand, if the amount of media is too large, energy given to the media particles from the ejection medium is reduced, and collision between the media particles may occur, which may reduce the efficiency of removing metal deposits. Furthermore, it is not economical because it uses a large amount of media.
[0012]
Note that a small amount of water may be added and sprayed for the purpose of preventing the media particles from being pulverized and generated by the impact of spraying. Drive blasting that does not use water at construction sites where water use is not desired, or vacuum blasting that sucks and collects the blasting media after spraying and the adhered material that has been peeled off if you want to suppress the scattering of dust. It is preferable to perform wet blasting using water. Two types of blasting devices used for spraying, the direct pressure type and the suction type, are known, but in the present invention, the direct pressure type is used from the viewpoint of giving the media particles sufficient energy for removing metal deposits. It is preferable to use it.
[0013]
In addition, the kind of plate glass which applies the method of this invention is not specifically limited, It can apply to the plate glass which has various magnitude | sizes and thickness. In particular, it is preferable to use it for an architectural plate glass produced by a float process. On the other hand, if it is used on a glass whose surface is subjected to a metal coating treatment for the purpose of cutting off ultraviolet rays or the like, the metal coating is also removed at the same time, so that the intended function may not be exhibited. Moreover, when it uses for tempered glass, since there exists a possibility that intensity | strength may deteriorate by presence of the concave-shaped adhesion trace which remains on the glass surface after removal of a metal deposit, it is unpreferable.
[0014]
Moreover, the shape of the metal deposit removed by the method of the present invention is not particularly limited, and the difficulty of removal does not change depending on the shape. According to the present invention, a molten metal having a size of about several tens of μm to 1 mm generated by metal welding or the like adheres to the surface of a plate glass, and the deposits that are cooled and solidified in a spherical shape or indefinite shape can be particularly well removed. . The method of the present invention is applied to a plate glass after being attached to a building, and an iron deposit on which molten iron generated by welding of iron adheres and solidifies by cooling, or a molten metal tin used when a glass substrate is manufactured by a float method. It is suitably used for removing tin deposits that have solidified by cooling.
[0015]
【Example】
EXAMPLES Hereinafter, although an Example (Example 1) and a comparative example (Example 2) demonstrate this invention in detail, this invention is not limited by these.
[0016]
[Example 1]
Prepared a sample of a 15mm thick plate glass cut into 20cm squares, which has about 0.1 to 0.5mm of iron deposit on the surface, which has been melted and solidified by molten iron generated by welding of steel did. The sample was sprayed with sodium hydrogen carbonate having an average particle size of 220 μm using Eco Shower SB400, which is a direct pressure blasting apparatus of Eco Global Research Institute, using 0.6 MPa compressed air as an injection medium. The amount of sodium hydrogen carbonate used was 4 kg / m ² .
[0017]
Iron deposits were completely removed from the surface of the sample after spraying, and concave deposits were observed. The portion where the iron was not adhered was observed, but there was no scratch, and the strength of the sample was sufficiently maintained even after spraying.
[0018]
[Example 2]
AC-1P which is a direct pressure blasting device of Ajiji Iron Works Co., Ltd., using a No. 6 A silica sand with a particle size of 0.07 to 0.3 mm and a compressed air of 0.4 MPa for the same sample as in Example 1. Sprayed with. The amount of No. 6 A silica sand used was 4 kg / m ² .
[0019]
Iron deposits were completely removed from the sample surface after spraying, but at the same time, countless fine scratches were observed on the entire sample surface. For this reason, the strength of the sample deteriorated and the aesthetic appearance was impaired.
[0020]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to this invention, the metal deposit | attachment on the surface of a plate glass can be removed easily and easily, without attaching a damage | wound to the part which the metal is not adhering in the state which attached the plate glass to the building. Further, the strength of the plate glass can be maintained even after the metal deposits are removed, and the aesthetic appearance is not impaired, so that the cost of replacing the plate glass can be reduced.

Claims (4)

A method for removing metal deposits on a surface of a plate glass, wherein the metal deposit formed by adhering a molten metal to the surface of the plate glass and solidifying by cooling is removed by spraying a blast medium mainly composed of a water-soluble inorganic salt. . The method for removing metal deposits on the surface of a plate glass according to claim 1, wherein the water-soluble inorganic salt is sodium hydrogen carbonate or calcium carbonate having an average particle diameter of 0.01 to 0.3 mm. The method for removing metal deposits on the surface of a plate glass according to claim 1 or 2, wherein the blasting medium is sprayed by using a direct pressure blasting apparatus using compressed air of 0.3 to 0.8 MPa as an injection medium. The said glass plate is a plate glass for construction, The metal deposit removal method of the plate glass surface in any one of Claims 1-3.