Method for producing glass article and device for producing glass article

Abstract

A method for producing a glass article, the method including: an acid cleaning step S2 in which a glass sheet G is cleaned with an acidic liquid detergent D1; rinsing steps S1, S3 in which the glass sheet G is cleaned with a rinse fluid W in an upstream-side cleaning chamber 3 and a downstream-side cleaning chamber 5 which adjoin a cleaning chamber 4 where the acid cleaning step S2 is performed; and an adjustment step in which the pH of the rinse fluid W to be used in each rinsing step S1, S3 is adjusted to 4 or less or 9 or greater.

Description

Glass article manufacturing method and glass article manufacturing device

[0001] The present invention relates to a method and an apparatus for manufacturing a glass article.

[0002] A method for manufacturing a glass article such as a glass plate includes a cleaning step in which the glass article is cleaned while being conveyed. This type of cleaning step may include an acid cleaning step in which the glass article is cleaned with an acid cleaning solution to remove dirt from the glass article (for example, Patent Document 1).

[0003] When such an acid cleaning process is performed, a rinse cleaning process may be performed in an upstream area or downstream area adjacent to the acid cleaning area where the acid cleaning process is performed, in which the glass article is washed with a rinse liquid (such as pure water).

[0004] JP 2015-105194 A

[0005] When glass articles are washed with a rinse solution in an upstream or downstream area adjacent to the area where the acid cleaning process is carried out, there is a problem that bacteria are more likely to grow in the area where the rinsing process is carried out.

[0006] If bacteria occur in the area where the rinsing process is carried out, the bacteria may adhere to the glass articles via the rinsing liquid, causing stains and other problems, which may result in poor cleaning of the glass articles.

[0007] The present invention aims to suppress the growth of bacteria in the area where the rinsing step is carried out.

[0008] (1) The present invention, which has been invented to solve the above-mentioned problems, is a method for manufacturing a glass article, comprising: an acid cleaning step in which a glass article is cleaned with an acid cleaning solution; a rinsing step in which the glass article is cleaned with a rinsing solution in at least one of an upstream area and a downstream area adjacent to the area where the acid cleaning step is carried out; and an adjusting step in which the pH of the rinsing solution used in the rinsing step is adjusted, wherein the adjusting step is characterized in that the pH of the rinsing solution is adjusted to 4 or less or 9 or more.

[0009] Bacteria often thrive in a pH range above 4 and below 9. Therefore, adjusting the pH of the rinse solution to 4 or below or 9 or above can suppress the growth of bacteria in the area where the rinse step is performed.

[0010] (2) In the configuration of (1) above, it is preferable that the rinsing step is carried out in the downstream area, and that a rinsing liquid with an adjusted pH is used in the downstream area.

[0011] In the downstream area, the acidic cleaning solution carried out with the glass articles mixes with the rinsing solution, making it particularly susceptible to the growth of bacteria. However, with the above configuration, the growth of bacteria in the downstream area can be suppressed even when the rinsing process is carried out in the downstream area.

[0012] (3) In the configuration of (1) above, it is preferable that the rinsing step is performed in both the upstream area and the downstream area, and that a rinse liquid with an adjusted pH is used in both the upstream area and the downstream area.

[0013] In this way, even if the rinsing step is performed in both the upstream and downstream areas, the generation of bacteria in both areas can be suppressed.

[0014] (4) In the configuration of (2) or (3) above, it is preferable to further include a recovery step of recovering the rinse liquid used in the rinsing step, the rinsing step including a reuse step of reusing the rinse liquid recovered in the recovery step, and the adjustment step of adjusting the pH of the rinse liquid recovered in the recovery step.

[0015] This reduces the amount of rinse liquid used while also preventing the growth of bacteria that may otherwise occur when the rinse liquid is reused.

[0016] (5) In the configuration of (4) above, it is preferable that the rinsing step is performed in both the upstream area and the downstream area, the recovery step recovers the rinse liquid used in the downstream area, the adjustment step adjusts the pH of the rinse liquid recovered from the downstream area in the recovery step, and the reuse step reuses the rinse liquid recovered from the downstream area in the recovery step and whose pH has been adjusted in the upstream area and the downstream area.

[0017] This reduces the amount of rinse liquid used and also prevents bacterial growth that occurs when the rinse liquid is reused. Furthermore, even if the rinse is performed in both the upstream and downstream areas, bacterial growth can be prevented in both areas.

[0018] (6) In the configuration of (5) above, it is preferable that in the recovery step, the rinse liquid used in the upstream area is recovered in a first recovery tank, and the rinse liquid used in the downstream area is recovered in a second recovery tank; in the adjustment step, the pH of the rinse liquid recovered in the second recovery tank is adjusted; and in the reuse step, the rinse liquid with the pH adjusted is supplied from the second recovery tank to the first recovery tank, and the rinse liquid with the pH adjusted is supplied from the first recovery tank to the upstream area, and the rinse liquid with the pH adjusted is supplied from the second recovery tank to the downstream area.

[0019] This reduces the amount of rinse liquid used and also prevents bacterial growth that occurs when the rinse liquid is reused. Furthermore, even if the rinse is performed in both the upstream and downstream areas, bacterial growth can be prevented in both areas.

[0020] (7) In any of the above (1) to (6), an alkaline cleaning step of cleaning the glass article with an alkaline cleaning solution may be further provided.

[0021] In this way, the glass article is cleaned with both the acidic cleaning solution and the alkaline cleaning solution, so that dirt on the glass article can be reliably removed.

[0022] (8) In any of the above (1) to (7), the pH of the pH-adjusted rinse liquid is preferably 9 or higher.

[0023] This more reliably prevents the generation of bacteria in the area where the rinsing step is performed.

[0024] (9) In any of the above (1) to (8), the adjusting step is preferably carried out using an alkaline aqueous solution.

[0025] In this way, the pH of the rinse liquid can be adjusted without changing the components of the rinse liquid.

[0026] (10) In any of the above (1) to (9), the acidic cleaning solution may contain an organic acid.

[0027] When the acidic cleaning solution contains an organic acid, bacteria are likely to grow when the acidic cleaning solution and the rinsing solution are mixed together. Therefore, the present invention, which can suppress the growth of bacteria, is more useful.

[0028] (11) In any of the above (1) to (10), the rinse liquid preferably does not contain a surfactant.

[0029] This makes it easier to discard the rinse solution after use.

[0030] (12) The present invention, which has been invented to solve the above-mentioned problems, is a glass article manufacturing apparatus comprising: an acid washing area in which glass articles are washed with an acid washing solution; a rinse washing area provided in at least one of an upstream area and a downstream area adjacent to the acid washing area in which the glass articles are washed with a rinse solution; and an addition device that adds a component for adjusting the pH to the rinse solution used in the rinse washing area.

[0031] In this way, the same effects as those of the corresponding configuration described above can be obtained.

[0032] According to the present invention, it is possible to suppress the generation of bacteria in the area where the rinsing step is carried out.

[0033] 1 is a cross-sectional view of a cleaning device included in a glass article manufacturing apparatus according to a first embodiment of the present invention, FIG. 2 is a flow chart of a cleaning process included in a glass article manufacturing apparatus according to a second embodiment of the present invention, and FIG. 3 is a cross-sectional view of a cleaning device included in a glass article manufacturing apparatus according to a second embodiment of the present invention.

[0034] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. Note that corresponding components in each embodiment are designated by the same reference numerals, and redundant description may be omitted. When only a portion of a configuration is described in each embodiment, the configuration of another previously described embodiment may be applied to the remaining portions of the configuration. Furthermore, in addition to the combinations of configurations explicitly stated in the description of each embodiment, configurations of multiple embodiments may be partially combined together even if not explicitly stated, provided that there is no particular problem with the combination.

[0035] First Embodiment As shown in FIG. 1, a glass article manufacturing apparatus according to a first embodiment of the present invention includes a cleaning device 1 that cleans a glass sheet G as a glass article.

[0036] The cleaning apparatus 1 includes a conveying roller 2 for conveying the glass sheet G, and a plurality of cleaning chambers 3, 4, 5, 6, and 7 provided along the conveying direction (the direction of arrow A in the drawing) of the glass sheet G. Note that the conveying device for conveying the glass sheet G is not limited to the conveying roller, and may be, for example, a belt conveyor.

[0037] Here, the glass sheet G has, for example, a thickness of 1 mm or less (preferably 0.1 mm or more and 0.7 mm or less) and a rectangular shape with one side of 300 mm or more (preferably 1 m or more and 4 m or less). The thickness and shape of the glass sheet G are not limited thereto, and may be, for example, a circular shape.

[0038] The multiple cleaning chambers 3 to 7 are, in order from the upstream side in the conveying direction of the glass sheet G, a first cleaning chamber 3, a second cleaning chamber 4, a third cleaning chamber 5, a fourth cleaning chamber 6, and a fifth cleaning chamber 7. Each of the cleaning chambers 3 to 7 defines a cleaning area for the glass sheet G.

[0039] The first cleaning chamber 3 is provided with conveying rollers 2 and a first shower nozzle 8 that supplies rinsing liquid W to the glass sheet G. The first cleaning chamber 3 is connected to a first recovery tank 10 by a pipe 9, and the rinsing liquid W that accumulates at the bottom of the first cleaning chamber 3 is recovered in the first recovery tank 10 through the pipe 9. An area where a pre-process before the cleaning process is performed communicates with the first cleaning chamber 3 through an opening 11 provided in the wall on the upstream side of the first cleaning chamber 3. Examples of the pre-process include a forming process in which an original glass sheet is formed from molten glass using an overflow downdraw method or a float method, and a cutting process in which a glass sheet G is cut out from the original glass sheet. The glass sheet G is carried into the first cleaning chamber 3 through the opening 11 by the conveying rollers 2.

[0040] The second cleaning chamber 4 is provided with conveying rollers 2 and a second shower nozzle 12 that supplies the acidic cleaning solution D1 to the glass sheet G. The second cleaning chamber 4 is connected to a second recovery tank 14 by a pipe 13, and the acidic cleaning solution D1 that has accumulated at the bottom of the second cleaning chamber 4 is recovered in the second recovery tank 14 through the pipe 13. The first cleaning chamber 3 and the second cleaning chamber 4 are communicated with each other through an opening 15 provided in a wall portion on the downstream side of the first cleaning chamber 3 (an opening provided in a wall portion on the upstream side of the second cleaning chamber 4). The glass sheet G is carried into the second cleaning chamber 4 through the opening 15 by the conveying rollers 2.

[0041] The third cleaning chamber 5 is provided with a transport roller 2 and a third shower nozzle 16 that supplies rinsing liquid W to the glass sheet G. The third cleaning chamber 5 is connected to a third recovery tank 18 by a pipe 17, and the rinsing liquid W that has accumulated at the bottom of the third cleaning chamber 5 is recovered in the third recovery tank 18 through the pipe 17. The second cleaning chamber 4 and the third cleaning chamber 5 are connected to each other by an opening 19 provided in a wall portion on the downstream side of the second cleaning chamber 4 (a wall portion on the upstream side of the third cleaning chamber 5). The glass sheet G is carried into the third cleaning chamber 5 through the opening 19 by the transport roller 2.

[0042] The fourth cleaning chamber 6 is provided with conveying rollers 2 and a fourth shower nozzle 20 that supplies the alkaline cleaning solution D2 to the glass sheet G. The fourth cleaning chamber 6 is connected to a fourth recovery tank 22 by a pipe 21, and the alkaline cleaning solution D2 that has accumulated at the bottom of the fourth cleaning chamber 6 is recovered in the fourth recovery tank 22 through the pipe 21. The third cleaning chamber 5 and the fourth cleaning chamber 6 are connected to each other by an opening 23 provided in a wall portion on the downstream side of the third cleaning chamber 5 (a wall portion on the upstream side of the fourth cleaning chamber 6). The glass sheet G is carried into the fourth cleaning chamber 6 through the opening 23 by the conveying rollers 2.

[0043] The fifth cleaning chamber 7 is provided with a transport roller 2 and a fifth shower nozzle 24 that supplies rinsing liquid W to the glass sheet G. The fifth cleaning chamber 7 is connected to a fifth recovery tank 26 by a pipe 25, so that the rinsing liquid W accumulated at the bottom of the fifth cleaning chamber 7 is recovered in the fifth recovery tank 26 through the pipe 25. The fourth cleaning chamber 6 and the fifth cleaning chamber 7 are connected to each other by an opening 27 provided in the downstream wall of the fourth cleaning chamber 6 (the upstream wall of the fifth cleaning chamber 7). The glass sheet G is transported into the fifth cleaning chamber 7 through the opening 27 by the transport roller 2. The fifth cleaning chamber 7 is connected to an area where a process subsequent to the cleaning process is performed by an opening 28 provided in the downstream wall of the fifth cleaning chamber 7. The glass sheet G in the fifth cleaning chamber 7 is transported to the subsequent process through the opening 28 by the transport roller 2. The post-processing includes, for example, an inspection process for inspecting the glass sheet G for defects (including stains), and a packaging process for packaging the glass sheet G on a pallet.

[0044] Each shower nozzle 8, 12, 16, 20, 24 includes an upper nozzle 8a, 12a, 16a, 20a, 24a that is disposed above the first main surface (upper surface) Ga of the glass sheet G and supplies the predetermined liquids W, D1, D2 to the first main surface Ga, and a lower nozzle 8b, 12b, 16b, 20b, 24b that is disposed below the second main surface (lower surface) Gb of the glass sheet G and supplies the predetermined liquids W, D1, D2 to the second main surface Gb. The liquid supply device that supplies the predetermined liquids W, D1, D2 is not limited to a shower nozzle and may be, for example, a spray nozzle.

[0045] In this embodiment, cleaners 29, 31 that scrub and clean the glass sheet G are provided in the second cleaning chamber 4 and the fourth cleaning chamber 6, respectively. Each cleaner 29, 31 includes an upper cleaner 29 a, 31 a that scrubs and cleans the first main surface Ga, and a lower cleaner 29 b, 31 b that scrubs and cleans the second main surface Gb. Examples of the cleaners 29, 31 include a disk and a brush.

[0046] The rinse liquid W recovered in the first recovery tank 10 is supplied to the first shower nozzle 8 in the first cleaning chamber 3 via a pump 32 and piping 33. The acidic cleaning liquid D1 recovered in the second recovery tank 14 is supplied to the second shower nozzle 12 in the second cleaning chamber 4 via a pump 34 and piping 35. The rinse liquid W recovered in the third recovery tank 18 is supplied to the third shower nozzle 16 in the third cleaning chamber 5 via a pump 36 and piping 37. The alkaline cleaning liquid D2 recovered in the fourth recovery tank 22 is supplied to the fourth shower nozzle 20 in the fourth cleaning chamber 6 via a pump 38 and piping 39. The rinse liquid W recovered in the fifth recovery tank 26 is supplied to the fifth shower nozzle 24 in the fifth cleaning chamber 7 via a pump 40 and piping 41. In other words, the predetermined liquids W, D1, and D2 are circulated and reused in each of the cleaning chambers 3 to 7.

[0047] In this embodiment, among the first recovery tank 10, the third recovery tank 18, and the fifth recovery tank 26, the tank located downstream has a higher maximum storage level (liquid surface) of the rinse liquid W than the tank located upstream. That is, the fifth recovery tank 26 has the highest maximum storage level, and the first recovery tank 10 has the lowest maximum storage level. The first recovery tank 10 and the third recovery tank 18 are connected by a first communication passage 42 that slopes downward toward the first recovery tank 10. The third recovery tank 18 and the fifth recovery tank 26 are connected by a second communication passage 43 that slopes downward toward the third recovery tank 18. When the rinse liquid W stored in the fifth recovery tank 26 exceeds the maximum storage level, the rinse liquid W overflows from the fifth recovery tank 26 and is supplied to the third recovery tank 18 through the second communication passage 43 (the flow of rinse liquid W shown by arrow B). Furthermore, when the rinse liquid W stored in the third collection tank 18 exceeds the maximum storage level, the rinse liquid W overflows from the third collection tank 18 and is supplied to the first collection tank 10 through the first communication passage 42 (the flow of rinse liquid W indicated by arrow C). The method of supplying the rinse liquid W from the downstream collection tank to the upstream collection tank is not limited to the method using overflow. For example, a pump or the like may be used to supply the rinse liquid W from the downstream collection tank to the upstream collection tank.

[0048] The rinse liquid W stored in the fifth recovery tank 26 has a low reuse rate and a high degree of cleanliness. Therefore, the fifth recovery tank 26 is configured to be replenished with pure water as the rinse liquid W by a rinse liquid replenishment device 44. The replenishment amount and replenishment timing of the rinse liquid replenishment device 44 are pre-programmed so that the pure water is automatically replenished. Note that the rinse liquid replenishment device 44 may, for example, detect the liquid level of the rinse liquid W stored in the fifth recovery tank 26 with a sensor and determine the replenishment amount and replenishment timing of the pure water based on the detection result. Alternatively, the rinse liquid replenishment device 44 may continuously supply a constant amount of pure water.

[0049] The rinse liquid W stored in the first recovery tank 10 has a high reuse rate and a low cleanliness level. Therefore, the rinse liquid W that overflows from the first recovery tank 10 is disposed of (the flow of the rinse liquid W indicated by the arrow D). The rinse liquid W does not contain a surfactant and is mainly composed of water, so it is easy to dispose of.

[0050] An alkaline component or an acid component (pH adjuster) is added to the rinse liquid W stored in the third collection tank 18 by an addition device 45. The amount and timing of addition of the alkaline component or acid component are preprogrammed in the addition device 45, so that these components are added automatically. Note that the addition device 45 may, for example, measure the pH of the rinse liquid W stored in the third collection tank 18 and determine the amount and timing of addition of the alkaline component or acid component based on the measurement results. Specifically, the alkaline component or acid component may be added when the pH of the rinse liquid is greater than 4 and less than 9.

[0051] In this embodiment, the rinse liquid W overflowing from the third recovery tank 18 is supplied to the first recovery tank 10. Therefore, when an alkaline component or an acid component is added to the rinse liquid W stored in the third recovery tank 18, the rinse liquid W to which the alkaline component or the acid component has been added is also supplied to the first recovery tank 10. Therefore, the rinse liquid W to which the alkaline component or the acid component has been added is supplied to the first cleaning chamber 3 through the first recovery tank 10, and the rinse liquid W to which the alkaline component or the acid component has been added is supplied to the third cleaning chamber 5 through the third recovery tank 18.

[0052] Next, a method for manufacturing a glass article using the glass article manufacturing apparatus configured as above will be described.

[0053] The method for manufacturing a glass article according to the first embodiment of the present invention includes a cleaning step.

[0054] As shown in FIGS. 1 and 2 , the cleaning process includes a first rinsing process S1 in which the glass sheet G is cleaned with a rinsing liquid W in a first cleaning chamber 3, an acid cleaning process S2 in which the glass sheet G is cleaned with an acidic cleaning liquid D1 in a second cleaning chamber 4, a second rinsing process S3 in which the glass sheet G is cleaned with the rinsing liquid W in a third cleaning chamber 5, an alkaline cleaning process S4 in which the glass sheet G is cleaned with an alkaline cleaning liquid D2 in a fourth cleaning chamber 6, and a third rinsing process S5 in which the glass sheet G is cleaned with the rinsing liquid W in a fifth cleaning chamber 7.

[0055] The cleaning process further includes a rinse liquid recovery process in which the rinse liquid W used in the first rinsing process S1, the second rinsing process S3, and the third rinsing process S5 is recovered in the recovery tanks 10, 18, and 26. The first rinsing process S1, the second rinsing process S3, and the third rinsing process S5 include a reuse process in which the rinse liquid W recovered in each recovery tank 10, 18, and 26 in the rinse liquid recovery process is reused. In detail, the rinse liquid W recovered in the first recovery tank 10 is reused in the first cleaning chamber 3, the rinse liquid W recovered in the third recovery tank 18 is reused in the third cleaning chamber 5, and the rinse liquid W recovered in the fifth recovery tank 26 is reused in the fifth cleaning chamber 7. By recovering and reusing the rinse liquid W in this manner, the amount of rinse liquid W used can be significantly reduced.

[0056] In this embodiment, a portion of the rinsing liquid W recovered in the fifth recovery tank 26 is supplied to the third recovery tank 18 through the second communication passage 43. Similarly, a portion of the rinsing liquid W recovered in the third recovery tank 18 is supplied to the first recovery tank 10 through the first communication passage 42. Therefore, the cleanliness of the rinsing liquid W increases in the order of the first recovery tank 10, the third recovery tank 18, and the fifth recovery tank 26. In other words, as the glass sheet G is transported downstream and the cleaning process progresses, the cleanliness of the rinsing liquid W used increases. Note that the rinsing liquid W recovered in each of the recovery tanks 10, 18, and 26 is preferably reused after removing foreign matter using a filter or the like.

[0057] The cleaning process further includes an acidic cleaning solution recovery process in which the acidic cleaning solution D1 used in the acidic cleaning process S2 is recovered in the second recovery tank 14, and an alkaline cleaning solution recovery process in which the alkaline cleaning solution D2 used in the alkaline cleaning process S4 is recovered in the third recovery tank 18. The acidic cleaning process S2 includes a reuse process in which the acidic cleaning solution D1 recovered in the second recovery tank 14 in the acidic cleaning solution recovery process is reused in the second cleaning chamber 4. The alkaline cleaning process S4 includes a reuse process in which the alkaline cleaning solution D2 recovered in the fourth recovery tank 22 in the alkaline cleaning solution recovery process is reused in the fourth cleaning chamber 6. By recovering and reusing the acidic cleaning solution D1 and the alkaline cleaning solution D2 in this way, the amounts of these solutions D1 and D2 used can be significantly reduced.

[0058] The acid cleaning step S2 is performed, for example, to remove calcium stains adhering to the surface of the glass sheet G using an acid component. In the acid cleaning step S2, an aqueous solution containing, for example, a hydroxy acid can be used as the acid cleaning solution D1. Hydroxy acids are carboxylic acids with a hydroxyl group structure, which are highly water-soluble and can prevent separation from water over long periods of use. Examples of hydroxy acids include organic acids such as glycolic acid, lactic acid, tartaric acid, citric acid, malic acid, and salicylic acid. The pH of the acid cleaning solution D1 is preferably 1 or more and 3 or less. Taking into account equipment wear and ease of disposal of cleaning water, the pH of the acid cleaning solution D1 is more preferably 1.5 or more. Taking into account cleaning performance, the pH of the acid cleaning solution D1 is more preferably 2.8 or less. Furthermore, the acid cleaning solution D1 preferably contains a surfactant for cleaning and removing organic stains on the glass sheet G. The surfactant covers the stain components, thereby preventing the removed stains from re-adhering to the glass sheet G.

[0059] The alkaline cleaning step S4 is performed, for example, to remove organic contaminants adhering to the surface of the glass sheet G that could not be removed in the acid cleaning step using an alkaline component. In the alkaline cleaning step S4, an aqueous solution containing at least one of sodium hydroxide and potassium hydroxide can be used as the alkaline cleaning solution D2. The pH of the alkaline cleaning solution D2 is preferably 10 or more and 13 or less. Taking into account ease of disposal of the cleaning water, the pH of the alkaline cleaning solution D2 is more preferably 12 or less, and taking into account cleaning properties, the pH of the alkaline cleaning solution D2 is more preferably 10.5 or more. Furthermore, the alkaline cleaning solution D2 preferably contains a surfactant for cleaning and removing organic contaminants from the glass sheet G. The surfactant covers the contaminant components, thereby preventing the removed contaminants from re-adhering to the glass sheet G.

[0060] By using the acid cleaning step S2 and the alkali cleaning step S4 in combination in this way, it is possible to effectively remove various types of dirt adhering to the glass sheet G. In particular, when the alkali cleaning step S4 is performed after the acid cleaning step S2, the effect of removing dirt adhering to the glass sheet G is enhanced. Note that the alkali cleaning step S4 and the third rinsing step S5 may be omitted.

[0061] The first rinsing step S1 is performed, for example, for the purpose of pre-washing the glass sheet G with a rinsing liquid W. The second rinsing step S3 is performed, for example, for the purpose of removing the acidic cleaning liquid D1 adhering to the glass sheet G with the rinsing liquid W. The third rinsing step S5 is performed, for example, for the purpose of removing the alkaline cleaning liquid D2 adhering to the glass sheet G with the rinsing liquid W. The rinsing liquid W contains water (pure water) as a main component and does not contain a surfactant.

[0062] Here, bacteria are likely to grow in the first cleaning chamber 3, which performs the first rinsing step S1, and the third cleaning chamber 5, which performs the second rinsing step S3. The reason for the bacteria growth is thought to be as follows: The first cleaning chamber 3 is adjacent to the upstream side of the second cleaning chamber 4, which performs the acid cleaning step S2, and the third cleaning chamber 5 is adjacent to the downstream side of the second cleaning chamber 4, which performs the acid cleaning step S2. Therefore, the acid cleaning solution D1 is likely to be mixed into the rinsing solution W used in the first cleaning chamber 3 or the third cleaning chamber 5 via the glass sheet G or the like. When a small amount of the acid cleaning solution D1 is mixed into the rinsing solution W in this way and the pH falls within the range of more than 4 and less than 9, bacteria are likely to grow. In particular, when the acid cleaning solution D1 contains an organic acid (organic component), bacteria are likely to grow and increase.

[0063] Therefore, the present manufacturing method further includes an adjustment step of adding an alkaline component or an acid component to the rinse W used in the first rinse step S1 and the second rinse step S3 to adjust the pH of the rinse W.

[0064] 1 , in the adjustment step, an alkaline component or an acid component is added by an addition device 45 to the rinse liquid W stored in the third recovery tank 18 to adjust the pH of the rinse liquid W stored in the third recovery tank 18 to 4 or less or 9 or more. As a result, the rinse liquid W whose pH has been adjusted to 4 or less or 9 or more is supplied from the third recovery tank 18 to the third shower nozzle 16. As a result, the rinse liquid W whose pH has been adjusted is sprayed from the third shower nozzle 16 into the third cleaning chamber 5.

[0065] Furthermore, since the pH-adjusted rinse liquid W is supplied from the third recovery tank 18 to the first recovery tank 10, the pH-adjusted rinse liquid W is also stored in the first recovery tank 10. Therefore, the pH-adjusted rinse liquid W is supplied from the first recovery tank 10 to the first shower nozzle 8. As a result, the pH-adjusted rinse liquid W is sprayed from the first shower nozzle 8 into the first cleaning chamber 3.

[0066] In this way, a rinse liquid W with a pH adjusted to 4 or less or 9 or more is used in the first cleaning chamber 3 and the third cleaning chamber 54, thereby suppressing the generation of bacteria in the first cleaning chamber 3 and the third cleaning chamber 54.

[0067] In the preparation step, an alkaline aqueous solution can be used as the alkaline component. Examples of the alkaline aqueous solution include an aqueous sodium hydroxide solution and an aqueous potassium hydroxide solution. Examples of the acid component can include inorganic acids such as hydrochloric acid, sulfuric acid, and nitric acid.

[0068] When an alkaline component is added in the adjustment step, the pH of the rinse liquid W to which the alkaline component has been added is preferably 9 or higher, and more preferably 10 or higher. The pH of the rinse liquid W to which the alkaline component has been added is preferably 12 or lower, and more preferably 11 or lower.

[0069] When an acid component is added in the adjustment step, the pH of the rinse liquid W to which the acid component has been added is preferably 4 or less, more preferably 3 or less, and even more preferably 2 or less. In addition, the pH of the rinse liquid W to which the acid component has been added is preferably 1.5 or more.

[0070] The pH of the rinse liquid W to which an alkaline component is added is preferably lower than that of the alkaline cleaning liquid D2, and the pH of the rinse liquid W to which an acid component is added is preferably higher than that of the acidic cleaning liquid D1. That is, it is preferable that the pH of the acidic cleaning liquid D1 < the pH of the rinse liquid W < the pH of the alkaline cleaning liquid D2.

[0071] However, in the adjustment step, from the viewpoint of suppressing wear on the equipment, it is preferable to add an alkaline component so that the pH of the rinse liquid W stored in the first recovery tank 10 and the third recovery tank 18 becomes 9 or higher.

[0072] (Second embodiment) As shown in Figure 3, the glass article manufacturing apparatus and manufacturing method according to the second embodiment differ from the first embodiment in that the rinsing liquid W recovered in each recovery tank 10, 18, 26 is not supplied to another recovery tank.

[0073] Specifically, in this embodiment, the collection tanks 10, 18, and 26 that collect the rinse liquid W are independent of each other, and the rinse liquid W is not transferred between the collection tanks 10, 18, and 26. Therefore, an alkaline component or an acid component (pH adjuster) is added individually to the rinse liquid W stored in the first collection tank 10 by the first addition device 45a, and an alkaline component or an acid component is added individually to the rinse liquid W stored in the third collection tank 18 by the second addition device 45b. As a result, as in the first embodiment, the rinse liquid W stored in the first collection tank 10 to which the alkaline component or the acid component has been added is supplied to the first cleaning chamber 3, and the rinse liquid W stored in the third collection tank 18 to which the alkaline component or the acid component has been added is supplied to the third cleaning chamber 5.

[0074] The present invention is not limited to the configuration of the above-described embodiment, nor is it limited to the above-described effects. The present invention can be modified in various ways without departing from the spirit of the present invention.

[0075] In the first embodiment described above, a case where a rinse liquid W containing an alkaline or acid component is supplied to the first cleaning chamber 3 and the third cleaning chamber 5 adjacent to the second cleaning chamber 4 where the acid cleaning step S2 is performed (a case where a rinse liquid W containing an alkaline or acid component is not supplied to the fifth cleaning chamber 7) has been described. However, this is not limiting. If there is a risk of bacteria generation in the fifth cleaning chamber 7 adjacent to the downstream side of the fourth cleaning chamber 6 where the alkaline cleaning step S4 is performed, a rinse liquid W containing an alkaline or acid component may be supplied to the fifth cleaning chamber 7. In the first embodiment, when an alkaline or acid component is added to the rinse liquid W stored in the fifth recovery tank 26 to supply the rinse liquid W containing an alkaline or acid component to the fifth cleaning chamber 7, the rinse liquid W containing an alkaline or acid component is supplied to the third recovery tank 18 from the fifth recovery tank 26, so that the alkaline or acid component does not need to be directly added to the rinse liquid W in the third recovery tank 18.

[0076] In the above first and second embodiments, the case where the rinse liquid W to which an alkaline component or an acid component has been added is supplied from the first recovery tank 10 to the first cleaning chamber 3, and the rinse liquid W to which an alkaline component or an acid component has been added is supplied from the third recovery tank 18 to the third cleaning chamber 5 has been described, but this is not limiting. For example, the first shower nozzle 8 and the third shower nozzle 16 may each be connected to the third recovery tank 18 by piping or the like, and the rinse liquid W to which an alkaline component or an acid component has been added may be supplied from the third recovery tank 18 to the first cleaning chamber 3 and the third cleaning chamber 5, respectively. In this case, the rinse liquid W having the same reuse rate is supplied to the first cleaning chamber 3 and the third cleaning chamber 5.

[0077] In the case where the rinse liquid W to which an alkaline component or an acid component is added is supplied from the third recovery tank 18 to each of the first cleaning chamber 3 and the third cleaning chamber 5, the rinse liquid W used in the first cleaning chamber 3 may be collected in the third recovery tank 18. In this case, the third recovery tank 18 also serves as the first recovery tank 10. Alternatively, in the case where the rinse liquid W to which an alkaline component or an acid component is added is supplied from the third recovery tank 18 to each of the first cleaning chamber 3 and the third cleaning chamber 5, the rinse liquid W used in the first cleaning chamber 3 may be discarded without being reused.

[0078] In the above first and second embodiments, the case where the rinse liquid W is recovered and reused has been described, but the rinse liquid W does not have to be reused. That is, unused rinse liquid W may be supplied to at least one of the first cleaning chamber 3, the third cleaning chamber 5, and the fifth cleaning chamber 7. In this case, it is preferable to add an alkaline component or an acid component to the unused rinse liquid W before use.

[0079] In the first and second embodiments described above, the rinsing liquid W to which an alkaline component or an acid component is added is supplied to both the first cleaning chamber 3 in which the first rinsing step S1 is performed and the third cleaning chamber 5 in which the second rinsing step S3 is performed. However, this is not limiting. For example, the rinsing liquid W to which an alkaline component or an acid component is added may be supplied to only one of the first cleaning chamber 3 and the third cleaning chamber 5.

[0080] In the first and second embodiments described above, a glass plate is exemplified as the glass article, but the glass article is not limited thereto. The glass article may be, for example, a glass tube, a glass rod, an optical glass component, a glass block, or the like.

[0081] REFERENCE SIGNS LIST 1 Cleaning device 2 Conveying rollers 3, 4, 5, 6, 7 Cleaning chamber 8, 12, 16, 20, 24 Shower nozzle 10, 14, 18, 22, 26 Recovery tank 29, 31 Cleaning machine 44 Rinse liquid replenishing device 45 Addition device W Rinse liquid D1 Acidic cleaning liquid D2 Alkaline cleaning liquid G Glass plate S1 First rinsing cleaning process S2 Acid cleaning process S3 Second rinsing cleaning process S4 Alkaline cleaning process S5 Third rinsing cleaning process

Claims

1. A method for manufacturing a glass article, comprising: an acid cleaning step of cleaning the glass article with an acid cleaning solution; a rinsing step of cleaning the glass article with a rinsing solution in at least one of an upstream area and a downstream area adjacent to an area where the acid cleaning step is carried out; and an adjustment step of adjusting the pH of the rinsing solution used in the rinsing step, wherein the adjustment step adjusts the pH of the rinsing solution to 4 or less, or 9 or more.

2. The method for manufacturing a glass article according to claim 1, wherein the rinsing step is carried out in the downstream area, and the rinsing liquid used in the downstream area has an adjusted pH.

3. A method for manufacturing a glass article as described in claim 1, wherein the rinsing process is carried out in both the upstream area and the downstream area, and the rinsing liquid having an adjusted pH is used in both the upstream area and the downstream area.

4. A method for manufacturing a glass article as described in claim 2 or 3, further comprising a recovery process for recovering the rinsing liquid used in the rinsing process, the rinsing process including a reuse process for reusing the rinsing liquid recovered in the recovery process, and the adjustment process for adjusting the pH of the rinsing liquid recovered in the recovery process.

5. A method for manufacturing a glass article as described in claim 4, wherein the rinsing process is performed in both the upstream area and the downstream area, the recovery process recovers the rinsing liquid used in the downstream area, the adjustment process adjusts the pH of the rinsing liquid recovered from the downstream area in the recovery process, and the reuse process reuses the rinsing liquid recovered from the downstream area in the recovery process and whose pH has been adjusted, in the upstream area and the downstream area.

6. A method for manufacturing a glass article as described in claim 5, wherein in the recovery process, the rinsing liquid used in the upstream area is recovered in a first recovery tank, and the rinsing liquid used in the downstream area is recovered in a second recovery tank; in the adjustment process, the pH of the rinsing liquid recovered in the second recovery tank is adjusted; and in the reuse process, the rinsing liquid with the pH adjusted is supplied from the second recovery tank to the first recovery tank, and the rinsing liquid with the pH adjusted is supplied from the first recovery tank to the upstream area, and the rinsing liquid with the pH adjusted is supplied from the second recovery tank to the downstream area.

7. The method for manufacturing a glass article according to any one of claims 1 to 3, further comprising an alkaline cleaning step of cleaning the glass article with an alkaline cleaning solution.

8. A method for manufacturing a glass article according to any one of claims 1 to 3, wherein the pH of the rinsing liquid whose pH has been adjusted is 9 or higher.

9. The method for manufacturing a glass article according to any one of claims 1 to 3, wherein the conditioning step is carried out using an alkaline aqueous solution.

10. The method for manufacturing a glass article according to any one of claims 1 to 3, wherein the acidic cleaning solution contains an organic acid.

11. The method for manufacturing a glass article according to any one of claims 1 to 3, wherein the rinsing liquid does not contain a surfactant.

12. An apparatus for manufacturing glass articles, comprising: an acid cleaning area for cleaning the glass articles with an acid cleaning solution; a rinsing area provided in at least one of an upstream area and a downstream area adjacent to the acid cleaning area for cleaning the glass articles with a rinsing solution; and an addition device for adding a component for adjusting the pH to the rinsing solution used in the rinsing area.

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