Classifications

• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
  • C03B27/00—Tempering or quenching glass products
  • C03B27/04—Tempering or quenching glass products using gas
  • C03B27/0404—Nozzles, blow heads, blowing units or their arrangements, specially adapted for flat or bent glass sheets
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
  • C03B27/00—Tempering or quenching glass products
  • C03B27/04—Tempering or quenching glass products using gas
  • C03B27/044—Tempering or quenching glass products using gas for flat or bent glass sheets being in a horizontal position

Definitions

• Tempering takes place normally in about 1200 long tempering section, through which a thin glass, thickness generally 2,8 - 4,0 mm, is driven by relatively fast speed, at about 600 rnm s, during which time the tempering takes place.
• Final cooling takes place only in cooling section located after tempering section.
• the method is advantageous, since only relatively short length requires high cooling power. In majority of cases glasses are loaded at the length of about 3 — 5 metres and if tempering pressure should be applied to such a length, the needed tempering power would be even up to 3 - 4 times higher, that in tempering section, the length of which is about 1200 mm, (not considering the power needed for the cooling section). This method thus allows reduction of peak power during tempering.
• cooling section which is generally 200 — 400 mm longer than glass.
• cooling is it not sensible to use as high cooling power as during tempering and, on the other hand, when cooling section area is large, also the required air flow is high so tempering blower is not well suited for final cooling. Additionally high pressure tempering blower specific pressure curve is unsuitable and energy wasteful if it is used for low pressure after cooling.
• tempering and after cooling sections both require their own blowers, which increase expenses.
• tempering blower is used only during tempering and there is no time enough to stop the blower in between the tempering phases, all the energy it uses in between tempering phases is a waste. Even though the energy it draws during these periods can be reduced in various ways, still the waste is remarkable.
• One way to reduce tempering peak power in this combined tempering and cooling method is to divide the section into two parts.
• the first part is now tempering section, into which two blowers blow in series so that sufficient tempering pressure for thin glass is reached.
• This method is described in publication FI 100525 B. Also this involves use of earlier mentioned compromise nozzle arrangements. It can be noted, that method of the publication FI 100525 B leads into the situation, in which the leading end of the glass is driven through high pressure section and it is totally tempered and cooled into certain temperature and now gate 10 is opened in the situation, when the trailing end of the glass has not yet cooled into the temperature of the leading end of the glass. Uneven cooling of the glass can cause the glass to break.
• Characteristic for the method according to the invention is that the air produced by tempering section blower/blowers can be directed during tempering wholly into tempering section or part of the air can be directed into after cooling section. During after cooling the air from same blower/blowers is, instead, directed at least mainly into after cooling section.
• Tempering of thicker glasses becomes also easier, as open area of nozzles is larger and thus reaching low tempering effects becomes easier.
• selection of blower(s) and length of glass loading even the whole blower for after cooling section may be eliminated.
• Division of air in between tempering section and after cooling section can be made either after the discharge opening of blower/blowers or by a device located either in tempering section or in after cooling section.
• Blowers Bl and B2 can be typically medium pressure blowers.
• air pressure of tempering section is produced by two of this kind of blowers Bl and B2, connected in series during tempering, high enough tempering pressure even for thin glasses, such as 2,8 mm, can be reached without increasing the connected power.
• tempering section could even be made longer, for example by 300 mm, which would typically increase cooling time 0,5 seconds.
• tempering machine produces blower air in some other section, for example suction removes over pressure from tempering section, it is useful to lead this air into after cooling section to cool glass during tempering.
• the glass has been without final cooling only a short period of time and it has no time to lose it degree of tempering if and when it has been cooled just below necessary tempering temperature.
• the gate G can totally close entering of air into after cooling section or gate Gl can lead all air of blower Bl into blower B2 in order to reach necessary tempering pressure.
• blower Bl has more extra air, which does not need to be conducted into blower B2 in order to reach sufficient tempering pressure.
• the gate Gl should now be opened just enough so that necessary tempering pressure is achieved and all surplus air is conducted into the cooling section, (gate opening positions Gl', Gl", Gl'" etc.) In this way all air production of blowers is utilized for tempering and cooling of glass and nothing would be wasted, which would be the case with vane- and throttling control.
• FIGS. 1 — 5 are schematic drawings of tempering section seen from above. The furnace part and unloading section are excluded.
• blowers B, Bl and B2 blow into lower and upper nozzles in tempering and cooling sections. However, it is possible to use the invention with one or more blowers.
• the figures have following markings;
• - Bl is the feed blower of tempering section but it may also be called blower for cooling section
• - G is division device, which divides air in between tempering-and cooling sections. It is located in upper and lower nozzle blocks and it can be alternatively located in cooling section, too.
• - Ga is similar device as G, but it divides air directly from blower B in between tempering and cooling sections.
• - Gl is division plate, which divides the air production of blower Bl either into the blower B2 or into the cooling section CS or shares the air in between them as described.
• Fig. 1 describes the alternative, in which only one blower B is used and the air produced by it is conducted into tempering section TS and/or cooling section CS by adjusting division device G or alternative device Ga to the wanted position.
• This arrangement is suitable particularly for short loadings and 4 mm and thicker glasses. If the device Ga is used, the air ducts of tempering section and cooling section must be totally separated during tempering. Instead a separate air channel from Ga into cooling section CS is needed.
• Fig. 2 describes an arrangement to temper thin glasses, when high pressures are needed and often 2 blowers are used in series.
• Channel C is attached on to the intake opening of blower B2 and device Gl divides at least majority of the air from the blower Bl in to the blower B2.
• Gate G closes the connection from tempering section into the cooling section so that the tempering section has high pressure and cooling section low pressure or is without pressure. There is a free access of the air from nozzle blocks into the nozzles in both sections.
• the pressure produced by the hlowers can be controlled primarily by the position of the gate Gl but also by other known methods.
• Figure 3 describes an arrangement which is typical for tempering of thin glass during the beginning of the cooling stage, when both blowers still run.
• the gate G has opened access into the cooling section, but prevents the air access into the tempering section nozzles, (darkened).
• the gate Gl now conducts the air from blower Bl directly into the cooling section CS and channel C has been opened up so that the blower B2 has free suction from open air and also it blows all of its air into the cooling section. Cooling continues optimally so, that both blowers or just one of them is used at such a speed, which, with minimum power consumption, cools the glass to a low enough unloading temperature.
• the air volume required by cooling section can be so high, that also the air of blower B2 is needed for glass cooling. This is possible, if blowers Bl and B2, when working independently, can run at the same point of blower curve.
• Figure 4 shows an arrangement, in which tempering of thin glass is in progress and in which a part of the air from blower Bl is conducted into the air channels into the nozzle blocks according to the figure 6.
• Leading of such an air for example, under the rollers and possibly similarly into the upper nozzle blocks, into the low pressure air channel CLP and through the openings onto the feet of the high pressure nozzles would improve ihe ejector effect, which is caused by high pressure, fast moving air jets JHP.
• In the tempering section particularly important is increase of the cooling power. Partially this "secondary air" ensures that ejector air is in sufficient quantity in every place so that the cooling effect is similar on the whole width of the glass.
• Figure 5 shows a method in which the air received from tempering section by blower B3 can be lead into the cooling section nozzles, figure 6, through the channels CHP. In this way the cooling effect of this air can be utilized during the tempering and initial stages of cooling.
• the air from blower B3 or other similar air can be lead through low pressure channels CLP of picture 6 into the foot of the nozzles.
• the secondary air should produce more ejector air to the space between the high pressure nozzles and rollers, which would further secure transfer of possible broken glasses away from between the rollers and the nozzles.
• optimal tempering nozzles could be better used also in cooling section.
• typical 1,2 metres long tempering sections, through which the glass is driven the glass normally has no time to break so that this arrangement in tempering section is not so important.

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• Chemical & Material Sciences (AREA)
• Physics & Mathematics (AREA)
• Thermal Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Organic Chemistry (AREA)
• Re-Forming, After-Treatment, Cutting And Transporting Of Glass Products (AREA)

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ID=33522613

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• 2004
  • 2004-06-24 WO PCT/FI2004/000383 patent/WO2004113241A1/en active Application Filing
  • 2004-06-24 EP EP04742126A patent/EP1651579A1/de not_active Withdrawn

Non-Patent Citations (1)

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