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WO2004024642A1 - Convective method of heating glass sheets using compressed air in conjunction with heated oven air - Google Patents

Convective method of heating glass sheets using compressed air in conjunction with heated oven air Download PDF

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Publication number
WO2004024642A1
WO2004024642A1 PCT/FI2003/000673 FI0300673W WO2004024642A1 WO 2004024642 A1 WO2004024642 A1 WO 2004024642A1 FI 0300673 W FI0300673 W FI 0300673W WO 2004024642 A1 WO2004024642 A1 WO 2004024642A1
Authority
WO
WIPO (PCT)
Prior art keywords
air
oven
compressed air
pipes
nozzle
Prior art date
Application number
PCT/FI2003/000673
Other languages
French (fr)
Inventor
Clifford V. Matukonis
Anthony J. Narducci
Original Assignee
Tamglass Ltd. Oy
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Tamglass Ltd. Oy filed Critical Tamglass Ltd. Oy
Priority to AU2003262598A priority Critical patent/AU2003262598A1/en
Priority to EP03795038A priority patent/EP1551775A1/en
Publication of WO2004024642A1 publication Critical patent/WO2004024642A1/en

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B29/00—Reheating glass products for softening or fusing their surfaces; Fire-polishing; Fusing of margins
    • C03B29/04—Reheating glass products for softening or fusing their surfaces; Fire-polishing; Fusing of margins in a continuous way
    • C03B29/06—Reheating glass products for softening or fusing their surfaces; Fire-polishing; Fusing of margins in a continuous way with horizontal displacement of the products
    • C03B29/08—Glass sheets

Definitions

  • the present invention relates to a semi-connective forced air system and method for heating glass sheets for subsequent processing. More particularly, the system and method of the present invention are used for heating low emissivity coated glass sheets (low "e" glass) before tempering and then tempering the glass sheets.
  • the invention includes new and improved nozzles for delivering a hot mixture of compressed air and heated oven air to a sheet of glass inside an oven.
  • the glass sheet If the air is kept on too long, the glass sheet exits the oven too cold and breaks.
  • the glass sheet needs to attain the final process temperature of about 634 °C via infrared radiation. This is the slowest form of heat transfer for low "e” glass sheets and it adds extra time to the heating cycle.
  • Fig. 1 is a view in side elevation of a compressed air assembly pipe with nozzles inserted therein and with hangers adapted for hanging the pipe from the ceiling of an oven.
  • Fig. 2 is a view in bottom plan of Fig. 1.
  • Fig. 3 is a view in elevation of a compressed air infeed pipe of Fig. 1.
  • Fig. 4 is an enlarged view in detail of the area marked 4 in Fig. 3.
  • Fig. 5 is an enlarged view in side elevation of a portion of the pipe and nozzles shown in Fig. 1.
  • Fig. 5a is an end view of Fig. 5 looking from the left of Fig. 5.
  • Fig. 5b is a view in top plan of one of the nozzles of Fig. 5.
  • Fig. 6 is a view in bottom plan of Fig. 5.
  • Fig. 7 is a view in rear elevation of a nozzle of Fig. 5.
  • Fig. 8 is a view in front elevation of the nozzle of Fig. 7.
  • Fig. 9 is a view in side elevation of the rollers, pipes, nozzles, clamps, hangers, and compressed air infeed pipes inside an oven.
  • Fig. 10 is a view in top plan of the pipes and nozzles in the oven.
  • Fig. 11 is a view showing the layout of the aspiration system including air tank, compressed air infeed pipes, distribution pipes and nozzles.
  • Fig. 12a shows a view in side elevation of a pipe flange.
  • Fig. 12b shows a view in elevation of a face of the flange of Fig. 12a looking from the left of Fig. 12a.
  • Fig. 12c shows a view in elevation of the other face of the flange looking from the right of Fig. 12a.
  • Fig. 7 shows a view in rear elevation of a nozzle 21
  • Fig. 8 shows a view in front elevation of the nozzle 21.
  • Compressed air goes into nozzle 21 through hole 23 and oven air is pulled into the nozzle through upper port 25 and the compressed and the oven air are mixed in mixing chamber 26 in the lower park of the nozzle 21 to form a hot air mix.
  • the mix of compressed air and oven air is discharged through lower port 27 onto glass sheets S to heat them for further procedures, like tempering.
  • Hole 23 is an angled hole that has been optimized at 30° for ease of machining, but it can be other angles.
  • the hole diameter is .080 mm, so particles which form inside the compressed air delivery system can blow through these holes.
  • the hole diameter can be changed if necessary or desired.
  • Upper port 25 is flared at inside flare 29 to allow for easier suction of oven air into this nozzle 21.
  • Lower port 27 is flared inwardly on the outside surface flare 30 of the nozzle 21.
  • Fig. 5 and the bottom view of Fig. 6 show the air amplification nozzles 21 pressed through a manifold or pipe 31 which delivers the compressed air to the nozzles 21.
  • Fig. 5b shows the orientation of the hole 23 in nozzle 21 to the manifold pipe 31.
  • the hole 23 is facing toward the opposite wall so that no particles can blow directly into this hole
  • Fig. 5 shows a side elevation view of the manifold pipe 31 with the nozzles 21 pressed through it.
  • Fig. 6 shows a bottom view of Fig. 5 of the manifold pipe 31 with the nozzles 21.
  • the number of nozzles 21 per manifold pipe 31 can vary to accommodate the length of the manifold pipe 31. Typically, the nozzles 21 are on 30 cm centers.
  • Figs. 1 and 2 show an assembly of the compressed air system with the compressed air being fed into the center of pipe 35 between sub-pipes 35a and 35b through the compressed air infeed pipe 33.
  • the compressed air comes into the oven 43 through a compressed air infeed distribution pipe 33 and pipes 35a, 35b and by the time it passes through the oven 43 and reaches the nozzle 21 it is at about 426°C, whereupon it is mixed with the hotter oven air which is at about 676°C to 704°C into a mix that is delivered by the nozzles 21 to the glass sheet S at about 690°C.

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

Abstract

A semi-convective forced air system for heating glass sheets, comprises a heating chamber in an oven, a longitudinal conveyor extending through the heating chamber, a compressed air source, a plurality oflongitudinally-extending compressed air pipes within the chamber, each of said pipes in fluid connection with the compressed air source, each of the pipes oriented parallel to the length of the longitudinal conveyor, the pipes having a series of spaced apart nozzles mounted thereon, a distribution pipe in fluid connection with the air source and the pipes, each of the nozzles having an upper port for receiving heated oven air, a side wall hole for receiving compressed air, a mixing chamber for mixing the compressed air with the oven air to form a hot mix, and a lower port for discharging the mix onto sheets in the oven chamber.

Description

CONVECTIVE METHOD OF HEATING GLASS SHEETS USING COMPRESSED AIR IN CONJUNCTION WITH HEATED OVEN AIR
Field of the Invention The present invention relates to a semi-connective forced air system and method for heating glass sheets for subsequent processing. More particularly, the system and method of the present invention are used for heating low emissivity coated glass sheets (low "e" glass) before tempering and then tempering the glass sheets. The invention includes new and improved nozzles for delivering a hot mixture of compressed air and heated oven air to a sheet of glass inside an oven.
Back ground of the Invention
Previous U.S. Patent 5,591,734, issued on September 14, 1999 to TGL Tempering Systems, Inc., of Cinnaminson, New Jersey, which is incorporated herein by reference, disclosed a semi-connective forced air system for tempering low "e" coated glass sheets that placed air manifolds inside an oven in the direction of flow of the glass sheets. These manifolds have small holes that allow compressed air to be blown onto the glass sheets to assist in the heating process. The air impacting the glass had a temperature of approximately 426°C. The glass sheet must be heated to 634 °C to allow the glass sheet to be tempered. Therefore the convection system had to be turned off once the glass sheet reached the temperature of 426 °C. If the air is kept on too long, the glass sheet exits the oven too cold and breaks. The glass sheet needs to attain the final process temperature of about 634 °C via infrared radiation. This is the slowest form of heat transfer for low "e" glass sheets and it adds extra time to the heating cycle.
Summary of the Invention It is an object of this invention to replace the small holes in the manifolds in U.S. Patent 5,951,734 with new and improved nozzles that pull heated air from the oven, mix it with compressed air to form a hot mix, and blow the hot mix onto the glass sheets. For each cubic foot of compressed air that is put into the nozzle, two (2) cubic feet of oven air is pulled into the nozzle. This allows the convection system to be used for the entire cycle which results in lower cycle times, especially for soft-coat low "e" glasses. In addition, the greater the volume of air moving through the furnace creates higher convection currents that increase the convective heat transfer rate and aids in both faster cycle times and higher quality of glass sheet.
Brief Description of the Drawings
Fig. 1 is a view in side elevation of a compressed air assembly pipe with nozzles inserted therein and with hangers adapted for hanging the pipe from the ceiling of an oven.
Fig. 2 is a view in bottom plan of Fig. 1. Fig. 3 is a view in elevation of a compressed air infeed pipe of Fig. 1.
Fig. 4 is an enlarged view in detail of the area marked 4 in Fig. 3. Fig. 5 is an enlarged view in side elevation of a portion of the pipe and nozzles shown in Fig. 1.
Fig. 5a is an end view of Fig. 5 looking from the left of Fig. 5. Fig. 5b is a view in top plan of one of the nozzles of Fig. 5.
Fig. 6 is a view in bottom plan of Fig. 5. Fig. 7 is a view in rear elevation of a nozzle of Fig. 5. Fig. 8 is a view in front elevation of the nozzle of Fig. 7. Fig. 9 is a view in side elevation of the rollers, pipes, nozzles, clamps, hangers, and compressed air infeed pipes inside an oven.
Fig. 10 is a view in top plan of the pipes and nozzles in the oven. Fig. 11 is a view showing the layout of the aspiration system including air tank, compressed air infeed pipes, distribution pipes and nozzles. Fig. 12a shows a view in side elevation of a pipe flange. Fig. 12b shows a view in elevation of a face of the flange of Fig. 12a looking from the left of Fig. 12a. Fig. 12c shows a view in elevation of the other face of the flange looking from the right of Fig. 12a.
Detailed Description Turning now to the drawings, Fig. 7 shows a view in rear elevation of a nozzle 21, and Fig. 8 shows a view in front elevation of the nozzle 21.
Compressed air goes into nozzle 21 through hole 23 and oven air is pulled into the nozzle through upper port 25 and the compressed and the oven air are mixed in mixing chamber 26 in the lower park of the nozzle 21 to form a hot air mix. The mix of compressed air and oven air is discharged through lower port 27 onto glass sheets S to heat them for further procedures, like tempering.
Hole 23 is an angled hole that has been optimized at 30° for ease of machining, but it can be other angles. The hole diameter is .080 mm, so particles which form inside the compressed air delivery system can blow through these holes. The hole diameter can be changed if necessary or desired.
Upper port 25 is flared at inside flare 29 to allow for easier suction of oven air into this nozzle 21. Lower port 27 is flared inwardly on the outside surface flare 30 of the nozzle 21.
The side view of Fig. 5 and the bottom view of Fig. 6 show the air amplification nozzles 21 pressed through a manifold or pipe 31 which delivers the compressed air to the nozzles 21. Fig. 5b shows the orientation of the hole 23 in nozzle 21 to the manifold pipe 31. The hole 23 is facing toward the opposite wall so that no particles can blow directly into this hole
23 and block it.
Fig. 5 shows a side elevation view of the manifold pipe 31 with the nozzles 21 pressed through it. Fig. 6 shows a bottom view of Fig. 5 of the manifold pipe 31 with the nozzles 21. The number of nozzles 21 per manifold pipe 31 can vary to accommodate the length of the manifold pipe 31. Typically, the nozzles 21 are on 30 cm centers.
Figs. 1 and 2 show an assembly of the compressed air system with the compressed air being fed into the center of pipe 35 between sub-pipes 35a and 35b through the compressed air infeed pipe 33.
The pipes 35a and 35b are supported by hangers 37 which are suspended from the ceiling of the oven.
The compressed air assembly comprises two (2) three-quarter inch pipes 35a and 35b with nozzles 21 pushed through them, a center tee 33 for the compressed air infeed, and flanges 39 to connect cross member 33a of the tee 33 to the pipes 35a and 35b.-The flanges 39 are used so that after the pipes 35a and 35b are heated, they can still be separated and the pipes 35a, 35b may be cleaned, which is done maybe once a year. The pipes 35a, 35b are made out of special stainless steel 310 that produces little scale in the tempering range of a glass furnace.
Figs. 12a, 12b, 12c show the details of the flanges 39 that are used to connect the pipes 35a, 35b to the cross member 33 a of compressed air tee 33. The tee 33 brings the compressed air to the pipes 35a, 35b and into the nozzles 21.
Hangers 37 support the pipes 35a, 35b from the ceiling of the oven.
Figs. 9, 10, and 11 show an aspiration system layout for the present super "e" aspiration system. Note, as in the previous patent No. 5,951,734 that the pipes 35a, 35b are laid out in the direction of travel of the glass sheet travel and are perpendicular to the rolls 41 in the oven 43.
The compressed air comes into the oven 43 through a compressed air infeed distribution pipe 33 and pipes 35a, 35b and by the time it passes through the oven 43 and reaches the nozzle 21 it is at about 426°C, whereupon it is mixed with the hotter oven air which is at about 676°C to 704°C into a mix that is delivered by the nozzles 21 to the glass sheet S at about 690°C.
The glass sheet S is oscillated back and forth in the oven 43 until it reaches the desired temperature for tempering. The semi-convective forced air system for heating glass sheets S comprises a heating chamber 43a in the oven 43, a longitudinal conveyor 43b extending through the heating chamber 43a, a compressed air source 43, a plurality of longitudinally extending compressed air pipes 35 within the chamber 43a, with each of the pipes 35 in fluid connection with the compressed air source, each of the pipes 35 oriented parallel to the length of the longitudinal conveyor 43b, the pipes 35 having a series of spaced apart nozzles 21 mounted thereon, the nozzles 21 being about 30 cm apart, a distribution pipe 33 in fluid connection between the air source 45 and the pipes 35, each of the nozzles 21 having an upper port 25 means for receiving heated oven air, a side wall hole 23 for receiving compressed air, a mixing chamber 21a between hole 23 and lower port 27 for mixing the compressed air with the oven air to form a hot mix, and a lower port 27 for discharging the mix onto sheets S in the oven chamber 43a.

Claims

1. A nozzle for delivering a mixture of compressed air and heated oven air to a sheet of glass inside an oven, comprising: a tube having a center line and a sidewall, said tube having an inside top portion forming an air inlet port for receiving heated oven air from the oven, a hole in the side wall of the tube forming a side wall inlet port for receiving compressed air, a mixing chamber in the tube below the compressed air inlet port for mixing the compressed air with the oven air in the tube to form a mix of oven air and compressed air at a temperature above the temperature of the compressed air, an exit port at the bottom of the tube from which the mix is blown onto a sheet of glass.
2. The invention of claim 1, said hole being at a 30° angle to the center line for causing suction created by the mixing to draw oven air into the top port, said exit port being flared inwardly on the outside of the tube.
3. The invention of claim 1, with means including the nozzle and compressed air delivery pipe to the nozzle for heating the glass sheet to about 634 °C to prepare the glass sheet for tempering.
4. A semi-convective forced air method of heating glass sheets using a mixture of compressed air in conjunction with heated oven air comprising passing a series of glass sheets through an oven containing heated oven air, heating the air in the oven by radiation, passing compressed air into a nozzle in the oven, pulling heated oven air into the nozzle, mixing the compressed air with the heated oven air in the nozzle to form a heated mix of air, blowing the heated mix of air from the nozzle onto a glass sheet moving through the oven to bring it to a temperature suitable for tempering, and tempering the glass sheet.
5. The method of claim 4, including for each cubic foot of compressed air put into the nozzle, pulling in two (2) cubic feet of oven air.
6. The method of claim 4, including heating the oven air to about 676°C , passing compressed air into the oven in a delivery tube at about 38°C and warming the compressed air by the oven air to about 426°C by the time the compressed air reaches the nozzles, and delivering the mix to the glass sheet at about 634 °C.
7. A compressed air assembly for delivering compressed air to nozzles in an oven, comprising two pipes each with a series of spaced apart nozzles pushed through them, the two pipes being aligned with each other with inner ends of the pipes being spaced apart, a center tee for delivering compressed air to the pipes, the center tee having a stem and a cross member, flanges on the ends of the cross member, and flanges on the inner ends of the pipes connecting to the flanges on the cross member, whereby after the pipes are heated they can still be separated by disconnecting the flanges so the pipes may be cleaned.
8. A semi-convective forced air system for heating glass sheets comprising a heating chamber in an oven, a longitudinal conveyor extending through the heating chamber, a compressed air source, a plurality of longitudinally-extending compressed air pipes within the chamber, each of said pipes in fluid connection with the compressed air source, each of the pipes oriented parallel to the length of the longitudinal conveyor,, the pipes having a series of spaced apart nozzles mounted thereon, a distribution pipe in fluid connection with the air source and the pipes, each of the nozzles having an upper port for receiving heated oven air, a side wall hole for receiving compressed air, a mixing chamber for mixing the compressed air with the oven air to form a hot mix, and a lower port for discharging the mix onto sheets in the oven chamber.
PCT/FI2003/000673 2002-09-16 2003-09-16 Convective method of heating glass sheets using compressed air in conjunction with heated oven air WO2004024642A1 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
AU2003262598A AU2003262598A1 (en) 2002-09-16 2003-09-16 Convective method of heating glass sheets using compressed air in conjunction with heated oven air
EP03795038A EP1551775A1 (en) 2002-09-16 2003-09-16 Convective method of heating glass sheets using compressed air in conjunction with heated oven air

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US24479502A 2002-09-16 2002-09-16
US10/244,795 2002-09-16

Publications (1)

Publication Number Publication Date
WO2004024642A1 true WO2004024642A1 (en) 2004-03-25

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ID=31991967

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PCT/FI2003/000673 WO2004024642A1 (en) 2002-09-16 2003-09-16 Convective method of heating glass sheets using compressed air in conjunction with heated oven air

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EP (1) EP1551775A1 (en)
CN (1) CN1330595C (en)
AU (1) AU2003262598A1 (en)
RU (1) RU2287493C2 (en)
WO (1) WO2004024642A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8322162B2 (en) 2004-04-07 2012-12-04 Glaston Services Ltd. Oy Method of heating glass panels for tempering and apparatus applying the method

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5951734A (en) * 1997-08-15 1999-09-14 Tgl Tempering Systems, Inc. Semi-convective forced air system for tempering low E coated glass
EP1279645A2 (en) * 2001-07-27 2003-01-29 Tamglass Ltd. Oy Method and apparatus for heating glass sheets using semi-convective forced air

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4018590A (en) * 1976-03-26 1977-04-19 Ppg Industries, Inc. Fluid spraying apparatus for tempering glass sheets
US4505671A (en) * 1981-02-17 1985-03-19 Glasstech, Inc. Glass sheet roller conveyor furnace including gas jet pump heating
RU2095323C1 (en) * 1995-02-22 1997-11-10 Белгородская государственная технологическая академия строительных материалов Method of heating glass in heat hardening process

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5951734A (en) * 1997-08-15 1999-09-14 Tgl Tempering Systems, Inc. Semi-convective forced air system for tempering low E coated glass
EP1279645A2 (en) * 2001-07-27 2003-01-29 Tamglass Ltd. Oy Method and apparatus for heating glass sheets using semi-convective forced air

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8322162B2 (en) 2004-04-07 2012-12-04 Glaston Services Ltd. Oy Method of heating glass panels for tempering and apparatus applying the method

Also Published As

Publication number Publication date
RU2287493C2 (en) 2006-11-20
CN1678539A (en) 2005-10-05
CN1330595C (en) 2007-08-08
EP1551775A1 (en) 2005-07-13
AU2003262598A1 (en) 2004-04-30
RU2005111221A (en) 2005-09-10

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