CA2123244A1 - Natural gas tin float bath roof - Google Patents
Natural gas tin float bath roofInfo
- Publication number
- CA2123244A1 CA2123244A1 CA 2123244 CA2123244A CA2123244A1 CA 2123244 A1 CA2123244 A1 CA 2123244A1 CA 2123244 CA2123244 CA 2123244 CA 2123244 A CA2123244 A CA 2123244A CA 2123244 A1 CA2123244 A1 CA 2123244A1
- Authority
- CA
- Canada
- Prior art keywords
- bath
- roof
- tin
- gas
- elongated
- Prior art date
- Legal status (The legal status 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 status listed.)
- Abandoned
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- Gas Burners (AREA)
Abstract
A tin float bath with an entirely new heat-insulating bath roof comprising two parts, first, an elongated steel chamber of an inverted U-shape fabrication with sinusoidal-layered ceramic fiber blankets and ceramic fiber boards and, second, side-mounted or top-mounted parallel automatic recuperative natural gas burners. The controlled cooling of the flat glass is accomplished with no problems of contaminating the bath atmosphere, the flat glass or the molten tin.
Description
NATURAL GAS TIN FLOAT BATH ROOF
(Continuation in part of Application Ser No. 07/920,399) BACKGROUND OF THE lN~N'llON
This invention relates generally to the controlled cooling of the molten flat glass ribbon as it passes through the tin float bath at a continuous rate. Manufacturing flat glass comprises the delivering of molten glass to a bath of molten tin and advancing the glass along the surface of the tin under thermal conditions that do not contaminate the internal atmosphere.
Such contamination is detrimental to both the glass product and the molten tin. Glass at approximately 1900 degrees F enters the bath from the melting tank and at approximately 1200 degrees F exits the bath to a cooling lehr. In prior art installations the temperatures in the bath are maintained with electrical resistance heaters suspended from the roof over the ribbon of glass. Such electrical heaters do not contaminate the bath atmosphere. The metal plate shell of the prior art bath roof is protected from the heat with an internal refractory lining, which has little or no heat-insulating qualities and isolates the electrical equipment plenum above from the heated cavity. This prior art construction has been used over the past twenty-five year period. Attempts to burn natural gas over the bath by the glass industry failed the industry's contamination requirements.
SUMMARY OF THE INVENTION
The construction of an entirely new operational roof for the tin float bath comprises two parts, the newly designed fabri-~ Page 2 cation of the bath roof and the use of automatic recuperative natural gas burners instead of the prior art electrical heating elements. Individually, both the new fabrication and gas burners contribute to a cost-efficient operation that highly excels the prior art operation.
The fabrication of the new roof housing utilizes a one-half inch steel plate furnace shell of a required depth to allow the installation of the gas burners in either a horizontal or a vertical position. The interior insulation of the new furnace shell consists of a layered ceramic fiber lining of blanket modules, "Firewall Bonded 22," and two one-inch thick boards, "Fiberfrax Duraboard," type RG, maintaining a temperature differential from 2200 degrees F inside the shell to an approximately 200 degrees F outside the shell. No cooling chamber is required above the new bath enclosure as is necessary to protect the prior art electrical equipment and materials of the prior art tin float bath. Such cooling chamber causes a condensation of tin oxide/tin sulfide on the suspended internal refractory lining which then becomes a contaminate of the glass.
The use of the new automatic recuperative natural gas burners in the tin float bath process will result in the following operational cost advantages. The utilization of natural gas is more cost-efficient than electricity, approximately a conserva-tive seventy percent savings in this case. The new gas burnerinstallation encompasses few moving parts, easy insertion of the burners through the mounting flange even during full opera-- 21232~
tion, only two piping connections for gas and combustion air, and simple HIGH-FIRE, LOW-FIRE, OFF control. Glass production is a twenty-four hour daily operation throughout the mechanical life of the bath. Burned out or broken electrical heaters periodically cause prior art operational adjustments to maintain glass flow until quality is affected and complete shut down then becomes necessary. Any shutdown costs are prohibi-tive, thousands of dollars per minute. Prior art shutdowns entail stopping the glass flow, cooling the bath, raising the roof, replacing the failed electrical heaters with new, making electrical reconnections, lowering the roof, reheating the bath and again establishing the glass flow in its proper atmosphere.
This prior art shutdown encompasses engineering, demolition and installation for a ninety day period during which no glass is produced. With the new automatic recuperative gas burners no shutdown is necessary. Seldom will the gas burners fail. If one does require replacement, it can be readily removed and replaced. This replacement will take approximately two hours, during which time the glass flows continuously with no inter-ruptions. The longevity of the installation is increasedsubstantially because, first, the new burners are capable of withstanding the corrosive nature of tin oxide/tin sulfide and, also, the new layered ceramic fiber lining does not deteriorate.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a plan view of a prior art tin float bath showing heating zones and electrical heating transformers.
212324~
~ Page 4 Figure 2 is a longitudinal elevation of a prior art tin float bath showing the bath roof and the bath bottom and the heating transformers mounted on the roof support structure.
Figure 3 is a transverse section of a prior art tin float bath taken along line 3-3 of Figure 1 detailing the electrical materials and equipment. This section is typical throughout the length of the prior art bath.
Figure 4 is a plan view of the new tin float bath showing how the electrical installation and the prior art bath roof of Figure 1 has been omitted and replaced with the new bath roof and the natural gas burners arranged in parallel.
Figure 5 is a longitudinal elevation of the new tin float bath showing the new side mounted natural gas burners.
Figure 6 is a transverse section of the new tin float bath taken at the plan line 6-6 of Figure 4 showing the absence of the electrical heating materials, equipment and the prior art bath roof, and their replacement with the new bath roof and the new side-mounted natural gas burners.
Figure 7 is similar to Figure 6 except with top vertical mounted new natural gas burners. Either section or both is typical throughout the length of the new bath.
Figure 8 is a detail of the construction of the new bath roof with the layered ceramic fiber lining.
Figure 9 is a detailed cutaway view of the new automatic recuperative natural gas burner.
Figure 10 is a piping and instrumentation diagram showing the natural gas supply pipe with its main gas valve train, the natural gas header pipe, the combustion air blower, the combustion air header pipe, associated valves, and with the requisite taps, adjustable valves, burners and instruments.
Figure 10 is typical of all zones having four burners. Zones with six, ~even or eight burners are provided similarly and from the same gas and air headers. See Figure 11 for the quantity of burners per zone.
Figure 11 is a heating conversion chart showing the connected kilowatts, the quantity of the prior art electrical heating elements, the total rated BTU's for each of the prior art thirty-two electrical zones of the prior art tin float bath, the proposed burner zone BTU requirements, the quantity of burners per burner zone, burner information and total BTU's for each of the twenty-four gas burner zones. This chart presents the calculated natural gas requirements to operate the new tin float bath and to determine how cost efficient and energy efficient the new bath is as opposed to the prior art bath.
See Figure 12 for comparative costs.
FIGURE 12 is a bath operation cost comparison chart presenting with the total annual cost of operating a prior art bath with electricity and the new bath with natural gas. This does not include the cost savings that will result from the new bath roof with the layered ceramic fiber lining. This savings can be determined only during operation.
FIGURE 13 is a chart showing the quantities of the electrical equipment and materials from the prior art tin float bath that will not be included in the installation of the new tin float 21232~
bath with automatic recuperative gas burners.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
An explanation of the prior art tin float bath must precede the detailed presentation of this invention. In order that this invention may be understood more readily, references to the accompanying figures will be made.
FIGURE 1 is a plan view of a prior art typical tin float bath with electrical heating zones numbered 1 through 32 and with the associated zone transformers, numbered 1" through 32".
Glass enters the bath from the right and exits from the left.
FIGURE 2 is a longitudinal elevation of the prior art bath showing the bath roof 33, the bath bottom 34 and the heating transformer locations above.
FIGURE 3 is a transverse section taken on the line 3-3 of Figure 1, detailing the electrical materials internal to the prior art bath roof and consisting of copper bus bars 35 terminating in the bus box 36 and connectors 37. Cables 38 connect bus bars 35 to the electrical heating elements 39 and to the transformers 3" and 8" above. Figure 3 is typical through the length of the bath. Electrical resistance heaters 39 are shown extended into the bath atmosphere 40 over the glass ribbon 41 floating on the tin 42. The prior art bath roof 33 is suspended separately from the bath bottom 34 by a support structure 43. The prior art bath roof 33 with all of its associated electrical equipment and materials as shown in Figures 1, 2 and 3 shall be removed in its entirety and replaced with a new bath roof 331 as shown in Figure 6. The - 21232~
prior art support structure 43 will remain to support the new bath roof 331. The quantities of electrical items eliminated with the prior art roof are listed on Figure 13.
FIGURE 4 is a plan view of the new tin float bath showing the locations of one hundred eighteen natural gas burners 44 in their respective heating zones in parallel. Glass enters the bath from the right and exits from the left. The new bath roof 331 is shown on Figure 5, 6, 7 and 8.
FIGURE 5 is a longitudinal elevation of the new tin float bath showing the locations of the natural gas burners 44 mounted through the side walls of the new bath roof 331.
FIGURE 6 is a transverse section taken along the line B-B of Figure 4 showing the new bath roof 331 with the side-mounted natural gas burners 44 installed horizontally. Space 45 is allocated for both natural gas and combustion air header pipes.
FIGURE 7 shows the natural gas burners 44 installed in parallel vertically through the top of the new bath roof 331.
Either or both of the horizontal or vertical installations can be utilized and the depth of the new bath roof 331 will be altered accordingly.
FIGURE 8 shows the construction details of the new bath roof 331. The shell 80 of the new bath roof is fabricated of one-half inch plate steel and is made rigid with an I-beam and angle framework 84. The shell 80 and the framework 84 are suspended from the support structure 43. The interior of the shell housing is insulated with layers of ceramic fiber blanket modules 81, "Firewall Bonded 22," and two one-inch thick, 212324~
~ Page 8 rigid, high temperature ceramic fiber boards 82, "Fiberfrax Duraboard," type RG, all as manufactured by The Carborundum Company. This insulation provides the following advantages, lower heat losses, faster heat-up and cool-down cycles, lower installed costs, easy repairs, thermal shock resistance, high heat internal reflectance, good sound absorption, excellent corrosion resistance and longer life of the new bath.
Side seal blocks 83 seal the void between the new roof 331 and the present bath bottom 34. Items 47, 49, 50 and 52 of the burners 44 are described as part of Figure 9.
FIGURE 9 is a cutaway view of the automatic recuperative natural gas burner similar to that as fabricated with Kanthal APM by Eclipse Combustion of Rockford IL. Each burner consists of an ignition and heat-radiating chamber 46 for operation up to 2370 degrees F, a flanged mount 47 welded to the external bath steel shell 48, complete with gas inlet 49, air inlet 50, air metering orifice 51, an exhaust outlet 52 and the internals with a burner nozzle 53. This particular burner type is capable of withstanding the corrosive nature of the tin oxidet tin sulfide present in the bath atmosphere.
The preceding paragraph refers primarily to the preparation of the new bath roof. The remaining equipment, instruments, piping and valves are shown on Figure 10, a typical piping and instrumentation diagram. The explanation of Figure 10 will describe the operation for the installation with the horizontal burners. The operation with the vertical burners is similar.
A four burner zone 7 is shown. Zones with six, seven and eight - 212~2~
-burners are similar, differing only in the quantity of burners.
Two blowers, the main gas supply with valve train, the control valves and instruments provide combustion air and gas to the gas burners on both sides of the bath.
Natural gas is provided via a four inch gas line 54 to the main gas valve train 55, consisting of: two manual shut-off valves, a pressure regulating valve, two electrically-operated manually-reset shut-off valves with electrical interlocks, a vent valve with an electrical interlock and pressure switch with an electrical interlock. All electrical interlocks 78 are connected to the ignition section of the burner control panel.
The four inch natural gas line 56 continues from the main gas valve train as the main gas supply header running along total bath length in allocated space 45, Figure 6.
Combustion air is provided by a centrifugal blower 57 via an eight inch main air supply header 59. A pressure switch 58 with an electrical interlock 79 is utilized to sense correct air header pressure. This eight inch main air supply header 59 continues along total bath length in space 45, Figure 6.
The four inch main gas supply header 56 along both sides of the length of the bath is tapped at each burner zone location to form a one inch secondary gas header 61. Located at the beginning of the one inch secondary gas header are two valves.
The first is the burner zone secondary gas header ON-OFF
solenoid valve 62 with an electrical interlock 79. The second is the burner zone secondary gas header proportionator valve 63 with a proportionator impulse line 64 tapped into the secondary ~ Page 10 air supply header 60. This proportionator valve is required to maintain the proper natural gas to air ratio required for combustion within the automatic recuperative burner 44. The one inch secondary gas header 61 is continued from the proportionator valve and is tapped with a one-half inch line 65 connected to the zone automatic recuperative burner 44. This line is provided with an adjustable valve 66.
The eight inch main air supply header 59 along both sides of the length of the bath is tapped at each burner zone location to provide a four inch secondary air supply header 60. Located at the beginning of the four inch secondary air supply header is an electrically-operated motor-driven valve 67, which regulates the combustion air flow. The motor-driven valve 67 is provided with a two-position switch 68 which indicates LOW-FIRE or HIGH-FIRE conditions. Both the motor-driven valve and the two-position switch have electrical interlocks 79. The four inch secondary air supply header 60 is continued from the motor-driven valve 67 and is tapped with a one inch air line 69 connected to the zone automatic recuperative burner 44. This line is provided with an adjustable shut-off valve 70.
In addition, the automatic recuperative burner 44 is provided with a two inch exhaust stack 71 to atmosphere. Each automatic recuperative burner is furnished with an ignition system. This system comprises an ignition transformer 72, ignition plug 73 and an ultraviolet flame detector 74. Associated with this system are a timer 75, a relay 76 and an indicating light 77 mounted in the ignition section of the burner control panel.
Each zone burner has its respective interlock 79. All 79 interlocks are part of the DCS, Distributive Control System.
In each burner 44 combustion air and natural gas are ignited and burned within the heat-radiating chamber 46. The residue from the burnt gases is exhausted externally to the bath and has no contact with the atmosphere inside the bath. As the burnt gases move through the chamber to the exhaust outlet 52, they preheat the incoming gas and air for a more efficient operation.
One burner control panel for the control of both sides of the bath has three functional sections: main valve train control, the burner ignition control and flame monitoring control. The operational status of all burners is indicated at this panel.
If one burner fails to ignite, or fails to continue operating, the operating personnel knows immediately the condition and location of that particular burner and will initiate the corrective procedures.
(Continuation in part of Application Ser No. 07/920,399) BACKGROUND OF THE lN~N'llON
This invention relates generally to the controlled cooling of the molten flat glass ribbon as it passes through the tin float bath at a continuous rate. Manufacturing flat glass comprises the delivering of molten glass to a bath of molten tin and advancing the glass along the surface of the tin under thermal conditions that do not contaminate the internal atmosphere.
Such contamination is detrimental to both the glass product and the molten tin. Glass at approximately 1900 degrees F enters the bath from the melting tank and at approximately 1200 degrees F exits the bath to a cooling lehr. In prior art installations the temperatures in the bath are maintained with electrical resistance heaters suspended from the roof over the ribbon of glass. Such electrical heaters do not contaminate the bath atmosphere. The metal plate shell of the prior art bath roof is protected from the heat with an internal refractory lining, which has little or no heat-insulating qualities and isolates the electrical equipment plenum above from the heated cavity. This prior art construction has been used over the past twenty-five year period. Attempts to burn natural gas over the bath by the glass industry failed the industry's contamination requirements.
SUMMARY OF THE INVENTION
The construction of an entirely new operational roof for the tin float bath comprises two parts, the newly designed fabri-~ Page 2 cation of the bath roof and the use of automatic recuperative natural gas burners instead of the prior art electrical heating elements. Individually, both the new fabrication and gas burners contribute to a cost-efficient operation that highly excels the prior art operation.
The fabrication of the new roof housing utilizes a one-half inch steel plate furnace shell of a required depth to allow the installation of the gas burners in either a horizontal or a vertical position. The interior insulation of the new furnace shell consists of a layered ceramic fiber lining of blanket modules, "Firewall Bonded 22," and two one-inch thick boards, "Fiberfrax Duraboard," type RG, maintaining a temperature differential from 2200 degrees F inside the shell to an approximately 200 degrees F outside the shell. No cooling chamber is required above the new bath enclosure as is necessary to protect the prior art electrical equipment and materials of the prior art tin float bath. Such cooling chamber causes a condensation of tin oxide/tin sulfide on the suspended internal refractory lining which then becomes a contaminate of the glass.
The use of the new automatic recuperative natural gas burners in the tin float bath process will result in the following operational cost advantages. The utilization of natural gas is more cost-efficient than electricity, approximately a conserva-tive seventy percent savings in this case. The new gas burnerinstallation encompasses few moving parts, easy insertion of the burners through the mounting flange even during full opera-- 21232~
tion, only two piping connections for gas and combustion air, and simple HIGH-FIRE, LOW-FIRE, OFF control. Glass production is a twenty-four hour daily operation throughout the mechanical life of the bath. Burned out or broken electrical heaters periodically cause prior art operational adjustments to maintain glass flow until quality is affected and complete shut down then becomes necessary. Any shutdown costs are prohibi-tive, thousands of dollars per minute. Prior art shutdowns entail stopping the glass flow, cooling the bath, raising the roof, replacing the failed electrical heaters with new, making electrical reconnections, lowering the roof, reheating the bath and again establishing the glass flow in its proper atmosphere.
This prior art shutdown encompasses engineering, demolition and installation for a ninety day period during which no glass is produced. With the new automatic recuperative gas burners no shutdown is necessary. Seldom will the gas burners fail. If one does require replacement, it can be readily removed and replaced. This replacement will take approximately two hours, during which time the glass flows continuously with no inter-ruptions. The longevity of the installation is increasedsubstantially because, first, the new burners are capable of withstanding the corrosive nature of tin oxide/tin sulfide and, also, the new layered ceramic fiber lining does not deteriorate.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a plan view of a prior art tin float bath showing heating zones and electrical heating transformers.
212324~
~ Page 4 Figure 2 is a longitudinal elevation of a prior art tin float bath showing the bath roof and the bath bottom and the heating transformers mounted on the roof support structure.
Figure 3 is a transverse section of a prior art tin float bath taken along line 3-3 of Figure 1 detailing the electrical materials and equipment. This section is typical throughout the length of the prior art bath.
Figure 4 is a plan view of the new tin float bath showing how the electrical installation and the prior art bath roof of Figure 1 has been omitted and replaced with the new bath roof and the natural gas burners arranged in parallel.
Figure 5 is a longitudinal elevation of the new tin float bath showing the new side mounted natural gas burners.
Figure 6 is a transverse section of the new tin float bath taken at the plan line 6-6 of Figure 4 showing the absence of the electrical heating materials, equipment and the prior art bath roof, and their replacement with the new bath roof and the new side-mounted natural gas burners.
Figure 7 is similar to Figure 6 except with top vertical mounted new natural gas burners. Either section or both is typical throughout the length of the new bath.
Figure 8 is a detail of the construction of the new bath roof with the layered ceramic fiber lining.
Figure 9 is a detailed cutaway view of the new automatic recuperative natural gas burner.
Figure 10 is a piping and instrumentation diagram showing the natural gas supply pipe with its main gas valve train, the natural gas header pipe, the combustion air blower, the combustion air header pipe, associated valves, and with the requisite taps, adjustable valves, burners and instruments.
Figure 10 is typical of all zones having four burners. Zones with six, ~even or eight burners are provided similarly and from the same gas and air headers. See Figure 11 for the quantity of burners per zone.
Figure 11 is a heating conversion chart showing the connected kilowatts, the quantity of the prior art electrical heating elements, the total rated BTU's for each of the prior art thirty-two electrical zones of the prior art tin float bath, the proposed burner zone BTU requirements, the quantity of burners per burner zone, burner information and total BTU's for each of the twenty-four gas burner zones. This chart presents the calculated natural gas requirements to operate the new tin float bath and to determine how cost efficient and energy efficient the new bath is as opposed to the prior art bath.
See Figure 12 for comparative costs.
FIGURE 12 is a bath operation cost comparison chart presenting with the total annual cost of operating a prior art bath with electricity and the new bath with natural gas. This does not include the cost savings that will result from the new bath roof with the layered ceramic fiber lining. This savings can be determined only during operation.
FIGURE 13 is a chart showing the quantities of the electrical equipment and materials from the prior art tin float bath that will not be included in the installation of the new tin float 21232~
bath with automatic recuperative gas burners.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
An explanation of the prior art tin float bath must precede the detailed presentation of this invention. In order that this invention may be understood more readily, references to the accompanying figures will be made.
FIGURE 1 is a plan view of a prior art typical tin float bath with electrical heating zones numbered 1 through 32 and with the associated zone transformers, numbered 1" through 32".
Glass enters the bath from the right and exits from the left.
FIGURE 2 is a longitudinal elevation of the prior art bath showing the bath roof 33, the bath bottom 34 and the heating transformer locations above.
FIGURE 3 is a transverse section taken on the line 3-3 of Figure 1, detailing the electrical materials internal to the prior art bath roof and consisting of copper bus bars 35 terminating in the bus box 36 and connectors 37. Cables 38 connect bus bars 35 to the electrical heating elements 39 and to the transformers 3" and 8" above. Figure 3 is typical through the length of the bath. Electrical resistance heaters 39 are shown extended into the bath atmosphere 40 over the glass ribbon 41 floating on the tin 42. The prior art bath roof 33 is suspended separately from the bath bottom 34 by a support structure 43. The prior art bath roof 33 with all of its associated electrical equipment and materials as shown in Figures 1, 2 and 3 shall be removed in its entirety and replaced with a new bath roof 331 as shown in Figure 6. The - 21232~
prior art support structure 43 will remain to support the new bath roof 331. The quantities of electrical items eliminated with the prior art roof are listed on Figure 13.
FIGURE 4 is a plan view of the new tin float bath showing the locations of one hundred eighteen natural gas burners 44 in their respective heating zones in parallel. Glass enters the bath from the right and exits from the left. The new bath roof 331 is shown on Figure 5, 6, 7 and 8.
FIGURE 5 is a longitudinal elevation of the new tin float bath showing the locations of the natural gas burners 44 mounted through the side walls of the new bath roof 331.
FIGURE 6 is a transverse section taken along the line B-B of Figure 4 showing the new bath roof 331 with the side-mounted natural gas burners 44 installed horizontally. Space 45 is allocated for both natural gas and combustion air header pipes.
FIGURE 7 shows the natural gas burners 44 installed in parallel vertically through the top of the new bath roof 331.
Either or both of the horizontal or vertical installations can be utilized and the depth of the new bath roof 331 will be altered accordingly.
FIGURE 8 shows the construction details of the new bath roof 331. The shell 80 of the new bath roof is fabricated of one-half inch plate steel and is made rigid with an I-beam and angle framework 84. The shell 80 and the framework 84 are suspended from the support structure 43. The interior of the shell housing is insulated with layers of ceramic fiber blanket modules 81, "Firewall Bonded 22," and two one-inch thick, 212324~
~ Page 8 rigid, high temperature ceramic fiber boards 82, "Fiberfrax Duraboard," type RG, all as manufactured by The Carborundum Company. This insulation provides the following advantages, lower heat losses, faster heat-up and cool-down cycles, lower installed costs, easy repairs, thermal shock resistance, high heat internal reflectance, good sound absorption, excellent corrosion resistance and longer life of the new bath.
Side seal blocks 83 seal the void between the new roof 331 and the present bath bottom 34. Items 47, 49, 50 and 52 of the burners 44 are described as part of Figure 9.
FIGURE 9 is a cutaway view of the automatic recuperative natural gas burner similar to that as fabricated with Kanthal APM by Eclipse Combustion of Rockford IL. Each burner consists of an ignition and heat-radiating chamber 46 for operation up to 2370 degrees F, a flanged mount 47 welded to the external bath steel shell 48, complete with gas inlet 49, air inlet 50, air metering orifice 51, an exhaust outlet 52 and the internals with a burner nozzle 53. This particular burner type is capable of withstanding the corrosive nature of the tin oxidet tin sulfide present in the bath atmosphere.
The preceding paragraph refers primarily to the preparation of the new bath roof. The remaining equipment, instruments, piping and valves are shown on Figure 10, a typical piping and instrumentation diagram. The explanation of Figure 10 will describe the operation for the installation with the horizontal burners. The operation with the vertical burners is similar.
A four burner zone 7 is shown. Zones with six, seven and eight - 212~2~
-burners are similar, differing only in the quantity of burners.
Two blowers, the main gas supply with valve train, the control valves and instruments provide combustion air and gas to the gas burners on both sides of the bath.
Natural gas is provided via a four inch gas line 54 to the main gas valve train 55, consisting of: two manual shut-off valves, a pressure regulating valve, two electrically-operated manually-reset shut-off valves with electrical interlocks, a vent valve with an electrical interlock and pressure switch with an electrical interlock. All electrical interlocks 78 are connected to the ignition section of the burner control panel.
The four inch natural gas line 56 continues from the main gas valve train as the main gas supply header running along total bath length in allocated space 45, Figure 6.
Combustion air is provided by a centrifugal blower 57 via an eight inch main air supply header 59. A pressure switch 58 with an electrical interlock 79 is utilized to sense correct air header pressure. This eight inch main air supply header 59 continues along total bath length in space 45, Figure 6.
The four inch main gas supply header 56 along both sides of the length of the bath is tapped at each burner zone location to form a one inch secondary gas header 61. Located at the beginning of the one inch secondary gas header are two valves.
The first is the burner zone secondary gas header ON-OFF
solenoid valve 62 with an electrical interlock 79. The second is the burner zone secondary gas header proportionator valve 63 with a proportionator impulse line 64 tapped into the secondary ~ Page 10 air supply header 60. This proportionator valve is required to maintain the proper natural gas to air ratio required for combustion within the automatic recuperative burner 44. The one inch secondary gas header 61 is continued from the proportionator valve and is tapped with a one-half inch line 65 connected to the zone automatic recuperative burner 44. This line is provided with an adjustable valve 66.
The eight inch main air supply header 59 along both sides of the length of the bath is tapped at each burner zone location to provide a four inch secondary air supply header 60. Located at the beginning of the four inch secondary air supply header is an electrically-operated motor-driven valve 67, which regulates the combustion air flow. The motor-driven valve 67 is provided with a two-position switch 68 which indicates LOW-FIRE or HIGH-FIRE conditions. Both the motor-driven valve and the two-position switch have electrical interlocks 79. The four inch secondary air supply header 60 is continued from the motor-driven valve 67 and is tapped with a one inch air line 69 connected to the zone automatic recuperative burner 44. This line is provided with an adjustable shut-off valve 70.
In addition, the automatic recuperative burner 44 is provided with a two inch exhaust stack 71 to atmosphere. Each automatic recuperative burner is furnished with an ignition system. This system comprises an ignition transformer 72, ignition plug 73 and an ultraviolet flame detector 74. Associated with this system are a timer 75, a relay 76 and an indicating light 77 mounted in the ignition section of the burner control panel.
Each zone burner has its respective interlock 79. All 79 interlocks are part of the DCS, Distributive Control System.
In each burner 44 combustion air and natural gas are ignited and burned within the heat-radiating chamber 46. The residue from the burnt gases is exhausted externally to the bath and has no contact with the atmosphere inside the bath. As the burnt gases move through the chamber to the exhaust outlet 52, they preheat the incoming gas and air for a more efficient operation.
One burner control panel for the control of both sides of the bath has three functional sections: main valve train control, the burner ignition control and flame monitoring control. The operational status of all burners is indicated at this panel.
If one burner fails to ignite, or fails to continue operating, the operating personnel knows immediately the condition and location of that particular burner and will initiate the corrective procedures.
Claims (6)
1. Apparatus for making sheet glass comprising an elongated chamber having an elongated bottom of U-shaped cross-section, molten tin supported by said elongated bottom, a molten glass ribbon supported by said molten tin, said elongated chamber having an elongated heat-insulating roof of inverted U-shaped cross-section, and a multiplicity of recuperative gas burners in spaced parallel relationship extending through both sides of said roof, each of said recuperative gas burners having a closed end portion overlying said molten glass ribbon and having a nozzle for producing a gas flame in said closed end portion and having a sleeve spaced inwardly of said closed end portion and surrounding said gas burner nozzle to provide, internally of said sleeve, a space for introducing air and gas to said gas burner and to provide, externally of said sleeve, a space for exhausting burnt gas, whereby the gas flame is not exposed to the atmosphere surrounding said molten tin and molten glass ribbon, therefore will not contaminate said atmosphere, the molten tin or the molten glass.
2. The combination recited in claim l wherein each of said recuperative gas burners is mounted in the sidewalls of said elongated, heat-insulating roof in parallel relation with each other.
3. The combination recited in claim 1 wherein each of said recuperative gas burners is mounted vertically in the top of said elongated, heat-insulating roof.
4. The combination recited in claim 1 wherein said elongated, heat-insulating roof is of sinusoidal-layered ceramic fiber blankets and ceramic fiber boards, which prevent tin oxide/tin sulfide from condensing inside said roof and contaminating the glass and the tin.
5. The combination recited in claim 1 wherein said recuperative gas burners exceeds 100.
6. The combination recited in claim 1 wherein the closed end portion of each of said recuperative gas burners is of substantially semi-spherical shape.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US08/186,628 | 1994-01-26 | ||
| US08/186,628 US5427598A (en) | 1992-07-27 | 1994-01-26 | Natural gas tin float bath roof |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2123244A1 true CA2123244A1 (en) | 1995-07-27 |
Family
ID=22685686
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2123244 Abandoned CA2123244A1 (en) | 1994-01-26 | 1994-05-10 | Natural gas tin float bath roof |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2123244A1 (en) |
-
1994
- 1994-05-10 CA CA 2123244 patent/CA2123244A1/en not_active Abandoned
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