CN1330595C - Convective method of heating glass sheets using compressed air in conjunction with heated oven air - Google Patents

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 with compressed air combined with hot furnace air

technical field

The present invention relates to semi-convective pressure/forced air systems and methods for heating glass sheets for subsequent processing. More specifically, the systems and methods of the present invention are used to heat low-E coated glass sheets (low "e" glass) prior to tempering and then temper the glass sheets. The present invention includes a new and improved nozzle for delivering a hot mixture of compressed air and hot furnace air to a glass sheet in a furnace.

technical background

Prior U.S. Patent No. 5,591,734, issued September 14, 1999 to TGL Tempering Systems, Inc. of Cinnaminson, NJ, which discloses a method for tempering low "e" Semi-convective forced air system for tempering coated glass sheets in which the furnace air manifold is placed along the direction of flow/travel of the glass sheets. The holes in these manifolds that allow compressed air to be blown onto the glass sheet to facilitate heat treatment are small. The temperature of the air impinging on the glass (panel) is about 426°C. The glass plate must be heated to 634°C before tempering the glass plate. Therefore once the temperature of the glass plate reaches 426°C, the convection system must be switched off. If the air is kept blowing for too long, the panes will come out too cold and crack. The glass sheet needs to be irradiated by infrared rays to obtain a final processing temperature of about 634°C. This is the slowest form of heat transfer for low "e" glass sheets and adds extra time to the heating cycle.

Contents of the invention

The object of the present invention is to replace the small holes in the manifold of US Patent 5,951,734 with a new and improved lance which draws hot air from the furnace and mixes it with compressed air to form hot mixed air, The hot mixed air is then blown onto the glass plate. For every cubic foot of compressed air introduced into the nozzle, two cubic feet of furnace gas should be sucked into the nozzle. This allows the convection system to be used throughout the cycle, reducing cycle time, especially for soft-coated low "e" glass. In addition, the greater volume of air passing through the furnace creates stronger convection, which increases the rate of convective heat transfer and contributes to both faster cycle times and improved glass sheet quality.

The present invention provides a nozzle for delivering a mixture of compressed air and hot furnace gas to a glass sheet in a furnace, comprising: a tube having a centerline and side walls, the tube having The inside top of the furnace receives an air inlet for hot furnace gas, a hole in the side wall of the tube forming a side wall inlet for receiving compressed air, an inlet for the compressed air in the tube a mixing chamber below the gas port for mixing the compressed air and the furnace gas in the pipe to form a mixture of the furnace gas and the compressed air at a temperature higher than the temperature of the compressed air, and one located at the An exit port at the bottom of the tube through which the mixed air is blown onto the glass plate.

Preferably, the holes are at an angle of 30° to the centreline so that the mixing action creates an attractive force to draw furnace gas into the top port and the discharge port expands inwardly at the outer surface of the tube.

Preferably, an apparatus comprising the lance and a delivery conduit for delivering compressed air to the lance is used for heating the glass sheet to about 634°C to prepare the glass sheet for tempering.

The invention also provides a semi-convective pressurized air method for heating glass sheets using a mixture of compressed air and hot furnace gas, comprising: passing a series of glass sheets through a furnace containing hot furnace gas, heating the air in the furnace by radiation, Compressed air is passed through a nozzle in the furnace, hot furnace gas is sucked into the nozzle, the compressed air is mixed with the hot furnace gas in the nozzle to form a hot air mixture, and the hot air mixture is drawn from the A nozzle blows onto the glass sheet passing through the furnace to bring the glass sheet to a temperature suitable for tempering and to temper the glass sheet.

Preferably, the method includes drawing in two cubic feet of furnace gas for every cubic foot of compressed air passed into the lance.

Preferably, the method comprises: heating the furnace gas to about 676°C, passing compressed air at about 38°C into the furnace in a delivery pipe, and heating the compressed air through the furnace gas so that when the compressed air reaches the The nozzle was heated to about 426°C and the air mixture at about 634°C was delivered to the glass plate.

The present invention also provides a compressed air assembly for delivering compressed air to a lance in a furnace, comprising: two conduits each having a series of spaced apart lances passing therethrough under pressure, the two conduits mutually In line, with the inner ends of the duct spaced apart, a central tee pipe delivering compressed air to the duct, said central tee having a main member and a cross member, French flange, and the flange on the inner end of the conduit connected to the flange on the cross member, whereby after the conduit is heated they can still be separated by removing the flange, thereby allowing the conduit to be cleaned.

The present invention also provides a semi-convective pressurized air system for heating glass sheets, comprising: a heating chamber located within the furnace, a longitudinal conveying mechanism extending through the heating chamber, a source of compressed air, a plurality of longitudinally extending compressed air conduits in the chamber, each of said conduits being fluidly connected to the source of compressed air, each oriented parallel to the length of the longitudinal delivery mechanism, mounted with a series of spaced spray nozzles tube, a distribution tube fluidly connected to an air source and conduit, each of which has an upper port for receiving hot furnace gas, a sidewall hole for receiving compressed air, and a side wall for mixing the compressed air and The furnace air forms a mixing chamber for hot mixed air, and a lower port for discharging the mixed air onto the glass plate in the furnace chamber.

Description of drawings

Figure 1 is a side view of a duct of a compressed air assembly with a nozzle inserted therein and a hanger adapted to suspend the duct from the furnace roof.

FIG. 2 is a bottom view of FIG. 1 .

Fig. 3 is a front view of the compressed air feed pipe in Fig. 1 .

FIG. 4 is an enlarged detail view of the area marked 4 in FIG. 3 .

Figure 5 is an enlarged side view of a portion of the conduit and nozzle shown in Figure 1 .

Figure 5a is an end view of Figure 5 viewed from the left of Figure 5 .

Figure 5b is a top view of one of the nozzles of Figure 5 .

FIG. 6 is a bottom view of FIG. 5 .

FIG. 7 is a rear view of one of the nozzles of FIG. 5. FIG.

FIG. 8 is a front view of the nozzle of FIG. 7 .

Figure 9 is a side view of the rollers, ducts, lances, clamps, hangers and compressed air feed ducts within the furnace.

Figure 10 is a top view of the furnace conduits and nozzles.

Figure 11 shows the arrangement of an aspiration system comprising an air tank, compressed air feed pipe, distribution pipe and spray pipe.

Figure 12a shows a side view of a conduit flange.

Figure 12b shows a front view of one face of the flange in Figure 12a viewed from the left of Figure 12a.

Figure 12c shows a front view of the other face of the flange seen from the right side of Figure 12a.

Detailed ways

Referring now to the drawings, FIG. 7 shows a spout 21 in rear view and FIG. 8 shows the spout 21 in front view. Compressed air enters the lance 21 through holes 23, furnace gas is drawn into the lance through upper ports 25, and the compressed air and furnace gas mix in a mixing chamber 26 in the lower part of the lance 21 to form a hot air mixture. This air mixture of compressed air and furnace gas is discharged through the lower port 27 onto the glass sheet S, thereby heating the glass sheet for further processing, such as tempering.

For ease of processing, the hole 23 has been optimized as a 30° inclined hole, but other angles can also be made. The diameter of the holes is 0.080mm, so particles formed inside the compressed air delivery system can be blown through these holes. The diameter of the holes can be varied as necessary or desired.

The upper port 25 is flared at the inner bell mouth 29 so that furnace gas can be sucked into the nozzle 21 more easily.

The lower port 27 flares inwardly at a flare 30 on the outer surface of the nozzle 21 .

The side view of FIG. 5 and the bottom view of FIG. 6 show the air boost nozzle 21 being pressurized through a manifold or conduit 31 which delivers compressed air to the nozzle 21 . FIG. 5 b shows the orientation of the holes 23 in the nozzle 21 relative to the manifold 31 . The holes 23 face the opposite wall (of the manifold) so that particles are not blown directly into the holes 23 and block them.

Figure 5 shows a side view of the manifold 31 with the lances 21 passing therethrough under pressure.

FIG. 6 shows a bottom view of the manifold 31 with nozzles 21 in FIG. 5 .

The number of nozzles 21 per manifold 31 may vary depending on the length of the manifold 31 . Typically, the center-to-center spacing of the nozzles 21 is 30 cm.

Figures 1 and 2 show a compressed air system assembly in which compressed air is injected through a compressed air feed pipe 33 into the center of conduit 35 between sub-conduits 35a and 35b.

A hanger 37 suspended from the furnace roof supports the conduits 35a and 35b.

The compressed air assembly includes two three-quarter inch conduits 35a and 35b with pressurized nozzles 21 passing therethrough, a central tee 33 for supplying compressed air, and connecting the ends of the tee 33 The cross member 33a is connected to the flanges 39 of the conduits 35a and 35b. This flange 39 is used so that the conduits 35a and 35b can still be separated after they are heated and to allow the conduits 35a and 35b to be cleaned about once a year.

The conduits 35a, 35b are made of special stainless steel 310 that produces only a small scale in the tempering temperature range of the glass furnace.

Figures 12a, 12b, 12c show details of the flange 39 used to connect the conduits 35a, 35b to the cross member 33a of the compressed air tee 33.

Tee 33 brings compressed air to conduits 35a, 35b and into nozzle 21 .

The hanger 37 supports the conduits 35a, 35b from the furnace roof.

Figures 9, 10 and 11 show the arrangement of the suction system for this super "e" suction system. It is to be noted that, as in prior patent No. 5,951,734, the conduits 35a, 35b are arranged in the direction of travel of the glass sheet and perpendicular to the rollers 41 in the furnace 43.

The compressed air enters the furnace 43 through a compressed air feed distribution conduit 33 and conduits 35a, 35b. When the compressed air passes through the furnace 43 and reaches the nozzle 21, it is about 426°C, and is then mixed with the hotter furnace gas of about 676°C to 704°C. The mixing forms mixed air, which is delivered to the glass sheet S through the nozzle 21 at about 690°C.

The glass sheet S is swung back and forth in the furnace 43 until the temperature required for tempering is reached.

The semi-convective compressed air system for heating the glass sheet S comprises: a heating chamber 43a located in the furnace 43; a longitudinal conveying mechanism 43b extending through the heating chamber 43a; a compressed air source 43; Extended compressed air conduits 35, each fluidly connected to a source of compressed air and each oriented parallel to the length of the longitudinal delivery mechanism 43b, are mounted on the conduits 35 with a series of A nozzle 21; a fluid connection between the air source 45 and the distribution conduit 35 between the conduit 35; each nozzle 21 has an upper port 25 to receive hot furnace gas, for receiving the side wall hole 23 of compressed air, with A mixing chamber 21a between the hole 23 and the lower port 27 for mixing compressed air with furnace gas to form hot mixed air, and a lower port for discharging the mixed air onto the glass plate S in the furnace chamber 43a 27.

Claims (8)

1. a mixing air that is used for pressurized air and hot furnace gas is transported to the jet pipe on the sheet glass in the stove, comprising:

One has the pipe of medullary ray and sidewall,

Described pipe has the inside top that is formed for receiving from this stove an air inlet of hot furnace gas,

One is positioned at the hole of this pipe sidewall, and this hole forms one and is used to receive compressed-air actuated sidewall inlet mouth,

One is positioned at the mixing section of this compressed air inlet port of this pipe below, and this mixing section is used for mixing this pressurized air and this furnace gas at this pipe, forming this furnace gas and this compressed-air actuated mixing air that its temperature is higher than this compressed air temperature,

One is positioned at the discharge port of this pipe bottom, and described mixing air blows on this sheet glass by this port.

2. jet pipe according to claim 1 is characterized in that,

Described hole becomes 30 ° of angles with this medullary ray, so that this mixing effect produces magnetism furnace gas is sucked this top port,

Described discharge port at the outside surface of this pipe to intramedullary expansion.

3. jet pipe according to claim 1 is characterized in that,

Utilization comprises this jet pipe and carries the device of compressed-air actuated delivery conduit to this jet pipe, is used for that this sheet glass is heated to about 634 ℃ and is used for the tempered sheet glass with preparation.

4. semi-convection pressure air method of using the mixing air heating glass plate of pressurized air and hot furnace gas comprises:

Make a series of sheet glass by comprising the stove of hot furnace gas,

By the air in this stove of radiation heating,

Pressurized air is fed jet pipe in this stove,

Hot furnace gas is sucked this jet pipe,

The hot furnace gas of this pressurized air and this is mixed in this jet pipe, with formation warm air mixture,

This warm air mixture is blown to this just by on the sheet glass of this stove from this jet pipe, be suitable for the tempered temperature so that this sheet glass reaches, and

This sheet glass is carried out temper.

5. method according to claim 4 is characterized in that, this method comprises:

For each cubic feet pressurized air that feeds this jet pipe, need to suck two cubic feet of furnace gases.

6. method according to claim 4 is characterized in that, this method comprises:

Furnace gas is heated to about 676 ℃,

In a transfer lime, about 38 ℃ pressurized air is fed this stove, and heat this pressurized air by this furnace gas, so that when this pressurized air arrives this jet pipe, be heated to about 426 ℃,

And this about 634 ℃ mixing air is transported on this sheet glass.

7. one kind is used for the pressurized air assembly of compressed air delivery to the jet pipe of stove comprised:

Two respectively have the conduit that the array of spaced pressurized passes jet pipe wherein,

These two conduits mutually in line, and the inner end of this conduit is spaced apart,

One with the center Y-tube of compressed air delivery to this conduit,

Described center Y-tube has a primary member and a transverse member,

Be positioned at the flange at these transverse member two ends,

And with this conduit inner end that flange on this transverse member is connected on flange,

They still can separate by pulling down this flange after this conduit heating thus, thereby can clean conduit.

8. semi-convection pressure air system that is used for heating glass plate comprises:

One is positioned at the heating chamber of this stove,

One extends through the longitudinal delivery mechanism of this heating chamber,

One compressed air source, a plurality of in this heating chamber the air-pressure duct of longitudinal extension,

Each described conduit all is connected with this pressurized air source fluid,

Each this conduit all along the orientated lengthwise that is parallel to this longitudinal delivery mechanism, is equipped with a series of spaced jet pipes on this conduit,

One distribution piping that is connected with catheter fluid with air source,

Each this jet pipe all has a upper port that is used to receive hot furnace gas, one is used to receive compressed-air actuated areole, one is used to mix this pressurized air and this furnace gas forming the mixing section of hot mixing air, and one is used for this mixing air is discharged into lower port on the sheet glass of this furnace chamber.

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