CA1095698A - Method of repairing furnace roofs during heat-up - Google Patents
Method of repairing furnace roofs during heat-upInfo
- Publication number
- CA1095698A CA1095698A CA314,719A CA314719A CA1095698A CA 1095698 A CA1095698 A CA 1095698A CA 314719 A CA314719 A CA 314719A CA 1095698 A CA1095698 A CA 1095698A
- Authority
- CA
- Canada
- Prior art keywords
- bricks
- roof
- brick
- mortar
- furnace
- 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.)
- Expired
Links
- 238000000034 method Methods 0.000 title claims abstract description 10
- 239000011449 brick Substances 0.000 claims abstract description 59
- 239000004570 mortar (masonry) Substances 0.000 claims abstract description 18
- 238000009998 heat setting Methods 0.000 claims description 3
- 239000011521 glass Substances 0.000 abstract description 5
- 238000010438 heat treatment Methods 0.000 abstract description 3
- 238000002844 melting Methods 0.000 abstract description 3
- 230000008018 melting Effects 0.000 abstract description 3
- 238000006125 continuous glass melting process Methods 0.000 description 2
- 241000269333 Caudata Species 0.000 description 1
- BDAGIHXWWSANSR-UHFFFAOYSA-N Formic acid Chemical compound OC=O BDAGIHXWWSANSR-UHFFFAOYSA-N 0.000 description 1
- 208000036366 Sensation of pressure Diseases 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000007598 dipping method Methods 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 238000003780 insertion Methods 0.000 description 1
- 230000037431 insertion Effects 0.000 description 1
- 229920000136 polysorbate Polymers 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
- 230000000087 stabilizing effect Effects 0.000 description 1
- 230000000007 visual effect Effects 0.000 description 1
Landscapes
- Furnace Housings, Linings, Walls, And Ceilings (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A method for preventing the dropping of individual bricks from a sprung arch roof employed in a continuous tank-type glass melting furnace, the dropping of the bricks normally occur-ring during heat-up of the furnace. The slightly tapered bricks employed in constructing the roof are oriented with their long axis in the vertical direction and, as heating occurs and the structure differentially expands and the bricks dry out, some be-come sufficiently loose to drop from the roof into the tank of the furnace. In visually observing the interior surface of the roof during heat-up, it can be seen which bricks are settling and likely to drop therefrom. These bricks are pulled up through the roof from above by a suction cup and mortar is placed around the bricks. The bricks are then dropped back into place with the mortar holding the bricks until they become wedged firmly in place as the temperature of the roof increases.
A method for preventing the dropping of individual bricks from a sprung arch roof employed in a continuous tank-type glass melting furnace, the dropping of the bricks normally occur-ring during heat-up of the furnace. The slightly tapered bricks employed in constructing the roof are oriented with their long axis in the vertical direction and, as heating occurs and the structure differentially expands and the bricks dry out, some be-come sufficiently loose to drop from the roof into the tank of the furnace. In visually observing the interior surface of the roof during heat-up, it can be seen which bricks are settling and likely to drop therefrom. These bricks are pulled up through the roof from above by a suction cup and mortar is placed around the bricks. The bricks are then dropped back into place with the mortar holding the bricks until they become wedged firmly in place as the temperature of the roof increases.
Description
~9s69~
This invention relates to sprung arch roofs or crowns of continuous glass melting furnaces, and more particularly to the problems resulting from the non-uniform temperatures encountered during heat-up of the furnace which cause portions of the overall structure, as well as the individual bricks employed in construc-ting the arched refractory roofs, to expand at different times.
Conventionally, sprung arch roofs as employed in con-tinuous glass melting furnaces spring from skews running the en-tire length of the furnace, the skews being set on heel plates firmly at~ached to the buckstays forming part of the furnace super-structure. Conventionally, the roof is built up of individual, tapered, like-sized refractory bricks which may be set in an over-lapping pattern like the checker pattern of a conventional brick wall. An example of such a roof is shown in United States Patent No. 2,236,~20 issued on April 1, 1941. The constructlon of such roof may be accomplished by simply dipping the individual bricks in a siliceous mortar and setting them in place on a form support-ed by scaffolding. When the form on which the roof has been laid during construction is removed, the slight elastic yielding of the buckstays and tie rods, together with the beddin~-ln of the con-tactlng surfaces of adJacent bricks against each other, allows the crown of the roof to drop sllghtly and small gaps to open be-tween the lower ends of the bricks. Thereafter, when the furnace is heated up, the bricks expand and raise the crown to its origi-nal posltion.
Newly constructed roofs as above-described are often vary damp, and they are slowly dried out over a period of time (10 to 12 days), by temporary burners such as salamanders placed at convenient locations about the furnace. During this time, the temperst~re throughout the furnace and the roof will not be uni-form. It is the usual practice in glass melting furnaces to .,. ~k ~L~J~3~
construct the arches of sillca bricks, which exhibit their maxi-mum thermal expansion at low temperatures such as those encounter-ed ~uring the drying-out period. Accordingly, it may be found that the br~cks expand at different times or the crown may warp during the drying-out period by rising unequally ln one part or another with respect to the plane of symmetry of the tank. Con-sequently, as heating occurs and the bricks dry out, somP may be-come sufficiently loose to drop fsom the roof arches ineo the ln-terior of the furnace.
In the past, bricks dropping out of the roof have been replaced by driving larger, wedge-shaped bricks into the openings after the ori~inal bricks have fallen, with the new bricks being initially held in place due to their larger size, and then by their expansion as heat-up continues. This procedure is not entirely satisfactory in that it requires the insertion of a cold, larFer size brick into an arch of the heated bricks, causing the pressure on the bricks to be increased as the heat-up continues since the ends of the arches are held in a fixed position by the skew backs.
As a result, the bricks may spall or be crushed and a section of the roof may fall. Another disadvantage is that it is necessary to retrieve the fallen bricks from the tank so that they will not con~aminate the glass to be produced therein.
The above-mentioned disadvantages are overcome by the procedure of this lnventlon whlch comprlses the steps of visually inspectlng the interior surface of the arches of the roof to see which bricks are settling and protruding from the interlor surface, grasping the extending brick~s from above by a suction cup; pulling the bricks back up through the roof, coating the bricks with mortar and dropplng them back into their place in the roof; the mortar holdlng the bricks until they become firmly wedged in place as the temperature of the roof increa~es.
9~ 8 An ob~ect of ~his invention ls to provide a method for preventing the dropping of bricks from a sprung arch roof of a glass melting furnace during heat-up.
According to the present invention, there is provided a method of preventing individual bricks from dropping from a sprung arch roof of a furnace during in~tial heat-up thereof, character-ized by the steps of visually observing the interior surface of said sprung arch roof and detecting any individual brick which changes position and pro~ects below said surface, graspinR said individual brick pro~ecting from the top and removing sa~d brick from said roof, applying mortar to the sides of said removed brick, and reinserting sald mortar coated brick in said roof.
In the acccmpanying drawlngs:
Fig. 1 is a transverse fragmentary perspective view, partly in section, showing a portion of the interior and illus-trating bricks settling in the roof;
Fig. 2 is an enlarged, fragmentary, sectional view of~
one of the arches of the roof showing a brick settled from its normal position ~ust prior to belng removed from the arch; and Fig. 3 is a view similar to Fig. 2 but showing a removed brlck coated with mortar ~ust prior to its being reset in the arch.
As illustrated in Flg. 1, only the upper portion of a ; glass meltlng furnace 10 is shown as the invention relates specif-ically to a sprung arch roof or crown 11 therefor. As therein illustrated, the meltin& furnace 10 includes a chamber 12 bounded by ~amb w811s 13 and 14, buttressed by buckstays 15 connected to-gether by tie rods 16 for stabilizing the furnace structure.
Located on the top of each of the ~amb walls 13 and 14 are skew blocks 17 and 18 which run the entire length of the cham-ber 12 and are sultably supported as upon longitudinally extending I-bea~s 19, for example, which are rigidly secured to the buck-stays 15.
~9~
Springing from the skew blocks 17 and 18 is the sprung arch roof 11 which is normally built-up of a plurality of individ-ual refractory bricks 20 measuring 18 inches (45.72 cm) in length, 9 inches (22.86 cm) in width and tapering from a thickness of 3 inches (7.62 cm) across the top to 2-7/8 inches (6.30 cm) across the bottom. As is common practice, the bricks 20 are layed in overlapping courses 21 with their long axes orieneed in a vertical direction with a heat setting mortar 22, one that sets at about 2000 F. (1093 C.), (see Fig. 2) between their ~oints. Accord-ingly, the roof 11 as a whole is composed of a series of these courses 21 interlocked together and becomes a monolithic structure after the mortar sets.
With the sprung roof 11 formed as just described, it will be obvious that as the furnace is initially heated and the drying out and heating up process proceeds, the individual bricks 20 in the roof will expand as they absorb heat, and that since they are set with a mortar that does not harden until it reaches a rela-tively high temperature, the brlcks will be free to move relative to each other.
As previously indicated, the furnace is initially heated by temporary burners placed at various locations about the fur-nace, and thus the temperature throughout the furnace may not be uniform. Thus, the individual bricks 20 wlll absorb heat at dif-ferent rates and expand accordingly. This differential absorption of heat by the bricks will loosen some to the point that they may settle and pro~ect through the interior surface of the roof 11.
In accordance with the invention, the interior surface of the roof 11 ls kept under visual surveillance and when an in-dividual brick 20~ is observed to settle and pro~ect into the 3~ chamber 12, the top of the brick 20' is grasped by a suct~on de-vice 23 (see Figs. 2 and 3) connected to a source of vacuum pres-sure (not shown) by a hose 24. As indicated in Fig. 3, the brick ~56~8 20' is lifted out of the roof 11, coated with additional mortar such as the heat setting mortar 22, and then pushed back into place in the roof. It has been found that this additional mortar will hold the brick until it becomes wedged firmlg ln place as the heat-up continues and the temperature of the roof increases.
_ 5 _ .
This invention relates to sprung arch roofs or crowns of continuous glass melting furnaces, and more particularly to the problems resulting from the non-uniform temperatures encountered during heat-up of the furnace which cause portions of the overall structure, as well as the individual bricks employed in construc-ting the arched refractory roofs, to expand at different times.
Conventionally, sprung arch roofs as employed in con-tinuous glass melting furnaces spring from skews running the en-tire length of the furnace, the skews being set on heel plates firmly at~ached to the buckstays forming part of the furnace super-structure. Conventionally, the roof is built up of individual, tapered, like-sized refractory bricks which may be set in an over-lapping pattern like the checker pattern of a conventional brick wall. An example of such a roof is shown in United States Patent No. 2,236,~20 issued on April 1, 1941. The constructlon of such roof may be accomplished by simply dipping the individual bricks in a siliceous mortar and setting them in place on a form support-ed by scaffolding. When the form on which the roof has been laid during construction is removed, the slight elastic yielding of the buckstays and tie rods, together with the beddin~-ln of the con-tactlng surfaces of adJacent bricks against each other, allows the crown of the roof to drop sllghtly and small gaps to open be-tween the lower ends of the bricks. Thereafter, when the furnace is heated up, the bricks expand and raise the crown to its origi-nal posltion.
Newly constructed roofs as above-described are often vary damp, and they are slowly dried out over a period of time (10 to 12 days), by temporary burners such as salamanders placed at convenient locations about the furnace. During this time, the temperst~re throughout the furnace and the roof will not be uni-form. It is the usual practice in glass melting furnaces to .,. ~k ~L~J~3~
construct the arches of sillca bricks, which exhibit their maxi-mum thermal expansion at low temperatures such as those encounter-ed ~uring the drying-out period. Accordingly, it may be found that the br~cks expand at different times or the crown may warp during the drying-out period by rising unequally ln one part or another with respect to the plane of symmetry of the tank. Con-sequently, as heating occurs and the bricks dry out, somP may be-come sufficiently loose to drop fsom the roof arches ineo the ln-terior of the furnace.
In the past, bricks dropping out of the roof have been replaced by driving larger, wedge-shaped bricks into the openings after the ori~inal bricks have fallen, with the new bricks being initially held in place due to their larger size, and then by their expansion as heat-up continues. This procedure is not entirely satisfactory in that it requires the insertion of a cold, larFer size brick into an arch of the heated bricks, causing the pressure on the bricks to be increased as the heat-up continues since the ends of the arches are held in a fixed position by the skew backs.
As a result, the bricks may spall or be crushed and a section of the roof may fall. Another disadvantage is that it is necessary to retrieve the fallen bricks from the tank so that they will not con~aminate the glass to be produced therein.
The above-mentioned disadvantages are overcome by the procedure of this lnventlon whlch comprlses the steps of visually inspectlng the interior surface of the arches of the roof to see which bricks are settling and protruding from the interlor surface, grasping the extending brick~s from above by a suction cup; pulling the bricks back up through the roof, coating the bricks with mortar and dropplng them back into their place in the roof; the mortar holdlng the bricks until they become firmly wedged in place as the temperature of the roof increa~es.
9~ 8 An ob~ect of ~his invention ls to provide a method for preventing the dropping of bricks from a sprung arch roof of a glass melting furnace during heat-up.
According to the present invention, there is provided a method of preventing individual bricks from dropping from a sprung arch roof of a furnace during in~tial heat-up thereof, character-ized by the steps of visually observing the interior surface of said sprung arch roof and detecting any individual brick which changes position and pro~ects below said surface, graspinR said individual brick pro~ecting from the top and removing sa~d brick from said roof, applying mortar to the sides of said removed brick, and reinserting sald mortar coated brick in said roof.
In the acccmpanying drawlngs:
Fig. 1 is a transverse fragmentary perspective view, partly in section, showing a portion of the interior and illus-trating bricks settling in the roof;
Fig. 2 is an enlarged, fragmentary, sectional view of~
one of the arches of the roof showing a brick settled from its normal position ~ust prior to belng removed from the arch; and Fig. 3 is a view similar to Fig. 2 but showing a removed brlck coated with mortar ~ust prior to its being reset in the arch.
As illustrated in Flg. 1, only the upper portion of a ; glass meltlng furnace 10 is shown as the invention relates specif-ically to a sprung arch roof or crown 11 therefor. As therein illustrated, the meltin& furnace 10 includes a chamber 12 bounded by ~amb w811s 13 and 14, buttressed by buckstays 15 connected to-gether by tie rods 16 for stabilizing the furnace structure.
Located on the top of each of the ~amb walls 13 and 14 are skew blocks 17 and 18 which run the entire length of the cham-ber 12 and are sultably supported as upon longitudinally extending I-bea~s 19, for example, which are rigidly secured to the buck-stays 15.
~9~
Springing from the skew blocks 17 and 18 is the sprung arch roof 11 which is normally built-up of a plurality of individ-ual refractory bricks 20 measuring 18 inches (45.72 cm) in length, 9 inches (22.86 cm) in width and tapering from a thickness of 3 inches (7.62 cm) across the top to 2-7/8 inches (6.30 cm) across the bottom. As is common practice, the bricks 20 are layed in overlapping courses 21 with their long axes orieneed in a vertical direction with a heat setting mortar 22, one that sets at about 2000 F. (1093 C.), (see Fig. 2) between their ~oints. Accord-ingly, the roof 11 as a whole is composed of a series of these courses 21 interlocked together and becomes a monolithic structure after the mortar sets.
With the sprung roof 11 formed as just described, it will be obvious that as the furnace is initially heated and the drying out and heating up process proceeds, the individual bricks 20 in the roof will expand as they absorb heat, and that since they are set with a mortar that does not harden until it reaches a rela-tively high temperature, the brlcks will be free to move relative to each other.
As previously indicated, the furnace is initially heated by temporary burners placed at various locations about the fur-nace, and thus the temperature throughout the furnace may not be uniform. Thus, the individual bricks 20 wlll absorb heat at dif-ferent rates and expand accordingly. This differential absorption of heat by the bricks will loosen some to the point that they may settle and pro~ect through the interior surface of the roof 11.
In accordance with the invention, the interior surface of the roof 11 ls kept under visual surveillance and when an in-dividual brick 20~ is observed to settle and pro~ect into the 3~ chamber 12, the top of the brick 20' is grasped by a suct~on de-vice 23 (see Figs. 2 and 3) connected to a source of vacuum pres-sure (not shown) by a hose 24. As indicated in Fig. 3, the brick ~56~8 20' is lifted out of the roof 11, coated with additional mortar such as the heat setting mortar 22, and then pushed back into place in the roof. It has been found that this additional mortar will hold the brick until it becomes wedged firmlg ln place as the heat-up continues and the temperature of the roof increases.
_ 5 _ .
Claims (3)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A method of preventing individual bricks from drop-ping from a sprung arch roof of a furnace during initial heat-up thereof, characterized by the steps of visually observing the in-terior surface of said sprung arch roof and detecting any individ-ual brick which changes position and projects below said surface, grasping said individual brick projecting from the top and re-moving said brick from said roof, applying mortar to the sides of said removed brick, and reinserting said mortar coated brick in said roof.
2. A method of preventing individual bricks from drop-ping from a sprung arch roof as claimed in claim 1, characterized in that the top of said brick is grasped by a vacuum device.
3. A method of preventing individual bricks from drop-ping from a sprung arch roof as claimed in claim 1 or claim 2, characterized in that said mortar is a heat setting mortar which does not set until it reaches a temperature of about 2000° F.
(1093° C.).
(1093° C.).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA314,719A CA1095698A (en) | 1978-10-30 | 1978-10-30 | Method of repairing furnace roofs during heat-up |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA314,719A CA1095698A (en) | 1978-10-30 | 1978-10-30 | Method of repairing furnace roofs during heat-up |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1095698A true CA1095698A (en) | 1981-02-17 |
Family
ID=4112741
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA314,719A Expired CA1095698A (en) | 1978-10-30 | 1978-10-30 | Method of repairing furnace roofs during heat-up |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1095698A (en) |
-
1978
- 1978-10-30 CA CA314,719A patent/CA1095698A/en not_active Expired
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |