CA1100720A - Continuous ring furnaces of the hoffman type - Google Patents
Continuous ring furnaces of the hoffman typeInfo
- Publication number
- CA1100720A CA1100720A CA324,677A CA324677A CA1100720A CA 1100720 A CA1100720 A CA 1100720A CA 324677 A CA324677 A CA 324677A CA 1100720 A CA1100720 A CA 1100720A
- Authority
- CA
- Canada
- Prior art keywords
- channels
- chambers
- chamber
- rows
- end chamber
- 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
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27B—FURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
- F27B13/00—Furnaces with both stationary charge and progression of heating, e.g. of ring type, of type in which segmental kiln moves over stationary charge
Abstract
ABSTRACT OF THE DISCLOSURE
A continuous ring furnace comprises two rows of side-by-side chambers which are connected in a ring by smoke channels leading from the bottom of each chamber to fire pits of the next chamber in the smoke stream direction.
At each end of the two rows the head channels are divided into two groups which extend between the inner half of each end chamber and the outer half of the other end chamber, thereby crossing over the smoke streams and providing more even heat distribution in the end chambers. An improved building structure permits the use of expansion joints to accommodate expansion stresses.
A continuous ring furnace comprises two rows of side-by-side chambers which are connected in a ring by smoke channels leading from the bottom of each chamber to fire pits of the next chamber in the smoke stream direction.
At each end of the two rows the head channels are divided into two groups which extend between the inner half of each end chamber and the outer half of the other end chamber, thereby crossing over the smoke streams and providing more even heat distribution in the end chambers. An improved building structure permits the use of expansion joints to accommodate expansion stresses.
Description
llOU72() This invention relates to continuous ring furnaces, also called Hoffman furnaces, for baking and rebaking carbon articles. Such furnaces comprise a sequence of chambers connected to one another to form a ring or loop.
In such furnaces the baking or rebaking process comprising a plurality of phases occurs cyclically in turn in all the chambers. More precisely, this process occurs cyclically in groups of chambers and each phase shifts periodically from one group to an adjacent group of chambers after a selected time called the furnace pitch.
The chambers are usually arranged in two adjacent rows, each chamber being connected to the adjacent chamber in the direction of the gas or smoke stream through channels or passages leading from the bottom of the chamber to the fire pits of the adjacent chamber passing under a transversal building structure separating the two chambers.
This arrangement, however, cannot be realized to interconnect end chambers of the two rows and, accordingly, at each end of the two rows the chambers are connected to each other through channels, called head channels, having a U shape in plan view. Each of these channels comprises a first short section directed longitudinally from the bottom of the last chamber of a row and upwardly in the direction of the axis of this row, a substantially horizontal transversal section, perpendicular to the first longitudinal section, and a second short longitudinal section parallel to the first longitudinal section and to the axis of the second row of chambers, which second longitudinal section leads to the lower portion of the fire pit of the adjacent chamber.
Conventional Hoffman furnaces provided with the above-descxibed channels have a drawback in that the temperature is not uniform in the end chambers, this is called the "bend-ing effect".
This drawback is due to the previously described structure of the head channels wherein the gases are not guided but they are free to follow their trend to flow along the shortest way and, for example, to be discharged from the ~9L
.
,~
inner half of the last chamber of a row, and to enter and consequently flow only through the inn~r channels and the corresponding inner half of the first chamber of the other row. This results in an insufficient baking of the articles in the outer halves of the end chambers, wherein hot gases do not flow.
Futhermore, the channels used heretofore have an arc vault shape which prevents the application of expansion jGints so that these channels are subject to substantial expansion stresses which, in time, affect the stability thereof.
An object of this invention is to provide a con-tinuous ring furnace in which the drawback of the bending effect is avoided or at least reduced.
According to this invention there is provided a continuous ring furnace comprising a plurality of chambers arranged side-by-side in two rows, the chambers being inter-connected by channels each of which in each row of chambers leads from the bottom of one chamber to fire pits of the next chamber in the direction of a smoke stream, the chambers at each end of the two rows being interconnected by head channels which also lead in the direction of the smoke stream, the head channels at each end of the two rows generally having a U-shape in plan view and comprising a first group of channels leading from the bottom of an outer part of one end chamber to fire pits of an inner part of the other end chamber and a second group of channels leading from the bottom of an inner part of said one end chamber to fire pits of an outer part of said other end chamber, said outer and inner parts of the chambers being relative to longitudinal axes of the respective rows of chambers.
Preferably each of said first and second groups of channels comprises a plurality of longitudinal channel sections leading from the bottom of the respective end chamber, a substantially horizontal section which is common to said longitudinal channel sections and extends transversely of the rows of chambers, and a plurality of longitudinal channel .
...
, 110(~7Z0 sections leading from the common horizontal section to the bottoms of fire pits of the respective next end chamber in the smoke stream direction.
Conveniently each channel of said first and second group of channels has a structure comprising capital forming elements supported by side walls, said elements supporting in turn supporting plates having a vertical section shaped as an extremely flattened rr, said plates supporting overlay-ing layers.
The invention facilitates the provision of a furnace of the Hoffman type provided with head channels suitably distributing the hot gas streams discharged from the last chamber of a row within the first chamber of the other row, thus preventing these streams from flowing only along the shortest path and heating only parts of the chambers. The furnace can have an improved building structure of the head channels or passages wherein a certain number of expansion joints can be inserted by virtue of the fact that the supporting plates need not be cambered, which expansion joints allow such building structure to expand and contract without affecting the stability thereof.
The invention will be further understood from the following description by way of example of an embodiment thereof with reference to the accompanying drawings, in which:
Figure 1 is a schematic plan view of part of a ring furnace, showing a pair of chambers at an end of the furnace and the head channels connecting these chambers to each other;
Figures 2 to 5 are schematic vertical sectional views taken on lines 2-2 to 5-5 respectively of Figure l; and Figure 6 is a front elevational view showing the structure of the head channels.
Figure 1 shows end chambers 10 and 11 of a ring furnace connected to each other by six head channels divided into two groups 12 and 13 of three channels each. These channels comprise a first section A leading from the chamber 10 and a second section B leading to the chamber 11.
llOU7ZO
As is clearly shown in the drawings, the three channels 12A, conveying the gases discharged from the lower part of the outer half of the chamber 10, lead to the upper part of the inner half of the chamberll through the channels 12B and inner fire pits 12C (Figure 3),and the three channel~
13A lead from the lower part of the inner half of the chamber 10 to the upper part of the outer half of the chamber 11 through the channels 13B and outer fire pits 13C (Figure 5) thus obtaining a "crossing" of the gas streams discharging from the chamber 10.
The arrangement of head channels 12 and 13 is completed by separate transversal channels 14 and 15 one for each group of channels 12 and 13 respectively.
It will be noted that, for purposes of illustration, the direction of the smoke stream in the above-described head channels is indicated by white arrows for channels 12 and black arrows for channels 13.
Figure 6 shows the structure of the channels 12 (the channels 13 are of an identical structure), which structure comprises capital forming elements 20 supported by defining walls 21 of the channels which support supporting plates 22, having the shape of an extremely flattened T, which plates support in turn the overlaying layers.
As is clearly shown, this structure, contrary to arc-shaped structures, allows the interposition of vertical expansion joints 23. Expansion joints 23 allow the building structure of the channels to expand when subjected to the hot smoke stream, without affecting the position and stability of the structure.
It should be appreciated that the above-described arrangement of the head channels is provided at each end of the ring furnace. The invention is not limited to the above-described embodiment as comprising two groups of three channels, and extends to all possible embodiments thereof which cross the gas streams discharged from the last chamber of a row of chambers and flowing to the first chamber of the other row of chambers in a continuous ring furnace of the Hoffman type, so as to eliminate the bending effect.
,
In such furnaces the baking or rebaking process comprising a plurality of phases occurs cyclically in turn in all the chambers. More precisely, this process occurs cyclically in groups of chambers and each phase shifts periodically from one group to an adjacent group of chambers after a selected time called the furnace pitch.
The chambers are usually arranged in two adjacent rows, each chamber being connected to the adjacent chamber in the direction of the gas or smoke stream through channels or passages leading from the bottom of the chamber to the fire pits of the adjacent chamber passing under a transversal building structure separating the two chambers.
This arrangement, however, cannot be realized to interconnect end chambers of the two rows and, accordingly, at each end of the two rows the chambers are connected to each other through channels, called head channels, having a U shape in plan view. Each of these channels comprises a first short section directed longitudinally from the bottom of the last chamber of a row and upwardly in the direction of the axis of this row, a substantially horizontal transversal section, perpendicular to the first longitudinal section, and a second short longitudinal section parallel to the first longitudinal section and to the axis of the second row of chambers, which second longitudinal section leads to the lower portion of the fire pit of the adjacent chamber.
Conventional Hoffman furnaces provided with the above-descxibed channels have a drawback in that the temperature is not uniform in the end chambers, this is called the "bend-ing effect".
This drawback is due to the previously described structure of the head channels wherein the gases are not guided but they are free to follow their trend to flow along the shortest way and, for example, to be discharged from the ~9L
.
,~
inner half of the last chamber of a row, and to enter and consequently flow only through the inn~r channels and the corresponding inner half of the first chamber of the other row. This results in an insufficient baking of the articles in the outer halves of the end chambers, wherein hot gases do not flow.
Futhermore, the channels used heretofore have an arc vault shape which prevents the application of expansion jGints so that these channels are subject to substantial expansion stresses which, in time, affect the stability thereof.
An object of this invention is to provide a con-tinuous ring furnace in which the drawback of the bending effect is avoided or at least reduced.
According to this invention there is provided a continuous ring furnace comprising a plurality of chambers arranged side-by-side in two rows, the chambers being inter-connected by channels each of which in each row of chambers leads from the bottom of one chamber to fire pits of the next chamber in the direction of a smoke stream, the chambers at each end of the two rows being interconnected by head channels which also lead in the direction of the smoke stream, the head channels at each end of the two rows generally having a U-shape in plan view and comprising a first group of channels leading from the bottom of an outer part of one end chamber to fire pits of an inner part of the other end chamber and a second group of channels leading from the bottom of an inner part of said one end chamber to fire pits of an outer part of said other end chamber, said outer and inner parts of the chambers being relative to longitudinal axes of the respective rows of chambers.
Preferably each of said first and second groups of channels comprises a plurality of longitudinal channel sections leading from the bottom of the respective end chamber, a substantially horizontal section which is common to said longitudinal channel sections and extends transversely of the rows of chambers, and a plurality of longitudinal channel .
...
, 110(~7Z0 sections leading from the common horizontal section to the bottoms of fire pits of the respective next end chamber in the smoke stream direction.
Conveniently each channel of said first and second group of channels has a structure comprising capital forming elements supported by side walls, said elements supporting in turn supporting plates having a vertical section shaped as an extremely flattened rr, said plates supporting overlay-ing layers.
The invention facilitates the provision of a furnace of the Hoffman type provided with head channels suitably distributing the hot gas streams discharged from the last chamber of a row within the first chamber of the other row, thus preventing these streams from flowing only along the shortest path and heating only parts of the chambers. The furnace can have an improved building structure of the head channels or passages wherein a certain number of expansion joints can be inserted by virtue of the fact that the supporting plates need not be cambered, which expansion joints allow such building structure to expand and contract without affecting the stability thereof.
The invention will be further understood from the following description by way of example of an embodiment thereof with reference to the accompanying drawings, in which:
Figure 1 is a schematic plan view of part of a ring furnace, showing a pair of chambers at an end of the furnace and the head channels connecting these chambers to each other;
Figures 2 to 5 are schematic vertical sectional views taken on lines 2-2 to 5-5 respectively of Figure l; and Figure 6 is a front elevational view showing the structure of the head channels.
Figure 1 shows end chambers 10 and 11 of a ring furnace connected to each other by six head channels divided into two groups 12 and 13 of three channels each. These channels comprise a first section A leading from the chamber 10 and a second section B leading to the chamber 11.
llOU7ZO
As is clearly shown in the drawings, the three channels 12A, conveying the gases discharged from the lower part of the outer half of the chamber 10, lead to the upper part of the inner half of the chamberll through the channels 12B and inner fire pits 12C (Figure 3),and the three channel~
13A lead from the lower part of the inner half of the chamber 10 to the upper part of the outer half of the chamber 11 through the channels 13B and outer fire pits 13C (Figure 5) thus obtaining a "crossing" of the gas streams discharging from the chamber 10.
The arrangement of head channels 12 and 13 is completed by separate transversal channels 14 and 15 one for each group of channels 12 and 13 respectively.
It will be noted that, for purposes of illustration, the direction of the smoke stream in the above-described head channels is indicated by white arrows for channels 12 and black arrows for channels 13.
Figure 6 shows the structure of the channels 12 (the channels 13 are of an identical structure), which structure comprises capital forming elements 20 supported by defining walls 21 of the channels which support supporting plates 22, having the shape of an extremely flattened T, which plates support in turn the overlaying layers.
As is clearly shown, this structure, contrary to arc-shaped structures, allows the interposition of vertical expansion joints 23. Expansion joints 23 allow the building structure of the channels to expand when subjected to the hot smoke stream, without affecting the position and stability of the structure.
It should be appreciated that the above-described arrangement of the head channels is provided at each end of the ring furnace. The invention is not limited to the above-described embodiment as comprising two groups of three channels, and extends to all possible embodiments thereof which cross the gas streams discharged from the last chamber of a row of chambers and flowing to the first chamber of the other row of chambers in a continuous ring furnace of the Hoffman type, so as to eliminate the bending effect.
,
Claims (3)
1. A continuous ring furnace comprising a plurality of chambers arranged side-by-side in two rows,the chambers being interconnected by channels each of which in each row of chambers leads from the bottom of one chamber to fire pits of the next chamber in the direction of a smoke stream, the chambers at each end of the two rows being interconnected by head channels which also lead in the direction of the smoke stream, the head channels at each end of the two rows generally having a U-shape in plan view and comprising a first group of channels leading from the bottom of an outer part of one end chamber to fire pits of an inner part of the other end chamber and a second group of channels leading from the bottom of an inner part of said one end chamber to fire pits of an outer part of said other end chamber, said outer and inner parts of the chambers being relative to longitudinal axes of the respective rows of chambers.
2. A continuous ring furnace as claimed in claim 1 wherein each of said first and second groups of channels comprises a plurality of longitudinal channel sections leading from the bottom of the respective end chamber, a substantially horizontal section which is common to said longitudinal channel sections and extends transversely of the rows of chambers, and a plurality of longitudinal channel sections leading from the common horizontal section to the bottoms of fire pits of the respective next end chamber in the smoke stream direct-ion.
3. A continuous ring furnace as claimed in claim 2 wherein each channel of said first and second group of channels has a structure comprising capital forming elements supported by side walls, said elements supporting in turn supporting plates having a vertical section shaped as an extremely flattened T, said plates supporting overlaying layers.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| IT48697/78A IT1101894B (en) | 1978-03-31 | 1978-03-31 | IMPROVEMENT IN HOFFMAN TYPE RING OVENS |
| IT48697A/78 | 1978-03-31 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1100720A true CA1100720A (en) | 1981-05-12 |
Family
ID=11268101
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA324,677A Expired CA1100720A (en) | 1978-03-31 | 1979-03-30 | Continuous ring furnaces of the hoffman type |
Country Status (6)
| Country | Link |
|---|---|
| AR (1) | AR217358A1 (en) |
| BR (1) | BR7901930A (en) |
| CA (1) | CA1100720A (en) |
| DE (1) | DE2911924A1 (en) |
| GB (1) | GB2017884B (en) |
| IT (1) | IT1101894B (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| USD377173S (en) | 1995-04-20 | 1997-01-07 | John Manufacturing Limited | Combined radio with flourescent lantern, spotlight and blinking light |
| CN102435069A (en) * | 2011-12-22 | 2012-05-02 | 郑州祥通耐火陶瓷有限公司 | Roasting device of carbon product |
-
1978
- 1978-03-31 IT IT48697/78A patent/IT1101894B/en active
-
1979
- 1979-03-27 GB GB7910708A patent/GB2017884B/en not_active Expired
- 1979-03-27 DE DE19792911924 patent/DE2911924A1/en not_active Withdrawn
- 1979-03-29 BR BR7901930A patent/BR7901930A/en unknown
- 1979-03-30 CA CA324,677A patent/CA1100720A/en not_active Expired
- 1979-03-30 AR AR276026A patent/AR217358A1/en active
Also Published As
| Publication number | Publication date |
|---|---|
| GB2017884B (en) | 1982-10-13 |
| AR217358A1 (en) | 1980-03-14 |
| DE2911924A1 (en) | 1979-10-18 |
| BR7901930A (en) | 1979-10-23 |
| GB2017884A (en) | 1979-10-10 |
| IT1101894B (en) | 1985-10-07 |
| IT7848697A0 (en) | 1978-03-31 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |