CA1098307A - Cooler for shaft furnace - Google Patents
Cooler for shaft furnaceInfo
- Publication number
- CA1098307A CA1098307A CA294,995A CA294995A CA1098307A CA 1098307 A CA1098307 A CA 1098307A CA 294995 A CA294995 A CA 294995A CA 1098307 A CA1098307 A CA 1098307A
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- Canada
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- pipes
- heat
- plate
- coolant
- cooler
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Abstract
COOLER FOR SHAFT FURNACE
Abstract of the disclosure A cooler for a shaft furnace comprises a metal plate adapted to protect the furnace walls from the heat effect and arranged in the way of heat flow and a means for cooling said plate, made in the form of metal pipes filled with a coolant and sealed at the ends thereof. The coolant-filled ends of the pipes are rigidly fixed to the plate, the coolant-free ends of said pipes being mounted within a cooling chamber with the coolant circulating therethrough. The cooling chamber is arranged exteriorly of the furnace wall. he coolant-free ends of the pipes are disposed slightly above those filled with the coolant. The plate is formed of two layers, namely, a high-heat-conducting layer and a low-heat-conducting one, the former facing the furnace working space and the latter being presented to the furnace wall. The interfacial plane of the layers is parallel to the longitudinal axis of the pipes.
The present invention can be advantageously used for the protection of blast-furnace shells.
Abstract of the disclosure A cooler for a shaft furnace comprises a metal plate adapted to protect the furnace walls from the heat effect and arranged in the way of heat flow and a means for cooling said plate, made in the form of metal pipes filled with a coolant and sealed at the ends thereof. The coolant-filled ends of the pipes are rigidly fixed to the plate, the coolant-free ends of said pipes being mounted within a cooling chamber with the coolant circulating therethrough. The cooling chamber is arranged exteriorly of the furnace wall. he coolant-free ends of the pipes are disposed slightly above those filled with the coolant. The plate is formed of two layers, namely, a high-heat-conducting layer and a low-heat-conducting one, the former facing the furnace working space and the latter being presented to the furnace wall. The interfacial plane of the layers is parallel to the longitudinal axis of the pipes.
The present invention can be advantageously used for the protection of blast-furnace shells.
Description
10~83~7 BACKGROU~D OF THE INVENT ION
The present invention relates to cooling arrangements for protecting the walls of metallurgical furnaces from heat, and more particularly to shaft-furnace coolers~
The invention can be advantageously applied for the protection of blast-furnace shells.
Because of elevated temperatures created in the working space of a blast furnace, the shell-thereof is subjected to severe heat. Therefore, special arrangements are called for to insure mechanical strength of such shells and protect them from heat loads. The arrangements in question are plate coolers which are usually mounted on the furnace shell at the side of the furnace working space.
It is modern practice to intensify the blast-furnace process by raising the blast temperature, increasing the amount of oxygen contained in the blast, or else by building up pressure in the furnace space. The above factors are detrimental to the operation of heat-protecting arrangements, placing more stringent requirements upon their ability to resist heat.
There are known in the art plate coolers which comprise a cast-iron plate with built-in steel pipes whose open ends extend beyond the plate and through the furnace shell. The pipes are connected through said ends with the furnace cooling circuit through which circulates a coolant, such as industrial or chemically treated water, or vapour-water mixture.
~0~83~)7 In the course of the blast-furnace operation, the plate is e~posed to heat loads which vary timewise. As a result, the plate tends to change its geometrical dimensions, expanding and contracting. The plate expansion and shrinkage adversely affect the pipes which are rigidly connected therewith. The process of manufacturing coolers is such that it causes embrittlement of steel pipes which are subjected to carbonization in the process of casting molten iron therein. The ends of the pipes extending through the furnace shell are usually we~lided thereto. With the iron plate acting upon said pipes, there creates therein periodi-cally variable pressures which bring about their destruction.
As a result, the coolant passing from the furnace cooling circuit penetrates through the damaged pipe into the furnace working space. This calls for higher fuel input per unit of production because of the heat losses require~or the evaporation of the escaped coolant. In some cases, the penetration of considerable amount of coolant to the furnace may even disrupt the furnace operating process.
At present, for lack of reliable and prompt trouble-shooting techniques, it takes considerable time and human effort to spot and disconnect the damaged pipe. The atten-ding personnel involved in such operation are compelled to work in the conditions of severe gas contamination and high temperatures.
10"83~7 It is deemed necessary to point out still another dis-advantage of the hereinbefore described coolers. There is pro-vided in the furnace cooling circuit, with a plurality of coolers being connected thereto, gravity circulation of the coolant. This type of the coolant circulation depends for its rate on the average heat load acting on the coolers. With the lining being broken away from the surface of the cooler plate, the latter is exposed to severe heating which can be eliminated only by increasing the rate of vapor-water mixture circulation through the pipes intended for cooling the plate. As mentioned above, however, the rate of circulation depends solely on the average heat load acting on the group of coolers, which practi-cally remains unaltered. Therefore, the increased amount of heat effecting a separate plate results in greater amount of vapor in the pipes cooling this plate, which, in turn, causes its overheating and fusion.
A construction in accordance with the present invention includes a cooler for a shaft furnace comprising a plate adapted to protect the furnace wall body against the effect of heat flux to which it is exposed and formed of two layers, a high heat-conducting layer facing the furnace working space and a low heat-conducting one presented to the furnace wall, a means for cooling said plate, made in the form of metal pipes partially filled with a coolant and sealed at the ends thereof, the longi-tudinal axis of said pipes being parallel to the interfacial plane of said layers, a cooling chamber arranged exteriorly of the furnace wall body and having a coolant circulating there-through, ends of said pipes partially filled with a coolant _ 4 -10~83~7 being rigidly connected to said plate, ends of said pipes free from coolant, arranged slightly above those filled therewith and mounted in said cooling chamber.
In other words, in order to improve the cooling of the cooler plate by a sudden increase of the flow rate of heat affecting said cooler and eliminating the possibility of the water penetration into a metallurgical furnace, there has been developed a cooler comprising a plate with pipes whose ends at one side thereof are built into said plate, filled with a coolant and sealed. The other ends of the pipes, which are mounted higher than those filled with water, extend beyond the plate and pass through the furnace shell into a cooling chamber wherein they - 4a -10"83~7 are fixed. Circulating in the cooling chamber is a coolant.
The cooling chamber is arranged exteriorly of the furnace and connected to the cooling circuit thereof.
The improved cooling of the plate of each separate cooler has been accomplished by way of sealing the ends of the cooler plate pipes, whereby each pipe is provided with its own circuit wherein the vapour-water mixture circulation is determined by the heat loads acting on such circuit. The rate of vapour-water mixture circulation in the plate-cooling pipes increases with the heat load acting on the plate, thereby providing for reliab~e cooling of said plate.
The use of such cooler practically eliminates the coolant penetration to the furnace in case of damage of the sealed pipe, since there is but a negligible amount of coolant contained therein, with the furnace cooling circuit, wherein circulates water, being separated from the interior of the damaged pipe by the wall of the latter. This being the cooler construction,the pipe is surrounded with the cast-iron plate, having therefore, its entire surface exposed to heat. It happens that certain heat flows cause abundant formation of vapour in the part of the pipe which is fixed in the plate, and the condensate, formed in the free part of the pipe due to condensation of vapour passing there~nto through a cooling chamber, is prevented from descending to the lower part of the pipe. Thus, the water from the part of the pipe fixed in the plate is rushed to the upper part of the pipe. This results in the overheating of the pipe and 10"8307 plate walls because of the absence of the heat outlet leading to the furnace cooling circuit, and the destruction of the cooler thus becomes in~vitable.
To eliminate the above-mentioned disadvantage, there has been proposed a cooler for a metallurgical shaft furnace, comprising a plate with built-in pipes whose ends at one side thereof are filled with a coolant and sealed.
Ihe other ends of said pipes are disposed above tho~e filled with the coolant and extend beyond the plate and through the furnace shell into a cooling chamber to be fixed therein`, said chamber being connected to the furnace cooling circuit with a coolant circulating therethrough. Fitted into each ~aid pipe is a pipe--insert with a diameter substantially lesq than that of the main pipe, so that open ends of the inserted pipe have no contact with closed ends of the pipes, the generatrix of the inserted pipe coming in contact with that of the pipe facing the furnace shell.
The heat removed from the plate is used to heat up the water in the ~ealed pipe. The resultant vapour-water ~ixture rises to the coolant-free end of the pipe wherein the vapour is condensed on the pipe wall, cooled with the coolant flowing through the cooling chamber and circulating within the furnace cooling circuit, and then drainsdown through the inserted pipe. In such a manner the coolant flow is separated into two flows, namely: the vapour-water mixture flow rising to the water-free end of the pipe, and the condensate flow passing down to the portion of the pipe in lOq83~7 contact with the plate. The cooler waC thus enabled to function faultlessly in the conditions of severe heat flowing out of the furnace working space, this being the advantage over the previously described cooler.
However, the hereinabove described cooler is com-plicated in construction due to the difficulty of fitting smaller-diameter pipes into the plate-cooling pipes, the former requiring complex configuration which ressembles that of the latter.
It is therefore an ob~ect of the present invention to improve operating reliabl~ity of a shaft-furnace cooler by means of providing reliable cooling of the cooler plate exposed to heat evoled in metallurgical furnaces.
Another object of the invention is to increase the furnace campaign by means of enhancing operating dura-bility of coolers due to improving the heat resistance of their plates.
Still another object of the invention is to reduce the cooler weight.
SUMMARY OF THE I~VENTION
These and other objects of the invention are accomplished by the provision of a cooler for metallurgical furnaces, comprising a plate adapted to protect the furnace walls against the heat effect and arranged in the way of heat flow, and a means for cooling said plate, made in the form of metal pipes filled with a coolant and sealed at ends thereof, the coolant-containing ends of said pipes being rigidly fixed in the plate while the coolant-free ends thereof are mounted in a cooling chamber, with the coolant . _ 7 -lQn83~7 circulating therethrough, arranged exteriorly of the furnace wall body, and the coolant-free ends of the pipes being slightly above those containing the coolant, wherein, according to the invention, the plate is formed of two layers, namely, a high-heat-conducting layer and a low-heat-conducting layer, the former facing the furnace working space and the latter being presented to the furnace wall body, the interfacial plane of said layers being parallel to the longitudinal axis of said pipes.
Such constructional arrangement of the cooler plate makes it possible to create in each plate-cooling pipe a circulating flow of a definite structure.
Owing to the fact that the plate is made of two layers, with the high-heat-conducting layer facing the furnace working space and the low-heat-conducting one being presented to the furnace wall body, the interfacial plane of said layers running parallel to the longitudinal axis of the plate-cooling pipes, there occurs in each of said pipes a separation of the coolant flow into a vapour-water mixture flow and that of water. The aforesaid separation takes place due to non-uniform heating of the surfaces of said pipes around their periphery. The part of the pipe which faces the furnace working space and in contact with the plate high-heat-conducting layer is heated more than that in contact with the plate layer made of low-heat-conducting material. In the part of the pipe interior passage which is narrowed ~y the overheated walls thereof, there takes place 10~83i~)7 vigorous vapour-forming process accompanied by an ascending flow of vapour-water mixture. In the other part of the pipe interior passage a flow of water unhinderedly passes down, i.e. natural or gravity circulation of coolant is formed within said pipe. Thus, favourable operating conditions are created for the plate-cooling pipes and for the cooler as a whole. Such circulating conditions in the pipes are feasible to maintain within a definite rate of heat flow, required for heating the plate and pipes. Excessive rate of heat flow will upset the aforedescribed structure of the coolant circulation in the pipes, an upwardly moving flow of vapour-water mixture takes up the entire interior space of the pipe, blocking the downward passage of water towards the end of the pipe fixed in the plate, thereby disrupting normal conditions of cooling the plate.
The above-mentioned problem finds its solution in that each pipe is provided with a partition extending short of the closed ends of the pipe and in parallel with the longitudinal axis of the pipe, said partition defining two cavities, one of which is a heat-absorbing cavity facing the high-heat-conducting layer, the partition plane being substantially coincident with the interfacial plane of the two plate layers.
Such an arrangement of the partitions in the cooler plate-cooling pipes is required to enable mechanical separation of the ascending flow of vapour-water mixture formed in the part of the pipe adjacent to the high-heat-conducting layer, and the downwardly passing flow of water formed of _ g _ ~0"83~7 the condensed vapour. Thus, the upwardly moving flow will not impede the downward passage of water to the pipe end fixed in the plate. This allows for reliable cooling of the plate and affords protection to the furnace wall body against the heat effect.
Since the pipes with partitions therein are simple to manufacture, the latter are secured in the pipe longitudi-nal central plane. Such an arrangement of the partition is the best possible, with the latter being equal in width to in diameter of the pipe into which it is inserted.
The passageway of the pipe is thus divided by the partition into cavities equal in cross section, which, however, is undesirable from the point of view of hydraulic resistance to the ascending flow of vapour-water mixture in the cavity adjacent the high-heat-conducting layer of the plate. When the heat load acting on the plate and pipes becomes excessive, a great amount of vapour is formed in the cavity adjacent the high-heat-conducting layer, said cavity being small enough in 10~8307 in cross-section to enable the escape of vapor. This being the case, a directed coolant circulation in the pipes is dis-rupted and the cooling of plate is deteriorated.
The above disadvantage is eliminated by way of dis-placing the partition plane from the longitudinal central plane of the pipe towards the furnace wall body by 0.1 to 0.3 of the pipe inside diameter.
Such mounting of the partitions in the plate-cooling pipes brings about an increase in the cross-sectional area of the pipe cavity adjacent to the high heat-conducting layer of the plate, i.e., hydraulic resistance to the ascending flow of vapor-water mixture is reduced. This, in turn, results in reliable circulation of coolant in the pipes.
Such an arrangement of the partitions makes for the removal of specific heat loads on the order of 30X106 c2al m h through the cross-sectional area of the pipe cavity adjacent to the high heat-conducting layer without upsetting the coolant circulation in the pipe.
The high heat-conducting layer of the two-layer plate is preferably manufactured from such material as heat-resistant iron, and the low heat-conducting layer from heat-resistant concrete. Since specific weight of concrete is considerably less than that of cast iron, the cooler plate is reduced in weight.
With a purpose of enhancing heat resistance of the high heat-conducting layer, the latter is formed of individual bars which are mounted on the pipes for free movement during thermal expansion along the axes of the pipes.
Due to the fact that t~e cooler in accordance with the invention is constructed so that the plate thereof consists of two layers, namely, a high heat-conducting layer and a low heat-conducting one, and the pipes are provided with partitions, it became possible to considerably expand the operating range of heat loads which fail to affect the cooler plate being under effective cooling protection of the pipes, and thus to enhancing heat resistance of the cooler. It has been found feasible to make use of the pipes for cooling purposes of metallurgical installations, which are sealed at their ends and filled with a coolant, the ends of said pipes at one side being rigidly fixed in the plate and extending at the other side beyond the plate and through the furnace wall body into a cooling chamber to be fixed therein. This allows for removing severe heat fluxes which arise in individual coolers independently of moderate heat fluxes; it also precludes the penetration of water into the furnace working space in case of any damage to a pipe; and makes it possible to reduce the weight of coolers adapted for use on metallurgical installations.
These and other objects and features of the invention will become more apparent from a specific embodiment thereof, taken in conjunction with the accompanying drawings. In the drawings:
10~83~7 Fig. 1 is a longitudinal cross-sectional view of a cooler according to the invention;
Fig. 2 is a cross-section taken along line II-II, a low-heat-conducting layer is not shown, Fig. 3 is a cross-section taken along line III-III
of Fig. 2, and Fig. 4 is a cross-section taken along line IU-IV, wherein a partition is constructed in accordarce with claim 6.
DESCRIPTION OF THE PREFERRED EMBOD~MENT
_ _ .
In the embodiment, a cooler for a blast furnace comprises a two-layer plate l(see Fig. 1), of which layer
The present invention relates to cooling arrangements for protecting the walls of metallurgical furnaces from heat, and more particularly to shaft-furnace coolers~
The invention can be advantageously applied for the protection of blast-furnace shells.
Because of elevated temperatures created in the working space of a blast furnace, the shell-thereof is subjected to severe heat. Therefore, special arrangements are called for to insure mechanical strength of such shells and protect them from heat loads. The arrangements in question are plate coolers which are usually mounted on the furnace shell at the side of the furnace working space.
It is modern practice to intensify the blast-furnace process by raising the blast temperature, increasing the amount of oxygen contained in the blast, or else by building up pressure in the furnace space. The above factors are detrimental to the operation of heat-protecting arrangements, placing more stringent requirements upon their ability to resist heat.
There are known in the art plate coolers which comprise a cast-iron plate with built-in steel pipes whose open ends extend beyond the plate and through the furnace shell. The pipes are connected through said ends with the furnace cooling circuit through which circulates a coolant, such as industrial or chemically treated water, or vapour-water mixture.
~0~83~)7 In the course of the blast-furnace operation, the plate is e~posed to heat loads which vary timewise. As a result, the plate tends to change its geometrical dimensions, expanding and contracting. The plate expansion and shrinkage adversely affect the pipes which are rigidly connected therewith. The process of manufacturing coolers is such that it causes embrittlement of steel pipes which are subjected to carbonization in the process of casting molten iron therein. The ends of the pipes extending through the furnace shell are usually we~lided thereto. With the iron plate acting upon said pipes, there creates therein periodi-cally variable pressures which bring about their destruction.
As a result, the coolant passing from the furnace cooling circuit penetrates through the damaged pipe into the furnace working space. This calls for higher fuel input per unit of production because of the heat losses require~or the evaporation of the escaped coolant. In some cases, the penetration of considerable amount of coolant to the furnace may even disrupt the furnace operating process.
At present, for lack of reliable and prompt trouble-shooting techniques, it takes considerable time and human effort to spot and disconnect the damaged pipe. The atten-ding personnel involved in such operation are compelled to work in the conditions of severe gas contamination and high temperatures.
10"83~7 It is deemed necessary to point out still another dis-advantage of the hereinbefore described coolers. There is pro-vided in the furnace cooling circuit, with a plurality of coolers being connected thereto, gravity circulation of the coolant. This type of the coolant circulation depends for its rate on the average heat load acting on the coolers. With the lining being broken away from the surface of the cooler plate, the latter is exposed to severe heating which can be eliminated only by increasing the rate of vapor-water mixture circulation through the pipes intended for cooling the plate. As mentioned above, however, the rate of circulation depends solely on the average heat load acting on the group of coolers, which practi-cally remains unaltered. Therefore, the increased amount of heat effecting a separate plate results in greater amount of vapor in the pipes cooling this plate, which, in turn, causes its overheating and fusion.
A construction in accordance with the present invention includes a cooler for a shaft furnace comprising a plate adapted to protect the furnace wall body against the effect of heat flux to which it is exposed and formed of two layers, a high heat-conducting layer facing the furnace working space and a low heat-conducting one presented to the furnace wall, a means for cooling said plate, made in the form of metal pipes partially filled with a coolant and sealed at the ends thereof, the longi-tudinal axis of said pipes being parallel to the interfacial plane of said layers, a cooling chamber arranged exteriorly of the furnace wall body and having a coolant circulating there-through, ends of said pipes partially filled with a coolant _ 4 -10~83~7 being rigidly connected to said plate, ends of said pipes free from coolant, arranged slightly above those filled therewith and mounted in said cooling chamber.
In other words, in order to improve the cooling of the cooler plate by a sudden increase of the flow rate of heat affecting said cooler and eliminating the possibility of the water penetration into a metallurgical furnace, there has been developed a cooler comprising a plate with pipes whose ends at one side thereof are built into said plate, filled with a coolant and sealed. The other ends of the pipes, which are mounted higher than those filled with water, extend beyond the plate and pass through the furnace shell into a cooling chamber wherein they - 4a -10"83~7 are fixed. Circulating in the cooling chamber is a coolant.
The cooling chamber is arranged exteriorly of the furnace and connected to the cooling circuit thereof.
The improved cooling of the plate of each separate cooler has been accomplished by way of sealing the ends of the cooler plate pipes, whereby each pipe is provided with its own circuit wherein the vapour-water mixture circulation is determined by the heat loads acting on such circuit. The rate of vapour-water mixture circulation in the plate-cooling pipes increases with the heat load acting on the plate, thereby providing for reliab~e cooling of said plate.
The use of such cooler practically eliminates the coolant penetration to the furnace in case of damage of the sealed pipe, since there is but a negligible amount of coolant contained therein, with the furnace cooling circuit, wherein circulates water, being separated from the interior of the damaged pipe by the wall of the latter. This being the cooler construction,the pipe is surrounded with the cast-iron plate, having therefore, its entire surface exposed to heat. It happens that certain heat flows cause abundant formation of vapour in the part of the pipe which is fixed in the plate, and the condensate, formed in the free part of the pipe due to condensation of vapour passing there~nto through a cooling chamber, is prevented from descending to the lower part of the pipe. Thus, the water from the part of the pipe fixed in the plate is rushed to the upper part of the pipe. This results in the overheating of the pipe and 10"8307 plate walls because of the absence of the heat outlet leading to the furnace cooling circuit, and the destruction of the cooler thus becomes in~vitable.
To eliminate the above-mentioned disadvantage, there has been proposed a cooler for a metallurgical shaft furnace, comprising a plate with built-in pipes whose ends at one side thereof are filled with a coolant and sealed.
Ihe other ends of said pipes are disposed above tho~e filled with the coolant and extend beyond the plate and through the furnace shell into a cooling chamber to be fixed therein`, said chamber being connected to the furnace cooling circuit with a coolant circulating therethrough. Fitted into each ~aid pipe is a pipe--insert with a diameter substantially lesq than that of the main pipe, so that open ends of the inserted pipe have no contact with closed ends of the pipes, the generatrix of the inserted pipe coming in contact with that of the pipe facing the furnace shell.
The heat removed from the plate is used to heat up the water in the ~ealed pipe. The resultant vapour-water ~ixture rises to the coolant-free end of the pipe wherein the vapour is condensed on the pipe wall, cooled with the coolant flowing through the cooling chamber and circulating within the furnace cooling circuit, and then drainsdown through the inserted pipe. In such a manner the coolant flow is separated into two flows, namely: the vapour-water mixture flow rising to the water-free end of the pipe, and the condensate flow passing down to the portion of the pipe in lOq83~7 contact with the plate. The cooler waC thus enabled to function faultlessly in the conditions of severe heat flowing out of the furnace working space, this being the advantage over the previously described cooler.
However, the hereinabove described cooler is com-plicated in construction due to the difficulty of fitting smaller-diameter pipes into the plate-cooling pipes, the former requiring complex configuration which ressembles that of the latter.
It is therefore an ob~ect of the present invention to improve operating reliabl~ity of a shaft-furnace cooler by means of providing reliable cooling of the cooler plate exposed to heat evoled in metallurgical furnaces.
Another object of the invention is to increase the furnace campaign by means of enhancing operating dura-bility of coolers due to improving the heat resistance of their plates.
Still another object of the invention is to reduce the cooler weight.
SUMMARY OF THE I~VENTION
These and other objects of the invention are accomplished by the provision of a cooler for metallurgical furnaces, comprising a plate adapted to protect the furnace walls against the heat effect and arranged in the way of heat flow, and a means for cooling said plate, made in the form of metal pipes filled with a coolant and sealed at ends thereof, the coolant-containing ends of said pipes being rigidly fixed in the plate while the coolant-free ends thereof are mounted in a cooling chamber, with the coolant . _ 7 -lQn83~7 circulating therethrough, arranged exteriorly of the furnace wall body, and the coolant-free ends of the pipes being slightly above those containing the coolant, wherein, according to the invention, the plate is formed of two layers, namely, a high-heat-conducting layer and a low-heat-conducting layer, the former facing the furnace working space and the latter being presented to the furnace wall body, the interfacial plane of said layers being parallel to the longitudinal axis of said pipes.
Such constructional arrangement of the cooler plate makes it possible to create in each plate-cooling pipe a circulating flow of a definite structure.
Owing to the fact that the plate is made of two layers, with the high-heat-conducting layer facing the furnace working space and the low-heat-conducting one being presented to the furnace wall body, the interfacial plane of said layers running parallel to the longitudinal axis of the plate-cooling pipes, there occurs in each of said pipes a separation of the coolant flow into a vapour-water mixture flow and that of water. The aforesaid separation takes place due to non-uniform heating of the surfaces of said pipes around their periphery. The part of the pipe which faces the furnace working space and in contact with the plate high-heat-conducting layer is heated more than that in contact with the plate layer made of low-heat-conducting material. In the part of the pipe interior passage which is narrowed ~y the overheated walls thereof, there takes place 10~83i~)7 vigorous vapour-forming process accompanied by an ascending flow of vapour-water mixture. In the other part of the pipe interior passage a flow of water unhinderedly passes down, i.e. natural or gravity circulation of coolant is formed within said pipe. Thus, favourable operating conditions are created for the plate-cooling pipes and for the cooler as a whole. Such circulating conditions in the pipes are feasible to maintain within a definite rate of heat flow, required for heating the plate and pipes. Excessive rate of heat flow will upset the aforedescribed structure of the coolant circulation in the pipes, an upwardly moving flow of vapour-water mixture takes up the entire interior space of the pipe, blocking the downward passage of water towards the end of the pipe fixed in the plate, thereby disrupting normal conditions of cooling the plate.
The above-mentioned problem finds its solution in that each pipe is provided with a partition extending short of the closed ends of the pipe and in parallel with the longitudinal axis of the pipe, said partition defining two cavities, one of which is a heat-absorbing cavity facing the high-heat-conducting layer, the partition plane being substantially coincident with the interfacial plane of the two plate layers.
Such an arrangement of the partitions in the cooler plate-cooling pipes is required to enable mechanical separation of the ascending flow of vapour-water mixture formed in the part of the pipe adjacent to the high-heat-conducting layer, and the downwardly passing flow of water formed of _ g _ ~0"83~7 the condensed vapour. Thus, the upwardly moving flow will not impede the downward passage of water to the pipe end fixed in the plate. This allows for reliable cooling of the plate and affords protection to the furnace wall body against the heat effect.
Since the pipes with partitions therein are simple to manufacture, the latter are secured in the pipe longitudi-nal central plane. Such an arrangement of the partition is the best possible, with the latter being equal in width to in diameter of the pipe into which it is inserted.
The passageway of the pipe is thus divided by the partition into cavities equal in cross section, which, however, is undesirable from the point of view of hydraulic resistance to the ascending flow of vapour-water mixture in the cavity adjacent the high-heat-conducting layer of the plate. When the heat load acting on the plate and pipes becomes excessive, a great amount of vapour is formed in the cavity adjacent the high-heat-conducting layer, said cavity being small enough in 10~8307 in cross-section to enable the escape of vapor. This being the case, a directed coolant circulation in the pipes is dis-rupted and the cooling of plate is deteriorated.
The above disadvantage is eliminated by way of dis-placing the partition plane from the longitudinal central plane of the pipe towards the furnace wall body by 0.1 to 0.3 of the pipe inside diameter.
Such mounting of the partitions in the plate-cooling pipes brings about an increase in the cross-sectional area of the pipe cavity adjacent to the high heat-conducting layer of the plate, i.e., hydraulic resistance to the ascending flow of vapor-water mixture is reduced. This, in turn, results in reliable circulation of coolant in the pipes.
Such an arrangement of the partitions makes for the removal of specific heat loads on the order of 30X106 c2al m h through the cross-sectional area of the pipe cavity adjacent to the high heat-conducting layer without upsetting the coolant circulation in the pipe.
The high heat-conducting layer of the two-layer plate is preferably manufactured from such material as heat-resistant iron, and the low heat-conducting layer from heat-resistant concrete. Since specific weight of concrete is considerably less than that of cast iron, the cooler plate is reduced in weight.
With a purpose of enhancing heat resistance of the high heat-conducting layer, the latter is formed of individual bars which are mounted on the pipes for free movement during thermal expansion along the axes of the pipes.
Due to the fact that t~e cooler in accordance with the invention is constructed so that the plate thereof consists of two layers, namely, a high heat-conducting layer and a low heat-conducting one, and the pipes are provided with partitions, it became possible to considerably expand the operating range of heat loads which fail to affect the cooler plate being under effective cooling protection of the pipes, and thus to enhancing heat resistance of the cooler. It has been found feasible to make use of the pipes for cooling purposes of metallurgical installations, which are sealed at their ends and filled with a coolant, the ends of said pipes at one side being rigidly fixed in the plate and extending at the other side beyond the plate and through the furnace wall body into a cooling chamber to be fixed therein. This allows for removing severe heat fluxes which arise in individual coolers independently of moderate heat fluxes; it also precludes the penetration of water into the furnace working space in case of any damage to a pipe; and makes it possible to reduce the weight of coolers adapted for use on metallurgical installations.
These and other objects and features of the invention will become more apparent from a specific embodiment thereof, taken in conjunction with the accompanying drawings. In the drawings:
10~83~7 Fig. 1 is a longitudinal cross-sectional view of a cooler according to the invention;
Fig. 2 is a cross-section taken along line II-II, a low-heat-conducting layer is not shown, Fig. 3 is a cross-section taken along line III-III
of Fig. 2, and Fig. 4 is a cross-section taken along line IU-IV, wherein a partition is constructed in accordarce with claim 6.
DESCRIPTION OF THE PREFERRED EMBOD~MENT
_ _ .
In the embodiment, a cooler for a blast furnace comprises a two-layer plate l(see Fig. 1), of which layer
2 facing the furnace inner space is formed of individùal cast-iron bars 3 extending horizontally for a length greater than vertically, the other layer 4 thereof being presented to a furnace wall 5 and formed of heat-resistant concrete.
The cooler plate 1 likewise incorporates at least two pipes 6, such as shown in Fig. 2, which pipes are partially filled with a coolant and sealed at the ends thereof with plugs 7, such as shown in Fig. 1, said pipes each being provided with a partition 8 extending short of the plugs 7. The coolant-filled end of the pipe 6 is mounted in the plate 1, the coolant-free end of said pipe 6 being mounted within 2 cooling chamber 9 arranged exteriorly of the furnace wall 5 and con-nected to the furnace cooling circuit (not shown~.
The partition 8 divides the interior of the pipe 6 into two cavities, of which a heat-absorbing cavity 10 is adjacent to the high heat-conducting layer 2, the other _ 13 ~
10~83~7 cavity 11 being adjacent to the low heat-conducting layer 4 formed of heat-resistant concrete. Provided on the surface of each bar 3, presented to the furnace wall 5, is a recess such as shown at 12 in Fig. 3, adapted to receive the pipes 6 therein: the surfaces of said bars presented to the furnace working space being formed with ribs 13 such as shown in Fig. 1. The pipes 6 are interconnected by means of cleats 14, shown in Fig. 2. The interconnected pipes 6 are accom-modated in the recesses 12 fitted in the bars 3. Each of the bars 3 is fixed by means of pins 15, cast-in in the interspaces between the recesses 12, on the pipes 6 with the aid of plates, such as plate springs 16 which are secured on said pipes 6 by screw nuts 17. To enable mounting the plate 1 on the furnace wall body 5 the pipes 6 have welded thereto lugs 18, such as shown in Fig. 3, fitted with threaded holes 19 adapted to receive studs 20 therein. The described cooler is secured on the furnace wall body 5 by means of the studs 20 and screw nuts 21. All the coolers are mounted on the furnace wall body 5 so that a gap 22 is provided for a heat-insulating material to be placed therein, the size of saidgap being determined by the height of the lug 18. To ~aci-litate heat transfer from the bars 3 to the pipes 6, the recesses 12 accommodate therein a layer 23 of heat-conducting material.
The number of the bars 3 which make up the metal layer 2 of the plate 1 is determi-ned by the cooler height and width parameters so that the height-width ratio of the 10~83~)7 bar 3 be within the range of 2 to 4, respectively.
The number of the pipes 6 provided in the cooleris determined by the width of the plate 1, as well as by the heat load acting on the cooler used in a given metallurgical installation.
The diameter of the pipe 6 is selected in accordance with a rigidity of the cooler construction and heat loads acting thereupon.
The provision of the partition 8 in the pipe 6, as well as its arrangement therein, is governed by heat loads acting on the cooler and, consequently, by the heat loads transferred through the cross-section of the pipe 6. The cast-iron bars 3 of each cooler are heated with the heat of the furnace working space, transferring the absorbed heat through the heat-conducting layer 23 to the walls of the cooling pipes 6. The transferred heat causes boiling of water in the heat-abSorbing cavities 10 of the pipes 6, with the resultant ascending flow of vapour-water mixture being formed in each of said cavities. The heat passing up to the pipes 6 from the side of the concrete-made layer 4 is considerably less in amount due to lower heat conductivity of heat-resistant concrete as compared to that of metal. Therefore, the hy-draulic resistance, created in the cavity 11 of the pipe 6, to the downwardly passing flow of condensate formed in the coolant-free end of the pipe 6 cooled by the coolant flowing through the chamber 9, is very small. Thus a directed circula-tion of the vapour-water mixture and water originates in the ~0~83'~)7 interior of the pipe 6, i.e. in the cavity 10 of the pipe 6 a flow of vapour-water mixture rises to the fluid-free end of the pipe 6 wherein vapour is separated from water to be thereby condensed, the water draining down through the cavity 11 to the lower end of the pipe 6. In this manner a reliable cooling is provided for the walls of the pipes 6 and bars 3, and the cooler thus fulfils its function aimed at affording protection to the walls of furnaces from over-heating and destruction.
When subjected to heating the bars 3 tend to increase in dimensions, freely elongating in the direction parallel to the axes of the pipes 6, with the fixture elements 15, 16 and 17 permitting such elongation~ As a result, the dis-placement of the bars 3 cause no mechanical strains in the pipes 6.
With heat fluxes passing up at a higher rate, which fluxes are removed through the cavity 10 of the pipe 6, it is advisable to install the partition 24, such as shown in Fig. 4, in the plane offset from the longitudinal central plane of the pipe towards the layer 4 by 0.1 to 0.3 of the pipe inside diameter, which increases the cross-sectional area of the cavity 10 and, consequently, decreases hydraulic resistance to the ascending flow of vapour-water mixture in the cavity 10.
Therefore, the cooler construction according to the invention makes it possible to improve operational reliability of the cooling system utilized on metallurgical 10~8307 installations due to enhancing the heat resistance of cooler plates, - provides for autonomous operation of each cooling pipe, which permits of removing from the plate being cooled vigorous heat fluxes forming in various places within the furnace, - increases campaign of metallurgical furnaces, - brings down to minimum emergency situations due to destruction of the furnace wallq, - prevents penetration of water to the furnace working space, - reduces the cooler weight by 1.5 time.
The cooler plate 1 likewise incorporates at least two pipes 6, such as shown in Fig. 2, which pipes are partially filled with a coolant and sealed at the ends thereof with plugs 7, such as shown in Fig. 1, said pipes each being provided with a partition 8 extending short of the plugs 7. The coolant-filled end of the pipe 6 is mounted in the plate 1, the coolant-free end of said pipe 6 being mounted within 2 cooling chamber 9 arranged exteriorly of the furnace wall 5 and con-nected to the furnace cooling circuit (not shown~.
The partition 8 divides the interior of the pipe 6 into two cavities, of which a heat-absorbing cavity 10 is adjacent to the high heat-conducting layer 2, the other _ 13 ~
10~83~7 cavity 11 being adjacent to the low heat-conducting layer 4 formed of heat-resistant concrete. Provided on the surface of each bar 3, presented to the furnace wall 5, is a recess such as shown at 12 in Fig. 3, adapted to receive the pipes 6 therein: the surfaces of said bars presented to the furnace working space being formed with ribs 13 such as shown in Fig. 1. The pipes 6 are interconnected by means of cleats 14, shown in Fig. 2. The interconnected pipes 6 are accom-modated in the recesses 12 fitted in the bars 3. Each of the bars 3 is fixed by means of pins 15, cast-in in the interspaces between the recesses 12, on the pipes 6 with the aid of plates, such as plate springs 16 which are secured on said pipes 6 by screw nuts 17. To enable mounting the plate 1 on the furnace wall body 5 the pipes 6 have welded thereto lugs 18, such as shown in Fig. 3, fitted with threaded holes 19 adapted to receive studs 20 therein. The described cooler is secured on the furnace wall body 5 by means of the studs 20 and screw nuts 21. All the coolers are mounted on the furnace wall body 5 so that a gap 22 is provided for a heat-insulating material to be placed therein, the size of saidgap being determined by the height of the lug 18. To ~aci-litate heat transfer from the bars 3 to the pipes 6, the recesses 12 accommodate therein a layer 23 of heat-conducting material.
The number of the bars 3 which make up the metal layer 2 of the plate 1 is determi-ned by the cooler height and width parameters so that the height-width ratio of the 10~83~)7 bar 3 be within the range of 2 to 4, respectively.
The number of the pipes 6 provided in the cooleris determined by the width of the plate 1, as well as by the heat load acting on the cooler used in a given metallurgical installation.
The diameter of the pipe 6 is selected in accordance with a rigidity of the cooler construction and heat loads acting thereupon.
The provision of the partition 8 in the pipe 6, as well as its arrangement therein, is governed by heat loads acting on the cooler and, consequently, by the heat loads transferred through the cross-section of the pipe 6. The cast-iron bars 3 of each cooler are heated with the heat of the furnace working space, transferring the absorbed heat through the heat-conducting layer 23 to the walls of the cooling pipes 6. The transferred heat causes boiling of water in the heat-abSorbing cavities 10 of the pipes 6, with the resultant ascending flow of vapour-water mixture being formed in each of said cavities. The heat passing up to the pipes 6 from the side of the concrete-made layer 4 is considerably less in amount due to lower heat conductivity of heat-resistant concrete as compared to that of metal. Therefore, the hy-draulic resistance, created in the cavity 11 of the pipe 6, to the downwardly passing flow of condensate formed in the coolant-free end of the pipe 6 cooled by the coolant flowing through the chamber 9, is very small. Thus a directed circula-tion of the vapour-water mixture and water originates in the ~0~83'~)7 interior of the pipe 6, i.e. in the cavity 10 of the pipe 6 a flow of vapour-water mixture rises to the fluid-free end of the pipe 6 wherein vapour is separated from water to be thereby condensed, the water draining down through the cavity 11 to the lower end of the pipe 6. In this manner a reliable cooling is provided for the walls of the pipes 6 and bars 3, and the cooler thus fulfils its function aimed at affording protection to the walls of furnaces from over-heating and destruction.
When subjected to heating the bars 3 tend to increase in dimensions, freely elongating in the direction parallel to the axes of the pipes 6, with the fixture elements 15, 16 and 17 permitting such elongation~ As a result, the dis-placement of the bars 3 cause no mechanical strains in the pipes 6.
With heat fluxes passing up at a higher rate, which fluxes are removed through the cavity 10 of the pipe 6, it is advisable to install the partition 24, such as shown in Fig. 4, in the plane offset from the longitudinal central plane of the pipe towards the layer 4 by 0.1 to 0.3 of the pipe inside diameter, which increases the cross-sectional area of the cavity 10 and, consequently, decreases hydraulic resistance to the ascending flow of vapour-water mixture in the cavity 10.
Therefore, the cooler construction according to the invention makes it possible to improve operational reliability of the cooling system utilized on metallurgical 10~8307 installations due to enhancing the heat resistance of cooler plates, - provides for autonomous operation of each cooling pipe, which permits of removing from the plate being cooled vigorous heat fluxes forming in various places within the furnace, - increases campaign of metallurgical furnaces, - brings down to minimum emergency situations due to destruction of the furnace wallq, - prevents penetration of water to the furnace working space, - reduces the cooler weight by 1.5 time.
Claims (6)
1. A cooler for a shaft furnace, comprising: a plate adapted to protect the furnace wall body against the effect of heat flux to which it is exposed and formed of two layers, a high heat-conducting layer facing the furnace working space and a low heat-conducting one presented to the furnace wall; a means for cooling said plate, made in the form of metal pipes partially filled with a coolant and sealed at the ends thereof, the longitudinal axis of said pipes being parallel to the inter-facial plane of said layers; a cooling chamber arranged exter-iorly of the furnace wall body and having a coolant circulating therethrough; ends of said pipes partially filled with a coolant being rigidly connected to said plate; ends of said pipes free from coolant, arranged slightly above those filled therewith and mounted in said cooling chamber.
2. A cooler as claimed in claim 1, comprising: individual bars making up said heat-conducting layer of said plate, each of said bars having a length dimension in a horizontal direction greater than the height dimension in a vertical direction;
recesses adapted to accommodate said pipes and formed on the surfaces of said bars facing the furnace wall; a layer of a heat-conducting material placed in said recesses; elements for fixing each of said bars to said pipes, said elements being fitted in the interspaces between said recesses; members for securing said pipes to the furnace wall, said members being welded to said pipes.
recesses adapted to accommodate said pipes and formed on the surfaces of said bars facing the furnace wall; a layer of a heat-conducting material placed in said recesses; elements for fixing each of said bars to said pipes, said elements being fitted in the interspaces between said recesses; members for securing said pipes to the furnace wall, said members being welded to said pipes.
3. A cooler as claimed in claim 1, wherein heat-resistant iron is used as the material for said high heat-conducting layer, heat-resistant concrete being used for said low heat-conducting layer.
4. A cooler as claimed in claim 1, comprising: partitions each being mounted in each of said pipes and extending short of the end of said pipe and defining two cavities, one of which being heat-absorbing cavity adjacent to said high heat-conducting layer, the plane of said partition being substantially coincident with said interfacial plane of said layers.
5. A cooler as claimed in claim 4, wherein each plane of each said partition is coincident with the longitudinal central plane of each said pipe.
6. A cooler as claimed in claim 4, wherein said plane of each said partition is offset from the longitudinal axis of each said pipe towards the furnace wall by 0.1 to 0.3 of the inside diameter of said pipe.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA294,995A CA1098307A (en) | 1978-01-16 | 1978-01-16 | Cooler for shaft furnace |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA294,995A CA1098307A (en) | 1978-01-16 | 1978-01-16 | Cooler for shaft furnace |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1098307A true CA1098307A (en) | 1981-03-31 |
Family
ID=4110547
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA294,995A Expired CA1098307A (en) | 1978-01-16 | 1978-01-16 | Cooler for shaft furnace |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1098307A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113234875A (en) * | 2021-06-19 | 2021-08-10 | 山东天铭重工科技股份有限公司 | Sweating type cast iron cooling wall of iron making blast furnace |
-
1978
- 1978-01-16 CA CA294,995A patent/CA1098307A/en not_active Expired
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113234875A (en) * | 2021-06-19 | 2021-08-10 | 山东天铭重工科技股份有限公司 | Sweating type cast iron cooling wall of iron making blast furnace |
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| MKEX | Expiry |