JPH08501864A - Thermal process in which the charge is rotated along the longitudinal axis - Google Patents

Abstract

(57) Summary In particular, a furnace (5a, 5b) is disclosed for heat treating porcelain articles such as tubes (85a, 85b) or tiles, although not wholly. Prior art furnaces have several problems. For example, the length of the furnace makes the furnace impractical for large diameter tubes and is limited only to heat treatment of tubes of a certain diameter, and heat exchange is properly done between the lower and upper zones. Not done Accordingly, the present invention provides a dry / pretropical zone (10a, 10b), a combustion zone (25a, 25b), a cooling zone (40a, 40b), and one or more tubes through at least one of the zones. A furnace (5a, 5b) for heat treating tubes (85a, 85b), comprising a conveyor device for transporting one or more supporting devices (80a, 95a, 80b, 95b) each supporting (85a, 85b). In use, each tube (85a, 85b) is supported on a respective support device (80a, 95a, 80b, 95b) at approximately right angles to the direction of transfer, and each support device (80a , 95a, 80b, 95b) further comprises a device (100a, 100b) for rotating each tube (85a, 85b) supported by it along the length of the respective tube.

Description

Description: BACKGROUND OF THE INVENTION The present invention relates to a thermal process for a furnace, and in particular, but not entirely, for porcelain products such as tubes or tiles. It relates to a furnace for heat treatment. A furnace in which the tubes are rotated in a hot zone to maintain roundness and ensure uniform heating is disclosed in GB2021743 (Hepworth). A furnace having upper and lower levels and a chain rotatably moving a tube of the same diameter along a path containing both levels is disclosed in U.S. Pat. No. 4,628,615 (Belhayden). The devices disclosed in the above-mentioned patent specifications have several problems. For example, the furnace disclosed in British Patent No. 1021743 is very long and therefore impractical for large diameter tubes. The furnace disclosed in U.S. Pat. No. 4,628,615 has the problem that it is only suitable for heat treatment of tubes of a certain diameter. Also, U.S. Pat. No. 4,628,615 has the problem that the temperature of the solubilization zone is cycled between the highest and lowest temperature and that heat exchange does not take place properly between the lower and upper zones. ing. Accordingly, it is an object of the present invention to eliminate or mitigate at least some of the above mentioned drawbacks. SUMMARY OF THE INVENTION A first aspect of the invention is a dry / pretropical zone, a combustion zone, a cooling zone, and one or more tubes each supporting one or more tubes through at least one of the zones. And a conveyor device for transferring the supporting device of (1), and a furnace for heat-treating the pipe is provided. In use, each tube is supported on its respective support device at approximately right angles to the direction of transport, and each support device rotates each tube supported thereon along the length of the respective tube. It further has a device for The support device in at least one swath may include a wheeled trolley. The support device in at least one swath may include a walking frame or beam. Suitably, adjacent zones are separated from each other by a transfer zone having a device for transferring the tube from the support device used in one band to the support device used in the next band. To be done. The support devices used in the dry / pretropical and cooling zones may be made of mild steel, and the device that rotates each tube is probably made of stainless steel. The support device used in the combustion zone may be made of mild steel, and the device that rotates each tube is probably made of silicon carbide. The support device used in the combustion zone may have insulating plates at both ends to reduce heat loss. The combustion zone may have a lower portion and an upper portion through which the support device passes in opposite directions so as to provide heat exchange between the lower and upper portions. The combustion zone may include an upper rapid heating section and a lower solubilizing and quenching section. Similarly, the drying / pre-tropics may be provided above the cooling zones to provide heat exchange between the cooling zones and the drying / pre-tropics. The dry / pretropical zone may include a dry portion and a preheat / mineralized portion. According to a second aspect of the invention, there is provided a support device for use in a furnace, said support device being capable of supporting and transporting one or more tubes through said strip, each tube being in its longitudinal direction. It also has a device that rotates along it. According to a third aspect of the invention, the tubes are placed on a support device having a device for rotating each tube supported thereon along the longitudinal direction of the respective tube, the drying / preheating zone, the combustion zone, A method of heat treating tubes, wherein each support apparatus is transported by a conveyor apparatus through at least one zone of a furnace including a cooling zone and each tube is supported on the support apparatus at substantially right angles to the direction of transfer. Will be provided. According to a fourth aspect of the present invention there is provided a furnace for heat treating material comprising a drying / pretropical zone, a combustion zone, a cooling zone and a conveyor device for transferring one or more materials through each zone. Adjacent zones are then separated from each other by a transition zone having a device for transferring the material from one zone to the next. Suitably, one or more materials are supported on a support device, which can be transported by a conveyor device. The combustion zone may have a lower portion and an upper portion through which the support device passes in opposite directions to provide heat exchange between the lower and upper portions. The combustion zone may include an upper rapid heating section and a lower solubilizing and quenching section. Similarly, the dry / pretropical zone may be provided above the cooling zone to provide heat exchange between the cool zone and the dry / pretropical zone. The dry / pretropical zone may include a dry portion and a preheat / mineralized portion. According to a fifth aspect of the present invention, the material is fed through the dry / pretropical zone, the material is transferred to the combustion zone via the first transition zone, the material is fed through the combustion zone and then the cooling zone via the second transition zone. A method of heat treating a material is provided that includes transferring the material to. DESCRIPTION OF THE DRAWINGS An embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: FIG. 1 is a simplified heat treatment schedule for a porcelain tube to be melted, FIG. Schematic side elevation view of the first embodiment of the furnace, FIG. 3 Side elevation view of the furnace according to the first embodiment of the invention shown in FIG. 2, FIG. 4 Cross section of the furnace of FIG. FIG. 5 is an end elevational view of a section of the cold zone of the furnace of FIG. 3 at an enlarged scale, and FIG. 6 is an end elevation view of the transition zone of the furnace of FIG. 7 is an end elevational view of a section of the combustion zone of the furnace of FIG. 3 against an enlarged scale of FIG. 7, FIG. 8 is a schematic side elevational view of a second embodiment of the furnace according to the invention. Plan view, FIG. 9 FIG. 8 A plan elevation view of a furnace according to a second embodiment of the invention, FIG. 10 Drying / pre-tempering and disconnection of cooling zones of the furnace of FIG. 11 is a side elevational view of FIG. 11, FIG. 11 is an end elevational view in section of the furnace of FIG. 9 to an enlarged scale of the drying / pretropics and cooling zones, and FIG. 12 is an expansion of the combustion zone of the furnace of FIG. FIG. 13 is a side elevational view of a section to a reduced scale, FIG. 13 is an end elevational view of a combustion zone of the furnace of FIG. 9 to an enlarged scale, and FIG. 14 is a high temperature walking frame of the furnace of FIG. FIG. 15 is an end view of the associated transmission, FIG. 15 is a side view to an enlarged scale of the rollers of the walking frame of the combustion zone of the furnace of FIG. 9 showing the different dimensions of the loadable tubes. Description of the First Embodiment Referring to FIG. 1, a simplified heat treatment schedule for a porcelain tube is shown. As can be seen from FIG. 1, the schedule includes a high temperature process involving combustion, sintering and quenching steps that require high temperature engineering materials, and a more conventional engineering material before and after the high temperature process, respectively. Can be used and may be subdivided into low temperature processes including drying / preheating and cooling steps. Referring to FIGS. 2 to 7, a drying / pre-tropical zone 10a having input and discharge ends 15a, 20a, a combustion zone 25a having input and discharge ends 30a, 35a, and also input and discharge. A first embodiment of a furnace according to the invention is provided, generally designated by 5a, including a cooling zone 40a having ends 45a, 50a. The drying / preheating zone 10a is divided into a drying portion 55a in which the temperature is gradually raised from about 100 ° C. to 200 ° C. and a preheating / mineralization portion 60a in which the temperature is gradually raised from about 200 ° C. to 750 ° C. A cooling zone 40a is installed below the drying / pretropical zone 10a to provide heat exchange therebetween, as is usual in half tunnel furnaces. In the cooling zone 40a, the temperature is gradually lowered from about 650 ° C to 100 ° C. Combustion zone 25a includes an upper rapid heating or burning portion 65a and a lower solubilizing (or sintering) and rapid cooling (or quenching) portion 70a, 75a. The solubilizing and quenching portions 70a, 75a are located below the rapid heating portion 65a to provide heat exchange therebetween. In the rapid heating portion 65a, the temperature is gradually increased from about 700 ° C to 850 ° C, while in the solubilization portion, the temperature is gradually increased from about 850 ° C to 1150 ° C. In the quench section, the temperature is gradually reduced from about 1150 ° C to 650 ° C. Cryogenic support devices in the form of trolleys 80a are provided, which can accommodate at least one tube 85a and feed the tube through the drying / preheating zone 10a. The cold trolley 80a may be made of mild steel, for example two outer side frames joined by a cross beam with eight stainless steel tube rollers 90a (4 pairs, one pair for each tube 85a to be heat treated). Made of. Each of the rollers 90a is mounted on a side frame and is driven by, for example, an electric motor (not shown). Note that the dimensions and spacing of rollers 90a are adapted to the dimensions of the tube to be heat treated. Therefore, different trolleys may be provided for different tube sizes. This allows the furnace 5a to accommodate heating of different sized tubes 85a. Also provided are high temperature support devices in the form of trolleys 95a, which are capable of accommodating at least one tube 85a and feed the tubes through the combustion zone 25a. In this example, the hot trolley 95a is similar in design to the cold trolley 80a except that the rollers 100a are made from silicon carbide, because the trolley 95a reduces heat loss from the combustion zone 25a. In addition, insulating end plates 110a may be provided at both ends thereof. The provision of the silicon carbide roller 100a allows the furnace 5a to be operated at a higher temperature than a normal furnace, for example up to a temperature of about 1400 ° C. Also note that the dimensions and spacing of the rollers 100a are adapted to the particular tube dimensions to be heat treated, thus allowing the furnace 5a to accommodate heating of different sized tubes 85a. Between the discharge part of the dry / pre-tropical zone 10a and the input part of the combustion zone 25a, and hence between the discharge part of the combustion zone 25a and the input part of the cooling zone 40a, there are first and second atmospheric pressures / hydraulic pressures. A transition zone 115a having scissor platforms 120a, 125a is provided. The first platform 120a is moveable between a first position at substantially the same height as the outlet of the dry / pretropical zone 10a and a second position at substantially the same height as the inlet of the cooling zone 40a, while The two-platform 125a is movable between a first position having substantially the same height as the input portion to the combustion zone 25a and a second position having substantially the same height as the discharge portion of the combustion zone 25a. Furthermore, the first and second positions of the two platforms 120a, 125a are approximately equal in height. Also, a plurality of laterally aligned lifting arms (not shown) are provided in the transition zone 115a and have at least as many lifting arms as the tubes 85a in the trolleys 80a, 95a. Another transition zone 130a is provided between the upper level discharge section 135a of the combustion zone 25a and the lower level injection section 140a of the combustion zone 25a. The transition zone 130a is between a first position at substantially the same height as the discharge section at the upper level of the combustion zone 25a and a second position at substantially the same height at the injection section at the lower level of the combustion zone 25a. A movable third atmospheric / hydraulic scissor platform 145a is provided. In use, the tube 85a is extruded onto a cold trolley 80a and conveyed to the input end 15a of the dry / pretropical 10a. The trolley 80a is then pushed through the furnace 5a in a continuous and intermittent fashion by an extendable ram (not shown), i.e. the trolley 85a is pushed into position for any set period. At the same time, the roller 90a is rotated so that it is always rotatable as the tube 85a is dried, and thus is not unevenly dried or distorted. One end of the roller 90a is fixed by a chain sprocket (not shown) and is driven by either an electric motor on each individual trolley 85a coupled to an endless transmission chain or busbar system. The cold trolley 80a is then extruded into the transition section 115a and pushed onto the first platform 120a in the raised first position. The lifting arm is then pushed into the center of the tube 85a and the platform 120a and thus the trolley 85a is lowered leaving the tube 85a on the arm. The arm is then moved across the transition section 115a until the tube 85a is above the empty hot trolley 95a on the second platform 125a in or near the raised first position. The height of the platform 125a is then adjusted until the tube 85a rests on the roller 90a, at which time the arm may be retracted and the trolley 95a pushed into the combustion zone 25a. It should be noted that the ambient temperature is maintained at a low level as the trolley 95a exits the dry / pretropical zone 10a and is fed into the transition zone 115a. It is important that the temperature of tube 85a be maintained, so the transition time should be as fast as possible. Therefore, the entire transition zone 115a needs to be insulated. The trolley 95a is then pushed through the upper portion of the combustion zone 25a and then onto the third platform 145a in the raised position. The third platform 145a is then lowered to its second position, and the trolley 95a is pushed by another pusher (not shown) into the lower portion of the combustion zone 25a and fed therethrough. To be In a similar manner as in the drying / preheating section 10a, the roller 90a may be rotated as needed to provide even heating and prevent distortion of the tube 85a. After passing the lower level of the combustion zone 25a, the trolley 95a is pushed into the transition zone 115a and onto the second platform 125a in the second position below it. The lifting arm then transitions onto the cold trolley 80a waiting on the first platform 120a at its second lower level after lifting the tube 85a upwards. The trolley 80a is then pushed into and passes through the cooling section 40a. Description of the Second Embodiment Referring to FIGS . 8 to 15, a drying / pretropical zone 10b having input and discharge ends 15b, 20b and a combustion zone 25b having input and discharge positions 30b, 35b. And a cooling zone 40b having input and discharge ends 45b, 50b, and a second embodiment of a furnace according to the invention, indicated generally by 5b, is provided. The division of the dry / pre-tropical zone 10b and the cooling zone 40b and the temperature gradient in them may be substantially the same as in the first embodiment. Similarly, the cooling zones 40b are installed under the drying / pretropical zone 10b to provide heat exchange therebetween, as in the first embodiment. Further, the combustion zone 25b may be suitably divided into portions having substantially the same temperature gradient as that of the first embodiment. However, in the second embodiment, the combustion zone 25b comprises a continuous rectangular closed loop, as best seen in FIG. Cryogenic support devices in the form of trolleys 80b are provided, which can accommodate at least one tube 85b and feed the tube 85b through the drying / preheating zone 10b. The cold trolley 80b may be made from mild steel, for example two outer sides joined by crossbeams with rollers 90b of eight stainless steel tubes (three pairs, one pair for each tube 85b to be heat treated). Made of frame. Each of the rollers 90b is mounted on a side frame and driven by, for example, an electric motor (not shown). Note that the dimensions and spacing of rollers 90b are adapted to the dimensions of the tube to be heat treated. Therefore, different trolleys may be provided for different tube sizes. This allows the furnace 5b to be adapted for heating differently sized tubes 85b. Also provided are high temperature support devices in the form of walking frames (beams) 95b, which are capable of accommodating at least one tube 85b and feeding the tubes through the combustion zone 25b. The walking frame 95b is similar in material structure to the high temperature trolley 95a of the first embodiment. However, the walking frame 95b has no wheels. The walking frame 95b may be pushed back and forth along parallel rails 96b, 97b by multiple hydraulic rams or the like (not shown). The rotatable roller 100b of the hot walking frame 95b is made from silicon carbide and the frame 95b also has end plates (not shown) insulated at its ends to reduce heat loss from the combustion zone 25b. You may have. Note again that the dimensions and spacing of rollers 100b are adapted to the dimensions of the particular tube to be heat treated. Between the discharge position of the dry / pre-tropical zone 10b and the charging position 30b of the combustion zone 25b, and between the discharge position 35b of the combustion zone 25b and the charging position 45b of the cooling zone 40b, there are first and second empty spaces. A transition zone 115b having a pressure / hydraulic scissor platform 120b, 125b is provided. The first platform 120b is movable between a first position, which is approximately the same height as the outlet of the dry / pretropical zone 10b, and a second position, which is approximately the same height at the input of the cooling zone 40b. is there. Similarly, the second platform 125b is between a first position that is approximately the same height as the discharge of the dry / pretropical zone 10b and a second position that is approximately the same height as the input of the cooling zone 40b. Is movable. Further, the first and second positions of the two platforms 120b, 125b are approximately equal in height. Also, a plurality of laterally aligned lifting arms (not shown) are provided within the transition zone 115b, and there are at least as many lifting arms as there are tubes 85b in the trolley 80b and walking beam 95b. In use, the tube 85b is extruded onto a cold trolley 80b and conveyed to the input end 15b of the drying / pre-temperature 10b. The trolley 80b is then pushed through the furnace 5b in a continuous and intermittent fashion by an extendable ram (not shown), i.e. the trolley 85b is pushed up one position at every set period. At the same time, the roller 90b is rotated so that the tube 85b is always rotatable as the tube 85b is dried, and thus is not unevenly dried or distorted. One end of the roller 90b is fixed by a chain sprocket (not shown) and is driven by either an electric motor on each individual trolley 85b coupled to an endless transmission chain or bus bar system. The cold trolley 80b is then extruded into the transition 115b and onto the first platform 120b at its first. The lifting arm is then pushed into the center of tube 85b and platform 120b, and thus trolley 85b, is lowered leaving tube 85b on the arm. The arm is then moved across the transition 115b until the tube 85b is over the empty hot walking frame 95b located on the combustion zone 25b. The arm height is then adjusted until the tube 85b rests on the roller 90b, at which time the arm may be retracted and the walking frame 95b pushed along within the combustion zone 25b. It should be noted that when the trolley 80b is passed through the dry / pretropical zone 10b into the transition zone 115b, the ambient temperature is maintained at a low level. It is important that the temperature of tube 85b be maintained, so the transition time should be as fast as possible. Therefore, the entire transition zone 115b needs to be insulated. Each walking frame 95b is then pushed through the combustion zone 25b by a hydraulic ram (not shown). In a similar manner as in the drying / preheating section 10b, the rollers 90b may be rotated as needed to provide even heating and prevent distortion of the tube 85b. After passing through the combustion zone 25b and eventually to the discharge position 35b, the tube 85b is lifted from the walking beam 95b and moved onto the trolley 80b on the second platform 125b, which in turn lowers the second platform below it. It is lowered to the second position. The trolley 80b is also pushed (eg by a ram) onto the first platform 120b at its second lower level. The trolley 80b is then pushed into and passes through the cooling section 40b. Examples of the present invention in summary above, given only as examples and are not intended as limiting the scope of the present invention in any way. The timing of the pushing of the trolley / walking frame 80a, 95a, 80b, 95b and the transition within the transition zones 115a, 130a, 115b is important, but when the invention is provided, the timing is It should be especially acknowledged to the expert. For this reason, this has not been discussed in detail. Also, the strips 10a, 25a, 40a, 10b, 25b, 40b are insulated from and made of materials well known in the art. Further, heating / cooling of the tubes 85a, 85b within each strip 10a, 25a, 40a, 10b, 25b, 40b may be performed by techniques and equipment conventional for furnaces. However, it is noted that in the solubilized portion 70a, when the trolley 95a is stationary and the tube 85a rotates, the tube 85a may be combusted by the combustion of a burner below the bore of the tube 85a, eg, a high velocity gas burner. Should be. In this way, the trolley 95a may be moved intermittently and stopped when the tube 85a meets the burner. Thus, the tubes 85a are fully supported along their length as they pass through the "plastic stage". This is a new combustion technique. Further, it should be noted that in the quench section 40a, the tube 85a may be cooled from about 1150 ° C to 65 ° C in about 10 minutes by blowing cold air below the bore of the tube 85a. This imparts an annealing step on the tubes 85a by stressing the tubes 85a, which also increases their strength. This is a new cooling technique. Also, within the bands 10a, 25a, 40a, 10b, 25b, 40b and on the various platforms 120a, 125a, 140a, 120b, 125b, the trolley / walking frames 80a, 95a, 80b, 85b are advantageously rails. You may drive over. Finally, baffles, etc., are placed on the various strips 10a, 25a, 40a, 10b, 25b, 40b to assist in insulating and separating the strips 10a, 25a, 40a, 10b, 25b, 40b from each other. It may be provided in the charging part of the and the discharging part from the belt.

Claims (1)

[Claims]   1. In a furnace for heat treating tubes, a drying / preheating zone, a combustion zone, a cooling zone and the zone One or more, each supporting one or more tubes through at least one of the It is equipped with a conveyor device that transfers more than this support device, and each pipe is Supported on each of the supporting devices at approximately right angles to the direction, each supporting device Furnace further comprising a device for rotating each tube supported thereon along the length of the tube .   2. A furnace according to claim 1, wherein the support in at least one zone. A furnace whose holding device includes a trolley with wheels.   3. In the furnace according to claim 1 or 2, at least one zone The furnace in which the support device in the includes a walking beam.   4. In the furnace according to any one of claims 1 to 3, the adjacent Abutment strips from support devices used in one strip to support devices used in the next strip A furnace separated from each other by a transition zone with a device for transitioning tubes.   5. A furnace according to any one of claims 1 to 4, wherein: The supporting device used in the drying / preheating zone and the cooling zone is made of mild steel. A furnace in which the device for rotating each tube is made from stainless steel.   6. A furnace according to any one of claims 1 to 5, wherein: The supporting device used in the combustion zone is made of mild steel and rotates the tubes. The furnace is made of silicon carbide.   7. A furnace according to any one of claims 1 to 6, wherein: The supporting device used in the combustion zone has two ends to reduce heat loss. A furnace with an insulating plate.   8. A furnace according to any one of claims 1 to 7, wherein: Note that the combustion zone forwards in the opposite direction so as to provide heat exchange between the lower and upper parts. A furnace having a lower portion through which the support device passes and an upper portion.   9. A furnace according to any one of claims 1 to 8, wherein: The combustion zone has an upper rapid heating section and a lower solubilization section and rapid cooling section. Furnace.   10. In the furnace according to any one of claims 1 to 9, So that the dry / pretropical zone provides heat exchange between the cooling zone and the dry / pretropical zone A furnace provided above the cooling zone.   11. A furnace according to any one of claims 1 to 10 A furnace in which the drying / preheating zone includes a drying portion and a preheating / mineralizing portion.   12. Use in a furnace as claimed in any one of claims 1 to 11. A support device for use in which at least one support device extends through at least one of the bands. Or more tubes can be supported and transported and each tube can be rotated along its length. A supporting device further comprising a device for performing.   13. In a method of heat treating a tube, along the longitudinal direction of each said tube Place the tubes on a supporting device that has a device to rotate each tube supported by Conveyor device through at least one zone of the furnace including a zone, a combustion zone and a cooling zone Therefore, each supporting device is transferred, and each pipe is moved substantially perpendicularly to the direction of transfer. A method including being supported on.   14. Dry / pretropical zone, combustion zone, cooling zone and one or more through each zone In a furnace for heat treating the material, including a conveyor device for transferring the material above. By a transition zone having a device that transforms the material from one zone to the next Furnaces separated from each other.   15. The furnace of claim 14, wherein one or more of the materials are The material is supported on a supporting device, which can be transported by the conveyor device. A furnace that is capable.   16. The furnace according to claim 14 or 15, wherein the combustion zone is , The supporting device in the opposite direction so as to provide heat exchange between the lower part and the upper part. A furnace having a lower portion through which the and the upper portion pass.   17． The furnace according to any one of claims 14 to 16 The combustion zone has an upper rapid heating portion, a lower solubilization portion and a rapid cooling portion. Including a furnace.   18. The furnace according to any one of claims 14 to 17 The dry / pretropical zone provides heat exchange between the cooling zone and the dry / pretropical zone. A furnace provided above the cooling zone.   19. The furnace according to any one of claims 14 to 18 And the dry / pretropical zone includes a dry portion and a preheat / mineralization portion.   20. In a method of heat treating a material, feeding said material through drying / preheating , Transitioning the material to the combustion zone through the first transition zone and sending the material through the combustion zone, Then, transferring the material to a cooling zone via a second transition zone.