Mixing and stirring device for smelting manganese-rich slag by utilizing silicon carbide waste slag
By designing a mixing and stirring device with rotatable stirring main cylinder and dual drive system, the problem of unstable manganese slag quality caused by layering effect in traditional smelting processes is solved, and efficient manganese ore material selection and smelting effect is achieved, which enhances the Safety and stability.
Patent Information
- Application Number
- CN202411525986.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-30
- Publication Date
- 2024-12-06
- Estimated Expiration
- Not applicable · inactive patent
AI Technical Summary
In the traditional process of smelting manganese-rich slag in silicon carbide waste slag, the layering effect is caused by the different quality of silicon carbide waste slag and manganese ore, resulting in inconcentration of materials, which in turn makes the quality of manganese-rich slag unstable.
A mixing and stirring device is designed, including a rotatable conical cylindrical stirring main cylinder, a stirring impeller section and a dual drive system. The layering and material selection of manganese ore is achieved through the rotation and centrifugal separation effect, combining spiral conductor tubes and electromagnetics. Iron and other designs avoid flying materials and caking materials, and achieve effective contact and crushing of silicon carbide waste slag and manganese ore.
It improves the quality stability of manganese-rich slag, reduces energy consumption, realizes efficient stirring and grading, enhances safety, and is suitable for the material selection and smelting effect of manganese ore during smelting.
Smart Images
Figure CN119075747A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of smelting auxiliary stirring equipment, and in particular to a mixing stirring device for smelting manganese-rich slag using silicon carbide waste slag. Background Art
[0002] At present, manganese-rich slag is smelted from silicon carbide waste slag. Silicon carbide waste slag, coke and manganese ore are added to the blast furnace in a predetermined proportion, and a selective reduction reaction is carried out at a high temperature of ≥1600℃. The traditional process is to achieve effective mixing through mixing and stirring. However, this method will lead to stratification effect due to the different qualities of silicon carbide waste slag and manganese ore, making the materials unconcentrated, and thus making the quality of manganese-rich slag unstable after smelting. Therefore, in order to solve this problem, we propose a mixing and stirring device for smelting manganese-rich slag using silicon carbide waste slag. Summary of the invention
[0003] In view of the defects in the prior art, the present invention provides a mixing and stirring device for smelting manganese-rich slag using silicon carbide waste slag to improve product stability.
[0004] In the first aspect, the present invention provides a mixing and stirring device for smelting manganese-rich slag using silicon carbide waste slag, comprising: a main frame; a stirring main barrel, the stirring main barrel is rotatably mounted on the main frame, the stirring main barrel is in the shape of a cone; the stirring main barrel is provided with a main barrel section and a central shaft section; the central shaft section is arranged at the center of the main barrel section and passes through the main barrel section; the central shaft section is hollow; a stirring impeller section; the stirring impeller section is rotatably mounted in the stirring main barrel; the stirring impeller section comprises a stirring main blade and a stirring main shaft; the stirring main The shaft is rotatably installed at the central shaft section and passes through the central shaft section; one end of the stirring main shaft is fixedly connected to the stirring main blade; the other end of the stirring main shaft extends outward along the axial direction of the central shaft section; and a driving part, the driving part includes a driving main part and a driving auxiliary part, the driving main part is installed on the main frame, and the driving part is transmission-connected to the stirring main cylinder and drives the stirring main cylinder to rotate; the driving auxiliary part is arranged below the main frame, and is transmission-connected to the stirring impeller part and drives the stirring main shaft to rotate.
[0005] Furthermore, the main barrel section is also provided with an anti-flying material ring plate, which is arranged on the inner wall of the main barrel section and close to the top of the stirring main blade. In actual use, the purpose of this design is to avoid flying materials; in actual work, the material, that is, the crushed manganese ore, is first directly placed into the main barrel section. Under the action of the anti-flying material ring plate, the manganese ore in the rotating main barrel section can be prevented from flying out; in this way, safety can be greatly improved, and damage to equipment and personnel caused by flying manganese ore can be avoided.
[0006] Furthermore, the mixing main barrel is also provided with a discharge pipe opening, which is provided on the main barrel section, located in the tangent direction of the main barrel section, and communicated with the main barrel section. In actual use, the purpose of this design is to facilitate the overall discharge of materials after mixing.
[0007] Furthermore, it also includes an outer gear ring, which is fixedly mounted on the outer wall of the main barrel section; the main driving component includes a main motor and a driving main gear; the main motor is fixedly mounted on the main frame, and the driving main gear is fixedly mounted on the rotating shaft of the main motor and meshes with the outer gear ring for transmission. In actual use, the purpose of this design is to achieve effective driving of the stirring main barrel and its efficient rotation, so that on the one hand, a separation effect occurs through rotation, that is, active stratification is achieved; in this way, the material selection of manganese ore can be achieved by controlling the rotation speed, of course, after the manganese ore is crushed, so that the quality of the subsequent smelting of manganese-rich slag can be effectively controlled; thereby maintaining product quality stability and quality grading; and facilitating subsequent market sales.
[0008] Furthermore, the stirring main shaft is hollow; wherein the stirring impeller part further comprises a spiral material guide tube, and the spiral material guide tube is installed in the stirring main shaft. In actual use, the purpose of this design is to achieve material lifting, and to lift and transport the silicon carbide waste slag out of its waste slag frame, wherein the lifting is achieved through the spiral material guide tube.
[0009] Furthermore, the stirring main shaft is also provided with at least one discharge port and fastening section, and the stirring main blade is detachably installed at the fastening section, wherein the discharge port is arranged on the stirring main shaft and is close to the stirring main blade. In actual use, the purpose of this design is, on the one hand, to realize the fixed connection between the stirring main blade and the stirring main shaft through the fastening section; in actual design, the fastening section can adopt the design concept of key connection or threaded connection, which is a common fastening method and will not be described here one by one. On the other hand, the discharge port design in this design is to facilitate the discharge of silicon carbide waste slag. Of course, in actual work, the silicon carbide waste slag is first screened and crushed; its purpose is to further facilitate the discharge of silicon carbide waste slag and facilitate its entry into the main barrel section.
[0010] Furthermore, the stirring main blade is provided with at least one, and the cross section of the stirring main blade is a curved surface; and they are evenly installed at the discharge port. On the other hand, the purpose of this design has two aspects. On the one hand, it is to achieve stirring; on the other hand, it is to achieve guidance, that is, to guide the above-mentioned silicon carbide waste slag. First, its cross section is a curved surface, and it is arranged at the discharge port. In this way, when the silicon carbide waste slag comes out of the spiral guide tube through the discharge port, a centrifugal force can be formed on the rotating stirring main shaft of the silicon carbide waste slag, which is convenient for it to impact the inner wall direction of the main barrel section along the axial direction of the curved surface after discharge, and at the same time, it is impacted and delivered with the manganese ore in the main barrel section. On the one hand, it can accelerate the refinement degree of manganese ore after impact crushing, which is more convenient for subsequent smelting. On the other hand; during the impact process, the silicon carbide waste slag will also remain on the surface of the manganese ore. In this way, the contact range with the silicon carbide waste slag during the manganese ore smelting process can be larger and more convenient for smelting manganese-rich slag.
[0011] Furthermore, the stirring impeller part also includes a spring, an electromagnet and a fixed ring block; the fixed ring block is installed on the spiral guide tube; the electromagnet is fixedly installed on the stirring main shaft; the spring is arranged on the spiral guide tube and extends in the direction of the stirring main shaft; one end of the spring is connected to the fixed ring block; the other end of the spring is connected to the electromagnet. In actual use, the purpose of this design is to facilitate the shaking of materials, and its function is to avoid material jamming. In actual work, the spiral guide tube is slidable in the stirring main shaft through the electromagnet and the spring, and the keyway sliding limit is adopted; in this way, when the material jam occurs, including the silicon carbide waste slag being stuck on the spiral guide tube or the silicon carbide waste slag being stuck in the stirring main shaft, then it can avoid the material jamming phenomenon in real time and always maintain the stability of lifting materials.
[0012] Furthermore, the electromagnet is magnetically connected to the fixed ring block. In actual work, the purpose of this design is to achieve magnetic attraction between the electromagnet and the fixed ring block after power is turned on, thereby achieving compression of the spring, and then the spiral material guide tube can slide in the stirring main shaft, which can effectively avoid the occurrence of material jamming and other phenomena.
[0013] Furthermore, the driving auxiliary parts include an auxiliary motor, a transmission gear and a driving gear; the auxiliary motor is fixedly installed in the main frame; the driving gear is installed on the auxiliary motor; the transmission gear is installed on the stirring main shaft, and the transmission gear and the driving gear are connected in a transmission manner. In actual use, the purpose of this design is to realize the rotation of the stirring main shaft; in actual work, by quickly driving the rotation of the stirring main shaft, the material can be quickly lifted, thereby accelerating its centrifugal discharging effect; in this way, compared with the traditional stirring method, this centrifugal discharging impact method makes the dispersion more thorough.
[0014] It can be seen from the above technical scheme that the beneficial effects of the mixing and stirring device for smelting manganese-rich slag using silicon carbide waste slag provided by the present invention are: (1) In actual work, before mixing the manganese ore, it should be crushed and screened first, so as to effectively ensure the stability of product quality; (2) The design of the rotatable stirring main drum adopted in the design makes it possible to separate and stratify the manganese ore during the rotation of the stirring main drum, which makes it easier to select materials and achieves a better stirring effect. After two selections, the quality stability of the finished product is better. (3) The stirring impeller is arranged in a rotatable stirring main cylinder, so that less driving force is required to stir the materials, thereby reducing energy consumption; (4) Furthermore, the dual-drive design effectively realizes the separate rotation of the stirring main cylinder and the stirring impeller, thereby maintaining high stirring efficiency. BRIEF DESCRIPTION OF THE DRAWINGS
[0015] In order to more clearly illustrate the specific embodiments of the present invention, the following briefly introduces the drawings required for the specific embodiments or the prior art description. In all the drawings, each element or part is not necessarily drawn according to the actual scale.
[0016] Figure 1 A schematic front view of a mixing and stirring device for smelting manganese-rich slag using silicon carbide waste slag provided in an embodiment of the present invention; Figure 2 A schematic diagram of the main structure of a mixing and stirring device for smelting manganese-rich slag using silicon carbide waste slag provided in an embodiment of the present invention; Figure 3 A schematic top view of a stirring main blade in a mixing and stirring device for smelting manganese-rich slag using silicon carbide waste slag provided in an embodiment of the present invention; Figure 4 for Figure 3 Schematic diagram of the cross-sectional structure of AA; Reference numerals: Main frame 1, stirring main cylinder 2, main cylinder section 211, anti-flying material ring plate 2111, discharge pipe outlet 2112, central shaft section 212, stirring impeller part 3, stirring main blade 31, stirring main shaft 32, discharge port 321, fastening section 322, spiral material guide pipe 33, spring 34, electromagnet 35, fixed ring block 36, driving part 4, driving main part 41, main motor 411, driving main gear 412, driving auxiliary part 42, auxiliary motor 421, transmission gear 422, driving gear 423, outer ring gear 5. DETAILED DESCRIPTION
[0017] The following embodiments of the technical solution of the present invention are described in detail in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and are therefore only used as examples, and cannot be used to limit the protection scope of the present invention.
[0018] The embodiment is basically as shown in the attached Figures 1 to 4 As shown: like Figure 1 - Figure 4 As shown, the mixing and stirring device provided in this embodiment for smelting manganese-rich slag using silicon carbide waste slag can improve product stability.
[0019] The present invention provides a mixing and stirring device for smelting manganese-rich slag using silicon carbide waste slag, comprising: a main frame 1; a stirring main barrel 2, wherein the stirring main barrel 2 is rotatably mounted on the main frame 1, and the stirring main barrel 2 is in the shape of a cone; the stirring main barrel 2 is provided with a main barrel section 211 and a central shaft section 212; wherein the central shaft section 212 is arranged at the center of the main barrel section 211 and passes through the main barrel section 211; wherein the central shaft section 212 is hollow; a stirring impeller section 3; wherein the stirring impeller section 3 is rotatably mounted in the stirring main barrel 2; the stirring impeller section 3 comprises a stirring main blade 31 and a stirring main shaft 32; wherein the stirring main shaft 32 is rotatable The main frame 1 is provided with a stirring main shaft 32, which is connected to the stirring main blade 31; the other end of the stirring main shaft 32 extends outward along the axial direction of the central shaft section 212; and a driving part 4, wherein the driving part 4 includes a driving main part 41 and a driving sub-part 42, wherein the driving main part 41 is installed on the main frame 1, and the driving part 4 is connected to the stirring main barrel 2 in transmission and drives the stirring main barrel 2 to rotate; the driving sub-part 42 is arranged below the main frame 1, and is connected to the stirring impeller part 3 in transmission and drives the stirring main shaft 32 to rotate. In actual work, before stirring the manganese ore, it is first crushed and screened, so that the stability of product quality can be effectively guaranteed; and the design of the rotatable stirring main barrel 2 adopted in the design makes it possible to have a similar separation and stratification effect on the manganese ore during the rotation of the stirring main barrel 2, so that it is convenient to select materials and make the stirring effect better; after two material selections, the quality stability of the finished product is better; at the same time, the stirring impeller part 3 is arranged in the rotatable stirring main barrel 2, so that only less driving force is needed to stir the materials, reducing energy consumption; and through the dual-drive design, the stirring main barrel 2 and the stirring impeller part 3 are effectively rotated separately, so that its stirring efficiency can be maintained.
[0020] At the same time, in order to avoid flying materials from injuring people or damaging equipment, in this embodiment, the main barrel section 211 is also provided with a flying material prevention ring plate 2111, which is arranged on the inner wall of the main barrel section 211 and close to the upper part of the stirring main blade 31. In actual use, the purpose of this design is to avoid flying materials; in actual work, the material, that is, the crushed manganese ore, is first directly placed into the main barrel section 211. Under the action of the flying material prevention ring plate 2111, the manganese ore in the rotating main barrel section 211 can be prevented from flying out; in this way, safety can be greatly improved, and damage to equipment and personnel caused by flying manganese ore can be avoided.
[0021] In order to facilitate discharging, in this embodiment, the mixing main barrel 2 is further provided with a discharging nozzle 2112, which is provided on the main barrel section 211, located in the tangent direction of the main barrel section 211, and communicated with the main barrel section 211. In actual use, the purpose of this design is to facilitate the overall discharging of the material after mixing.
[0022] In this embodiment, in order to further facilitate the driving of the stirring main barrel 2 to rotate, an outer gear ring 5 is also included, and the outer gear ring 5 is fixedly mounted on the outer wall of the main barrel section 211; the driving main component 41 includes a main motor 411 and a driving main gear 412; the main motor 411 is fixedly mounted on the main frame 1, and the driving main gear 412 is fixedly mounted on the rotating shaft of the main motor 411, and meshes with the outer gear ring 5 for transmission. In actual use, the purpose of this design is to achieve effective driving of the stirring main barrel 2 and achieve its efficient rotation. On the one hand, through rotation, a separation effect occurs, that is, active stratification is achieved; in this way, the material selection of manganese ore can be achieved by controlling the rotation speed, of course, after the manganese ore is crushed, so that the quality of the subsequent smelting manganese-rich slag can be effectively controlled; thereby maintaining product quality stability and quality grading; and facilitating subsequent market sales.
[0023] In this embodiment, the stirring main shaft 32 is hollow; wherein the stirring impeller part 3 also includes a spiral guide tube 33, and the spiral guide tube 33 is installed in the stirring main shaft 32. In actual use, the purpose of this design is to achieve material lifting, to lift and transport the silicon carbide waste slag from its waste slag frame, wherein the lifting is achieved by the spiral guide tube 33. Among them, in this embodiment, in order to facilitate use, the stirring main shaft 32 is also provided with at least one discharge port 321 and a fastening section 322, and the stirring main blade 31 is detachably installed at the fastening section 322, wherein the discharge port 321 is provided on the stirring main shaft 32 and is close to the stirring main blade 31. In actual use, the purpose of this design is, on the one hand, to achieve a fixed connection between the stirring main blade 31 and the stirring main shaft 32 through the fastening section 322; in actual design, the fastening section 322 can adopt a key connection or a threaded connection design idea, which is a more common fastening method and will not be described one by one here. On the other hand, the design of the discharge port 321 in the design is to facilitate the discharge of the silicon carbide waste slag. Of course, in actual work, the silicon carbide waste slag is first screened and crushed; its purpose is to further facilitate the discharge of the silicon carbide waste slag and facilitate its entry into the main barrel section 211.
[0024] In order to facilitate uniform stirring, in this embodiment, the stirring main blade 31 is provided at least at one place, and the cross section of the stirring main blade 31 is a curved surface; and they are evenly installed one by one at the discharge port 321. On the other hand, the purpose of this design has two aspects, one is to achieve stirring; the other is to achieve guidance, that is, the guidance of the above-mentioned silicon carbide waste slag. First, its cross section is a curved surface and is arranged at the discharge port 321. In this way, when the silicon carbide waste slag comes out of the spiral guide tube 33 through the discharge port 321, centrifugal force can be formed on the rotating stirring main shaft 32, which is convenient for it to impact the inner wall direction of the main barrel section 211 along the axial direction of the curved surface after discharge, and at the same time impact delivery with the manganese ore in the main barrel section 211. On the one hand, it can accelerate the refinement of the manganese ore after impact crushing, which is more convenient for subsequent smelting. On the other hand, during the impact process, the silicon carbide waste slag will also remain on the surface of the manganese ore. In this way, the contact area with the silicon carbide waste slag during the manganese ore smelting process can be larger and more convenient for smelting manganese-rich slag.
[0025] At the same time, in order to effectively solve the problem of material jamming during the lifting process, in this embodiment, the stirring impeller part 3 also includes a spring 34, an electromagnet 35 and a fixed ring block 36; the fixed ring block 36 is installed on the spiral guide tube 33; the electromagnet 35 is fixedly installed on the stirring main shaft 32; the spring 34 is arranged on the spiral guide tube 33 and extends toward the stirring main shaft 32; one end of the spring 34 is connected to the fixed ring block 36; the other end of the spring 34 is connected to the electromagnet 35. In actual use, the purpose of this design is to facilitate the shaking of materials, and its function is to avoid jamming. In actual work, the spiral guide tube 33 is slidable in the stirring main shaft 32 through the electromagnet 35 and the spring 34; in this way, when the phenomenon of material jamming occurs, including the silicon carbide waste slag being stuck on the spiral guide tube 33 or the silicon carbide waste slag being stuck in the stirring main shaft 32, then it can avoid the occurrence of material jamming in real time, and always maintain the stability of lifting materials.
[0026] In order to further solve the problem of material jamming, in this embodiment, the electromagnet 35 is magnetically connected to the fixed ring block 36. In actual work, the purpose of this design is to achieve magnetic attraction between the electromagnet 35 and the fixed ring block 36 after power is turned on, thereby achieving compression of the spring 34, and then enabling the spiral material guide tube 33 to slide in the stirring main shaft 32, which can effectively avoid the occurrence of material jamming and other phenomena.
[0027] In this embodiment, the driving sub-component 42 includes a sub-motor 421, a transmission gear 422 and a driving gear 423; the sub-motor 421 is fixedly installed in the main frame 1; the driving gear 423 is installed on the sub-motor 421; the transmission gear 422 is installed on the stirring main shaft 32, and the transmission gear 422 and the driving gear 423 are connected in a transmission manner. In actual use, the purpose of this design is to realize the rotation of the stirring main shaft 32; in actual work, by quickly driving the rotation of the stirring main shaft 32, the material is quickly lifted, thereby accelerating its centrifugal discharging effect; in this way, compared with the traditional stirring method, the centrifugal discharging impact method makes the dispersion more thorough.
[0028] To sum up, the mixing and stirring device for smelting manganese-rich slag using silicon carbide waste slag is not only reasonably designed but also simple to operate. It realizes multiple material selections through the design of rotary centrifugal separation. In addition, it also adopts a centrifugal impact design so that the silicon carbide waste slag impacts the direction of the manganese ore, thereby achieving effective contact between the silicon carbide waste slag and the manganese ore, greatly improving the subsequent stirring effect. Therefore, the device is suitable for industry promotion.
[0029] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. These modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be included in the scope of the claims and specification of the present invention.
Claims
1. A mixing and stirring device for smelting manganese-rich slag using silicon carbide waste slag, It is characterized in that include: Main frame; A stirring main cylinder, the stirring main cylinder is rotatably mounted on the main frame, and the stirring main cylinder is in a cone shape; The mixing main cylinder is provided with a main cylinder section and a central shaft section; wherein the central shaft section is arranged at the center of the main cylinder section and passes through the main cylinder section; wherein the central shaft section is hollow; a stirring impeller portion; the stirring impeller portion is rotatably mounted in the stirring main cylinder; the stirring impeller portion comprises a stirring main blade and a stirring main shaft; the stirring main shaft is rotatably mounted at the central shaft section and penetrates the central shaft section; one end of the stirring main shaft is fixedly connected to the stirring main blade; the other end of the stirring main shaft extends outwardly along the axis direction of the central shaft section; and The driving part includes a driving main part and a driving sub-part. The driving main part is installed on the main frame, and the driving part is connected to the stirring main cylinder by transmission, and drives the stirring main cylinder to rotate; the driving sub-part is arranged below the main frame, and is connected to the stirring impeller part by transmission, and drives the stirring main shaft to rotate.
2. A mixing and stirring device for smelting manganese-rich slag using silicon carbide waste slag according to claim 1, It is characterized in that The main barrel section is also provided with a flying material prevention ring plate, which is arranged on the inner wall of the main barrel section and close to the top of the stirring main blade.
3. A mixing and stirring device for smelting manganese-rich slag using silicon carbide waste slag according to claim 1, It is characterized in that The mixing main barrel is also provided with a discharge pipe opening, which is arranged on the main barrel section, located in the tangent direction of the main barrel section, and communicated with the main barrel section.
4. A mixing and stirring device for smelting manganese-rich slag using silicon carbide waste slag according to claim 1, It is characterized in that It also includes an outer gear ring, which is fixedly mounted on the outer wall of the main barrel section; the driving main component includes a main motor and a driving main gear; the main motor is fixedly mounted on the main frame, and the driving main gear is fixedly mounted on the rotating shaft of the main motor and meshes with the outer gear ring for transmission.
5. A mixing and stirring device for smelting manganese-rich slag using silicon carbide waste slag according to claim 1, It is characterized in that The stirring main shaft is hollow; wherein the stirring impeller portion further comprises a spiral material guide pipe, and the spiral material guide pipe is installed in the stirring main shaft.
6. A mixing and stirring device for smelting manganese-rich slag using silicon carbide waste slag according to claim 1, It is characterized in that The stirring main shaft is also provided with at least one discharge port and a fastening section, and the stirring main blade is detachably mounted at the fastening section, wherein the discharge port is provided on the stirring main shaft and is close to the stirring main blade.
7. A mixing and stirring device for smelting manganese-rich slag using silicon carbide waste slag according to claim 6, It is characterized in that The stirring main blade is provided at least in one place, and the cross section of the stirring main blade is a curved surface; and the stirring main blades are evenly installed at the discharge port.
8. A mixing and stirring device for smelting manganese-rich slag using silicon carbide waste slag according to claim 5, It is characterized in that The stirring impeller part also includes a spring, an electromagnet and a fixed ring block; the fixed ring block is installed on the spiral material guide tube; the electromagnet is fixedly installed on the stirring main shaft; the spring is arranged on the spiral material guide tube and extends toward the stirring main shaft; one end of the spring is connected to the fixed ring block; the other end of the spring is connected to the electromagnet.
9. A mixing and stirring device for smelting manganese-rich slag using silicon carbide waste slag according to claim 8, It is characterized in that The electromagnet is magnetically connected to the fixing ring block.
10. A mixing and stirring device for smelting manganese-rich slag using silicon carbide waste slag according to claim 1, It is characterized in that The driving auxiliary parts include an auxiliary motor, a transmission gear and a driving gear; the auxiliary motor is fixedly installed in the main frame; the driving gear is installed on the auxiliary motor; the transmission gear is installed on the stirring main shaft, and the transmission gear and the driving gear are in driving connection.