Mixed-flow cooling fan for bell-type furnace and using and installing method of mixed-flow cooling fan

Abstract

The mixed-flow cooling fan comprises a centrifugal impeller, an axial-flow impeller, a cover plate and a motor, the motor is fixed to one side of the cover plate, the centrifugal impeller is fixed to the other side of the cover plate and connected with an output shaft of the motor through a shaft disc, the axial-flow impeller is fixed into the centrifugal impeller, and the axial-flow impeller is fixed to the other side of the cover plate and connected with the output shaft of the motor through a shaft disc. According to the centrifugal fan, through structural optimization, the cooling effect of the cooling fan is enhanced, the cooling time is shortened, meanwhile, airflow passes through the axial flow impeller, the internal energy loss of the fan is reduced, the operation efficiency of the fan is improved, and the noise of the fan is reduced.

Description

Technical Field

[0001] The present application relates to the technical field of bell-type furnaces, and in particular to a mixed flow cooling fan for bell-type furnaces and a method for using and installing the fan. Background Art

[0002] The cooling hood of the hood-type furnace adopts convection duct and water mist alternating cooling technology. When the cooling hood is placed on the inner hood at the uniform heating temperature (that is, the charge has just been uniformly heated), the charge is rapidly cooled to about 160°C (the hot spot in the steel coil) under the combined action of air cooling / water cooling. At the beginning of cooling, the cooling fan on the top of the cooling hood draws cold air from the lower part of the high-temperature inner hood, so that the surface temperature of the inner hood is reduced to below about 200°C, thereby avoiding the rapid cooling shock caused by the subsequent water spray, which causes the inner hood to crack. The use of the cooling fan can extend the service life of the inner hood. After a certain period of time (the duration is determined by the actual cooling conditions and the temperature, about 3-5 hours), the cooling fan automatically turns off, the water spray device starts to spray water, and the heat inside the steel coil is transferred to the inner hood by convection. The water flow on the inner hood quickly takes away the heat, and the entire cooling process is carried out automatically.

[0003] The cooling hood fans currently used basically all adopt the traditional centrifugal fan structure, which has the following disadvantages: 1. The airflow in and out direction of the centrifugal fan is perpendicular to the axis, resulting in large energy loss inside the fan and low efficiency; 2. Although the centrifugal fan has a high pressure head, the air flow per unit time is not large, and the cooling effect is poor, resulting in low steel output from the bell-type furnace, and the inner cover works at high temperature for a long time, shortening its service life; 3. After the airflow enters the fan at a high speed, the flow direction of the medium is changed by the centrifugal fan, resulting in high noise.

[0004] Therefore, it is necessary to propose a mixed flow cooling fan for a bell-type furnace and a method for using and installing the fan to solve the above problems. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a mixed flow cooling fan for a bell-type furnace and a method for using and installing the fan in order to overcome the shortcomings of the centrifugal fan and absorb the advantages of the axial flow fan.

[0006] The embodiment of the present application is implemented as follows: An embodiment of the present application provides a mixed flow cooling fan for a hood-type furnace, characterized in that it includes a centrifugal impeller, an axial flow impeller, a cover plate and a motor, wherein the motor is fixed to one side of the cover plate, the centrifugal impeller is fixed to the other side of the cover plate and is connected to the output shaft of the motor through a shaft disk, the axial flow impeller is fixed inside the centrifugal impeller and is coaxially arranged with the centrifugal impeller, and the cover plate is connected to the cooling hood shell.

[0007] In some alternative embodiments, the centrifugal impeller includes a front disc, blades, and a rear disc, which are formed into a whole by welding. The shaft disc is welded and fixed to one side of the rear disc, and the end of the shaft disc is connected to the fixing plate by fastening screws.

[0008] In some alternative embodiments, the axial-flow impeller includes a sleeve and axial-flow blades. The sleeve is welded and fixed to the center of the rear disc and is coaxially arranged with the centrifugal impeller. The axial-flow blades are evenly spaced and arranged circumferentially along the sleeve.

[0009] In some alternative embodiments, a hemispherical head is welded to the end of the sleeve.

[0010] In some alternative embodiments, the shaft disc and the output shaft of the motor are tightly connected by interference fit through a keyway.

[0011] In some alternative embodiments, the end of the hemispherical head and the end face of the front disc are in the same plane.

[0012] A method for using a mixed-flow cooling fan for a bell-type furnace, characterized by including the following content: When a hot steel billet is placed in the cooling hood, after the steel billet is air-cooled or water-cooled by itself, a large amount of water vapor and heat are generated. Start the motor, drive the centrifugal impeller and the axial-flow impeller to operate through the motor, utilize the axial suction of the axial-flow impeller to increase the air intake of the fan, and make the air flow smoothly enter the inlet of the centrifugal impeller. Then, utilize the centrifugal force generated by the rotation of the centrifugal impeller to discharge a large amount of high-temperature gas in the furnace, so that the temperature of the cooling hood is rapidly reduced to below 200 °C.

[0013] A method for installing a mixed-flow cooling fan for a bell-type furnace, characterized by including the following content: The centrifugal impeller is connected to the motor by interference fit through a shaft disc and a keyway. The axial-flow impeller is welded to the centrifugal impeller to form a whole. After the welding is completed and qualified by non-destructive testing, dynamic balance correction is carried out, and the cover plate is directly connected and locked to the cooling hood housing by bolts and nuts to complete the installation.

[0014] In some alternative embodiments, the cover plate and the cooling hood housing are connected by sixteen sets of bolts and nuts.

[0015] In some alternative embodiments, the motor and the cover plate are connected by four sets of bolts and nuts.

[0016] The beneficial effects of the present application are as follows: 1. For the mixed-flow cooling fan for bell-type furnace and its using and installation methods provided by the present application, the design method of centrifugal impeller plus axial-flow impeller is adopted. The air flow enters the axial-flow impeller horizontally, enabling the air flow to uniformly enter the inlet of the centrifugal impeller, thereby reducing the internal energy loss of the impeller and improving the efficiency of the cooling fan; 2. By adding an axial-flow impeller, while maintaining the characteristics of high head of the centrifugal fan, the axial suction force of the axial-flow impeller is utilized to increase the air intake of the cooling fan, enhance the cooling effect, shorten the cooling time, increase the steel output of the bell-type furnace, reduce the working time of the inner hood at high temperature, and extend the service life; 3. After the air flow passes through the axial-flow impeller, the air flow gradually and smoothly enters the centrifugal impeller, reducing the air flow fluctuation and lowering the noise of the cooling fan. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present application, and thus should not be regarded as limiting the scope. For those of ordinary skill in the art, other related drawings can be obtained based on these drawings without creative efforts.

[0018] Figure 1 It is a side view of the mixed-flow cooling fan according to an embodiment of the present application; Figure 2 It is a rear view of the mixed-flow cooling fan according to an embodiment of the present application; Figure 3 It is a front view of the mixed-flow cooling fan according to an embodiment of the present application; Figure 4 It is an inner view of the centrifugal impeller according to an embodiment of the present application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0019] To make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some, but not all, of the embodiments of the present application. Usually, the components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various different configurations.

[0020] Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the present application to be protected, but merely represents the selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present application.

[0021] It should be noted that like reference numerals and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures.

[0022] In the description of the present application, it should also be noted that unless otherwise clearly specified and limited, the terms "arranged", "installed", "connected", and "coupled" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific situations. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0023] The features and performance of the present application will be further described in detail below in conjunction with embodiments.

[0024] As Figures 1-4 shown, in this embodiment, a mixed-flow cooling fan for a bell-type furnace is proposed, which includes a centrifugal impeller, an axial-flow impeller, a cover plate 1, and a motor 2. The motor is fixed on one side of the cover plate, the centrifugal impeller is fixed on the other side of the cover plate, and is connected to the output shaft of the motor through a shaft disc 3. The axial-flow impeller is fixed inside the centrifugal impeller and is coaxially arranged with the centrifugal impeller. The cover plate is connected to the cooling hood housing 4.

[0025] On the basis of the original centrifugal cooling hood fan, the present invention further optimizes the design, overcomes the deficiencies of the centrifugal fan, absorbs the advantages of the axial-flow fan, and develops a new type of mixed-flow fan. An axial-flow impeller is added at the front end of the original centrifugal fan.

[0026] The centrifugal impeller includes a front disc 5, blades 6, and a rear disc 7, which are formed into a whole by welding. The shaft disc is welded and fixed on one side of the rear disc. The end of the shaft disc is connected to a fixing plate 8 through a fastening screw. The shaft disc and the output shaft of the motor are connected and fastened by interference fit through a keyway 9.

[0027] The axial-flow impeller includes a sleeve 10 and axial-flow blades 11. The sleeve is welded and fixed at the center of the rear disc and is coaxially arranged with the centrifugal impeller. The axial-flow blades are evenly spaced along the circumferential direction of the sleeve.

[0028] A hemispherical head 12 is welded to the end of the sleeve to form a complete and closed axial-flow impeller. The end of the hemispherical head is in the same plane as the end face of the front disc.

[0029] Embodiment 1 When the above-mentioned mixed-flow cooling fan is adopted, the following contents are included: When a hot steel billet is placed in the cooling cover, after the steel billet is cooled by its own air cooling or water cooling, a large amount of water vapor and heat are generated. The motor is started, and the centrifugal impeller and the axial-flow impeller are driven by the motor to operate. By using the axial suction of the axial-flow impeller, the air intake of the fan is increased, and the air flow enters the inlet of the centrifugal impeller smoothly. Then, by using the centrifugal force generated by the rotation of the centrifugal impeller, a large amount of high-temperature gas in the furnace is discharged, so that the temperature of the cooling cover is rapidly reduced to below 200 °C, thereby greatly increasing the service life of the inner cover. After the cooling fan has run for a period of time, when the inner cover of the bell-type furnace reaches the specified temperature, the cooling fan will automatically turn off. Through the successful development of the mixed-flow fan, under the same conditions, the air volume of the fan is greatly increased, the cooling time of the steel billet can be greatly shortened, thereby increasing the steel output of the bell-type furnace, reducing the working time of the inner cover in the high-temperature environment, reducing the damage rate of the inner cover, and delaying the service life of the inner cover.

[0030] Embodiment 2 The installation method of the above-mentioned mixed-flow cooling fan: The centrifugal impeller is connected to the motor by interference fit through the shaft disc and the keyway. The axial-flow impeller is welded to the centrifugal impeller to form a whole. After the welding is completed and qualified by non-destructive testing, dynamic balance correction is carried out. The cover plate is directly connected and locked to the cooling cover shell by bolts and nuts to complete the installation.

[0031] In some alternative embodiments, the cover plate is connected to the cooling cover shell by sixteen sets of bolts and nuts; the motor is connected to the cover plate by four sets of bolts and nuts.

[0032] For each elementary section of the new mixed-flow impeller blade profile of the present invention, it is nearly radial or radially formed. Therefore, at high circumferential speeds, after the air flow enters the axial-flow impeller, driven by the rotation of the axial-flow impeller, more gas can enter the centrifugal impeller, thereby enhancing the cooling effect and shortening the cooling time. At the same time, by optimizing the axial-flow impeller, the air flow can enter the centrifugal impeller radially or tend to be radial, thereby reducing the internal energy loss of the fan, improving the operating efficiency of the fan, and reducing the fan noise.

Claims

1. A mixed-flow cooling fan for a bell-type furnace, characterized in that, It includes a centrifugal impeller, an axial-flow impeller, a cover plate and a motor. The motor is fixed to one side of the cover plate. The centrifugal impeller is fixed to the other side of the cover plate and is connected to the output shaft of the motor through a shaft disc. The axial-flow impeller is fixed inside the centrifugal impeller and is coaxially arranged with the centrifugal impeller. The cover plate is connected to the cooling hood housing.

2. The mixed-flow cooling fan for a bell-type furnace according to claim 1, wherein, The centrifugal impeller includes a front disc, blades and a rear disc, which are formed into a whole by welding. The shaft disc is welded and fixed to one side of the rear disc, and the end of the shaft disc is connected to a fixing plate through a fastening screw.

3. The mixed-flow cooling fan for a bell-type furnace according to claim 2, characterized in that, The axial-flow impeller includes a sleeve and axial-flow blades. The sleeve is welded and fixed to the center of the rear disc and is coaxially arranged with the centrifugal impeller. The axial-flow blades are uniformly arranged at intervals along the circumferential direction of the sleeve.

4. The mixed-flow cooling fan for a bell-type furnace according to claim 3, wherein, A hemispherical head is welded to the end of the sleeve.

5. The mixed-flow cooling fan for a bell-type furnace according to claim 1 or 4, characterized in that The shaft disc and the output shaft of the motor are tightly connected by interference fit through a keyway.

6. The mixed-flow cooling fan for a bell-type furnace according to claim 4, wherein, The end of the hemispherical head and the end face of the front disc are in the same plane.

7. The usage method of a mixed-flow cooling fan for a bell-type furnace according to claim 4 or 6 above, characterized in that, It includes the following content: When a hot steel billet is placed in the cooling hood, after the steel billet is air-cooled or water-cooled by itself, a large amount of water vapor and heat are generated. The motor is started, and the centrifugal impeller and the axial-flow impeller are driven by the motor to operate. By using the axial suction of the axial-flow impeller, the air intake of the fan is increased, and the air flow is smoothly introduced into the inlet of the centrifugal impeller. Then, by using the centrifugal force generated by the rotation of the centrifugal impeller, a large amount of high-temperature gas in the furnace is discharged, so that the temperature of the cooling hood is quickly reduced to below 200°C.

8. The installation method of a mixed-flow cooling fan for a bell-type furnace according to claim 4 or 6 above, characterized in that, It includes the following content: The centrifugal impeller is connected to the motor by interference fit through a shaft disc and a keyway. The axial-flow impeller is welded to the centrifugal impeller to form a whole. After the welding is completed and qualified by non-destructive testing, dynamic balance correction is carried out. The cover plate is directly connected and locked to the cooling hood housing by bolts and nuts to complete the installation.

9. The installation method of a mixed-flow cooling fan for a bell-type furnace according to claim 8, characterized in that, The cover plate and the cooling hood housing are connected by sixteen sets of bolts and nuts.

10. The installation method of a mixed-flow cooling fan for a bell-type furnace according to claim 8, characterized in that, The motor and the cover plate are connected by four sets of bolts and nuts.

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