Centrifugal fan

Abstract

The utility model provides a centrifugal fan which comprises a centrifugal impeller, a current collector is arranged at the air inlet end of the centrifugal impeller, a volute is sleeved outside the centrifugal impeller, a bearing box is arranged at the rear end of the volute, a base is arranged below the bearing box, a belt pulley is arranged at the tail of the bearing box, and the bearing box and a motor are driven by the belt pulley. The outer portion of the belt is protected through a protective cover, and the motor and the volute are fixed through a base. According to the utility model, the high-temperature resistance of the fan is effectively improved, the heat dissipation effect is effectively enhanced, the explosion-proof risk is reduced, the smoothness and stability of airflow are enhanced, the overall rigidity of a machine body is improved, and the safety and stability of equipment are improved.

Description

Technical Field

[0001] The utility model relates to a centrifugal fan. Background Art

[0002] The final design of the fan is mainly determined by the working environment. Under the working conditions of large air volume and high total pressure, traditional centrifugal fans are mainly used. Because the working environment is a flammable and explosive place, the fan has high requirements for high temperature resistance and explosion protection, and also has high requirements for the fan's aerodynamic performance.

[0003] In the existing technology, when it is necessary to be on some ships with high explosion-proof and high temperature resistance requirements, it is common that high-temperature gas cannot be delivered, or the explosion-proof performance is good but the high temperature resistance is not good, or the high temperature resistance is good but the explosion-proof performance is unsatisfactory. Utility Model Content

[0004] The utility model provides a centrifugal fan.

[0005] The centrifugal fan of the utility model comprises: a collector, a centrifugal impeller, a volute, a bearing box and a motor, wherein:

[0006] The air inlet end of the centrifugal impeller is provided with the collector, and the outer shell of the centrifugal impeller is provided with a volute;

[0007] The rear end face of the volute is connected to the end face of the bearing box, the lower end face of the volute is connected to the bottom plate, the front end face of the volute is connected to the collector, and the centrifugal impeller is connected to the shaft of the bearing box;

[0008] The shaft of the bearing box and the shaft of the motor are connected through a pulley, the bearing box is driven by the motor through the pulley, and the outside of the pulley is protected by a protective cover; water inlet and outlet holes are provided on the volute, the motor housing of the motor and the bearing box.

[0009] Furthermore, in the above centrifugal fan, the centrifugal impeller includes:

[0010] An upper end cover and a chassis with a blade group, a plurality of blade groups are evenly spaced on the chassis of the centrifugal impeller, wherein three blades of different lengths and spaced apart constitute a blade group, and each blade group 21 of three blade units with different shapes is composed of three blade units with different shapes, and the length and curvature of the blade unit of each shape are different. The thickness of each blade unit first gradually increases and then decreases from the tip to the tail. The tip of each blade unit is flush with the outer diameter of the chassis, and the fillet ratio of the tip to the tail of each blade unit is 2:1, wherein the two sides of each blade unit are respectively connected to the upper end cover and the chassis, and each blade unit is arranged between the upper end cover and the chassis; the tip of the chassis side is close to the outer ring of the chassis, and the tail of the chassis side is close to the inner ring of the chassis, wherein the outer ring of the chassis is the outer diameter of the centrifugal impeller, and the inner ring of the chassis is the inner diameter of the centrifugal impeller.

[0011] Furthermore, in the above-mentioned centrifugal fan, in each blade group 21, from the longest blade unit to the shortest blade unit, the fillet sizes of the blade tails in each blade group are R0.8mm, R0.87mm, and R0.95mm, respectively, and the number of blade units with three different shapes is the same.

[0012] Furthermore, in the above-mentioned centrifugal fan, the gap between two adjacent blade units of each blade group on the centrifugal impeller forms an air duct, and air is discharged from the blade tip of the outer ring of the chassis and enters the blade tail of the inner ring of the chassis; the length ratios of the three blade units with different shapes in each blade group are 6:5:3 respectively, and the projection angles of the inlet front edge of the three blade units with different shapes and the outlet tail edge of the blade units on the vertical plane are 88.7°, 50.2°, and 10.8° respectively.

[0013] 35.6°, wherein the inlet leading edge of the blade unit is a circle formed by the blade tails of all blade units with the same shape; the outlet trailing edge of the blade unit is a circle formed by the blade tips of all blade units with the same shape.

[0014] Furthermore, in the above-mentioned centrifugal fan, the bearing housing has two symmetrical first water inlet and outlet cavities inside, which are spiral cavities with a diameter of 100 mm, a cavity spacing of 10.3 mm, and a cavity diameter of 4 mm, with a total of 9 turns, extending to the water inlet and outlet holes on the bearing housing. The water inlet and outlet holes on the bearing housing are connected to the cooling water pipe, and the coolant in the cooling water pipe cools the first cavity;

[0015] The interior of the volute has a second water inlet and outlet cavity, which has an optimal arc R262.3mm, a cavity spacing of 7.8mm, and a cavity diameter of 4.5mm. The inlet and outlet extend to the water inlet and outlet holes on the stainless steel volute; the water inlet and outlet holes on the volute are connected to the cooling water pipe, and the cooling liquid transported by the cooling water pipe cools the cavity;

[0016] The junction box of the motor is connected to the motor casing as an integral whole. There is no gap between the motor casing and the junction box. A third water inlet and outlet cavity with one inlet and one outlet is provided inside the motor casing. The third water inlet and outlet cavity is a spiral cavity with a diameter of 131 mm, a cavity spacing of 8.3 mm, and a cavity diameter of 4 mm. The inlet and outlet extend to the water inlet and outlet holes on the motor casing. The water inlet and outlet holes on the motor casing are connected to the cooling water pipe, and the cooling liquid is transported through the cooling water pipe to cool the cavity.

[0017] Furthermore, in the above-mentioned centrifugal fan, the arc surface of the volute is wrapped from the inside to the outside with three kinds of thermal insulation materials, namely polyurethane, aluminum silicate, and thermal insulation rock wool. The innermost layer is 2mm thick polyurethane, and the outside of the polyurethane is welded and fixed to the volute with a layer of stainless steel mesh with 0.5mm holes, and the outside of the stainless steel mesh is fixed with a layer of 0.1mm fireproof gauze; a 2mm layer of aluminum silicate is added to the outside of the fireproof gauze, and the outside of the aluminum silicate is welded and fixed to the volute with a layer of stainless steel mesh with 0.5mm holes, and the outside of the aluminum silicate is fixed with a layer of 0.1mm fireproof gauze; the outside of the thermal insulation rock wool is welded and fixed to the volute with a layer of stainless steel mesh with 0.5mm holes, and the outside of the thermal insulation rock wool is fixed with a layer of 0.1mm fireproof gauze, and the outside of the thermal insulation rock wool fireproof gauze is welded with a layer of 0.5mm stainless steel arc shell, and the curvature of the front and rear covers of the volute needs to protrude 5mm from the single side of the volute.

[0018] Furthermore, in the above-mentioned centrifugal fan, the collector is also provided with a first arc surface that cooperates with the second arc surface of the upper end cover of the centrifugal impeller, and a copper sheet is installed on the first arc surface. The first arc surface is an irregular arc composed of an R22.3mm arc and an R24.1mm arc, with the surface at a diameter of 235mm of the collector, that is, the junction of the collector and the copper sheet installed on the collector as the starting point. There is a matching gap between the first arc surface of the collector and the second arc surface of the upper end cover of the centrifugal impeller.

[0019] Furthermore, in the above-mentioned centrifugal fan, the stainless steel collector is rolled into two copper arcs using 1mm copper material on the first arc surface where it cooperates with the second arc surface of the upper end cover of the centrifugal impeller, and the two copper arcs are welded to the stainless steel collector to form a whole.

[0020] Furthermore, in the above-mentioned centrifugal fan, the central axis of the air inlet of the collector, the central axis of the air inlet of the volute and the central axis of the bearing box are on a straight line, called the first central axis, and the central axis of the air outlet of the volute is installed on the bearing box at an angle of 90° to the right based on the first central axis.

[0021] Furthermore, in the above centrifugal fan, the collector includes: a conical surface formed by rolling in the middle, which is welded to the front mounting flange and the rear mounting flange respectively welded to the front and rear of the conical surface; wherein,

[0022] A spiral guide groove is provided at the conical surface of the inlet of the collector, wherein the guide groove takes the first central axis of the air inlet of the collector as the central vector, starts at an angle of 21° along the central vector, and takes the front mounting flange with a diameter of 275mm as the reference. It is processed along the central vector of the collector to the starting position of the R angle of the collector. The starting position of the R angle is the junction of the collector and the copper sheet, and is processed into an arc groove with a circle radius of R7.2mm and a groove pitch of 16.7mm.

[0023] The present invention provides a high-temperature resistant and explosion-proof centrifugal fan, comprising a centrifugal impeller, a flow collector provided at the air inlet end of the centrifugal impeller, a volute provided on the outer casing of the centrifugal impeller, a bearing box provided at the rear end of the volute, a base provided below the bearing box, a pulley provided at the tail end of the bearing box, the bearing box and the motor driven by the pulley, the outside of the belt protected by a protective cover, and the motor and the volute both fixed by the base. The present invention effectively improves the high-temperature resistance of the fan, effectively enhances the heat dissipation effect, reduces the risk of explosion protection, enhances the smoothness and stability of the airflow, improves the overall rigidity of the machine body, and improves the safety and stability of the equipment. The present invention has high aerodynamic efficiency, high wind pressure, good cooling effect, and reliable explosion-proof performance.

[0024] Specifically, the beneficial effects of the present invention are:

[0025] (1) Effectively enhance the explosion-proof effect of the fan and improve the full pressure efficiency of the fan;

[0026] (2) Effectively enhance the high temperature resistance of the fan and significantly reduce the noise generated by the fan's air flow;

[0027] (3) Effectively improve the smoothness and stability of the fan airflow. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The present invention is further described below with reference to the accompanying drawings and embodiments;

[0029] Figure 1 This is a schematic diagram of the side and front structure of an embodiment of the utility model;

[0030] Figure 2 for Figure 1 Schematic diagram of the centrifugal impeller;

[0031] Figure 3 This is a schematic diagram of the side and rear structure of an embodiment of the utility model;

[0032] Figure 4 A schematic diagram of a blade according to an embodiment of the present invention;

[0033] Figure 5 for Figure 2 A schematic diagram of the upper end cover of the centrifugal impeller;

[0034] Figure 6 Schematic diagram of the symmetrical double helix cavity inside the bearing box of the utility model;

[0035] Figure 7 Schematic diagram of the internal cavity of the volute of the present invention;

[0036] Figure 8 It is a schematic diagram of the volute insulation layer of the utility model;

[0037] Figure 9 This is a partial enlarged schematic diagram of the volute insulation layer of the utility model;

[0038] Figure 10 A schematic diagram of a current collector of the present invention;

[0039] Figure 11 It is a schematic diagram of the cooperation between the centrifugal impeller and the collector 2 of the utility model.

[0040] Explanation of numbers: 1. Centrifugal impeller; 2. Collector; 3. Volute; 4. Junction box; 5. Motor; 6. Bearing box; 7. Base; 8. Pulley; 9. Bottom plate; 21. Blade group; 22. Copper sheet; 23. Gap; 24. Upper end cover; 25. Chassis; 26. Blade tip; 27. Blade tail; 28. Inlet leading edge; 29. ​​Outlet trailing edge; 30. Guide groove; 31. First cavity; 32. Second cavity for water inlet and outlet; 33. Conical surface; 34. Front mounting flange; 35. Rear mounting flange; 36. First arc surface; 37. Center vector of collector; 38. Second arc surface; 39. Junction; 42. Volute insulation layer; 43. Water inlet and outlet holes. DETAILED DESCRIPTION

[0041] The present invention will be further described in detail below with reference to the embodiments, but the protection scope of the present invention is not limited thereto.

[0042] Example 1

[0043] like Figure 1 、 2As shown in Figure 3, this example designs a high-temperature resistant and explosion-proof centrifugal fan, which includes: a centrifugal impeller 1, a collector 2 is provided at the air inlet end of the centrifugal impeller 1, a volute 3 is provided on the outer sleeve of the centrifugal impeller 1, a bearing box 6 is provided at the rear end of the volute 3, a base 7 is provided below the bearing box 6, a pulley 8 is provided at the tail of the bearing box 6, the bearing box 6 and the motor 5 are driven by the pulley 8, the outside of the pulley 8 is protected by a protective cover 8, the motor 5 and the volute 3 are both fixed by a bottom plate 9, and water inlet and outlet holes 43 are provided on the volute 3, the motor housing of the motor 5, and the bearing box 6.

[0044] like Figure 3 As shown, in this example, a bearing box base 7 is provided below the bearing box 6, and a motor 5 and a bearing box base 7 are installed on the bottom plate 9. A pulley 8 is connected between the tail of the bearing box 6 and the motor 5. The motor 5 is connected to the bearing box 6 through the pulley and belt on the pulley 8, driving the shaft in the bearing box 6 to rotate. The bearing box 6 is fixedly connected to the bearing box base 7, and the centrifugal impeller 1 is connected to the shaft of the bearing box 6. When the shaft rotates, it will drive the centrifugal impeller 1 to rotate together. A volute 3 is installed on the outside of the centrifugal impeller 1, and the rear end face of the volute 3 is connected to the end face of the bearing box 6, the lower end face of the volute 3 is connected to the bottom plate 9, and the front end face of the volute 3 is connected to the collector 3.

[0045] In this example, the motor 5 is powered on and rotated, and the pulley 8 connected to the shaft of the motor 5 drives the shaft of the bearing box 6 to rotate, and then the shaft in the bearing box 6 drives the centrifugal impeller 1 to do work. Through the interaction between the centrifugal impeller 1 and the gas, the gas gains energy and forms an airflow. The airflow passes through the collector 2 and enters the volute 3 after being rectified by the spiral guide groove 30 of the collector 2. After the airflow enters the volute 3, part of the dynamic pressure energy of the gas at the centrifugal impeller 1 is converted into static pressure energy, forming wind pressure, and the gas is gathered at the air outlet of the volute 3. After the flow field is improved to a certain extent by the volute 3, it finally flows out from the air outlet of the volute 3. While the whole machine is operating, the volute 3, the motor housing of the motor 5, and the water inlet and outlet holes 43 on the bearing box 6 begin to circulate cooling water to cool the components.

[0046] The utility model can be applied to ventilation systems whose working medium is flammable and explosive gas, such as exhaust systems of ships used for transporting oil.

[0047] Example 2

[0048] like Figure 2 、 4 As shown in FIG5 , based on Example 1, the centrifugal impeller includes: an upper end cover 24 and a bottom plate 25 with a blade assembly 21,

[0049] The centrifugal impeller 1 has a plurality of blade groups 21 evenly spaced apart on its chassis 25. Each blade group 21 comprises three different lengths and three different blades arranged at intervals, for a total of nine groups. Each blade group 21 is composed of blades of three different lengths and curvatures. The thickness of each blade gradually increases and then decreases from the tip 26 to the tail 27. The tip 26 of each blade unit is flush with the outer diameter of the chassis 25, and the radius ratio of the tip 26 to the tail 27 of each blade unit is 2:1. The two sides of each blade unit are connected to the upper end cover 24 and the chassis 25, respectively. Each blade unit is disposed between the upper end cover 24 and the chassis 25. The blade tip 26 on the chassis 25 side is close to the outer ring of the chassis 25, and the blade tail 27 on the chassis 25 side is close to the inner ring of the chassis 25. The outer ring of the chassis represents the outer diameter of the centrifugal impeller 1, and the inner ring of the chassis represents the inner diameter of the centrifugal impeller 1.

[0050] In each blade group 21 , from the longest blade unit to the shortest blade unit, the rounded corner sizes of the blade tail 27 in each blade group are R0.8mm, R0.87mm, and R0.95mm respectively, and the number of blade units with three different shapes is the same.

[0051] In this embodiment, the centrifugal impeller 1 is matched with the shaft end mounting surface of the bearing housing 6. The rotation of the motor 5 drives the shaft in the bearing housing 6 through the pulley 8 to drive the centrifugal impeller to rotate. The gap between two adjacent blade units of each blade group 21 on the centrifugal impeller 1 forms an air duct, which discharges air from the blade tip 26 of the outer ring of the chassis and enters the blade tail 27 of the inner ring of the chassis. In the specific implementation process, Figure 4 As shown, the nine blade groups 21 are evenly spaced, but the length ratios of the three different blade shapes within each blade group 21 are 6:5:3, respectively. The vertical projection angles between the inlet leading edge 28 and the outlet trailing edge 29 of the three blade shapes are 88.7°, 50.2°, and 35.6°, respectively. The inlet leading edge 28 of the blade unit is defined as the circle formed by the tails 27 of all blade units with the same shape, while the outlet trailing edge 29 of the blade unit is defined as the circle formed by the tips 26 of all blade units with the same shape.

[0052] During the actual machining process, the centrifugal impeller 1 is made of stainless steel. The base 25 and nine blade groups 21 are finely machined in a machining center to evenly distribute the blade units and improve the accuracy of the blade arc. The upper end cover of the centrifugal impeller 1 is then machined in a machining center. During machining, a certain margin is left for the outer diameter, height, and thickness of the upper end cover 24 and the base 25 with the blade groups. Finally, the upper end cover 24 and the base 25 with the blade groups are combined into a single piece, with the blade units arranged between the upper end cover 24 and the base 25. After welding is completed, the entire piece is finely machined. This process improves the accuracy of the centrifugal impeller 1 and the accuracy level of its dynamic and static balance.

[0053] Example 3

[0054] On the basis of Example 2, the centrifugal impeller 1 is matched with the bearing box 6, and the centrifugal impeller 1 is installed on the shaft shoulder of the bearing box 6.

[0055] During the implementation, the shaft in the bearing box 6 is driven by the rotation of the motor 5 through the pulley set 8. Figure 6 As shown, there are two symmetrical groups of first water inlet and outlet cavities 31 inside the bearing box 6. The first water inlet and outlet cavities are spiral cavities with a diameter of 100 mm, a cavity spacing of 10.3 mm, and a cavity diameter of 4 mm, with a total of 9 turns. The water inlet and outlet of the first water inlet and outlet cavities extend to the water inlet and outlet holes 43 on the bearing box 6. The water inlet and outlet holes 43 on the bearing box 6 are connected to the cooling water pipe, and the coolant in the cooling water pipe cools the cavity of the first cavity 31.

[0056] The shaft inside the bearing housing 6 rotates on two bearings, one in front and one in the back. The bearings are secured by stoppers on the bearing end caps. Each of the front and rear bearing end caps is provided with a circle of through-holes, each circle containing six holes of 9 mm in diameter. The front and rear bearing end caps are bolted to the bearing housing 6 via their respective through-holes. The circle of through-holes on the front bearing end cap is staggered at a 30° angle with the circle of through-holes on the other end caps. A pulley 8 is mounted at the rear of the shaft inside the bearing housing 6. This process improves the cooling and sealing of the bearing housing 6.

[0057] In this embodiment, the bearing housing 6 is made of stainless steel through investment casting, with a double-helix cooling cavity 31 left inside. The housing is then machined integrally using a machining center. A 3% tolerance is permitted to ensure proper cooling water flow and concentricity between the bearing and shaft during installation.

[0058] Example 4

[0059] Based on Example 3, the volute 3 is installed on the mounting end face of the bearing box 6 before the centrifugal impeller 1. The central axis of the air inlet of the collector 2, the central axis of the air inlet of the volute 3 and the central axis of the bearing box 6 are in a straight line, which is called the first central axis. The central axis of the air outlet of the volute 3 is installed on the bearing box 6 at an angle of 90° to the right based on the first central axis.

[0060] like Figure 7 As shown, during the implementation process, the volute 3 has a second water inlet and outlet cavity 32 with an inlet and an outlet. The second water inlet and outlet cavity 32 is a cavity composed of an optimal arc R262.3mm, a cavity spacing of 7.8mm, and a cavity diameter of 4.5mm. The inlet and the outlet extend to the water inlet and outlet holes 43 on the stainless steel volute 3; the water inlet and outlet holes 43 on the volute 3 are connected to the cooling water pipe, and the coolant transported by the cooling water pipe cools the cavity of the second water inlet and outlet cavity 32.

[0061] In this embodiment, the volute 3 is made of stainless steel by melt casting, and a second water inlet and outlet cavity 32 is left inside during casting. The volute 3 is integrally machined by a machining center. The allowable deviation is 3%.

[0062] Example 5

[0063] like Figure 8 and 9 As shown, based on Example 4, the outside of the volute 3 is wrapped with three layers of thermal insulation material 42.

[0064] During the implementation process, the arc surface of the volute 3 is wrapped with three kinds of heat-insulating materials 42, namely polyurethane, aluminum silicate, and thermal insulation rock wool, from the inside to the outside. The innermost layer is 2mm thick polyurethane, and a layer of stainless steel mesh with 0.5mm holes is welded to the volute 3 on the outside of the polyurethane. A layer of 0.1mm fireproof gauze is affixed to the outside of the stainless steel mesh for fixation, and a layer of 2mm aluminum silicate is added to the outside of the fireproof gauze. This is repeated until the last layer of thermal insulation rock wool is used. A layer of stainless steel mesh with 0.5mm holes is affixed to the outside of the stainless steel mesh. The steel mesh is welded and fixed to the volute 3, and a layer of 0.1mm fireproof gauze is affixed to the outside of the aluminum silicate stainless steel mesh for fixation. A layer of 0.5mm hole stainless steel mesh is welded and fixed to the volute 3 on the outside of the thermal insulation rock wool. A layer of 0.1mm fireproof gauze is affixed to the outside of the stainless steel mesh of the thermal insulation rock wool for fixation. A layer of 0.5mm stainless steel arc shell is added to the outside of the fireproof gauze of the thermal insulation rock wool for welding. During welding, the curvature of the front and rear covers of the volute 3 needs to protrude 5mm from one side of the volute for heat dissipation.

[0065] The outside of the volute is protected by multiple layers of thermal insulation materials, including polyurethane, aluminum silicate, and thermal insulation rock wool from the inside to the outside. The middle of each layer is fixed with a stainless steel mesh. The outermost layer of thermal insulation rock wool is welded to the volute through a rolled stainless steel arc plate for fixation. The radius of the two end surfaces of the volute is about 5 mm higher than the radius of the thermal insulation rock wool, and the protruding part is in full contact with the air to facilitate heat dissipation.

[0066] In this embodiment, the volute 3 is covered with different insulation materials, which can cope with a variety of high temperature, fire and other environments, and the protruding arc edge of the volute can play a partial heat dissipation effect and improve the high temperature resistance.

[0067] Example 6

[0068] like Figure 10 As shown, based on Example 1, the collector 2 includes: a conical surface 33 formed by a rolled circle in the middle, which is welded to a front mounting flange 34 and a rear mounting flange 35 respectively welded to the front and rear of the conical surface 33; a spiral guide groove 30 is provided at the inlet conical surface 33 of the collector 2.

[0069] When welding the front mounting flange 34 and the rear mounting flange 35 connected by welding to the front and rear of the conical surface 33, a certain margin is left. The conical surface 33 and the second arc surface 38 of the upper end cover 24 of the centrifugal impeller 1 are machined on a CNC lathe to match the first arc surface 36 of the collector 2. After completion, the spiral guide groove 30 of the collector 2 is machined. The first central axis of the air inlet of the collector 2 is used as the center vector 37. The angle 21° of the center vector 37 is used as the starting point. The 275mm diameter front mounting flange 34 is used as the reference. The center vector 37 of the collector 2 is used to start the machining to the starting position of the R angle of the collector. The starting position of the R angle of the collector is the intersection 39 of the collector 2 and the copper sheet 22. The arc groove with a radius of R7.2mm and a groove pitch of 16.7mm is machined to form the guide groove 30. The center vector 37 and the first central axis are aligned. Here, the copper sheet 22 is mounted on the current collector 2 , and the current collector 2 and the copper sheet 22 form a junction 39 .

[0070] In addition, the collector 2 is mounted on the volute 3 by bolts through holes with a hole center distance of 415 mm.

[0071] In this embodiment, the guide grooves 30 of the collector 2 can have a certain rectifying effect on the airflow, making the airflow smoother when passing through the tapered opening of the collector, thereby reducing a certain amount of wind loss.

[0072] Example 7

[0073] like Figure 11As shown, on the basis of Example 6, the first arc surface 36 of the collector 2 cooperates with the second arc surface 38 of the upper end cover 24 of the adjacent centrifugal impeller 1.

[0074] During implementation, the collector 2 is mounted on the copper sheet 22 at a diameter of 235 mm, forming an intersection 39 between the collector 2 and the copper sheet 22. This intersection 39 is then used as a starting point. A CNC lathe is used to machine an irregular arc consisting of an R22.3 mm arc and an R24.1 mm arc to form a first arc surface 36 of the collector 2. This first arc surface 36 of the collector 2 mates with a second arc surface 38 of R11.8 mm on the upper end cover 24 of the centrifugal impeller. The clearance 23 between the first arc surface 36 of the collector 2 and the second arc surface 38 of the upper end cover 24 of the centrifugal impeller is 3 mm, with an allowable floating deviation of 3%. The first arc surface 36 of the collector 2 that mates with the second arc surface 38 of the upper end cover 24 is welded to the copper 22 and the stainless steel collector 2 for explosion-proofing.

[0075] In this embodiment, the gap 23 between the centrifugal impeller 1 and the collector 2 is very important. If the distance is too close, it may cause the shell to rub and sparks to appear, which will affect the explosion-proof performance of the entire machine. If the distance is too far, the gap becomes larger, which will lead to a decrease in aerodynamic performance and failure to discharge high-temperature gas out of the volute 3 in time.

[0076] Example 8

[0077] like Figure 11 As shown, based on Example 7, the first arc surface 36 of the current collector 2 that mates with the second arc surface 38 of the upper end cover 24 of the centrifugal impeller 1 is explosion-proofed by welding copper 22 to the stainless steel current collector 2. On the first arc surface 36 of the stainless steel current collector 2 where it mates with the centrifugal impeller, 1 mm copper material is rolled into a copper arc with an R24 diameter and a copper arc with an R28.5 diameter. These two copper arcs are then welded to the stainless steel current collector 2 to form a single unit.

[0078] During the implementation process, it is necessary to use the surface of the collector 2 with a diameter of 235mm, that is, the junction 39 between the collector 2 and the copper sheet 22 as the starting point, and the subsequent 3mm thick first arc surface 36 needs to be processed to reduce the thickness of 3mm to 2mm during processing. The copper circle is embedded in the groove and a single-side step of 0.5mm is left to form a groove. The cross-section of the groove is a slightly curved concave shape. The copper sheet 22 is embedded and installed in the groove. The copper sheet 22 is connected to the collector 2 by argon arc welding, and finally processed to ensure the accuracy of the curvature.

[0079] In this embodiment, two sections of copper sheets 22 are welded to the first arc surface 36 of the current collector 2 at the fitting gap 23 between the arc surface 36 of the current collector 2 and the second arc surface 38 of the centrifugal impeller 1, so that the rotation fitting gap 23 between the current collector 2 and the centrifugal impeller 1 is prevented from generating sparks between the same metals by the mutual cooperation of the stainless steel and copper materials.

[0080] Example 9

[0081] On the basis of Example 1, the motor and the bearing box are connected and driven by a pulley set, and the motor terminal box 4 and the motor housing 5 are integrally cast.

[0082] During the implementation process, the terminal box 4 of the motor 5 and the housing of the motor 5 are connected into one piece by using a melt casting method, and the gap between the motor housing 5 and the terminal box 4 is eliminated. During casting, there is a third water inlet and outlet cavity with an inlet and an outlet inside the motor housing. The third water inlet and outlet cavity is a spiral cavity with a diameter of 131 mm, a cavity spacing of 8.3 mm, and a cavity diameter of 4 mm. The inlet and outlet extend to the water inlet and outlet holes 43 on the motor housing. The water inlet and outlet holes 43 on the motor housing are connected to the cooling water pipe, and the cooling liquid is transported through the cooling water pipe to cool the cavity of the third water inlet and outlet cavity.

[0083] In this embodiment, the motor housing 5 and the junction box 4 are integrally cast, which can effectively reduce the risk of electric leakage and improve its explosion-proof performance. The water cooling method can reduce the surface temperature of the motor to a limited extent.

Claims

1. A centrifugal fan, characterized in that: include: Collector, centrifugal impeller, volute, bearing box and motor, among which, The air inlet end of the centrifugal impeller is provided with the collector, and the outer shell of the centrifugal impeller is provided with a volute; The rear end face of the volute is connected to the end face of the bearing box, the lower end face of the volute is connected to the bottom plate, the front end face of the volute is connected to the collector, and the centrifugal impeller is connected to the shaft of the bearing box; The shaft of the bearing box and the shaft of the motor are connected through a pulley, the bearing box is driven by the motor through the pulley, and the outside of the pulley is protected by a protective cover; water inlet and outlet holes are provided on the volute, the motor housing of the motor and the bearing box.

2. The centrifugal fan according to claim 1, characterized in that: The centrifugal impeller comprises: An upper end cover and a chassis with a blade group, wherein a plurality of blade groups are evenly spaced on the chassis of the centrifugal impeller, wherein three blades of different lengths and spaced apart constitute a blade group, and each blade group is composed of three blade units of different shapes. The length and curvature of the blade unit of each shape are different, and the thickness of each blade unit gradually increases and then decreases from the tip to the tail. The tip of each blade unit is flush with the outer diameter of the chassis, and the fillet ratio of the tip to the tail of each blade unit is 2:1, wherein the two sides of each blade unit are respectively connected to the upper end cover and the chassis, and each blade unit is arranged between the upper end cover and the chassis; the tip of the blade on the chassis side is close to the outer ring of the chassis, and the tail of the blade on the chassis side is close to the inner ring of the chassis, wherein the outer ring of the chassis is the outer diameter of the centrifugal impeller, and the inner ring of the chassis is the inner diameter of the centrifugal impeller.

3. The centrifugal fan according to claim 2, characterized in that: From the longest blade unit to the shortest blade unit in each blade group, the fillet sizes of the blade tail in each blade group are R0.8mm, R0.87mm and R0.95mm respectively, and the number of blade units with three different shapes is the same.

4. The centrifugal fan according to claim 3, characterized in that: The gap between two adjacent blade units of each blade group on the centrifugal impeller forms an air duct, with air discharged from the blade tip of the outer ring of the chassis and air taken in from the blade tail of the inner ring of the chassis; the length ratios of the three blade units with different shapes in each blade group are 6:5:3 respectively, and the projected angles of the inlet leading edge of the blade units with three different shapes and the outlet tail edge of the blade units on the vertical plane are 88.7°, 50.2° and 35.6° respectively, wherein the inlet leading edge of the blade unit is a circle formed by the blade tails of all blade units with the same shape; the outlet tail edge of the blade unit is a circle formed by the blade tips of all blade units with the same shape.

5. The centrifugal fan according to claim 1, characterized in that: The interior of the bearing housing has two symmetrical sets of first water inlet and outlet cavities, each with a diameter of 100 mm, a cavity spacing of 10.3 mm, and a cavity diameter of 4 mm. The spiral cavity has a total of 9 turns and extends to the water inlet and outlet holes on the bearing housing. The water inlet and outlet holes on the bearing housing are connected to the cooling water pipe, and the coolant in the cooling water pipe cools the first cavity. The interior of the volute has a second water inlet and outlet cavity with an inlet and an outlet. The second water inlet and outlet cavity has a preferred arc R262.3mm, a cavity spacing of 7.8mm, and a cavity diameter of 4.5mm. The inlet and outlet extend to the water inlet and outlet holes on the stainless steel volute; the water inlet and outlet holes on the volute are connected to the cooling water pipe, and the coolant transported by the cooling water pipe cools the second water inlet and outlet cavity; The junction box of the motor is connected to the motor casing as an integral whole. There is no gap between the motor casing and the junction box. A third water inlet and outlet cavity with one inlet and one outlet is provided inside the motor casing. The third water inlet and outlet cavity is a spiral cavity with a diameter of 131 mm, a cavity spacing of 8.3 mm, and a cavity diameter of 4 mm. The inlet and outlet extend to the water inlet and outlet holes on the motor casing. The water inlet and outlet holes on the motor casing are connected to the cooling water pipe, and the coolant is transported through the cooling water pipe to cool the third water inlet and outlet cavity.

6. The centrifugal fan according to claim 1, characterized in that: The arc surface of the volute is wrapped with three kinds of heat-insulating materials from the inside to the outside, namely polyurethane, aluminum silicate, and thermal insulation rock wool, among which the innermost layer is polyurethane, and a layer of stainless steel mesh is arranged on the outside of the polyurethane and welded and fixed on the volute, and a layer of fireproof gauze is attached to the outside of the stainless steel mesh; a layer of aluminum silicate is arranged on the outside of the fireproof gauze outside the stainless steel mesh of polyurethane, and a layer of stainless steel mesh is arranged on the outside of the aluminum silicate and welded and fixed on the volute, and a layer of fireproof gauze is attached to the outside of the stainless steel mesh of aluminum silicate; a layer of thermal insulation rock wool is arranged on the outside of the fireproof gauze outside the stainless steel mesh of aluminum silicate, and a layer of stainless steel mesh is arranged on the outside of the thermal insulation rock wool and welded and fixed on the volute, a layer of fireproof gauze is attached to the outside of the stainless steel mesh of thermal insulation rock wool, and a layer of stainless steel arc shell is welded to the outside of the fireproof gauze of the thermal insulation rock wool, and a layer of stainless steel arc shell is welded to the outside of the fireproof gauze of the thermal insulation rock wool, and the curvature of the front and rear covers of the volute protrudes from one side of the volute.

7. The centrifugal fan according to claim 1, characterized in that: The collector is also provided with a first arc surface that cooperates with the second arc surface of the upper end cover of the centrifugal impeller. A copper sheet is installed on the first arc surface. The first arc surface is an irregular arc composed of two arcs starting from the junction of the collector and the copper sheet installed on the collector. A matching gap is left between the first arc surface of the collector and the second arc surface of the upper end cover of the centrifugal impeller.

8. The centrifugal fan according to claim 7, characterized in that: The collector is formed into two copper arcs by rolling copper material on the first arc surface where it cooperates with the second arc surface of the upper end cover of the centrifugal impeller. The two copper arcs are welded to the stainless steel collector to form a whole.

9. The centrifugal fan according to claim 7, characterized in that: The central axis of the air inlet of the collector, the central axis of the air inlet of the volute and the central axis of the bearing box are in a straight line, called the first central axis. The central axis of the air outlet of the volute is installed on the bearing box at an angle of 90° to the right based on the first central axis.

10. The centrifugal fan according to claim 9, characterized in that: The current collector includes: a conical surface formed by rolling in the middle, which is welded to the front mounting flange and the rear mounting flange respectively connected to the front and rear of the conical surface; wherein, A spiral guide groove is provided at the conical surface of the inlet of the collector, wherein the guide groove takes the first central axis of the air inlet of the collector as the central vector, starts at an angle of 21° along the central vector, and takes the front mounting flange with a diameter of 275mm as the reference. It is processed along the central vector of the collector to the starting position of the R angle of the collector. The starting position of the R angle is the junction of the collector and the copper sheet. The processed circle has a radius of R7.2mm and a groove pitch of 16.7mm.

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