An explosion-proof centrifugal fan

Abstract

The present invention relates to an explosion-proof centrifugal fan, comprising an impeller, a casing and a pressure plate, the impeller comprising a base plate, blades and a connecting shaft, the connecting shaft being arranged at the axis center of the base plate, and a plurality of backward-inclined blades being fixedly connected to the base plate and the connecting shaft; compared with the prior art, the matching pressure plate and impeller in this explosion-proof centrifugal fan can increase the diversion effect, reduce the intake noise and reduce vortex while increasing the airflow; the backward-inclined arc-shaped and lubricated blades can reduce the airflow resistance, make the movement smoother, and reduce the impact of the airflow on the impeller and the casing, thereby achieving the purpose of noise reduction; at the same time; the aluminum casing, impeller and pressure plate can effectively achieve an explosion-proof effect, and the air inlet with a draft design can have a rectifying effect, thereby achieving the purpose of improving the total pressure and static pressure of this explosion-proof centrifugal fan.

Description

Technical Field

[0001] The present invention relates to the technical field of centrifugal fans, and in particular to an explosion-proof centrifugal fan. Background Art

[0002] Conventional fan blades are mostly made of iron, stainless steel and other materials. When the fan blades rotate at high speed, they may rub against the outer casing, generating sparks during the friction process. If the fan is used in situations where there are flammable and explosive risks, there is a risk of explosion.

[0003] Judging from the current social development trend, the environments where explosions may occur will inevitably increase, such as: flammable gases, dust environments, refineries, petrochemical plants, gas stations, gas stations, etc. Therefore, the demand for using matching fully explosion-proof centrifugal fans as ventilation equipment will increase, and there is a great development prospect.

[0004] The existing explosion-proof centrifugal fan generates relatively loud noise during operation, which will cause certain noise pollution. Therefore, there is a need for an explosion-proof centrifugal fan with relatively low noise. Summary of the Invention

[0005] The object of the present invention is to provide an explosion-proof centrifugal fan, aiming to solve the problem of high operating noise of existing explosion-proof centrifugal fans.

[0006] In order to achieve the above-mentioned purpose, the present invention provides an explosion-proof centrifugal fan, including an impeller, a casing and a pressure plate, the impeller including a base plate, blades and a connecting shaft, the connecting shaft is arranged at the axis of the base plate, and a plurality of backward-inclined blades are fixedly connected to the base plate and the connecting shaft; the blades include a bottom edge connected to the base plate and a top edge away from the base plate, the top edge includes an air inlet oblique edge whose inner end is connected to the connecting shaft and continuously extends outward and upward, the outer end of the air inlet oblique edge is connected to an air guide oblique edge that continuously extends outward and downward, an air outlet straight edge is connected between the outer end of the air guide oblique edge and the outer end of the bottom edge, and the air outlet straight edge is perpendicular to the base plate; the lowest end height of the air inlet oblique edge is consistent with the height of the connecting shaft; the projection of the blade on the base plate includes a projection circle away from the connecting shaft The arc segment and the projected straight line segment close to the connecting axis, the projections of the air inlet bevel and the air guide bevel are contained in the projected straight line segment, the projections of other parts of the air guide bevel are contained in the projected circular arc segment, and the projected straight line segment is tangent to the projected circular arc segment; the casing includes two structurally symmetrical shells, the symmetry surfaces of the two shells are their connecting surfaces, mounting positions and air outlets are provided on the shells, a pressure plate is provided on the mounting position on one side, the pressure plate is embedded in the casing, and a conical air inlet is provided on the pressure plate, and the air inlet part extends into the casing; a gap is left between the impeller and the pressure plate, the bottom surface of the pressure plate is parallel to the air guide bevel, and the distance H3 between the two is 1.2-1.3mm; the casing, impeller and pressure plate are all made of aluminum.

[0007] Furthermore, the height H1 of the inner cavity formed by the shell is 189.5-190.5 mm, the shortest distance H3 from the bottom edge of the blade to the shell is 35.5-36.2 mm, the height H6 between the intersection of the air guide oblique edge and the air inlet oblique edge and the bottom plate is 115-115.5 mm, the height H7 of the air outlet straight edge is 86.5-87.5 mm, and the angle ∠5 formed by the air outlet straight edge and the air guide oblique edge is 104.5-105.5 degrees.

[0008] Furthermore, the length L1 of the projected straight line segment is 72-73 mm, the central arc length ⌒1 of the projected arc segment is 107.2-109.2 mm, and the radius R1 of the projected arc segment is 105.5-106.5 mm; the air inlet angle θ1 formed by the inner end of the projected straight line segment is 51-53 degrees, and the air outlet angle θ2 formed by the outer end of the projected arc segment is 52-54 degrees.

[0009] Furthermore, the outer circumference R2 formed by the outer ends of all blades is 204.5-05.5 mm, the bottom plate thickness H5 is 6.7-7.2 mm; the top radius R3 of the connecting shaft is 36.5-37.5 mm and the height H4 is 47.5-48.5 mm.

[0010] Furthermore, the profile of the casing is surrounded by the first arc segment, the second arc segment, the third arc segment, the fourth arc segment, the fifth arc segment and the diffuser segment. The first arc segment is tangent to the second arc segment, the second arc segment is tangent to the third arc segment, the third arc segment is tangent to the fourth arc segment, the fourth arc segment is tangent to the fifth arc segment, and the fifth arc segment is tangent to the diffuser segment. A rectangular coordinate system is established with the center of the installation position of the casing as the coordinate origin O. The coordinates of the center O1 of the first arc segment are (22.7, 5), the radius R4 is 233.3-233.6 mm, and the central angle ∠1 is 17.5-18.5 degrees. The coordinates of the center O2 of the second arc segment are (4, 8), the radius R5 is The center O3 of the third arc segment is 252-253mm, and the central angle ∠2 is 90.5-91.5 degrees; the center O3 of the third arc segment is (-1, -9), the radius R6 is 269-270mm, and the central angle ∠3 is 88.5-89.5 degrees; the center O4 of the fourth arc segment is (21, -10), the radius R7 is 291-292mm, and the central angle ∠4 is 92.5-93.5 degrees; the center O5 of the fifth arc segment is (18.5, 1579.5), the radius R8 is 1880-1881mm, and the central angle corresponding to the fifth arc segment is 1.5-2.5 degrees; the length L2 of the diffuser section is 151.5-152.5mm.

[0011] Furthermore, the outer side of the pressure plate and the air inlet both adopt a draft design, and the draft angle is 3 degrees.

[0012] Furthermore, a motor mounting plate is installed on a mounting position on the housing away from the side where the pressure plate is provided, and a driving motor for driving the impeller is installed on the motor mounting plate.

[0013] Furthermore, the pressure plate and the casing are made of high-strength ADC12 aluminum alloy, and the impeller is made of high-strength 6061 (T6) aluminum.

[0014] Furthermore, the thickness of the blade at one end close to the base plate is slightly greater than that at one end away from the base plate.

[0015] The explosion-proof centrifugal fan provided by the present invention has a matching pressure plate and impeller that can increase the diversion effect compared to the existing technology. While increasing the airflow, it can also reduce the intake noise and reduce vortexes; the backward-inclined arc-shaped and lubricated blades can reduce the airflow resistance, making its movement smoother and reducing the impact of the airflow on the impeller and the casing, thereby achieving the purpose of noise reduction; at the same time, the aluminum casing, impeller and pressure plate can effectively achieve an explosion-proof effect, and the air inlet with a draft design can have a rectifying effect, thereby achieving the purpose of improving the total pressure and static pressure in this explosion-proof centrifugal fan. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a stereoscopic view of the present invention;

[0017] Figure 2 is an exploded view of the present invention;

[0018] Figure 3 It is a cross-sectional view of the present invention with some components hidden;

[0019] Figure 4 is a three-dimensional view of the housing of the present invention;

[0020] Figure 5 It is a structural schematic diagram of the casing of the present invention;

[0021] Figure 6 is a three-dimensional view of the impeller of the present invention;

[0022] Figure 7 is a cross-sectional view of the impeller of the present invention;

[0023] Figure 8 is a top view of the impeller of the present invention;

[0024] Figure 9 It is an expanded view of the blade in the present invention;

[0025] Figure 10 is a three-dimensional cross-sectional view of the pressure plate of the present invention;

[0026] Figure 11 It is a cross-sectional view of the pressure plate of the present invention.

[0027] Description of reference numerals:

[0028] Among them: 1. Casing; 11. Air outlet; 12. Mounting position; 2. Impeller; 20. Blades; 21. Bottom plate; 22. Connecting shaft; 23. Air inlet bevel; 24. Air guide bevel; 25. Air outlet straight edge; 3. Pressure plate; 31. Air inlet; 4. Motor mounting plate; 5. Drive motor. DETAILED DESCRIPTION

[0029] The present invention is described in detail below with reference to specific embodiments.

[0030] In the present invention, unless otherwise expressly specified and limited, when terms such as "set on", "connected", and "connected" appear, these terms should be understood in a broad sense. For example, they can be fixedly connected, detachably connected, or integrally connected; they can be directly connected or connected through one or more intermediate media. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances. The directional words that appear in the present invention are to better illustrate the characteristics of the features and the relationship between the features. It should be understood that when the placement direction of the present invention changes, the characteristics of the features and the direction of the relationship between the features also change accordingly. Therefore, the directional words do not constitute an absolute limitation on the characteristics of the features and the relationship between the features in space, but only play a relative limitation role.

[0031] like Figures 1 to 11 As shown, an explosion-proof centrifugal fan includes an impeller 2, a casing 1, and a pressure plate 3. The impeller 2 includes a base plate 21, blades 20, and a connecting shaft 22. The connecting shaft 22 is disposed at the axis of the base plate 21. A plurality of backward-inclined blades 20 are fixedly connected to the base plate 21 and the connecting shaft 22. The blades 20 are fixed to the base plate 21 and the connecting shaft 22 by welding. The backward-inclined blades 20 generate less noise during operation, and the efficiency, flow rate, and air pressure are relatively stable.

[0032] The blade 20 includes a bottom edge connected to the bottom plate 21 and a top edge away from the bottom plate 21. The top edge includes an air inlet oblique edge 23 whose inner end is connected to the connecting shaft 22 and continuously extends outward and upward. The outer end of the air inlet oblique edge 23 is connected to an air guide oblique edge 24 that continuously extends outward and downward. An air outlet straight edge 25 is connected between the outer end of the air guide oblique edge 24 and the outer end of the bottom edge, and the air outlet straight edge 25 is perpendicular to the bottom plate 21. The height of the lowest end of the air inlet oblique edge 23 is consistent with the height of the connecting shaft 22, and the thickness of the blade 20 at the end close to the bottom plate 21 is slightly greater than the thickness of the blade 20 at the end away from the bottom plate 21.

[0033] like Figure 8As shown, the projection of the blade 20 on the base plate 21 includes a projected arc segment away from the connecting axis 22 and a projected straight line segment close to the connecting axis 22. The projections of the air inlet bevel 23 and the air guide bevel 24 are included in the projected straight line segment, and the projections of other parts of the air guide bevel 24 are included in the projected arc segment. The projected straight line segment is tangent to the projected arc segment.

[0034] In this embodiment, the casing 1 includes two symmetrical shells, the symmetrical surfaces of the two shells are their connecting surfaces, and the shells are provided with mounting positions 12 and air outlets 11. A pressure plate 3 is provided on the mounting position 12 on one side, and the pressure plate 3 is embedded in the casing 1. A conical air inlet 31 is provided on the pressure plate 3, and the air inlet 31 partially extends into the casing 1; a gap is left between the impeller 2 and the pressure plate 3. The bottom surface of the pressure plate 3 is parallel to the wind guide bevel 24, and the spacing H2 between the two is 1.2-1.3mm. The specific gap formed by the combination of the two can effectively reduce the guide section. The outer side of the pressure plate 3 and the air inlet 31 are both designed with a draft, and the draft angle is 3 degrees. The air inlet 31 at this angle is not only convenient for casting demolding, but also has a rectifying effect, improving the smoothness of the air flow, and achieving the purpose of increasing the total pressure and static pressure.

[0035] In this embodiment, the casing 1, impeller 2 and pressure plate 3 are all made of aluminum. The pressure plate 3 and casing 1 are both made of high-strength ADC12 aluminum alloy, and the impeller 2 is made of high-strength 6061 (T6) aluminum. Aluminum products are relatively soft, and the energy generated during friction will be directly consumed in metal deformation. At the same time, only a small amount of particles will fall off, making it difficult to generate sparks, thereby achieving an explosion-proof effect.

[0036] In this embodiment, the length L1 of the projected straight line segment is 72-73 mm, the central arc length ⌒1 of the projected arc segment is 107.2-109.2 mm, and the radius R1 of the projected arc segment is 105.5-106.5 mm; the air inlet angle θ1 formed by the inner end of the projected straight line segment is 51-53 degrees, and the air outlet angle θ2 formed by the outer end of the projected arc segment is 52-54 degrees.

[0037] In this embodiment, the radius R2 of the outer circle surrounded by the outer ends of all the blades is 204.5-205.5 mm, the thickness H5 of the bottom plate 21 is 6.7-7.2 mm, and a boss is provided at the bottom of the bottom plate 21; the radius R3 of the top end of the connecting shaft 22 is 36.5-37.5 mm and the height H4 is 47.5-48.5 mm; a through hole is also provided on the bottom plate 21 to pass through the connecting shaft 22 and the boss.

[0038] In this embodiment, if Figure 3 As shown, the height H1 of the inner cavity formed by the shell is 189.5-190.5 mm, and the shortest distance H3 from the bottom edge of the blade 20 to the shell is 35.5-36.2 mm. Figure 7 and Figure 9 As shown, the height H6 between the intersection of the air guide oblique edge 24 and the air inlet oblique edge 23 and the bottom plate is 115-115.5 mm, the height H7 of the air outlet straight edge 25 is 86.5-87.5 mm, and the angle ∠5 formed by the air outlet straight edge 25 and the air guide oblique edge 24 is 104.5-105.5 degrees.

[0039] In this embodiment, if Figure 5 As shown, the profile of the casing 1 is surrounded by a first arc segment, a second arc segment, a third arc segment, a fourth arc segment, a fifth arc segment and a diffuser segment. The first arc segment is tangent to the second arc segment, the second arc segment is tangent to the third arc segment, the third arc segment is tangent to the fourth arc segment, the fourth arc segment is tangent to the fifth arc segment, and the fifth arc segment is tangent to the diffuser segment. A rectangular coordinate system is established with the center of the mounting position 12 of the housing 1 as the coordinate origin O. The coordinates of the center O1 of the first arc segment are (22.7, 5), the radius R4 is 233.3-233.6 mm, and the central angle ∠1 is 17.5-18.5 degrees; the coordinates of the center O2 of the second arc segment are (4, 8), the radius R5 is 252-253 mm, and the central angle ∠2 is 90.5-91.5 degrees; the coordinates of the center O3 of the third arc segment are (-1, -9), the radius R6 is 269-270 mm, and the central angle ∠3 is 88.5-89.5 degrees; the coordinates of the center O4 of the fourth arc segment are (21, -10), the radius R7 is 291-292 mm, and the central angle ∠4 is 92.5-93.5 degrees; the coordinates of the center O5 of the fifth arc segment (not shown in the figure) are (18.5, 1579.5), the radius R8 is 1880-1881 mm, and the central angle corresponding to the fifth arc segment is 1.5-2.5 degrees; the length L2 of the diffuser section is 151.5-152.5 mm.

[0040] In this embodiment, a motor mounting plate 4 is mounted on a mounting position 12 on the housing 1 away from the pressure plate 3 , and a driving motor 5 for driving the impeller 2 is mounted on the motor mounting plate 4 .

[0041] Compared with the prior art, the gap of a specific size formed between the pressure plate 3 and the impeller 2 in the present invention can increase the guiding effect, reduce the intake noise and reduce vortex while increasing the airflow; the backward arc-shaped and lubricated blades 20 can reduce the airflow resistance, make its movement smoother, and reduce the impact of the airflow on the impeller 2 and the casing 1, so as to achieve the purpose of noise reduction; at the same time, the aluminum casing 1, impeller 2 and pressure plate 3 can effectively achieve an explosion-proof effect, and the air inlet 31 with a draft design can have a rectifying effect, thereby achieving the purpose of improving the total pressure and static pressure of the explosion-proof centrifugal fan.

[0042] In the absence of conflict, the above embodiments and features therein may be combined with each other.

[0043] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. An explosion-proof centrifugal fan, comprising an impeller (2), a housing (1) and a pressure plate (3), characterized in that: The impeller (2) comprises a base plate (21), blades (20) and a connecting shaft (22); the connecting shaft (22) is arranged at the axis of the base plate (21); and a plurality of backward-inclined blades (20) are fixedly connected to the base plate (21) and the connecting shaft (22); The blade (20) includes a bottom edge connected to the bottom plate (21) and a top edge away from the bottom plate (21); the top edge includes an air inlet oblique edge (23) whose inner end is connected to the connecting shaft (22) and continuously extends outward and upward; the outer end of the air inlet oblique edge (23) is connected to an air guide oblique edge (24) that continuously extends outward and downward; an air outlet straight edge (25) is connected between the outer end of the air guide oblique edge (24) and the outer end of the bottom edge; the air outlet straight edge (25) is perpendicular to the bottom plate (21); the bottom end of the air inlet oblique edge (23) is at the same height as the connecting shaft (22); The projection of the blade (20) on the base plate (21) includes a projection arc segment away from the connecting shaft (22) and a projection straight line segment close to the connecting shaft (22); the projections of the air inlet oblique edge (23) and the air guide oblique edge (24) are included in the projection straight line segment; the projections of other parts of the air guide oblique edge (24) are included in the projection arc segment; the projection straight line segment is tangent to the projection arc segment; The casing (1) comprises two symmetrical shells, the symmetrical surfaces of the two shells being their connecting surfaces, the shells being provided with mounting positions (12) and air outlets (11), a pressing plate (3) being provided on the mounting position (12) on one side, the pressing plate (3) being embedded in the casing (1), and a conical air inlet (31) being provided on the pressing plate (3), the air inlet (31) partially extending into the casing (1); a gap being left between the impeller (2) and the pressing plate (3), the bottom surface of the pressing plate (3) being parallel to the wind guide bevel (24), and the spacing H3 between the two being 1.2-1.3 mm; The casing (1), impeller (2) and pressure plate (3) are all made of aluminum; The height H1 of the inner cavity formed by the shell is 189.5-190.5 mm, the shortest distance H3 from the bottom edge of the blade (20) to the shell is 35.5-36.2 mm, the height H6 between the intersection of the wind guide oblique edge (24) and the wind inlet oblique edge (23) and the bottom plate is 115-115.5 mm, the height H7 of the wind outlet straight edge (25) is 86.5-87.5 mm, and the angle ∠5 formed by the wind outlet straight edge (25) and the wind guide oblique edge (24) is 104.5-105.5 degrees; The length L1 of the projected straight line segment is 72-73 mm, the central arc length ⌒1 of the projected arc segment is 107.2-109.2 mm, and the radius R1 of the projected arc segment is 105.5-106.5 mm; the air inlet angle θ1 formed by the inner end of the projected straight line segment is 51-53 degrees, and the air outlet angle θ2 formed by the outer end of the projected arc segment is 52-54 degrees; The radius R2 of the outer circle formed by the outer ends of all blades is 204.5-205.5 mm, and the thickness H5 of the bottom plate (21) is 6.7-7.2 mm; the radius R3 of the top end of the connecting shaft (22) is 36.5-37.5 mm and the height H4 is 47.5-48.5 mm; The profile of the casing (1) is formed by a first arc segment, a second arc segment, a third arc segment, a fourth arc segment, a fifth arc segment and a diffuser segment. The first arc segment is tangent to the second arc segment, the second arc segment is tangent to the third arc segment, the third arc segment is tangent to the fourth arc segment, the fourth arc segment is tangent to the fifth arc segment, and the fifth arc segment is tangent to the diffuser segment. A rectangular coordinate system is established with the center of the installation position (12) of the casing (1) as the coordinate origin O. The center O1 of the first arc segment has a coordinate of (22.7, 5), a radius R4 of 233.3-233.6 mm, and a center angle ∠1 of 17.5-18.5 degrees. The center O2 of the second arc segment has a coordinate of (4, 8), a radius R 5 is 252-253mm, and the central angle ∠2 is 90.5-91.5 degrees; the coordinates of the center O3 of the third arc segment are (-1, -9), the radius R6 is 269-270mm, and the central angle ∠3 is 88.5-89.5 degrees; the coordinates of the center O4 of the fourth arc segment are (21, -10), the radius R7 is 291-292mm, and the central angle ∠4 is 92.5-93.5 degrees; the coordinates of the center O5 of the fifth arc segment are (18.5, 1579.5), the radius R8 is 1880-1881mm, and the central angle corresponding to the fifth arc segment is 1.5-2.5 degrees; the length L2 of the diffuser section is 151.5-152.5mm; The outer side of the pressing plate (3) and the air inlet (31) both adopt a draft design, and the draft angle is 3 degrees.

2. The explosion-proof centrifugal fan according to claim 1, characterized in that: A motor mounting plate (4) is mounted on a mounting position (12) on the housing (1) away from the side where the pressure plate (3) is arranged. The motor mounting plate (4) is mounted with a driving motor (5) for driving the impeller (2).

3. The explosion-proof centrifugal fan according to claim 1, characterized in that: The pressure plate (3) and the casing (1) are both made of high-strength ADC12 aluminum alloy, and the impeller (2) is made of high-strength 6061 (T6) aluminum.

4. The explosion-proof centrifugal fan according to claim 1, characterized in that: The thickness of the blade (20) at one end close to the bottom plate (21) is slightly greater than that at one end of the blade (20) away from the bottom plate (21).

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