A multi-blade centrifugal fan with high static pressure and low noise

Abstract

The present invention relates to the field of centrifugal fans, and in particular to a multi-blade centrifugal fan with high static pressure and low noise, comprising a volute, an impeller and a collector arranged in the inner cavity of the volute, the collector being coaxially arranged with the impeller, the impeller comprising a front disc and a rear disc, the middle portion of the front disc being provided with an air intake, and the rear disc being provided with a plurality of blades arranged in an array around the impeller; the profile of the volute being an unequally spaced square spiral, the volute tongue of the volute being provided with an outwardly expanding structure, the outward expansion angle ∠10 of the volute tongue being 26.6°-27.4°; the diameter of the outer circle formed by the outer ends of all the impeller blades being φ3, the vertical spacing between the impeller and the volute tongue being L5, the ratio of L5 to φ3 being 0.147-0.15; an axial gap L13 being provided between the collector and the impeller, the ratio of L13 to φ3 being 0.02-0.025. The multi-blade centrifugal fan with high static pressure and low noise of the present invention has the effects of high efficiency, high static pressure and low noise.

Description

Technical Field

[0001] The present invention relates to the field of centrifugal fan industry, and in particular to a multi-blade centrifugal fan with high static pressure and low noise. Background Art

[0002] Multi-blade centrifugal fans are primarily used in equipment support, air conditioning units, and ventilation and fume extraction applications in hotels and restaurants. As society's demands for fan performance and environmental protection continue to rise, the performance of multi-blade centrifugal fans is also improving. Static pressure is a key performance indicator for multi-blade centrifugal fans. Static pressure refers to the ability of fluid to overcome pipe resistance when flowing through a pipe. The higher the static pressure, the greater the flow rate of air the system can transport, thereby increasing overall air volume. However, current, conventional multi-blade centrifugal fans generally suffer from insufficient static pressure, low efficiency, and excessive noise, making them difficult to meet the demands of society and users.

[0003] Therefore, it is urgent to develop a multi-blade centrifugal fan with high efficiency, high static pressure ratio and low noise. Summary of the Invention

[0004] The purpose of the present invention is to provide a multi-blade centrifugal fan with high static pressure and low noise, aiming to solve the problems of insufficient static pressure, low efficiency and excessive noise commonly found in multi-blade centrifugal fans in the prior art.

[0005] To achieve the above-mentioned objectives, a high static pressure, low noise multi-blade centrifugal fan is provided, comprising a volute, an impeller disposed in an inner cavity of the volute, and a flow collector, the flow collector being coaxially arranged with the impeller, the impeller comprising a front disc and a rear disc, the front disc being provided with an air intake in the middle thereof, and the rear disc being provided with a plurality of blades arranged in an array around the front disc; the profile of the volute being an unequally spaced square spiral, the volute tongue of the volute being provided with an outwardly expanding structure, the outward expansion angle ∠10 of the volute tongue being 26.6°-27.4°;

[0006] The diameter of the outer circle formed by the outer ends of all blades of the impeller is φ3, the vertical distance between the impeller and the volute tongue is L5, and the ratio of L5 to φ3 is 0.147-0.15;

[0007] An axial gap L13 is provided between the collector and the impeller, and the ratio of L13 to φ3 is 0.02-0.025.

[0008] Furthermore, φ3 is 500 mm, ∠10 is 27°, L5 is 73.7 mm, and L13 is 10 mm;

[0009] The inner diameter φ4 of the circle formed by the inner ends of all the blades of the impeller is 400mm-402mm, the diameter φ5 of the air suction port is 414mm-416mm, and the width L3 of the impeller is 203.5mm-205.5mm;

[0010] The blade is an arc-shaped sheet metal blade, the radius R2 of the blade is 30mm-32mm and the central angle ∠2 is 109.2°-110.8°, the inlet angle ∠3 when the blade is installed is 59.3°-60.7°, and the outlet angle ∠4 when the blade is installed is 164°-166°;

[0011] The number of blades is 42.

[0012] Furthermore, the impeller further includes a wheel disc and four impeller support rods, the wheel disc is arranged in the middle of the rear disc, one end of the impeller support rod is fixedly connected to the wheel disc, and the other end of the impeller support rod is fixedly connected to the front disc;

[0013] The impeller support rods include a first impeller support rod, a second impeller support rod, a third impeller support rod, and a fourth impeller support rod. On the projection surface of the rear disc, the connection points of the four impeller support rods and the disc are evenly distributed on a cocircle, and the diameter φ6 of the circle is 164mm-166mm. The first impeller support rod and the third impeller support rod are parallel, and the second impeller support rod and the fourth impeller support rod are parallel.

[0014] The connection point between the first support rod and the wheel disc and the connection point between the third support rod and the wheel disc are connected to form a first connection line passing through the center of the impeller, and the connection point between the second support rod and the wheel disc and the connection point between the fourth support rod and the wheel disc are connected to form a second connection line passing through the center of the impeller. The angle between the first support rod and the second connection line is ∠5, the angle between the third support rod and the second connection line is ∠7, the angle between the second support rod and the first connection line is ∠6, and the angle between the fourth support rod and the first connection line is ∠8. ∠5 and ∠7 are equal and are both 23.5°-24.5°, and ∠6 and ∠8 are equal and are both 20.5°-21.5°.

[0015] Furthermore, φ4 is 401 mm, φ5 is 415 mm, L3 is 204.5 mm, R2 is 31 mm, and the central angle ∠2 is 110°, ∠3 is 60°, ∠4 is 165°, φ6 is 165 mm, ∠5 is 24°, and ∠6 is 21°.

[0016] Furthermore, the collector includes a connecting portion, an air guide portion, an air inlet and an air guide port. The collector is fixedly connected to the volute through the connecting portion. The connecting portion is annular and the inner circumference forms the air inlet. The outlet of the air guide portion forms the air guide port.

[0017] The collector is cut with a plane passing through the central axis of the collector. In the cross section and in the direction from the air inlet to the air guide outlet, the air guide portion includes an air guide portion arc segment and an air guide portion straight segment that are connected and arranged. The air guide portion forms a tapered arc structure along the air guide portion arc segment to the air guide portion straight segment.

[0018] Furthermore, the diameter φ1 of the air inlet is 519mm-522mm, the radius R1 of the arc section of the air guide portion is 51mm-52mm, and the arc length is 77.6mm-78.8mm, the length L1 of the straight section of the air guide portion is 52.5mm-54mm, the angle ∠1 between the straight section of the air guide portion and the central axis of the collector is 2.8°-3.2°, the diameter φ2 of the air guide port is 411mm-413mm, and the vertical distance L2 between the air inlet and the air guide port is 101mm-103mm.

[0019] Furthermore, φ1 is 520.4 mm, R1 is 51.5 mm, the arc length is 78.2 mm, L1 is 53.3 mm, ∠1 is 3°, φ2 is 412 mm, and L2 is 102 mm.

[0020] Furthermore, the profile of the volute includes a first diffuser straight segment, a volute tongue segment, a first arc segment, a second arc segment, a third arc segment, a fourth arc segment, and a second diffuser straight segment that are tangentially connected in sequence; the first diffuser straight segment and the second diffuser straight segment enclose an air outlet, and the first arc segment, the second arc segment, the third arc segment, and the fourth arc segment are not cocentric;

[0021] A rectangular coordinate system is established with the center of the impeller as the coordinate origin. When the first diffuser straight line segment is located in the second quadrant, the coordinates of the center O3 of the first arc segment are (-25.8, -25.8), the radius R4 is 312mm-313.5mm and the arc length is 169.5mm-171mm. The coordinates of the center O4 of the second arc segment are (30.4, -30.4), the radius R5 is 368mm-370mm and the arc length is 581.5mm-58 4mm, the coordinates of the center O1 of the third arc segment are (35.8, 35.8), the radius R6 is 434mm-436.5mm and the arc length is 686.5mm-670mm, the coordinates of the center O2 of the fourth arc segment are (-42.3, 42.3), the radius R7 is 511mm-516mm and the arc length is 810mm-815mm, the second diffuser straight line segment is perpendicular to the air outlet, and the first diffuser straight line segment is inclined along the air outlet.

[0022] Furthermore, a rectangular coordinate system is established with the center of the impeller as the coordinate origin. When the first diffuser straight segment is located in the second quadrant, the coordinates of the center O3 of the first arc segment are (-25.8, -25.8), the radius R4 is 312.8 mm, and the arc length is 170.4 mm. The coordinates of the center O4 of the second arc segment are (30.4, -30.4), the radius R5 is 369 mm, and the arc length is 582.7 mm. The coordinates of the center O1 of the third arc segment are (35.8, 35.8), the radius R6 is 435.2 mm, and the arc length is 688.2 mm. The coordinates of the center O2 of the fourth arc segment are (-42.3, 42.3), the radius R7 is 513.3 mm, and the arc length is 812.3 mm.

[0023] The width L8 of the air outlet is 328mm-332mm, and the height L7 is 428mm-432.5mm;

[0024] The radius R3 of the volute tongue segment is 19.5mm-20.5mm and the arc length is 52mm-53.5mm. The length L4 of the first diffuser straight segment is 92.9mm-93.9mm. The length L6 of the second diffuser straight segment is 364mm-366.5mm. A tangent line is drawn to the volute tongue segment at the tangent point between the volute tongue segment and the first arc segment. The angle ∠9 between the tangent line and the first diffuser straight segment is 32°-32.7°.

[0025] The width L11 of the volute is 883mm-886mm, and the height L10 of the volute is 995mm-1000mm;

[0026] The volute is cut with a plane passing through the center of the impeller and perpendicular to the air outlet to form a cutting plane 1, and a vertical distance L9 between a cutting plane passing through the center line of the air outlet and parallel to the cutting plane 1 and the cutting plane 1 is 339 mm-340 mm.

[0027] Furthermore, it also includes an air inlet flange, a motor and a base, the air inlet flange is fixedly arranged on the volute, the motor is connected to the impeller through the motor shaft, and the volute and the motor are fixedly arranged on the base; the air inlet flange is annular and the inner diameter φ7 is 500mm;

[0028] L8 is 330mm, L7 is 430mm, R3 is 20mm and the arc length is 52.8mm, L4 is 93.4mm, L6 is 365.3mm, ∠9 is 32.31°, L11 is 884.6mm, L10 is 997mm, and L9 is 339.6mm.

[0029] The present invention provides a multi-blade centrifugal fan with high static pressure and low noise, (1) the profile of the volute adopts an unequal rectangular square spiral line, and the volute tongue adopts a short tongue design to control the static pressure loss, suppress the vortex at the air outlet of the volute and the air flow disturbance in the volute cavity, thereby improving the static pressure and efficiency of the fan and reducing the fan noise; (2) the inlet angle, outlet angle and blade shape of the impeller are improved, further improving the static pressure and efficiency of the fan; and the impeller support rod is designed to enhance the strength of the impeller, prevent the impeller from being deformed when the static pressure of the fan is increased, and improve the safety performance and service life of the fan; (3) the collector adopts a combination of an arc section of the air guide part and a straight section of the air guide part to achieve a variable diameter to form a tapered arc structure, which has a small air flow pressure loss, and the air flow can enter the impeller channel more smoothly. Moreover, the vortex area formed by the air flow after entering the impeller is smaller, thereby improving the air intake effect of the fan and further improving the static pressure and efficiency of the fan. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a structural schematic diagram of the present invention;

[0031] Figure 2 Schematic diagram of the volute profile;

[0032] Figure 3 is a schematic side cross-sectional view of the volute;

[0033] Figure 4 is a structural diagram of the impeller;

[0034] Figure 5 Schematic diagram of the side cross-sectional structure of the impeller;

[0035] Figure 6 is a side sectional view of the current collector;

[0036] Figure 7 is a performance curve diagram of the present invention;

[0037] Figure 8 It is a performance curve diagram of the comparison ratio.

[0038] Description of reference numerals:

[0039] Volute 1; first diffuser straight section 11; volute tongue section 12; first arc segment 13; second arc segment 14; third arc segment 15; fourth arc segment 16; second diffuser straight section 17; air outlet 18;

[0040] Impeller 2; blades 21; front disc 22; rear disc 23; air inlet 24; shaft disc 25; impeller support rod 26; first impeller support rod 261; second impeller support rod 262; third impeller support rod 263; fourth impeller support rod 264;

[0041] Current collector 3; connecting portion 31; air guide portion 32; air guide portion arc segment 321; air guide portion straight segment 322; air inlet 33; air guide port 34;

[0042] Air inlet flange 4; motor 5; base 6. DETAILED DESCRIPTION

[0043] The present invention is described in detail below with reference to specific embodiments.

[0044] 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.

[0045] The structural parameters adopted in the present invention are only for illustrating the technical solution of the present invention. That is, based on the basic structural parameters of the present invention, reasonable proportional scaling can be performed in actual production (for example, when the diameter of the outer circle surrounded by the outer ends of all the blades of the impeller is 500 mm, it can be scaled by 0.1-30 times, etc.), and such reasonable proportional scaling also falls within the scope of protection of the present invention.

[0046] See also Figure 1-8 , a multi-blade centrifugal fan with high static pressure and low noise, comprising a volute 1, an impeller 2 and a collector 3 arranged in the inner cavity of the volute 1, the collector 3 and the impeller 2 are coaxially arranged, the impeller 2 comprises a front disc 22 and a rear disc 23, the middle part of the front disc 22 is provided with an air suction port 24, and the rear disc 23 is surrounded by a plurality of blades 21 in an array; the profile of the volute 1 is an unequally spaced square spiral line, the volute tongue of the volute 1 is arranged to expand outward, and the angle ∠10 of the outward expansion of the volute tongue is 26.6°-27.4°; the diameter of the outer circle surrounded by the outer ends of all the blades 21 of the impeller 2 is φ3, the vertical spacing between the impeller 2 and the volute tongue is L5, and the ratio of L5 to φ3 is 0.147-0.15; an axial gap L13 is provided between the collector 3 and the impeller 2, and the ratio of L13 to φ3 is 0.02-0.025. Preferably, φ3 is 500 mm, ∠10 is 27°, L5 is 73.7 mm, and L13 is 10 mm.

[0047] Through the above technical solution, the profile of the volute 1 adopts an unequal-rectangular square spiral line, and the volute tongue adopts a short tongue design to control the static pressure loss, suppress the vortex at the air outlet 18 of the volute 1 and the air flow disturbance in the volute 1 cavity, thereby improving the fan static pressure and fan efficiency and reducing the fan noise.

[0048] In this embodiment, the inner diameter φ4 of the circle enclosed by the inner ends of all blades 21 of the impeller 2 is 400 mm to 402 mm, the diameter φ5 of the air inlet 24 is 414 mm to 416 mm, and the width L3 of the impeller 2 is 203.5 mm to 205.5 mm. The blades 21 are curved sheet metal blades, with a radius R2 of 30 mm to 32 mm and a central angle ∠2 of 109.2° to 110.8°. The inlet angle ∠3 of the blades 21 when installed is 59.3° to 60.7°, and the outlet angle ∠4 of the blades 21 when installed is 164° to 166°. The number of blades is 42. Preferably, φ4 is 401 mm, φ5 is 415 mm, L3 is 204.5 mm, R2 is 31 mm, and the central angles ∠2 and ∠3 are 110° and 60°, respectively.

[0049] Through the above technical solution, the inlet angle, outlet angle of the impeller 2 and the shape of the blades 21 are improved, and the static pressure and efficiency of the fan are further improved.

[0050] In this embodiment, the impeller 2 further includes a wheel disc 25 and four impeller support rods 26. The wheel disc 25 is arranged in the middle of the rear disc 23. One end of the impeller support rod 26 is fixedly connected to the wheel disc 25, and the other end of the impeller support rod 26 is fixedly connected to the front disc 22.

[0051] The impeller support rods 26 include a first impeller support rod 261, a second impeller support rod 262, a third impeller support rod 263, and a fourth impeller support rod 264. On the projection surface of the rear disc 23, the connection points of the four impeller support rods 26 and the impeller disc 25 are evenly distributed on a cocircle, and the diameter φ6 of the circle is 164 mm to 166 mm. The first impeller support rod 261 and the third impeller support rod 263 are parallel, and the second impeller support rod 262 and the fourth impeller support rod 264 are parallel.

[0052] The connection points of the first support rod 261 and the wheel disc 25 and the connection points of the third support rod 263 and the wheel disc 25 are connected to form a first connecting line passing through the center of the impeller 2. The connection points of the second support rod 262 and the wheel disc 25 and the connection points of the fourth support rod 264 and the wheel disc 25 are connected to form a second connecting line passing through the center of the impeller 2. The angle between the first support rod 261 and the second connecting line is ∠5, the angle between the third support rod 263 and the second connecting line is ∠7, the angle between the second support rod 262 and the first connecting line is ∠6, and the angle between the fourth support rod 264 and the first connecting line is ∠8. ∠5 and ∠7 are equal and are both 23.5°-24.5°, and ∠6 and ∠8 are equal and are both 20.5°-21.5°. Preferably, φ6 is 165 mm, ∠5 is 24°, and ∠6 is 21°.

[0053] Through the above technical solution, the design of the multi-blade centrifugal fan improves the static pressure of the fan, but the increase in static pressure will produce greater pressure on the impeller 2. Therefore, this application designs the impeller support rod 26 to enhance the strength of the impeller 2, prevent the impeller 2 from being deformed when the static pressure of the fan is increased, and improve the safety performance and service life of the fan.

[0054] In this embodiment, the collector 3 includes a connecting portion 31, an air guide portion 32, an air inlet 33, and an air guide port 34. The collector 3 is fixedly connected to the volute 1 via the connecting portion 31. The connecting portion 31 is annular and has an air inlet 33 formed on its inner periphery. The outlet of the air guide portion 32 forms the air guide port 34.

[0055] The collector 3 is cut with a plane passing through the central axis of the collector 3. In the cross section and in the direction from the air inlet 33 to the air guide outlet 34, the air guide portion 32 includes an air guide portion arc segment 321 and an air guide portion straight segment 322 that are connected to each other. The air guide portion 32 forms a tapered arc structure along the air guide portion arc segment 321 to the air guide portion straight segment 322.

[0056] In this embodiment, the diameter φ1 of the air inlet 33 is 519 mm to 522 mm, the radius R1 of the air guide arc segment 321 is 51 mm to 52 mm, and the arc length is 77.6 mm to 78.8 mm. The length L1 of the air guide straight segment 322 is 52.5 mm to 54 mm, and the angle ∠1 between the air guide straight segment 322 and the central axis of the current collector 3 is 2.8° to 3.2°. The diameter φ2 of the air guide 34 is 411 mm to 413 mm, and the vertical distance L2 between the air inlet 33 and the air guide 43 is 101 mm to 103 mm. Preferably, φ1 is 520.4 mm, R1 is 51.5 mm, the arc length is 78.2 mm, L1 is 53.3 mm, ∠1 is 3°, φ2 is 412 mm, and L2 is 102 mm.

[0057] Through the above technical solution, the collector 3 adopts the combination of the circular arc segment 321 of the air guide part and the straight segment 322 of the air guide part to achieve diameter change to form a tapered conical arc structure, the airflow pressure loss is small, the airflow can enter the channel of the impeller 2 more smoothly, and the vortex area formed by the airflow after entering the impeller 2 is smaller, which improves the air intake effect of the fan and further improves the static pressure and efficiency of the fan.

[0058] In this embodiment, the profile of the volute 1 includes a first diffuser straight segment 11, a volute tongue segment 12, a first arc segment 13, a second arc segment 14, a third arc segment 15, a fourth arc segment 16, and a second diffuser straight segment 17, which are tangentially connected in sequence. The first diffuser straight segment 11 and the second diffuser straight segment 17 enclose an air outlet 18, and the first arc segment 13, the second arc segment 14, the third arc segment 15, and the fourth arc segment 16 are not cocentric.

[0059] A rectangular coordinate system is established with the center of the impeller 2 as the coordinate origin. When the first diffuser straight segment 11 is located in the second quadrant, the coordinates of the center O3 of the first arc segment 13 are (-25.8, -25.8), the radius R4 is 312mm-313.5mm, and the arc length is 169.5mm-171mm. The coordinates of the center O4 of the second arc segment 14 are (30.4, -30.4), the radius R5 is 368mm-370mm, and the arc length is 581.5mm-584mm. The coordinates of the center O1 of the third arc segment 15 are (35.8, 35.8), the radius R6 is 434mm-436.5mm, and the arc length is 686.5mm-670mm. The coordinates of the center O2 of the fourth arc segment 16 are (-42.3, 42.3), the radius R7 is 511mm-516mm, and the arc length is 810mm-815mm. The second diffuser straight segment 17 is perpendicular to the air outlet 18, and the first diffuser straight segment 11 is inclined along the air outlet 18.

[0060] Preferably, a rectangular coordinate system is established with the center of the impeller 2 as the coordinate origin. When the first diffuser straight segment 11 is located in the second quadrant, the coordinates of the center O3 of the first arc segment 13 are (-25.8, -25.8), the radius R4 is 312.8 mm, and the arc length is 170.4 mm. The coordinates of the center O4 of the second arc segment 14 are (30.4, -30.4), the radius R5 is 369 mm, and the arc length is 582.7 mm. The coordinates of the center O1 of the third arc segment 15 are (35.8, 35.8), the radius R6 is 435.2 mm, and the arc length is 688.2 mm. The coordinates of the center O2 of the fourth arc segment 16 are (-42.3, 42.3), the radius R7 is 513.3 mm, and the arc length is 812.3 mm.

[0061] In this embodiment, the width L8 of the air outlet is 328mm-332mm, and the height L7 is 428mm-432.5mm; the radius R3 of the volute tongue segment is 19.5mm-20.5mm and the arc length is 52mm-53.5mm, the length L4 of the first diffuser straight segment is 92.9mm-93.9mm, and the length L6 of the second diffuser straight segment is 364mm-366.5mm. The tangent point of the volute tongue segment and the first arc segment is the tangent point. A tangent line is drawn through the volute tongue segment, and the angle ∠9 between the tangent line and the first diffuser straight line segment is 32°-32.7°. The volute width L11 is 883mm-886mm, and the volute height L10 is 995mm-1000mm. The volute is cut through a plane passing through the center of the impeller and perpendicular to the air outlet to form a cross-section plane 1. The vertical distance L9 between the cross-section plane 1 and the cross-section plane 1 passing through the centerline of the air outlet and parallel to the cross-section plane 1 is 339mm-340mm. Preferably, L8 is 330mm, L7 is 430mm, R3 is 20mm and the arc length is 52.8mm, L4 is 93.4mm, L6 is 365.3mm, ∠9 is 32.31°, L11 is 884.6mm, L10 is 997mm, and L9 is 339.6mm.

[0062] Through the above technical solution, the profile of the volute 1 adopts an unequal-rectangular square spiral line, and the volute tongue adopts a short tongue design to control the static pressure loss, suppress the vortex at the air outlet 18 of the volute 1 and the air flow disturbance in the volute 1 cavity, thereby improving the fan static pressure and fan efficiency and reducing the fan noise.

[0063] In this embodiment, it also includes an air inlet flange 4, a motor 5 and a machine base 6. The air inlet flange 4 is fixedly arranged on the volute 1, the motor 5 is connected to the impeller 2 through the motor shaft, and the volute 1 and the motor 5 are both fixedly arranged on the machine base 6; the air inlet flange 4 is annular and the inner diameter φ7 is 500 mm.

[0064] Through the above technical solution, the diameter of the air inlet flange 4 is the same as the diameter of the impeller 2, which is conducive to the stability of the air intake volume and the stable flow of the airflow in the fan, and can further ensure the efficiency of the fan and reduce the fan noise.

[0065] In order to verify this embodiment, based on the preferred structural parameters provided in this embodiment, a high static pressure and low noise multi-blade centrifugal fan was manufactured with an impeller 2 diameter of 500 mm (i.e., the diameter of the outer circumference surrounded by the outer ends of all blades 21 of the impeller 2) as a test example for testing. At the same time, a traditional multi-blade centrifugal fan with an impeller 2 diameter of 500 mm was tested as a comparative example. The test results were converted to atmospheric pressure of 101325 Pa, atmospheric temperature of 20 ° C, fan speed of 960 r / min, and medium density of 1.2 kg / m 3The test data under the test conditions, the test case obtained the test data shown in Table 1 and Figure 7 The performance curve shown in Table 2 is obtained as a comparative example. Figure 8 The performance curve shown is based on volume flow as the horizontal axis. In the performance curve, qvsglGu is the volume flow, LAGu is the A sound level, ηr is the fan efficiency, PrGu is the impeller power, pFGu is the total pressure, and psFGu is the static pressure.

[0066] Table 1

[0067]

[0068] Table 2

[0069]

[0070] From the test data and performance curves, it can be seen that the control ratio is worse than the test example in terms of total pressure, static pressure, fan efficiency and A sound level. In contrast, the optimal fan efficiency of the test example is 68.543% at the working point, and the volume flow rate is 9267.6m 3 / h, total pressure is 1044.4Pa, static pressure is 850.25Pa, and sound level A is 76.011dB; when the optimal fan efficiency of the test case is 60.343% operating point, the volume flow rate is 6586.46m 3 / h, total pressure of 865.46Pa, static pressure of 705.75Pa, and sound level A of 78.801dB. The test cases generally had higher fan efficiency and higher static pressure than the control cases, and the sound level A of the test cases generally decreased compared to the control cases.

[0071] At the same time, in the test case, when the impeller power is 5.1992kW, the volume flow rate is 11739m 3 / h, the total pressure is 1049.1Pa, the static pressure is still 737.02Pa, the fan efficiency is 65.605%, the A sound level is 77.836dB, and the ratio of static pressure to total pressure is still 70.25%; in the comparative example, when the impeller power is 3.7430kW operating point, the volume flow rate is 9247.7m 3 / h, the total pressure is 745.36Pa, the static pressure is 429.47Pa, the fan efficiency is 51.071%, and the sound level A is 81.290dB. At this time, both the total pressure and the static pressure drop sharply, and the ratio of static pressure to total pressure drops sharply to 57.62%.

[0072] The above comparison results show that the test example has a smoother total pressure curve, smaller static pressure fluctuations, and a lower A-sound level. At similar impeller power, the test example has higher fan efficiency, static pressure, and static pressure-to-total pressure ratio than the comparison example. At similar volumetric flow rates, the test example's A-sound level is lower than that of the comparison example, resulting in lower noise levels.

[0073] Compared with the prior art, the multi-blade centrifugal fan with high static pressure and low noise of the present invention has the effects of high efficiency, high static pressure and low noise.

[0074] In the absence of conflict, the above embodiments and features therein may be combined with each other.

[0075] 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. A multi-blade centrifugal fan with high static pressure and low noise, comprising a volute, an impeller disposed within the volute's inner cavity, and a flow collector, the flow collector being coaxially disposed with the impeller, the impeller comprising a front disc and a rear disc, the front disc having an air intake disposed in the middle thereof, and a plurality of blades arrayed around the rear disc, characterized in that: The profile of the volute is an unequally spaced square spiral line, and the volute tongue of the volute is set to an outward expansion structure, and the outward expansion angle ∠10 of the volute tongue is 26.6°-27.4°; The diameter of the outer circle formed by the outer ends of all blades of the impeller is φ3, the vertical distance between the impeller and the volute tongue is L5, and the ratio of L5 to φ3 is 0.147-0.15; An axial gap L13 is set between the collector and the impeller, and the ratio of L13 to φ3 is 0.02-0.025; The impeller also includes a wheel disc and four impeller support rods. The wheel disc is arranged in the middle of the rear disc. One end of the impeller support rod is fixedly connected to the wheel disc, and the other end of the impeller support rod is fixedly connected to the front disc. The impeller support rods include a first impeller support rod, a second impeller support rod, a third impeller support rod, and a fourth impeller support rod. On the projection surface of the rear disc, the connection points of the four impeller support rods and the disc are evenly distributed on a cocircle, and the diameter φ6 of the circle is 164mm-166mm. The first impeller support rod and the third impeller support rod are parallel, and the second impeller support rod and the fourth impeller support rod are parallel. Connect the connection point between the first support rod and the wheel disc and the connection point between the third support rod and the wheel disc to form a first connection line passing through the center of the impeller, connect the connection point between the second support rod and the wheel disc and the connection point between the fourth support rod and the wheel disc to form a second connection line passing through the center of the impeller, the angle between the first support rod and the second connection line is ∠5, the angle between the third support rod and the second connection line is ∠7, the angle between the second support rod and the first connection line is ∠6, and the angle between the fourth support rod and the first connection line is ∠8, ∠5 and ∠7 are equal and are both 23.5°-24.5°, and ∠6 and ∠8 are equal and are both 20.5°-21.5°; The collector includes a connecting portion, an air guide portion, an air inlet and an air guide port. The collector is fixedly connected to the volute through the connecting portion. The connecting portion is annular and the inner circumference forms the air inlet. The outlet of the air guide portion forms the air guide port. The collector is cut with a plane passing through the central axis of the collector. In the cross section and in the direction from the air inlet to the air guide outlet, the air guide portion includes an air guide portion arc segment and an air guide portion straight segment that are connected and arranged. The air guide portion forms a tapered arc structure along the air guide portion arc segment to the air guide portion straight segment.

2. The multi-blade centrifugal fan with high static pressure and low noise according to claim 1, characterized in that: φ3 is 500mm, ∠10 is 27°, L5 is 73.7mm, and L13 is 10mm; The inner diameter φ4 of the circle formed by the inner ends of all the blades of the impeller is 400mm-402mm, the diameter φ5 of the air suction port is 414mm-416mm, and the width L3 of the impeller is 203.5mm-205.5mm; The blade is an arc-shaped sheet metal blade, the radius R2 of the blade is 30mm-32mm and the central angle ∠2 is 109.2°-110.8°, the inlet angle ∠3 when the blade is installed is 59.3°-60.7°, and the outlet angle ∠4 when the blade is installed is 164°-166°; The number of blades is 42.

3. The multi-blade centrifugal fan with high static pressure and low noise according to claim 2, characterized in that: φ4 is 401mm, φ5 is 415mm, L3 is 204.5mm, R2 is 31mm and the central angle ∠2 is 110°, ∠3 is 60°, ∠4 is 165°, φ6 is 165mm, ∠5 is 24°, and ∠6 is 21°.

4. The multi-blade centrifugal fan with high static pressure and low noise according to claim 3, characterized in that: The diameter φ1 of the air inlet is 519mm-522mm, the radius R1 of the arc section of the air guide part is 51mm-52mm, and the arc length is 77.6mm-78.8mm, the length L1 of the straight section of the air guide part is 52.5mm-54mm, and the angle ∠1 between the straight section of the air guide part and the central axis of the collector is 2.8°-3.2°. The diameter φ2 of the air guide port is 411mm-413mm, and the vertical distance L2 between the air inlet and the air guide port is 101mm-103mm.

5. The multi-blade centrifugal fan with high static pressure and low noise according to claim 4, characterized in that: φ1 is 520.4 mm, R1 is 51.5 mm, the arc length is 78.2 mm, L1 is 53.3 mm, ∠1 is 3°, φ2 is 412 mm, and L2 is 102 mm.

6. The multi-blade centrifugal fan with high static pressure and low noise according to claim 5, characterized in that: The profile of the volute includes a first diffuser straight segment, a volute tongue segment, a first arc segment, a second arc segment, a third arc segment, a fourth arc segment, and a second diffuser straight segment, which are sequentially connected tangentially; the first diffuser straight segment and the second diffuser straight segment enclose an air outlet, and the first arc segment, the second arc segment, the third arc segment, and the fourth arc segment are not cocentric; A rectangular coordinate system is established with the center of the impeller as the coordinate origin. When the first diffuser straight line segment is located in the second quadrant, the coordinates of the center O3 of the first arc segment are (-25.8, -25.8), the radius R4 is 312mm-313.5mm and the arc length is 169.5mm-171mm. The coordinates of the center O4 of the second arc segment are (30.4, -30.4), the radius R5 is 368mm-370mm and the arc length is 581.5mm-58 4mm, the coordinates of the center O1 of the third arc segment are (35.8, 35.8), the radius R6 is 434mm-436.5mm and the arc length is 686.5mm-670mm, the coordinates of the center O2 of the fourth arc segment are (-42.3, 42.3), the radius R7 is 511mm-516mm and the arc length is 810mm-815mm, the second diffuser straight line segment is perpendicular to the air outlet, and the first diffuser straight line segment is inclined along the air outlet.

7. The multi-blade centrifugal fan with high static pressure and low noise according to claim 6, characterized in that: A rectangular coordinate system is established with the center of the impeller as the coordinate origin. When the first diffuser straight segment is located in the second quadrant, the coordinates of the center O3 of the first arc segment are (-25.8, -25.8), the radius R4 is 312.8 mm, and the arc length is 170.4 mm. The coordinates of the center O4 of the second arc segment are (30.4, -30.4), the radius R5 is 369 mm, and the arc length is 582.7 mm. The coordinates of the center O1 of the third arc segment are (35.8, 35.8), the radius R6 is 435.2 mm, and the arc length is 688.2 mm. The coordinates of the center O2 of the fourth arc segment are (-42.3, 42.3), the radius R7 is 513.3 mm, and the arc length is 812.3 mm. The width L8 of the air outlet is 328mm-332mm, and the height L7 is 428mm-432.5mm; The radius R3 of the volute tongue segment is 19.5mm-20.5mm and the arc length is 52mm-53.5mm. The length L4 of the first diffuser straight segment is 92.9mm-93.9mm. The length L6 of the second diffuser straight segment is 364mm-366.5mm. A tangent line is drawn to the volute tongue segment at the tangent point between the volute tongue segment and the first arc segment. The angle ∠9 between the tangent line and the first diffuser straight segment is 32°-32.7°. The width L11 of the volute is 883mm-886mm, and the height L10 of the volute is 995mm-1000mm; The volute is cut with a plane passing through the center of the impeller and perpendicular to the air outlet to form a cutting plane 1, and a vertical distance L9 between a cutting plane passing through the center line of the air outlet and parallel to the cutting plane 1 and the cutting plane 1 is 339 mm-340 mm.

8. The multi-blade centrifugal fan with high static pressure and low noise according to claim 7, characterized in that: The air inlet flange is fixed on the volute, the motor is connected to the impeller through the motor shaft, and the volute and the motor are fixed on the volute; the air inlet flange is annular and the inner diameter is φ7, which is 500 mm; L8 is 330mm, L7 is 430mm, R3 is 20mm and the arc length is 52.8mm, L4 is 93.4mm, L6 is 365.3mm, ∠9 is 32.31°, L11 is 884.6mm, L10 is 997mm, and L9 is 339.6mm.

Images