Impeller structure with baffles at outlet parts of folded blades and vortex pump

Abstract

The invention provides an impeller structure with baffles at outlet parts of folded blades and a vortex pump. The impeller structure comprises a rear cover plate, a plurality of folded blades on the front end face of the rear cover plate, a plurality of back blades on the rear end face of the rear cover plate, the baffles on the folded blades and a hub in the center of the rear cover plate. The folded blade comprises a long blade section and a short blade section which are connected with each other, the baffle plate is vertically arranged on a pressure surface and / or a suction surface of the short blade section, the width of the baffle plate is b0 = (1-2) t, the thickness of the baffle plate is t0 = (0.5-0.8) t, b0 is the width of the baffle plate, t0 is the thickness of the baffle plate, and t is the thickness of the folded blade. The baffle is arranged at the outlet part of the folded blade, so that fluid can be better guided to flow to the outlet, abrasion and blockage caused by the fact that a medium in a vaneless cavity flows into a blade channel are reduced, flow state disturbance and hydraulic loss of the blade channel are reduced, and the conveying efficiency of the vortex pump is improved.

Description

Technical Field

[0001] The invention relates to the technical field of open vortex pumps, in particular to an impeller structure with a baffle provided at an outlet of a folded blade and a vortex pump. Background Art

[0002] A swirl pump is a special type of centrifugal pump, and its working principle is to transport the medium based on swirl technology. It generates a rotating fluid movement inside the pump body. This movement makes the pressure in the middle of the vortex low, and can continuously suck the medium, and form a high-energy circulation on the periphery, and finally discharge it from the pump cavity. This type of pump is usually used in the transportation of solid media, especially in situations where the solid particles are large, the solid fibers are long, or the solid volume concentration is large. The emergence of swirl pumps is to solve the shortcomings of traditional centrifugal pumps in handling certain fluid media, such as handling situations containing solid particles or high-viscosity liquids. Traditional centrifugal pumps may experience blockage or inefficiency when handling such fluids, while swirl pumps can transport these fluids more efficiently through swirl technology. The impeller design and pump body structure of the swirl pump enable it to generate a high-speed rotating liquid flow, so that it can more effectively transport the solid medium.

[0003] However, although the vortex pump impeller has a simple structure, is easy to manufacture and has good non-clogging performance, when the impeller rotates, the energy of the medium increases under the action of centrifugal force, and it is easy to form a circulating flow in the bladeless cavity on one side of the impeller and then flow into the blade channel, causing wear and blockage, low energy conversion, large hydraulic loss, and low efficiency. Most efficiencies are below 60%, resulting in energy waste. Summary of the invention

[0004] In response to the problem of low transport efficiency of solid media by vortex pumps, the present invention provides an impeller structure and a vortex pump with a baffle provided at the outlet part of the folded blade. By providing the baffle at the outlet part of the folded blade, the fluid can be better guided to flow to the outlet, and the wear and blockage caused by the medium in the bladeless cavity flowing into the blade channel can be reduced, thereby reducing the disturbance of the flow state in the blade channel and the hydraulic loss, and improving the transport efficiency of the vortex pump.

[0005] The present invention achieves the above technical objectives through the following technical means.

[0006] An impeller structure with a baffle plate at the outlet of a folding blade, the impeller adopts a semi-open impeller structure, the impeller comprises a rear cover plate, a plurality of folding blades on the front end surface of the rear cover plate, a plurality of back blades on the rear end surface of the rear cover plate, a baffle plate on the folding blade, and a hub at the center of the rear cover plate; the folding blade comprises a connected long blade segment and a short blade segment, the long blade segment rotates around an end point A of the inlet end close to the impeller hub, and forms an angle of θ with a diameter on the rear cover plate passing through the end point A 1The short blade segment rotates around its connection point with the long blade segment and forms an angle of θ with the extension line of the long blade segment 2 The baffle is vertically mounted on the pressure surface and / or suction surface of the short blade segment, the side of the baffle away from the rear cover is flush with the side of the short blade segment away from the rear cover, and the two ends of the baffle are respectively connected with the outlet end point B of the short blade segment and the connection point between the short blade segment and the long blade segment; the width and thickness of the baffle are:

[0007] b 0 =(1~2)t (1)

[0008] t 0 =(0.5~0.8)t (2)

[0009] Among them, b 0 is the baffle width, t 0 is the baffle thickness, and t is the folding blade thickness.

[0010] Furthermore, the end of the baffle plate close to the long blade section is rounded, and the rounded radius r = (0.8-1.2) b 0 .

[0011] Furthermore, the thickness t of the folding blade is 4 to 12 mm, and the inlet diameter D of the folding blade is 1 , the outlet diameter of the folding blade D 2 and the outlet width b of the folding blade 1 for:

[0012]

[0013] b 1 =(0.15~0.21)D 1 (5)

[0014] Among them, the coefficient K 1 =2~2.4, Q is the flow rate of the pump, in m 3 / s, n is the impeller speed, unit is r / min, μ is the flow slip degree between the folded blades, η h is the hydraulic efficiency of the pump without baffles at the folding blade outlet, and H is the pump head without baffles at the folding blade outlet, in m.

[0015] Furthermore, the first angle θ 1 Take 15°~60°, the second angle θ 2 Take 30°~60°.

[0016] Furthermore, the number of the folding blades is 8 to 12, and they are evenly distributed around the circumference on the front end surface of the rear cover plate.

[0017] Furthermore, the number and thickness of the back blades are consistent with those of the folding blades.

[0018] Furthermore, the ratio of the length of the short leaf segment to the long leaf segment is 1:2.

[0019] Furthermore, the baffle is fixed on the folding blade by welding, or is integrally formed with the folding blade.

[0020] A vortex pump comprising an impeller structure as described in any one of the above items.

[0021] Furthermore, a gap of 0.5 to 2 mm is left between the back blade and the pump housing.

[0022] The beneficial effects of the present invention are as follows:

[0023] 1. The impeller structure of the present invention can more effectively improve the fluid passing rate when transporting solid-liquid two-phase flow, and adding a baffle at the blade outlet can effectively reduce the fluid flowing into the bladeless cavity on one side of the impeller and form a circulating flow, thereby reducing the medium in the bladeless cavity from flowing into the blade channel to cause wear and blockage, reducing the disturbance of the blade channel flow state and hydraulic loss, and improving the delivery efficiency of the vortex pump.

[0024] 2. The baffle in the present invention is installed on the pressure surface and / or suction surface of the short blade segment, preferably on the suction surface of the short blade segment, which can minimize the flow of fluid into the bladeless cavity on one side of the impeller and form a circulating flow, and can also avoid excessive load on the impeller due to the increase in the weight of the baffle, thereby affecting the lift and efficiency of the impeller. At the same time, the width and thickness of the baffle are controlled according to the width of the folded blade. Finally, the lift of the impeller can be increased to more than 6.2m and the efficiency can be increased to more than 60% under the triple improvement of the installation position, width and thickness.

[0025] 3. The baffle in the present invention has a rounded structure at one end close to the long blade section, which can not only effectively reduce the contact area between the solid medium, especially the flocs and the baffle, and avoid the entanglement of materials during transportation, thereby significantly reducing the risk of blockage caused by entanglement and improving the anti-entanglement performance, but also can improve the transportation efficiency to a certain extent and ensure the smooth passage of materials.

[0026] 4. The baffle in the present invention has the advantages of simple structure and easy processing. It can not only significantly improve the pump head efficiency during operation, but also protect the blades when conveying media containing solid particles, thereby increasing the service life of the impeller.

[0027] 5. Compared with the impeller of the conventional non-clogging pump, the impeller of the present invention is not completely retracted to the rear chamber, but only at the rear side of the pump chamber. The impeller has a simple structure and is easy to manufacture. Most of the solids are directly sent to the volute chamber without passing through the impeller. It has good passability and anti-fiber winding performance, high efficiency, and stable and reliable operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a front stereoscopic view of an impeller structure with a baffle at the outlet portion of the folding blades described in the present invention.

[0029] Figure 2 This is a front view of an impeller structure with a baffle at the outlet portion of the folding blades according to the present invention.

[0030] Figure 3 This is a partial enlarged view of the baffle.

[0031] Figure 4 This is a three-dimensional back view of the impeller structure with a baffle at the outlet portion of the folding blades according to the present invention.

[0032] The reference numerals are as follows:

[0033] 1-rear cover; 2-folding blade; 21-long blade section; 22-short blade section; 3-back blade; 4-baffle; 5-hub. DETAILED DESCRIPTION

[0034] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments, but the protection scope of the present invention is not limited thereto.

[0035] Example 1

[0036] The impeller structure with a baffle at the outlet of the folding blades in this embodiment adopts a semi-open impeller structure, and the impeller includes a rear cover plate 1, 10 folding blades 2 evenly distributed around the circumference on the front end surface of the rear cover plate 1, 10 back blades 3 evenly distributed around the circumference on the rear end surface of the rear cover plate 1, a baffle 4 on the folding blades 2, and a hub 5 at the center of the rear cover plate 1. The thickness t of the folding blades 2 is 0.004m. Figure 1 This is a front stereoscopic view of the impeller structure with a baffle provided at the outlet portion of the folding blades described in this embodiment.

[0037] The folding blade 2 includes a long blade segment 21 and a short blade segment 22 connected to each other. The long blade segment 21 rotates around its inlet end point A close to the impeller hub 5 and forms a first angle of 30° with the diameter of the rear cover plate 1 passing through the end point A. The short blade segment 22 rotates around its connection point with the long blade segment 21 and forms a second angle of 30° with the extension line of the long blade segment 21. The baffle 4 is welded and fixed vertically on the suction surface of the short blade segment 22. The side of the baffle 4 away from the rear cover plate 1 is flush with the side of the short blade segment 22 away from the rear cover plate 1, and the two ends of the baffle 4 are respectively connected with the outlet end point B of the short blade segment 22 and the connection point between the short blade segment 22 and the long blade segment 21. Figure 3 It is a partial enlarged view of the baffle. The width and thickness of the baffle 4 are:

[0038] b 0 =(1~2)t (1)

[0039] t 0 =(0.5~0.8)t (2)

[0040] Among them, b 0 is the baffle width, in m, t 0 is the baffle thickness, in m, t is the folding blade thickness, in m, where t 0 Take 0.002m.

[0041] The end of the baffle 4 close to the long blade section 21 is rounded; the radius of the rounding r = (0.8-1.2) b 0 , here we take r = b 0 .

[0042] The ratio of the length of the short blade section 22 to the length of the long blade section 21 is 1:2. The inlet diameter D of the folding blade 2 1 , the outlet diameter D of the folding blade 2 2 and the outlet width b of the folding blade 2 1 for:

[0043]

[0044] b 1 =(0.15~0.21)D 1 (5)

[0045] Among them, the coefficient K 1 =2~2.4, Q is the flow rate of the pump, in m 3 / s, n is the impeller speed, unit is r / min, μ is the flow slip degree between the folded blades, η h is the hydraulic efficiency of the pump without baffles at the outlet of the folding blades, H is the pump head without baffles at the outlet of the folding blades, in meters. In this embodiment, the total length of the folding blades is 0.0414m, D1 0.048m, D 2 is 0.128m, b 1 0.022m, Figure 2 This is a front view of an impeller structure with a baffle at the outlet portion of the folding blades according to the present invention.

[0046] In order to explore the different baffle 4 width b 0 In order to study the influence of impeller head efficiency, the performance of swirl pumps with 4 impellers equipped with baffles of different widths was calculated respectively, and the flow field was simulated by numerical calculation software CFX. The external characteristic results are shown in Table 1 below.

[0047] Table 1 The effect of baffles of different widths on the impeller head and efficiency

[0048] Lift(m) efficiency(%) Baffle width 0.003m 6.111 57.9 Baffle width 0.004m 6.238 60.1 Baffle width 0.006m 6.105 58.0 Baffle width 0.008m 6.076 55.3

[0049] From the numerical simulation, we know that when b 0 =1.5t, the degree of improvement of the impeller head efficiency by the baffle 4 is close to the maximum. The baffle 4 mainly plays the role of constraining the fluid, reducing the non-blade cavity fluid from the back of the blade entering the impeller flow channel, improving the flow state inside the impeller and reducing the flow loss. However, if the width of the baffle 4 is too small, it cannot play a good role in constraining the fluid, and the blade cavity fluid enters the impeller flow channel more from the back of the blade, and the flow state is turbulent. However, if the width of the baffle 4 is too large, it will also increase the load of the impeller, which will reduce the impeller head and efficiency, and is not conducive to conveying fluids containing particles and fibers.

[0050] Figure 4 This is a back stereoscopic view of the impeller structure with a baffle at the folding blade outlet portion described in this embodiment. The 10 back blades 3 on the rear end surface of the rear cover plate 1 correspond one-to-one to the folding blades 2, and the thickness of the back blades 3 is equal to the thickness of the folding blades 2.

[0051] The present embodiment also relates to a vortex pump including the above-mentioned impeller structure, wherein a gap of 0.5 to 2 mm is left between the back blade 3 and the pump casing, and the impeller is not installed and retracted into the rear pump chamber, so the anti-winding performance is better and the fluid flow state can be further improved.

[0052] The impeller of the present invention has a simple structure and is easy to manufacture. It can transport medium containing particles (such as granular metal, grains, silt, wood blocks, etc.) and fibers (wood pulp glass fiber, paper pulp, hemp rope, etc.). Most of the solids are directly sent to the volute without passing through the impeller, and the passability and anti-fiber winding performance are good. Adding a baffle 4 on the back of the blade outlet part can effectively prevent the circulation flow between the blades and prevent the loss caused by the secondary flow flowing from the front of the blade to the back of the blade, thereby better improving the flow state, increasing the head and efficiency of the pump, and running smoothly and reliably.

[0053] Example 2

[0054] The difference between this embodiment and embodiment 1 is that: the number of baffles 4 is 2 and they are respectively installed vertically on the suction surface and pressure surface of the short blade segment 22, the side of the baffle 4 away from the rear cover plate 1 is flush with the side of the short blade segment 22 away from the rear cover plate 1, and the two ends of the baffle 4 are respectively connected with the outlet end point B of the short blade segment 22 and the connection point between the short blade segment 22 and the long blade segment 21, and the cross-section of the two baffles 4 and the short blade segment 22 is "T" shaped. In addition, the specifications, shapes and other impeller structures of the baffle 4 are completely consistent with those of embodiment 1. In order to explore the influence of the presence or absence of baffles 4 and the installation position of baffles 4 on the impeller head efficiency, the performance of the impeller swirl pump with or without baffles 4 and with baffles 4 installed at different positions is calculated, and the flow field simulation is performed by numerical calculation software CFX. The external characteristic results are shown in Table 2 below.

[0055] Table 2 The effect of the presence or absence of baffle 4 and the baffle 4 in different installation positions on the impeller head and efficiency

[0056] Lift(m) efficiency(%) No baffle 4 5.933 56.8 Example 2 6.105 58.1 Example 1 6.238 60.1

[0057] From the numerical simulation, it can be seen that the impeller design with the baffle 4 at the blade outlet meets expectations, and the lift is improved compared to the impeller without the baffle 4. However, the T-shaped baffle causes excessive load on the impeller due to the increased weight, which in turn affects the lift and efficiency of the impeller. The use of the single baffle 4 in Example 1 can not only maximize the lift and efficiency of the impeller, but also ensure that the load of the impeller itself does not affect its lift and efficiency.

[0058] The embodiments are preferred implementations of the present invention, but the present invention is not limited to the above-mentioned implementations. Any obvious improvements, substitutions or modifications that can be made by those skilled in the art without departing from the essential content of the present invention belong to the protection scope of the present invention.

Claims

1. An impeller structure with a baffle at the outlet of the folding blade, characterized in that: The impeller adopts a semi-open impeller structure, comprising a rear cover plate (1), a plurality of folded blades (2) on the front end surface of the rear cover plate (1), a plurality of back blades (3) on the rear end surface of the rear cover plate (1), a baffle (4) on the folded blades (2), and a hub (5) at the center of the rear cover plate (1); the folded blades (2) comprise connected long blade sections (21) and short blade sections (22); the long blade sections (21) rotate around an end point A close to an inlet end of the impeller hub (5) and form a first clamping angle of θ1 with a diameter of the rear cover plate (1) passing through the end point A. The short blade segment (22) rotates around the connection point between the short blade segment (22) and the long blade segment (21), and forms a second angle of angle θ2 with the extension line of the long blade segment (21); the baffle (4) is vertically mounted on the pressure surface and / or suction surface of the short blade segment (22); a side of the baffle (4) away from the rear cover (1) is flush with a side of the short blade segment (22) away from the rear cover (1), and two ends of the baffle (4) are respectively connected to the outlet end point B of the short blade segment (22) and the connection point between the short blade segment (22) and the long blade segment (21); the width and thickness of the baffle (4) are: b0=(1~2)t (1) t0=(0.5~0.8)t (2) Among them, b0 is the baffle width, the unit is m, t0 is the baffle thickness, the unit is m, and t is the folding blade thickness, the unit is m.

2. The swirl pump impeller structure with a baffle at the outlet of the folded blade according to claim 1, characterized in that: One end of the baffle (4) close to the long blade section (21) is in a rounded structure, and the rounded radius r=(0.8-1.2)b0.

3. The impeller structure with a baffle at the outlet of the folding blade according to claim 1, characterized in that: The thickness t of the folding blade (2) is 4 to 12 mm, the inlet diameter D1 of the folding blade (2), the outlet diameter D2 of the folding blade (2) and the outlet width b1 of the folding blade (2) are: b1=(0.15~0.21)D1 (5) Among them, the coefficient K1 = 2 ~ 2.4, Q is the flow rate of the pump, the unit is m 3 / s, n is the impeller speed, unit is r / min, μ is the flow slip degree between the folded blades, η h is the hydraulic efficiency of the pump without baffles at the folding blade outlet, and H is the pump head without baffles at the folding blade outlet, in m.

4. The impeller structure with a baffle at the outlet of the folding blade according to claim 1, characterized in that: The first angle θ1 is between 15° and 60°, and the second angle θ2 is between 30° and 60°.

5. The impeller structure with a baffle at the outlet of the folding blade according to claim 1, characterized in that: The number of the folding blades (2) is 8 to 12, and they are evenly distributed around the circumference on the front end surface of the rear cover plate (1).

6. The impeller structure with a baffle at the outlet of the folding blade according to claim 1, characterized in that: The number and thickness of the back blades (3) are consistent with those of the folding blades (2).

7. The impeller structure with a baffle at the outlet of the folding blade according to claim 1, characterized in that: The ratio of the length of the short blade segment (22) to the length of the long blade segment (21) is 1:

2.

8. The impeller structure with a baffle at the outlet of the folding blade according to claim 1, characterized in that: The baffle (4) is welded and fixed on the folding blade (2), or is integrally formed with the folding blade (2).

9. A cyclone pump comprising the impeller structure according to any one of claims 1 to 8.

10. The vortex pump according to claim 9, characterized in that: A gap of 0.5 to 2 mm is left between the back blade (3) and the pump casing.

Images