Long and short blade back blade structure

Abstract

The utility model relates to the technical field of fluid machinery, in particular to a long and short blade back blade structure which comprises an impeller body, the impeller body comprises a hub, an impeller rear cover plate is fixed on the periphery of the hub, impeller blades are arranged on one side of the impeller rear cover plate, and an impeller front cover plate is arranged on the outer sides of the impeller blades. Long back blades and short back blades are fixed on the other side face of the impeller rear cover plate, and the long back blades and the short back blades are alternately arranged on the side face of the impeller rear cover plate in an axis circumferential distribution mode. When fluid flows into the back blade through the cavity, the main blade and the back blade coaxially rotate, on one hand, the axial force on the rear cover plate of the impeller can be reduced, and on the other hand, compared with a straight blade of the back blade, the reduction amplitude of the pump efficiency is small, and the increase of the shaft power is small, so that the axial force can be greatly reduced, and meanwhile, the influence on the external characteristics of the centrifugal pump is small.

Description

Technical Field

[0001] The utility model relates to the technical field of fluid machinery, in particular to a long and short blade back blade structure. Background Art

[0002] A pump is a prime mover used to increase the potential energy, pressure energy and kinetic energy of a liquid. It is divided into centrifugal pumps, mixed flow pumps and axial flow pumps according to the size of the specific speed.

[0003] A centrifugal pump is a pump that uses the centrifugal force generated by the rotation of the impeller to transport liquid. Its working principle is that before the water pump is started, the pump housing and the water suction pipe must be filled with water, and then the motor is started so that the pump shaft drives the impeller and water to rotate at high speed. At this time, the water is thrown to the outer edge of the impeller under the action of centrifugal force, and flows into the water pressure pipeline of the water pump through the flow channel of the volute pump housing, thereby realizing the transportation of liquid.

[0004] The basic structure of a centrifugal pump includes impeller, pump body, pump shaft, bearing, sealing ring and stuffing box. The impeller is the core part of the centrifugal pump. It has high speed and high output. The design of the blades allows water to move centrifugally smoothly. The pump body plays a supporting and fixing role and is connected to the bearing bracket. The pump shaft is connected to the motor through a coupling to drive the impeller to rotate.

[0005] During the operation of a centrifugal pump, due to the rotation of the impeller, axial force will inevitably be generated. As the requirements for stable operation of the centrifugal pump gradually increase, the axial force balance problem becomes more and more important. Especially for long-short blade impellers, since the main blade structure is a long blade plus a short blade structure, the axial force has a greater impact. Generally, clean water pumps use a seal plus a balancing hole structure to balance the axial force, but for the transportation of fluids containing impurities, it is more common to use a back blade structure to balance the axial force. While balancing the axial force, the back blade is also very effective in preventing impurities from entering the shaft seal.

[0006] Centrifugal pumps have the advantages of high head, small flow rate, and reliable use. They are widely used in chemical, petroleum, papermaking, water supply and drainage, road drainage, farmland irrigation, boiler water supply, laboratories and medical equipment. Whether it is transporting chemical liquids such as acid and alkali liquids, crude oil, and pulp, or used in urban water supply and drainage, road drainage, and farmland irrigation, centrifugal pumps can play an important role.

[0007] However, the current back blade design requires a small axial gap between it and the wall of the non-rotating component to ensure the normal rotation of the impeller. However, the existence of this gap also has a certain impact on the balance of the axial force. Utility Model Content

[0008] The utility model provides a long-short blade back blade structure, which solves the problem of large axial force in the back blade structure in the prior art.

[0009] A further purpose of the utility model is to distribute the fluid more evenly around the impeller, reduce the vibration and noise of the system, ensure the sealing of the pump body, reduce the energy consumption caused by friction, and play a role in cooling and lubrication.

[0010] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0011] A long-short blade back blade structure comprises an impeller body, the impeller body comprises a hub, an impeller rear cover plate is fixed to the outer periphery of the hub, one side of the impeller rear cover plate is provided with an impeller main blade, the outer side of the impeller blade is an impeller front cover plate, and the other side of the impeller rear cover plate is fixed with a back blade long blade and a back blade short blade, and the back blade long blade and the back blade short blade are alternately arranged on the side of the impeller rear cover plate and distributed on the circumference of the axis.

[0012] Preferably, the long back blade and the short back blade are both curved cylindrical blade structures, and are integrally formed with the impeller rear cover.

[0013] Preferably, the impeller is circular, and the long back blades and the short back blades are equidistantly distributed in a spiral circle with the center of the impeller as the center.

[0014] Preferably, the main blades of the impeller are twisted blades, and are arranged in the same direction of rotation as the long blades of the back blades and the short blades of the back blades.

[0015] Preferably, the outer diameters of the back blade long blade and the back blade short blade are the same as the outer diameter of the impeller.

[0016] Preferably, a pump chamber wall is provided on the outer side surfaces of the long back blade and the short back blade, and a gap exists between the long back blade and the short back blade and the pump chamber wall.

[0017] Preferably, the distance between the long back blade and the short back blade and the pump chamber wall is s, the height of the long back blade and the short back blade is t, and the ratio of s to t ranges from 0.1 to 0.3.

[0018] As a preference, the long blade curvature radius of the back blade is R a , the curvature radius of the short blade of the back blade is R b , and the curve radius of the back blade long blade and the back blade short blade close to the hub is R c , and R b With R a The ratio ranges from 0.8 to 1.2, R c =3 to 5mm.

[0019] Preferably, the length of the short blade of the back blade is 0.6 to 0.9 times that of the long blade of the back blade.

[0020] Compared with the prior art, the beneficial effects of the utility model are:

[0021] The back blade of the utility model is in the form of a curved blade similar to the shape of the main blade. When the fluid flows into the back blade through the cavity, the main blade and the back blade rotate coaxially. On the one hand, the axial force on the impeller rear cover plate can be reduced. On the other hand, compared with the straight blade of the back blade, the pump efficiency is not reduced much and the shaft power is increased less.

[0022] The utility model only adds long and short blade curved back blades to the long and short blade impeller without changing other components of the centrifugal pump, which can greatly reduce the axial force and has little effect on the external characteristics of the centrifugal pump. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a front view schematic diagram of the overall structure of an embodiment of the utility model.

[0024] Figure 2 The figure is a top view schematic diagram of the overall structure of an embodiment of the utility model.

[0025] Figure 3 The figure is a schematic cross-sectional view of the overall structure of an embodiment of the utility model.

[0026] Figure 4 for Figure 3 A partial enlarged view of part A in the middle.

[0027] In the figure: back blade long blade 1, back blade short blade 2, impeller body 3, impeller front cover 3.1, impeller main blade 3.2, impeller rear cover 3.3, wheel hub 3.4, pump chamber wall 3.5, back blade long blade curvature radius R a , back blade short blade curvature radius R b , back blade length, short blade outlet fillet radius R c , back blade height t, distance between back blade and pump chamber wall s. DETAILED DESCRIPTION

[0028] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0029] A centrifugal pump is a pump that uses the centrifugal force generated by the rotation of the impeller to transport liquid. Its working principle is that before the water pump is started, the pump housing and the water suction pipe must be filled with water, and then the motor is started so that the pump shaft drives the impeller and water to rotate at high speed. At this time, the water is thrown to the outer edge of the impeller under the action of centrifugal force, and flows into the water pressure pipeline of the water pump through the flow channel of the volute pump housing, thereby realizing the transportation of liquid.

[0030] The basic structure of a centrifugal pump includes impeller, pump body, pump shaft, bearing, sealing ring and stuffing box. The impeller is the core part of the centrifugal pump. It has high speed and high output. The design of the blades allows water to move centrifugally smoothly. The pump body plays a supporting and fixing role and is connected to the bearing bracket. The pump shaft is connected to the motor through a coupling to drive the impeller to rotate.

[0031] During the operation of a centrifugal pump, due to the rotation of the impeller, axial force will inevitably be generated. As the requirements for stable operation of the centrifugal pump gradually increase, the axial force balance problem becomes more and more important. Especially for long-short blade impellers, since the main blade structure is a long blade plus a short blade structure, the axial force has a greater impact. Generally, clean water pumps use a seal plus a balancing hole structure to balance the axial force, but for the transportation of fluids containing impurities, it is more common to use a back blade structure to balance the axial force. While balancing the axial force, the back blade is also very effective in preventing impurities from entering the shaft seal.

[0032] Centrifugal pumps have the advantages of high head, small flow rate, and reliable use. They are widely used in chemical, petroleum, papermaking, water supply and drainage, road drainage, farmland irrigation, boiler water supply, laboratories and medical equipment. Whether it is transporting chemical liquids such as acid and alkali liquids, crude oil, and pulp, or used in urban water supply and drainage, road drainage, and farmland irrigation, centrifugal pumps can play an important role.

[0033] However, the current back blade design requires a small axial gap between it and the wall of the non-rotating component to ensure the normal rotation of the impeller. However, the existence of this gap also has a certain impact on the balance of the axial force. In order to solve the above problem, the present embodiment 1 and the present embodiment 2 are provided.

[0034] Reference Figure 1 and Figure 4 For this embodiment 1, Figure 1 is a schematic front view of the overall structure of this embodiment 1, Figure 2 is a schematic top view of the overall structure of this embodiment 1, Figure 3It is a cross-sectional schematic diagram of the overall structure of this embodiment 1. This embodiment 1 is a long-short blade back blade structure, including an impeller body, the impeller body includes a hub, an impeller rear cover plate is fixed to the outer periphery of the hub, one side of the impeller rear cover plate is provided with impeller main blades, the outer side of the impeller blades is an impeller front cover plate, and the other side of the impeller rear cover plate is fixed with back blade long blades and back blade short blades, and the back blade long blades and back blade short blades are alternately arranged on the side of the impeller rear cover plate and distributed circumferentially along the axis.

[0035] In addition, the design of this long-short blade back blade structure also fully considers the principles of fluid dynamics. The alternating arrangement of long back blades and short back blades not only increases the surface area of ​​the impeller, allowing the fluid to be more evenly distributed on the impeller and improving the fluidity of the impeller, but also reduces the vortex and resistance generated by the fluid inside the impeller, reducing energy loss.

[0036] In addition, the structure also has high structural strength and stability. Through a carefully designed fixing method, the long back blade and the short back blade can be firmly fixed on the impeller rear cover to avoid loosening or falling off during high-speed rotation. This design not only ensures the long-term stable operation of the impeller, but also reduces the cost of maintenance and replacement.

[0037] In practical applications, this impeller with a long-short blade back-blade structure has shown excellent performance. Whether in high or low flow conditions, it can maintain high efficiency and stability to meet the needs of various fluid transportation and processing.

[0038] Reference Figure 1 and Figure 2 The long back blade and the short back blade are both curved cylindrical blade structures and are integrally formed with the impeller rear cover. This design ensures that the long back blade and the short back blade can stably follow the rotation of the impeller during rotation and effectively guide the fluid through. Their integrally formed structure with the impeller rear cover not only enhances the stability and reliability of the overall structure, but also improves the durability of the blades.

[0039] In addition, the curved design of the long back blade and the short back blade enables them to better adapt to the flow characteristics of the fluid in the impeller. This structure takes into account the characteristics of both the curved blades and the columnar blades, and can greatly reduce the axial force of the long and short blade impellers. Compared with the straight column back blades, it can reduce the increase in shaft power and ensure the efficiency performance of the centrifugal pump.

[0040] The combination of long back blades and short back blades ensures efficient fluid transmission at different flow rates and pressures. This design also helps reduce turbulence and eddy currents in the impeller, thereby improving the efficiency and performance of the entire system.

[0041] At the same time, due to the cylindrical shape of the back blade long blade and the back blade short blade, they can generate a certain centrifugal force when rotating, which helps to distribute the fluid more evenly around the impeller. This distribution uniformity can not only reduce the impact and wear of the fluid on the blades, but also reduce the vibration and noise of the system.

[0042] The long blades and the short blades of the back blade are equally spaced and arranged in a spiral shape with the center of the impeller as the center. This structure enables the impeller to effectively guide the fluid to flow continuously and smoothly when rotating at high speed. The staggered layout of the long blades and the short blades not only increases the surface area of ​​the impeller, thereby increasing the contact area of ​​the fluid, but also achieves precise control of the flow rate and flow direction of the fluid by changing the length and angle of the blades.

[0043] As the fluid passes through the impeller, the long blades, due to their larger surface area, are able to capture more fluid and guide it to flow in a predetermined direction. The short blades, by virtue of their shorter length and steeper angle, effectively accelerate the fluid and push it to the next long blade. As a result of this alternating action, the fluid is evenly distributed and effectively pushed inside the impeller, thus achieving efficient fluid delivery.

[0044] In addition, this spiral circumferentially evenly spaced blade design also has excellent self-cleaning capabilities. Since there is enough space between the blades, the fluid can naturally wash away the impurities attached to the blade surface when passing through, thereby reducing the maintenance cost and service life of the impeller.

[0045] The main blades of the impeller are twisted blades, and are arranged in the same rotation direction as the long blades of the back blades and the short blades of the back blades.

[0046] The twisted blade design not only increases the impeller's rotation efficiency, but also enables it to maintain stable performance at high speeds. The combination of long back blades and short back blades not only strengthens the impeller's structural strength, but also plays a balancing role during the rotation process, reducing vibration and noise caused by high-speed rotation.

[0047] This design enables the impeller to fully exert its efficiency when working, and it can show excellent performance whether it is used as a driving force for fluid transportation or as a key component for energy conversion. At the same time, the setting of the same direction of rotation also ensures the stability and reliability of the entire system, allowing the entire mechanical system to operate more efficiently and safely.

[0048] The outer diameters of the back blade long blade and the back blade short blade are the same as the outer diameter of the impeller.

[0049] In addition, the design of the back blade long blade and the back blade short blade also fully considers the principles of fluid dynamics to ensure that they can effectively guide the fluid during rotation and reduce energy loss. The back blade long blade, with its longer length, can more effectively capture and push the fluid, improving the overall efficiency of the pump. The back blade short blade optimizes the internal space layout of the pump through its compact structure, further improving the compactness and stability of the pump.

[0050] In addition, in order to further enhance the performance and reliability of the pump, the back blade long blade and the back blade short blade are made of high-strength and wear-resistant materials, which can withstand the pressure caused by high-speed rotation and fluid impact, thereby ensuring the stability and durability of the pump during long-term operation.

[0051] The outer side surfaces of the long back blade and the short back blade are provided with a pump chamber wall, and there is a gap between the long back blade and the short back blade and the pump chamber wall. The pump chamber wall not only provides a stable support for the long back blade and the short back blade, but also ensures the sealing of the inside of the pump body, effectively preventing the leakage of the medium. In addition, the gap between the long back blade and the short back blade and the pump chamber wall has been precisely calculated and designed, which not only ensures the normal operation of the pump, but also reduces the energy consumption caused by friction. These gaps also play a role in cooling and lubrication. During the operation of the pump body, the medium flows in the gap, which not only takes away part of the heat and reduces the temperature of the pump body, but also provides lubrication for the blades and the pump chamber wall, reduces the wear caused by friction, and thus extends the service life of the pump.

[0052] exist Figures 1 to 4 Based on the main shape, structure, position relationship, connection relationship, design parameters and other technical solutions in Example 1, the present Example 2 is obtained according to the actual installation verification. The present Example 2 is also a long and short blade back blade structure. Figure 3 and Figure 4 , including impeller main blades, back blade long blades, back blade short blades, hub, pump chamber, impeller rear cover plate, the front side of the impeller rear cover plate has 5 back blade long blades, between every two back blade long blades there is a back blade short blade, the back blade long blades and the back blade short blades are evenly distributed relative to the circumference of the axis of the impeller body. The back blade long blades and the back blade short blades on the rear side of the impeller rear cover plate are collectively referred to as back blades. The length of the back blade short blade is 0.82 times the length of the back blade long blade. The radius of curvature of the back blade long blade is R a, the curvature radius of the short blade of the back blade is R b The average thickness of the back blade is d, and the radius of the back blade long blade and the back blade short blade close to the hub (i.e. the back blade outlet) is R c The impeller blades on the front side of the impeller rear cover are the main impeller blades, which are twisted blades, and the back blades on the back side of the impeller rear cover are cylindrical blades. The outer diameter of the back blade is consistent with the outer diameter of the impeller body, and a gap is left between the back blade and the pump chamber wall to ensure the normal rotation of the impeller.

[0053] Five long back blades are added on the rear side of the impeller rear cover, and a short back blade is provided between every two long back blades. The long back blades and the short back blades are evenly distributed relative to the circumference of the axis of the impeller body. The long back blades and the short back blades added on the rear side of the impeller rear cover are a new back blade structure, which can greatly reduce the axial force of the long and short blade impeller; secondly, since the back blade adopts a curved blade similar to the main blade of the impeller, compared with the straight cylindrical back blade, the increase in shaft power can be reduced to ensure the efficiency performance of the centrifugal pump; at the same time, the height of the back blade is t, the distance between the back blade and the pump chamber wall is s, and x=s / t is denoted as a dimensionless parameter. After comparing different x values, it is found that the balancing axial force effect is best in the range of x=0.1 to 0.3, and the effect on efficiency and shaft power is small.

[0054] The beneficial effects produced by the present embodiment 1 and the present embodiment 2 are:

[0055] The back blade of this embodiment is in the form of a curved blade with a similar shape to the main blade. When the fluid flows into the back blade through the cavity, the main blade and the back blade rotate coaxially. On the one hand, the axial force on the impeller rear cover plate can be reduced. On the other hand, compared with the straight blade of the back blade, the pump efficiency is not reduced much and the shaft power is increased less.

[0056] In this embodiment, without changing other components of the centrifugal pump, only long and short blade curved back blades are added to the long and short blade impeller, which can significantly reduce the axial force and has little effect on the external characteristics of the centrifugal pump.

[0057] In addition to the above-mentioned embodiments, within the scope disclosed in the claims and the specification of the utility model, the technical features or technical data of the utility model can be reselected and combined to form new embodiments, which should also be regarded as specific embodiments of the utility model and within the protection scope of the utility model.

Claims

1. A long and short blade back blade structure, characterized in that: The impeller body comprises an impeller hub, an impeller rear cover plate is fixed to the outer periphery of the hub, one side of the impeller rear cover plate is provided with an impeller main blade, the outer side of the impeller blade is an impeller front cover plate, and the other side of the impeller rear cover plate is fixed with a back blade long blade and a back blade short blade, and the back blade long blade and the back blade short blade are alternately arranged on the side of the impeller rear cover plate and distributed on the circumference of the axis; The long back blade and the short back blade are both curved cylindrical blade structures, and a pump cavity wall is arranged on the outer side surfaces of the two. There is a gap between the long back blade and the short back blade and the pump cavity wall.

2. The long and short blade back blade structure according to claim 1, characterized in that: The long back blades and the short back blades are integrally formed with the impeller rear cover plate, and the long back blades and the short back blades are evenly distributed around the circumference of the axis of the impeller body.

3. The long and short blade back blade structure according to claim 1, characterized in that: The impeller body is circular, and the long back blades and the short back blades are equidistantly distributed in a spiral circle with the center of the impeller as the center.

4. The long and short blade back blade structure according to claim 1, characterized in that: The main blades of the impeller are twisted blades, and are arranged in the same rotation direction as the long blades of the back blades and the short blades of the back blades.

5. The long and short blade back blade structure according to claim 3, characterized in that: The outer diameters of the back blade long blade and the back blade short blade are the same as the outer diameter of the impeller.

6. The long and short blade back blade structure according to claim 1, characterized in that: The front side of the impeller rear cover is provided with a plurality of long back blades, the rear side of the impeller rear cover is provided with a plurality of long back blades, and a short back blade is provided between every two long back blades.

7. The long and short blade back blade structure according to claim 6, characterized in that: The distance between the long back blade and the short back blade and the pump chamber wall is s, the height of the long back blade and the short back blade is t, and the ratio of s to t ranges from 0.1 to 0.

3.

8. The long-short blade back blade structure according to claim 1, wherein the curvature radius of the long blade of the back blade is R a , the curvature radius of the short blade of the back blade is R b , and the curve radius of the back blade long blade and the back blade short blade close to the hub is R c , and R b With R a The ratio ranges from 0.8 to 1.2, R c =3 to 5mm.

9. The long-short blade back blade structure according to any one of claims 1 to 7, characterized in that: The length of the short blade of the back blade is 0.6 to 0.9 times that of the long blade of the back blade.

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