Low-axial-force multi-stage turbocharged axial flow pump

Abstract

The invention discloses a low-axial-force multi-stage turbocharging axial flow pump which comprises a motor, a pump cover and a pump shaft, a connecting flange with a water inlet and a water inlet is arranged on the opposite side of the pump cover, and a plurality of composite guide vane bodies which are arranged on the pump shaft in an empty sleeving mode are fixedly installed between the connecting flange and the pump cover. The composite guide vane body comprises a positioning sleeve, a vane fixing ring, an inner lantern ring, an outer flow deflector and an inner flow deflector, the positioning sleeve is fixedly connected with the pump cover and / or the end of the connecting flange, and the axial length of the positioning sleeve is larger than the axial length of the vane fixing ring and the axial length of the inner lantern ring; an axial flow impeller fixedly sleeved on the pump shaft is arranged in the positioning sleeve of each composite guide vane body, the axial flow impeller comprises an outer wheel column and an inner wheel column, a plurality of outer guide vanes are arranged on the outer wheel column, a plurality of inner guide vanes are arranged between the outer wheel column and the inner wheel column, and the outer guide vanes and the inner guide vanes are opposite in direction; a first flow guide annular channel and a second flow guide annular channel are formed in a shell formed by the pump cover, the composite guide vane body and the connecting flange.

Description

Technical Field

[0001] The invention relates to the field of water pumps, and in particular to an axial flow pump with low axial force and multi-stage turbocharging. Background Art

[0002] Axial flow pumps are mainly suitable for low head and large flow applications, such as water jet propulsion for ships, dock drainage, water level regulation of canal locks, etc. They are also often used as large circulating water pumps in power plants. Since the blades of axial flow pumps are usually cantilevered, they may suffer from strength problems such as fatigue failure when under heavy load and periodic unstable operation. On the other hand, with the development of society, higher requirements are placed on the reliability and stability of axial flow pumps, which need to meet the requirements of stable use under high speed and high load operation.

[0003] The existing axial flow pump mainly includes: a housing assembly, which is provided with a water inlet and a water outlet; a stator assembly, which is arranged in the housing assembly; a rotor assembly, which includes a cylindrical rotor body and blades, the rotor body is arranged in the stator assembly, the two ends of the rotor body are rotatably connected with the housing assembly, and a plurality of blades are arranged on the inner wall of the rotor body. After power is turned on, the rotor assembly can rotate relative to the stator assembly so that the blades drive the liquid from the water inlet to the water outlet. The two ends of the rotor body are rotatably connected with the housing assembly, so that the rotor body cannot move axially in the housing assembly and the stator assembly, which can improve the accuracy of the stator assembly and the rotor assembly, improve the rotation efficiency of the rotor assembly, and improve the liquid delivery efficiency. The water inlet and the water outlet of the above-mentioned axial flow pump are respectively arranged at the two ends of the axial direction, and the liquid is mainly driven to move in the axial direction by the blades on the rotor when the rotor rotates to reach the water outlet. Although this method has a short liquid delivery stroke, it requires a large speed to meet the axial thrust of the liquid, and the axial thrust generated by the rotor is mainly generated when several blades rotate, and the head is small.

[0004] In order to increase the head, a multi-stage axial pump is currently available, which includes a pump shaft, a plurality of guide vane bodies loosely sleeved on the pump shaft, and a plurality of axial flow impellers sleeved and fixed on the pump shaft. The guide vane bodies and the axial flow impellers are arranged at intervals on the pump shaft, and the guide vane bodies remain fixed when the pump shaft drives the axial flow impeller to rotate. Summary of the invention

[0005] In view of the above-mentioned deficiencies in the prior art, the object of the present invention is to provide a low axial force multi-stage turbocharged axial flow pump to solve the problem that the existing axial flow pumps generate a small head, and after the multi-stage axial flow pump is provided with multiple guide vanes and axial flow impellers, the axial length will be lengthened, thereby increasing the volume of the pump body.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solutions: A low axial force multi-stage turbocharged axial flow pump comprises a motor, a pump cover and a pump shaft, wherein the motor is fixedly connected to the pump cover, and the output end of the motor is fixedly connected to the pump shaft, a connecting flange with a water inlet and a water outlet is provided on the opposite side of the pump cover, at least one composite guide vane body which is hollowly sleeved on the pump shaft is fixedly installed between the connecting flange and the pump cover, the composite guide vane body comprises a positioning sleeve, a blade fixing ring and an inner sleeve ring which are concentrically arranged from outside to inside, the positioning sleeve is fixedly connected to the pump cover and / or the end of the connecting flange, the axial length of the positioning sleeve is greater than the axial length of the blade fixing ring and the inner sleeve ring, outer guide vanes and inner guide vanes which are evenly distributed in the circumferential direction are respectively provided between the positioning sleeve and the blade fixing ring, and between the blade fixing ring and the inner sleeve ring, the outer guide vanes and the inner guide vanes both spirally rise in the axial direction, and the spiral directions are opposite; at each composite guide vane, a plurality of guide vanes are provided, each of which has a plurality of guide vanes ... An axial flow impeller which is sleeved and fixed on the pump shaft is provided in the positioning sleeve of the body, and the axial flow impeller includes an outer wheel column and an inner wheel column which are arranged concentrically, and a plurality of outer guide vanes are evenly arranged on the outer end surface of the outer wheel column in the circumferential direction, and a plurality of inner guide vanes are circumferentially arranged between the outer wheel column and the inner wheel column, and the outer guide vanes and the inner guide vanes both spirally rise in the axial direction, and the spiral directions are opposite; the blade fixing ring is arranged correspondingly to the outer wheel column, and there is a gap at adjacent ends, and the blade fixing ring and the outer wheel column form a cylinder, and a first guide channel connected to the water inlet is formed between the outer side of the cylinder and the inner wall of the positioning sleeve and the inner side of the pump cover; the inner sleeve ring and the inner wheel column are arranged correspondingly, and there is a gap at adjacent ends, and the inner sleeve ring and the inner wheel column form a cylinder, and a second guide channel is formed between the outer wall of the cylinder and the inner wall of the cylinder, and the two ends of the second guide channel are respectively connected to the first guide channel and the water outlet. After the motor is started, the pump shaft rotates under the drive of the motor, and then drives the axial flow impeller sleeved thereon to rotate. During the rotation process, a pressure difference is formed inside and outside the sealed chamber formed by the positioning sleeve of the composite guide vane body, the pump cover and the connecting flange. Under this pressure difference, the liquid flows axially toward the axial flow impeller, and flows axially along the first guide ring channel under the guiding action of the outer guide vane at the first guide ring channel until it reaches the pump cover, and then is guided to the outlet on the same side of the water inlet under the reverse force of the inner guide vanes of each axial flow impeller. Since the spiral directions of the outer guide vanes and the inner guide vanes are different during the rotation of the axial flow impeller, but they are in synchronous rotation, the liquid flow directions generated in the first guide ring channel and the second guide ring channel are also opposite, which can not only make the axial force opposite during the flow of the fluid to reach a balanced state, but also make the liquid under the same flow axial length, through the different axial directions of the outer guide vanes and the inner guide vanes, the head generated is larger, compared with the axial flow pump with the same design parameters (flow rate, head), the axial length can be reduced by half. After arranging multiple axial flow impellers and composite guide vanes, the superposition of each stage head can achieve the boosting function without causing the rotor composed of the axial flow impeller and the pump shaft to be subjected to too much axial force.The positioning sleeve arranged on the composite guide vane body is connected between the pump cover and the connecting flange, and together with the pump cover and the connecting flange, forms the pump housing. At the same time, the axial impeller is covered in the positioning sleeve, and the overall structure is relatively compact. The outer guide vane and the inner guide vane arranged on the composite guide vane body can eliminate the fluid circulation and pressure diffusion, convert part of the velocity kinetic energy into pressure potential energy, and reduce flow loss. The inner sleeve ring corresponds to the inner wheel column, and the blade fixing ring corresponds to the outer wheel column, so that two interconnected annular flow channels can be formed in the pump housing to guide the fluid.

[0007] Furthermore, the inner wall of the pump cover is arc-shaped at the locations corresponding to the first flow guide annular channel and the second flow guide annular channel. After being arc-shaped, the location can facilitate the passage of fluid and can play a guiding role when the fluid passes through.

[0008] Furthermore, the water outlet is a straight-line channel connected to the second flow guide ring. The water outlet and the second flow guide ring are on the same axis. After the fluid enters the second flow guide ring from the first flow guide ring, it is directly discharged from the water outlet. The flow guide path is short and the fluid is discharged smoothly.

[0009] Furthermore, the water inlet is an annular water inlet channel, or a plurality of arc-shaped flow guide channels distributed on the connecting flange. When the water inlet is set to an annular shape, the space for external water flow to enter the pump is larger, and the introduction is smoother and faster. The method of setting the water inlet as a plurality of arc-shaped flow guide channels can also quickly introduce fluid into the pump body in a circumferential direction. Compared with the method of setting an annular water inlet channel, the water inlet is smaller, but compared with the method of setting one, the diversion speed is faster.

[0010] Furthermore, there is a gap between the end of the outer guide vane and the inner wall of the positioning sleeve, a connecting ring plate is provided at the connecting end of the positioning sleeve, and a connecting plate corresponding to the connecting ring plate is provided at the end where the pump cover and the positioning sleeve are connected. Adjacent positioning sleeves, the positioning sleeve and the pump cover, and the positioning sleeve and the connecting flange are all connected and fixed by fasteners. The gap between the outer guide vane and the inner wall of the positioning sleeve can prevent the outer end of the axial flow guide wheel from rubbing against the inner wall of the positioning sleeve when the axial flow guide wheel rotates, and the positioning sleeve Furthermore, the axial flow impeller and the pump shaft form a rotor, and the axial force of the rotor is zero. When the axial flow impeller rotates with the pump shaft, different axial forces will be generated between the outer blades and the fluid, and between the inner blades and the fluid. If the difference between the two is large, it will affect the stability of the rotor operation. When the forces between the two are equal or the difference is very small, the axial force is zero, the rotor operation stability is better, and the vibration and noise generated are lower.

[0011] Furthermore, a mounting frame connected to the pump cover and the connecting flange is provided. The mounting frame can provide support for the pump body so that it can be placed flat on the ground. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a structural schematic diagram of a multi-stage axial flow pump in the prior art; Figure 2 It is a structural schematic diagram of the multi-stage axial flow pump in Example 1; Figure 3 It is a structural schematic diagram of the multi-stage axial flow pump in Example 2; Figure 4 It is a schematic diagram of the structure of the multi-stage axial flow pump in Example 3; Figure 5 Schematic diagram of the structure of the axial flow impeller in the embodiment; Figure 6 Schematic diagram of the structure of the composite guide vane body in the embodiment; Figure 7 It is a comparison diagram of the total head performance curves of a conventional four-stage impeller axial flow pump and a two-stage booster impeller axial flow pump in this embodiment; Figure 8 It is a comparison diagram of the total axial force curves of a conventional four-stage impeller axial flow pump and a two-stage booster impeller axial flow pump in this embodiment. DETAILED DESCRIPTION

[0013] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. The components of the embodiments of the present invention generally described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work belong to the scope of protection of the present invention.

[0014] It should be noted that similar numbers and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further defined and explained in the subsequent drawings. In the description of the present invention, it should be noted that the orientation or position relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside", etc. is based on the orientation or position relationship shown in the drawings, or the orientation or position relationship in which the invention product is usually placed when used, which is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention. In addition, the terms "first", "second", "third", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance. In addition, the terms "horizontal", "vertical", etc. do not mean that the components are absolutely horizontal or suspended, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but can be slightly tilted. In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0015] Embodiment 1: like Figure 2 , Figure 5 , Figure 6As shown, in this embodiment, a low axial force multi-stage turbocharged axial flow pump is provided, comprising a motor 1, a pump cover 2 and a pump shaft, wherein the motor 1 is fixedly connected to the pump cover 2, and the output end of the motor 1 is fixedly connected to the pump shaft via a coupling (the pump shaft is vertically arranged), and a connecting flange 3 with a water inlet 31 and a water inlet 31 is provided on the opposite side of the pump cover 2, and a plurality of composite guide vane bodies 4 which are hollowly sleeved on the pump shaft are fixedly installed between the connecting flange 3 and the pump cover 2, and the composite guide vane body 4 comprises a positioning sleeve 41, a blade fixing sleeve 42, a blade fixing sleeve 43, a blade fixing sleeve 44, a blade fixing sleeve 45, a blade fixing sleeve 46, a blade fixing sleeve 47, a blade fixing sleeve 48, a blade fixing sleeve 49, a blade fixing sleeve 50, a blade fixing sleeve 51, a blade fixing sleeve 52, a blade fixing sleeve 53, a blade fixing sleeve 54, a blade fixing sleeve 55, a blade fixing sleeve 56, a blade fixing sleeve 57, a blade fixing sleeve 58, a blade fixing sleeve 59, a blade fixing sleeve 51, a blade fixing sleeve 52 ...0, a blade fixing sleeve 51, a blade fixing sleeve 52, a blade fixing sleeve 53, a blade fixing sleeve 54, a blade fixing sleeve 55, a blade fixing sleeve 56, a blade fixing sleeve 57 The positioning sleeve 41 is fixedly connected to the pump cover 2 and / or the end of the connecting flange 3. The axial length of the positioning sleeve 41 is greater than the axial length of the blade fixing ring 42 and the inner sleeve ring 43. An outer guide vane and an inner guide vane are respectively arranged between the positioning sleeve 41 and the blade fixing ring 42, and between the blade fixing ring 42 and the inner sleeve ring 43. The outer guide vane and the inner guide vane both spirally rise in the axial direction, and the spiral directions are opposite. An axial flow guide vane is provided in the positioning sleeve 41 of each composite guide vane body 4. The impeller 5, the axial flow impeller 5 and the pump shaft form a rotor, including an outer wheel column 51 and an inner wheel column 52 arranged concentrically (the axial heights of the outer wheel column 51 and the inner wheel column 52 are equal), a plurality of outer guide vanes 53 are evenly arranged on the outer end surface of the outer wheel column 51 in the circumferential direction, and a plurality of inner guide vanes 54 are arranged circumferentially between the outer wheel column 51 and the inner wheel column 52, the outer guide vanes 53 and the inner guide vanes 54 both spirally rise in the axial direction, and the spiral directions are opposite; the blade fixing ring 42 is arranged corresponding to the outer wheel column 51, and there is a gap between the adjacent ends (the gap is set at 0.5-1.5mm ), the blade fixing ring 42 and the outer wheel column 51 form a cylinder, and a first guide ring 6 connected to the water inlet 31 is formed between the outer side of the cylinder and the inner wall of the positioning sleeve 41 and the inner side of the pump cover 2; the inner ring 43 and the inner wheel column 52 are correspondingly arranged, and there is a gap between the adjacent ends (the gap is set between 0.5-1.5mm), the inner ring 43 and the inner wheel column 52 form a cylinder, and a second guide ring 7 is formed between the outer wall of the cylinder and the inner wall of the cylinder, and the two ends of the second guide ring 7 are respectively connected to the first guide ring 6 and the water outlet 32. After the motor 1 is started, the pump shaft rotates under the drive of the motor 1, thereby driving the axial flow impeller 5 sleeved thereon to rotate. During the rotation process, a pressure difference is formed inside and outside the sealed chamber formed by the positioning sleeve 41 of the composite guide vane body 4 and the pump cover 2 and the connecting flange 3. Under this pressure difference, the liquid flows axially toward the axial flow impeller 5, and flows axially along the first guide ring channel 6 under the guiding action of the outer guide vanes 53 at the first guide ring channel 6 until it reaches the pump cover 2, and then is guided to the water outlet 32 ​​on the same side as the water inlet 31 under the reverse force of the inner guide vanes 54 of each axial flow impeller 5.Since the spiral directions of the outer guide vane 53 and the inner guide vane 54 are different during the rotation of the axial flow impeller 5, but they are in synchronous rotation, the liquid flow directions generated by the first guide ring 6 and the second guide ring 7 are also opposite, which can not only make the axial force opposite during the flow of the fluid to reach a balanced state, but also make the liquid under the same flow axial length, through the different axial diversion of the outer guide vane 53 and the inner guide vane 54, the head generated is larger, compared with the axial flow pump with the same design parameters (flow rate, head), the axial length can be reduced by half. After arranging multiple axial flow impellers 5 and composite guide vane bodies 4, each level of head is superimposed, and the supercharging function can be achieved, and the rotor composed of the axial flow impeller 5 and the pump shaft will not be subjected to too much force in the axial direction. The positioning sleeve 41 arranged on the composite guide vane body 4 is connected between the pump cover 2 and the connecting flange 3, and together with the pump cover 2 and the connecting flange 3, it forms a pump housing. At the same time, the axial flow impeller 5 is covered in the positioning sleeve 41, and the overall structure is relatively compact. The outer guide vanes and inner guide vanes provided on the composite guide vane body 4 can eliminate the fluid circulation and pressure diffusion, convert part of the velocity kinetic energy into pressure potential energy, and reduce flow loss. The inner sleeve ring 43 and the inner wheel column 52 are provided correspondingly, and the blade fixing ring 42 and the outer wheel column 51 correspond to form two interconnected annular flow channels in the pump housing for fluid guidance.

[0016] like Figure 2 As shown, the inner wall of the pump cover 2 is arc-shaped (arch-shaped in this embodiment to facilitate fluid diversion) at the corresponding first guide ring 6 and second guide ring 7. An L-shaped channel or at least two evenly distributed L-shaped channels are provided at the side end of the connecting flange 3, and the L-shaped channel forms the water inlet 31. In a specific implementation, more than two L-shaped channels can be provided, and the L-shaped channels are connected to the first guide ring 6. After this place is set to an arc, it is convenient for the fluid to pass through, and it can play a guiding role when the fluid passes through. The radial cross-section of the outer guide vane 53 and the inner guide vane 54 in this embodiment is airfoil-shaped, that is, thick in the middle and slightly thin on both sides.

[0017] The water outlet 32 ​​on the connecting flange 3 is a straight-line channel connected to the second flow guide ring 7, and has a circular shape and the same diameter as the second flow guide ring 7. The water outlet 32 ​​and the second flow guide ring 7 are on the same axis. After the fluid enters the second flow guide ring 7 from the first flow guide ring 6, it is directly discharged from the water outlet 32. The flow guide path is short and the fluid is discharged smoothly.

[0018] Furthermore, there is a gap between the end of the outer guide vane 53 and the inner wall of the positioning sleeve 41, a connecting ring plate is provided at the connecting end of the positioning sleeve 41, and a connecting plate corresponding to the connecting ring plate is provided at the end where the pump cover 2 and the positioning sleeve 41 are connected. Adjacent positioning sleeves 41, the positioning sleeve 41 and the pump cover 2, and the positioning sleeve 41 and the connecting flange 3 are all connected and fixed by fasteners. The gap between the outer guide vane 53 and the inner wall of the positioning sleeve 41 can prevent the outer end of the axial flow guide wheel from rubbing against the inner wall of the positioning sleeve 41 when the axial flow guide wheel rotates, and the positioning sleeve 41 Furthermore, the axial flow impeller 5 and the pump shaft form a rotor, and the axial force of the rotor is zero. When the axial flow impeller 5 rotates with the pump shaft, different axial forces will be generated between the outer blades and the fluid, and between the inner blades and the fluid. If the difference between the two is large, it will affect the stability of the rotor operation. When the forces between the two are equal or the difference is very small, the axial force is zero, the rotor operation stability is better, and the vibration and noise generated are lower.

[0019] Further, a mounting stand connected thereto is provided on both the pump cover 2 and the connecting flange 3. The mounting stand can provide support for the pump body so that it can be placed flat on the ground.

[0020] A conventional four-stage impeller axial flow pump is compared with the two-stage axial flow pump in the embodiment (since the axial flow impeller in this embodiment is a double-layer impeller, the first-stage impeller is equivalent to the conventional two-stage impeller, that is, Figure 7 , Figure 8 Medium and low axial force design), wherein the total axial length of the multi-stage axial flow pump in this embodiment is approximately 3 / 4 of the total length of a conventional four-stage impeller axial flow pump, and the radial dimension is slightly larger than that of a conventional axial flow pump.

[0021] Through CFD simulation, the head and efficiency of the conventional four-stage impeller axial flow pump and the four-stage axial flow pump in this application are predicted, and the force of the axial fluid acting on the impeller wall is counted as the rotor water thrust, and the total rotor axial force Fz is calculated (as shown in the following table, the positive and negative axial force values ​​represent the direction, and the absolute value represents the magnitude of the axial force). Performance comparison curve and axial force comparison curve are shown in the figure below. Figure 7 , Figure 8 As shown, Figure 7 This is a comparison chart of the total head performance curves of the axial flow pump in this embodiment and the conventional axial flow pump. Figure 8 This is a comparison chart of the axial force between the axial flow pump in this embodiment and the conventional axial flow pump.

[0022] Simulation performance data comparison table From the head and efficiency comparison curve (refer to Figure 7 , Figure 8) It can be seen that under the rated point condition, the head of the low axial force multi-stage axial flow pump in this embodiment can meet the design requirements, and the efficiency is slightly lower than the multi-stage axial flow pump designed by the conventional method, while the axial force received is much lower than the conventional four-stage impeller axial flow pump.

[0023] Specifically, it can be seen from the axial force comparison curve that the axial force obtained by the rated point simulation calculation is slightly higher than the designed axial force. Compared with the axial flow pump designed by the conventional design method, the axial force on the rotor of the axial flow pump designed by the low axial force hydraulic design method is lower at 0.2 times the rated working condition (0.2Qopt, Qopt is the rated working condition flow) ~ 1.4 times the rated working condition (1.4Qopt); under the rated working condition, the axial force on the axial flow pump designed by the low axial force design method is about 1 / 4 of the axial flow pump designed by the conventional design method, and at 0.2 Qopt working condition, it is only 1 / 5 of the axial force on the axial flow pump designed by the conventional design method. The lower the axial force, the higher the structural reliability and stability. The axial length of the axial flow pump in this embodiment is also smaller than that of the conventional axial flow pump, with lower axial force and smoother operation. In the axial flow pumps of the same level, the axial length is smaller, the head is similar, and it is more convenient for transportation.

[0024] Example 2 like Figure 3 As shown, the difference between the axial flow pump in this embodiment and the embodiment 1 is that the structure of the connecting flange 3 is different. Specifically, the connecting flange 3 in this embodiment includes a connecting tube whose middle part is connected to the positioning sleeve 41 at the bottom and a water guide pipe connected to the lower end of the connecting tube. The connecting tube is concentric with the positioning sleeve 41, and the inner diameter is equal to the second diversion channel. The connecting tube is connected and fixed together by a connecting rod. An annular water inlet channel is formed between the connecting tube and the positioning sleeve 41, and the annular water inlet channel is the water inlet 31; the inner hollow part of the connecting tube and the water guide pipe forms the water outlet 32. After the water inlet 31 is set as an annular shape, the space for the external water flow to enter the pump is larger, and the introduction is smoother and faster. The method of setting the water inlet 31 as multiple arc-shaped diversion channels can also quickly introduce fluid into the pump body in a circumferential direction. Compared with the method of setting an annular water inlet channel, the water inlet 31 is smaller, but compared with the method of setting one, the diversion speed is faster.

[0025] Example 3 like Figure 4 As shown, the axial flow pump in this embodiment has the same structure as that in Embodiment 1, the only difference being that the axial flow pump in this embodiment is arranged transversely and is a horizontal axial flow pump.

[0026] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the technical solution. Those skilled in the art should understand that those modifications or equivalent substitutions of the technical solution of the present invention that do not depart from the purpose and scope of the technical solution should be included in the scope of the claims of the present invention.

Claims

1. A low axial force multi-stage turbocharged axial flow pump, comprising a motor, a pump cover and a pump shaft, wherein the motor is fixedly connected to the pump cover, and the output end of the motor is fixedly connected to the pump shaft, characterized in that: A connecting flange with a water inlet and a water inlet is provided on the opposite side of the pump cover, and at least one composite guide vane body with an empty sleeve on the pump shaft is fixedly installed between the connecting flange and the pump cover, and the composite guide vane body comprises a positioning sleeve, a blade fixing ring and an inner sleeve ring which are concentrically arranged from the outside to the inside, and the positioning sleeve is fixedly connected to the pump cover and / or the end of the connecting flange, and the axial length of the positioning sleeve is greater than the axial length of the blade fixing ring and the inner sleeve ring, and outer guide vanes and inner guide vanes which are evenly distributed in the circumferential direction are respectively provided between the positioning sleeve and the blade fixing ring, and between the blade fixing ring and the inner sleeve ring, and the outer guide vanes and the inner guide vanes both spirally rise in the axial direction, and the spiral directions are opposite; an axial flow impeller which is sleeved and fixed on the pump shaft is provided in the positioning sleeve of each composite guide vane body, and the axial The impeller comprises an outer wheel column and an inner wheel column which are arranged concentrically, a plurality of outer guide vanes are evenly arranged on the circumference of the outer end surface of the outer wheel column, a plurality of inner guide vanes are arranged circumferentially between the outer wheel column and the inner wheel column, the outer guide vanes and the inner guide vanes both spirally rise in the axial direction, and the spiral directions are opposite; the blade fixing ring is arranged correspondingly to the outer wheel column, adjacent ends have a gap, the blade fixing ring and the outer wheel column form a cylinder, the outer side of the cylinder and the inner wall of the positioning sleeve and the inner side of the pump cover form a first guide ring connected to the water inlet; the inner sleeve ring and the inner wheel column are arranged correspondingly, adjacent ends have a gap, the inner sleeve ring and the inner wheel column form a cylinder, a second guide ring is formed between the outer wall of the cylinder and the inner wall of the cylinder, and the two ends of the second guide ring are respectively connected to the first guide ring and the water outlet.

2. The low axial force multi-stage turbocharged axial flow pump according to claim 1, characterized in that: The inner wall of the pump cover is arc-shaped at locations corresponding to the first flow guide ring channel and the second flow guide ring channel.

3. The low axial force multi-stage turbocharged axial flow pump according to claim 1 or 2, characterized in that: The water outlet is a straight-line channel connected to the second flow guide ring channel.

4. The low axial force multi-stage turbocharged axial flow pump according to claim 3, characterized in that: The water inlet is an annular water inlet channel, or a plurality of arc-shaped flow guide channels distributed on the connecting flange.

5. The low axial force multi-stage turbocharged axial flow pump according to claim 1, 2 or 4, characterized in that: There is a gap between the end of the outer guide vane and the inner wall of the positioning sleeve. A connecting ring plate is provided at the connecting end of the positioning sleeve. A connecting plate corresponding to the connecting ring plate is provided at the end where the pump cover and the positioning sleeve are connected. Adjacent positioning sleeves, the positioning sleeve and the pump cover, and the positioning sleeve and the connecting flange are all connected and fixed by fasteners.

6. The low axial force multi-stage turbocharged axial flow pump according to claim 5, characterized in that: The axial flow impeller and the pump shaft form a rotor together, and the axial force of the rotor is zero.

7. The low axial force multi-stage turbocharged axial flow pump according to claim 6, characterized in that: A mounting stand connected to the pump cover and the connecting flange is provided.

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