Centrifugal pump capable of being used in total lift and centrifugal pump system

Abstract

The invention discloses a centrifugal pump capable of being used in a full-lift mode and a centrifugal pump system, relates to the technical field of centrifugal pumps, and mainly aims at solving the problem that an existing centrifugal pump can only meet the high-lift using working condition or the low-lift using working condition. Six long blades and six short blades are arranged in a closed impeller of the centrifugal pump at equal intervals in a staggered mode. The centrifugal pump system comprises a first centrifugal pump and a second centrifugal pump, a water inlet pipe and a water outlet pipe are connected to the first centrifugal pump, the second centrifugal pump communicates with the water inlet pipe through a water inlet branch pipe, and a three-way control valve is arranged on the water outlet pipe and communicates with the second centrifugal pump through a communicating branch pipe. A water outlet pipe on the output side of the three-way control valve communicates with the second centrifugal pump through a water outlet branch pipe. According to the centrifugal pump capable of being used in the total lift and the centrifugal pump system, the centrifugal pump can meet the total lift use working condition at the same time, the system can provide larger lift, and the use requirements of low lift and large flow can be met.

Description

Technical Field

[0001] The invention relates to the technical field of servo valves, and in particular to a centrifugal pump capable of being used at full head and a centrifugal pump system. Background Art

[0002] Centrifugal pumps are the most commonly used liquid transport power machinery today due to their simple and durable structure, reliable use, high efficiency, large flow rate and low cost. Based on the working principle of centrifugal pumps, there are also corresponding centrifugal pump characteristic curves. The calibration parameters of centrifugal pumps are the flow rate and head parameters corresponding to the centrifugal pump at the highest efficiency point. In actual use, the working parameters of centrifugal pumps do not deviate too much from the calibration parameters and are in a reasonable working range.

[0003] At present, centrifugal pumps are widely used in real life production. Their large flow and high efficiency characteristics are applicable to various real life production. However, the highest efficiency of conventional centrifugal pumps is only shown within the range of rated head. If it exceeds the upper limit of the range and then rises, the head will not rise any further; if it exceeds the lower limit of the range and then falls, although the flow will increase, the current will rise even more, so the effective power of the motor cannot be tolerated, it will be seriously overloaded, and even burn the motor.

[0004] This results in the existing centrifugal pumps being able to only meet high-head operating conditions or low-head operating conditions - centrifugal pumps suitable for high-head will be overloaded when used in the low-head stage; centrifugal pumps suitable for low-head have a low upper limit for their head and cannot reach it in the high-head stage.

[0005] At the same time, the existing horizontal centrifugal pumps have high efficiency and large flow in the medium and low head stages, but their efficiency decreases in the high head area; and although the existing horizontal multi-stage centrifugal pumps have high efficiency in the medium and high head stages, they cannot show the advantage of large flow in the low head area. Summary of the invention

[0006] The object of the present invention is to provide a centrifugal pump which can be used at full head, can meet both high head use conditions and low head use conditions, and has high efficiency.

[0007] Another object of the present invention is to provide a centrifugal pump system using the above centrifugal pump, which can provide a larger head and can meet the use requirements of low head and large flow.

[0008] The technical solution of the present invention to solve the previous technical problem is: a centrifugal pump and a centrifugal pump system that can be used at full head, including a volute, a closed impeller and a driving motor, the volute is provided with a volute water outlet pipe and a volute water inlet, the closed impeller is provided with an impeller water inlet, and a motor shaft mounting port is coaxially provided on the inner side of the impeller water inlet, the closed impeller is provided with six long blades and six short blades rotationally symmetrically arranged around its axis, the long blades and the short blades are equidistantly staggered, and the long blades and the short blades are both extended in an arc direction from the edge of the closed impeller toward its axis.

[0009] As a further improvement of the present invention, the inner diameter of the volute is 174 mm, the diameter of the volute water inlet is 52 mm, the length of the volute water outlet pipe is 90 mm, the diameter of its inlet end is 25 mm, and the diameter of the water outlet end is 40 mm.

[0010] As a further improvement of the present invention, the diameter of the closed impeller is 173 mm, the diameter of the impeller water inlet is 51 mm, the adjacent long blades and short blades form an impeller water outlet channel with a width of 7 mm and connected to the inner cavity of the volute, and the diameter of the motor shaft mounting port is 10 mm.

[0011] As a further improvement of the present invention, the volute water outlet pipe is tangentially arranged on the edge of the volute along the outer edge of the volute, the volute water inlet is arranged at the axis center of one side wall of the volute, and the closed impeller is coaxially arranged with the volute and rotatably installed inside the volute.

[0012] As a further improvement of the present invention, the impeller water inlet is arranged at the axis of the side wall of the closed impeller close to the volute water inlet.

[0013] As a further improvement of the present invention, the drive motor is arranged on one side of the volute, and the output shaft of the drive motor passes through the side wall of the volute and is fixedly connected to the motor shaft mounting opening.

[0014] The technical solution of the present invention to solve the second technical problem is: a centrifugal pump system using the above centrifugal pump, comprising a first centrifugal pump and a second centrifugal pump coaxially arranged and connected to each other, wherein the volute water inlets of the first centrifugal pump and the second centrifugal pump are respectively located on the opposite sides of the first centrifugal pump and the second centrifugal pump, and the closed impellers of the first centrifugal pump and the second centrifugal pump are arranged in opposite directions;

[0015] The volute water inlet of the first centrifugal pump is connected to an inlet pipe, the volute water inlet of the second centrifugal pump is connected to the inlet pipe through an inlet branch pipe, and an inlet branch switch valve is installed on the inlet branch pipe; the volute water outlet pipe of the first centrifugal pump is connected to an outlet pipe, and a three-way control valve is provided on the outlet pipe. The three-way control valve is also connected to the volute water inlet of the second centrifugal pump through a connecting branch pipe, and the outlet pipe on the output side of the three-way control valve is connected to the volute water outlet pipe of the second centrifugal pump through the outlet branch pipe.

[0016] As a further improvement of the present invention, there is only one driving motor.

[0017] As a further improvement of the present invention, the drive motor is arranged on a side of the first centrifugal pump away from the second centrifugal pump, and the output shaft of the drive motor passes through the first centrifugal pump and extends into the second centrifugal pump, and the closed impellers in the first centrifugal pump and the second centrifugal pump are fixedly connected to the output shaft of the drive motor through the motor shaft mounting port.

[0018] As a further improvement of the present invention, a main switch valve is provided on the input end of the water inlet pipe, and the water inlet branch pipe is arranged on the water inlet pipe on the output side of the main switch valve.

[0019] Beneficial Effects

[0020] Compared with the prior art, the centrifugal pump and centrifugal pump system of the present invention that can be used at full head have the following advantages:

[0021] 1. Compared with the existing centrifugal pump, the centrifugal pump in this scheme adopts a structure in which six long blades and six short blades are arranged equidistantly and staggered, and both the long blades and the short blades are extended in an arc direction from the edge of the closed impeller toward its axis. By superimposing the pressure of the six long blades and the six short blades, the head range of the centrifugal pump can be effectively improved, thereby being able to meet both high-head and low-head operating conditions at the same time, and having high efficiency.

[0022] 2. Compared with the existing centrifugal pump, the inner diameter of the volute of the centrifugal pump is 174mm, the diameter of the volute water inlet is 52mm, the length of the volute water outlet pipe is 90mm, and the diameter of its inlet end is 25mm, and the diameter of the water outlet end is 40mm; at the same time, the diameter of the closed impeller is 173mm, the diameter of the impeller water inlet is 51mm, the width of the impeller water outlet channel is 7mm, and the diameter of the motor shaft mounting port is 10mm; through the parameter design of the centrifugal pump in this scheme, excessive flow suction can be effectively avoided, thereby reducing power consumption, so that the power consumed by the centrifugal pump is kept within the effective range of the motor during the entire full-stroke stage.

[0023] 3. In the centrifugal pump system, the series / parallel switching of the first centrifugal pump and the second centrifugal pump can be realized by opening / closing the water inlet branch switch valve and switching the three-way control valve; when the system is used in the low-lift stage, the first centrifugal pump and the second centrifugal pump are connected in parallel, and the flow rate reaches the sum of the two pumps, and the motor power remains unchanged; when the system is used in the high-lift stage, when the first centrifugal pump and the second centrifugal pump are connected in series, the head can reach the sum of the first centrifugal pump and the second centrifugal pump, thereby providing a larger upper limit of the head. As a result, the system can provide a larger head and can meet the use requirements of low head and large flow.

[0024] The present invention will become more apparent from the following description taken in conjunction with the accompanying drawings, which are used to illustrate embodiments of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0026] Figure 1 It is a front view of the centrifugal pump of the present invention;

[0027] Figure 2 It is a front view of the volute of the present invention;

[0028] Figure 3 It is a front view of the closed impeller of the present invention;

[0029] Figure 4 It is a rear view of the closed impeller of the present invention;

[0030] Figure 5 is a cross-sectional view of a closed impeller of the present invention;

[0031] Figure 6 is a three-dimensional diagram of a closed impeller of the present invention;

[0032] Figure 7 It is a structural schematic diagram of the centrifugal pump system of the present invention.

[0033] Among them: 1-volute; 11-volute water inlet; 12-volute water outlet pipe; 2-closed impeller; 21-long blades; 22-short blades; 23-impeller water inlet; 24-impeller water outlet channel; 25-motor shaft mounting port; 3-drive motor; 4-water inlet pipe; 41-water inlet branch pipe; 5-main switch valve; 51-water inlet branch switch valve; 6-water outlet pipe; 61-water outlet branch pipe; 7-three-way control valve; 71-connecting branch pipe; 8-first centrifugal pump; 9-second centrifugal pump. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0035] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; of course, it can also be a mechanical connection or an electrical connection; in addition, it can also be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0036] Embodiments of the present invention will now be described with reference to the accompanying drawings.

[0037] Example

[0038] The specific embodiments of the present invention are as follows Figure 1-6 As shown, a centrifugal pump capable of full head use includes a volute 1, a closed impeller 2 and a drive motor 3. Among them, a volute water outlet pipe 12 and a volute water inlet 11 are provided on the volute 1; an impeller water inlet 23 is provided on the closed impeller 2, and a motor shaft mounting port 25 is coaxially provided inside the impeller water inlet 23. In this embodiment, the volute water outlet pipe 12 is tangentially arranged on the edge of the volute 1 along the outer edge of the volute 1, and the volute water inlet 11 is arranged at the axis center of one side wall of the volute 1. The closed impeller 2 is coaxially arranged with the volute 1 and rotatably installed inside the volute 1. At the same time, the impeller water inlet 23 is arranged at the axis center of the side wall of the closed impeller 2 close to the volute water inlet 11. In order to realize the axial rotation of the closed impeller 2 driven by the drive motor 3, the drive motor 3 is arranged on one side of the volute 1, and the output shaft of the drive motor 3 passes through the side wall of the volute 1 and is fixedly connected to the motor shaft mounting port 25.

[0039] In order to achieve the full head use of the centrifugal pump, the closed impeller 2 is provided with six long blades 21 and six short blades 22 which are rotationally symmetrically arranged around its axis. Specifically: the long blades 21 and the short blades 22 are arranged equidistantly and staggered, and both the long blades 21 and the short blades 22 are extended in an arc direction from the edge of the closed impeller 2 to its axis. Compared with the existing centrifugal pumps, the centrifugal pump in this scheme adopts a structure in which six long blades 21 and six short blades 22 are arranged equidistantly and staggered, and both the long blades 21 and the short blades 22 are extended in an arc direction from the edge of the closed impeller 2 to its axis. By superimposing the pressure of the six long blades 21 and the six short blades 22, the head range of the centrifugal pump can be effectively improved, so that it can meet both high-head and low-head operating conditions at the same time, and the efficiency is high.

[0040] In this embodiment, the inner diameter of the volute 1 is 174mm, the diameter of the volute water inlet 11 is 52mm, the length of the volute water outlet pipe 12 is 90mm, and the diameter of the inlet end of the volute water outlet pipe 12 is 25mm, and the diameter of the outlet end is 40mm. Corresponding to the size parameters of the volute 1, the diameter of the closed impeller 2 is 173mm, the diameter of the impeller water inlet 23 is 51mm, the adjacent long blades 21 and short blades 22 form an impeller water outlet channel 24 with a width of 7mm and connected to the inner cavity of the volute 1, and the diameter of the motor shaft mounting port 25 is 10mm. By designing the parameters of the centrifugal pump in this scheme, excessive flow suction can be effectively avoided, thereby reducing power consumption, and thus the power consumed by the centrifugal pump is kept within the effective range of the motor during the entire full-stroke stage.

[0041] It should be noted that, in actual use, in order to further improve the wide range of operating conditions of the product, more than two stages of closed impellers 2 can be equipped in the volute 1 to adapt to applications with higher lift.

[0042] like Figure 7 As shown, the present embodiment also discloses a centrifugal pump system using the above-mentioned centrifugal pump, including a first centrifugal pump 8 and a second centrifugal pump 9 which are coaxially arranged and connected to each other. Among them, the volute water inlets 11 of the first centrifugal pump 8 and the second centrifugal pump 9 are respectively located on the opposite sides of the first centrifugal pump 8 and the second centrifugal pump 9. In addition, the closed impellers 2 of the first centrifugal pump 8 and the second centrifugal pump 9 are arranged in reverse, that is, of the two closed impellers 2 of the first centrifugal pump 8 and the second centrifugal pump 9, one is a positive impeller and the other is a negative impeller. The combination of positive and negative impellers solves the balance of axial force, can offset the axial force, make the structure simpler and more reliable, avoid excessive wear of the motor shaft, and evenly apply radial force on both sides of the motor shaft, so that the operation is stable and the life of the water pump is greatly improved.

[0043] In the centrifugal pump system, the connection relationship between the first centrifugal pump 8 and the second centrifugal pump 9 is as follows: the volute water inlet 11 of the first centrifugal pump 8 is connected to the water inlet pipe 4, and the volute water inlet 11 of the second centrifugal pump 9 is connected to the water inlet pipe 4 through the water inlet branch pipe 41, and the water inlet branch pipe switch valve 51 is installed on the water inlet branch pipe 41. The volute water outlet pipe 12 of the first centrifugal pump 8 is connected to the water outlet pipe 6, and the water outlet pipe 6 is provided with a three-way control valve 7. The three-way control valve 7 is also connected to the volute water inlet 11 of the second centrifugal pump 9 through the connecting branch pipe 71, and the water outlet pipe 6 on the output side of the three-way control valve 7 is connected to the volute water outlet pipe 12 of the second centrifugal pump 9 through the water outlet branch pipe 61.

[0044] In the centrifugal pump system, the series / parallel switching of the first centrifugal pump 8 and the second centrifugal pump 9 can be realized by opening / closing the water inlet branch switch valve 51 and switching the three-way control valve 7. Specifically, when the system is used in the low head stage, the water inlet branch switch valve 51 is opened, the three-way control valve 7 keeps the outlet pipe 6 on the inlet and outlet sides connected, and the connecting branch 71 is closed. At this time, the first centrifugal pump 8 and the second centrifugal pump 9 in the whole system are in parallel state, the flow rate reaches the sum of the two pumps, and the motor power remains unchanged. When the system is used in the high head stage, the water inlet branch switch valve 51 is closed, the three-way control valve 7 blocks the outlet pipe 6 on the inlet and outlet sides, and opens the connecting branch 71. At this time, the first centrifugal pump 8 and the second centrifugal pump 9 in the whole system are in series state, and the head can reach the sum of the first centrifugal pump 8 and the second centrifugal pump 9, so as to provide a larger upper limit of the head. As a result, the system can provide a larger head and can meet the use requirements of low head and large flow.

[0045] In this system, there is only one drive motor 3. The drive motor 3 is arranged on the side of the first centrifugal pump 8 away from the second centrifugal pump 9, and the output shaft of the drive motor 3 passes through the first centrifugal pump 8 and extends into the second centrifugal pump 9. The closed impellers 2 in the first centrifugal pump 8 and the second centrifugal pump 9 are fixedly connected to the output shaft of the drive motor 3 through the motor shaft mounting port 25. In this embodiment, the volute water inlet 11 of the first centrifugal pump 8 and the second centrifugal pump 9 are both provided with mounting pipes, and the first centrifugal pump 8 and the second centrifugal pump 9 are respectively connected to the water inlet pipe 4 and the water inlet branch pipe 41 through the mounting pipes. In addition, the drive motor 3 arranged on the side of the first centrifugal pump 8 away from the second centrifugal pump 9 is also mounted on the mounting pipe of the first centrifugal pump 8. Specifically: the output end of the drive motor 3 is sealed and connected to the end of the mounting pipe away from the first centrifugal pump 8, and the output shaft of the drive motor 3 passes through the first centrifugal pump 8 along the axial direction of the mounting pipe and extends into the second centrifugal pump 9. Furthermore, when the output shaft passes through the junction of the first centrifugal pump 8 and the second centrifugal pump 9, the output shaft and the junction will maintain a rotational seal, thereby preventing the inner cavity of the first centrifugal pump 8 and the inner cavity of the second centrifugal pump 9 from directly communicating with each other.

[0046] In addition, in order to control the water inlet of the entire system, a main switch valve 5 is provided on the input end of the water inlet pipe 4 , and a water inlet branch pipe 41 is arranged on the water inlet pipe 4 at the output side of the main switch valve 5 .

[0047] For the specific use of the system, a 7.5-kilowatt three-phase motor is taken as an example as the driving motor 3. The diameter of the inlet end of the volute outlet pipe 12 of the first centrifugal pump 8 in the system is 25 mm, the diameter of the outlet end is 40 mm, the length is 90 mm, and the diameter of the volute water inlet 11 is 52 mm; the closed impeller 2 is a reverse flow channel with a diameter of 173 mm, the diameter of the impeller water inlet 23 is 51 mm, the diameter of the motor shaft mounting port 25 is 10 mm, and the width of the outlet flow channel is 7 mm.

[0048] The diameter of the inlet end of the volute outlet pipe 12 of the second centrifugal pump 9 in the system is 25mm, the diameter of the outlet end is 40mm, the length is 90mm, and the diameter of the volute water inlet 11 is 52mm; the closed impeller 2 is a positive flow channel with a diameter of 173mm, the diameter of the impeller water inlet 23 is 51mm, the diameter of the motor shaft mounting port 25 is 10mm, and the outlet flow channel width is 7mm.

[0049] The system of this parameter has been tested, and the test parameters of the low-lift section are: 5 meters 56 cubic meters, current 12.6 amps; 35 meters 50 cubic meters, current 14.6 amps; 40 meters 40 cubic meters, current 13.5 amps. The high-lift section is: 68 meters 25 cubic meters, current 14.3 amps, 78 meters 20 cubic meters, current 12.6 amps.

[0050] The existing centrifugal pump impeller design only considers normal operation within the rated value range, and does not consider the working characteristics within the effective power range of the motor. The centrifugal pump system of this solution combines the low-lift and high-flow characteristics of the horizontal centrifugal pump, and can also show the characteristics of the vertical multi-stage centrifugal pump at high lift, with an optimized full-lift centrifugal impeller. Such a centrifugal pump system will not cause overload of the motor power no matter which working condition it is in.

[0051] The present invention has been described above in conjunction with the best embodiments, but the present invention is not limited to the embodiments disclosed above, but should cover various modifications and equivalent combinations based on the essence of the present invention.

Claims

1. A centrifugal pump capable of full head use, comprising a volute (1), a closed impeller (2) and a drive motor (3), wherein the volute (1) is provided with a volute water outlet pipe (12) and a volute water inlet (11), the closed impeller (2) is provided with an impeller water inlet (23), and a motor shaft mounting port (25) is coaxially provided inside the impeller water inlet (23), characterized in that: The closed impeller (2) is provided with six long blades (21) and six short blades (22) which are arranged rotationally symmetrically around its axis. The long blades (21) and the short blades (22) are arranged in an equidistant and staggered manner, and the long blades (21) and the short blades (22) are both arranged to extend in an arc direction from the edge of the closed impeller (2) toward its axis.

2. The centrifugal pump capable of full head use according to claim 1, characterized in that: The inner diameter of the volute (1) is 174 mm, the diameter of the volute water inlet (11) is 52 mm, the length of the volute water outlet pipe (12) is 90 mm, the diameter of its inlet end is 25 mm, and the diameter of its outlet end is 40 mm.

3. The centrifugal pump capable of full head use according to claim 2, characterized in that: The diameter of the closed impeller (2) is 173 mm, the diameter of the impeller water inlet (23) is 51 mm, the adjacent long blades (21) and short blades (22) form an impeller water outlet channel (24) with a width of 7 mm and connected to the inner cavity of the volute (1), and the diameter of the motor shaft mounting port (25) is 10 mm.

4. The centrifugal pump capable of full head use according to claim 3, characterized in that: The volute water outlet pipe (12) is tangentially arranged on the edge of the volute (1) along the outer edge of the volute (1); the volute water inlet (11) is arranged at the axis center of a side wall of the volute (1); and the closed impeller (2) is coaxially arranged with the volute (1) and rotatably installed inside the volute (1).

5. The centrifugal pump capable of full head use according to claim 4, characterized in that: The impeller water inlet (23) is arranged at the axis center of the side wall of the closed impeller (2) close to the volute water inlet (11).

6. The centrifugal pump capable of full head use according to claim 5, characterized in that: The drive motor (3) is arranged on one side of the volute (1), and the output shaft of the drive motor (3) passes through the side wall of the volute (1) and is fixedly connected to the motor shaft mounting opening (25).

7. A centrifugal pump system using the centrifugal pump according to any one of claims 1 to 6, characterized in that: The invention comprises a first centrifugal pump (8) and a second centrifugal pump (9) which are coaxially arranged and connected to each other, wherein the volute water inlets (11) of the first centrifugal pump (8) and the second centrifugal pump (9) are respectively located on opposite sides of the first centrifugal pump (8) and the second centrifugal pump (9), and the closed impellers (2) of the first centrifugal pump (8) and the second centrifugal pump (9) are arranged in opposite directions; The volute water inlet (11) of the first centrifugal pump (8) is connected to a water inlet pipe (4), and the volute water inlet (11) of the second centrifugal pump (9) is communicated with the water inlet pipe (4) through a water inlet branch pipe (41), and a water inlet branch pipe switch valve (51) is installed on the water inlet branch pipe (41); the volute water outlet pipe (12) of the first centrifugal pump (8) is connected to a water outlet pipe (6), and a three-way control valve (7) is provided on the water outlet pipe (6), and the three-way control valve (7) is also communicated with the volute water inlet (11) of the second centrifugal pump (9) through a connecting branch pipe (71), and the water outlet pipe (6) on the output side of the three-way control valve (7) is communicated with the volute water outlet pipe (12) of the second centrifugal pump (9) through a water outlet branch pipe (61).

8. The centrifugal pump system according to claim 7, characterized in that There is only one driving motor (3).

9. The centrifugal pump system according to claim 8, characterized in that The drive motor (3) is arranged on a side of the first centrifugal pump (8) away from the second centrifugal pump (9), and the output shaft of the drive motor (3) passes through the first centrifugal pump (8) and extends into the second centrifugal pump (9), and the closed impellers (2) in the first centrifugal pump (8) and the second centrifugal pump (9) are fixedly connected to the output shaft of the drive motor (3) through the motor shaft mounting opening (25).

10. The centrifugal pump system according to claim 1, characterized in that A main switch valve (5) is provided on the input end of the water inlet pipe (4), and the water inlet branch pipe (41) is arranged on the water inlet pipe (4) on the output side of the main switch valve (5).

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