Self-priming pump and drainage operation equipment

Abstract

This disclosure relates to a self-priming pump and drainage equipment. The self-priming pump includes: a primary pump unit comprising a primary volute, a primary impeller, and a primary outlet pipe, wherein the primary volute has a first inlet, the primary impeller is disposed within the primary volute, and the primary outlet pipe is connected to the primary volute; a secondary pump unit comprising a secondary volute, a secondary impeller, a secondary outlet pipe, and a suction chamber, wherein the secondary impeller is disposed within the secondary volute, and both the secondary outlet pipe and the suction chamber are connected to the secondary volute; and a switching valve comprising a valve housing and a valve core, wherein the valve housing has a second inlet, the valve core is disposed within the valve housing, and the valve housing is connected to both the suction chamber and the primary volute; wherein the switching valve is configured to, when the valve core is in the first position, close the second inlet by means of the valve core and connect the suction chamber to the primary volute via the valve housing, and when the valve core is in the second position, close the connection between the valve housing and the primary volute by means of the valve core and connect the suction chamber to the second inlet via the valve housing.

Description

Technical Field

[0001] This disclosure relates to a self-priming pump and drainage equipment. Background Technology

[0002] In recent years, extreme weather events have become more frequent, and urban flood-prone areas such as underground parking lots, underground shopping malls, subway stations, tunnels, culverts, and underpasses are prone to flooding and waterlogging disasters. The water volume at disaster sites is enormous, and the vertical height differences are also significant.

[0003] For locations with a low difference in elevation between the flooded area and the ground, such as underground parking garages with 1-2 underground levels, the technology employs drainage robots with a large flow rate to quickly drain the water. However, these robots lack sufficient lift when operating in locations with a high difference in elevation between the flooded area and the ground. For locations with a high difference in elevation between the flooded area and the ground, such as underground parking garages with 4-5 underground levels and subway stations, the technology employs drainage robots with a large lift to smoothly drain the water from the underground space. However, these robots have limited flow rate and longer drainage times when operating in locations with a low difference in elevation between the flooded area and the ground. Summary of the Invention

[0004] In view of this, the present disclosure provides a self-priming pump and drainage operation equipment, which can improve the adaptability of drainage operation scenarios.

[0005] In one aspect of this disclosure, a self-priming pump is provided, comprising:

[0006] The first-stage pump unit includes a first-stage volute, a first-stage impeller, and a first-stage outlet pipe. The first-stage volute has a first inlet, the first-stage impeller is disposed inside the first-stage volute, and the first-stage outlet pipe is connected to the first-stage volute.

[0007] The secondary pump unit includes a secondary volute, a secondary impeller, a secondary outlet pipe, and a suction chamber. The secondary impeller is disposed within the secondary volute, and both the secondary outlet pipe and the suction chamber are connected to the secondary volute.

[0008] A switching valve includes a valve housing and a valve core. The valve housing has a second liquid inlet, and the valve core is disposed inside the valve housing. The valve housing is in communication with both the liquid suction chamber and the first-stage volute.

[0009] The switching valve is configured to, when the valve core is in the first position, close the second inlet through the valve core and connect the suction chamber and the first-stage volute via the valve housing; and when the valve core is in the second position, close the communication channel between the valve housing and the first-stage volute through the valve core and connect the suction chamber and the second inlet via the valve housing.

[0010] In some embodiments, the suction chamber includes a first segment located on the side of the secondary volute away from the primary volute. The inner wall of the first segment includes a first arcuate surface and a second arcuate surface. The first arcuate surface and the second arcuate surface intersect on the side of the secondary impeller's rotation axis away from the valve housing, and the distance from the intersection point to the rotation axis of the secondary impeller is less than the distance from other points on the first arcuate surface and the second arcuate surface to the rotation axis of the secondary impeller.

[0011] In some embodiments, the first arcuate surface and the second arcuate surface are symmetrically arranged with respect to a first reference plane, the first reference plane passing through the intersection point and the rotation axis of the secondary impeller.

[0012] In some embodiments, the angle between the inner normal of the first arcuate surface at the intersection position and the inner normal of the second arcuate surface at the intersection position is 20° to 50°.

[0013] In some embodiments, the first segment further includes a retractable liquid inlet connected to the secondary volute.

[0014] In some embodiments, at least a portion of the spatial center line of the suction chamber from the position where the suction chamber connects to the secondary volute to the position where the suction chamber connects to the valve housing is a three-dimensional spiral.

[0015] In some embodiments, the suction chamber includes a second section connected to and internally communicating with the valve housing, and the secondary outlet pipe and the portion of the second section located on the upper side of the secondary volute are respectively located on both sides of a second reference plane, which is a vertical plane passing through the rotation axis of the secondary impeller.

[0016] In some embodiments, in the direction from the position where the suction chamber connects to the valve housing to the position where the suction chamber connects to the secondary volute, the width of the second segment in a cross section perpendicular to the rotation axis of the secondary impeller gradually increases.

[0017] In some embodiments, the self-priming pump further includes:

[0018] A vacuum extraction device is configured to extract air from at least one of the primary volute and the secondary volute.

[0019] In some embodiments, the vacuum extraction device includes:

[0020] Vacuum priming tank with an interface for connecting to an external vacuum pump;

[0021] A three-way connector has three ends: the first end connects to the first liquid inlet via a gas guide tube; the second end connects to the liquid suction chamber via a pipe; and the third end connects to the vacuum liquid priming box via a pipe.

[0022] A hydraulic control valve, located on the three-way connector or between the three-way connector and the suction chamber, is configured to control the connection or disconnection between the air guide tube and the suction chamber.

[0023] In some embodiments, the vacuum liquid collection box is fixedly disposed on the outer wall of the suction chamber on the side away from the switching valve.

[0024] In some embodiments, the switching valve is a rotary spool valve, and the valve core is rotatable within the valve housing between the first position and the second position.

[0025] In some embodiments, the valve housing includes a hollow cylindrical section, a first outer pipe section, and a second outer pipe section. The hollow cylindrical section has a first connection port for communicating with the first-stage volute. The first outer pipe section and the second outer pipe section are connected to both sides of the hollow cylindrical section. One end of the first outer pipe section is connected to the hollow cylindrical section, and the other end serves as the second liquid inlet. One end of the second outer pipe section is connected to the hollow cylindrical section, and the other end is connected to the suction chamber through the second connection port.

[0026] In some embodiments, the valve core has an arc-shaped internal channel configured to communicate with the second outer pipe section and the first connection port when the valve core is in a first position, and to smoothly transition with the inner walls of the second outer pipe section and the connection port; and to communicate with the first outer pipe section and the second outer pipe section when the valve core is in a second position, and to smoothly transition with the inner walls of the first outer pipe section and the second outer pipe section.

[0027] In some embodiments, on a plane perpendicular to the axis of the valve core, the lines connecting the axis of the valve core to the first center of the connection port of the hollow cylindrical section, the second center of the position connected to the first outer pipe section, and the third center of the position connected to the second outer pipe section are arranged circumferentially at 120°.

[0028] In some embodiments, the switching valve further includes:

[0029] An end plate, disposed on the outside of the valve housing, is fixedly connected to the valve core and rotates relative to the valve housing together with the valve core; and

[0030] A switching cylinder is connected to the end plate at a position offset from the axis of rotation of the valve core, and is configured to drive the end plate to rotate so as to switch the position of the valve core.

[0031] In some embodiments, the self-priming pump further includes:

[0032] A flapping device is disposed at the end of at least one of the primary liquid outlet pipe and the secondary liquid outlet pipe, for controlling the liquid discharge of at least one of the primary liquid outlet pipe and the secondary liquid outlet pipe.

[0033] In some embodiments, the flapping device includes a double-section flapping gate.

[0034] In some embodiments, the self-priming pump further includes:

[0035] The drive shaft passes through the first-stage volute and the second-stage volute, and is drively connected to both the first-stage impeller and the second-stage impeller; and

[0036] A bearing support structure is connected to the drive shaft and configured to provide bearing support for the drive shaft.

[0037] In one aspect of this disclosure, a drainage operation device is provided, comprising: the aforementioned self-priming pump.

[0038] In some embodiments, the self-priming pump includes a vacuum priming tank and a drive shaft. The drive shaft passes through the first-stage volute and the second-stage volute and is drively connected to both the first-stage impeller and the second-stage impeller. The drainage equipment further includes a tracked chassis, an engine, a vacuum pump, and a clutch. The engine, the vacuum pump, and the self-priming pump are all mounted on the tracked chassis. The engine is connected to the drive shaft via the clutch, and the vacuum pump is connected to the interface of the vacuum priming tank.

[0039] Therefore, according to the embodiments of this disclosure, by switching the valve core of the switching valve at different positions, the communication relationship between the suction chamber and the secondary volute and between the primary volute and the second inlet is changed, thereby forming a series or parallel relationship between the primary volute and the secondary volute, thereby meeting the drainage requirements under different head and flow rates and improving the scenario adaptability of drainage operations. Attached Figure Description

[0040] The accompanying drawings, which form part of this specification, illustrate embodiments of this disclosure and, together with the specification, serve to explain the principles of this disclosure.

[0041] This disclosure will become clearer with reference to the accompanying drawings and the following detailed description, wherein:

[0042] Figure 1 This is a schematic diagram of the installation structure of some embodiments of the self-priming pump disclosed herein;

[0043] Figure 2 This is a schematic diagram of the switching valve in an embodiment of the self-priming pump disclosed herein;

[0044] Figure 3 These are cross-sectional schematic diagrams of some embodiments of the self-priming pump disclosed herein;

[0045] Figure 4 This is a schematic diagram of the installation structure of the self-priming pump embodiment of the present disclosure with the switching cylinder in the extended state;

[0046] Figure 5 and Figure 6 These are schematic diagrams of the internal cross-sections of the valve core in the second position P2 and the first position P1 in the self-priming pump embodiment of this disclosure.

[0047] Figure 7 This is a schematic diagram of the installation structure of the self-priming pump embodiment of the present disclosure with the switching cylinder in the retracted state;

[0048] Figure 8 This is a schematic diagram of the installation structure of some embodiments of the self-priming pump disclosed herein from another perspective;

[0049] Figure 9 This is a partial schematic diagram of the installation structure of the vacuum extraction device in an embodiment of the self-priming pump disclosed herein;

[0050] Figure 10 This is a schematic diagram of the structure of the first-stage pump body unit excluding the first-stage impeller in an embodiment of the self-priming pump disclosed herein;

[0051] Figure 11 This is a schematic diagram of the secondary pump body unit excluding the secondary impeller in an embodiment of the self-priming pump disclosed herein;

[0052] Figure 12 yes Figure 11 A structural diagram from another perspective;

[0053] Figure 13 yes Figure 11 A schematic diagram of the structure from a view perpendicular to the rotation axis of the secondary impeller;

[0054] Figure 14 yes Figure 13 AA section diagram;

[0055] Figure 15 This is a schematic cross-sectional view of the suction chamber in an embodiment of the self-priming pump disclosed herein;

[0056] Figure 16 yes Figure 15 A schematic diagram of various configurations of the first and second arc-shaped surfaces;

[0057] Figure 17 yes Figure 11 A schematic diagram of the structure from a view parallel to the rotation axis of the secondary impeller;

[0058] Figure 18 yes Figure 17 Schematic diagram of the BB cross section;

[0059] Figure 19 This is a schematic diagram of the flap valve device in an embodiment of the self-priming pump disclosed herein;

[0060] Figure 20 These are schematic diagrams illustrating the installation structure of some embodiments of the drainage operation equipment disclosed herein;

[0061] Figure 21 This is a schematic diagram of the control principle of an embodiment of the drainage operation equipment disclosed herein;

[0062] Figure 22 This is a schematic diagram of the operation process of an embodiment of the drainage operation equipment disclosed herein.

[0063] It should be understood that the dimensions of the various parts shown in the accompanying drawings are not drawn to actual scale. Furthermore, the same or similar reference numerals denote the same or similar components.

[0064] Explanation of reference numerals in the attached figures

[0065] 10-First stage pump body unit; 11-First stage volute; 12-First stage impeller; 13-First stage outlet pipe;

[0066] 20 - Secondary pump body unit; 21 - Secondary volute; 22 - Secondary impeller; 22a - Rotation axis of secondary impeller; 23 - Secondary outlet pipe; 24 - Suction chamber; 241 - First section; 241a - Contracting inlet; 242 - Second section; 243 - Spatial center line; 25 - Bend;

[0067] 30-Switching valve; 31-Valve housing; 311-Hollow cylindrical section; 311a-First connection port; 312-First external pipe section; 313-Second external pipe section; 313a-Second connection port; 32-Valve core; 321-Arc-shaped internal channel; 32a-Axis of valve core; 33-End plate; 34-Switching cylinder;

[0068] 40-Vacuum extraction device; 41-Vacuum liquid priming tank; 42-T-connector; 43-Gas delivery pipe; 44-Hydraulic control valve; 45-Conical connector; 46-Mounting base;

[0069] 51, 52 - Flap valve device; 5a - Upper valve section; 5b - Lower valve section; 5c - Flap valve housing; 5d - Hydraulic control plug;

[0070] 61-Drive shaft;

[0071] 71-Self-priming pump; 72-Crawler chassis; 73-Engine; 74-Vacuum pump; 75-Clutch; 76-Electro-hydraulic valve; 77-Hydraulic pump; 78-Controller;

[0072] a1-Shaft sleeve nut; a2-First skeleton oil seal; a3-First bearing housing; a4-Bearing sealing gland; a5-Second bearing housing; a6-Sealing ring; a7-Rubber cap; a8-Impeller nut; a9-First flat key; a10-First mechanical seal shaft sleeve; a11-First mechanical seal; a12-Second flat key; a13-Second skeleton oil seal; a14-Inner sealing plate; a15-First bearing; a16-Plug; a17-Intermediate retaining sleeve; a18-Third flat key; a19-Mechanical seal retaining ring; a20-Set screw; a21-Second mechanical seal; a22-Third skeleton oil seal; a23-Bearing retaining ring; a24-Third bearing housing; a25-Fourth flat key; a26-Secondary mechanical seal shaft sleeve; a27-Second bearing;

[0073] IN1 - First inlet; IN2 - Second inlet; P1 - First position; P2 - Second position; ARC1 - First arc surface; ARC2 - Second arc surface; CP - Intersection position; RP1 - First reference plane; RP2 - Second reference plane; RP3 - Third reference plane; C1 - First center; C2 - Second center; C3 - Third center. Detailed Implementation

[0074] Various exemplary embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings. The descriptions of the exemplary embodiments are merely illustrative and are in no way intended to limit the present disclosure or its application or use. The present disclosure may be implemented in many different forms and is not limited to the embodiments described herein. These embodiments are provided so that the present disclosure will be thorough and complete, and will fully express the scope of the disclosure to those skilled in the art. It should be noted that, unless specifically stated otherwise, the relative arrangement of components and steps, the composition of materials, numerical expressions, and values ​​set forth in these embodiments should be interpreted as exemplary only and not as limiting.

[0075] The terms "first," "second," and similar words used in this disclosure do not indicate any order, quantity, or importance, but are merely used to distinguish different parts. Words such as "including" or "contains" mean that the element preceding the word encompasses the element listed after it, and do not exclude the possibility of encompassing other elements as well. Terms such as "above," "below," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, this relative positional relationship may also change accordingly.

[0076] In this disclosure, when a specific device is described as being located between a first device and a second device, an intermediary device may or may not be present between the specific device and the first or second device. When a specific device is described as being connected to other devices, the specific device may be directly connected to the other devices without an intermediary device, or it may be not directly connected to the other devices but have an intermediary device.

[0077] All terms used in this disclosure (including technical or scientific terms) have the same meaning as understood by one of ordinary skill in the art to which this disclosure pertains, unless otherwise specifically defined. It should also be understood that terms defined in a general dictionary, such as a dictionary, should be interpreted as having a meaning consistent with their meaning in the context of the relevant art, and not as having an idealized or highly formalized meaning, unless expressly defined herein.

[0078] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and equipment should be considered part of the specification.

[0079] Figure 1 This is a schematic diagram of the installation structure of some embodiments of the self-priming pump disclosed herein. (Reference) Figure 1 as well as Figures 2-19 This disclosure provides a self-priming pump for drainage operations. Drainage can refer to discharging liquid substances, such as water or suspensions. For example, drainage operations can be flood control operations that pump water that is at a height difference from the ground upwards. In other embodiments, the self-priming pump can be used to drain other types of liquids or suspensions.

[0080] In this embodiment, the self-priming pump 71 includes: a primary pump unit 10, a secondary pump unit 20, and a switching valve 30. The primary and secondary pump units can be determined according to the flow sequence of the liquid when the self-priming pump 71 is in series operation.

[0081] The primary pump unit 10 includes a primary volute 11, a primary impeller 12, and a primary outlet pipe 13. The primary volute 11 has a first inlet IN1, the primary impeller 12 is disposed inside the primary volute 11, and the primary outlet pipe 13 is connected to the primary volute 11.

[0082] The secondary pump unit 20 includes a secondary volute 21, a secondary impeller 22, a secondary outlet pipe 23, and a suction chamber 24. The secondary impeller 22 is disposed inside the secondary volute 21, and the secondary outlet pipe 23 and the suction chamber 24 are both connected to the secondary volute 21.

[0083] The switching valve 30 includes a valve housing 31 and a valve core 32. The valve housing 31 has a second liquid inlet IN2, and the valve core 32 is disposed inside the valve housing 31. The valve housing 31 is in communication with both the liquid suction chamber 24 and the first-stage volute 11. The valve core 32 can have multiple working positions within the valve housing 31 to meet switching requirements.

[0084] The switching valve 30 can, when the valve core 32 is in the first position P1, close the second liquid inlet IN2 through the valve core 32 and make the liquid suction chamber 24 and the first-stage volute 11 connected through the valve housing 31; and when the valve core 32 is in the second position P2, close the communication channel between the valve housing 31 and the first-stage volute 11 through the valve core 32 and make the liquid suction chamber 24 and the second liquid inlet IN2 connected through the valve housing 31.

[0085] refer to Figure 1 and Figure 6 When the self-priming pump 71 needs to operate in series, the valve core 32 can be switched to the first position P1. At this time, the valve core 32 closes the second inlet IN2, and the suction chamber 24 is connected to the first-stage volute 11. The switching valve 30 then connects the first-stage volute 11 and the secondary volute 21 in series. The liquid flows into the first-stage volute 11 from the first inlet IN1, and under the drive of the first-stage impeller 12, flows from the first-stage volute 11 to the switching valve 30, and then through the valve housing 31 of the switching valve 30 to the suction chamber 24. From the suction chamber 24, it flows into the secondary volute 21, and under the drive of the secondary impeller 22, it flows out through the secondary outlet pipe 23. In series operation, the driving action of the two-stage impeller can meet the drainage needs of larger head and smaller flow rate, such as for flood drainage operations in places where the water surface is significantly different from the ground level.

[0086] refer to Figure 1 and Figure 5 When the self-priming pump 71 needs to operate in parallel mode, the valve core 32 can be switched to the second position P2. At this time, the valve housing 31 is connected to the first-stage volute 11, and the suction chamber 24 is connected to the second inlet IN2. Thus, the first-stage volute 11 is connected to the suction chamber 24 via the valve body. At this time, the switching valve 30 makes the first-stage volute 11 and the secondary volute 21 form a parallel relationship. The liquid flow entering from the first inlet IN1 flows into the first-stage volute 11 and flows to the first-stage outlet pipe 13 under the drive of the first-stage impeller 12. The liquid flow entering from the second inlet IN2 flows to the suction chamber 24 via the valve housing 31 of the switching valve 30, and then flows into the secondary volute 21 from the suction chamber 24. Under the drive of the secondary impeller 22, it flows outward from the secondary outlet pipe 23. In parallel operation, the primary impeller and the secondary impeller drive the two parallel liquid flows respectively, which can meet the drainage needs of smaller head and larger flow rate, such as realizing flood drainage operations in places where the height difference between the water surface and the ground is small.

[0087] In this way, by using the switching function of the switching valve 30, the self-priming pump 71 can have two operating modes: a larger head and a smaller flow rate, and a smaller head and a larger flow rate, thereby meeting the usage needs in different scenarios and improving the scenario adaptability of the drainage operation.

[0088] refer to Figure 2 , Figure 5 and Figure 6 In some embodiments, the switching valve 30 is a rotary slide valve, and the valve core 32 is rotatable within the valve housing 31 between the first position P1 and the second position P2. This structure is more compact in space, facilitates switching control, and is less prone to fluid leakage.

[0089] refer to Figure 5 In some embodiments, for a rotary slide valve, the valve body 31 includes a hollow cylindrical section 311, a first outer connecting pipe section 312, and a second outer connecting pipe section 313. The first outer connecting pipe section 312 and the second outer connecting pipe section 313 are connected to both sides of the hollow cylindrical section 311. Here, the first outer connecting pipe section 312 and the second outer connecting pipe section 313 can be welded to or connected to both sides of the hollow cylindrical section 311 by connectors, or they can be integrally formed with the hollow cylindrical section 311.

[0090] refer to Figure 2 and Figure 4 The hollow cylindrical section 311 has a first connection port 311a for connecting to the first-stage volute 11. One end of the first outer pipe section 312 is connected to the hollow cylindrical section 311, and the other end serves as the second liquid inlet IN2. One end of the second outer pipe section 313 is connected to the hollow cylindrical section 311, and the other end is connected to the suction chamber 24 through the second connection port 313a.

[0091] The valve housing 31 can be located on the upper side of the primary volute 11 and the secondary volute 21, and the center lines of the first connection port 311a, the second inlet port IN2, and the second connection port 313a can each be located on the same plane. This plane can be perpendicular to the axis 32a of the valve core 32 and parallel to the mounting plane of the self-priming pump 71, which makes the structure more compact and occupies less space.

[0092] refer to Figure 5 and Figure 6 In some embodiments, the valve core 32 has an arc-shaped internal channel 321. Here, the arc-shaped internal channel 321 means that the outline of the cross-section of the inner wall of the internal channel of the valve core 32 along the axis 32a of the valve core 32 includes an arc. For example, in... Figure 5 In the middle, the valve core 32 is cylindrical, and the arc-shaped internal channel 321 runs from one side of the valve core 32 to the other side of the valve core 32. The inner walls on both sides of the arc-shaped internal channel 321 are cylindrical surfaces with concave arc curves and cylindrical surfaces with convex arc curves, respectively.

[0093] exist Figure 6In the process, the arc-shaped internal channel 321 communicates with the second outer pipe section 313 and the first connection port 311a when the valve core 32 is in the first position P1, and smoothly transitions with the inner walls of the second outer pipe section 313 and the connection port 311a. Figure 5 In the process, the arc-shaped internal channel 321 communicates with the first outer pipe section 312 and the second outer pipe section 313 when the valve core 32 is in the second position P2, and smoothly transitions with the inner walls of the first outer pipe section 312 and the second outer pipe section 313.

[0094] Since the arc-shaped internal channel 321 can smoothly transition to the inner wall of the structure it connects at both the first position P1 and the second position P2, the liquid flow can pass through the switching valve 30 more smoothly, reducing pressure and flow rate losses and improving overall performance.

[0095] refer to Figure 6 In some embodiments, on a plane perpendicular to the axis 32a of the valve core 32, the lines connecting the axis 32a of the valve core 32 to the first center C1 of the connection port of the hollow cylindrical section 311, the second center C2 of the position connecting to the first outer pipe section 312, and the third center C3 of the position connecting to the second outer pipe section 313 are arranged circumferentially at 120°. This arrangement ensures that the valve core 32 can accurately switch between the first position P1 and the second position P2 by rotating 120° in a preset direction, achieving a more compact and lighter spool valve structure. This switching valve 30 is simpler to manufacture and helps to improve production efficiency. In other embodiments, the switching valve 30 can also adopt a ball valve structure.

[0096] refer to Figure 1 , Figure 2 , Figure 4 and Figure 7 In some embodiments, the switching valve 30 further includes an end plate 33 and a switching cylinder 34. The end plate 33 is disposed outside the valve housing 31, fixedly connected to the valve core 32, and rotates together with the valve core 32 relative to the valve housing 31. The switching cylinder 34 is connected to the end plate 33 at a position offset from the axis 32a that rotates the valve core 32, and is configured to drive the end plate 33 to rotate, thereby causing the valve core 32 to switch positions.

[0097] By placing the end plate 33, which drives the valve core 32 to rotate, and the switching cylinder 34 on the outside of the valve housing 31, compared to placing the relevant drive structure inside the valve housing 31, it is advantageous to reduce the size of the valve housing 31 and to facilitate the installation of a switching cylinder 34 capable of achieving a larger torque. This allows the valve core 32 to be reliably rotated by applying torque to the end plate 33 from outside the valve housing 31. The switching cylinder 34 uses working oil supplied by the hydraulic system to extend and retract the piston rod.

[0098] In other embodiments, the switching valve 30 may also be switched in other ways, such as by switching the working position of the valve core of the switching valve 30 by electronic control.

[0099] refer to Figure 1 , Figure 3 , Figure 7 and Figure 8 In some embodiments, the self-priming pump 71 further includes a flap valve device disposed at the end of at least one of the primary outlet pipe 13 and the secondary outlet pipe 23, for controlling the discharge of at least one of the primary outlet pipe 13 and the secondary outlet pipe 23.

[0100] exist Figure 4 and Figure 7 In this configuration, a flap valve 51 is installed at the end of the primary outlet pipe 13. By closing the flap valve 51, in conjunction with the series operation of the self-priming pump 71, the liquid flow enters the primary volute 11 from the first inlet IN1, and flows from the primary volute 11 to the switching valve 30 under the drive of the primary impeller 12, instead of being discharged outward from the primary outlet pipe 13. Furthermore, the liquid flow passes through the valve housing 31 of the switching valve 30 to the suction chamber 24, and then flows from the suction chamber 24 into the secondary volute 21, where it flows outward from the secondary outlet pipe 23 under the drive of the secondary impeller 22.

[0101] By opening the flap valve 51, the self-priming pump 71 can operate in parallel, allowing the liquid entering from the first inlet IN1 to flow into the first-stage volute 11. Driven by the first-stage impeller 12, the liquid flows from the first-stage volute 11 to the first-stage outlet pipe 13 and is discharged outwards through the flap valve 51. The liquid entering from the second inlet IN2 flows through the valve housing 31 of the switching valve 30 to the suction chamber 24, and then flows from the suction chamber 24 into the secondary volute 21. Driven by the secondary impeller 22, the liquid flows outwards through the secondary outlet pipe 23.

[0102] exist Figure 7 and Figure 8 In this system, a flap valve 52 can be installed at the end of the secondary outlet pipe 23 to open or close the secondary outlet pipe 23. A bend 25 can also be further connected to the flap valve 52 to adjust the direction of the outward discharge of liquid from the secondary outlet pipe 23. For example, the outlet of the bend 25 can be aligned with the outlet direction of the flap valve 51 to facilitate the site or pipeline layout on the drainage side.

[0103] Optionally, the flap valve device includes a double-clap flap valve. (See reference) Figure 19The double-section flap valve may include an upper section valve 5a, a lower section valve 5b, a flap valve housing 5c, and a hydraulic control plug 5d. In parallel operation of the self-priming pump 71, the hydraulic control plug is open. After the self-priming pump 71 starts, the lower section valve 5b opens first due to the impact of the water flow, and the upper section valve 5a opens under the impact of the water flow and the buoyancy of the lower section valve 5b. This reduces the head loss when the hydraulic control plug 5d opens. In series operation of the self-priming pump 71, the hydraulic control plug 5d is closed, and the lower section valve 5b is locked.

[0104] refer to Figure 1 In some embodiments, the self-priming pump 71 further includes a vacuum extraction device 40. The vacuum extraction device 40 is configured to extract air from at least one of the primary volute 11 and the secondary volute 21. By extracting air from at least one of the primary volute 11 and the secondary volute 21, rapid water discharge from the self-priming pump 71 can be achieved. Figure 3 and Figure 10 In the first stage volute 11, the first liquid inlet IN1 can be designed as a straight pipe and a suction port can be set to connect to the vacuum extraction device 40 to meet the vacuum requirements, thereby reducing the overall size.

[0105] refer to Figure 3 , Figure 4 and Figure 9 In some embodiments, the vacuum extraction device 40 includes: a vacuum priming tank 41, a three-way connector 42, and a hydraulic control valve 44. The vacuum priming tank 41 is connected to an external vacuum pump 74 (see reference). Figure 20 The three-way connector 42 has a first end connected to the first liquid inlet IN1 via a gas guide pipe 43, a second end connected to the liquid suction chamber 24 via a pipe, and a third end connected to the vacuum liquid collection box 41 via a pipe. A liquid-controlled switch valve 44 is located on the three-way connector 42 or between the three-way connector 42 and the liquid suction chamber 24, and is configured to control the connection or disconnection between the gas guide pipe 43 and the liquid suction chamber 24.

[0106] In parallel operation of the self-priming pump 71, the hydraulic control valve 44 is open, and the air guide pipe 43 is connected to the liquid suction chamber 24. The vacuum pump 74 quickly extracts air from the first-stage volute 11 and the secondary volute 21 through the vacuum priming tank 41, achieving rapid water output. In series operation of the self-priming pump 71, the hydraulic control valve 44 is closed, and the air guide pipe 43 is disconnected from the liquid suction chamber 24. The vacuum pump 74 quickly extracts air from the first-stage volute 11 through the vacuum priming tank 41, achieving rapid water output, while preventing high-pressure water from the secondary volute 21 from entering the vacuum priming tank 41 and causing damage to the internal structure.

[0107] refer to Figure 4In some embodiments, the vacuum liquid collection box 41 is fixedly disposed on the outer wall of the suction chamber 24 on the side away from the switching valve 30. Figure 4 In this system, a mounting base 46 can be fixedly connected to the outer shell of the suction chamber 24, and the vacuum liquid collection box 41 can be mounted on the mounting base 46 via connectors (e.g., bolts). A tapered connector 45 is provided at the lower end of the mounting base 46 or the lower end of the vacuum liquid collection box 41 for connecting pipelines.

[0108] To analyze the flow losses in this scheme, flow loss analysis can be performed on the structures of the primary and secondary pump units based on entropy production theory. Wall entropy production accounts for the highest proportion, followed by turbulent dissipation entropy production, with direct dissipation entropy production being the smallest. The orders of magnitude of both wall entropy production and turbulent dissipation entropy production are much larger than those of direct dissipation entropy production. Therefore, the contribution of direct dissipation entropy production to pump flow losses can be ignored. Wall entropy production and turbulent kinetic energy entropy production play a dominant role in pump flow losses, and subsequent analysis will focus primarily on wall entropy production and turbulent dissipation entropy production.

[0109] For the wall entropy production and turbulent dissipation entropy production of the primary and secondary pump units under rated operating conditions, the entropy production is mainly concentrated on the working surface of the blades and the inlet and outlet edges of the blades. The presence of entropy production at the blade inlet indicates that the incoming flow impacts the blade inlet, resulting in flow loss. The presence of entropy production at the blade outlet is caused by the dynamic and static interference between the impeller and the volute. Therefore, the flow loss inside the impeller is mainly concentrated in the impeller inlet and outlet regions.

[0110] For the secondary pump unit including the suction chamber, entropy production is mainly concentrated at the suction chamber inlet and the inlet of the suction chamber near the secondary volute. The main reason for entropy production at the suction chamber inlet is that the flow direction of the incoming flow changes at this point, resulting in flow losses. The main reason for entropy production at the inlet of the suction chamber near the secondary volute is that the flow direction changes from radial to axial relative to the rotation axis of the secondary impeller, resulting in flow losses. Therefore, the flow losses are relatively large at these two locations.

[0111] refer to Figures 11-15 In some embodiments, the suction chamber 24 includes a first segment 241 located on the side of the secondary volute 21 away from the primary volute 11. The inner wall of the first segment 241 includes a first arcuate surface ARC1 and a second arcuate surface ARC2.

[0112] exist Figure 14In the process, the first arc-shaped surface ARC1 and the second arc-shaped surface ARC2 intersect on the side of the rotation axis 22a of the secondary impeller 22 away from the valve housing 31, and the distance d1 from the intersection point CP to the rotation axis 22a of the secondary impeller 22 is less than the distances d2 and d3 from other positions on the first arc-shaped surface ARC1 and the second arc-shaped surface ARC2 to the rotation axis 22a of the secondary impeller 22.

[0113] exist Figure 14 and Figure 15 As can be seen, the intersection position CP is closer to the rotation axis 22a of the secondary impeller 22 than other positions on the first arc surface ARC1 and the second arc surface ARC2, forming a structure in which the intersection position CP protrudes toward the rotation axis 22a.

[0114] The portion of the liquid flow entering the suction chamber 24 from the switching valve 30 can flow along the first arc-shaped surface ARC1 and the second arc-shaped surface ARC2 towards the inlet of the second volute 21. According to the streamline diagram obtained from the simulation, vortices appear in the liquid flow near the inlet of the second volute 21, leading to increased inflow losses to the second volute 21 caused by the suction chamber. By making the intersecting position CP bulge towards the rotation axis 22a, the liquid flow can be guided, reducing the vortices near the inlet of the second volute 21, thereby reducing the inflow losses to the second volute 21 caused by the suction chamber and improving overall performance.

[0115] refer to Figure 15 In some embodiments, the first arcuate surface ARC1 and the second arcuate surface ARC2 are symmetrically arranged with respect to the first reference plane RP1, which passes through the intersection point CP and the rotation axis 22a of the secondary impeller 22. A portion of the liquid flow entering the suction chamber 24 can flow from both sides of the first reference plane RP1 along the first arcuate surface ARC1 and the second arcuate surface ARC2 to the inlet of the second volute 21. The symmetrical arrangement of the first arcuate surface ARC1 and the second arcuate surface ARC2 allows for more uniform liquid flow within the suction chamber 24, reducing inflow loss and improving overall performance.

[0116] In other embodiments, the first arcuate surface ARC1 and the second arcuate surface ARC2 may also be configured as asymmetrical structures relative to the first reference plane RP1, depending on other engineering requirements.

[0117] refer to Figure 15The first arcuate surface ARC1 has a tangent plane tp1 at the intersection position CP. The perpendicular line of this tangent plane tp1 at the intersection position CP and pointing towards the center of the first arcuate surface ARC1 is the inner normal in1 of the first arcuate surface ARC1 at the intersection position CP. The second arcuate surface ARC2 has a tangent plane tp2 at the intersection position CP. The perpendicular line of this tangent plane tp2 at the intersection position CP and pointing towards the center of the second arcuate surface ARC2 is the inner normal in2 of the second arcuate surface ARC2 at the intersection position CP. The inner normals in1 and in2 have an included angle α.

[0118] Figure 16 Three inner wall forms of the first segment 241 are shown in diagrams a, b, and c. It can be seen that different included angles α can be obtained by designing the first arc-shaped surface ARC1 and the second arc-shaped surface ARC2 with different curvatures. If the included angle α is too small, the intersection point CP will hardly bulge towards the rotation axis 22a, making it difficult to suppress the formation of vortices near the inlet of the second volute 21, leading to inflow losses in the second volute 21 caused by the suction chamber and affecting overall performance. If the preset included angle α is too large, it can easily cause a sudden change in the flow direction of the liquid, forming vortices, resulting in energy loss and increasing liquid flow resistance, thus affecting the liquid flow velocity. Therefore, in some embodiments, the angle between the inner normal of the first arcuate surface ARC1 at the intersection position CP and the inner normal of the second arcuate surface ARC2 at the intersection position CP is 20° to 50°, for example, 20°, 30°, 39°, 45° or 50°. This can effectively suppress the formation of vortices near the liquid inlet of the second volute 21, and reduce the inflow loss and liquid flow resistance of the second volute 21.

[0119] refer to Figure 16 and Figure 17 In some embodiments, the first segment 241 further includes a contracting inlet 241a connected to the secondary volute 21. The contracting inlet 241a helps reduce turbulent dissipation entropy production and wall entropy production, and reduces axial dimensions.

[0120] refer to Figure 13 and Figure 17 In some embodiments, at least a portion of the spatial center line 243 of the suction chamber 24 from the position where the suction chamber 24 connects to the secondary volute 21 to the position where the suction chamber 24 connects to the valve housing 31 is a three-dimensional spiral.

[0121] By making at least a portion of the spatial centerline 243 of the suction chamber 24 a three-dimensional spiral, the liquid flow can be made to flow from the switching valve 30 to the suction chamber 24 along the three-dimensional spiral direction. Compared with the conventional straight cone suction chamber 24 or annular suction chamber 24, this suction chamber 24 is beneficial to improve flow conditions, reduce overall weight and volume, and make the liquid flow inlet of the secondary volute 21 obtain a more uniform velocity field.

[0122] exist Figure 15 In this context, the suction chamber 24 may further include a second section 242 connected to and internally communicating with the valve housing 31. The first section 241 and the second section 242 can be connected through... Figure 15 The secondary impeller 22 is divided by a third reference plane RP3. This third reference plane RP3 may be perpendicular to the first reference plane RP1 and pass through the rotation axis 22a of the secondary impeller 22.

[0123] refer to Figure 15 In some embodiments, the suction chamber 24 includes a second section 242 connected to and internally communicating with the valve housing 31. The portions of the secondary outlet pipe 23 and the second section 242 located on the upper side of the secondary volute 21 are respectively located on both sides of the second reference plane RP2, which is a vertical plane passing through the rotation axis 22a of the secondary impeller 22.

[0124] The portion of the second section 242 of the suction chamber 24 located on the upper side of the secondary volute 21 can be connected to the valve housing 31, which is also located on the upper side of the secondary volute 21, and is located on both sides of the second reference plane RP2 with the secondary outlet pipe 23. This allows the widths of the secondary outlet pipe 23, the second section 242 of the suction chamber 24, and the secondary volute 21 to at least partially overlap in the direction of the rotation axis 22a of the secondary impeller 22, thereby helping to reduce the overall width of the equipment in this direction and save space.

[0125] refer to Figure 15 In some embodiments, the width of the second segment 242 gradually increases in the cross-section perpendicular to the rotation axis 22a of the secondary impeller 22 in the direction from the position where the suction chamber 24 connects to the valve housing 31 to the position where the suction chamber 24 connects to the secondary volute 21. Figure 15 In the second segment 242, we can see that the width w1 of the part closer to the valve housing 31 is smaller than the width w2 of the part farther away from the valve housing 31.

[0126] refer to Figure 3In some embodiments, the self-priming pump 71 further includes a drive shaft 61 and a bearing support structure. The drive shaft 61 passes through the first-stage volute 11 and the second-stage volute 21, and is drively connected to both the first-stage impeller 12 and the second-stage impeller 22. The bearing support structure is connected to the drive shaft 61 and is configured to provide bearing support for the drive shaft 61.

[0127] exist Figures 1-8 In the coordinate system, the x-direction can be parallel to the axis of the transmission shaft 61, the z-direction can be parallel to the vertical direction and perpendicular to the x-direction, and the y-direction is perpendicular to both the x-direction and the z-direction.

[0128] exist Figure 3 In the process, the drive shaft 61 passes sequentially through the first-stage volute 11, the second bearing housing a5, and the secondary volute 21. The drive shaft 61 is radially connected to the first-stage impeller 22 via a key a9. The drive shaft 61 is radially connected to the first-stage mechanical seal sleeve a10 and the first mechanical seal a11 via a second key a12. The first-stage impeller 22, the first-stage mechanical seal sleeve a10, the first mechanical seal a11, the first-stage volute 11, the first bearing a15, the intermediate retaining sleeve a17, and the secondary mechanical seal sleeve a26 are axially pressed together by the impeller nut a8.

[0129] The outer extension of the first-stage impeller 22 is sealed to the first-stage volute 11 via a sealing ring 16. The first-stage mechanical seal sleeve a10 is radially sealed to the second skeleton oil seal a13 and the inner sealing plate a14. The inner sealing plate a14 is axially fixed by a rubber cap a7. The drive shaft 61 is radially fixed to the second bearing seat a5 via the first bearing a15. The intermediate retaining sleeve a17 is sealed to the secondary volute 21 via the first mechanical seal a11.

[0130] The drive shaft 61 is radially connected to the secondary impeller 22 via the second flat key a12. The suction chamber 24 is connected to the first bearing housing a3 and the bearing sealing cover a4. The mechanical seal retaining ring a19, the set screw a20, the second mechanical seal a21, and the bearing sealing cover a4 are connected and sealed to the drive shaft 61. The drive shaft 61 is sealed to the bearing sealing cover a4 via the third skeleton oil seal a22.

[0131] The bearing retaining ring a23, the second bearing a27, the third bearing housing a24, and the bushing nut a1 are axially connected. The bushing nut a1 is sealed to the first bearing housing a3 via the first skeleton oil seal a2. The fourth flat key a25 is connected to an external engine or motor to provide power to the water pump.

[0132] The first-stage volute 11 is axially connected to the second bearing housing a5 and the suction chamber 24 in sequence. The other end of the first-stage volute 11 is connected to the first-stage liquid outlet pipe 13. The other end of the suction chamber 24 is connected to the secondary liquid outlet pipe 24. The vacuum liquid inlet box 41 is connected to the mounting base 46 connected to the suction chamber 24, and the vacuum liquid inlet box 41 is connected to the first-stage volute 11 via a gas guide pipe 43 and a tapered joint 45. The plug a16 is connected to the threads located at the bottom of the secondary volute 21 and the first-stage volute 11, respectively.

[0133] exist Figure 3 In this bearing support structure, the first bearing housing a3, the bearing sealing gland a4, the second bearing housing a5, the primary mechanical seal bushing a10, the first mechanical seal a11, the second skeleton oil seal a13, the first bearing a15, the intermediate retaining sleeve a17, the mechanical seal retaining ring a19, the third skeleton oil seal a22, the bearing retaining ring a23, the third bearing housing a24, the secondary mechanical seal bushing a26, the second bearing a27, etc.

[0134] Figure 20 This is a schematic diagram of the installation structure of some embodiments of the drainage operation equipment disclosed herein. (Reference) Figure 20 This disclosure provides a drainage operation device, including a self-priming pump 71 as described in any of the preceding embodiments. The drainage operation device using the aforementioned self-priming pump 71 can meet drainage needs under different head and flow rates, improving the adaptability of drainage operations to various scenarios.

[0135] In some embodiments, the self-priming pump 71 includes a vacuum priming tank 41 and a drive shaft 61, the drive shaft 61 passing through the first-stage volute 11 and the second-stage volute 21, and being drively connected to both the first-stage impeller 12 and the second-stage impeller 22. (Reference) Figure 20 The drainage equipment may further include: a tracked chassis 72, an engine 73, a vacuum pump 74, and a clutch 75. The engine 73, the vacuum pump 74, and the self-priming pump 71 are all mounted on the tracked chassis 72. The engine 73 is connected to the drive shaft 61 via the clutch 75, and the vacuum pump 74 is connected to the interface of the vacuum priming tank 41. The drainage equipment may also include an electrical system, a hydraulic system, and a battery.

[0136] Figure 21 This is a schematic diagram illustrating the control principle of an embodiment of the drainage operation equipment disclosed herein. (Reference) Figure 21The hydraulic system may include a hydraulic pump 77, which may be driven by an engine 73. The hydraulic circuit connected to the hydraulic pump 77 is connected to an electro-hydraulic valve 76. The drainage equipment may also include a controller 78, which sends control commands to the engine 73 to drive the drive shaft 61, which is connected to the first-stage impeller 12 and the second-stage impeller 22, to rotate, and to drive the hydraulic pump 77. The controller 78 also sends control commands to the electro-hydraulic valve 76 to respectively realize the extension and retraction of the switching cylinder 34, the opening and closing of the hydraulic plug 5d, and the opening and closing of the hydraulic switch valve 44.

[0137] Figure 22 This is a schematic diagram of the operation process of an embodiment of the drainage equipment disclosed herein. (Reference) Figure 21 and Figure 22 The controller 78 can be set with preset control logic to realize the switching of the operating conditions of the self-priming pump 71 and alarm operations, etc.

[0138] exist Figure 22 When the drainage equipment is started, the engine 73 is ignited, the vacuum pump 74 removes the air from the self-priming pump 71, and the engine 73 engages with the drive shaft 61 through the clutch 75. At this time, the engine 73 drives the first-stage impeller 12 and the second-stage impeller 22 to rotate through the drive shaft 61.

[0139] The engine torque percentage M is monitored in real time, and multiple operating modes can be achieved through multiple thresholds M0, M1, and M2, where M2>M1>M0>0. These operating modes can include high-flow drainage mode, high-lift drainage mode, overload alarm mode, and dry pumping alarm mode.

[0140] refer to Figure 22 In the process example shown, when M0≤M<M1 is satisfied, the self-priming pump enters the parallel operation mode, and the controller sends control commands to the electro-hydraulic valve to cause the switching cylinder to retract, the hydraulic plug to open, and the hydraulic switch valve to open, thereby starting the high-flow drainage mode.

[0141] When M2≤M<M2, the self-priming pump enters the series operation mode. The controller sends a control command to the electro-hydraulic valve, causing the switching cylinder to extend, the hydraulic plug to close, and the hydraulic switch valve to close, thus starting the high-lift drainage mode.

[0142] When M≥M2, an overload alarm is triggered, thus initiating the overload alarm mode.

[0143] When M < M0, a dry pumping alarm is triggered, thus initiating the dry pumping alarm mode.

[0144] The embodiments of this disclosure have now been described in detail. To avoid obscuring the concept of this disclosure, some details known in the art have not been described. Those skilled in the art can fully understand how to implement the technical solutions disclosed herein based on the above description.

[0145] While specific embodiments of this disclosure have been described in detail by way of examples, those skilled in the art should understand that the examples are for illustrative purposes only and not intended to limit the scope of this disclosure. Those skilled in the art should understand that modifications can be made to the above embodiments or equivalent substitutions can be made to some technical features without departing from the scope and spirit of this disclosure. The scope of this disclosure is defined by the appended claims.

Claims

1. A self-priming pump (71) characterized by, The application relates to a pump, comprising: a primary pump body unit (10) comprising a primary volute (11) having a first liquid inlet (IN1), a primary impeller (12) arranged in the primary volute (11), and a primary liquid outlet pipe (13) in communication with the primary volute (11); a secondary pump body unit (20) comprising a secondary volute (21), a secondary impeller (22) arranged in the secondary volute (21), a secondary liquid outlet pipe (23) and a liquid suction chamber (24) in communication with the secondary volute (21); and a switching valve (30) comprising a valve housing (31) having a second liquid inlet (IN2) and a valve core (32) arranged in the valve housing (31), the valve housing (31) being in communication with the liquid suction chamber (24) and the primary volute (11); wherein the switching valve (30) is configured to, when the valve core (32) is in a first position (P1), close the second liquid inlet (IN2) by the valve core (32) and make the liquid suction chamber (24) communicate with the primary volute (11) via the valve housing (31), and when the valve core (32) is in a second position (P2), close the communication passage between the valve housing (31) and the primary volute (11) by the valve core (32) and make the liquid suction chamber (24) communicate with the second liquid inlet (IN2) via the valve housing (31); wherein the switching valve (30) is a rotary slide valve, and the valve core (32) can rotate in the valve housing (31) between the first position (P1) and the second position (P2); the valve housing (31) comprises a hollow cylindrical segment (311) having a first connecting port (311a) for communicating with the primary volute (11), a first outer connecting pipe segment (312) and a second outer connecting pipe segment (313) connected to two sides of the hollow cylindrical segment (311), one end of the first outer connecting pipe segment (312) being in communication with the hollow cylindrical segment (311) and the other end serving as the second liquid inlet (IN2), and one end of the second outer connecting pipe segment (313) being in communication with the hollow cylindrical segment (311) and the other end being in communication with the liquid suction chamber (24) through a second connecting port (313a).

2. The self-priming pump (71) according to claim 1, characterized in that The liquid suction chamber (24) comprises a first section (241) located on a side of the secondary volute (21) away from the primary volute (11), an inner wall of the first section (241) comprises a first arc surface (ARC1) and a second arc surface (ARC2), the first arc surface (ARC1) and the second arc surface (ARC2) intersect on a side of the rotation axis (22a) of the secondary impeller (22) away from the valve housing (31), and a distance from the intersection position (CP) to the rotation axis (22a) of the secondary impeller (22) is less than distances from other positions on the first arc surface (ARC1) and the second arc surface (ARC2) to the rotation axis (22a) of the secondary impeller (22).

3. The self-priming pump (71) according to claim 2, characterized in that The first arc surface (ARC1) and the second arc surface (ARC2) are symmetrically arranged relative to a first reference plane (RP1), and the first reference plane (RP1) passes through the intersection position (CP) and the rotation axis (22a) of the secondary impeller (22).

4. The self-priming pump (71) according to claim 2, characterized in that, An included angle between an inner normal of the first arc surface (ARC1) at the intersection position (CP) and an inner normal of the second arc surface (ARC2) at the intersection position (CP) is 20°-50°.

5. The self-priming pump (71) in accordance with claim 2, characterized by The first section (241) further comprises a converging liquid inlet (241a) connected to the secondary volute (21).

6. The self-priming pump (71) in accordance with claim 1, characterized by At least a part of a space center line (243) of the liquid suction chamber (24) from a position where the liquid suction chamber (24) is connected to the secondary volute (21) to a position where the liquid suction chamber (24) is connected to the valve housing (31) is a three-dimensional spiral line.

7. The self-priming pump (71) according to claim 2, characterized in that, The liquid suction chamber (24) comprises a second section (242) connected to the valve housing (31) and in internal communication, and the secondary liquid outlet pipe (23) and the second section (242) are located on two sides of a second reference plane (RP2) respectively, and the second reference plane (RP2) is a vertical plane passing through the rotation axis (22a) of the secondary impeller (22).

8. The self-priming pump (71) according to claim 7, characterized in that In a direction from the position where the liquid suction chamber (24) is connected to the valve housing (31) to the position where the liquid suction chamber (24) is connected to the secondary volute (21), a width of the second section (242) in a cross section perpendicular to the rotation axis (22a) of the secondary impeller (22) gradually increases.

9. The self-priming pump (71) according to claim 1, characterized in that, Further comprising: A vacuum extraction device (40) configured to extract air in at least one of the primary volute (11) and the secondary volute (21).

10. The self-priming pump (71) in accordance with claim 9, characterized in that The vacuum extraction device (40) comprises: A vacuum liquid suction tank (41) having an interface connected to an external vacuum pump (74); A tee joint (42) having a first end connected to the first liquid inlet (IN1) through a gas guide pipe (43), a second end communicated with the liquid suction chamber (24) through a pipeline, and a third end communicated with the vacuum liquid suction tank (41) through a pipeline; and The tee joint (42) has a first end connected to the first liquid inlet (IN1) through a gas guide pipe (43), a second end communicated with the liquid suction chamber (24) through a pipeline, and a third end communicated with the vacuum liquid suction tank (41) through a pipeline. A liquid control switch valve (44) is arranged on the tee joint (42) or between the tee joint (42) and the liquid suction chamber (24), and is configured to control the communication or disconnection between the gas guide pipe (43) and the liquid suction chamber (24).

11. The self-priming pump (71) in accordance with claim 10, characterized by The vacuum liquid guide box (41) is fixedly arranged on the outer wall of the liquid suction chamber (24) away from the switching valve (30).

12. The self-priming pump (71) in accordance with claim 1, characterized by The valve core (32) has a circular arc-shaped internal passage (321), which is configured to communicate with the second external pipe section (313) and the first connecting port (311a) when the valve core (32) is in the first position (P1), and to smoothly transition with the inner walls of the second external pipe section (313) and the connecting port (311a), and to communicate with the first external pipe section (312) and the second external pipe section (313) when the valve core (32) is in the second position (P2), and to smoothly transition with the inner walls of the first external pipe section (312) and the second external pipe section (313).

13. The self-priming pump (71) in accordance with claim 1, characterized by, In a plane perpendicular to the axis (32a) of the valve core (32), the line connecting the first center (C1) of the connecting port of the hollow cylindrical section (311), the second center (C2) of the position connected with the first external pipe section (312), and the third center (C3) of the position connected with the second external pipe section (313) of the axis (32a) of the valve core (32) is arranged circumferentially at 120°.

14. The self-priming pump (71) in accordance with claim 1, characterized by, The switching valve (30) further comprises: an end plate (33) arranged outside the valve shell (31), fixedly connected with the valve core (32), and jointly rotating with the valve core (32) relative to the valve shell (31); and a switching oil cylinder (34) connected with the end plate (33) at a position deviating from the axis (32a) of the valve core (32), configured to drive the end plate (33) to rotate, so as to drive the valve core (32) to switch positions.

15. The self-priming pump (71) in accordance with claim 1, characterized by, Further comprising: a flap device (51, 52) arranged at the end of at least one of the primary liquid outlet pipe (13) and the secondary liquid outlet pipe (23), for controlling the liquid outlet of at least one of the primary liquid outlet pipe (13) and the secondary liquid outlet pipe (23).

16. The self-priming pump (71) in accordance with claim 15, characterized by The flap device (51, 52) comprises a double-section flap.

17. The self-priming pump (71) in accordance with claim 1, characterized by Further comprising: a transmission shaft (61) penetrating through the primary volute (11) and the secondary volute (21), and in transmission connection with the primary impeller (12) and the secondary impeller (22); and a bearing support structure connected with the transmission shaft (61), and configured to provide bearing support to the transmission shaft (61).

18. A flood operation device characterized by, Comprising: the self-priming pump (71) according to any one of claims 1-17.

19. The flood operation device according to claim 18, characterized in that The self-suction pump (71) comprises a vacuum liquid guiding tank (41) and a transmission shaft (61), the transmission shaft (61) passes through the primary volute (11) and the secondary volute (21), and is in driving connection with the primary impeller (12) and the secondary impeller (22), and the waterlogging drainage operation equipment further comprises a tracked chassis (72), an engine (73), a vacuum pump (74) and a clutch (75), the engine (73), the vacuum pump (74) and the self-suction pump (71) are all arranged on the tracked chassis (72), the engine (73) is connected with the transmission shaft (61) through the clutch (75), and the vacuum pump (74) is in interface connection with the vacuum liquid guiding tank (41).

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