A dual pump system and a cleaning machine using the same

Abstract

The present application relates to a kind of double pump system and the cleaning machine of application has double pump system, double pump system includes upper impeller, lower impeller, spray arm, volute, spray arm is rotatably connected on the top wall of volute by self-locking structure, in the rotating state of spray arm, spray arm and volute always keep the trend of automatic locking.Between the present application provides an open double pump system, the second accommodating cavity in upper portion, first accommodating cavity and upper impeller are bottom spray water supply, the third accommodating cavity in lower portion and lower impeller are top and / or middle spray water supply, since the power of two-way water flow is independently supplied by corresponding pump, the lift and water flow of each water flow are improved, which is beneficial to improve cleaning effect;Double pump system of the present application is convenient to disassemble, clean, and avoid bacterial growth;Spray arm is installed on volute by self-locking structure, and good stability can avoid spray arm and volute from being separated under non-human operation.

Description

Technical Field

[0001] This invention relates to the field of dishwasher technology, specifically to a dual-pump system and a cleaning machine using a dual-pump system. Background Technology

[0002] For countertop and cabinet dishwashers, due to their large washing space, they are generally designed with three spray arms: top, middle, and bottom, to achieve better washing results. During operation, the washing pump delivers water through pipes to the top, middle, and bottom spray arms. The water sprays out from the top, middle, and bottom spray arms, rinses the dishes, and then falls back into the water cup at the bottom of the dishwasher. The washing pump then delivers the fallen water back to the top, middle, and bottom spray arms to complete one cycle.

[0003] For example, Chinese invention patent application CN106859563A, entitled "Energy-Saving Dishwasher" (application number: CN201611232345.5), discloses a structure that includes a cavity for accommodating tableware and providing a cleaning space, a spray system for spraying water to clean the tableware, and a pump for drawing water and supplying water to the spray system. The spray system is disposed within the cavity. The pump's suction end is connected to the cavity, and its supply end is connected to the spray system. The spray system includes an inner water pipe and two or more spray devices, each set of spray devices being disposed on the inner water pipe. The pump's supply end is connected to a water distribution device, which has two or more water outlets corresponding to the two or more spray devices, and the spray devices are connected to the corresponding water outlets. During operation, the water distribution device opens one or more water outlets according to instructions, enabling one or more spray devices to perform cleaning work.

[0004] In existing dishwashers capable of both bottom and top spraying, the pump supplying water to the spraying system typically employs a closed structure. This means the volute of the washing pump is located below the main unit, and a rotating impeller is installed inside. The inlet of the volute is connected to the bottom of the washing chamber, and the outlet is connected to a water divider. This divider splits the water flow into a first branch supplying water to the bottom spraying arms and a second branch supplying water to the top spraying arms. Because the water pressure for both the top and bottom spraying is supplied independently by the washing pump, the head, flow rate, and impact force of the water flow on each branch are significantly reduced after the split, affecting the cleaning effect. Furthermore, the closed volute, fixed below the main unit, is difficult to disassemble and clean, and after prolonged use, bacteria can grow due to residue accumulation, further impacting the washing effect and creating a poor user experience.

[0005] In addition, currently, when installing the spray arm, there is no obvious tactile feedback after installation, making it difficult to determine whether it is installed correctly. Summary of the Invention

[0006] The first technical problem to be solved by the present invention is to provide a dual-pump system that facilitates the connection between the spray arm and the volute, in light of the current state of the prior art.

[0007] The second technical problem to be solved by the present invention is to provide a dual-pump system that can provide power to two separate washing water sources, thereby increasing the head and water flow rate and thus improving the cleaning effect, in view of the current state of the prior art.

[0008] The third technical problem to be solved by the present invention is to provide a dual-pump system that adopts an open volute casing to facilitate disassembly and cleaning, in view of the current state of the prior art.

[0009] The fourth technical problem to be solved by the present invention is to provide a cleaning machine with the above-mentioned dual-pump system, in view of the current state of the prior art.

[0010] The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows:

[0011] A dual-pump system, comprising:

[0012] The upper impeller has a first shaft located at the center and first blades that are circumferentially spaced and extend axially on the circumferential surface of the first shaft;

[0013] The lower impeller has a second shaft located at the center and second blades spaced circumferentially on the circumferential surface of the second shaft;

[0014] A spray arm having a first receiving cavity for mounting the upper part of the first blade, and spray holes in fluid communication with the first receiving cavity being formed on the top wall and / or side wall of the spray arm; and

[0015] A volute is connected to the lower part of the spray arm. The upper part of the volute has a second accommodating cavity for installing the lower part of the first blade. A first water inlet is opened on the side wall of the volute to supply water into the second accommodating cavity. The lower part of the volute has a third accommodating cavity for installing the lower impeller. A second water inlet is opened on the side wall and / or bottom wall of the volute to supply water into the third accommodating cavity and a water outlet is opened from the third accommodating cavity.

[0016] The spray arm is rotatably connected to the top wall of the volute via a self-locking structure. When the spray arm is rotating, the spray arm and the volute always maintain an automatic locking tendency.

[0017] In this invention, a radially extending support plate is provided on the outer peripheral wall of the upper part of the volute. The support plate is provided with a retaining ring that can always maintain a locking tendency with the support plate when the spray arm is rotating. The bottom wall of the spray arm is provided with a retaining foot that can rotatably pass through the retaining ring and engage with the bottom wall of the retaining ring for limiting, thereby detachably connecting the spray arm to the top of the volute for easy disassembly and assembly.

[0018] Preferably, the upper surface of the support plate is provided with a limiting part extending radially and having a cross-section of ∩. The first side wall of the limiting part has a notch arranged near the outer end, and a groove extends inward along the notch to form the limiting part. In the assembled state, the limiting part is accommodated inside the retaining ring. The inner peripheral wall of the retaining ring is provided with a protrusion that can slide into the groove through the notch, thus achieving an interference fit. The protrusion and the groove together constitute the self-locking structure. During assembly, first connect the retaining ring to the spray arm, then insert the retaining ring outside the limiting part, and then rotate the spray arm clockwise, causing the protrusion to slide into the groove through the notch and into the innermost end of the groove through an interference fit. At this time, the user will clearly feel that the assembly is in place. Since the spray arm also rotates clockwise, which is consistent with the locking direction of the protrusion and the groove, it can be ensured that the spray arm is always firmly locked on the volute and will not detach from the volute.

[0019] Further preferably, the inner top wall of the slot is formed by a series of interconnected elements: a gradually downward sloping surface from the notch inwards, a relatively horizontal first plane, a second plane lower than the first plane, and a third plane level with the first plane. In the assembled state, the protrusion contacts and engages with the third plane and the inner wall of the slot. This structure helps to further improve the stability of the spray arm and volute assembly, and also improves the user's operating feel, allowing for accurate perception of the assembled state.

[0020] In the above scheme, a partition is provided in the middle of the volute to separate the second and third accommodating cavities into relatively independent chambers. This independence facilitates water supply to the lower spray via the upper impeller and to the top and / or middle spray via the lower impeller, reducing fluid disturbance between them, minimizing energy loss, and improving water head, flow rate, and spray force.

[0021] Preferably, the third accommodating cavity is located below the partition and is generally disk-shaped. The second inlet is located on the bottom wall of the volute, and the outlet is located on the side wall of the volute and is tangentially connected to the third accommodating cavity via a guide pipe. This structure helps to reduce the loss of water flow output from the third accommodating cavity.

[0022] Preferably, the second receiving cavity is located above the partition and extends vertically, and the inner diameter of the second receiving cavity is smaller than the inner diameter of the third receiving cavity and is adapted to the lower part of the first blade. This structure helps to reduce the energy loss of water flow when passing through the second receiving cavity.

[0023] Preferably, a laterally extending ∩-shaped surrounding plate is provided on the top wall of the partition, which together with the partition forms a water inlet channel communicating with the second accommodating cavity. The outer port of the water inlet channel constitutes the first water inlet. This structure not only facilitates manufacturing but also, by placing the water inlet channel at the bottom of the second accommodating cavity, helps reduce water flow disturbance and further minimizes energy loss of the water flow as it passes through the second accommodating cavity.

[0024] Preferably, the bottom wall of the spray arm has a third water inlet corresponding to the first receiving cavity, which is connected to the upper port of the second receiving cavity. The diameter of the third water inlet is larger than the inner diameter of the second receiving cavity, and the upper part of the volute gradually widens its inner diameter near the upper end of the second receiving cavity to form a guide portion that can smoothly transition and connect with the inner bottom wall of the first receiving cavity. This structure helps to reduce the energy loss of water flow during the process of entering the first receiving cavity from the second receiving cavity.

[0025] Preferably, the outer edge of the guide portion is arranged near the inner edge of the third water inlet, and a baffle extending radially and resting on the bottom wall of the spray arm is provided on the outer peripheral wall of the guide portion, with the outer edge of the baffle corresponding to the inner edge of the retaining foot. This structure helps to improve the sealing performance at the third water inlet, preventing water leakage from affecting the head of the bottom spray.

[0026] In this invention, the upper part of the first blade is a centrifugal blade and the lower part is an axial flow blade; the second blade is a centrifugal blade.

[0027] In the above-described solutions, the dual-pump system further includes a drive component for rotating the upper and lower impellers. This drive component is located below the volute casing with its output shaft facing upwards. The output shaft extends from bottom to top through the volute casing into the first accommodating cavity of the spray arm and is connected to both the lower and upper impellers. This structure utilizes a single power source to construct the dual-pump system, simplifying the overall structure, reducing production costs, and facilitating control of the water supply.

[0028] Preferably, the output shaft is radially limited by the upper and lower impellers, and a nut is provided at the upper end of the output shaft to prevent the upper impeller from moving axially along the output shaft. This structure facilitates disassembly and assembly. After removing the spray arm from the retaining ring, the nut can be unscrewed to remove the upper impeller, allowing for cleaning of the spray arm, upper impeller, and the upper cavity of the volute, thus preventing bacterial growth and improving cleaning effectiveness.

[0029] A cleaning machine using the above-mentioned dual-pump system includes a housing and a water supply pipe that can transport water from the bottom of the housing upwards, characterized in that: the volute is constrained on the bottom wall of the housing and the water outlet is connected to the lower end of the water supply pipe.

[0030] Preferably, the water supply pipeline has relatively independent first branch pipe and second branch pipe. The first branch pipe is used to transport water to the middle of the tank, and the second branch pipe is used to transport water to the top of the tank. This structure enables spraying at the lower, middle, and top layers, which helps improve the cleaning effect.

[0031] Preferably, the bottom of the housing is further provided with a water distribution valve for controlling the flow of the first and second branch pipes. The inlet of the water distribution valve is connected to the outlet of the volute, the first outlet of the water distribution valve is connected to the input end of the first branch pipe, and the second outlet of the water distribution valve is connected to the input end of the second branch pipe. This structure facilitates the control of the usage status of the middle and top layer spraying as needed. For example, the first branch pipe can be closed and the second branch pipe opened, with only the top layer spraying; alternatively, the first branch pipe can be opened and the second branch pipe closed, with only the middle layer spraying, to meet more usage requirements.

[0032] Compared with the prior art, the advantages of the present invention are as follows: The present invention provides an open dual-pump system, wherein the second accommodating chamber, the first accommodating chamber, and the upper impeller located in the upper part supply water for bottom spraying, and the third accommodating chamber and the lower impeller located in the lower part supply water for top and / or middle spraying. Since the power of the two water flows is independently supplied by the corresponding pumps, the head and flow rate of each water flow are increased, which is beneficial to improving the cleaning effect. The dual-pump system of the present invention is easy to disassemble and assemble. The spray arm can be removed from the volute to clean the spray arm, the upper impeller, and the volute, avoiding bacterial growth. The spray arm is installed on the volute through a self-locking structure, which has good stability and can prevent the spray arm from detaching from the volute without human intervention. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the dual-pump system in an embodiment of the present invention;

[0034] Figure 2 for Figure 1 A structural diagram from another angle;

[0035] Figure 3 This is a cross-sectional view of the dual-pump system according to an embodiment of the present invention;

[0036] Figure 4 This is a schematic diagram of the volute structure in an embodiment of the present invention;

[0037] Figure 5 for Figure 4 A structural diagram from another angle;

[0038] Figure 6 This is a cross-sectional view of the volute in an embodiment of the present invention;

[0039] Figure 7This is a schematic diagram of the cleaning machine in an embodiment of the present invention;

[0040] Figure 8 This is a partial structural diagram of the volute in an embodiment of the present invention;

[0041] Figure 9 This is an assembly diagram of the volute and spray arm in an embodiment of the present invention. Detailed Implementation

[0042] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0043] The dual-pump system of this embodiment can be applied to larger dishwashers to supply water for bottom spray, top spray and / or middle spray, but the dual-pump system of this embodiment is not limited to this usage environment.

[0044] like Figures 1-9 As shown, the dual-pump system of this embodiment includes an upper impeller 1, a lower impeller 2, a spray arm 3, a volute 4, and a drive component 5.

[0045] The upper impeller 1 has a first shaft 11 located at the center and a plurality of first blades 12 distributed circumferentially and extending axially on the circumferential surface of the first shaft 11. The upper part of the first blades 12 is a centrifugal blade and the lower part is an axial flow blade.

[0046] The lower impeller 2 has a second shaft 21 located at the center and a plurality of second blades 22 distributed circumferentially on the circumferential surface of the second shaft 21. The second blades 22 are centrifugal blades.

[0047] The spray arm 3 has a body extending in the length direction. The central part of the body has a first accommodating cavity 31 for mounting the upper part of the first blade 12. The two sides of the body have flow channels communicating with the first accommodating cavity 31. The top wall of the spray arm 3 has spray holes 32 communicating with the flow channels.

[0048] The volute 4 is connected to the lower part of the spray arm 3. The upper part of the volute 4 has a second accommodating cavity 41 for installing the lower part of the first blade 12. The side wall of the volute 4 has a first water inlet 411 for water to enter the second accommodating cavity 41. The lower part of the volute 4 has a third accommodating cavity 42 for installing the lower impeller 2. The bottom wall of the volute 4 has a second water inlet 421 for water to enter the third accommodating cavity 42, and the side wall has a water outlet 422 for water to be discharged from the third accommodating cavity 42.

[0049] The driving component 5 is a motor, located below the volute 4 with the output shaft 51 facing upward. The output shaft 51 passes through the volute 4 from bottom to top and extends into the first accommodating cavity 31 of the spray arm 3, and is connected to the lower impeller 2 and the upper impeller 1 respectively, for driving the upper impeller 1 and the lower impeller 2 to rotate.

[0050] Specifically, such as Figure 3 , 6 As shown, a partition 43 is provided in the middle of the volute 4 to separate the second accommodating cavity 41 and the third accommodating cavity 42 into relatively independent cavities. This relative independence of the second accommodating cavity 41 and the third accommodating cavity 42 facilitates the supply of water to the lower spray via the upper impeller 1 and to the top and / or middle spray via the lower impeller 2, reducing fluid disturbance between them, minimizing energy loss, and improving water head, water flow rate, and spray force.

[0051] The aforementioned third accommodating cavity 42 is located below the partition plate 43 and is roughly disc-shaped. The second inlet 421 is opened in the center of the bottom wall of the volute 4, and the outlet 422 is tangentially connected to the third accommodating cavity 42 through the guide pipe 423. This structure helps to reduce the loss of the water output capacity of the third accommodating cavity 42.

[0052] The second receiving cavity 41 is located above the partition 43 and extends vertically. The inner diameter of the second receiving cavity 41 is smaller than the inner diameter of the third receiving cavity 42 and is adapted to the lower part of the first blade 12. This structure helps to reduce the energy loss of water flow when it flows through the second receiving cavity 41.

[0053] like Figure 4 , 5 As described in section 6, a laterally extending U-shaped enclosure 431 is provided on the top wall of the partition 43. The enclosure 431 and the partition 43 together form a water inlet channel 432 that communicates with the second accommodating cavity 41. The outer port of the water inlet channel 432 constitutes the first water inlet 411. This structure not only facilitates manufacturing, but also places the water inlet channel 432 at the bottom of the second accommodating cavity 41, which helps to reduce water flow disturbance and further reduce the energy loss of water flow when passing through the second accommodating cavity 42.

[0054] In this embodiment, the spray arm 3 is rotatably connected to the top wall of the volute 4 via a self-locking structure 100. When the spray arm 3 is rotating, the spray arm 3 and the volute 4 always maintain an automatic locking tendency.

[0055] Specifically, a radially extending support plate 44 is provided on the outer peripheral wall of the upper part of the volute 4. The support plate 44 is provided with a retaining ring 441 that can always maintain a locking tendency with the support plate 44 when the spray arm 3 is rotating. The bottom wall of the spray arm 3 is provided with a retaining foot 33 that can rotatably pass through the retaining ring 441 and is engaged and limited with the bottom wall of the retaining ring 441, thereby rotatably connecting the spray arm 3 to the retaining ring 441.

[0056] like Figure 4 , 8As shown, the upper surface of the support plate 44 is provided with a limiting part 442 that extends radially and has a cross-section of ∩. The first side wall of the limiting part 442 has a notch 443 arranged near the outer end. A groove 444 extends inward from the notch 443 into the limiting part 442. In the assembled state, the limiting part 442 is accommodated inside the retaining ring 441. The inner peripheral wall of the retaining ring 441 is provided with a protrusion 445 that can slide into the groove 444 through the notch 442 so that the groove 444 is interference-fitted. The protrusion 445 and the groove 444 together constitute the self-locking structure 100.

[0057] like Figure 8 As shown, the inner top wall of the slot 444 is formed by a slope 400 that gradually slopes downward from the outside to the inside from the notch 443, a relatively horizontal first plane 401, a second plane 402 that is lower than the first plane 401, and a third plane 403 that is level with the first plane 402 in sequence. When assembled, the protrusion 445 contacts and engages with the third plane 403 and the inner sidewall 404 of the slot 444.

[0058] like Figure 9 As shown, when assembling the spray arm 3 and the volute 4, first connect the retaining ring 441 to the spray arm 3, then insert the retaining ring 441 on the outside of the limiting part 442, and then rotate the spray arm 3 clockwise so that the protrusion 445 slides from the notch 443 into the slot 444, and slides into the innermost end of the slot 444 through an interference fit. At this time, the user will clearly feel that the assembly is in place. Since the spray arm 3 also rotates clockwise when rotating, which is consistent with the locking direction of the protrusion 445 and the slot 444, it can ensure that the spray arm 3 is always firmly locked on the volute 4 and will not detach from the volute 4.

[0059] like Figure 3 As shown, a third water inlet 34 is formed on the bottom wall of the spray arm 3, corresponding to the first receiving cavity 31. This third water inlet 34 is connected to the upper port of the second receiving cavity 41. The diameter of the third water inlet 34 is larger than the inner diameter of the second receiving cavity 41. The upper part of the volute 4 gradually expands its inner diameter near the upper end of the second receiving cavity 41, forming a guide portion 412 that can smoothly transition and connect with the inner bottom wall of the first receiving cavity 31. This structure helps to reduce the energy loss of water flow from the second receiving cavity 41 into the first receiving cavity 31. The outer edge of the guide portion 412 is arranged near the inner edge of the third water inlet 34. A baffle 413 extending radially and supported on the bottom wall of the spray arm 3 is provided on the outer peripheral wall of the guide portion 412. The outer edge of the baffle 413 is arranged corresponding to the inner edge of the retaining foot 33. This structure helps to improve the sealing performance at the third water inlet 34, preventing water leakage and affecting the head of the bottom spray.

[0060] In this embodiment, the output shaft 51 is radially limited by the upper impeller 1 and the lower impeller 2, respectively. A nut is provided at the upper end of the output shaft 51 to prevent the upper impeller 1 from moving axially along the output shaft 51. With the above structure, disassembly and assembly are convenient. After removing the spray arm 3 from the retaining ring 441, the nut can be unscrewed to remove the upper impeller 1. The spray arm 3, the upper impeller 1, and the upper cavity of the volute 4 can then be cleaned to prevent bacterial growth and improve the cleaning effect.

[0061] In this embodiment, as Figure 7 As shown, the cleaning machine using the aforementioned dual-pump system includes a housing 6 and a water supply pipe 7 that transports water from the bottom of the housing 6 upwards. A volute 4 is constrained to the inner bottom wall of the housing 6, and its outlet 422 is connected to the lower end of the water supply pipe 7. The water supply pipe 7 has two relatively independent branches: a first branch pipe 71 and a second branch pipe 72. The first branch pipe 71 transports water to the middle of the housing, and the second branch pipe 72 transports water to the top of the housing. This structure enables spraying at the lower, middle, and top layers, which improves the cleaning effect.

[0062] The bottom of the aforementioned housing 6 is also equipped with a water distribution valve 8 for controlling the flow of the first branch pipe 71 and the second branch pipe 72. The inlet of the water distribution valve 8 is connected to the outlet 422 of the volute 4, the first outlet of the water distribution valve 8 is connected to the input end of the first branch pipe 71, and the second outlet of the water distribution valve 8 is connected to the input end of the second branch pipe 72. This structure facilitates the control of the usage status of the middle and top layer spraying as needed. For example, the first branch pipe 71 can be closed and the second branch pipe 72 can be opened for top layer spraying only; alternatively, the first branch pipe 71 can be opened and the second branch pipe 72 can be closed for middle layer spraying only, thus meeting more usage requirements.

[0063] In use, the output shaft 51 of the drive unit 5 rotates, driving the upper impeller 1 and the lower impeller 2 to rotate. The axial flow blades at the lower part of the first blade 12 draw water from the first inlet 411 into the second accommodating cavity 41 and transport it upward to the first accommodating cavity 31. The water in the first accommodating cavity 31 is sprayed out through the nozzle 32 under the action of the upper part of the first blade 12. The second blade 22 draws water from the second inlet 421 into the third accommodating cavity 42 and transports it circumferentially along the guide pipe 423 through the outlet 422 to the water supply pipe 7. The water supply pipe 7 transports the water upward for top and / or middle spraying.

[0064] The specification and claims of this invention use terms indicating direction, such as "front," "rear," "upper," "lower," "left," "right," "side," "top," and "bottom," to describe various exemplary structural parts and elements of the invention. However, these terms are used herein merely for ease of explanation and are determined based on the exemplary orientations shown in the accompanying drawings. Since the embodiments disclosed in this invention can be arranged in different orientations, these terms indicating direction are for illustrative purposes only and should not be considered as limitations. For example, "upper" and "lower" are not necessarily limited to directions opposite to or consistent with the direction of gravity.

[0065] The term "fluid connectivity" as used in this invention refers to the spatial relationship between two components or parts (hereinafter referred to as the first part and the second part, respectively), that is, a fluid (gas, liquid, or a mixture of both) can flow from the first part along a flow path and / or be transported to the second part. This can be a direct connection between the first part and the second part, or an indirect connection between the first part and the second part through at least one third party. This third party can be a fluid channel such as a pipe, channel, conduit, guide, hole, or groove, or a chamber or combination thereof that allows fluid to flow through.

Claims

1. A dual-pump system, characterized in that... include: The upper impeller (1) has a first shaft (11) located at the center and first blades (12) that are circumferentially spaced and extend axially on the circumferential surface of the first shaft (11); The lower impeller (2) has a second shaft (21) located at the center and second blades (22) spaced circumferentially on the circumferential surface of the second shaft (21); A spray arm (3) having a first receiving cavity (31) for mounting the upper part of the first blade (12), and spray holes (32) in fluid communication with the first receiving cavity (31) are formed on the top wall and / or side wall of the spray arm (3); and The volute (4) is connected to the lower part of the spray arm (3). The upper part of the volute (4) has a second accommodating cavity (41) for installing the lower part of the first blade (12). The second accommodating cavity (41) is connected to the first accommodating cavity (31). The side wall of the volute (4) has a first water inlet (411) for water to enter the second accommodating cavity (41). The lower part of the volute (4) has a third accommodating cavity (42) for installing the lower impeller (2). The side wall and / or bottom wall of the volute (4) have a second water inlet (421) for water to enter the third accommodating cavity (42) and a water outlet (422) for water to be discharged from the third accommodating cavity (42). The spray arm (3) is rotatably connected to the top wall of the volute (4) through a self-locking structure (100). When the spray arm (3) is rotating, the spray arm (3) and the volute (4) always maintain an automatic locking tendency. The middle part of the volute (4) is provided with a partition (43) for separating the second accommodating cavity (41) and the third accommodating cavity (42) into relatively independent cavities; the bottom wall of the spray arm (3) is provided with a third water inlet (34) corresponding to the first accommodating cavity (31), and the third water inlet (34) is connected to the upper port of the second accommodating cavity (41).

2. The dual-pump system according to claim 1, characterized in that: A radially extending support plate (44) is provided on the outer peripheral wall of the upper part of the volute (4). A retaining ring (441) is provided on the support plate (44) so ​​that it can always maintain a locking tendency with the support plate (44) when the spray arm (3) is rotating. A retaining foot (33) is provided on the bottom wall of the spray arm (3) so that it can rotate through the retaining ring (441) and is engaged and limited with the bottom wall of the retaining ring (441).

3. The dual-pump system according to claim 2, characterized in that: The upper surface of the support plate (44) is provided with a limiting part (442) that extends radially and has a cross-section of ∩. The first side wall of the limiting part (442) has a notch (443) arranged near the outer end. A groove (444) is formed by extending along the notch (443) into the limiting part (442). In the assembled state, the limiting part (442) is accommodated inside the retaining ring (441). The inner peripheral wall of the retaining ring (441) is provided with a protrusion (445) that can slide into the groove (444) through the notch (443) to achieve an interference fit. The protrusion (445) and the groove (444) together constitute the self-locking structure (100).

4. The dual-pump system according to claim 3, characterized in that: The inner top wall of the slot (444) is formed by a slope (400) that gradually slopes downward from the outside to the inside from the notch (443), a relatively horizontal first plane (401), a second plane (402) that is lower than the first plane (401), and a third plane (403) that is level with the first plane (401) in sequence. When assembled, the protrusion (445) contacts and engages with the third plane (403) and the inner sidewall of the slot (444).

5. The dual-pump system according to any one of claims 1 to 4, characterized in that: The third accommodating cavity (42) is located below the partition plate (43) and is generally disc-shaped. The second water inlet (421) is opened on the bottom wall of the volute (4), and the water outlet (422) is opened on the side wall of the volute (4) and is tangentially connected to the third accommodating cavity (42) through the guide pipe (423).

6. The dual-pump system according to any one of claims 1 to 4, characterized in that: The second accommodating cavity (41) is located above the partition (43) and extends vertically. The inner diameter of the second accommodating cavity (41) is smaller than the inner diameter of the third accommodating cavity (42) and is adapted to the lower part of the first blade (12).

7. The dual-pump system according to claim 6, characterized in that: A transversely extending U-shaped enclosure (431) is provided on the top wall of the partition (43). The enclosure (431) and the partition (43) together form a water inlet channel (432) that communicates with the second accommodating cavity (41). The outer port of the water inlet channel (432) constitutes the first water inlet (411).

8. The dual-pump system according to any one of claims 1 to 4, characterized in that: The diameter of the third inlet (34) is larger than the inner diameter of the second accommodating cavity (41). The upper part of the volute (4) gradually expands its inner diameter near the upper end of the second accommodating cavity (41) to form a guide part (412) that can smoothly transition and connect with the inner bottom wall of the first accommodating cavity (31).

9. The dual-pump system according to claim 8, characterized in that: The outer edge of the guide section (412) is arranged near the inner edge of the third water inlet (34), and a baffle (413) is provided on the outer peripheral wall of the guide section (412) extending radially and supported on the bottom wall of the spray arm (3).

10. The dual-pump system according to any one of claims 1 to 4, characterized in that: The upper part of the first blade (12) is a centrifugal blade and the lower part is an axial flow blade; the second blade (22) is a centrifugal blade.

11. The dual-pump system according to any one of claims 1 to 4, characterized in that: It also includes a drive unit (5) for driving the upper impeller (1) and the lower impeller (2) to rotate. The drive unit (5) is located below the volute (4) and the output shaft (51) is arranged upward. The output shaft (51) passes through the volute (4) from bottom to top and extends into the first receiving cavity (31) of the spray arm (3) and is connected to the lower impeller (2) and the upper impeller (1) respectively.

12. The dual-pump system according to claim 11, characterized in that: The output shaft (51) is radially limited by the upper impeller (1) and the lower impeller (2) respectively. A nut is provided at the upper end of the output shaft (51) to prevent the upper impeller (1) from moving axially along the output shaft (51).

13. A cleaning machine using the dual-pump system according to any one of claims 1 to 12, comprising a housing (6) and a water supply pipe (7) capable of conveying water from the bottom of the housing (6) upwards, characterized in that: The volute (4) is constrained on the bottom wall of the box (6) and the water outlet (422) is connected to the lower end of the water supply pipe (7).

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