Centrifugal pump with electric heating function

Abstract

A centrifugal pump with an electric heating function is characterized in that an electric heating pipe is arranged in an annular cylindrical cavity surrounding the periphery of a motor of the pump, a heating main body for heating pump liquid is integrally in a circular ring shape, an annular flow channel is arranged around the heating main body, liquid flow conveyed by an upstream communicating pump volute chamber is heated by the electric heating pipe, and then the downstream communicating pump volute chamber is pumped out through a discharge port of the pump; the heating main body of the electric heating tube is prevented from touching the outer wall of the motor to cause overhigh temperature rise of the stator, and the heating main body is prevented from touching the cavity shell to cause overheat deformation and even fusing; on one hand, compared with an existing mode that a thick-film cylindrical heater is adopted to divide a cavity to form an inner peripheral runner and an outer peripheral runner, work is stable, and the dry burning resistance is high; on the other hand, compared with an existing electric heating tube cast isolation part for separating a cavity to form inner and outer peripheral runners, the weight is light, the size is small, and the manufacturing cost is low; and in addition, compared with the existing water flow return reversing between the inner and outer peripheral flow channels, the annular flow channel has the advantages that the water flow is gentle, the flow channel resistance is reduced, and the efficiency of the pump is improved.

Description

Technical Field

[0001] This utility model relates to a centrifugal pump with electric heating function, which may be classified as F04D 13 / 06, F04D29 / 44, or F04D29 / 58 by IPC. Background Technology

[0002] Existing centrifugal pumps with heating functions, as described in Chinese patent CN114060288B, include a heater assembly, a rotor assembly, a pump cover, an inner water jacket, and a pump body. The heater assembly comprises an inner circumferential flow channel sleeve, a cylindrical outer circumferential flow channel sleeve, and a cylindrical heater (thick-film heater) with an insulating thin-layer electric heating film covering its outer surface. The heater is installed within the cavity enclosed by the inner and outer circumferential flow channel sleeves. This pump's heater assembly and the inner and outer circumferential flow channels are complex and cumbersome to assemble, impacting production efficiency and product reliability. Thick-film heating requires high density and speed, necessitating rapid heat removal from the flow channel to prevent overheating and damage to the thick film, thus placing high demands on the flow channel design. Another type of centrifugal pump integrating an electric heating component, as described in Chinese invention patent application number CN202411051367.6, uses cast aluminum to encase the electric heating tube body and cast it into a hollow columnar isolation part. After assembly, it forms inner and outer peripheral flow channels. Since the baffle block, guide block, partition block, and isolation block that separate the flow channels are die-cast along with the casting, the die-casting mold is complex and costly. Moreover, the casting is heavy and bulky, resulting in an excessively large pump body size. When installed in vehicles or household appliances, it is difficult to install in the narrow space provided by its design.

[0003] For terms and common knowledge, unless otherwise specified in this manual, please refer to the national standard GB / T 33925.1 "General terms, definitions, quantities, characters and units for liquid pumps and their devices - Part 1: Liquid pumps" and GB / T 7021 "Centrifugal pump nomenclature and terminology", the mechanical industry standard JB / T5415 "Miniature centrifugal electric pumps", the "Mechanical Engineering Handbook" and "Electrical Engineering Handbook" published by China Machine Press in 1983 or 1997, the "Pump Theory and Technology" published by China Machine Press in 2014, the "Modern Pump Theory and Technology" published by China Aerospace Press in 2011, the "Pumps and Fans" published by China Electric Power Press in 2008, and patent documents CN114060288B and CN202411051367.6. Utility Model Content

[0004] To address the problems described in the background section, this utility model provides the following technical solution:

[0005] A centrifugal pump with an electric heating function includes: an electric motor, whose axially driven impeller drives the pump liquid through a volute; an annular cavity surrounding the outer periphery of the electric motor; an electric heating tube having a heating body for heating the pump liquid within a cavity built into the cavity, the heating body being generally an open annulus, and having a first external portion and a second external portion extending in the same direction perpendicular to the annulus at the opening, connecting to both ends of the heating body; an inner ring plate, the inner ring plate being generally annular, and located axially between the heating body and the inner periphery of the cavity; an outer ring plate, the outer ring plate being generally annular, and located axially between the heating body and the outer periphery of the cavity; and an upper ring. The upper ring plate is circular in shape and is located between the upper end of the heating body and the cavity along a direction perpendicular to the axial direction. There are gaps between the outer ring plate, inner ring plate, upper ring plate and the heating body of the electric heating tube. The opening of the heating body is provided with a first partition that connects to the inner ring plate inward and the outer ring plate outward. The first and second external connecting parts of the electric heating tube are sealed and pass through and extend out of the rear end of the cavity for connecting to the power supply. The inner ring plate, outer ring plate, upper ring plate, rear end of the cavity and the first partition enclose the heating body to form an annular flow channel. The annular flow channel communicates with the volute chamber through the inner side of the first partition and with the discharge port of the electric pump through the outer side of the first partition.

[0006] This centrifugal pump features a cylindrical cavity surrounding the outer circumference of the motor housing a ring-shaped heating element for heating the pumped liquid. An annular flow channel connects this heating element to the volute and discharge port. The liquid flowing upstream into the pump volute is heated by the heating element and then pumped out downstream through the discharge port. This design prevents the heating element from contacting the motor's outer wall, which could cause excessive stator temperature rise, and also avoids contact between the heating element and the pump casing, which could lead to overheating, deformation, or even melting. Firstly, compared to existing technologies using thick-film cylindrical heaters to separate the cavity into inner and outer flow channels, this design offers more stable operation and stronger resistance to dry burning. Secondly, compared to existing technologies using cast aluminum to encase the heating element and cast insulating parts to separate the cavity into inner and outer flow channels, this design is lighter, smaller, and has lower manufacturing costs. Thirdly, compared to existing designs where the inner and outer flow channels have flow reversals, the annular flow channel provides a smoother flow, reducing flow resistance and improving pump efficiency. A typical design for this type of centrifugal pump with electrothermal function also includes:

[0007] An annular flow guide made of metal is built into the cavity; the outer ring plate is split into a first outer ring plate and a second outer ring plate, and the inner ring plate is split into a first inner ring plate and a second inner ring plate; the annular flow guide is integrally formed with the first inner ring plate, the first outer ring plate, the upper ring plate, and the first partition; the rear end of the cavity is surrounded by a metal base, the base has a through hole through which the first and second external parts of the heating pipe pass, and the base is integrally formed with the second inner ring plate and the second outer ring plate inside the cavity; after the base, the heating pipe, and the annular flow guide are assembled, the first outer ring plate and the second outer ring plate are combined to form the outer ring plate, and the first inner ring plate and the second inner ring plate are combined to form the inner ring plate; the annular flow channel is built into the cavity of the cavity without sealing.

[0008] The typical design uses low-cost plastic for the pump housing and high-precision, non-deformable metal for the inner and outer ring plates. This minimizes the gap between the outer ring plate and the plastic housing, increasing the flow cross-sectional area. It also minimizes the gap between the outer and inner ring plates and the heating element to reduce the overall pump size. Even if the heating element touches the outer ring plate due to manufacturing defects, the aluminum outer and inner ring plates will not deform due to overheating. The separators that separate the annular flow channel within the housing are not watertight, allowing the annular flow channel to be seamlessly integrated into the housing for liquid communication. The entire housing is filled with liquid, preventing direct heat transfer to the inner wall of the housing by the high-temperature heating element. This avoids overheating of the control components at the rear of the housing and the motor surrounding the housing. Furthermore, no complex sealing structure is required between the annular flow channel and the housing, resulting in a simple and low-cost design.

[0009] Since the inner ring plate and the outer ring plate are each split into two parts and formed separately in the annular guide and the base, and then assembled and spliced ​​together, it is beneficial to simplify the casting process of the annular guide.

[0010] A further design involves installing a second baffle (i.e., a second partition) between the inner ring plate and the inner circumference of the cavity. This second baffle extends spirally around the outer circumference of the motor along the outlet of the volute towards the downstream annular flow channel inlet. The second baffle separates the space between the inner ring plate and the inner circumference of the cavity into a transition channel and a water storage space. The transition channel connects the volute and the annular flow channel. Because the second baffle spirals around the outer circumference of the motor, the cross-sectional height and flow area of ​​the transition channel gradually increase, making it easier for bubbles generated by the impeller's agitation and bubbles drawn in from the suction inlet to flow downstream and be pumped out. Furthermore, the smooth water flow in the transition channel reduces flow resistance and improves pump efficiency.

[0011] Further optimization design is that the second partition is integrally formed with the motor stator housing, making it easy to align the motor stator with the annular guide and base during assembly. Attached Figure Description

[0012] Figure 1 This is an exploded structural diagram of the centrifugal pump according to Embodiment 1 of this utility model;

[0013] Figure 2 yes Figure 1 A three-dimensional schematic diagram of a centrifugal pump;

[0014] Figure 3 yes Figure 1 A three-dimensional schematic diagram of a centrifugal pump after the pump cover and impeller rotor assembly have been removed;

[0015] Figure 4 yes Figure 2 Axial sectional view of cutting plane A (showing the opening of the heating element and the first partition, corresponding to...) Figure 6 , Figure 7 (AA rotated sectional view);

[0016] Figure 5 yes Figure 2 Axial main section view of cutting plane B (corresponding) Figure 6 , Figure 7 (BB rotated sectional view);

[0017] Figure 6 yes Figure 1 A top view of a centrifugal pump (with the pump cover removed, showing the direction of liquid flow);

[0018] Figure 7 yes Figure 1 A top sectional view of a centrifugal pump (cut along the upper end of the heating element to show the direction of liquid flow);

[0019] Figure 8 yes Figure 1 Front view schematic diagram of the heating element of a centrifugal pump;

[0020] Figure 9 yes Figure 8 Top view of the heating element;

[0021] Figure 10 yes Figure 8 3D schematic diagram of an electric heating element;

[0022] Figure 11 yes Figure 8 A three-dimensional diagram of the heating element from another angle;

[0023] Figure 12 yes Figure 1 A three-dimensional schematic diagram of the centrifugal pump base;

[0024] Figure 13 yes Figure 1 A three-dimensional schematic diagram of the annular guide vane of a centrifugal pump;

[0025] Figure 14 yes Figure 13 A bottom view of the annular air guide component;

[0026] Figure 15 yes Figure 13 A three-dimensional schematic diagram of the annular guide from another angle;

[0027] Figure 16 yes Figure 1 A three-dimensional schematic diagram of the pump casing of a centrifugal pump;

[0028] Figure 17 yes Figure 1 A three-dimensional schematic diagram of the motor of a centrifugal pump (including the impeller);

[0029] Figure 18 yes Figure 17 Rear view of the electric motor (showing the direction of fluid flow in the transition channel);

[0030] Figure 19 yes Figure 17 Top view of the electric motor;

[0031] Figure 20 yes Figure 17 Main view of the electric motor (showing the direction of fluid flow in the transition channel);

[0032] Figure 21 This is an exploded structural diagram of the centrifugal pump according to Embodiment 2 of this utility model;

[0033] Figure 22 yes Figure 21 Front view schematic diagram of the heating element of a centrifugal pump;

[0034] Figure 23 yes Figure 22 Top view of the heating element;

[0035] Figure 24 yes Figure 22 A 3D schematic diagram of an electric heating element;

[0036] Figure 25 yes Figure 22 A three-dimensional diagram of the heating element from another angle;

[0037] Figure 26 yes Figure 21 A three-dimensional schematic diagram of the centrifugal pump base;

[0038] Figure 27 yes Figure 20 A bottom view of the annular guide vane of a centrifugal pump;

[0039] Figure 28 yes Figure 27 Top view of the annular guide vane;

[0040] Figure 29 yes Figure 27 A three-dimensional schematic diagram of the annular flow guide;

[0041] Figure 30 yes Figure 27 A three-dimensional schematic diagram of the annular guide from another angle;

[0042] Figure 31 yes Figure 21 A three-dimensional schematic diagram of the motor of a centrifugal pump (including the impeller);

[0043] Figure 32 yes Figure 31 Top view of the electric motor.

[0044] Figure label:

[0045] Pump cover 100, pump cover housing 110, base 200, through hole 201, stator assembly 300, stator housing (motor housing) 310, electric heating tube 400, heating body 411, opening 412, first external part 413, second external part 414, annular guide 500.

[0046] 1. Spool chamber; 2. Cavity; 3. Annular flow channel; 4. Transition flow channel; 5. Water storage space; 6. Inlet; 7. Outlet.

[0047] Inner ring plate 10, first inner ring plate 11, second inner ring plate 12;

[0048] Outer ring plate 20, first outer ring plate 21, second outer ring plate 22;

[0049] Upper ring plate 30;

[0050] First partition 40;

[0051] Second partition (second partition plate) 50. Detailed Implementation

[0052] This utility model embodiment is a further improvement of the prior applications CN114060288B and CN202411051367.6 by the inventors of this application. The main design change is that the cylindrical thick-film heater or the casting enclosing the heating element body inside the annular cavity surrounding the outer circumference of the motor cylinder is replaced with the heating element itself, and the heating element body is immersed in the pump liquid inside the cavity. The pump cover described in CN114060288B and CN202411051367.6 is equivalent to the pump cover 100 described in this utility model embodiment, and the pump body described in CN114060288B is equivalent to the base 200 described in this utility model embodiment. The technical solutions in the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this utility model, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without creative effort are within the scope of protection of this utility model.

[0053] The terms "center," "inner," and "outer" used in the text are based on Figure 5 The indicated orientation or positional relationship refers to the pump shaft axis as the center; "up" and "down" orientations, such as... Figure 5 As shown, the direction of the inlet is "up" and the opposite direction is "down". Upstream specifically refers to the part of the flow channel near the source, and there is no strict boundary between it and the source and the midstream; downstream specifically refers to the part of the flow channel near the outlet, and there is no strict boundary between it and the midstream and the outlet. See the 2000 edition of "Cihai" published by Shanghai Lexicographical Publishing House.

[0054] Example 1

[0055] like Figure 1-20 The centrifugal pump with electric heating function includes: a cover-shaped housing—pump cover 100, a cylindrical pump cover shell 110 formed with a pump cover and protruding from the outer edge of the pump cover, and a cover-shaped opening; a base 200 with a through hole 201; an electric motor, whose axially driven impeller drives the pump liquid in the volute 1; a cavity surrounding the outer periphery of the motor cylinder, the cavity being an annular shape along the axial direction of the motor, formed by the pump cover 100 located at both ends of the motor and the base 200 connected by a stator shell 310 (i.e., the motor shell); an electric heating tube 400 with a heating body 411 built into the cavity 2 of the cavity, the heating body 411 being an annular shape with an opening 412, and a first external part 413 and a second external part 414 extending in the same direction along the vertical direction of the annular shape on both sides of the opening, which are connected to the two ends of the heating body 411. The two external parts are sealed through and extend out of the through hole 201 of the base 200 at the rear end of the cavity for connecting to a power source to heat the pump liquid in the cavity.

[0056] The centrifugal pump also includes a cast aluminum annular guide 500 built into the cavity. The annular guide is integrally formed with a first inner ring plate 11, a first outer ring plate 21, an upper ring plate 30, and a first partition 40. The base 200 is integrally cast with a second inner ring plate 12 and a second outer ring plate 22 from aluminum into the cavity. After the base 200, the heating element 400, and the annular guide 500 are assembled, the first outer ring plate 21 and the second outer ring plate 22 are combined to form an annular outer ring plate 20, which is located axially between the heating element heating body 411 and the outer periphery of the cavity. There is a gap between the outer ring plate 20 and the heating element heating body 411. The first inner ring plate 11 and the second inner ring plate 12 are combined to form an annular inner ring plate 10, which is located axially between the heating element heating body 411 and the cavity. Between the inner circumferences of the body, there is a gap between the inner ring plate 10 and the heating element body 411. The upper ring plate 30 is generally annular and located between the heating element body 411 and the upper end of the cavity along a direction perpendicular to the axial direction. There is a gap between the upper ring plate 30 and the heating element body 411. The inner ring plate 10, outer ring plate 20, upper ring plate 30, base 200 and first partition 40 surround the heating element body 411 to form an annular flow channel 3. The first partition 40 is inserted into the opening 412 of the heating element body 411. The first partition 40 is connected to the inner ring plate 10 inward and to the outer ring plate 20 outward. The annular flow channel 3 communicates with the volute 1 through the inner side of the first partition 40 and with the discharge port 7 of the electric pump through the outer side of the first partition 40. In this way, the annular flow channel 3 is built into the cavity without sealing, and both the cavity 2 of the cavity and the annular flow channel 3 can be filled with pump liquid. The stator housing 310 is integrally formed with a second partition 50. After assembly, the second partition 50 extends in a spiral shape around the stator housing 310 along the outlet of the volute chamber, extending towards the inlet of the downstream annular flow channel 3 at an angle α of more than 180°. This separates the space between the inner ring plate 10 and the stator housing 310 (i.e., the inner periphery of the cavity) into a roughly spiral-shaped transition flow channel 4 and a water storage space 5. The transition flow channel 4 connects the volute chamber 1 and the annular flow channel 3.

[0057] In this way, the cavity 2 of the annular cavity surrounding the outer periphery of the motor cylinder of the centrifugal pump houses an electric heating tube for heating the pump liquid. The heating body 411 of the electric heating tube is generally annular. An annular flow channel 3 is set in the cavity around the heating body 411 of the electric heating tube. The upstream liquid flow is connected to the pump volute 1 through a spiral transition flow channel 4. After being heated by the electric heating tube, the downstream liquid flow is connected to the pump outlet 7 and pumped out. This avoids the heating body 411 of the electric heating tube from touching the stator shell 310, which would cause the stator temperature to rise too high, and also avoids the heating body 411 of the electric heating tube from touching the outer shell of the cavity, i.e., the plastic pump cover shell 110, which would cause it to overheat, deform, or even melt. On the one hand, compared with the existing technology that uses a thick-film cylindrical heater to separate the cavity to form an inner and outer circumferential flow channel, it is more stable in operation and has stronger resistance to dry burning. On the other hand, compared with the existing technology that uses cast aluminum to wrap the heating tube and cast the isolation part to separate the cavity to form an inner and outer circumferential flow channel, it is lighter in weight, smaller in size, and has lower manufacturing cost. Furthermore, compared with the existing inner and outer circumferential flow channels where there is a water flow reversal, the annular flow channel has a smooth water flow, which reduces the flow channel resistance and improves the pump efficiency.

[0058] The outer shell of the cavity, i.e. the pump housing, is made of low-cost plastic, while the inner and outer ring plates are made of metal with high precision and are not easily deformed. This minimizes the gap between the outer ring plate and the plastic outer shell of the cavity, expanding the flow cross-sectional area of ​​the flow channel. It also minimizes the gap between the outer and inner ring plates and the heating element to reduce the overall size of the pump. Even if the heating element touches the outer ring plate due to manufacturing deviations, the aluminum outer ring plate will not deform due to overheating. The partition components that separate the annular flow channel from the cavity are not watertight, allowing the annular flow channel to be built into the cavity without sealing, thus achieving liquid communication. The entire cavity is filled with liquid, and the high-temperature heating element of the heating element will not directly contact the inner wall of the cavity, preventing overheating of the control components at the rear end of the cavity and the motor surrounding the cavity. Moreover, there is no need for a complex sealing structure between the annular flow channel and the cavity, resulting in a simple structure and low cost.

[0059] The inner ring plate and the outer ring plate are each split into two parts, which are formed on the annular guide and the base respectively. They are then assembled and put together, which helps to simplify the casting process of the annular guide.

[0060] Because the second baffle spirals around the outer periphery of the motor, the cross-sectional height of the transition channel that separates the volute and the annular flow channel gradually increases, and the flow cross-sectional area gradually increases. This makes it easier for the bubbles generated by the impeller and the bubbles sucked in by the suction port to flow downstream along the gentle flow channel and be pumped out. Moreover, the gentle flow of water in the transition channel reduces the flow resistance and improves the efficiency of the pump.

[0061] Example 2:

[0062] like Figure 21-32The centrifugal pump in this embodiment differs from the centrifugal pump in Embodiment 1 in that the molding processes of the inner ring plate, outer ring plate, and second partition plate separating the transition flow channel are different. Furthermore, the first external portion 413 and the second external portion 414 of the heating tube, which extend in the same direction perpendicular to the heating body of the annular heating tube, are not located on opposite sides of the opening 412 of the heating body 411, but on the same side, which helps reduce the number of terminals and lower costs. The cast aluminum annular guide component 500 is integrally molded as an outer ring plate 20, inner ring plate 10, upper ring plate 30, first partition 40, and second partition plate 50. The second inner ring plate and second outer ring plate are not cast on the base, nor is the second partition plate formed on the stator shell. This simplifies the molding of the motor stator shell and base, and facilitates the alignment of the annular guide component, base, and motor stator during assembly.

[0063] This utility model is not limited to the above-described embodiments. If any modifications or variations to this utility model do not depart from the spirit and scope of this utility model, and if such modifications and variations fall within the scope of the claims and equivalent technologies of this utility model, then this utility model also intends to include such modifications and variations.

Claims

1. A centrifugal pump with an electric heating function, comprising: —The electric motor, whose axially driven impeller drives the pump liquid in the volute (1); —A cylindrical cavity that encircles the outer periphery of the motor cylinder; —The heating element (400) has a heating body (411) built into the cavity (2) of the cavity to heat the pump liquid. The heating body is generally annular with an opening (412), and a first external part (413) and a second external part (414) extending in the same direction along the vertical direction of the opening and connected to both ends of the heating body (411). Its characteristic is that it also includes: —Inner ring plate (10), the inner ring plate is generally annular, and the inner ring plate is located between the heating body (411) and the inner circumference of the cavity along the axial direction; —Outer ring plate (20), the outer ring plate is generally annular, and the outer ring plate is located between the heating body (411) and the outer periphery of the cavity along the axial direction; — Upper ring plate (30), the upper ring plate is generally ring-shaped, and the upper ring plate is located between the heating body (411) and the upper end of the cavity along an orientation perpendicular to the axis; —There is a gap between the inner ring plate (10), the outer ring plate (20), the upper ring plate (30) and the heating body (411); —First partition (40), the first partition is provided at the opening (412) of the heating body (411), and is connected to the inner ring plate (10) inward and to the outer ring plate (20) inward; —The first external portion (413) and the second external portion (414) of the heating element (400) are sealed and pass through and extend out of the rear end of the cavity for connection to the power supply; —The inner ring plate (10), outer ring plate (20), upper ring plate (30), rear end of the cavity and first partition (40) surround the heating body (411) to form an annular flow channel (3). The annular flow channel communicates with the volute (1) through the inner side of the first partition (40) and with the discharge port of the electric pump through the outer side of the first partition (40).

2. The centrifugal pump with electrothermal function as described in claim 1, characterized in that: —The outer ring plate (20) is split into a first outer ring plate (21) and a second outer ring plate (22), and the inner ring plate (10) is split into a first inner ring plate (11) and a second inner ring plate (12); —It also includes a metal annular guide (500) built into the cavity, the annular guide (500) being integrally formed with the first inner ring plate (11), the first outer ring plate (21), the upper ring plate (30), and the first partition (40); —The rear end of the cavity is surrounded by a metal base (200). The base is provided with a through hole (201) through which the first external part (413) and the second external part (414) of the power supply heat pipe (400) pass. The base (200) integrally forms the second inner ring plate (12) and the second outer ring plate (22) into the cavity. —After the base (200), heating tube (400), and annular guide (500) are assembled, the first outer ring plate (21) and the second outer ring plate (22) are combined to form the outer ring plate (20), and the first inner ring plate (11) and the second inner ring plate (12) are combined to form the inner ring plate (10); —The annular flow channel (3) is unsealed and built into the cavity (2) of the cavity.

3. The centrifugal pump with electrothermal function as described in claim 1, characterized in that: A second partition is provided between the inner ring plate (10) and the inner periphery of the cavity. The second partition extends in a spiral shape around the outer periphery of the motor along the outlet of the volute (1) and toward the inlet of the downstream annular flow channel (3). The second partition separates the space between the inner ring plate (10) and the inner periphery of the cavity into a transition flow channel (4). The transition flow channel (4) is used to connect the volute (1) and the annular flow channel (3).

4. The centrifugal pump with electrothermal function as described in claim 3, characterized in that: The second partition is a second partition (50) integrally formed with the motor housing. The second partition (50) separates the space between the inner ring plate (10) and the inner periphery of the cavity into a transition channel (4) and a water storage space (5).

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