Electric centrifugal fluid pump

Abstract

The invention relates to an electric centrifugal fluid pump (10) having a pump wheel (20) rotating about a vertical rotation axis (R), an electric drive motor (30) driving the pump wheel (20), and a pump housing (100) accommodating the pump wheel (20) and the electric drive motor (30), wherein the pump housing (100) comprises a pump chamber housing (110) having a pump chamber wall (110') defining a pump chamber (119), wherein the pump wheel (20) rotates in the pump chamber (119), a radial-axial fluid inlet passage (120) having a pump inlet opening flange (122) surrounding a pump inlet opening (12), and a tangential-radial outlet passage (130) having a pump outlet opening flange (132) surrounding a pump outlet opening (14), while the pump inlet opening flange (122) and the pump outlet opening flange (132) have a single linear fluid mounting axis (M), wherein the fluid mounting axis (M) is inclined with respect to the horizontal plane (xy) by a mounting axis angle (a) of at least 4°, and wherein the tangential-radial outlet passage (130) is located in a horizontal plane (xy) perpendicular with respect to the rotation axis (R).

Description

[0001] This invention relates to an electric centrifugal fluid pump, and more preferably to a circulating pump for heating and / or cooling liquid circuits in buildings.

[0002] A typical electric centrifugal fluid pump is a circulating pump used in a heated liquid circuit. It has a fluid inlet passage that is in-line with the fluid outlet passage, and both the fluid inlet and outlet passages are defined by a pumping chamber housing. The pumping chamber housing also defines a pumping chamber in which the pump impeller rotates.

[0003] Typically, for fluid flow pumps with centrifugal impellers, the pump chamber inlet opening is axially oriented and the pump chamber outlet opening is tangentially oriented, such that the pump chamber inlet and outlet openings are generally not straight relative to each other. DE68 910 574 D1 discloses a typical centrifugal fluid pump for a fixed heated liquid circuit, wherein the centrifugal fluid pump is provided with pump inlet and outlet openings that are linearly straight relative to each other, facilitating installation of the fluid pump in a linear section of the heated circuit. The orientation of the pump inlet and outlet openings is precisely rectangular relative to the axis of rotation of the impeller. The inlet passage between the pump inlet and pump chamber inlet openings, and the outlet passage between the pump chamber outlet opening and the pump outlet opening, both include several curves to provide a linear mounting axis for the pump but introduce considerable fluid resistance.

[0004] GB 681 295 A and US 2 851 955 A disclose fluid flow pumps having inlet and outlet channels arranged not perpendicular to the pump impeller's axis of rotation to reduce overall fluid resistance. However, the fluid resistance in the outlet channel remains relatively high because the inclination of the outlet channel relative to the transverse plane of the volute results in considerable flow resistance, where the fluid exiting the volute exhibits considerable turbulence.

[0005] The purpose of this invention is to provide a linear electro-fluid pump with minimal flow resistance.

[0006] This objective is achieved according to the invention by an electric centrifugal fluid pump having the features of claim 1.

[0007] An electric centrifugal fluid pump is a flow-type pump equipped with a pump impeller, such as a pump wheel, that rotates about an axial / vertical axis of rotation. The fluid pump is equipped with an electric drive motor that directly drives the pump impeller. The fluid pump is provided with a pump housing that houses the pump impeller and the electric drive motor. The pump housing includes a separate pump chamber housing with pump chamber walls defining the pump chamber, within which the pump impeller rotates and the pumped fluid is accelerated in both radial and tangential directions.

[0008] The pump housing defines a radial-axial fluid inlet passage with a pump inlet flange surrounding the pump inlet opening, and a tangential-radial outlet passage with a pump outlet flange surrounding the pump outlet opening. The pump inlet and outlet flanges are geometrically linearly aligned with each other, thus defining a single linear fluid mounting axis. The electric centrifugal fluid pump can be easily integrated into a linear fluid line by simply replacing the linear portion of the fluid line with an electric centrifugal fluid pump.

[0009] The fluid mounting axis is inclined at an angle of at least 4° relative to the horizontal plane. This inclination reduces the maximum curvature of the inlet passage between the pump inlet opening and the pump chamber inlet opening to a maximum of 86°, thereby reducing the fluid resistance of this part of the pump.

[0010] The tangential-radial outlet channel is located in a horizontal plane perfectly perpendicular to the vertical axis of rotation, allowing for a smooth transition of fluid leaving the volute from the volute to the outlet channel. Therefore, fluid resistance in this part of the pump is minimized. Consequently, the overall fluid resistance of the electric centrifugal fluid pump is optimized.

[0011] Preferably, the mounting axis of the pump outlet flange is inclined at a mounting axis angle relative to the tangential-radial outlet loop located in the horizontal plane. By angulating the pump outlet flange relative to the horizontal outlet channel, a single linear mounting axis is achieved for both the pump inlet and outlet flanges, while simultaneously reducing the pump's overall fluid resistance.

[0012] Preferably, the radial portion of the radial-axial fluid inlet passage is inclined at the mounting axis angle, such that the radial portion of the fluid inlet passage substantially defines the linear fluid mounting axis of the fluid pump.

[0013] Preferably, the pump chamber housing is provided with a plurality of axial reinforcing ribs, which extend distally from the pump chamber wall in the axial direction. Preferably, the pump chamber housing is made of plastic. The axial reinforcing ribs provide the pump chamber housing with sufficient rigidity for the high static pressure characteristic of circulating pumps in the heated liquid circuit of a building.

[0014] Preferably, the pump chamber housing has two sections: an outlet section that includes and defines a fluid outlet passage and an inlet section that includes and defines a fluid inlet passage. The outlet section of the pump chamber housing is provided with several, i.e., at least two, radially oriented reinforcing ribs extending radially relative to the axial axis of rotation of the pump rotor. The inlet section of the pump chamber housing is provided with several transverse reinforcing ribs parallel to each other and arranged substantially orthogonal to a linear mounting axis defined by the inlet and outlet flanges. Preferably, each of the outlet and inlet sections defines substantially half the circumference of the pump chamber.

[0015] The outlet section with radial reinforcing ribs allows only axial-vertical deformation, while the inlet section with transverse parallel reinforcing ribs allows for horizontal or axial-vertical deformation. Therefore, axial downcutting at the pump chamber housing body is possible, providing greater freedom in the pump chamber housing construction. In particular, the increased construction freedom allows the fluid mounting axis to be tilted a few degrees relative to the horizontal plane of the pump chamber housing, which can significantly reduce fluid resistance throughout the fluid path of the pump.

[0016] The radial portion of the radial-axial fluid inlet channel has an angle greater than 94° relative to the horizontal plane of the axial inlet opening of the pump impeller, such that the incoming fluid is deflected less than 86° between the pump housing inlet opening and the pump impeller inlet opening.

[0017] Preferably, the radial reinforcing ribs of the outlet section are arranged in a star shape relative to the axis of rotation.

[0018] The pump chamber wall defines a volute surrounding the pump impeller, the cross-section of which gradually increases in the downstream direction of the volute, reaching its maximum cross-section at the end of the fluid volute, which is the starting point of the tangential portion of the tangential-radial outlet channel.

[0019] Preferably, the pump chamber housing defines a pump chamber housing mounting flange located in a horizontal plane relative to the vertical axis of rotation of the pump impeller. The pump chamber housing mounting flange serves as the mechanical interface between the pump chamber housing and the motor housing. At least 50%, more preferably all, of the reinforcing ribs extend to the outer diameter of the mounting flange.

[0020] Preferably, the pump housing defines at least two mounting bodies, each defining an axial mounting hole for mounting and securing the pump housing to the motor housing via bolts, screws, or other axial fastening devices. The mounting bodies must withstand high axial holding forces caused by internal fluid pressures up to 25 bar. Reinforcing ribs extend to each mounting body, providing strong mechanical support.

[0021] Preferably, two fixing bodies are located at the outlet section and two fixing bodies are located at the inlet section of the pump chamber housing. More preferably, these fixing bodies are equidistantly arranged at the mounting flanges at an angle (e.g., 90°) to each other.

[0022] Preferably, the reinforcing ribs have an axial extension of at least 5 mm. Preferably, at least five radial reinforcing ribs are provided.

[0023] One embodiment of the present invention is described with reference to the accompanying drawings, wherein... Figure 1 A side view of an electric centrifugal fluid pump with a pump housing including a pump chamber is shown. Figure 2 It shows Figure 1A top view of the pump chamber casing of a fluid pump. Figure 3 It shows Figure 1 and Figure 2 A perspective view of the pump chamber casing, and Figure 4 Showing Figures 1 to 3 Bottom view of the pump chamber casing.

[0024] Figure 1 and Figure 3 An electric centrifugal fluid pump 10 is shown, which is suitable for use as a circulating pump for pumping heated liquids, such as water, in a heated liquid circuit of a building with several floors. Typically, the heating circulating pump is located at a vertically low position in the heating circuit, such that the static gravity pressure in the fluid pump 10 is typically in the range of 10 to 20 bar.

[0025] The fluid pump 10 is provided with a pump housing 100, which includes a separate plastic pump chamber housing 110 and a separate motor housing 190. The motor housing 190 encloses an electric drive motor 30 having an electromagnetic motor stator 32 and a permanent magnetized motor rotor 34. The electric drive motor 30 is designed as a hermetically sealed motor.

[0026] The plastic pump chamber housing 110 is made of a single-fiber reinforced plastic body and internally houses a centrifugal pump impeller 20, which is designed as a actuator with a central axial inlet opening and an annular radial outlet opening. The rotor, including the pump rotor 20 and a co-rotating motor rotor 34, rotates about a rotation axis R with a vertical orientation z.

[0027] The pump chamber housing 110 has a pump chamber wall 110' surrounding a pump chamber 119, which includes an outlet volute 90. The pump impeller 20 rotates within the pump chamber 119 and is radially surrounded by the outlet volute 90. The outlet volute 90 has an increased cross-section in the upstream direction.

[0028] The pump housing 110 also defines a radial-axial fluid inlet passage 120 with an inlet flange 122 and a tangential-radial outlet passage 130 with an outlet flange 132. The inlet flange 122 surrounds the pump inlet opening 12, and the outlet flange 132 surrounds the pump outlet opening 14. The inlet flange 122 and the outlet flange 132 are geometrically perfectly aligned with each other at the linear fluid mounting axis M. The fluid mounting axis M is inclined at an angle of approximately 15° relative to the horizontal plane xy.

[0029] The tangential-radial outlet passage 130 is located in a horizontal plane xy130 perpendicular to the vertical axis of rotation R. The mounting axis M of the pump outlet flange 132 is inclined at an angle α relative to the horizontal plane xy130 of the tangential-radial outlet passage 130. The radial portion 120R of the radial-axial fluid inlet passage 120 is inclined at an angle α relative to the horizontal plane xy130 of the tangential-radial outlet passage 130.

[0030] The pump chamber housing 110 is provided with a number of axial reinforcing ribs 51-58, 61-66, which extend distally from the pump chamber wall 110' in the axial direction z. Referring to the orientation of the reinforcing ribs 51-58, 61-66, the pump chamber housing 110 is divided into two sections: an outlet section 111 including a complete fluid outlet passage 130, and an inlet section 112 including a fluid inlet passage 120. A virtual vertical plane separating the outlet section 111 and the inlet section 112 includes a rotation axis R and is oriented perpendicular to the fluid mounting axis M. In the inlet section 112, six axially extending reinforcing ribs 61 to 66 located on both sides of the inlet passage 120 are perpendicular to the transverse reinforcing ribs 61 to 66, parallel to each other and arranged perpendicularly to the mounting axis M in the transverse vertical plane yz. In the outlet section 111, the seven reinforcing ribs are radial reinforcing ribs 51-58, which are not oriented in the transverse vertical plane yz, that is, not perpendicular to the mounting axis M, but radially oriented relative to the rotation axis R, and together define the star-shaped rib structure.

[0031] Pump chamber housing 110 defines an axial pump chamber inlet opening 92 in a horizontal plane xy, and also defines an annular pump chamber housing mounting flange 140 in another horizontal plane xy. Four block-shaped fixing bodies 81-84 are provided radially outside the annular portion of the mounting flange 140, each defining an axial fixing hole 85. The pump chamber housing fixing bodies 81-84 correspond vertically to four fixing bodies 81', 82' at the motor housing 190. The motor housing 190 and pump chamber housing 110 are held together by four screws 88 extending through the motor housing fixing bodies 81', 82' and screwed into the pump chamber housing mounting bodies 81-84.

[0032] like Figure 2 As shown, the corresponding reinforcing ribs 53, 57, 63, and 66 extend radially to each of the four fixed bodies 81-84, such that the fixed bodies 81-84 are axially supported by the corresponding reinforcing ribs 53, 57, 63, and 66. All reinforcing ribs 51-66 extend radially to the outer diameter of the pump chamber housing mounting flange 140. The axial extension of the reinforcing ribs 51-66 is at least 5 mm.

[0033] The pump chamber housing 110 is provided with three circumferential annular reinforcing ribs 71, 72, and 73, which are located in horizontal planes xy that are parallel to each other, and substantially surround and reinforce the circumferential pump chamber wall 110' that defines the volute 90.

[0034] In the current context, the terms “horizontal” and “vertical” do not usually refer to the land plane, but rather to the axis of rotation R, which is defined as the vertical axis in this paper.

Claims

1. An electric centrifugal fluid pump (10) having a pump wheel (20) that rotates about a vertical axis of rotation (R), an electric drive motor (30) that drives the pump wheel (20), and a pump housing (100) that houses the pump wheel (20) and the electric drive motor (30). The pump housing (100) includes a pump chamber housing (110), the pump chamber housing (110) having The pump chamber wall (110') defines the pump chamber (119), wherein the pump impeller (20) rotates within the pump chamber (119). A radial-axial fluid inlet passage (120) having a pump inlet opening flange (122) surrounding the pump inlet opening (12), and A tangential-radial outlet passage (130) having a pump outlet opening flange (132) surrounding the pump outlet opening (14). The pump inlet flange (122) and the pump outlet flange (132) have a single linear fluid mounting axis (M). The fluid mounting axis (M) is inclined relative to the horizontal plane (xy) at a mounting axis angle (a) of at least 4°, and The tangential-radial outlet channel (130) is located in a horizontal plane (xy130) that is perpendicular to the axis of rotation (R).

2. The electric centrifugal fluid pump (10) according to claim 1, wherein, The mounting axis (M) of the pump outlet flange (132) is inclined relative to the tangential-radial outlet channel (130) at the mounting axis angle (a).

3. The electric centrifugal fluid pump (10) according to any one of the preceding claims, wherein, The radial portion (120R) of the radial-axial fluid inlet channel (120) is inclined at the mounting axis angle (a).

4. The electric centrifugal fluid pump (10) according to any one of the preceding claims, wherein, The pump chamber housing (110) is provided with a number of axial reinforcing ribs (51-58, 61-66), which extend distally from the pump chamber wall (110') along the axial direction (z).

5. The electric centrifugal fluid pump (10) according to any one of the preceding claims, wherein, The outlet section (111) of the pump chamber housing (110), which includes the fluid outlet channel (130), is provided with a plurality of radial reinforcing ribs (51-58), and the inlet section (112) of the pump chamber housing (110), which includes the fluid inlet channel (120), is provided with a plurality of transverse parallel reinforcing ribs (61-66), which are arranged substantially orthogonally to the mounting axis (M).

6. The electric centrifugal fluid pump (10) according to claim 5, wherein, The radial reinforcing ribs (51-58) are arranged in a star shape relative to the axis of rotation (R).

7. The electric centrifugal fluid pump (10) according to any one of claims 5 or 6, wherein, The pump chamber housing (110) defines a pump chamber housing mounting flange (140) located in a horizontal plane (xy), and at least 50% of the reinforcing ribs (51-58, 61-66) extend to the outer diameter of the pump chamber housing mounting flange (140).

8. The electric centrifugal fluid pump (10) according to any one of claims 4 to 7, wherein, The pump chamber housing (110) defines at least two fixing bodies (81-84), each fixing body defining an axial fixing hole (85), and the reinforcing ribs (53, 63, 66, 56) extend axially to the fixing bodies (81-84), respectively.

9. The electric centrifugal fluid pump (10) according to claim 8, wherein, At least four fixing bodies (81-84) are provided, with two fixing bodies (81, 84) provided at the outlet section (111) and two fixing bodies (82, 83) provided at the inlet section (112) of the pump chamber housing (110).

10. The electric centrifugal fluid pump (10) according to any one of claims 5 to 9, wherein the minimum axial extension length of the reinforcing ribs (51-58, 61-66) is 5 mm.

11. The electric centrifugal fluid pump (10) according to any one of claims 6 to 10, wherein, It is provided with at least five radial reinforcing ribs (51-58).

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