A low-noise semi-spiral water suction chamber design method

Abstract

This invention belongs to the field of double-suction pump technology, and specifically relates to a low-noise semi-spiral suction chamber design method. It includes a pump casing, within which a semi-spiral suction chamber and an impeller are disposed. A sealing body is provided between the pump casing and the impeller shaft, located on the outer side of the semi-spiral suction chamber away from the impeller. An inserting baffle is provided on the sealing body. The semi-spiral suction chamber includes a cross-section 'a' with an angle θ of 0 and n cross-sections, with cross-sectional areas ranging from S... a To S n The number of cross-sections increases sequentially, with n being an integer. The formula for calculating n is the cross-sectional area S. n The formula for calculating the cross-sectional area S when n≥2 is: n‑1 The calculation formula is S n‑1 =k s S n When θ < 90°, the outlet of the semi-spiral suction chamber has a symmetrical structure about section a, and section a is a vertical plane. The pump casing of this invention does not require an inward concavity, resulting in lower casting difficulty and cost. Furthermore, the number and placement of the baffles are more flexible, allowing for adjustments based on the actual circulation position.

Description

Technical Field

[0001] This invention belongs to the field of dual-suction pump technology, and specifically relates to a low-noise semi-spiral suction chamber design method. Background Technology

[0002] The semi-spiral suction chamber is a common suction chamber shape, mainly used in single-stage double-suction pumps or multi-stage double-suction pumps. It can ensure that the fluid at the impeller inlet has a uniform velocity field, a relatively uniform flow velocity distribution, and low flow loss.

[0003] The semi-spiral suction chamber is designed to accommodate the different flow directions of the pump and the impeller inlet. Its annular inlet inevitably generates circulation, and the fluid has already pre-swirled before entering the impeller. Therefore, the pump head will be lower than the design head.

[0004] Existing methods typically suppress circulation by minimizing the cross-section. For example, Chinese invention patent CN1029666001B discloses a hydraulic design method for a semi-spiral suction chamber for pumps, which provides the main geometric parameters of the semi-spiral suction chamber, including the baffle angle α, the baffle included angle γ, the upper radius R1 of the suction chamber, the baffle inlet and outlet radii r1, the base circle radius R2, the lower radius R3 of the suction chamber, the baffle length l, the baffle included angle θ, the baffle thickness δ, the inlet radius b3 of the eight sections, the inclination angle ω of the eight sections, and the radius R of each section. i The horizontal length of each cross-section is l i and the height h of each section i The concave design within the pump casing forms a tongue, suppressing circulation.

[0005] The shortcomings of the above-mentioned semi-spiral suction chamber for pumps are: the tongue is formed by the concave pump casing, which makes the pump casing difficult to cast and costly, and the position of the tongue is not easy to adjust, so the tongue cannot be set according to the actual circulation position. Summary of the Invention

[0006] The purpose of this invention is to provide a low-noise semi-spiral suction chamber design method, which eliminates the need for an inwardly recessed pump casing, reduces the difficulty and cost of pump casing casting, and allows for greater flexibility in the number and placement of baffles, enabling the baffles to be set according to the actual circulation position.

[0007] The objective of this invention is achieved as follows:

[0008] A low-noise semi-spiral suction chamber design method includes a pump casing, within which a semi-spiral suction chamber and an impeller are disposed. A sealing body is provided between the pump casing and the impeller shaft, the sealing body being located on the outer side of the semi-spiral suction chamber away from the impeller. A baffle plate extending into the semi-spiral suction chamber is provided on the sealing body. The semi-spiral suction chamber includes a cross-section 'a' with an angle θ of 0 and n cross-sections, the cross-sectional area ranging from S... a To S nThe number of cross-sections increases sequentially, with n being an integer. The formula for calculating n is: in The angle between each section, Cross-sectional area S n The calculation formula is Q d V is the design flow rate of the pump. im The inlet velocity of the impeller; when n≥2, the cross-sectional area S n-1 The calculation formula is S n-1 =k s S n ,in θ is the angle of the cross section; when θ < 90°, the outlet of the semi-spiral water absorption chamber is a symmetrical structure about the cross section a, and the cross section a is a vertical plane.

[0009] In the aforementioned low-noise semi-spiral water intake chamber design method, the formula for calculating the partition height H is H = k m D f D f k is the diameter of the sealing body. m =0.2~0.7Df.

[0010] In the above-mentioned low-noise semi-spiral water absorption chamber design method, one partition is provided and located at section a.

[0011] In the above-mentioned low-noise semi-spiral water absorption chamber design method, there are two or more partitions, one of which is located at section a.

[0012] In the aforementioned low-noise semi-spiral water intake chamber design method, the orientation of the baffle can be towards the center of the circle, or the angle can be adjusted according to the incoming flow.

[0013] In the above-mentioned low-noise semi-spiral water absorption chamber design method, the outer end of the partition is wavy along its width direction.

[0014] In the aforementioned low-noise semi-spiral water absorption chamber design method, the wave-shaped curve is a sine function curve.

[0015] In the above-mentioned low-noise semi-spiral water absorption chamber design method, the inlet of the semi-spiral water absorption chamber consists of three cross sections, and the two cross sections near the outlet of the semi-spiral water absorption chamber have a smooth transition.

[0016] In the above-mentioned low-noise semi-spiral water absorption chamber design method, the diameter of the first section at the inlet of the semi-spiral water absorption chamber is the diameter of the water absorption chamber, which is designed according to the flow rate.

[0017] In the above-mentioned low-noise semi-spiral suction chamber design method, the sealing body includes an annular mounting seat installed on the pump casing and an annular mounting part for installing a baffle. The outer wall of the annular mounting part is a concave arc surface, and the diameter gradually decreases outward from the connection with the annular mounting seat. The outer wall of the annular mounting part and the inner wall are transitioned by a rounded corner. The end of the baffle near the annular mounting seat is provided on the outer wall, the rounded corner, and the outer end of the inner wall.

[0018] In the above-mentioned low-noise semi-spiral water absorption chamber design method, the inner sidewall includes a cylindrical surface and a conical surface, the conical surface is located outside the cylindrical surface, the annular mounting seat is disposed at the outer end of the conical surface, and the diameter of the conical surface gradually increases from the inside to the outside.

[0019] In the above-mentioned low-noise semi-spiral water absorption chamber design method, the structure of the sealing body of the partition can be: the partition and the sealing body are an integral structure.

[0020] In the above-mentioned low-noise semi-spiral water absorption chamber design method, the structure of the sealing body of the partition can also be: the partition is fixedly connected to the sealing body by welding.

[0021] In the above-mentioned low-noise semi-spiral suction chamber design method, the material of the sealing body is the same as that of the pump casing. A sealing device is provided between the sealing body and the rotating shaft. The pump casing includes an upper pump casing and a lower pump casing. The upper pump casing and the lower pump casing form a mounting hole for installing an annular mounting seat. The outer ring of the annular mounting seat is provided with an annular protrusion. The mounting hole is provided with an annular groove that matches the annular protrusion. The sealing body is fixedly installed in the mounting hole through the annular protrusion and the annular groove.

[0022] In the above-mentioned low-noise semi-spiral suction chamber design method, the material of the sealing body is stainless steel or cast iron, the sealing device is a mechanical seal, the outer side of the pump casing is provided with a bearing seat mounted on the sealing body, a bearing is provided between the bearing seat and the rotating shaft, and the end face of the sealing body near the bearing seat is recessed to form an installation groove for installing the mechanical seal end cover.

[0023] In the aforementioned low-noise semi-spiral water intake chamber design method, screws pass through the bearing housing and are threaded to the sealing body, and screws also pass through the mechanical seal end cap and are threaded to the sealing body.

[0024] The outstanding and beneficial technical effects of this invention compared to the prior art are:

[0025] 1. In this invention, the baffles that prevent circumferential flow are set on the sealing body, eliminating the need for an inwardly recessed pump casing. This reduces the difficulty and cost of casting the pump casing, and allows for greater flexibility in the number and placement of the baffles. The baffles can be set according to the actual flow position, which is beneficial for rectifying the flow in the semi-spiral suction chamber, improving the flow pattern within the semi-spiral suction chamber, suppressing impeller inlet pre-selection, and improving the pump's power output, head, and efficiency. Furthermore, the improved flow pattern also improves vibration and noise characteristics. The outlet of the semi-spiral suction chamber in this invention has a symmetrical structure about section a, resulting in more uniform flow within the semi-spiral suction chamber. The symmetrical section a at the outlet of the semi-spiral suction chamber in this invention is a vertical plane, with a small number of sections n, simplifying design, molding, and casting, and facilitating production and processing.

[0026] 2. The outer end of the baffle of the present invention is wavy along its width direction, which reduces the flow resistance of the liquid in the semi-spiral suction chamber and effectively improves the operating efficiency of the pump. Attached Figure Description

[0027] Figure 1 This is a perspective view of the present invention;

[0028] Figure 2 This is a cross-sectional view of the present invention;

[0029] Figure 3 This is a perspective view of the present invention without a sealing body;

[0030] Figure 4 This is a front view of the sealing body and the partition plate of the present invention;

[0031] Figure 5 This is a perspective view of the sealing body and the multiple partitions of the present invention;

[0032] Figure 6 This is a schematic diagram of the semi-spiral vortex suction chamber of the present invention;

[0033] Figure 7 This is a comparison chart of noise levels before and after the improvement.

[0034] Reference numerals: 1. Pump casing; 1a. Upper pump casing; 1b. Lower pump casing; 1c. Mounting hole; 1d. Annular groove; 2. Semi-spiral suction chamber; 3. Impeller; 4. Shaft; 5. Sealing body; 5a. Annular assembly seat; 5b. Annular mounting part; 5c. Outer side wall; 5d. Inner side wall; 5d1. Cylindrical surface; 5d2. Conical surface; 5e. Rounded corner; 5f. Annular flange; 6. Baffle plate. Detailed Implementation

[0035] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. See also: Figure 1 —7:

[0036] A low-noise semi-spiral suction chamber design method includes a pump casing 1, within which a semi-spiral suction chamber 2 and an impeller 3 are disposed. A sealing body 5 is provided between the pump casing 1 and the shaft 4 of the impeller 3. The sealing body 5 is located on the outer side of the semi-spiral suction chamber 2 away from the impeller 3. A baffle 6 extending into the semi-spiral suction chamber 2 is provided on the sealing body 5. The semi-spiral suction chamber 2 includes a section with a cross-sectional angle θ of 0 and n cross-sections, with cross-sectional areas ranging from S... a To S n The number of cross-sections increases sequentially, with n being an integer. The formula for calculating n is: in The angle between each section, Cross-sectional area S n The calculation formula is Q d V is the design flow rate of the pump. im The inlet velocity of impeller 3; when n≥2, the cross-sectional area S n-1 The calculation formula is S n-1 =k s S n ,in θ is the angle of the cross-section; when θ < 90°, the outlet of the semi-spiral water absorption chamber 2 has a symmetrical structure about the cross-section a, i.e., S b’ =S b S c’ =S c S d’ =S d Furthermore, section a is a vertical plane.

[0037] Furthermore, Sa is selected based on the inlet diameter of impeller 3, and the smaller the area of ​​section a, Sa, the better.

[0038] In this embodiment, the number of cross-sections n is 8. It is 22.5°.

[0039]

[0040]

[0041] Sa is selected based on the inlet diameter of impeller 3.

[0042] like Figure 1-6As shown, the baffle 6 that prevents circumferential flow in this invention is set on the sealing body 5, eliminating the need for the pump casing 1 to be recessed. This reduces the difficulty and cost of casting the pump casing 1, and allows for greater flexibility in the number and placement of the baffles 6. The baffles can be set according to the actual flow position, which is beneficial for rectifying the flow within the semi-spiral suction chamber 2, improving the flow pattern within the semi-spiral suction chamber 2, suppressing pre-selection at the impeller 3 inlet, and improving the pump's work output, head, and efficiency. Furthermore, the improved flow pattern also improves vibration and noise characteristics. The outlet of the semi-spiral suction chamber 2 in this invention has a symmetrical structure about section a, resulting in more uniform flow within the semi-spiral suction chamber 2. The symmetrical section a at the outlet of the semi-spiral suction chamber 2 in this invention is a vertical plane, with a small number of sections n, simplifying design, molding, and casting, and facilitating production and processing.

[0043] Partition 6 height H: as Figure 4 As shown, the formula for calculating the height H of the partition 6 is H = k m D f D f k is the diameter of the sealing body 5. m =0.2~0.7Df, without interfering with other parts, the partition 6 has a high height and large area, and has a good effect in preventing the circulation.

[0044] The number of partitions 6 can be: one partition 6 is provided, and it is located at section a, such as... Figure 2 , 4 As shown, the forces on the left and right sides of the partition 6 are relatively balanced, and the fluid flow in the semi-spiral water absorption chamber 2 is uniform.

[0045] The number of partitions 6 can also be: there are two or more partitions 6, one of which is located at section a, such as... Figure 5 As shown.

[0046] Orientation of baffle 6: The baffle 6 can be oriented towards the center of the circle, or its angle can be adjusted according to the incoming flow. In this embodiment, five baffles 6 are provided, and the baffles 6 are oriented parallel to the flow direction.

[0047] In order to reduce the flow resistance of the liquid in the semi-spiral suction chamber 2, the outer end of the baffle 6 is wavy along its width direction, which effectively improves the operating efficiency of the pump.

[0048] Preferably, the wavy curve is a sine function curve.

[0049] Furthermore, the inlet of the semi-spiral water suction chamber 2 consists of three cross-sections, and the two cross-sections near the outlet of the semi-spiral water suction chamber 2 have a smooth transition, i.e. Figure 6 The transition between section 1 and section 2 is smooth.

[0050] Furthermore, the first cross-section at the inlet of the semi-spiral water absorption chamber 2 (i.e. Figure 6 The diameter of section 3) is the diameter of the water absorption chamber, designed according to the flow velocity.

[0051] Structure of sealing body 5: as follows Figure 4 , 5 As shown, the sealing body 5 includes an annular mounting seat 5a mounted on the pump housing 1 and an annular mounting portion 5b for mounting the partition plate 6. The outer wall 5c of the annular mounting portion 5b is a concave arc surface, and its diameter gradually decreases outward from the connection with the annular mounting seat 5a. The outer wall 5c of the annular mounting portion 5b and the inner wall 5d are transitioned by a rounded corner 5e. The end of the partition plate 6 near the annular mounting seat 5a is disposed on the outer wall 5c, the rounded corner 5e, and the outer end of the inner wall 5d.

[0052] Furthermore, the inner sidewall 5d includes a cylindrical surface 5d1 and a conical surface 5d2, the conical surface 5d2 being located outside the cylindrical surface 5d1, the annular mounting seat 5a being disposed at the outer end of the conical surface 5d2, and the diameter of the conical surface 5d2 gradually increasing from the inside to the outside.

[0053] Assembly structure of sealing body 5: as follows Figure 1-5 As shown, the material of the sealing body 5 is the same as that of the pump housing 1. A sealing device is provided between the sealing body 5 and the rotating shaft 4. The pump housing 1 includes an upper pump housing 1a and a lower pump housing 1b. The upper pump housing 1a and the lower pump housing 1b form a mounting hole 1c for mounting the annular mounting seat 5a. The outer ring of the annular mounting seat 5a is provided with an annular protrusion 5f. The mounting hole 1c is provided with an annular groove 1d that matches the annular protrusion 5f. The sealing body 5 is fixedly installed in the mounting hole 1c by the annular protrusion 5f and the annular groove 1d.

[0054] Furthermore, the material of the sealing body 5 is stainless steel or cast iron, the sealing device is a mechanical seal, the outer side of the pump casing 1 is provided with a bearing seat mounted on the sealing body 5, a bearing is provided between the bearing seat and the rotating shaft 4, and the end face of the sealing body 5 near the bearing seat is recessed to form an installation groove for installing the mechanical seal end cover.

[0055] Structure of partition 6 and sealing body 5: The partition 6 is fixedly connected to the sealing body 5 by welding.

[0056] The bearing housing is installed by screws passing through it and connecting it to the seal body 5. The mechanical seal is installed by screws passing through the mechanical seal end cover and connecting it to the seal body 5.

[0057] A double-suction pump employing the semi-spiral suction chamber 2 of this invention and equipped with five baffles on the sealing body 5 was subjected to noise tests compared with an existing double-suction pump. Figure 7 The noise experiment comparison chart shown shows that... Figure 7It can be clearly seen that the noise of the dual-suction pump of the present invention is significantly lower than that of existing dual-suction pumps.

[0058] The above embodiments are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, all equivalent changes made in accordance with the structure, shape, and principle of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A low-noise semi-spiral suction chamber design method, comprising a pump casing (1), wherein a semi-spiral suction chamber (2) and an impeller (3) are provided inside the pump casing (1), characterized in that: A sealing body (5) is provided between the pump casing (1) and the shaft (4) of the impeller (3). The sealing body (5) is located on the outer side of the semi-spiral suction chamber (2) away from the impeller (3). A baffle (6) extending into the semi-spiral suction chamber (2) is provided on the sealing body (5). The semi-spiral suction chamber (2) includes a cross-section with an angle θ of 0 and n cross-sections, with the cross-sectional area ranging from S... a To S n The number of cross-sections increases sequentially, with n being an integer. The formula for calculating n is: in The angle between each section, Cross-sectional area S n The calculation formula is: Q d V is the design flow rate of the pump. im The inlet velocity of the impeller (3); when n≥2, the cross-sectional area S n-1 The calculation formula is S n-1 =k s S n ,in θ is the angle of the cross section; when θ < 90°, the outlet of the semi-spiral water absorption chamber (2) is a symmetrical structure about the cross section a, and the cross section a is a vertical plane.

2. The low-noise semi-spiral water absorption chamber design method according to claim 1, characterized in that: The formula for calculating the height H of the partition (6) is H = k m D f D f k is the diameter of the sealing body (5). m =0.2~0.7Df.

3. The low-noise semi-spiral water absorption chamber design method according to claim 1, characterized in that: There is one partition (6), located at section a.

4. The low-noise semi-spiral water absorption chamber design method according to claim 1, characterized in that: There are two or more partitions (6), one of which is located at section a.

5. The low-noise semi-spiral water absorption chamber design method according to claim 1, characterized in that: The outer end of the partition (6) is wavy along its width direction.

6. The low-noise semi-spiral water intake chamber design method according to claim 5, characterized in that: The wavy curve is a sine function curve.

7. The low-noise semi-spiral water absorption chamber design method according to claim 1, characterized in that: The inlet of the semi-spiral water absorption chamber (2) consists of three sections, and the two sections near the outlet of the semi-spiral water absorption chamber (2) are smoothly transitioned.

8. The low-noise semi-spiral water absorption chamber design method according to claim 1, characterized in that: The sealing body (5) includes an annular mounting seat (5a) mounted on the pump casing (1) and an annular mounting portion (5b) for mounting the partition plate (6). The outer wall (5c) of the annular mounting portion (5b) is a concave arc surface, and its diameter gradually decreases from the connection with the annular mounting seat (5a) outward. The outer wall (5c) of the annular mounting portion (5b) and the inner wall (5d) are transitioned by a rounded corner (5e). The end of the partition plate (6) near the annular mounting seat (5a) is disposed on the outer wall (5c), the rounded corner (5e), ​​and the outer end of the inner wall (5d).

9. The low-noise semi-spiral water intake chamber design method according to claim 8, characterized in that: The material of the sealing body (5) is the same as that of the pump housing (1). A sealing device is provided between the sealing body (5) and the rotating shaft (4). The pump housing (1) includes an upper pump housing (1a) and a lower pump housing (1b). The upper pump housing (1a) and the lower pump housing (1b) form a mounting hole (1c) for mounting the annular mounting base (5a). The outer ring of the annular mounting base (5a) is provided with an annular protrusion (5f). The mounting hole (1c) is provided with an annular groove (1d) that matches the annular protrusion (5f). The sealing body (5) is fixedly installed in the mounting hole (1c) through the annular protrusion (5f) and the annular groove (1d).

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