Design method for pump volute for large-scale construction and the volute thereof

Abstract

To provide a design method of a large-scale construction pump volute which can reduce pressure pulsation and a radial force at an operation of a pump, and can improve operation safety and stability at each opening condition of the pump, and the volute.SOLUTION: A large-scale construction pump volute includes a volute outlet, a diffusion segment (2), a throat part (3), a movable guide vane (5), a fixed guide vane (6), an outlet guide vane (7), and a partitioning tongue (8). A plurality of the fixed guide vanes are arranged at an external periphery of the movable guide vane, the outlet guide vane substantially tangentially contacts with a base circle D3 of an inlet of a pressurization water chamber, an inlet end of the outlet guide vane has a cross section I, a partitioning tongue end has a cross section II, the volute is an annular volute extending up to the cross section I from the cross section II in a flow direction, and circulation areas of the cross sections of a volute flow passage are substantially the same.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to the technical field of pump volutes for hydraulic engineering and centrifugal pump volutes. Specifically, it relates to a design method for pump volutes for large-scale engineering and the volutes thereof.

Background Art

[0002] In recent years, China's water conservancy and hydropower projects have developed sufficiently, meeting the demand for power energy in China and laying a solid foundation for the implementation of China's sustainable development strategy. The volute is an important flow-through component of a centrifugal pump and has a significant impact on the efficiency index of the pump. When the fluid enters the volute from the impeller, due to the small gap between the impeller and the cut-off tongue / tongue part of the volute, a strong interaction occurs, resulting in high-amplitude and low-frequency pressure pulsations in the cut-off tongue area of the conventional spiral volute. In addition, since the geometric structure of the spiral volute is asymmetric, when the head and flow rate are high, large pressure pulsations and radial forces are generated, resulting in large vibrations and noises, which affect the operating stability of pumps for large-scale water conservancy projects. In response to this problem, Chinese Utility Model Publication No. CN201218236Y discloses a high-speed water pump volute, including a continuous volute passage composed of a circular volute bottom and a continuous side wall with an involute or Archimedes spiral, and a volute provided with a water inlet and a drain outlet of the pump. The center of the volute is the water inlet, and the continuous side wall is a water stop plate, which has the characteristics of increasing the head height and water flow rate, being light in weight, corrosion-resistant, easy to manufacture, and low in cost. Chinese Patent Application Publication No. CN111894903A discloses a volute of a serialized single-stage centrifugal pump and a design method. When designing different flow rates and the same outer diameter of the impeller, the axial wall thickness of the pump body close to the pump cover side may be the same, and the pump cover can be designed in a general shape. The pressurized water chamber uses an axially asymmetric cross-section. Based on the center line, the cross-section close to the pump cover side is rectangular, and the other side is a right trapezoid, effectively reducing the perturbation degree of the rotating shaft, improving the reliability of sealing, and reducing the vibration of the pump. In this way, the production efficiency is improved, the mechanical strength is improved, and the pressure pulsation is reduced to a certain extent. However, when using a trapezoidal or rectangular cross-section, the pressure head and efficiency of the pump are low. Therefore, it is necessary to design a pump volute structure for large-scale water conservancy projects that can be widely applied, has small pressure pulsations, stable radial forces, and can operate efficiently.

[0003] The structure of a conventional volute includes a volute body, and a water flow passage is provided in the volute body. The water flow passage generally consists of a pressurized water chamber and a diffusion segment. The starting end of the pressurized water chamber is a partition tongue, the connection part between the pressurized water chamber and the diffusion segment is a throat part, and the outlet of the diffusion segment is the pump body outlet. The conventional pressurized water chamber is configured by connecting a set of cross-sections that increase from the partition tongue part along the rotation direction of the impeller towards the throat part at the inlet of the diffusion segment of the pump, with reference to the design base circle outside the outer circle of the impeller. The cross-section of the pressurized water chamber uses an eccentric ellipse, trapezoid, or semi-circular arc-shaped cross-section to improve the pressure head and efficiency of the pump.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In order to solve the deficiencies of the prior art, the present invention aims to provide a design method for a large-scale construction pump volute and the volute thereof, which can reduce the pressure pulsation and radial force during the operation of the pump, and improve the operation safety and stability of the pump under various operating conditions.

Means for Solving the Problems

[0006] To achieve the above object, the technical solution used in the present invention is as follows.

[0007] It includes a volute outlet (1), a diffuser segment (2), a throat section (3), a fixed multi-channel (4), movable guide vanes (5), fixed guide vanes (6), outlet guide vanes (7), a partition tongue / tongue section (8), and a flow path gap (9). A diffuser segment is provided at the outlet end of the pressurized water chamber. The outlet end of the diffuser segment has a volute outlet. The connection part between the pressurized water chamber and the diffuser segment is the throat section. A diffuser is provided on the outer circumference of the impeller. The diffuser includes a plurality of movable guide vanes distributed in the circumferential direction. A partition tongue is formed between the diffuser segment and the volute wall. It is a volute of a large-scale construction pump. A plurality of fixed guide vanes (6) are provided on the outer circumference of the movable guide vanes (5). The fixed guide vanes partition the volute flow path into fixed multi-channels. The center line / axis of the outlet guide vanes is collinear / parallel with the center line / axis of the diffuser segment. The outlet guide vanes are substantially tangent to the basic circle D3 of the inlet of the pressurized water chamber. There is a flow path gap (9) between the outlet end of the fixed guide vane and the inlet end of the radially inner fixed guide vane adjacent thereto or the basic circle D3 of the inlet of the pressurized water chamber. The inlet end of the outlet guide vanes has a cross-section I, and the partition tongue end has a cross-section II. The volute is an annular volute from cross-section II to cross-section I in the flow direction. The flow area of the cross-section of the volute flow path is substantially the same. This is the feature.

[0008] Furthermore, the volute uses an annular volute with a substantially eccentric elliptical cross-section. In the long-axis direction of the ellipse, the size of the long part of the eccentricity of the ellipse is 2 to 4 times the size of the short part.

[0009] Furthermore, the fixed guide vane (6) is an arc-shaped guide vane. The fixed guide vanes have different central angles. The central angle increases as it goes from cross-section II to cross-section I in the flow direction. From cross-section II to cross-section I in the flow direction, the downstream central angle is 1.05 to 1.25 times the upstream central angle.

[0010] Furthermore, the flow path gap (9) increases as it goes from cross-section II to cross-section I in the flow direction. From cross-section II to cross-section I in the flow direction, the downstream flow path gap is 1.05 to 1.2 times the upstream flow path gap.

[0011] Furthermore, the fixed guide vane (6) has a downstream end / trailing edge end (61), the downstream end is tapered or arcuate, the downstream end has a first concave groove (62) and a second concave groove (63), a plurality of the first concave grooves are provided on the radially inner surface of the downstream end, a plurality of the second concave grooves are provided on the radially outer surface of the downstream end, and the first concave groove and the second concave groove have a semi-circular structure.

[0012] Furthermore, the number of the first concave grooves (62) is larger than the number of the second concave grooves (63), and the number of the first concave grooves is 1.5 to 3.0 times the number of the second concave grooves.

[0013] Furthermore, the diffuser segment is the pump body outlet. As the diffuser segment goes from the throat portion to the volute outlet, the area of the water flow passage increases. The cross-section of the diffuser segment includes a shape composed of a rectangle and / or an arc. The cross-sectional shape of the pressurized water chamber at the throat portion position is the same as and overlaps with the end face shape of the diffuser segment, and this structure ensures a smooth transition between the water chamber and the diffuser segment.

[0014] A design method for the volute of a large-scale construction pump, using an annular volute structure with fixed guide vanes and movable guide vanes. According to predetermined operating conditions, based on the volute speed coefficient method, the basic circle diameter D of the inlet of the pressurized water chamber 3 , the inlet width B of the pump pressurized water chamber 3 , the radius R of the outer contour line of the volute chamber, the number Z of movable guide vanes 1 , the number Z of fixed guide vanes 2 , and the geometric parameters of the volute including the diffusion angle θ are determined.

[0015] D 3 = D 2 +2b 2 As shown, step (1) of designing the basic circle diameter D of the inlet of the pressurized water chamber 3 , where

[0016] In the formula, b 2 - The radius of the movable guide vane, in mm, D 2 - The outer diameter of the pump impeller, in mm. D 3 - The basic circle diameter of the inlet of the pump pressurized water chamber, in mm, step (1), and B 3 = B 2 + 0.05D 3 As such, step (2) of designing the inlet width B of the pump pressurized water chamber, 3 wherein,

[0017] In the formula, B 2 - The axial width of the pump impeller outlet, in mm, D 3 - The basic circle diameter of the inlet of the pump pressurized water chamber, in mm, B 3 - The inlet width of the pump pressurized water chamber, in mm, step (2), and JPEG0007689689000001.jpg20153 As such, step (3) of designing the radius R of the outer contour line of the volute chamber,

[0018] In the formula, A I - The area value of the first cross-section of the volute, in mm, R - The radius of the outer contour line of the volute chamber, in mm, step (3), and Z 1 = 8 to 14, as such, the number Z of movable guide vanes 1 is designed in step (4),

[0019] In the formula, Z 1 - The number of movable guide vanes, in pieces, step (4), and Z 2 = 3 to 5, as such, the number Z of fixed guide vanes 2 is designed in step (5),

[0020] In the formula, Z 2 - The number of fixed guide vanes, in pieces, step (5), and JPEG0007689689000002.jpg24158 As shown in , step (6) of designing the diffusion angle of the diffusion segment,

[0021] In the formula, A I - The area value of the first cross-section of the volute, in mm, D S - The diameter of the volute outlet, in mm, L - The length of the diffusion segment of the volute, in mm, θ - The diffusion angle, in °, Step (6) of setting θ to 6° to 12°. A method for designing a volute of a large-scale construction pump, characterized by including this.

Advantages of the Invention

[0022] The present invention has the following beneficial technical effects. (1) Using the structure of the annular volute, the annular volute has a symmetrical flow passage compared with the conventional spiral volute, and there is a large gap between the partition tongue and the impeller outlet. By using the annular volute instead of the conventional volute, the pressure pulsation and radial force of the pump can be reduced, and the operation stability can be improved. The gap between the outer circumference of the impeller and the volute partition tongue increases, and the advantage is that the impact of the water flow on the volute partition tongue is reduced, and since the gap between the partition tongue and the impeller increases, the pressure pulsation and the overall radial force can be reduced.

[0023] (2) By further design, the fixed guide vanes have different central angles, and the central angles increase as the cross-section changes from cross-section II to cross-section I in the flow direction. The flow path gap increases as the cross-section changes from cross-section II to the cross-section in the flow direction. During the operation of the pump, the pressure pulsation and radial force can be further reduced, the corner vortex at the fixed guide vane outlet can be decreased, the pressure fluctuation and pressure loss of the annular volute can be reduced, and the operation safety and stability under each operating condition of the pump can be improved. The present invention can further reduce the corner vortex at the fixed guide vane outlet, reduce the pressure fluctuation and pressure loss of the annular volute by designing the first concave groove and the second concave groove, thereby improving the operation safety and stability under each operating condition of the pump.

[0024] (3) By providing two rows of guide vanes (movable guide vanes and fixed guide vanes) in the volute, the high-speed liquid separated from the impeller can be collected and uniformly guided to the inlet of the next-stage impeller or the discharge chamber. A part of the kinetic energy of the liquid can be converted into pressure energy by the guide vanes, thereby improving the efficiency of the pump. By using two rows of guide vanes, the hydraulic performance is significantly improved compared with that without fixed guide vanes or with a single row of fixed guide vanes. Considering that the cross-section of the volute uses an eccentric elliptical cross-section, the influence of the cross-section shape on the hydraulic performance of the centrifugal pump is analyzed, and it can be found that the elliptical cross-section shape in the annular volute gives a higher pump pressure head than a trapezoidal, semi-circular or rectangular shape.

Brief Description of the Drawings

[0025]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Embodiments for Carrying Out the Invention

[0026] In order to make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, hereinafter, in conjunction with the drawings of the embodiments of the present invention, the technical solutions of the embodiments of the present invention will be clearly and completely described. It is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. According to the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative labor belong to the protection scope of the present invention.

[0027] Hereinafter, the present invention will be described in more detail with reference to the drawings.

[0028] As shown in FIGS. 1 to 2, it includes a volute outlet 1, a diffuser segment 2, a throat portion 3, a fixed multi-channel 4, a movable guide vane 5, a fixed guide vane 6, an outlet guide vane 7, a partition tongue / tongue portion 8, and a flow path gap 9. The diffuser segment 2 is provided at the outlet end of the pressurized water chamber. The outlet end of the diffuser segment 2 has the volute outlet 1. The connection portion between the pressurized water chamber and the diffuser segment 2 is the throat portion 3. A diffuser is provided on the outer periphery of the impeller. The diffuser includes a plurality of movable guide vanes 5 distributed in the circumferential direction. A partition tongue 8 is formed between the diffuser segment 2 and the volute wall. A design method of a volute for a large-scale construction pump and the volute thereof, on the outer periphery of the movable guide vane 5, a plurality of fixed guide vanes 6 for partitioning the volute flow path into the fixed multi-channel 4 are provided. The center line / axis of the outlet guide vane 7 is collinear / parallel with the center line / axis of the diffuser segment 2. The outlet guide vane 7 is substantially tangent to the base circle D3 of the inlet of the pressurized water chamber. There is a flow path gap 9 between the outlet end of the fixed guide vane 6 and the inlet end of the radially inner fixed guide vane 6 adjacent thereto or the base circle D3 of the inlet of the pressurized water chamber. The inlet end of the outlet guide vane 7 has a cross-section I, and the partition tongue 8 end has a cross-section II. The volute is an annular volute from the cross-section II to the cross-section I in the flow direction, and the flow area of the cross-section of the volute flow path is the same, which is characterized by this.

[0029] Furthermore, as shown in FIG. 3, the volute uses an annular volute B with a substantially eccentric elliptical cross-section. In the long axis direction of the ellipse (X-axis direction), the size of the long part of the eccentricity of the ellipse is 2 to 4 times, preferably 2.5 times, the size of the short part.

[0030] Furthermore, the fixed guide vane 6 is an arc-shaped guide vane, and the fixed guide vanes 6 have the same or different central angles. Preferably, the fixed guide vanes 6 have different central angles, and the central angle increases as it goes from the cross-section II to the cross-section I in the flow direction. Specifically, from the cross-section II to the cross-section I in the flow direction, the downstream central angle is 1.05 to 1.25 times the upstream central angle.

[0031] Furthermore, the flow path gap 9 increases as it goes from cross-section II to cross-section I in the flow direction. Specifically, from cross-section II to cross-section I in the flow direction, the downstream flow path gap 9 is 1.05 to 1.2 times that of the upstream flow path gap 9.

[0032] As shown in FIG. 1, the volute has a substantially constant cross-sectional flow area from cross-section II to cross-section I in the flow direction. Next, the gap between the outer circle of the impeller and the volute partition tongue 8 increases, and the advantage is that it can reduce the impact of solid particles on the volute tongue, and since the gap between the partition tongue and the impeller increases, the pressure pulsation and the overall radial force can be reduced.

[0033] The diffusion segment 2 is the pump body outlet. As the diffusion segment goes from the throat portion 3 to the volute outlet 1, the area of the water flow path increases, and the cross-section of the diffusion segment includes a shape composed of a rectangle and / or an arc. The cross-sectional shape of the pressurized water chamber in the throat portion 3 is the same as and overlaps with the end face shape of the diffusion segment 2, and this structure ensures a smooth transition between the pressurized water chamber and the diffusion segment.

[0034] As shown in FIG. 2, compared with the conventional spiral volute, the annular volute has a larger and more uniform flow cross-sectional area. If the cross-sectional area of the volute is small, a hump peak will occur in the pump head curve, resulting in surging in the pipe system. Under rated operating conditions, as the flow-through area of the volute increases, the hydraulic performance decreases slightly. When the operation of the pump deviates from the rated operating conditions, if the flow area of the volute is large, the hydraulic performance is improved, and as the flow area of the volute increases, the high-efficiency region becomes wider.

[0035] The volute uses a substantially eccentric elliptical cross-section instead of the conventional trapezoidal or semi-circular volute cross-section, which is advantageous for reducing the pressure pulsation in the volute.

[0036] As shown in Fig. 4(a), by using an annular volute, the radial force can be reduced within the low flow rate range. Similarly, when the pump operates below the optimal efficiency point, these volutes generate higher head and efficiency. In these volutes, due to the large blade tip clearance, the interaction between the impeller blades and the volute partition tongue is reduced, and thus the pressure distribution around the impeller becomes more uniform. During design, due to the non-uniform pressure distribution around the impeller caused by a constant cross-sectional area volute, the minimum radial force point occurs at a low flow rate rather than the design flow rate.

[0037] The distribution of the radial force in Fig. 4(b) is shown as a quadrilateral and coincides with the angle of the impeller blades. Also, as the flow rate increases, the quadrilateral rotates clockwise, and by increasing the flow area of the volute, the magnitude of the radial force acting on the shaft can be reduced. Especially under the conditions of nominal flow rate and large flow rate, the vibration of the pump can be reduced, thereby improving the operating stability of the pump.

[0038] As shown in Fig. 4(c), from the broken line distribution of the annular volute of the fluctuation intensity coefficient, it can generally be seen that the coefficient increases as the flow rate increases. Also, all the multiple lines show four peaks, which coincide with the number of impeller blades. The equivalent deflection angle of the four peaks is 90°. The maximum pressure pulsation occurs at about 30° after the partition tongue of the volute, which means that the interaction between the trailing edge of the impeller and the volute partition tongue is the cause of the pressure pulsation in the volute. Also, increasing the flow area of the volute reduces the pressure pulsation in the volute regardless of the operating state of the pump.

[0039] Preferably, by further design, the fixed guide vane 6 has different central angles, and the central angle increases as it goes from cross-section II to cross-section I in the flow direction. The flow path clearance 9 increases as it goes from cross-section II to cross-section I in the flow direction. The pressure pulsation and radial force during the operation of the pump can be further reduced, the corner vortex at the outlet of the fixed guide vane can be reduced, the pressure fluctuation and pressure loss of the annular volute can be reduced, and the operating safety and stability under each operating condition of the pump can be improved.

[0040] As shown in FIG. 5, in one embodiment, the fixed guide vane 6 has a downstream end / trailing edge end 61, and the downstream end / trailing edge end 61 is in a tapered shape or an arc shape that tapers towards the end, and the downstream end 61 has a first concave groove 62 and a second concave groove 63. A plurality of first concave grooves 62 are provided on the radially inner surface of the downstream end 61, and a plurality of second concave grooves 63 are provided on the radially outer surface of the downstream end 61. The first concave groove 62 and the second concave groove 63 have a semi-circular structure. By designing the first concave groove 62 and the second concave groove 63, the corner vortex at the outlet of the fixed guide vane is further reduced, the pressure fluctuation and pressure loss of the annular volute are reduced, thereby improving the operation safety and stability under each operating condition of the pump.

[0041] Furthermore, the number of the first concave grooves 62 is larger than the number of the second concave grooves 63. Preferably, the number of the first concave grooves 62 is 1.5 to 3.0 times the number of the second concave grooves 63.

[0042] A design method for the volute of a large-scale construction pump, which uses an annular volute structure with fixed guide vanes and movable guide vanes. According to predetermined operating conditions, based on the volute speed coefficient method, the basic circle diameter D at the inlet of the pressurized water chamber 3 , the inlet width B of the pump pressurized water chamber 3 , the radius R of the outer contour line of the volute chamber, the number Z of movable guide vanes 1 , the number Z of fixed guide vanes 2 , the geometric parameters of the volute including the diffusion angle θ are determined,

[0043] D 3 = D 2 +2b 2 As shown above, the step (1) of designing the basic circle diameter D at the inlet of the pressurized water chamber 3 wherein,

[0044] In the formula, b 2 - the radius of the movable guide vane, in mm, D 2 - the outer diameter of the pump impeller, in mm, D 3- Step (1), which is the basic circle diameter at the inlet of the pump pressurized water chamber, in mm, B 3 =B 2 +0.05D 3 As shown, step (2) of designing the inlet width B of the pump pressurized water chamber 3 wherein,

[0045] In the formula, B 2 - The axial width at the outlet of the pump impeller, in mm, D 3 - The basic circle diameter at the inlet of the pump pressurized water chamber, in mm, B 3 - Step (2), which is the inlet width of the pump pressurized water chamber, in mm, JPEG0007689689000003.jpg20153 As shown, step (3) of designing the radius R of the outer contour line of the volute chamber

[0046] In the formula, A I - The area value of the first section of the volute, in mm, R - The radius of the outer contour line of the volute chamber, in mm, step (3) Z 1 = 8 to 14, like this, the number Z of the movable guide vanes 1 Step (4) of designing

[0047] In the formula, Z 1 - The number of the movable guide vanes, in pieces, step (4) Z 2 = 3 to 5, like this, the number Z of the fixed guide vanes 2 Step (5) of designing

[0048] In the formula, Z 2 - The number of the fixed guide vanes, in pieces, step (5) JPEG0007689689000004.jpg24158 Step (6) of designing the diffusion angle of the diffusion segment, which is

[0049] In the formula, A I - The area value of the first cross-section of the volute, in mm, D S - The diameter of the volute outlet, in mm, L - The length of the diffusion segment of the volute, in mm, θ - The diffusion angle, in °, Including step (6) of setting θ to 6° to 12°.

[0050] In order to reduce the volume of the pump and the diameter of the discharge pipe, reduce the pipe loss, thereby reducing the head of the pump, reducing the power of the pump, saving energy, and reducing the operating cost, the discharge diameter can be made less than the suction diameter. After initially determining the diameter of the pump outlet, round it according to the standard pipe diameter series. In order to reduce the size of the pump, for the height L of the diffuser / diffusion segment, use the smallest possible value while ensuring the diffusion angle, machining, and bolt connection.

[0051] The present invention has the following beneficial technical effects.

[0052] (1), Using the structure of the annular volute, the annular volute has a symmetrical flow passage compared with the conventional spiral volute, and there is a large gap between the partition tongue and the impeller outlet. By using the annular volute instead of the conventional volute, the pressure pulsation and radial force of the pump can be reduced, and the operation stability can be improved. The gap between the outer periphery of the impeller and the volute partition tongue increases, and the advantage is that the impact of the water flow on the volute partition tongue is reduced, and since the gap between the partition tongue and the impeller increases, the pressure pulsation and the overall radial force can be reduced.

[0053] (2) By further design, the fixed guide vanes have different central angles, and the central angle increases as it goes from cross-section II to cross-section I in the flow direction. The flow path gap increases as it goes from cross-section II to the cross-section in the flow direction. During the operation of the pump, the pressure pulsation and radial force can be further reduced, the corner vortex at the fixed guide vane outlet can be decreased, the pressure fluctuation and pressure loss of the annular volute can be reduced, and the operation safety and stability under each operating condition of the pump can be improved. The present invention can further reduce the corner vortex at the fixed guide vane outlet and the pressure fluctuation and pressure loss of the annular volute by designing the first concave groove and the second concave groove, thereby improving the operation safety and stability under each operating condition of the pump.

[0054] (3) By providing two rows of guide vanes (movable guide vanes, fixed guide vanes) in the volute, the high-speed liquid separated from the impeller can be collected and uniformly guided to the inlet of the next-stage impeller or the discharge chamber, and a part of the kinetic energy of the liquid can be converted into pressure energy in the guide vanes, thereby improving the efficiency of the pump. By using two rows of guide vanes, the hydraulic performance is greatly improved compared with that without fixed guide vanes or with a single row of fixed guide vanes. Considering that the cross-section of the volute uses an eccentric elliptical cross-section, the influence of the cross-section shape on the hydraulic performance of the centrifugal pump is analyzed, and it can be seen that the elliptical cross-section shape in the annular volute gives a higher pump pressure head than a trapezoidal, semi-circular or rectangular shape.

[0055] The above embodiments are descriptions of the present invention, not limitations to the present invention. Without departing from the principle and spirit of the present invention, these embodiments can be variously changed, modified, substituted and deformed. It is understood that the protection scope of the present invention is limited by the appended claims and their equivalents.

Explanation of Reference Numerals

[0056] Volute outlet 1, diffuser segment 2, throat section 3, fixed multi-channel 4, movable guide vane 5, fixed guide vane 6, outlet guide vane 7, partition tongue / tongue part 8, flow path gap 9, D2 impeller outer diameter, D3 basic circle diameter of the inlet of the pressurized water chamber, R radius of the outer contour line of the volute chamber, downstream end / trailing edge end 61, first concave groove 62, second concave groove 63

Claims

1. A volute includes a volute outlet (1), a diffuser segment (2), a throat section (3), a fixed multi-channel (4), movable guide vanes (5), fixed guide vanes (6), outlet guide vanes (7), a partition tongue (8), and a flow path gap (9). The diffuser segment (2) is provided at the outlet end of the pressurized water chamber. The outlet end of the diffuser segment (2) has the volute outlet (1). The connection part between the pressurized water chamber and the diffuser segment (2) is the throat section (3). A diffuser is provided on the outer circumference of the impeller. The diffuser includes a plurality of the movable guide vanes (5) distributed in the circumferential direction. A partition tongue is formed between the diffuser segment (2) and the volute wall. It is a volute of a construction pump, wherein a plurality of the fixed guide vanes (6) are provided on the outer circumference of the movable guide vanes (5). The fixed guide vanes (6) partition the volute flow path into a fixed multi-channel (4). The axis of the outlet guide vanes (7) is collinear or parallel with the axis of the diffuser segment (2). The outlet guide vanes (7) are substantially tangent to the base circle D3 of the inlet of the pressurized water chamber. There is a flow path gap (9) between the outlet end of the fixed guide vanes (6) and the inlet end of the adjacent radially inner fixed guide vanes (6) or the base circle D3 of the inlet of the pressurized water chamber. The volute has a cross-section I at the inlet end of the outlet guide vanes (7) and a cross-section II at the end of the partition tongue. The volute is an annular volute from cross-section II to cross-section I in the flow direction. The flow area of the cross-section of the flow path of the volute is substantially the same. It is a volute of a construction pump, characterized in that.

2. Using the structure of the annular volute with the fixed guide vanes (6) and the movable guide vanes (5), According to predetermined operating conditions, based on the volute speed coefficient method, The base circle diameter D of the inlet of the pressurized water chamber ３ , the inlet width B of the pressurized water chamber ３ , the radius R of the outer contour line of the volute chamber, the number Z of the movable guide vanes (5) １ , the number Z of the fixed guide vanes (6) ２ , determine the geometric parameters of the volute including the spread angle θ of the diffusion segment (2), D ３ = D ２ + 2b ２ whereby, in step (1) of designing the basic circle diameter D at the inlet of the pressurized water chamber ３ as follows In the above formula, b ２ - The difference, in mm, between the outer radius of the plurality of the movable guide vanes (5) distributed circumferentially along the outer circumference of the pump impeller and the radius of the pump impeller D ２ - The outer diameter of the pump impeller, in mm, and D ３ - the basic circle diameter of the inlet of the pressurized water chamber, in mm, of step (1), and B ３ = B ２ + 0.05D ３ whereby, in step (2) of designing the inlet width B ３ of the pressurized water chamber In the above formula, B ２ - The axial width of the pump impeller outlet, in mm, D ３ - The basic circle diameter of the inlet of the pressurized water chamber, in mm, and B ３ - the inlet width of the pressurized water chamber, in mm, of step (2), A step (3) of designing the radius R of the outer contour line of the volute chamber, In the above formula, A Ｉ - the area value of the cross-section I of the volute, in mm, R - the radius of the outer contour line of the volute chamber, in mm. Step (3) and, Z １ = 8 to 14, the number Z of the movable guide vanes (5) １ in the step (4) of designing In the above formula, Z １ - the number, in pieces, of the movable guide vanes (5), step (4), and Z ２ = 3 to 5, the number Z of the fixed guide vanes (6) ２ in the step (5) of designing In the above formula, Z ２ - the number, in pieces, of the fixed guide vanes (6), step (5), and A step (6) of designing the divergence angle of the diffuser segment (2), In the above formula, A Ｉ - the area value of the cross-section I of the volute, in mm, D Ｓ - the diameter of the volute outlet (1), in mm, L - the length in the axial direction of the axis of the diffuser segment (2) of the volute, in mm, θ - the divergence angle of the diffuser segment (2), in °, A method for designing a volute of a construction pump according to claim 1, comprising a step (6) of setting θ to 6° to 12°.

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