TW202113233A - Three-dimensional plastic impeller for centrifugal pump and method for manufacturing the same - Google Patents

Abstract

The disclosure relates to a three-dimensional plastic impeller for a centrifugal pump and method for manufacturing the same using molds. The molds include a first mold for twisted portion of impeller blades and a second mold for outer part of impeller. The first mold is configured to manufacture twisted portions of impeller blades, and the second mold is configured to manufacture outer portions of the impeller blades, a hub rim part and a shroud rim part so that the impeller blades, the hub rim part and the shroud rim part of the impeller are allowed to be formed into a single piece by the same molding process.

Description

Manufacturing method and structure of 3-dimensional plastic impeller of centrifugal pump

The present invention relates to a method for manufacturing a pump impeller, particularly a method for manufacturing a pump impeller made of engineering plastic material, which is suitable for the production of plastic impellers with high-efficiency 3-dimensional runners, and can be injection molded or transferred into It can solve the problem of easy production but low efficiency of traditional 2-dimensional impellers.

The issue of saving energy and reducing carbon dioxide emissions has been taken seriously by various countries, and improving the efficiency of power machinery and equipment has become the direction of the efforts of all industries. According to the International Energy Agency (IEA), the electricity consumption of pumps accounts for about the electricity consumption of motors. 19%, and since 2015, the EU has stipulated that the Minimum Efficiency Index (MEI) of water pumps must be greater than or equal to 0.4. Therefore, the industry is all committed to the development of high-efficiency pumps, but at the same time, the production economy must also be considered .

，該文獻中也提到泵浦葉輪幾何、操作區域(流量Q，揚程H)的關係，離心式泵浦比轉速大約落在 380~1750

之間，比轉速愈大的葉輪，葉片扭曲的程度愈大，文獻中也提到，二維葉片是典型的低比轉速葉片，且二維葉片在軸向(z軸)各個位置均有相同線形(shape)，所以葉片上緣曲線(shroud edge)與下緣曲線(hub edge)將會重疊，反之，3維葉片上緣曲線(shroud edge)與下緣曲線(hub edge)會有不同線形(shape)及葉片角(blade angle)。Reference 1, the third edition section 2.1 (Centrifugal pump theory) of "PUMP HANDBOOK" written by Paul Cooper and published by McGRAW-HILL in 2001, its figure 9 (Optimum geometry as a function of BEP specific speed) and figure 10 (Efficiency of centrifugal pumps versus specific speed), which explains the parameters commonly used in the pump industry. The definition of specific speed is as follows:

, The document also mentions the relationship between pump impeller geometry and operating area (flow Q, head H). The specific speed of the centrifugal pump is about 380~1750.

Among them, the higher the specific speed of the impeller, the greater the degree of blade distortion. It is also mentioned in the literature that the two-dimensional blade is a typical low specific speed blade, and the two-dimensional blade has the same position in the axial direction (z axis). Line shape, so the upper edge curve (shroud edge) and lower edge curve (hub edge) of the blade will overlap. On the contrary, the 3D blade upper edge curve (shroud edge) and lower edge curve (hub edge) will have different line shapes (shape) and blade angle.

上的葉片角(blade angle)變化，可以看出葉片出口角度相同，但愈靠近入口端，上緣曲線(shroud edge)與下緣曲線(hub edge)的葉片角(blade angle)差異愈大，葉片扭曲愈大。Figure 19 of the reference 1 (conformal transformation of blade shape) illustrates that the expansion of the blade streamline is drawn by the conformal transformation method, which can clearly define the flow of different streamlines from the exit to the entrance. Line coordinates

The upper blade angle changes, it can be seen that the exit angle of the blade is the same, but the closer to the entrance end, the greater the difference between the blade angle of the shroud edge and the hub edge. The more the blade is twisted.

A centrifugal impeller is an important element of a rotating fluid machine. It can be used to transport fluids containing liquids or gases, and can be applied to wind turbines or pumps. The centrifugal impeller of the pump is installed in a volute. The fluid flows in from the inlet of the volute and enters the impeller axially from the inlet of the shaft of the impeller. The interior of the impeller has a plurality of radial or oblique blade flow channels (blade flow channels) composed of arc-shaped blades (blade). The rotating shaft drives the impeller to rotate, and uses centrifugal force and Coriolis force to transfer mechanical energy to the fluid through the blades to increase the flow rate and pressure of the fluid. With the guidance of the blades, the direction of fluid movement changes from axial to radial, and the fluid enters the scroll channel of the scroll pump casing after leaving the blade channel, and its high-speed kinetic energy is recovered as static through the diffusion of the scroll channel. Pressure and discharge from the outlet of the scroll pump casing.

In the axial direction, a front shroud and a hub are respectively provided at the front and rear of the blades of the centrifugal impeller to restrict the flow of fluid in the blade channel. The rear cover is directly connected to the rotating shaft to transmit the shaft power to the blades. The front cover is used to restrict the flow of fluid, and can also increase the overall strength of the blades and bear the pressure difference between the inside of the scroll pump casing and the blade channel.

Generally, centrifugal pumps can be equipped with open impellers, semi-open impellers or closed impellers. There is no front cover in the open impeller, and only a part of the rear cover is reserved to connect the blades and the rotating shaft. The impeller is installed between the front wall and the rear wall of the pump casing, mainly depending on the impeller and the front wall and the rear wall of the pump casing. To control the flow field. The semi-open impeller also does not have a front cover plate, but has a complete rear cover plate to connect the blades and the rotating shaft, and mainly depends on the gap between the impeller and the front wall of the pump casing to control the flow field. Closed impellers usually have a front cover and a rear cover at the same time. There is no gap between the impeller runners, which has a high efficiency. The front cover, the rear cover and the blades are usually integrated to provide sufficient mechanical strength and Effectively isolate the liquid in the flow path of each blade.

Here, please refer to FIGS. 1A, 1B, and 1C, where FIG. 1A shows a schematic side sectional view of a conventional impeller with two-dimensional blades, FIG. 1B shows a schematic top view of the impeller of FIG. 1A, and FIG. 1C shows Figure 1A is a streamline development view of a two-dimensional blade. It should be noted that since the impeller is a rotating mechanical element, cylindrical coordinates are usually used to describe the geometric shape of the impeller. As shown in Figure 1A, the surface of the impeller sectioned in the axial direction is called the r_z plane or the meridional plane (meridional). , Can describe the geometric shape of the flow channel that the fluid enters the impeller from the impeller inlet from the axial direction to the radial direction, and can also describe the geometric shape of the flow channel between the front cover plate 11 and the rear cover plate 12, and in the figure The r_θ plane in 1B is a projection plane perpendicular to the axis plane, the front cover 11 has an inner surface 111, and the surface element of the inner surface 111 on the r_z plane is a straight line parallel to the r axis, in other words , The inner surface 111 is a two-dimensional disc plane; the rear cover 12 has an inner surface 121, the constituent elements of the inner surface 121 in the r_z plane are non-planar straight lines on the r-axis, and the inner surface 121 is a conical surface .

，[

]，代表r_z面從m=0之上緣曲線134、中間曲線(mean)138與下緣曲線135的長度，橫坐標為∫rdθ代表從∫rdθ=0之上緣曲線134、中間曲線(mean)138與下緣曲線135在r_θ面投影之的圓周長度。由於圖1B已清楚看到二維的葉片13的上緣曲線134與下緣曲線135完全重疊，因此各流線葉片角β，tanβ=dm/rdθ，完全相同，且也與r_θ面座標上看葉片13的角度相同。In FIG. 1A, the blade 13 is between the front cover 11 and the rear cover 12. The distance between the front cover 11 and the rear cover 12 is called the meridional width (meridional width) 131, and the change in the meridional width 131 is determined by The widest entrance width B11 of the blade 13 is gradually reduced to the narrowest exit width B12 of the blade 13, and the entrance of the blade 13 has a leading edge 132 on the r_z plane (meridian plane) coordinates. The blade 13 is combined with the front cover. One side of 11 has an upper edge curve (shroud edge) 134, the blade 13 has a lower edge curve (hub edge) 135 on the side where the rear cover plate 12 is combined, and the arc-shaped blade 13 has a trailing edge (trailing edge) on the exit side. 136, and there is a mean 138 between the upper edge curve 134 and the lower edge curve 135. In FIG. 1B, from the point of view of the r_θ plane coordinates, the upper edge curve 134 and the lower edge curve 135 completely overlap, and there may be a sector width 137 between the two blades 13 and the sector width The change of 137 from the inlet to the outlet of the blade 13 increases as the radius increases. In the expanded streamline diagram of Figure 1C, the ordinate is the streamline coordinate

, [

], represents the length of the upper edge curve 134, the middle curve (mean) 138 and the lower edge curve 135 of the r_z plane from m=0, the abscissa is ∫rdθ represents the upper edge curve 134, the middle curve (mean) from ∫rdθ=0 ) 138 and the lower edge curve 135 projected on the r_θ plane of the circumference of the length. Since Fig. 1B has clearly seen that the upper edge curve 134 and the lower edge curve 135 of the two-dimensional blade 13 are completely overlapped, the blade angle β of each streamline, tan β = dm/rdθ, is exactly the same, and it is also viewed on the plane coordinates of r_θ The angles of the blades 13 are the same.

In Figure 1D, the conventional manufacturing method of the 2-dimensional plastic impeller is to use the blade and the back cover to form an integral part. The molding method is to use a simple fixed mold and a movable mold to easily form it, and then heat it with the front cover. Or the welding column is combined into a complete impeller.

Considering that after the fluid is transported from the pump suction port into the impeller, it changes from axial flow to radial flow and circular motion. In order to achieve high efficiency of the centrifugal impeller, the blade shape of the suction port section must be a 2.5-dimensional or 3-dimensional curved surface, or Call it a twisted blade. The efficiency of 2.5-dimensional blades is much higher than that of 2-dimensional blades because the blade angles are more in line with the requirements of the flow field. However, only blades with 3-dimensional curved surfaces can fully meet the requirements of the flow field and achieve the goal of real high efficiency. Here, please refer to FIGS. 2A, 2B, and 2C, where FIG. 2A shows a schematic side sectional view of a traditional impeller without an upper cover plate and with three-dimensional blades, and FIG. 2B shows a schematic top view of the impeller of FIG. 2A. 2C shows the streamline development of the 3-dimensional blade of FIG. 2A. In FIG. 2B, the curved surface of the blade is called a 3-dimensional curved surface, and if the curved surface of the blade is a straight line, it is called a 2.5-dimensional curved surface. Compared with the aforementioned two-dimensional blade, the blade 23 in FIG. 2A is set on the rear cover 22, and the meridian width 231 of the blade 23 changes gradually from the widest entrance width B21 of the blade 23 to the narrowest exit of the blade 23 Width B22, the rear cover 22 has an inner surface 221. The constituent elements of the inner surface 221 on the r_z plane are arcs, making the inner surface 221 an inner convex cone; in this case, when forming such an impeller, the mold’s The runner slider must be divided into multiple groups, otherwise the runner slider cannot be taken out after the impeller is formed, especially at the entrance width B21 of the blade, it is most difficult to take out the runner slider.

On the r_z plane (meridian plane), the entrance of the blade 23 has a blade leading edge 232. The blade 23 has an upper edge curve 234 on the side away from the rear cover 22, and the blade 23 has a lower edge on the side where the rear cover 22 is combined. Curve 235, the arc-shaped blade 23 has a blade trailing edge 236 on the outlet side, and there is a middle curve 238 between the upper edge curve 234 and the lower edge curve 235. In FIG. 2B, from the perspective of the r_θ plane coordinates, there may be a fan-shaped channel width 237 between the two blades 23, but the upper edge curve 234 and the lower edge curve 235 do not overlap, especially the leading edge of the blade. The blade 23 near 232 has a three-dimensional twisted blade portion 233. The twisted blade 233 forms an arc and extends axially toward the entrance. The upper edge curve 234 and the lower edge curve 235 closer to the blade exit gradually approach each other. . In the streamline development diagram of FIG. 2C, the β angle represents the three-degree spatial angle of the blade 23. At the blade entrance position (m is close to 100%), the upper edge curve 234 and the lower edge curve 235 have different β angles, so the arc The front edge 232 of the curved blade spans between the two curves to form a curve line element 239a, which is an arc parallel to the front edge 232 of the blade. At the exit of the blade, the upper edge curve 234 and the lower edge curve 235 gradually approach. The curved element 239a gradually changes from an arc to a straight line. The conventional technology calls such a structure as a 3-dimensional blade curved surface 239.

Referring to Figure 2D, the upper edge curve 234 and the lower edge curve 235 of the 3D blade are composed of a plurality of arcs connected together. The center position of each arc is different and the radius is also different. In the mold slider with a fan-shaped runner width of 237 When taken out in the radial direction, it interferes with the molded blade 23.

3A, 3B, and 3C, where FIG. 3A shows a schematic side sectional view of a conventional impeller without an upper cover plate and with a 2.5-dimensional blade curved surface, FIG. 3B shows a schematic top view of the impeller in FIG. 3A, and FIG. 3C Draw the streamline development view of the 2.5-dimensional blade in Figure 3A. The blade 33 in FIG. 3A is set on the rear cover 32. The meridian width 331 of the blade 33 is gradually reduced from the widest entrance width B31 of the blade 33 to the narrowest exit width B32 of the blade 33. The rear cover 32 has a The inner surface 321, the constituent elements of the inner surface 321 on the r_z plane are arcs, so that the inner surface 321 is an inner convex cone. On the r_z plane (meridian), the entrance of the blade 33 has a blade leading edge 332, and the blade 33 is moving away from it. The rear cover plate 32 has an upper edge curve 334 on one side, the blade 33 has a lower edge curve 335 on the side where the rear cover plate 32 is combined, and the arc-shaped blade 33 has a rear edge 336 on the outlet side, and the upper edge curve 334 is connected to the lower edge curve 335. The edge curve 335 also has a middle curve 338 in the middle. In FIG. 3B, from the point of view of the r_θ plane coordinates, there may be a fan-shaped channel width 337 between the two blades 33, and the upper edge curve 334 and the lower edge curve 335 do not overlap, especially the leading edge 332 of the blade. The nearby blade 33 has a 2.5-dimensional twisted blade 333, which is straight and extends axially toward the entrance. At the entrance of the blade 33, the straight blade leading edge 332 spans between the upper edge curve 334 and the lower edge curve 335 to form a blade curved surface 339. The blade curved surface 339 is composed of linear elements 339b, which is called this in the prior art. The structure is a 2.5-dimensional blade surface.

In the conventional technology, the front cover and the blade are integrally formed when the 2.5-dimensional impeller is manufactured. The sliding block of the mold in the fan-shaped runner is divided along the direction of the straight element of the blade curved surface, and there is no interference problem. The front cover and the blade After forming, the hot melt or welding column and the back cover are combined to form a complete impeller. However, the upper edge curve 334 and the lower edge curve 335 of the 2.5-dimensional blade are composed of multiple curves, so the mold at the fan-shaped runner width 337 is slippery. When the block is split in the radial direction, it will still interfere with the formed blade, but the blade surface of the 3D twisted blade is composed of curve elements. If the mold slider at the fan-shaped runner width 337 is along the curve element of the blade surface The direction split will still interfere with the blade, so it cannot be molded in the same mode. Moreover, the rear cover is a power transmission element. Although thermal melting or welding can be used to combine the blade with the blade, it is still not integrated in a single process. There are still seams or structural discontinuities between the rear cover and the blades, resulting in weak structural strength and unable to withstand high temperature (for example, 200°C) and high load conditions.

In summary, a high-efficiency plastic impeller must have a front cover, a rear cover, and three-dimensional twisted blades, and must overcome the difficulties of manufacturing and molding.

In addition, traditionally, metal pumps have to be made into 3-dimensional curved blades with a front cover and a rear cover. Generally, the lost foam casting process or sheet metal parts are used to make various parts and then welded together. It is a fairly mature technology. Traditionally, there are several conventional techniques for making a closed 3-dimensional blade for a pump made of plastic material:

1. Use a 5-axis processing machine to carve a whole piece of plastic into an impeller with a 3-dimensional blade curved surface. However, this method will cause a lot of material waste and high processing costs, the width of the flow channel is narrow or the blade has a highly twisted shape, etc. The situation is not suitable to adopt such a processing method;

2. Use a 5-axis processing machine to carve a whole piece of plastic into an impeller with a 2.5-dimensional blade curved surface. Although it is easier to use flank milling than the previous method, this processing method will still cause A large amount of material waste and high processing cost, and the linear element of the blade surface reduces the distortion of the blade, and also reduces the pumping efficiency, so it still cannot fully meet the flow field requirements;

3. After the three parts of the impeller's front cover, multiple blades and rear cover are respectively molded and produced by molds, they are then assembled by ultrasonic or thermal welding. However, the blades, front cover and The back cover is not integrally formed in a single manufacturing process. There are seams or structural discontinuities between the components, resulting in weak structural strength and easy to use in high working temperature (such as about 200°C) or high load applications damage;

4. Divide the entire set of impeller twisted blades into two groups. On the front cover and the rear cover, some of the blades are produced in one piece. Most of the blades are even-numbered and divided into half, and then combined into the impeller by ultrasonic or welding. Although the sector width space between the blades has been increased, the twisted blades at the leading edge of the blade cannot be demolded directly in the axial or radial direction. A slider demolding mechanism is still required, and such a design has Half of the blades are only connected by ultrasonic or hot melt, and there is still the problem of weak structural strength and easy damage to high temperature (for example, 200°C) and high load applications;

5. The two-dimensional blade geometry is used to replace the three-dimensional twisted blades, and a simple arc line is used to replace the changing flow field streamlines, thereby allowing the mold slider to be smoothly taken out, but the two-dimensional blade pump The pump performance is low, which reduces the efficiency and cannot meet the EU's pump energy efficiency requirements;

6. In addition, the industry uses the method of lost foam to form the impeller, but the lost foam cannot be reused, and additional chemicals or heating must be used to decompose the lost foam core, which leads to complicated manufacturing processes and increased costs, which does not meet the needs of economic production;

7. In addition, the industry has layered the mold sliders in the runner and changed it to a set of runner mold sliders composed of a plurality of sliders, so that the mold sliders can be taken out from the runner in sequence. During the process, the mold slider taken out later can be taken out without hindrance by using the space made by the mold slider taken out first, but this method is only suitable for large runner width, large flow, low lift, and medium-to-high specific rate. This type of pump model has enough space to layer the mold slider. In addition, the demolding process of this method is complicated, and the design of the ejection mechanism is complicated, which increases the production cost.

Below, some existing published references on impeller manufacturing are listed.

Reference 2 (Chinese Patent CN 103128974 A)

Reference 2 is about the production process of a plastic closed impeller. It is pointed out that in order to facilitate the demolding of the conventional technology, the single arc of the pump impeller blade will reduce the efficiency of the impeller. The use of double arc blades in the closed impeller can improve the efficiency. However, the plug of the impeller mold cannot be removed, the impeller cannot be pressed, and an integral impeller cannot be produced. Reference 2 proposes to divide the front cover and the rear cover into two sets of molds, and then use the plastic screw combination, but Reference 2 does not mention how to produce a 3-dimensional twisted blade. The diagram in Reference 2 also shows its blade mold. For the axial unidirectional demolding and separation, it is only suitable for two-dimensional blades. Reference 2 also does not specify the reliability of using plastic screw combined blades instead of integral molding, and whether it can be applied to high temperature and high load occasions.

Reference 3 (Chinese Patent CN 104131995 A)

Reference 3 relates to a method for manufacturing a water pump impeller and a water pump. It is proposed to use a movable mold and a static mold to manufacture the impeller by injection, die-casting, or extrusion. However, Reference 3 points out that because the mold slider is not used, the impeller is The back cover will form a gap, which will affect efficiency. If inserts are used to fill the gap on the rear cover of the impeller, efficiency can be improved. However, the power transmission of the impeller in Reference 3 is to apply torque to the shaft hole and the rear cover by the shaft center, due to the huge gap in the rear cover. There is only a small area near the shaft hole. The connection between the rear cover and the blades needs to have the mechanical structure strength for pumping power transmission. Reference 3 shows that the connection position of the rear cover and the blades is a small radius area on the side of the shaft hole. It needs to bear a large torque load, and the area of the rear cover must be limited to the impeller suction port for demolding. This will make Reference 3 only suitable for centrifugal pumps with larger flow and lower head (mid-to-high specific speed).

Reference 4 (Chinese Patent CN 105179304 A)

Reference 4 is about a plastic anticorrosive wear-resistant pump and its impeller forming mold. It points out that the efficiency of plastic centrifugal pumps is generally lower than that of metal pumps, mainly because of the high efficiency of the centrifugal pump impeller, which requires the axial and radial direction of the impeller flow path. The plastic impeller must have a degree of distortion that conforms to the hydraulic model. In Xizhi’s compression molding technology, the mold is difficult to get out of the flow channel with a large degree of distortion. The metal impeller formed by the casting process can be crushed. Prolapse. Reference 4 proposes an impeller mold that can produce plastic 3-dimensional twisted blades, but the impeller runner block (shaped block) proposed in Reference 4 is divided into three groups, which must be taken out in order, which will cause complicated demolding engineering and production The cost is increased, and it is difficult to design an automatic demoulding mechanism, which cannot meet the needs of economic production.

Reference 5 (Chinese Patent CN 107471547 A)

Reference 5 is about the manufacture of centrifugal impeller molds. It proposes a mold mechanism design for the centrifugal fan impeller. The sliding block (mold core) in the impeller runner is divided into two groups, and the linkage mechanism is designed to make it possible to produce in r_z The surface has an impeller with varying widths, but generally the length of centrifugal fan blades is shorter than the length of the pump blades. Reference 5 also shows that its embodiment is a two-dimensional blade. Reference 5 also mentions the slider (mold core) in the impeller flow channel. ) The exit and entry paths are straight lines, which shows that the blade design suitable for the mold mechanism is not suitable for the 3-dimensional twisted blades required by the centrifugal pump.

Reference 6 (Chinese Patent CN 107092763 A)

Reference 6 is about the three-dimensional design of turbomachinery impellers with castability. Reference 6 explains that one of the important ways to improve the efficiency of various rotating fluid machinery is the three-dimensional design of the impeller, but it must be designed to be suitable for production. Reference 6 proposes a design method that takes into account the feasibility evaluation of manufacturing for the metal casting 3D impeller, but Reference 6 does not propose a manufacturing plan or manufacturing plan for a plastic pump impeller suitable for injection molding or transfer molding. Countermeasures.

Reference 7 (Chinese Patent CN 202209308 U)

Reference 7 is about a high-efficiency full ternary impeller. Reference 7 proposes a design of a 3-dimensional impeller to improve efficiency. However, Reference 7 shows that the new impeller design is made of aluminum alloy. It is shown that its impeller is a semi-open impeller, which is applied to a fan. Reference 7 does not provide an explanation for the manufacturing method.

Reference 8 (Chinese Patent CN 203009383 U)

Reference 8 is about a small-flow closed-type, fully milled ternary impeller, which belongs to the technical field of centrifugal compressors. Reference 8 proposes to add a ring groove on the front cover of the impeller to match the impeller inlet and outlet, and manufacture it by mechanical processing. The impeller can avoid the use of welding or jointing to combine the impeller, but the use of mechanical processing to engrave the blade flow channel will cause excessive manufacturing costs. Reference 8 does not provide an explanation for the production economy, and the front cover The annular groove will interfere with the flow in the flow channel and reduce the efficiency of the impeller.

Reference 9 (Chinese Patent CN 206753985 U)

Reference 9 is about a closed impeller. Reference 9 proposes a method of combining the front cover and the impeller. Through the design of the dovetail groove and the limit block, the shaft direction is fixed to prevent loose operation. Reference 9 does not Explain the material of the subject matter and the production method of the 3-dimensional blade runner.

Reference 10 (Patent WO2007/046565 A1)

Reference 10 proposes an integrated injection molding strategy for pump impellers for automotive cooling cycles. Reference 10 mentions that integrated injection molding impellers can improve blade efficiency and improve impeller reliability. However, the diagram in Reference 10 shows that its blades are two-dimensional blades. The patent content does not describe the production method of the plastic impeller with the 3-dimensional blade flow channel.

Reference 11 (Chinese Patent CN 102264525 A)

Reference 11 is about the injection molding method of pump impeller and pump impeller. Reference 11 points out that the flow path of the impeller will have undercut, that is, the side near the inlet of the impeller is connected with the pump inlet, and the undercut will hinder the flow path. To take out the mold core in the radial direction, the conventional technology must rely on the lost mold core or assemble multiple parts to form the impeller. In order to reduce the cost, Reference 11 proposes a method of taking out the mold slider in the runner of the centrifugal pump impeller. It can be reused to replace the lost mold core. First, take out a part of the mold core radially to make the runner of the impeller make room, and then take out the mold cores with undercuts in sequence. Reference 11 even proposes an optimized embodiment. Design a set of linkage mechanism to take out several mold cores together. However, if there is no automatic demolding mechanism, manual demolding will cause complicated demolding engineering, increase production costs, and fail to meet economic production requirements. If you use reference 11 To propose a linkage mechanism, there must be enough flow passage space, especially the axial width, to design the guiding path. The axial width of the impeller flow passage and outlet of the centrifugal pump will vary according to the pump type, and it is usually a small flow. , The model with high head (low specific speed) has a small outlet width, even only a few millimeters, and it is impossible to divide the mold cores into groups, and it is impossible to design the guiding mechanism. The model with large flow and low head (mid-to-high specific speed) In order to achieve higher efficiency with large blade distortion, the mold core must be divided in the axial direction and the meridian plane, the number of mold cores will increase, and the difficulty of designing the ejection mechanism will also increase.

Reference 12 (Patent WO2014/139578 A1)

Reference 12 is about a pump designed to transport liquids containing impurity particles, such as sand-containing water. Such liquids will cause impeller wear. Therefore, it is necessary to choose wear-resistant impeller materials. Reference 12 uses softer materials. For example, rubber is used as the wetted material of the impeller to resist abrasion. At the same time, the rubber material is elastic and easily deformed to make the mold slider in the impeller runner easy to take out. However, this reference 12 limits the impeller material to rubber with high elasticity. This type of material also limits the scope of application of the pump, especially high temperature (such as 200°C) and high load operating conditions. The wetted material of plastic pumps must usually be made of fluoroplastics, and the impellers of pumps without shaft seals must have The mechanical strength to resist the axial thrust load and must maintain contact friction or a very small gap with the suction side of the pump casing to reduce internal leakage loss. The temperature of the impeller made of rubber depends on the material, and generally cannot reach 200 ℃, and because of the elasticity rate High, it will be deformed to transmit power in the application, which cannot meet the application conditions of shaft-seal pump.

Reference 13 (Taiwan Patent TW 201640027 A)

Reference 13 is about centrifugal impellers used in fluid-operated pumps and the manufacturing method of the impeller. Reference 13 divides the impeller into two groups, the front cover and half the number of blades, the rear cover and half the number of blades, and use Positioning holes and ultrasonic waves combine the front and rear cover plates and the blades. This method only increases the production mold space between the blades. However, reference 13 does not explain how the twisted section of the blade at the central suction port of the impeller separates the mold from the finished blade. The impeller in reference 13 still has half the number of blades that are not integrally connected with the back cover plate responsible for power transmission, and are only combined by ultrasonic welding or chemical glue, screws, etc., that is, the impeller in the embodiment of reference 13 will Half of the impeller load is only transmitted by the combination of the blade and the cover plate with a positive contact surface. For plastic materials, there are mechanical strength structural problems under high temperature (such as 200 ℃) and high load. Reference 13 does not apply to this type of application. The reliability of the occasion is presented.

Reference 14 (US Patent US 2018/0243955A1)

Reference 14 relates to a method of manufacturing an impeller, using an injection molding method, but the twisted blades of the impeller are located on the outer edge of the rear cover in the mold, and are only connected to a small part of the rear cover, so they do not overlap with the rear cover. A mold slider is required. After injection, the blade is turned and the rear cover is clamped and connected to form an impeller. Although reference 14 allows the blade shape to be produced without restriction, it can produce better impeller efficiency, but reference 14 proposes The blades connected to the rear cover cannot make the impeller bear high torque load, so it is only suitable for low-power equipment. Reference 14 also shows that its technical field belongs to low-power applications such as automotive cooling fans.

Reference 15 (US Patent US 10016808 B2)

Reference 15 is about the structure of an evaporative mold core used to produce a 3-dimensional twisted impeller made of metal or plastic. The evaporative mold core is decomposed by chemicals or heat after the impeller is poured or injection molded. The manufacturing process is complicated and costly, which does not meet the needs of economic production.

Reference 16 (European Patent EP 0734834A1)

Reference 16 is about the mold structure of a closed plastic impeller, which is used to produce an integrated impeller. The upper and lower two pieces are combined with the radially extracted slider core and mold mechanism, and the impeller is produced by the injection molding method, but reference 16 The axially separated mold is not used, so it is impossible to manufacture a three-dimensional twisted blade. The drawing in Reference 16 also shows that the impeller has a two-dimensional structure, so it is difficult to achieve high efficiency requirements.

The present invention proposes a method for manufacturing a three-dimensional plastic impeller that can be molded into a centrifugal pump. The rear cover of the impeller includes an annular outer rear cover and an inner rear cover, and the annular outer rear cover has a first through hole. The front cover of the impeller includes an annular outer front cover and an inner front cover. The annular outer front cover has a second through hole. The front end of each blade is a twisted blade and is located in the first through hole and the annular outer rear cover. Between the second through holes of the ring-shaped outer front cover, the ring-shaped outer front cover has an inner surface, and its constituent elements on the r_z surface can be arcs; the ring-shaped outer rear cover has an inner surface, which is on the r_z surface The constituent elements of can be arcs. The manufacturing method is realized by using a twisted blade mold and an impeller outlet mold. The twisted blade mold can pass through the first through hole and the second through hole to form the twisted blade of the blade by a simple method of forming a fixed mold and a movable mold. The twisted blade The central part of the front cover and the rear cover are arranged in a ring shape and suspended between the first through hole and the second through hole. The difficulty of ejecting the mold after the twisted blade is formed is greatly reduced; at the same time, the impeller exit mold is used to The rest of the integrally formed blades except for the twisted blades include the annular outer rear cover that bears power transmission; the second through hole of the annular outer front cover and the first through hole of the annular outer rear cover can use other supplementary parts (such as The inner front cover and the inner rear cover) can be used to make up these supplementary parts. These supplementary parts can be formed by simple molds, and then combined with the ring-shaped outer rear cover and the ring-shaped outer front cover by heat melting or welding columns to form a complete Impeller, in which torque transmission can be directly transmitted to the load-bearing blades via the annular outer rear cover.

The present invention provides a three-dimensional plastic impeller for centrifugal pumps that can be produced by mold molding. Each blade includes a front end and a rear end that are connected to each other. The front end includes a first upper edge curve and a first lower edge curve. , The rear end includes a second upper edge curve and a second lower edge curve. The front end of each blade is the aforementioned twisted blade. The rear cover includes an annular outer rear cover and an inner rear cover. The annular outer rear cover It has a first through hole; the front cover includes a ring-shaped outer front cover and an inner front cover, the ring-shaped outer front cover has a second through hole; the front end of each blade is located at the first of the ring-shaped outer rear cover Between the through hole and the second through hole of the ring-shaped outer front cover; the rear end of each blade, the ring-shaped outer rear cover and the ring-shaped outer front cover are integrally formed at one time in the same molding step. The annular outer rear cover is used to transmit torque to these blades. The inner front cover is installed in the second through hole, and the inner rear cover is installed in the first through hole to join the front ends of the blades, thereby forming a complete with the blades, the annular outer rear cover and the annular outer front cover. impeller.

The improvement of the plastic centrifugal impeller structure of the present invention mainly aims to provide a mold that can be mass-produced to reduce manufacturing costs, so that the centrifugal blade can achieve high efficiency performance with a three-dimensional curved surface geometry, and can be suitable for high temperature (for example, 200°C) and high temperature. Load operating conditions.

When the centrifugal impeller of the present invention is formed, the annular outer rear cover of the rear cover is formed together with each blade at the rear end of the impeller, so that torque transmission can be reliably transmitted to all through the annular outer rear cover of the rear cover. On the leaves.

The blade angles of the second upper edge curve and the second lower edge curve on the blade are different, so there is no overlap with the streamline expansion of the blade. In this case, the two slider mold cores can be used to extract radially in order. Or design the ring-shaped outer front cover plate and the ring-shaped outer rear cover plate to be parallel to each other on the rz surface, and the impeller outlet mold can be slid out from the radial direction with a single simple slider.

When the second upper edge curve on the blade overlaps the second lower edge curve, the impeller outlet mold can be formed directly without using a slider mold, and then assembled and combined with the front cover plate and the inner and rear cover plates by hot melt or welding column A complete 3D plastic impeller, because the front cover only bears the pressure difference of the fluid and provides the overall strength of the impeller after molding, so the front cover will not have the problem of loosening due to high temperature and high load.

Roughly speaking, the mold for producing the impeller is divided into two components. The first component is the twisted blade mold, which is used to form the three-dimensional twisted blade at the entrance of the impeller. The twisted blade mold can have a fixed mold and a movable mold, and a fixed mold and a movable mold can be used. The ejection mold is drawn out in the opposite direction from the first and second through holes of the annular outer front cover and the annular outer rear cover in the axial direction; the second component is the impeller outlet mold, which is used to form the outer runner of the impeller, with and outside The sliders or slider groups with the same number of runners can be drawn out from the runner curve in the radial direction. The annular outer front cover, the outer rear cover and each blade are integrally formed in the same forming step, or only the blades and the outer rear cover are formed in the same forming step.

The manufacturing method and structure of the 3-dimensional plastic impeller of the centrifugal pump disclosed in the present invention can at least achieve the following effects: 1. All parts can be produced by molds, and can be automatically demolded by machines, which has production value; 2. .Twisted blades can be made by demolding and separating the fixed mold and the movable mold, and the 3-dimensional twisted blade geometry helps to improve the pumping performance; 3. The blades and the annular outer rear cover are integrally formed in a single process step, with High structural strength, the rear cover directly transmits torque to the blades, which helps the impeller run at high operating temperatures (such as about 200°C) or high-load applications without being easily damaged.

The above description of the disclosure of the present invention and the description of the following embodiments are used to demonstrate and explain the spirit and principle of the present invention, and to provide a further explanation of the scope of the patent application of the present invention.

The detailed features and advantages of the present invention will be described in detail in the following embodiments. The content is sufficient to enable anyone familiar with the relevant art to understand the technical content of the present invention and implement it accordingly, and according to the content disclosed in this specification, the scope of patent application and drawings. In this way, anyone who is familiar with the relevant art can easily understand the purpose and advantages of the present invention. The following examples further illustrate the viewpoints of the present invention in detail, but do not limit the scope of the present invention by any viewpoint.

In addition, the embodiments of the present invention will be disclosed in the following drawings. For clear description, many practical details will be described in the following description. However, it should be understood that these practical details are not intended to limit the present invention.

Moreover, for the purpose of neatness of the drawing, some conventionally used structures and elements may be drawn in a simple schematic manner in the drawing. In addition, some of the features in the drawings of this case may be slightly enlarged or their scales or sizes may be changed to achieve the purpose of facilitating the understanding and viewing of the technical features of the present invention, but this is not intended to limit the present invention. The actual size and specifications of the product manufactured in accordance with the content disclosed in the present invention should be adjusted according to the requirements during production, the characteristics of the product itself, and the content disclosed in the following in conjunction with the present invention, and it is hereby stated.

The first embodiment

First, please refer to FIGS. 4A to 4C and FIG. 5. FIG. 4A is a side sectional view of the impeller 5 of the first embodiment of the present invention, FIG. 4B is a schematic top view of the impeller 5 of FIG. 4A, and FIG. 4C is shown FIG. 4A is a streamline development view of the blade 53, and FIG. 5 is a schematic cross-sectional view of the impeller 5 in the first embodiment of the present invention. This embodiment proposes a plastic impeller 5 which is used for centrifugal pumps and has a three-dimensional flow channel.

In this embodiment, the impeller 5 includes a plurality of blades 53, an annular outer rear cover (hub rim part) 521, a rear inner plate (rear inner plate) 522, and an annular outer front cover (shroud rim part). 511 and a front inner plate 512. Wherein, as shown in FIG. 5, the annular outer front cover 511 and the inner front cover 512 can jointly form a front cover (shroud) 51, and the annular outer rear cover 521 and the inner rear cover 522 can jointly form a rear Hub 52. In addition, as shown in FIG. 4A or 4F, the ring-shaped outer front cover plate 511 has an inner surface 5111, and its constituent element on the r_z plane is an arc; the ring-shaped outer rear cover plate 521 has an inner surface 5111. For the surface 5211, the constituent elements on the r_z plane are straight lines parallel to the r axis and constitute a plane. In other words, the inner surface 5211 is a two-dimensional disc plane.

Looking further, as shown in FIG. 4A or FIG. 4B, the annular outer rear cover plate 521 has a first through hole 5210, the annular outer front cover plate 511 has a second through hole 5110, and each blade 53 is at least partially suspended in the annular Between the second through hole 5110 of the outer front cover 511 and the first through hole 5210 of the annular outer rear cover 521.

In detail, for the blade 53, on the r_z plane (meridional) coordinates, the blade 53 is defined with a leading edge 532 near the suction port 54. The blade 53 is connected to a front edge of the annular outer front cover 511. A shroud edge 534 is defined on the side, a hub edge 535 is defined on the side of the blade 53 that joins the annular outer rear cover 521, and a rear blade is defined on the side of the blade 53 farthest from the suction port 54 A trailing edge 536, and a mean 538 is defined between the upper edge curve 534 and the lower edge curve 535. Looking further, in this embodiment, the blade 53 may include a front end 530a and a rear end 530b that are connected to each other. The front end 530a is the part of the blade 53 closer to the front edge 532 of the blade, and the rear end 530b is The part of the blade 53 closer to the rear edge 536 of the blade; it can also be said that the front end 530 a is the part of the blade 53 closer to the suction port 54, and the rear end 530 b is the part of the blade 53 farther from the suction port 54. Moreover, in this embodiment or other embodiments, the shape of the front end 530a is much more twisted than the rear end 530b. Therefore, the front end 530a is a three-dimensional twisted portion of the blade 53, and therefore can also be called Twist the blades. In addition, the front end 530a is where the blade 53 is located between the second through hole 5110 of the annular outer front cover 511 and the first through hole 5210 of the annular outer rear cover 521, or in other words, the twisted blade of the blade 53 is located on the annular outer front cover Between the second through hole 5110 of the plate 511 and the first through hole 5210 of the annular outer rear cover 521. In addition, the front end 530a is connected to the ring-shaped outer rear cover 521 and the ring-shaped outer front cover 511 via the rear end 530b.

On the other hand, the meridional width 531 of the blade 53 changes gradually from the widest blade entrance width B51 of the blade 53 to the narrowest blade exit width B52 of the blade 53. In addition, in FIG. 4B, from the point of view of the r_θ plane coordinates, there is a sector width 537 between the two blades 53, between the leading edge 532 of the blade, the upper edge curve 534 and the lower edge curve 535. Does not overlap. In particular, as shown in FIGS. 4A and 4B, taking the front end 530a and the rear end 530b of the blade 53 as a distinction, the upper edge curve 534 of the blade 53 may include a first upper edge curve 5341 and a second upper edge curve. 5342, the lower edge curve 535 of the blade 53 may include a first lower edge curve 5351 and a second lower edge curve 5352. In other words, the first upper edge curve 5341 and the first lower edge curve 5351 respectively refer to the upper edge curve 534 and the lower edge curve 535 are on the front end portion 530a, and the second upper edge curve 5342 and the second lower edge curve 5352 respectively refer to the upper edge curve 534 and the lower edge curve 535 on the rear end portion 530b. In this embodiment, only the second upper edge curve 5342 of the upper edge curve 534 is connected to the annular outer front cover 511, and only the second lower edge curve 5352 of the lower edge curve 535 is connected to the annular outer rear cover 521.

In this embodiment and other embodiments, the blade 53 is twisted. Therefore, the second upper edge curve 5342 and the second lower edge curve 5352 of the rear end 530b of the blade 53 are shown in the streamline development view of the blade (as shown in FIG. 4C) The upper edge does not overlap, and the blade angles of the first upper edge curve 5341 and the first lower edge curve 5351 on the front end 530a of the blade 53 are different, so the first upper edge curve 5341 and the first lower edge curve 5351 are in the blade 53 The streamline expansion diagram (as shown in FIG. 4C) does not overlap, and from the streamline expansion diagram, the first upper edge curve 5341 and the first lower edge curve 5351 on the front end 530a do not overlap with each other on the impeller 5. The situation is more obvious, so the front end 530a of the blade 53 exhibits a higher degree of twisting geometry than the rear end 530b.

Specifically, in the streamline development view of the blade 53 in FIG. 4C, it can be seen more clearly that the blade outlet angle β _{2 is the} same, and the closer to the suction port 54 (that is, the closer to the shaft center of the impeller 5), the upper edge curve 534 is aligned with the lower The greater the difference of the blade angle β of the edge curve 535, the greater the degree of blade twist, especially the blade 53 has a three-dimensional twisted front end 530a near the front edge 532 of the blade, so the front end 530a of this embodiment It cannot be produced with radial sliding sliders, but needs to be produced with a special demoulding method, the content of which will be detailed in the subsequent paragraphs.

Further, please refer to FIG. 4D, which shows a simple schematic diagram of the mold division of the mold used in the impeller of this embodiment. In this embodiment and other embodiments, the mold used to make the impeller 5 at one time can be divided into two units, as shown in the figure, the twisted blade mold M1 and the impeller outlet mold M2. The twisted blade mold M1 can be used to form a highly twisted front end 530a (ie, twisted blade) between the first through hole 5210 of the annular outer rear cover plate 521 and the second through hole 5110 of the annular outer front cover plate 511. In detail, the twisted blade mold M1 may include, for example, a fixed mold M11 and a movable mold M12. When the fixed mold M11 is matched with the movable mold M12, the front end 530a of the blades 53 can be formed, due to the upper edge curve 534 of the blade 53 The difference between the blade angle of the lower edge curve 535 at the front end 530a is relatively large (that is, the upper edge curve 534 and the lower edge curve 535 of the blade 53 at the front end 530a do not overlap. Therefore, the demolding method of the fixed mold M11 and the movable mold M12 of the twisted blade mold M1 is to separate the first through hole 5210 of the annular outer rear cover plate 521 and the annular outer front cover in the opposite axial directions. The second through hole 5110 of the board 511. Since the front end 530a (ie twisted blade) of each blade 53 is suspended between the second through hole 5110 of the annular outer front cover plate 511 and the first through hole 5210 of the annular outer rear cover plate 521, the fixed mold M11 and When the movable mold M12 is disengaged in the opposite axial direction, it will not interfere with the blade 53, the annular outer front cover 511, and the annular outer rear cover 521. Here, it should be stated that the present invention is not limited to the positions of the fixed mold M11 and the movable mold M12 and the structure thereon. For example, in other embodiments, the positions of the fixed mold M11 and the movable mold M12 and the above The structure is also interchangeable.

On the other hand, the difference in blade angle between the upper edge curve 534 and the lower edge curve 535 of the blade 53 at the rear end 530b is relatively small (that is, the upper edge curve 534 and the lower edge curve 535 of the blade 53 are at the rear end 530b. It can be seen from the development of the streamlines of the blades that the degree of non-overlapping is small. Even in some embodiments, the upper edge curve 534 and the lower edge curve 535 of the blade 53 are in the streamline of the blade at the rear end 530b. The expanded view can overlap each other. Therefore, the impeller outlet mold M2 can be formed by multiple radially sliding sliders or slider groups to integrally form the blade 53 except for the front end 530a (ie, the twisted blade). Section 530b).

As shown in FIGS. 4D and 4E, specifically, in this embodiment, the impeller outlet mold M2 may include multiple sets of sliders, which are used to form each runner outlet (referring to the rear end 530b of the blade 53 and the outer ring). The space between the front cover plate 511 and the annular outer rear cover plate 521), each sliding block group may include a first sliding block M21 and a second sliding block M22, at least a part of the first sliding block M21 and the second sliding block M21 At least a part of the slider M22 can be matched to form the inner surface 5211 of the annular outer rear cover 521, the inner surface 5111 of the annular outer front cover 511, and the rear end 530b of the blade 53, wherein the first slider M21 has a first A contact surface M211 is used to form the inner surface 5211 of the ring-shaped outer rear cover plate 521, and the second sliding block M22 has a second contact surface M221 for forming the inner surface 5111 of the ring-shaped outer front cover plate 511. In this embodiment, the constituent elements of the first contact surface M211 of the first sliding block M21 are straight lines and constitute a plane. Therefore, the inner surface 5211 of the ring-shaped outer rear cover 521 can be shaped as a plane whose constituent elements are straight lines. The constituent element of the second contact surface M221 of the second slider M22 is an arc, so the second contact surface M221 is a convex tapered surface. In this case, the inner surface 5111 of the ring-shaped outer front cover 511 can be formed to form The element is the concave conical surface of the arc. Conversely, because the impeller 5 has the requirement that the constituent elements of the inner surface 5111 of the annular outer front cover plate 511 are arcs and the constituent elements of the inner surface 5211 of the annular outer rear cover plate 521 are straight lines, the aforementioned first sliding plate needs to be proposed. Block M21 and the second sliding block M22. Under this demand, the first sliding block M21 and the second sliding block M22 need to be demolded in sequence. Specifically, the blade 53 and the annular outer front cover 511 After the outer rear cover plate 521 is formed, the first sliding block M21 can be slid out radially first, and the second sliding block M22 can be easily slid out using the space made by the first sliding block M21 It will not cause interference problems with the rear end 530b of the formed blade 53, the annular outer front cover plate 511, and the annular outer rear cover plate 521.

However, the geometric shapes of the first slider M21 and the second slider M22 can be adjusted according to actual requirements, and the present invention is not limited to this. For example, as shown in FIGS. 4F and 4G, in a variation of the foregoing embodiment, the requirement of the impeller 5 is changed to the inner surface 5111 of the ring-shaped outer front cover plate 511. The constituent elements are straight lines and the inner surface of the ring-shaped outer rear cover plate 521 The constituent element of the surface 5211 is an arc. Correspondingly, the constituent element of the first contact surface M211 of the first sliding block M21 for forming the inner surface 5211 of the annular outer rear cover 521 is changed to an arc, so that the annular outer rear cover 521 The inner surface 5211 can be formed into an arc-shaped inner concave conical surface; and the second contact surface M221 of the second sliding block M22 for forming the inner surface 5111 of the ring-shaped outer front cover 511 is changed to a straight line. , So that the inner surface 5111 of the ring-shaped outer front cover 511 can be shaped into a plane whose constituent elements are straight lines. Similarly, the first slider M21 and the second slider M22 also need to be removed from the mold in sequence. Specifically, after the blade 53 is formed, the second slider M22 can be first slid out radially, and The first sliding block M21 can easily slide out using the space made by the second sliding block M22 after sliding out, without being contacted with the formed rear end 530b of the blade 53, the annular outer front cover 511, and the annular outer rear. The cover plate 521 causes interference problems. In addition, it is supplemented that the geometric configuration of the first slider and the second slider or the design of the matching surface between the two can be adjusted according to actual needs, and the present invention is not limited to this.

Further, referring to FIG. 5, the impeller 5 is assembled on a rotor 7. The impeller 5 includes a front cover 51, a rear cover 52 and the aforementioned plural blades 53. As mentioned above, the front cover 51 is composed of the aforementioned annular outer front cover 511 and inner front cover 512. 4A and 5, it can be seen that the inner front cover 512 is located within the range of the second through hole 5110 of the ring-shaped outer front cover 511, and the ring-shaped outer front cover 511 and the blades can be joined by heat fusion or ultrasonic waves. 53. In addition, the inner front cover 512 is provided with a wear ring mounting portion 512a for mounting the wear ring 8. The rear cover 52 is composed of the aforementioned annular outer rear cover 521 and inner rear cover 522. 4A and 5, it can be seen that the inner rear cover plate 522 is located in the range of the first through hole 5210 of the annular outer rear cover plate 521, and the annular outer rear cover plate 521 and the blades can be joined by heat fusion or ultrasonic waves. 53. In addition, the annular outer rear cover 521 is provided with a power transmission mounting portion 521a for mounting on the rotor 7.

As for the aforementioned inner front cover plate 512 and inner rear cover plate 522 of FIG. 5, both can be additionally produced by simple molds. The inner front cover plate 512 and the inner rear cover plate 522 and the first upper edge curves 5341 and 5341 of each blade 53 respectively The first lower edge curve 5351 is assembled and combined to form a complete 3-dimensional plastic impeller together with the annular outer front cover 511, the annular outer rear cover 521 and the blades 53. For example, please refer to FIGS. 6A to 6B, which are exploded schematic views of the parts of the impeller 5 before assembling in the first embodiment of the present invention. The inner front cover 512 can pass through the heat welding surface 512b and the heat welding surface 534a of the blade 53 The inner rear cover plate 522 can be seamlessly joined by heat melting or ultrasonic waves. The inner rear cover plate 522 can also be joined by the heat welding surface 522b of the inner rear cover plate 522 and the heat welding surface 535a of the blade 53 by heat melting or ultrasonic waves. Or, please refer to FIGS. 7A-7B, which are exploded schematic views of the impeller 5 of the present invention before being assembled from different perspectives. The inner front cover 512 can be combined with the welding post 534b of the blade 53 through the welding hole 512c and then heated and fused. The inner back cover 522 can also be combined with the welding hole 522a and the welding post 535b of the blade 53 in a pin manner and then heated and fused. It can be seen from this that the inner front cover 512 and the inner rear cover 522 are not integrally formed with the annular outer front cover 511, the annular outer rear cover 521 and the blades 53 in the same forming step.

Please refer to Figure 5, the power transmission of the pump is through the power transmission mounting part 521a and the annular outer rear cover 521 to the blade 53, because these three parts are formed into one body at one time in the same forming step, or in other words, the blade There is no joint between 53 and the annular outer rear cover plate 521 and its power transmission mounting portion 521a, or additional processing and joining part in the manufacturing process, so there is no joint or structural discontinuity, and the structural strength is high. Therefore, the annular outer rear cover plate 521 can directly receive the main load or power transmission of the pump, which helps to increase the application range of the pump. On the other hand, although the inner front cover plate 512 and the inner rear cover plate 522 are formed by simple molds and assembled into a complete impeller by means of heat melting or ultrasonic waves, the inner front cover plate 512 and the inner rear cover plate 522 are only responsible for The flow range of the limited fluid in the impeller 5 is not used as a structure that directly bears the main load or power transmission of the pump, so it will not affect the structural strength of the pump. As a result, the impeller 5 proposed in this embodiment can be applied to 200°C high temperature and high load applications.

Second embodiment

Please refer to Figures 8A to 8C and Figure 9. Figure 8A is a schematic side sectional view of the impeller 5 of the second embodiment of the present invention, Figure 8B shows a schematic top view of the impeller 5 of Figure 8A, and Figure 8C shows Figure 8A The streamline development view of the blade 5, FIG. 9 is a schematic cross-sectional view of the impeller 5 in the second embodiment of the present invention. As shown in the figure, the difference between this embodiment and the foregoing first embodiment is that the meridian width 531 of the blade 53 of the second embodiment gradually decreases from the blade entrance width B51 to the junction of the front end 530a and the rear end 530b, and the outer ring The front cover 511 has an inner surface 5111, and its constituent elements on the r_z plane are straight lines parallel to the r-axis and constitute a plane. In other words, the inner surface 5111 is a two-dimensional disc plane; the ring-shaped outer rear cover The plate 521 has an inner surface 5211, and its constituent elements on the r_z plane are straight lines parallel to the r-axis and constitute a plane. In other words, the inner surface 5211 is a two-dimensional disc plane. That is, the inner surface 5111 and the inner surface 5211 are parallel to each other, that is, the meridian width 531 from the junction of the front end 530a and the rear end 530b to the blade outlet width B52 remains unchanged, and the second upper edge curve 5342 It is substantially parallel to the second lower edge curve 5352 on the r_z plane. That is, in this embodiment, the meridian width 531 of the front end 530a of the blade 53 is tapered from the blade entrance width B51 to the blade exit width B52 along the middle curve 538, but the rear end 530b of the blade 53 is along the middle. The meridian width 531 of the curve 538 remains unchanged. As shown in Fig. 8B, the leading edge 532, the upper edge curve 534 and the lower edge curve 535 of the blade do not overlap at the front end 530a of the blade 53, and the upper edge curve 534 and the lower edge curve 535 do not overlap at the rear end 530b of the blade 53. Overlap.

In addition, in the streamline development view of the blade 53 in FIG. 8C, the exit angle of the blade is the same, from the junction of the front end 530a and the rear end 530b to the trailing edge 536 of the blade, the second upper edge curve 5342 and the second lower edge curve 5352 The difference of the blade angle β is within 10 degrees, so the production mold of this embodiment can only use a single mold slider to slide out of the mold in the radial direction at the impeller exit mold.

In detail, please further refer to FIG. 8D, which shows a simple schematic diagram of the mold parting of the mold used in the impeller of this embodiment. In this embodiment, since the annular outer front cover 511 and the annular outer rear cover 521 are substantially parallel to each other on the r_z plane (meridian plane), that is, the annular outer front cover 511 and the annular outer rear cover 521 are arranged in parallel with each other. The inner surfaces of the opposing surfaces are parallel to each other, so the space between the annular outer front cover plate 511 and the annular outer rear cover plate 521 does not gradually expand from the outside to the inside. Therefore, compared with the aforementioned FIG. 4D, the impeller of this embodiment The exit mold M2 can be changed to a single block of uniform thickness and radially extractable slider, and the single slider is used to form the inner surface 5211 of the annular outer rear cover plate 521 and the inner surface 5111 of the annular outer front cover plate 511. The constituent elements of the first contact surface M211 and the second contact surface M221 are both straight lines. By this configuration, the impeller outlet mold M2 can be radially slid out on the r_z surface (meridian surface). Moreover, since the annular outer front cover plate 511 and the annular outer rear cover plate 521 are parallel in the r_z plane (meridian plane) direction, the fan-shaped runner width 537 with a larger radius on the r_θ plane is also larger, so when the impeller exit mold is demolded There will be no obstacles or interference.

The third embodiment

Please refer to Figures 10A to 10C and Figure 11. Figure 10A is a schematic side sectional view of the impeller 53 of the third embodiment of the present invention, Figure 10B shows a schematic top view of the impeller 53 of Figure 10A, and Figure 10C shows Figure 10A The streamline development view of the blade 53. FIG. 11 is a schematic cross-sectional view of the impeller 53 of the third embodiment of the present invention.

The difference between this embodiment and the foregoing first embodiment is that the third embodiment is an impeller 5 with a lower specific speed for a pump with a lower flow rate and a higher head. The impeller 5 may not include the aforementioned annular outer front cover. The plate 511, and the blade 53 only needs a 3-dimensional twisted geometry at the front end 530a, and the rear end 530b of the blade 53 can be changed to a two-dimensional blade geometry. Specifically, the blade angles of the first upper edge curve 5341 and the first lower edge curve 5351 are different (that is, the first upper edge curve 5341 and the first lower edge curve 5351 remain non-overlapping in the streamline development view of the blade), However, the blade angles of the second upper edge curve 5342 and the second lower edge curve 5352 can be the same (that is, the second upper edge curve 5342 and the second lower edge curve 5352 can overlap each other in the streamline development view of the blade). The back cover 521 has an inner surface 5211, and its constituent element on the r_z plane is a straight line parallel to the r axis.

In addition, in the blade development view of FIG. 10C, the blade angle β of the rear end 530 b of the blade 53, the upper edge curve (shroud edge) 534, the middle curve (mean) 538 and the lower edge curve (hub edge) 535 are all the same.

Therefore, in this embodiment, the impeller outlet mold used to form the rear end 530b of the blade 53 does not need to be demolded in the radial direction, but the same as the twisted blade mold that forms the front end 530a of the blade 53 can be demolded in the axial direction. Way out. In detail, please refer to FIG. 10D. FIG. 10D shows a simple schematic diagram of the mold division of the mold used in the impeller of this embodiment. In this embodiment, since the impeller 5 may not include the aforementioned annular outer front cover 511, the side of the blade 53 away from the annular outer rear cover 521 is not shielded, and the rear end 530b of the blade 53 has a two-dimensional blade geometry. Therefore, the movable mold M12 of the twisted blade mold M1 for forming the twisted front end 530a (ie, the twisted blade) can be directly assembled with the impeller outlet mold M2 for forming the rear end 530b, and move away from the ring in the axial direction. The direction of the outer rear cover plate 521 is demolded without interference with the blade 53 in the process.

As for the part of the front cover 51, the outer front cover 511 and the inner front cover 512 can be formed into a single element using a simple mold, and then joined to the blade 53 by a suitable method such as heat melting or ultrasonic waves to form a composition. Complete impeller 5.

Fourth embodiment

Please refer to FIG. 12, which is a schematic cross-sectional view of a plastic impeller assembly according to a fourth embodiment of the present invention. The difference between this embodiment and the foregoing first embodiment is that the plurality of blades 53, the annular outer rear cover plate 521, and the annular outer front cover plate 511 of the impeller 5 are embedded with metal reinforcing members 55 to strengthen the rigidity of the overall structure and make The plastic impeller can still operate safely and stably under high temperature (200℃) and high load. It is supplemented that, in some other embodiments, the metal reinforcement 55 may not be provided in the annular outer front cover 511, that is, in this case, only the blades 53 and the annular outer rear cover 521 are provided in the impeller 5. Embed metal reinforcement 55.

It can be seen that the manufacturing method and structure of the 3-dimensional plastic impeller of the centrifugal pump disclosed in the foregoing various embodiments of the present invention can at least achieve the following effects: 1. All parts can be produced by molds, and can be automated by machines Demoulding, with production value; 2. The twisted blade (or the front end of the blade) can be made by separating the fixed mold from the movable mold, and the 3-dimensional twisted blade geometry can help improve the pumping performance; 3. The blades and the annular outer rear cover are integrally formed in a single forming step at one time, which has high structural strength. The annular outer rear cover directly transmits torque to the blades, which helps to keep the impeller at a high operating temperature (such as about 200 ℃) or high-load applications are not easy to damage.

Although the present invention is disclosed in the foregoing embodiments, it is not intended to limit the present invention. All changes and modifications made without departing from the spirit and scope of the present invention fall within the scope of the patent protection of the present invention. For the scope of protection defined by the present invention, please refer to the attached scope of patent application.

:流線座標 M1:扭曲葉片模具 M11:固定模 M12:可動模 M2:葉輪出口模具 M21:第一滑塊 M211:第一接觸面 M22:第二滑塊 M221:第二接觸面 β:葉片角 β₂ :葉片出口角度5: Impeller 7: Rotor 8: Wear ring 11, 51: Front cover 12, 22, 52: Rear cover 13, 23, 33, 53: Blade 54: Suction port 55: Metal reinforcement 131, 231, 331, 531: Meridian width 132, 232, 332, 532: Leading edge of blade 134, 234, 334, 534: Upper edge curve 135, 235, 335, 535: Lower edge curve 136, 236, 336, 536: Trailing edge of blade trailing edge 137, 237, 337, 537: sector width 138, 238, 338, 538: middle curve mean 233, 333: twisted blade 239, 339: blade surface 239a: curve element curve line element 339b: straight line element Straight line element 511: ring outer front cover 512: inner front cover 512a: wear ring mounting part 512b: heat welding surface 512c: welding hole 521: ring outer rear cover 521a: power transmission mounting part 522: inner rear cover 522a: welding hole 522b: thermal welding surface 530a: front end 530b: rear end 534a: thermal welding surface 534b: welding column 535a: thermal welding surface 535b: welding column 5110: second through holes 121, 221, 321, 5111: Inner surface 5210: first through hole 111, 5211: inner surface 5341: first upper edge curve 5342: second upper edge curve 5351: first lower edge curve 5352: second lower edge curve B11, B21, B31, B51: Blade entrance width B12, B22, B32, B52: blade exit width

: Streamline coordinates M1: Twisted blade mold M11: Fixed mold M12: Movable mold M2: Impeller outlet mold M21: First slider M211: First contact surface M22: Second slider M221: Second contact surface β: Blade angle β ₂ : Blade exit angle

FIG. 1A shows a schematic side sectional view of a conventional plastic impeller with two-dimensional blades. Fig. 1B is a schematic top view of the plastic impeller of Fig. 1A. Fig. 1C shows a streamline development view of the two-dimensional blade of Fig. 1A. FIG. 1D is a schematic diagram showing a three-dimensional expansion of the two-dimensional blade of FIG. 1A. FIG. 2A shows a schematic side sectional view of a conventional plastic impeller without an upper cover plate and with 3-dimensional blades. Fig. 2B is a schematic top view of the plastic impeller of Fig. 2A. Fig. 2C shows a streamline development view of the 3-dimensional blade of Fig. 2A. Fig. 2D is a schematic diagram of a multi-segment arc of the 3-dimensional blade curve of Fig. 2A. FIG. 3A shows a schematic side sectional view of a conventional plastic impeller without an upper cover plate and having a 2.5-dimensional leaf surface curve. Fig. 3B is a schematic top view of the plastic impeller of Fig. 3A. Fig. 3C shows a streamline development view of the 3-dimensional blade of Fig. 3A. 4A is a schematic side sectional view of the plastic impeller of the first embodiment of the present invention. Fig. 4B is a schematic top view of the plastic impeller of Fig. 4A. Fig. 4C shows a streamlined development view of the blade of Fig. 4A. FIG. 4D shows a simple schematic diagram of the mold splitting of the plastic impeller according to the first embodiment of the present invention. 4E is a partial enlarged schematic side sectional view of the plastic impeller according to the first embodiment of the present invention. 4F is a schematic side sectional view of a modification of the plastic impeller according to the first embodiment of the present invention. 4G shows a partial enlarged schematic side sectional view of a modification of the plastic impeller according to the first embodiment of the present invention. 5 is a schematic cross-sectional view of the plastic impeller assembly according to the first embodiment of the present invention. 6A to 6B are exploded schematic diagrams of different perspectives before the plastic impeller assembly of the first embodiment of the present invention. 7A-7B are the exploded schematic diagrams of the first embodiment of the present invention from different perspectives before the plastic impeller is assembled. FIG. 8A is a schematic side sectional view of the plastic impeller according to the second embodiment of the present invention. Fig. 8B is a schematic top view of the plastic impeller of Fig. 8A. Fig. 8C shows a streamlined development view of the blade of Fig. 8A. FIG. 8D is a simple schematic diagram of the mold splitting of the plastic impeller according to the second embodiment of the present invention. FIG. 9 is a schematic cross-sectional view of the plastic impeller assembly according to the second embodiment of the present invention. 10A is a schematic side sectional view of the plastic impeller of the third embodiment of the present invention. Fig. 10B is a schematic top view of the plastic impeller of Fig. 10A. Fig. 10C shows a streamlined development view of the blade of Fig. 10A. FIG. 10D shows a simple schematic diagram of the mold splitting of the plastic impeller according to the third embodiment of the present invention. 11 is a schematic cross-sectional view of the plastic impeller assembly according to the third embodiment of the present invention. 12 is a schematic cross-sectional view of a plastic impeller assembly according to a fourth embodiment of the present invention.

5: Impeller

53: blade

54: suction port

531: Meridian width

532: Leading Edge of Blade

534: Upper Edge Curve

535: lower edge curve

536: trailing edge

538: middle curve mean

511: Ring outer front cover

521: Ring outer rear cover

530a: Front end

530b: rear end

5110: second through hole

5111: inner surface

5210: first through hole

5211: inner surface

5341: First upper edge curve

5342: second upper edge curve

5351: First lower edge curve

5352: second lower edge curve

B51: Blade entrance width

B52: blade exit width

Claims (14)

A method for manufacturing a 3-dimensional plastic impeller for centrifugal pumps using mold molding: a rear cover plate of the impeller includes an annular outer rear cover plate and an inner rear cover plate, and the annular outer rear cover plate has a first pass The front cover plate of the impeller includes an annular outer front cover plate and an inner front cover plate, the annular outer front cover plate has a second through hole, and the plurality of blades of the impeller each have a twisted blade located in the ring Between the first through hole of the outer rear cover plate and the second through hole of the annular outer front cover plate; wherein a twisted blade mold and an impeller outlet mold are used to form the impeller; the twisted blade mold includes a fixed Mold and a movable mold, the fixed mold and the movable mold are used to form the twisted blades through the first through hole and the second through hole, wherein the twisted blades are formed on the front cover plate and the rear cover plate The central part is open and suspended in the central part; the impeller outlet mold is used to integrally form the remaining parts of the blades except the twisted blades and the ring-shaped outer rear cover plate that bears power transmission; wherein the ring-shaped outer front cover The second through hole of the plate and the first through hole of the ring-shaped outer rear cover plate are respectively provided for the inner rear cover plate and the inner front cover plate to be arranged in the form of thermal fusion or welding columns, thereby forming the impeller together. The manufacturing method according to claim 1, wherein the ring-shaped outer rear cover includes a power transmission mounting part. The manufacturing method according to claim 1, wherein the impeller outlet mold has a first sliding block and a second sliding block that can slide radially, and the first sliding block has a first contact surface for forming the The annular outer rear cover faces an inner surface of the annular outer front cover, and the second sliding block has a second contact surface for forming the annular outer front cover towards an inner surface of the annular outer rear cover , The first contact surface is a flat surface so that the inner surface of the ring-shaped outer rear cover is formed into a flat surface, and the second contact surface is an outer convex cone surface so that the inner surface of the ring-shaped outer front cover is formed It is a concave conical surface. The manufacturing method according to claim 1, wherein the impeller outlet mold has a first sliding block and a second sliding block that can slide radially, and the first sliding block has a first contact surface for forming the The annular outer rear cover faces an inner surface of the annular outer front cover, and the second sliding block has a second contact surface for forming the annular outer front cover towards an inner surface of the annular outer rear cover , The first contact surface is an outer convex cone surface so that the inner surface of the annular outer rear cover is formed into an inner concave cone surface, and the second contact surface is a flat surface so that the annular outer front cover The inner surface is formed into a flat surface. The manufacturing method according to claim 1, wherein an upper edge curve of each blade other than the twisted blade has the same blade angle as a lower edge curve, the impeller outlet mold and the movable mold are integrated, and the The annular outer rear cover plate and the blades are integrally formed at one time in the same manufacturing step. The manufacturing method according to claim 1, wherein the upper edge curve and the lower edge curve of each blade other than the twisted blade have different blade angles, and the annular outer front cover and the annular outer rear cover When the plates are parallel to each other, the impeller outlet mold has only a sliding block for radial sliding between any two adjacent two of the blades. A three-dimensional plastic impeller of a centrifugal pump that can be produced by mold forming, comprising: a front cover, a rear cover, and a plurality of blades, which are combined to form a fluid flow space in the impeller. The front cover and The rear cover plate is used to restrict the flow path, the rear cover plate is used to transmit torque to the blades, and each blade has a 3-dimensional twisted shape to improve pumping efficiency, and is characterized by: Each of the blades includes a front end portion, a rear end portion, an upper edge curve connecting the front cover plate, and a lower edge curve connecting the rear cover plate that are connected to each other, wherein the upper edge curve includes a first upper edge curve and A second upper edge curve, the lower edge curve includes a first lower edge curve and a second lower edge curve, the first upper edge curve and the first lower edge curve are located at the front end, the second upper edge curve And the second lower edge curve are located at the rear end, and the blade angle of the first upper edge curve is different from the blade angle of the first lower edge curve; The rear cover includes a ring-shaped outer rear cover and an inner rear cover. The ring-shaped outer rear cover has a first through hole, and the ring-shaped outer rear cover has a power transmission mounting portion to transmit torque to the blade; The front cover includes a ring-shaped outer front cover and an inner front cover, and the ring-shaped outer front cover has a second through hole; The front end of each blade is located between the first through hole of the annular outer rear cover plate and the second through hole of the annular outer front cover plate; The rear ends of the blades and the annular outer rear cover are integrally formed at one time in the same manufacturing step, and the rear ends of the blades are combined with the annular outer front cover; and The inner front cover and the inner rear cover are respectively installed in the second through hole and the first through hole to be combined with the front ends of the blades. The impeller according to claim 7, wherein the front cover is used to install a wear ring. The impeller according to claim 7, wherein the blade angle of the second upper edge curve of each blade is the same as the blade angle of the second lower edge curve. The impeller according to claim 7, wherein the annular outer front cover plate and the inner front cover plate are integrally formed. A centrifugal pump impeller, including: An annular outer rear cover plate; and a plurality of blades, the blades are arranged along the annular outer rear cover plate, wherein each of the blades has a twisted blade, the annular outer rear cover plate and the blades are in the same one at a time It is made by the forming step, and the twisted blades do not overlap with the annular outer rear cover. The impeller according to claim 11, wherein each of the blades includes a front end and a rear end connected to each other, the front end is the twisted blade and the annular outer rear cover is connected via the rear end, and each of the front ends The portion has a first upper edge curve and a first lower edge curve, and the blade angle of the first upper edge curve is different from the blade angle of the first lower edge curve. The impeller according to claim 12 further includes an inner rear cover plate, which joins the annular outer rear cover plate and the first lower edge curve of each blade. The impeller described in claim 11 further includes a metal reinforcement member embedded in the annular outer rear cover plate and the blades.

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