Impeller structure for assisting in reducing surge phenomenon

Abstract

The invention provides an impeller structure assisting in reducing the surge phenomenon. A plurality of impeller blades are symmetrically arranged in the circumferential direction of an impeller hub, and the impeller hub is fixedly connected with a pump shaft through a shaft sleeve; the shaft sleeve comprises an outer sleeve and an inner sleeve which are arranged in a nested mode, the outer sleeve is of a multi-section structure, and two labyrinth sealing structures are arranged on the outer sleeve. The inner sleeve is of a double-layer structure, the double-layer structure comprises a first inner sleeve and a second inner sleeve which are arranged in a spaced and sleeved mode, and a broadened flow channel is formed between the first inner sleeve and the second inner sleeve. The centrifugal impeller is adaptively mounted in a pump body, the centrifugal force of the impeller is reduced by reducing the number of impeller blades and increasing the diameter of an impeller hub, and the flow of the centrifugal impeller can be effectively reduced; the widened flow channel structure in the shaft sleeve can keep a flow channel of fluid unblocked, and noise reduction and surge reduction are facilitated. The shaft sleeve is of an inside and outside assembly structure, all sections outside the shaft sleeve are connected through labyrinth structures, and installation sealing performance and durability can be improved.

Description

Technical Field

[0001] The invention relates to an impeller pump, in particular to an impeller structure of a pump body which assists in reducing surge phenomenon, and belongs to the technical field of impellers. Background Art

[0002] A pump is a machine that transports fluids or pressurizes fluids. It transfers the mechanical energy of the prime mover or other external energy to the liquid, increasing the energy of the liquid. Pumps are mainly used to transport liquids such as water, oil, acid and alkali liquids, emulsions, suspensions and liquid metals. They can also transport liquid-gas mixtures and liquids containing suspended solids. Pumps can usually be divided into three categories according to their working principles: positive displacement pumps, dynamic pumps and other types of pumps. In addition to classification by working principle, they can also be classified and named by other methods, such as electric pumps and water turbine pumps according to the driving method; impeller pumps, gear pumps, single-stage pumps and multi-stage pumps according to the structure; boiler feed pumps and metering pumps according to the purpose; water pumps, oil pumps and mud pumps according to the nature of the transported liquid; linear pumps and traditional pumps according to whether there is a shaft structure.

[0003] Usually, there is a certain surge phenomenon during the operation of the pump. Specifically, in fluid mechanics, when the fluid is instantaneously compressed or its shape changes instantaneously, the pressure and flow rate in the fluid will increase at the same time, thereby causing air resistance vibration. This process will be repeated periodically, resulting in fluctuations in flow and pressure, increased mechanical vibration and noise, and a negative impact on the working efficiency and life of the pump. Among them, the impeller is the core component of the impeller pump. Not only is the hydraulic structure design of the impeller itself very important, but the rationality of its impeller structure will also reduce the impact of surge on the pump to a certain extent, thereby improving the overall performance of the pump. In this regard, this case proposes a new impeller structure that assists in reducing surge phenomena, so as to improve the application performance of the corresponding pump body. Summary of the invention

[0004] The purpose of the present invention is to solve the above-mentioned problem and provide an impeller structure that assists in reducing surge phenomenon, so as to reduce the surge problem existing in the pump body, stabilize the flow and pressure generated by the fluid, reduce mechanical vibration and noise, and improve the working efficiency of the pump.

[0005] The technical solution of the present invention is: an impeller structure that assists in reducing surge phenomena, including an impeller cover plate, an impeller hub and impeller blades, and several impeller blades symmetrically arranged along the circumference of the impeller hub, wherein: the impeller hub is fixedly connected to the pump shaft via a shaft sleeve; the shaft sleeve comprises an outer sleeve and an inner sleeve that are nested, the outer sleeve is a multi-section structure, and two sets of labyrinth sealing structures are provided on the outer sleeve; the inner sleeve is a double-layer structure, and the double-layer structure comprises a first inner sleeve and a second inner sleeve that are spaced apart, and a widened flow channel is formed between the first inner sleeve and the second inner sleeve.

[0006] Furthermore, in the above-mentioned impeller structure for assisting in reducing surge phenomenon, the number of the impeller blades is 2 to 4; and the distance between the impeller blades is 12% to 15% of the impeller radius.

[0007] Furthermore, in the above-mentioned impeller structure for assisting in reducing surge phenomenon, the surface of the impeller blades is coated with a nanocrystalline titanium nitride coating by laser cladding, with a single layer thickness of 2.5 to 4.5 μm and an overlap of 1.25 μm.

[0008] Furthermore, the impeller structure that assists in reducing surge phenomenon mentioned above, wherein: the process parameters of the laser cladding are: laser power is 1.5KW, scanning speed is 550mm / min, spot diameter is 6mm, powder feeding amount is 14.9g / min, and defocus amount is 33mm.

[0009] Furthermore, in the above-mentioned impeller structure for assisting in reducing surge phenomenon, the outer casing includes a first outer casing section, a second outer casing section and a third outer casing section which are arranged along the length direction of the outer casing.

[0010] Furthermore, the above-mentioned impeller structure that assists in reducing surge phenomena, wherein: a first labyrinth sealing structure for sealing the outer sleeve is provided between the first outer sleeve section and the second outer sleeve section, the first labyrinth sealing structure includes a pair of staggered first labyrinth teeth, the number of comb teeth of the first labyrinth teeth is 2 to 3 pieces, and sealant is filled between the two first labyrinth teeth.

[0011] Furthermore, the above-mentioned impeller structure that assists in reducing surge phenomena, wherein: a second labyrinth sealing structure for sealing the outer sleeve is provided between the second outer sleeve section and the third outer sleeve section, the second labyrinth sealing structure comprises a pair of staggered second labyrinth teeth, the number of comb teeth of the second labyrinth teeth is 4 to 8, and sealant is filled between the two second labyrinth teeth.

[0012] Furthermore, the above-mentioned impeller structure for assisting in reducing surge phenomenon, wherein: the first inner sleeve and the second inner sleeve are arranged at intervals by a plurality of supporting thin rods, the second inner sleeve is provided with a plurality of fine hole seats for positioning the supporting thin rods, and each of the fine hole seats is evenly distributed on the outer surface of the second inner sleeve around the axis of the second inner sleeve.

[0013] The present invention also provides a pump body, including a pump casing and a pump shaft constituting the pump body, and an impeller structure rotating in the pump casing and located at the front end of the pump shaft. The impeller structure is connected to the pump shaft using the above-mentioned sleeve structure, and centrifugal force is generated by the rotation of the impeller structure, thereby utilizing the impeller blades to drive the fluid to rotate at high speed, transferring mechanical energy to the fluid, thereby achieving the purpose of continuous fluid transportation by the pump body.

[0014] Compared with the prior art, after adopting the technical solution of the present invention, the number of impeller blades is reduced and the diameter of the impeller hub is increased to reduce the centrifugal force of the impeller, thereby effectively reducing the flow rate of the centrifugal impeller, which helps to reduce the surge phenomenon; the sleeve arranged between the impeller and the pump shaft is an internal and external assembly structure, and the sections outside the sleeve are connected by a labyrinth seal to improve the installation sealing and durability; a widening structure is provided between the two layers of inner sleeves inside the sleeve to keep the flow channel of the fluid unobstructed, which helps to reduce noise and surge phenomenon; in addition, the surface of the impeller blades is coated with a nanocrystalline titanium nitride coating by laser cladding, which extends the service life by enhancing the wear resistance of the blade surface. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a structural schematic diagram of the impeller of the present invention;

[0016] Figure 2 It is a side view of the impeller and the pump shaft of the present invention in an assembled state;

[0017] Figure 3 It is a cross-sectional schematic diagram of the impeller and the pump shaft of the present invention in an assembled state;

[0018] Figure 4 It is a structural schematic diagram of the shaft sleeve of the present invention;

[0019] Figure 5 is a schematic cross-sectional view of the shaft sleeve of the present invention;

[0020] Figure 6 It is a structural schematic diagram of the shaft sleeve of the present invention;

[0021] Figure 7 It is a structural schematic diagram of the outer sleeve of the present invention;

[0022] Figure 8 It is a structural schematic diagram of the inner sleeve of the present invention;

[0023] Fig. 9 It is an exploded schematic diagram of the shaft sleeve of the present invention.

[0024] The meanings of the reference numerals in the figure are as follows: 1-impeller cover plate, 2-impeller hub, 3-impeller inner hole, 4-keyway, 5-impeller blade, 6-shaft sleeve, 61-first outer sleeve section, 62-second outer sleeve section, 63-third outer sleeve section, 64-first inner sleeve, 65-second inner sleeve, 651-fine hole seat, 66-first labyrinth sealing structure, 67-second labyrinth sealing structure, 7-pump shaft, 8-support thin rod, 9-widening flow channel. DETAILED DESCRIPTION

[0025] The technical solution of the present invention is further described below in conjunction with the accompanying drawings to make it easier to understand and grasp. The impeller cover plate 1, impeller hub 2 and impeller inner hole 3 involved therein are all commonly used by ordinary technicians in the field, and there is no special requirement for them in this case.

[0026] In order to make the purpose, technical solution and advantages of the present invention more clear, the present invention is further described below in conjunction with specific examples, but it should not be understood that the protection scope of the above subject matter of the present invention is limited to the following examples. Among them, the materials or parts used are commercially available or homemade using methods known in the industry.

[0027] like Figure 1 to Figure 3 As shown, the present invention provides an impeller structure for assisting in reducing surge phenomenon, including an impeller cover plate 1, an impeller hub 2 and impeller blades 5, three impeller blades 5 are symmetrically arranged along the circumference of the impeller hub 2, and the blade distance between each impeller blade 5 is 12% of the impeller radius. The impeller hub 2 is provided with an impeller inner hole 3, and the impeller hub 2 is fixedly connected to the pump shaft 7 through a shaft sleeve 6. The impeller inner hole 3 is provided with a keyway 4, and the pump shaft 7 is further tightly fixed by the keyway 4, thereby improving the transmission efficiency of the impeller and preventing axial sliding, while reducing the stress concentration inside the impeller hub 2 and reducing the risk of its deformation, thereby improving the service life and safety.

[0028] According to the technical solution of the present invention, Figures 4 to 9 As shown, the shaft sleeve 6 includes an outer sleeve and an inner sleeve that are nested. The outer sleeve is a multi-section structure, and an assembled outer sleeve structure is adopted to replace the traditional integral outer sleeve structure, which not only effectively simplifies the processing mold and improves the demoulding efficiency, but also can be partially replaced and repaired, which is convenient for the long-term maintenance of the outer sleeve and saves the cost of replacing pipe materials; the outer sleeve is provided with two sets of labyrinth sealing structures to prevent the damage of the shaft sleeve 6 caused by the failure of a single set of seals, ensure that the shaft sleeve 6 maintains stable operation during the continuous operation of the impeller structure, and help reduce the cost of fluid transportation; moreover, the labyrinth sealing structure can effectively increase the connection strength of the assembled shaft sleeve 6, and can achieve the effect of an integral structure, thereby enhancing the stability of the shaft sleeve 6 connecting the impeller structure and the pump shaft 7, reducing the vibration of the pump body, and thus reducing the risk of surges. Figure 5 As shown, the inner sleeve is a double-layer structure, which includes a first inner sleeve 64 and a second inner sleeve 65 which are spaced apart. A widened flow channel 9 is formed between the first inner sleeve 64 and the second inner sleeve 65. The widened flow channel 9 can widen the fluid path to reduce surges while suppressing the noise generated by surges from continuing to propagate outward.

[0029] Preferably, in the above structure: the surface of the impeller blade 5 is clad with a nanocrystalline titanium nitride coating by laser cladding, with a single layer thickness of 3.5 μm and an overlap of 1.25 μm, wherein the process parameters of the laser cladding are: laser power of 1.5 KW, scanning speed of 550 mm / min, spot diameter of 6 mm, powder feeding amount of 14.9 g / min, and defocusing amount of 33 mm. The nanocrystalline titanium nitride coating has the advantages of high hardness, high temperature tolerance, corrosion resistance, etc., and improves the surface hardness and wear resistance of the impeller blade 5.

[0030] Specifically, the method for laser cladding the surface of the impeller blade 5 with a nanocrystalline titanium nitride coating comprises the following steps:

[0031] (i) preparing nanocrystalline titanium nitride, including titanium oxide doped with platinum group metal elements (such as palladium, iridium or ruthenium), wherein the mass percentage of the platinum group metal elements to the titanium oxide is 1:97, and the particle size of the titanium oxide is 38 μm, and the two are ball-milled and mixed, the speed of the ball mill is 400 rpm, the ball milling gas is an inert gas with a volume purity of 99.99%, and the mixing time is 18 minutes to obtain a titanium oxide mixed powder.

[0032] (ii) Nanocrystalline titanium nitride was prepared by treating titanium oxide mixed powder with reduction nitridation method. The synthesis time was 10 h. The prepared nanocrystalline titanium nitride powder was placed in a drying oven for drying. The drying time was 0.5 h.

[0033] (iii) The surface of each impeller blade 5 is thoroughly cleaned and cladding material is added to the surface of each impeller blade 5 .

[0034] (iv) The dried nanocrystalline titanium nitride powder is processed by synchronous powder feeding laser cladding equipment, and the surface treated impeller blades 5 are coated with nanocrystalline titanium nitride coating, and then the coated nanocrystalline titanium nitride coating is bombarded with supersonic alumina hard particles (particle flow rate 22g / s, working voltage 28V, bombardment time 25min) to form a metallurgically bonded nano-additive cladding layer.

[0035] Preferably, in the above structure: Figure 4 As shown, the outer sleeve includes a first outer sleeve segment 61, a second outer sleeve segment 62 and a third outer sleeve segment 63 arranged along the length direction of the outer sleeve. The assembled pipe segments are conducive to mold processing and fault replacement, and improve the convenience of maintenance.

[0036] Specifically, Fig. 9As shown, in the structure of the outer sleeve, a first labyrinth seal structure 66 for sealing the outer sleeve is provided between the first outer sleeve section 61 and the second outer sleeve section 62. The first labyrinth seal structure 66 includes a pair of staggered first labyrinth teeth, the number of teeth of the first labyrinth teeth is 2, and a sealant is filled between the two first labyrinth teeth. The sealant is one of silicone, butyl rubber and polyurethane. The first labyrinth seal structure 66 can effectively resist the instantaneous strong impact pressure generated when the impeller structure is in operation.

[0037] Specifically, in the structure of the outer sleeve, a second labyrinth seal structure 67 for sealing the outer sleeve is provided between the second outer sleeve section 62 and the third outer sleeve section 63. The second labyrinth seal structure 67 includes a pair of staggered second labyrinth teeth, the number of teeth of the second labyrinth teeth is 4, and a sealant is filled between the two second labyrinth teeth. The sealant is one of silicone, butyl rubber and polyurethane. The second labyrinth seal structure 67 improves the pressure resistance of the impeller structure and the ability to withstand high-speed centrifugal operation.

[0038] Preferably, in the above structure: the first inner sleeve 64 and the second inner sleeve 65 are spaced apart by a plurality of supporting thin rods 8 (i.e., the formed spacing space is the widened flow channel 9); the second inner sleeve 65 is provided with a plurality of fine hole seats 651 for positioning the supporting thin rods 8; each of the fine hole seats 651 is evenly distributed on the outer surface of the second inner sleeve 65 around the axis of the second inner sleeve 65; the supporting thin rod 8 can be plugged into the fine hole seats 651; the supporting thin rod 8 can be further stabilized by the fine hole seats 651, and the loosening of the supporting thin rod 8 caused by fluid impact can be effectively prevented.

[0039] In the technical solution of the present invention, the two sets of labyrinth seal structures and the widened flow channel 9 provided in the assembled sleeve 6 are the synergistic effects of these two aspects, which are the technical key of this case. The enhanced structural stability can effectively reduce the surge phenomenon. Figure 2 and Figure 3 The focus is on the sleeve 6 connecting the impeller structure and the pump shaft 7. Figures 4 to 9 The specific structure of the sleeve 6 is shown, and the provided assembled sleeve 6 is easy to disassemble and maintain. For the impeller cover plate 1 and the impeller hub 2 components, ordinary technicians in this field can make conventional settings according to the existing technology, and this case has no special requirements for their model selection and combined use.

[0040] In this way, the technical solution of the present invention is adopted to adapt the impeller structure to be installed in the corresponding pump body, which includes a pump casing and a pump shaft 7. The impeller structure rotates in its pump casing and is installed at the front end of the pump shaft 7. The centrifugal force is generated by the rotation of the impeller structure, so that the impeller blades 5 drive the fluid to rotate at high speed, and the mechanical energy is transmitted to the fluid, thereby achieving the purpose of continuous fluid transportation by the pump body.

[0041] From the above description, it can be found that compared with the prior art, after adopting the technical solution of the present invention, by reducing the number of impeller blades and increasing the diameter of the impeller hub at the same time, the centrifugal force generated when the impeller rotates can be effectively reduced, thereby achieving effective reduction of the impeller fluid flow rate during centrifugal operation, which helps to reduce surge phenomenon; the shaft sleeve arranged between the impeller and the pump shaft is an internal and external assembly structure, and the sections outside the shaft sleeve are connected by a labyrinth seal to improve the installation sealing and durability; a widening structure is provided between the two layers of inner sleeves inside the shaft sleeve to keep the flow channel of the fluid unobstructed, which helps to reduce noise and surge phenomenon; in addition, the surface of the impeller blades is coated with a nanocrystalline titanium nitride coating by laser cladding, which extends the service life by enhancing the wear resistance of the blade surface.

[0042] The technical scheme, working process and implementation effect of the present invention are described in detail above. It should be noted that what is described is only a typical example of the present invention. In addition, the present invention may also have many other specific implementation methods. Any technical scheme formed by equivalent replacement or equivalent transformation falls within the scope of protection required by the present invention.

Claims

1. An impeller structure for assisting in reducing surge phenomenon, comprising an impeller cover plate (1), an impeller hub (2) and impeller blades (5), wherein a plurality of impeller blades (5) are symmetrically arranged along the circumference of the impeller hub (2), characterized in that: The impeller hub (2) is fixedly connected to the pump shaft (7) via a shaft sleeve (6); the shaft sleeve (6) comprises an outer sleeve and an inner sleeve which are nested together, the outer sleeve being a multi-section structure, and having two sets of labyrinth sealing structures; the inner sleeve is a double-layer structure, comprising a first inner sleeve (64) and a second inner sleeve (65) which are spaced apart from each other, and a widened flow channel (9) is formed between the first inner sleeve (64) and the second inner sleeve (65).

2. The impeller structure for assisting in reducing surge phenomenon according to claim 1, characterized in that: The number of the impeller blades (5) is 2 to 4.

3. The impeller structure for assisting in reducing surge phenomenon according to claim 1, characterized in that: The blade distance of the impeller blades (5) is 12% to 15% of the impeller radius.

4. The impeller structure for assisting in reducing surge phenomenon according to claim 1, characterized in that: The surface of the impeller blade (5) is coated with a nanocrystalline titanium nitride coating by laser cladding, with a single layer thickness of 2.5 to 4.5 μm and an overlap of 1.25 μm.

5. The impeller structure for assisting in reducing surge phenomenon according to claim 4, characterized in that: The process parameters of the laser cladding are: laser power of 1.5 KW, scanning speed of 550 mm / min, spot diameter of 6 mm, powder feeding amount of 14.9 g / min, and defocusing amount of 33 mm.

6. The impeller structure for assisting in reducing surge phenomenon according to claim 1, characterized in that: The outer sleeve comprises a first outer sleeve section (61), a second outer sleeve section (62) and a third outer sleeve section (63) which are arranged along the length direction of the outer sleeve.

7. The impeller structure for assisting in reducing surge phenomenon according to claim 6, characterized in that: A first labyrinth sealing structure (66) for sealing the outer sleeves is provided between the first outer sleeve section (61) and the second outer sleeve section (62). The first labyrinth sealing structure (66) comprises a pair of staggered first labyrinth teeth, the number of teeth of the first labyrinth teeth being 2 to 3, and a sealant is filled between the two first labyrinth teeth.

8. The impeller structure for assisting in reducing surge phenomenon according to claim 6, characterized in that: A second labyrinth sealing structure (67) for sealing the outer sleeves is provided between the second outer sleeve section (62) and the third outer sleeve section (63). The second labyrinth sealing structure (67) comprises a pair of staggered second labyrinth teeth, the number of teeth of the second labyrinth teeth being 4 to 8, and a sealant is filled between the two second labyrinth teeth.

9. The impeller structure for assisting in reducing surge phenomenon according to claim 1, characterized in that: The first inner sleeve (64) and the second inner sleeve (65) are arranged at intervals via a plurality of thin supporting rods (8), and the second inner sleeve (65) is provided with a plurality of thin hole seats (651) for positioning the thin supporting rods (8), and each of the thin hole seats (651) is evenly distributed around the axis of the second inner sleeve (65) on the outer surface of the second inner sleeve (65).

10. A pump body, comprising a pump casing and a pump shaft (7) constituting the pump body, and an impeller structure rotating in the pump casing and located at the front end of the pump shaft (7), characterized in that: The impeller structure is the impeller structure according to any one of claims 1 to 9.

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