CN114076103A

CN114076103A - Wear-resistant design method of centrifugal mud pump

Info

Publication number: CN114076103A
Application number: CN202110511864.XA
Authority: CN
Inventors: 郭涛; 胡京招; 武永顶; 夏铖; 伍立说; 王文魁; 兰剑; 马源; 庄海飞; 王海荣
Original assignee: CCCC National Engineering Research Center of Dredging Technology and Equipment Co Ltd
Current assignee: CCCC National Engineering Research Center of Dredging Technology and Equipment Co Ltd
Priority date: 2021-05-11
Filing date: 2021-05-11
Publication date: 2022-02-22
Anticipated expiration: 2041-05-11
Also published as: CN114076103B

Abstract

An anti-wear method applied to a centrifugal mud pump is characterized in that: a guide vane is designed on an inlet anti-abrasion ring of the impeller, and the strategy of dividing the mud slurry in advance is adopted to conduct deviating flow guiding on the mud slurry, so that the head of the blade is prevented from bearing direct impact of the mud slurry; the guide vanes are arranged on an inlet anti-abrasion ring of the impeller, a plurality of guide vanes are uniformly distributed on the inner wall of the inlet anti-abrasion ring in the circumferential direction, and the guide vanes and the inlet anti-abrasion ring synchronously rotate along with the impeller; meanwhile, the guide vanes (2) on the inlet wear-resistant ring and the corresponding blades are divided into two bodies, and a spacing area B exists; meanwhile, a high-pressure flushing structure is designed on the blade (4), and is matched with the guide vane (2), the high-pressure flushing forms countercurrent jet flow from the blade head (4.1), a backpressure gradient is formed, so that the mud mortar deviates in advance, even the mud mortar vortex is prevented from being formed in the interval area B, and finally the blade head (4.1) is prevented from being abraded by mud impact.

Description

Wear-resistant design method of centrifugal mud pump

Technical Field

The application relates to a wear-resistant design method of a centrifugal mud pump (slurry pump).

Background

A dredge pump (also called a slurry pump) is a mechanical device which can continuously convey soil, gravel, crushed ore and other substances in a pumping mode, is commonly used in the fields of dredging and filling, mining machinery, sewage treatment and the like, and is mainly used for applying work to solid particle-water mixed substances such as silt, improving the mechanical energy of the solid particle-water mixed substances, conveying the solid particle-water mixed substances to a specified area through a pipeline, and is an essential key device in the field of dredging.

In consideration of various requirements such as convenience in assembly and disassembly, high lift, high efficiency and the like, a single-stage single-suction centrifugal pump is generally adopted as a dredge pump, and a closed impeller structure is generally adopted as an impeller. In the pump, fluid is horizontally sucked into the pump from a shaft end, then enters the rotating impeller to be converted into radial flow, is restrained in a flow passage defined by the front cover plate, the rear cover plate and the blades to rotate along with the impeller, is subjected to work by the blades in the process to have higher pressure and speed, then flows out of the impeller to enter a pressure expansion chamber, is subjected to speed reduction and pressurization in the pressure expansion chamber, converts part of kinetic energy into pressure energy, and finally flows out of an outlet of the pressure expansion chamber.

Different from the conventional water pump, the substances conveyed by the mud pump (figure 1) contain various irregular sharp solids, which can cause serious abrasion to the impeller which is a main acting part in the mud pump. The abrasion problem of the impeller of the dredge pump is still a difficult problem to be solved urgently. Effectively reduce the wearing and tearing of impeller and can prolong the life of impeller, practice thrift cost of maintenance. Meanwhile, the impeller structure which is as complete as possible is a necessary guarantee for stable operation of the dredge pump and efficient dredging construction. The main technical approaches for reducing the abrasion of the impeller are divided into two major directions of 'selecting abrasion-resistant materials' and 'improving the structure'.

Closest to the prior art:

at present, the structural design of the impeller of the dredge pump improves the flow in the impeller by reasonably selecting a blade inlet angle and a blade wrap angle, adopting the technical means of bending and twisting blade modeling and the like, and the structural technologies obtain good results on improving the abrasion, but have difficult breakthrough development. Aiming at the abrasion near the inlet and the outlet of the impeller, the dredge pump is generally provided with a suction port abrasion-proof ring at the inlet of the impeller, a shoulder blade abrasion-proof ring is arranged outside the outlet of the impeller (specifically, the shoulder blade abrasion-proof ring is arranged between a diffusion chamber and a pump cover to protect the connection part of the diffusion chamber and the pump cover), the abrasion-proof ring is tried to be replaced continuously, the whole impeller is prevented from being scrapped due to local damage at the part, but the abrasion of the head part of a blade, the end surface near the head part of the blade and the abrasion near the tail part of the blade are not targeted in a structural improvement technical scheme.

Disclosure of Invention

The application aims to disclose an anti-wear method to solve the problem that severe wear of a dredge pump mainly occurs at the inlet of an impeller and the head of a blade (mainly close to a large radius of a front cover plate).

The abrasion of the blade head is mainly impact abrasion, because the area (as shown in a part A of the figure 1) of the impeller inlet close to the front cover plate has larger circumferential speed, the volume of gravel and rock is larger, and thus, the solid with higher hardness can impact the position (as shown in a part A of the figure 1) under the action of inertia after entering the impeller; therefore, the abrasion on the end face near the blade head is mostly generated by vortex, the vortex is easy to appear in the near flow due to the shunting action of the blade head, and sand is repeatedly scraped in the vortex to cause abrasion.

In response to the above technical problem, the technical solution to be protected in the present application is:

an anti-wear method applied to a centrifugal mud pump is characterized in that:

a guide vane is designed on an inlet anti-abrasion ring of the impeller, and the strategy of dividing the mud slurry in advance is adopted to conduct deviating flow guiding on the mud slurry, so that the head of the blade is prevented from bearing direct impact of the mud slurry; the guide vanes 2 are arranged on an inlet anti-abrasion ring 1 of the impeller, the guide vanes 2 are uniformly distributed on the inner wall of the inlet anti-abrasion ring 1 in the circumferential direction, and the guide vanes 2 and the inlet anti-abrasion ring 1 rotate synchronously with the impeller;

meanwhile, the guide vanes (2) on the inlet wear-resistant ring 1 and the corresponding blades 4 are divided into two bodies, and an interval area B exists;

meanwhile, a high-pressure flushing structure is designed on the blade (4), and is matched with the guide vane (2), the high-pressure flushing forms countercurrent jet flow from the blade head (4.1), a backpressure gradient is formed, so that the mud mortar deviates in advance, even the mud mortar vortex is prevented from being formed in the interval area B, and finally the blade head (4.1) is prevented from being abraded by mud impact.

Further inject technical scheme, in the impeller, the quantity of flow guide vane 2 is unanimous with blade 4 quantity, and its position of setting is relative with blade 4, leaves the clearance each other.

Further limiting the technical scheme, the guide vane 2 is close to and opposite to the head of the impeller blade 4.

The technical scheme is further limited, a high-pressure water source and high-pressure sealing water between the front cover plate (3) of the impeller and the front pump cover and a lining plate (12) of the front pump cover are connected in the blade through a high-pressure flushing inlet pipe (13), flushing holes/grooves (6) are formed in the surface of the head portion (4.1) of the blade, high-pressure flushing water flows in from the surface of the head portion (4.1) of the blade through the flushing holes/grooves (6) and is ejected out, a backpressure gradient is formed in a gap area (B in figures 4 and 6) between the blade and the guide vane, and the high-pressure flushing water is ejected out along the tail portion (2.2) of the guide vane.

The flushing hole/groove (6) is communicated with the high-pressure sealing water through a water guide pipe (7). Namely, a pressure flushing mechanism is designed, the pressure flushing mechanism comprises a high-pressure flushing inlet pipe (13), a water guide pipe (7) and a flushing hole/groove (6), the outlet end of the high-pressure flushing inlet pipe (13) is high-pressure sealing water between an impeller front cover plate (3) and a front pump cover and a lining plate (12) of the front pump cover, and the high-pressure sealing water is connected with the flushing hole/groove (6) through the water guide pipe (7). The flushing hole/groove (6) is arranged on the surface of the blade head (4.1) so that high-pressure flushing water is sprayed out from the blade head (4.1) and forms countercurrent jet flow.

Drawings

FIG. 1 is a side view of a conventional dredge pump impeller;

FIG. 2 is a schematic 1/4 cross-sectional view of the dredge pump impeller assembly of example 1;

FIG. 3 is a schematic rear structure view of a vane wheel set and an inlet wear ring (installed with a guide vane) in embodiment 1;

FIG. 4 is a schematic diagram of the mechanism of the inlet wear ring (with guide vanes installed) in the impeller assembly of embodiment 1;

FIG. 5, embodiment 2 is a first side view of the dredge pump: the arrangement and the position of a high-pressure flushing structure are shown;

FIG. 6 illustrates the principle of the anti-wear effect of the flow guide vanes and the high pressure flush of the blade head in embodiment 2;

numerical labeling: 1. an inlet wear ring; 2. a guide vane is guided in a flow guide way; 2.1 guide vane head; 2.2 guide vane tail; 3. An impeller front cover plate; 4. an impeller blade; 4.1 blade head; 4.2 the tail of the blade;

5. an impeller rear cover plate;6. flushing hole (groove)；7. Water guide pipe(ii) a 8. A blade working face; 9. the back of the blade; 10. a pump intake; 11. the wall surface of the pressure expansion chamber; 12. a front pump cover and a lining plate thereof; 13. a high pressure flush inlet pipe.

Detailed Description

The technical solutions provided in the present application will be further described with reference to the following specific embodiments and accompanying drawings. The advantages and features of the present application will become more apparent in conjunction with the following description.

It should be noted that the embodiments of the present application have a better implementation and are not intended to limit the present application in any way. The technical features or combinations of technical features described in the embodiments of the present application should not be considered as being isolated, and they may be combined with each other to achieve a better technical effect. The scope of the preferred embodiments of this application may also include additional implementations, and this should be understood by those skilled in the art to which the embodiments of this application pertain.

Techniques, methods, and apparatus known to those of ordinary skill in the relevant art may not be discussed in detail but are intended to be part of the specification where appropriate. In all examples shown and discussed herein, any particular value should be construed as merely illustrative, and not limiting. Thus, other examples of the exemplary embodiments may have different values.

The drawings in the present application are in simplified form and are not to scale, but rather are provided for convenience and clarity in describing the embodiments of the present application and are not intended to limit the scope of the application. Any modification of the structure, change of the ratio or adjustment of the size of the structure should fall within the scope of the technical disclosure of the present application without affecting the effect and the purpose of the present application. And the same reference numbers appearing in the various drawings of the present application designate the same features or components, which may be employed in different embodiments.

The anti-wear process strategies and technical means are detailed below by way of examples.

Example 1

The inlet wear-resistant ring 1 of the impeller is provided with a guide vane 4, and the working field of the impeller assembly after the inlet wear-resistant ring is provided with the guide vane is shown in fig. 4:

the method represented by the scheme has the following strategies: the flow direction of fluid is changed at the inlet of the pump, vortex is prevented from being generated, mud mortar is cut in advance, direct impact with the head of the blade is avoided, the head of the blade (particularly the upper half part of the blade with larger radius) is prevented from bearing direct impact of the mud mortar, and therefore the guide vane is designed on the inner wall of the inlet wear-resistant ring of the impeller to protect the head of the blade. The term "larger radius" in the art means: in the impeller blade, in order to distinguish different regions and parts of the same blade, the relative position relationship is described or different positions are distinguished according to the radius of the off-axis center of the part of the blade. This description is clear and normative.

Different from the static guide vane in the diffusion section (or the diffusion and guide section of a multi-stage centrifugal pump) which is traditionally installed behind the impeller, the guide vane 2 shown in figure 2 of the present application is installed on the inlet wear-resistant ring 1 of the impeller, a plurality of guide vanes 2 are uniformly distributed on the inner wall of the inlet wear-resistant ring 1 in the circumferential direction, and the guide vane 2 and the inlet wear-resistant ring 1 synchronously rotate along with the impeller; in addition, in the impeller, the number of the guide vanes 2 is consistent with that of the blades 4, the arrangement positions of the guide vanes are opposite to the blades 4, and gaps are reserved between the guide vanes and the blades.

So, the drainage stator 2 of this application no longer is traditional "quiet stator", but "moves the stator", drainage stator 2 and import abrasionproof ring 1 along with the impeller synchronous revolution, and drainage stator 2 can change the flow direction of fluid under the non-rated operating mode at the import of impeller, not only prevents the vortex and produces, can change the fluid trend again in order to avoid the direct impact blade head, and the problem of resisting wearing of blade head is solved fundamentally to this embodiment scheme embodiment.

The utility model provides a drainage stator that sets up is located the blade before in the flow direction, and this technological means not only avoids the blade head to bear the dead ahead directly towards under rated operating mode, avoids the blade head to bear the side the place ahead directly towards under non-rated operating mode moreover, therefore this embodiment scheme embodies its fundamentally again and solves the anti-wear problem of blade head.

In the form of the matching design, the present embodiment makes further innovation, and is shown in fig. 2 and fig. 3: a guide vane 2: from the head part 2.1 to the tail part 2.2, the blade height (h) and the blade thickness (w) are gradually increased, the flow dividing and guiding effects are enhanced, and the flow resistance effect is not generated (can be controlled to be small and can be almost ignored), so that backflow and vortex generated by collision are avoided. Because the generation of the flow choking phenomenon is controlled, the generation of the vortex phenomenon is fundamentally stopped. How to control the 'no-resistance flow effect' to be extremely small further relates to the technical scheme of the mutual relation model of the leaf height (h), the leaf thickness (w) and the application scenes (spacing, position relation, size relation and the like) of the head 2.1, and the invention task is disclosed by other patent applications.

The impeller that this application technical scheme was suitable for: the pump rotation shaft is present outside the impeller (shown in fig. 1, 2, and 3) and not inside the impeller.

Each guide vane 2 of this application impeller installs and is fixed in the inner wall position department of import abrasionproof ring 1, and the off-axis is far away, can not influence the pump throughput.

The impeller blades 4 and the guide vanes 2 in the impeller are corresponding in number and position, the guide vanes 2 are in an axial and radial inward development shape, the tail parts (2.2) of the guide vanes are close to and just face the head parts (4.1) of the impeller blades (namely the necessary technical characteristics of the application), and the guide vanes mainly play roles in flow guiding, flow guiding and flow dividing and have weak working capacity.

The traditional guide vane in the field is arranged behind the impeller and mainly plays the roles of beam flow diffusion and radial force elimination. Those skilled in the art, generally in order to ensure throughput, often avoid the use of conventional vanes in the design of dredge pumps.

Therefore, the application is an innovation of the new functional application of the traditional guide vane.

Example 2

The slurry flow in the mud pump cannot be kept stable, the instability is also often occurred near the impeller inlet, the guide vane 2 installed on the inlet wear-resisting ring 1 in the embodiment 1 is divided into two bodies with the blade 4, so that a gap (at the front region B of the blade shown in figure 6) is necessarily existed, and the unstable flow in the pump can generate vortex at the gap.

Therefore, in the embodiment 2, based on the "guide vane" scenario disclosed in the embodiment 1, it is further disclosed that a high-pressure flushing technical means is additionally adopted on the centrifugal dredge pump, and a "high-pressure flushing of the blade head" design is combined to enhance the application effect.

The obtained effect is as follows: the high-pressure flushing structure is positioned at the blade head (4.1), the jet flow direction of the high-pressure flushing structure is in a reverse flow mode, and the purpose of the measure is to form a reverse pressure gradient, so that the mud and mortar are deviated in advance, and the blade head (4.1) is prevented from being abraded by impact. In the method strategy, as the guide vane (2) is arranged on the inlet wear-resistant ring (1), and the head part (2.1) of the guide vane is positioned in the inlet flow-facing direction of the impeller, the efficiency is similar to that of the part with larger radius on the blade head (4.1) and continuously extends to the inlet of the impeller, and each guide vane (2) is physically separated from the corresponding blade (4). On one hand, the abrasion problem of the blade head (4.1) and the end face near the blade head (4.1) is directly and effectively solved, and the all-round protection of the weak point of the impeller blade is realized, so that the durability of the mud pump is ensured. On the other hand, a guide vane (2) is additionally arranged at the inlet of the impeller, and a matched high-pressure flushing structure is arranged at the head (4.1) of the blade, so that the running stability of the slurry can be further stabilized by the combined scheme, and the continuous abrasion of the slurry to the impeller is also improved.

The high-pressure flushing design of the application is different from other wall surface jet devices in principle, and belongs to novel application of a structure in a mud pump based on a new principle.

The design of 'high-pressure flushing of blade head' is structurally realized as follows:

the arrangement and position of the high pressure flush structure shown in fig. 5 is schematically illustrated:

high-pressure water sources and high-pressure sealing water between an impeller front cover plate (3) and a front pump cover and a lining plate (12) of the front pump cover are connected in the blades through a high-pressure flushing inlet pipe (13), flushing holes/grooves (6) are formed in the head parts (4.1) of the blades, high-pressure flushing water flows out from the head parts (4.1) of the blades through the flushing holes/grooves (6), a backpressure gradient is formed in a gap area (B in figures 4 and 6) between the blades and guide vanes and flows out along the tail parts (2.2) of the guide vanes, and the continuous water quality barrier weakens impact abrasion of vortex at the gap parts to the head parts (4.1) of the blades on one hand and prevents vortex from forming at the gap parts on the other hand. The existence of the guide vane (2) and high-pressure flushing form continuous shielding in the incident flow direction of the blade together, and the head of the blade, especially the position with the larger upper half diameter of the head of the blade, is protected.

The nozzle is formed by arranging flushing holes (grooves) on the head of the blade.

The "upstream direction" is the "counter-flow direction".

The blade head high-pressure flushing water in the embodiment 2 is used alone, so that enough backpressure gradient is not generated at a small flushing flow rate to divide inflow mud slurry, the flushing flow rate is too large, inflow is blocked at certain inlet flow transient, the suction performance of a mud pump is damaged, and eddy caused under abnormal conditions even can cause the abrasion of the blade head to be aggravated. In embodiment 2, the cooperation of the high pressure flushing of the blade head and the guide vane (2) further stably achieves the aim of reducing the abrasion.

The above two structures are used in combination to interact positively, as exemplified by:

1. if there is not drainage stator (2), high pressure is washed by water and can be formed the water protective screen when meeting to the silt particle forward or near forward, prevents the wearing and tearing of blade head (4.1), but the dredge pump obviously deviates from common operating mode operation, and the flowing direction of silt particle and high pressure bath may be obvious contained angle, and then produces strong vortex in leading to the blade preceding region (B department), influences the antifriction effect. The guide vane (2) not only shunts the imported mud slurry, but also optimizes the additional function of flowing under the non-rated working condition, namely under the pump operating conditions of mud slurry with different concentrations and granularities and different flow and rotating speed, the guide vane (2) guides the mud slurry flow direction impacting the blade head (4.1) into positive incident flow by doing a small amount of work, thereby avoiding generating strong vortex in the front area (B) of the blade between the guide vane tail (2.2) and the blade head (4.1), ensuring the suction performance of the impeller by the additional function, and improving the effect of flushing the blade head;

2. the drainage guide vane (2) also has the function of ensuring the flushing action range: the guide vane structure can prevent silt from directly impacting the vane, thereby reducing the pressure difference in the gap (area B) between the vane and the guide vane and enabling high-pressure flushing water to more easily impact the tail part (2.2) of the guide vane; and the diversion effect of the guide vane tail part (2.2) on flushing water also prevents the overlarge action range of flushing water. Therefore, the combination of the two structures increases the adaptability of the high-pressure flushing water quantity, and even if the high-pressure water of the blade head (4.1) is changed in a wider flow range, the water barrier can still be ensured to be filled and restrained in the gap (B area) between the guide vane tail (2.2) and the blade head (4.1). For unstable inflow mud and mortar, no matter the flushing flow is relatively small or large, the function of preventing the mud and mortar from generating vortex in the gap is exerted, and the improvement of the abrasion of the blade head is ensured.

Claims

1. An anti-wear method applied to a centrifugal mud pump is characterized in that:

2. A method according to claim 1, characterized in that the number of guide vanes 2 corresponds to the number of blades 4 in the impeller, which are arranged opposite the blades 4 with a gap between them.

3. The method according to claim 1, characterized in that the guide vane 2 is close to and facing the impeller blade 4 head.

4. The method as claimed in claim 1, characterized in that a high-pressure water source and high-pressure sealing water between the front cover plate (3) of the impeller and the front pump cover and the lining plate (12) thereof are connected in the blade through a high-pressure flushing water inlet pipe (13), flushing holes/grooves (6) are formed in the surface of the blade head (4.1), high-pressure flushing water flows through the flushing holes/grooves (6) and is ejected from the surface of the blade head (4.1), a counter pressure gradient is formed in a gap area between the blade and the guide vane, and the high-pressure flushing water is ejected along the tail (2.2) of the guide vane.