Repair method for severe abrasion of impeller wear ring of single-suction centrifugal pump

Abstract

The invention discloses a repair method for severe wear of a wear ring of an impeller of a single-suction centrifugal pump, which comprises the following repair steps of: S1, dismounting the worn impeller from a pump body, and flattening the worn wear ring of the impeller by using a lathe; s2, the outer diameter size of the impeller wear ring and the inner diameter size of the volute wear ring after finishing are measured, and a gap between the impeller wear ring and the volute wear ring at the present stage is obtained; s3, selecting a steel pipe with a proper size according to the size of the gap at the current stage, measuring the width of the position of the impeller wear ring, machining the inner part and the outer part of the steel pipe by using a lathe, and ensuring that the machined inner part of the steel pipe can be arranged in the flattened position of the impeller wear ring; and S4, the machined steel pipe is heated and inlaid in the position of the impeller wear ring, interference fit is kept, and the grown steel pipe is cut off through a lathe after cooling. The abraded impeller wear ring can be repaired to the original state according to the requirement for the gap between the impeller wear ring and the pump body volute wear ring of the single-suction centrifugal water pump and the material requirement, and the original efficiency of the water pump is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of repairing damaged centrifugal pump impellers, and particularly relates to a method for repairing severe wear of the impeller mouth ring of a single-suction centrifugal pump. Background Art

[0002] During the daily production process of a centrifugal pump, the impeller mouth ring and the volute mouth ring of the pump casing play a role of mutual sealing. Therefore, after the gap becomes too large, some of the medium at the outlet side of the impeller will flow back to the inlet, resulting in a decrease in the flow rate and head of the pump. If the gap is too small, it will cause mutual friction between the impeller mouth ring and the volute mouth ring of the pump casing, affecting the normal operation of the water pump. During the long-term production process, when an ordinary single-suction water pump is in operation, due to the wear of the bearings, the rotor is not on the same horizontal line. In this case, affected by gravity, the entire rotor will sag, which will cause mutual friction between the impeller mouth ring and the lower volute mouth ring of the pump casing, resulting in an increase in the gap between the impeller mouth ring and the volute mouth ring. Even if the bearings are replaced and the centrifugal pump can operate normally, it cannot reach the original efficiency. Once the impeller mouth ring is severely worn, generally a new impeller is replaced and the old impeller is scrapped, but this will cause a large amount of maintenance costs and the cost is too high. At the same time, during the long-term production process, it is inevitable that in the early stage of the fault, the inspection is not in place, resulting in serious equipment accidents. Summary of the Invention

[0003] In order to solve certain or some technical problems existing in the prior art, the purpose of the present application is to provide a method for repairing severe wear of the impeller mouth ring of a single-suction centrifugal pump, which can repair the worn impeller mouth ring to the original state according to the requirements of the gap and material between the impeller mouth ring of the single-suction centrifugal pump and the volute mouth ring of the pump body, and achieve the original efficiency of the water pump.

[0004] To solve the above-mentioned existing technical problems, the present application is implemented by adopting the following technical solutions:

[0005] A method for repairing severe wear of the impeller mouth ring of a single-suction centrifugal pump, the repair steps include:

[0006] S1. Remove the worn impeller from the pump body and use a lathe to level the worn mouth ring of the impeller;

[0007] S2. Measure the outer diameter dimension of the repaired impeller mouth ring and the inner diameter dimension of the volute mouth ring to obtain the current gap between the impeller mouth ring and the volute mouth ring;

[0008] S3. According to the size of the current gap, select a steel pipe with a suitable size, measure the width of the impeller mouth ring position, and process the inner and outer parts of the steel pipe with a lathe to ensure that the inner part of the processed steel pipe can be installed into the processed and leveled impeller mouth ring part;

[0009] S4. Heat the processed steel pipe and insert it into the impeller mouth ring position, maintaining an interference fit. After cooling, use a lathe to cut off the protruding steel pipe.

[0010] Preferably, after processing in the lathe in step S3, the inserted steel pipe is polished to achieve a suitable clearance.

[0011] Preferably, the surface roughness of the outer surface of the impeller mouth ring after the leveling treatment in step S1 is Ra0.2 to Ra1.6.

[0012] Preferably, the inner diameter of the original steel pipe in step S3 is 1 - 3 mm smaller than the outer diameter of the impeller mouth ring, and the wall thickness of the steel pipe is 1 - 5 mm greater than the current clearance; before processing the inner and outer parts of the steel pipe with a lathe, remove the oil and impurities on the surface of the steel pipe to ensure its surface finish.

[0013] Preferably, the inner diameter of the steel pipe after processing in step S3 is 0.1 - 0.3 mm smaller than the outer diameter of the impeller mouth ring.

[0014] Preferably, the steel pipe inserted in the impeller mouth ring position in step S4 is welded by argon arc welding.

[0015] Preferably, the welding points of the argon arc welding are at the 3 o'clock, 6 o'clock, 9 o'clock, and 12 o'clock positions of the impeller mouth ring, and spot welding is used for fixation.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0017] According to the requirements of the clearance and material between the impeller mouth ring and the pump casing mouth ring, appropriately select a matching steel pipe for interference fit heating and insertion, and cooperate with welding and polishing treatment at the top edge to achieve firm installation and a suitable clearance. The worn impeller mouth ring can be repaired to its original state, achieving the original efficiency of the water pump. Through continuous operation observation and testing after repairing the single-suction centrifugal pump impeller, no abnormal operation conditions or phenomena not meeting the process conditions are found. The clearance between the impeller mouth ring and the volute mouth ring has been completely solved, avoiding the problem of high cost in replacing a new impeller. While reducing the maintenance cost, it effectively reduces or even avoids the risk of serious equipment accidents caused by inadequate pre-fault inspection. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the repair of the impeller mouth ring of the present invention. In the figure, 1 - normal mouth ring, 2 - worn mouth ring, 3 - mouth ring leveling treatment, 4 - heating and inserting a suitable steel pipe on the mouth ring, 5 - repaired mouth ring. DETAILED DESCRIPTION OF THE INVENTION

[0019] Next, in combination with the accompanying drawings and specific embodiments, the present application will be further described. It should be noted that, on the premise of no conflict, the following-described embodiments or technical features can be arbitrarily combined with each other to form new embodiments.

[0020] In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "left", "right", etc. is based on the orientation or positional relationship shown in the accompanying drawings. It is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present application.

[0021] The terms "first", "second", etc. in the present application are used to distinguish similar objects, rather than to describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances, so that the embodiments of the present application can be implemented in an order other than those illustrated or described herein, and the objects distinguished by "first", "second", etc. are generally of the same type, and the number of objects is not limited. For example, the first object can be one or multiple. In addition, "and / or" in the specification and claims means at least one of the connected objects, and the character " / " generally indicates an "or" relationship between the associated objects before and after.

[0022] A repair method for serious wear of the impeller mouth ring of a single-suction centrifugal pump, the repair steps including:

[0023] S1. Remove the worn impeller from the pump body, and use a lathe to level the worn mouth ring of the impeller; the surface roughness of the outer surface of the impeller mouth ring after leveling is Ra0.2 to Ra1.6;

[0024] S2. Measure the outer diameter size of the trimmed impeller mouth ring and the inner diameter size of the volute mouth ring to obtain the current gap between the impeller mouth ring and the volute mouth ring;

[0025] S3. According to the size of the current gap, select a steel pipe with a suitable size, measure the width at the position of the impeller mouth ring, and process the inner and outer parts of the steel pipe with a lathe to ensure that the inner part of the processed steel pipe can be installed into the processed impeller mouth ring part; the inner diameter of the original steel pipe is 1 to 3 mm smaller than the outer diameter size of the impeller mouth ring, and the wall thickness of the steel pipe is 1 to 5 mm greater than the current gap; before processing the inner and outer parts of the steel pipe with a lathe, remove the oil stains and impurities on the surface of the steel pipe to ensure its surface finish; the inner diameter of the processed steel pipe is 0.1 to 0.3 mm smaller than the outer diameter size of the impeller mouth ring;

[0026] S4. Heat the processed steel pipe and inlay it into the position of the impeller mouth ring to maintain an interference fit, and use a lathe to cut off the protruding steel pipe after cooling.

[0027] During the process of repairing the worn impeller mouth ring of a single-suction centrifugal pump, use appropriate tools to safely remove the worn impeller from the pump body. Subsequently, install the removed impeller on a lathe and select a suitable cutting tool for precise cutting. During the cutting process, it is necessary to closely monitor the cutting depth and feed rate to ensure that the surface roughness after cutting can meet the established standard. After the cutting operation, use a surface roughness detection instrument to carefully detect the cutting surface to ensure that the surface roughness falls within the range of Ra0.2 to Ra1.6 to meet the precise requirements of subsequent measurements. High-precision measuring tools such as vernier calipers or micrometers should be used during measurement to ensure the accuracy of the measurement results. Record in detail the outer diameter size of the impeller mouth ring and the inner diameter size of the volute mouth ring measured, and calculate the clearance value between them. This clearance value will be used as an important reference basis in subsequent repair steps to ensure that the fitting accuracy between the repaired impeller mouth ring and the volute mouth ring meets the requirements, thereby restoring the original efficiency of the water pump. Then, according to the current size of the clearance, select a steel pipe of appropriate size, measure the width of the impeller mouth ring position, and process the inner and outer parts of the steel pipe on a lathe to ensure that the inner part of the processed steel pipe can be installed into the processed impeller mouth ring part; when selecting a steel pipe of the same material as the impeller according to the current clearance size, the inner diameter of the steel pipe should be about 1 mm to 3 mm smaller than the outer diameter size of the impeller mouth ring, and the wall thickness of the steel pipe is greater than the current clearance by about 1 mm to 5 mm, and precisely measure the width of the impeller mouth ring position. Use a lathe to finely process the inner and outer surfaces of the steel pipe. Remove the oil stains and impurities on the surface of the steel pipe before processing to ensure its surface finish. The inner diameter of the processed steel pipe should be about 0.1 mm to 0.3 mm smaller than the outer diameter size of the impeller mouth ring to ensure that the inner diameter of the processed steel pipe exactly matches the size of the impeller mouth ring after leveling; finally, heat the processed steel pipe and inlay it into the impeller mouth ring position, maintaining an interference fit. After cooling, use a lathe to cut off the protruding steel pipe; apply heat treatment to the processed steel pipe to induce the thermal expansion effect of the steel pipe; then use heat treatment and freezing treatment methods to precisely embed the processed steel pipe into the designated position of the impeller mouth ring to ensure an appropriate interference fit between the two to ensure the stability and durability of mechanical components. Compared with using freezing technology, such as using liquid nitrogen to freeze the impeller mouth ring, the cost is relatively lower. Appropriately select a matching steel pipe for interference fit heating and inlay according to the requirements of the clearance and material between the impeller mouth ring and the pump shell mouth ring, and use welding and polishing treatments in combination with the top edge to achieve firm installation and a suitable clearance. The worn impeller mouth ring can be repaired to its original state, achieving the original efficiency of the water pump.Through continuous operation observation and test after the repair of the single-suction centrifugal pump impeller, no abnormal operation conditions or phenomena that do not meet the process conditions were found. The gap between the impeller mouth ring and the volute mouth ring has been completely solved, avoiding the problem of high cost in replacing a new impeller. While reducing the maintenance cost, it effectively reduces or even avoids the risk of serious equipment accidents caused by insufficient inspection in the early stage of the failure.

[0028] Further improvement is that after machining in the step S3 by a lathe, the inlaid steel pipe is polished to achieve a suitable gap.

[0029] By polishing to achieve a suitable gap, whether the steel pipe is assembled with the impeller mouth ring or installed on the volute mouth ring, it can make its contact surface smoother and have higher precision control, and it is not easy to have the situation of exceeding the specified gap range.

[0030] Further improvement is that the steel pipe inlaid at the impeller mouth ring position in the step S4 is welded by argon arc welding; the welding points of the argon arc welding are at the 3 o'clock, 6 o'clock, 9 o'clock, and 12 o'clock positions of the impeller mouth ring, and spot welding is used for fixation.

[0031] Since the impeller mouth ring and the steel pipe are fixed by heating and inlaying, in order to avoid the phenomenon of relative sliding in the later stage, the steel pipe inlaid at the impeller mouth ring position is welded again by argon arc welding, which can effectively improve the firmness and strengthen the strength after hot inlaying. And in order to ensure sufficient firmness after welding without affecting its appearance and working strength, the welding points of the argon arc welding are at the 3 o'clock, 6 o'clock, 9 o'clock, and 12 o'clock positions of the impeller mouth ring, which can ensure uniform welding points between the two and reduce the number of welding points. At the same time, although the firmness is higher after full welding, there will inevitably be a situation where the impeller mouth ring position needs to be repaired due to secondary wear. Therefore, the combination of heating and inlaying and 4-point spot welding can also facilitate the disassembly of the worn steel pipe. When performing secondary repair, it is no longer necessary to perform a large amount of treatment on the original impeller mouth ring, and it can be directly used for assembly or simply polished and then repaired. The secondary repair is more convenient and the cost is lower.

[0032] The above embodiments are only the preferred embodiments of the present application and cannot be used to limit the scope of protection of the present application. Any non-substantial changes and substitutions made by those skilled in the art based on the present application belong to the scope of protection required by the present application.

Claims

1. A method for repairing a severely worn impeller ring of a single-suction centrifugal pump, characterized in that: The repair steps include: S1. Remove the worn impeller from the pump body and use a lathe to smooth the worn ring of the impeller. S2. Measure the outer diameter of the impeller ring and the inner diameter of the volute ring after trimming to obtain the current gap between the impeller ring and the volute ring; S3. According to the size of the gap at the current stage, select a steel pipe of appropriate size, measure the width of the impeller mouth ring position, and use a lathe to process the inner and outer parts of the steel pipe to ensure that the processed steel pipe internal parts can be installed in the impeller mouth ring position after flattening; S4. Heat the processed steel pipe and insert it into the impeller ring position, maintain interference fit, and use a lathe to cut off the excess steel pipe after cooling.

2. The method for repairing a severely worn impeller ring of a single-suction centrifugal pump according to claim 1, characterized in that: The outer surface roughness of the impeller ring after the flattening treatment in step S1 is Ra0.2 to Ra1.

6.

3. The method for repairing a severely worn impeller ring of a single-suction centrifugal pump according to claim 1, characterized in that: After the lathe processing in step S3, the embedded steel pipes are polished to achieve a suitable gap.

4. The method for repairing a severely worn impeller ring of a single-suction centrifugal pump according to claim 3, characterized in that: The inner diameter of the original steel pipe in step S3 is 1-3 mm smaller than the outer diameter of the impeller ring, and the wall thickness of the steel pipe is 1-5 mm greater than the current gap; before machining the inner and outer parts of the steel pipe with a lathe, oil stains and impurities on the surface of the steel pipe are removed to ensure its surface smoothness.

5. The method for repairing a severely worn impeller ring of a single-suction centrifugal pump according to claim 4, characterized in that: The inner diameter of the steel pipe after processing in step S3 is 0.1 to 0.3 mm smaller than the outer diameter of the impeller ring.

6. The method for repairing a severely worn impeller ring of a single-suction centrifugal pump according to claim 1, characterized in that: In the step S4, the steel pipe embedded in the impeller mouth ring position is welded by argon arc welding.

7. The method for repairing a severely worn impeller ring of a single-suction centrifugal pump according to claim 1, characterized in that: The welding points of the argon arc welding are at the 3 o'clock, 6 o'clock, 9 o'clock and 12 o'clock positions of the impeller mouth ring, and are fixed by spot welding.

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