Water pump impeller for large diesel engine centrifugal pump

Abstract

The utility model discloses a water pump impeller for a large diesel centrifugal pump, which comprises an impeller body and a wear-resistant and corrosion-resistant composite layer, and the composite layer at least covers the surface of a shaft sleeve of the impeller body. The composite layer comprises a wear-resistant layer and an anti-corrosion hole sealing layer, the wear-resistant layer is tightly attached to the surface of the shaft sleeve, and the hole sealing layer is tightly attached to the wear-resistant layer. According to the water pump impeller for the centrifugal pump of the large diesel engine, the composite layer is arranged on the surface of the shaft sleeve of the impeller body, so that the corrosion resistance and the wear resistance of the surface can be improved on the basis that the original structure, rigidity and strength of the shaft sleeve are kept, and the service life of the impeller shaft sleeve in the using process in high-salt and high-humidity environments is prolonged; and the service life of the whole impeller is prevented from being influenced by shaft sleeve damage.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of protective film especially relates to a water pump impeller for large diesel engine centrifugal pump. BACKGROUND

[0002] Large diesel engines are widely used in the fields of nuclear power emergency, ship propulsion and power generation. Centrifugal pumps are indispensable components of large diesel engines, and their main function is to absorb and remove a large amount of heat generated in the combustion chamber through circulating cooling medium (such as water or coolant), thereby maintaining the engine components within the appropriate operating temperature range. The impeller, as a key component of the cooling system, is responsible for pumping cooling medium from the radiator or water tank and pressurizing it for delivery to the cooling water channel of the diesel engine. The performance of the centrifugal pump impeller directly affects the flow and pressure of the cooling medium, which in turn affects the cooling effect. Leakage of the cooling medium can cause the cooling system to fail, seriously threatening the availability of the emergency diesel engine and the safety of the system.

[0003] As the use environment of centrifugal pumps continues to expand, higher requirements are placed on the wear resistance and corrosion resistance of the key component, the impeller shaft sleeve part. Since the cooling medium may contain corrosive substances or impurities, the material and sealing elements of the centrifugal pump need to have good corrosion resistance and wear resistance. Traditional impellers require nitriding treatment of the entire impeller during manufacturing to maintain material stiffness and toughness, which can cause high-temperature effects and unpredictable deformation during the nitriding process. In addition, the impeller is affected by multiple factors such as mechanics, chemistry and electrochemistry during use, with complex damage mechanisms and unclear development process. Currently, only visual inspection is used, and there is a lack of real-time monitoring and prediction means. SUMMARY

[0004] The utility model solves the technical problem of providing a water pump impeller for a large diesel engine centrifugal pump.

[0005] The utility model adopts the technical scheme that a water pump impeller for a large diesel engine centrifugal pump comprises an impeller body and a wear-resistant and corrosion-resistant composite layer, and the composite layer covers at least the surface of the shaft sleeve of the impeller body.

[0006] The composite layer comprises a wear-resistant wear-resistant layer and a corrosion-resistant hole sealing layer, the wear-resistant layer is tightly attached to the surface of the shaft sleeve, and the hole sealing layer is tightly attached to the surface of the wear-resistant layer and the shaft sleeve part of the impeller body.

[0007] In some embodiments, the wear-resistant layer comprises a plurality of Cr layers and a plurality of CrN layers interleaved and stacked.

[0008] In some embodiments, the thickness of the Cr layer is 1-4 microns.

[0009] In some embodiments, the thickness of the CrN layer is 1-4 μm.

[0010] In some embodiments, the total number of layers of the Cr layer and the CrN layer is 4-10 layers.

[0011] In some embodiments, the thickness of the wear-resistant layer is 8-35 μm.

[0012] In some embodiments, the hole sealing layer is an amorphous silicon-oxygen layer.

[0013] In some embodiments, the thickness of the hole sealing layer is 1-3 μm.

[0014] In some embodiments, the composite layer is tightly attached to the inner surface and the outer surface of the shaft sleeve.

[0015] In some embodiments, the impeller body is made of spheroidal graphite cast iron, compacted graphite cast iron, 40Cr, 45Cr, 42CrMo or stainless steel.

[0016] By implementing the present utility model, the following beneficial effects are achieved:

[0017] The water pump impeller for a large diesel engine centrifugal pump comprises an impeller body and a wear-resistant and corrosion-resistant composite layer, the composite layer is at least covered on the surface of a shaft sleeve of the impeller body, the composite layer comprises a wear-resistant wear-resistant layer and a corrosion-resistant hole sealing layer, the wear-resistant layer is tightly attached to the surface of the shaft sleeve, and the hole sealing layer is tightly attached to the surface of the wear-resistant layer and the shaft sleeve. BRIEF DESCRIPTION OF DRAWINGS

[0018] The present utility model will be further described below in combination with the drawings and embodiments, and the drawings show:

[0019] Figure 1 is a structural schematic view of the water pump impeller for a large diesel engine centrifugal pump according to an embodiment of the present utility model;

[0020] Figure 2 is Figure 1 a structural schematic view of the composite layer in the water pump impeller for a large diesel engine centrifugal pump. DETAILED DESCRIPTION

[0021] In order to have a clearer understanding of the technical features, objects and effects of the present application, the specific embodiments of the present application will be described in detail with reference to the drawings.

[0022] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0023] In the description of the present application, it should be understood that the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings based on the orientation or positional relationship shown in the drawings, and are only for the purpose of facilitating the description of the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second" and the like are only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features with "first", "second" and the like can explicitly or implicitly include one or more of the features. In the description of the present application, unless otherwise specified, the meaning of "a plurality of" is two or more.

[0024] In the description of the present application, it should be noted that unless otherwise specified and limited, the terms "mounting", "connecting", "connection" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be chemically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium, or it can be connected inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0025] Referring to Figure 1The utility model discloses a large -scale diesel engine centrifugal pump water pump impeller, including impeller body 10 and wear -resisting and anticorrosive composite layer 20, composite layer 20 at least covers the surface of the shaft sleeve 30 of impeller body 10. For example composite layer 20 covers the outer surface of the shaft sleeve 30, composite layer 20 covers the inner surface of the shaft sleeve 30 or composite layer 20 covers the outer surface of the shaft sleeve 30 and the inner surface of the shaft sleeve 30. Wherein, composite layer 20 is used to improve the wear resistance and corrosion resistance of the shaft sleeve 30, and the composite layer is formed by arc ion plating and plasma chemical vapor deposition technology, coated on the shaft sleeve 30, and closely attached to the inner surface and the outer surface of the shaft sleeve 30. The purpose of the surface of the composite layer 20 and the shaft sleeve 30 is to prevent the composite layer 20 from falling off the shaft sleeve 30, thereby improving the wear resistance and corrosion resistance of the shaft sleeve 30. It can be understood that in other embodiments, the surface of the impeller body 10 can be provided with a composite layer 20, which is not limited here, and is determined according to the actual situation.

[0026] The impeller body 10 can be spheroidal cast iron, vermicular cast iron, 40Cr, 45Cr, 42CrMo or stainless steel material. For example, in the embodiment, the impeller body 10 can be spheroidal cast iron, which has a higher degree of adhesion with the composite layer 20. In other embodiments, the material of the impeller body 10 can also be other, vermicular cast iron, 40Cr, 45Cr, 42CrMo or stainless steel material, etc., which is not limited here, and is determined according to the actual situation.

[0027] The utility model discloses a composite layer 20, thereby need not to carry out nitriding treatment to whole impeller body 10, can avoid the influence that high temperature brings to impeller body 10 in nitriding treatment process, thereby keeps the original rigidity and tenacity of the material of impeller body 10, also can avoid the influence that unpredictable deformation in nitriding treatment process brings to the form of impeller body 10.

[0028] See Figure 2 The composite layer 20 includes a wear-resistant layer 2 and a corrosion-resistant sealing layer 1. The wear-resistant layer 2 is closely attached to the surface of the shaft sleeve 30, and the corrosion-resistant sealing layer 1 is closely attached to the outer surface of the wear-resistant layer 2 away from the impeller body 10. The wear-resistant layer 2 can significantly improve the bonding force between the composite layer 20 and the shaft sleeve 30, and can be deposited on the surface of the shaft sleeve 30 by arc ion plating technology. The corrosion-resistant sealing layer 1 can prevent corrosion solution from directly contacting the base through the tiny pores in the wear-resistant layer 2 during the deposition process, thereby preventing corrosion and further improving the corrosion resistance of the composite layer 20. The corrosion-resistant sealing layer 1 can be formed on the outer surface of the wear-resistant layer 2 away from the impeller body 10 by plasma chemical vapor deposition technology. The close adhesion of the wear-resistant layer 2 and the corrosion-resistant sealing layer 1 can prevent the corrosion-resistant sealing layer 1 from falling off the wear-resistant layer 2, thereby improving the wear resistance and corrosion resistance of the shaft sleeve 30.

[0029] In some embodiments, the wear-resistant layer 2 comprises a plurality of Cr layers 21 and a plurality of CrN layers 22 stacked alternately. The Cr layer 21 refers to a coating layer composed of chromium (element symbol Cr), and the CrN layer 22 refers to a coating layer with chromium nitride (CrN for short) as the main component. The plurality of Cr layers 21 and the plurality of CrN layers 22 are arranged from the bushing 30 to the sealing layer 1, which can be in the structure of bushing 30-Cr layer 21-CrN layer 22-Cr layer 21-CrN layer 22-sealing layer 1, bushing 30-CrN layer 22-Cr layer 21-CrN layer 22-Cr layer 21-CrN layer 22-sealing layer 1, or bushing 30-Cr layer 21-CrN layer 22-Cr layer 21-CrN layer 22-Cr layer 21-sealing layer 1, etc. The Cr layer 21 and the CrN layer 22 themselves have good hardness and can also play a role in changing the composite hardness gradient from the substrate, providing the bonding force between the composite layer 20 and the bushing 30.

[0030] In some embodiments, the total number of Cr layers 21 and CrN layers 22 is 4 to 10 layers. For example, 4 layers, 5 layers, 6 layers, 7 layers, 8 layers, 9 layers, or 10 layers. When the total number is an even number, the number of Cr layers 21 is equal to the number of CrN layers 22. Preferably, when the total number is an odd number, the number of Cr layers 21 is greater than the number of CrN layers 22, that is, the CrN layer 22 is closely attached to the bushing 30.

[0031] In some embodiments, the thickness of the Cr layer 21 is 1 μm to 4 μm. For example, 1 μm, 2 μm, 2.5 μm, 3.5 μm, or 4 μm, etc. The thickness of different Cr layers 21 in the same wear-resistant layer 2 can be partially the same, all the same, or all different.

[0032] In some embodiments, the thickness of the CrN layer 22 is 1 μm to 4 μm. For example, 1 μm, 2 μm, 2.5 μm, 3.5 μm, or 4 μm, etc. The thickness of different CrN layers 22 in the same wear-resistant layer 2 can be partially the same, all the same, or all different.

[0033] In some embodiments, the overall thickness of the wear-resistant layer 2 is 8-35 μm. For example, 8 μm, 12 μm, 25 μm, 30 μm, 35 μm, etc. The overall thickness of the wear-resistant layer 2 is the sum of the overall thickness of the Cr layer 21 and the overall thickness of the CrN layer 22, and the overall thickness of the Cr layer 21 and the overall thickness of the CrN layer 22 can be the same or different, and the thickness of a single Cr layer 21 and the thickness of a single CrN layer 22 can also be the same or different. For example, the total number of Cr layers 21 is 3, the thickness of a single Cr layer 21 is 2 μm, and the overall thickness of the Cr layer 21 is 6 μm; the total number of CrN layers 22 is 4, the thickness of a single CrN layer 22 is 3 μm, and the overall thickness of the CrN layer 22 is 12 μm; then the overall thickness of the wear-resistant layer 2 is 18 μm.

[0034] In some embodiments, the sealing layer 1 is an amorphous silicon-oxygen layer. The amorphous silicon-oxygen layer has good chemical resistance and can resist the corrosion of various chemicals. The sealing layer 1 blocks the fine pore structure in the middle of the wear-resistant layer 2, prevents the corrosion solution from directly contacting the substrate through the tiny pores during the deposition process, and forms corrosion, thereby further improving the corrosion resistance of the composite layer 20.

[0035] In some embodiments, the thickness of the sealing layer 1 is 1-3 μm. For example, 1 μm, 2 μm, 2.5 μm, 3 μm, etc. The thickness of the sealing layer 1 and the thickness of the wear-resistant layer 2 are added to the total thickness of the composite layer 20, and the total thickness of the composite layer 20 is 9-38 μm, for example, 9 μm, 12 μm, 25 μm, 30 μm, 35 μm, 38 μm, etc. When the total thickness of the composite layer 20 is 15 μm, the thickness of the sealing layer 1 can be 1 μm, the thickness of the wear-resistant layer 2 is 14 μm, or the thickness of the sealing layer 1 can be 2 μm, the thickness of the wear-resistant layer 2 is 13 μm, etc. There are many setting modes, which are set according to actual needs.

[0036] The manufacturing method of the water pump impeller for the large diesel engine centrifugal pump is as follows:

[0037] Firstly, the inner and outer surfaces of the shaft sleeve 30 are polished and cleaned, the inner and outer surfaces of the impeller shaft sleeve 30 are polished by sandpaper, the oxide layer and rust are removed, and the surface is more smooth, and the oxide skin and polishing paste on the inner and outer surfaces of the impeller shaft sleeve 30 are removed in ethanol solution after polishing. The cleaned shaft sleeve 30 is loaded into the vacuum chamber of the electric arc and plasma chemical vapor deposition composite deposition system.

[0038] Then, the vacuum degree of the vacuum chamber is extracted to 10 -3 Pa or below, high-purity argon is introduced, the flow rate is 50 sccm, etching cleaning is carried out under the condition that the workpiece bias is-200 V, further pollutants and oxide layers on the surface of the workpiece are removed, and the bonding performance of the coating and the substrate is improved.

[0039] Then, the Cr target is opened, a bias voltage of -100V is applied, an arc current of 120A is applied, and a deposition time is 10 minutes; then, the bias voltage and the arc target current are kept unchanged, nitrogen gas is introduced, a gas pressure is kept at 200Pa, and a deposition time is 10 minutes. The deposition of the Cr layer 21 and the deposition of the CrN layer 22 are repeated several times respectively to form the wear-resistant layer 2 which is composed of several Cr layers 21 and several CrN layers 22.

[0040] Finally, tetramethyldisiloxane is used as a reaction gas source, a flow rate is kept at 150sccm, argon gas is introduced during the deposition process, a flow rate is kept at 200sccm, a bias voltage is -500V during the deposition process, and the amorphous silicon oxide sealing hole top layer is formed into the sealing hole layer 1 with a thickness controlled at 1-3um.

[0041] The Cr layer 21, the CrN layer 22 and the sealing hole layer 1 in the composite layer 20 are dense in structure, the wear rate of the composite layer 20 can be reduced, and the surface is free of rust and corrosion after a salt spray test for 244 hours.

[0042] By implementing the utility model, the following beneficial effects are achieved:

[0043] The water pump impeller for a large diesel engine centrifugal pump has the composite layer 20 arranged on the surface of the shaft sleeve 30 of the impeller body 10, the surface corrosion resistance and wear resistance of the shaft sleeve 30 are improved on the basis of keeping the original structure, rigidity and strength of the shaft sleeve 30, the service life of the shaft sleeve 30 in a high-salt and high-humidity environment is improved, and the use life of the entire impeller is prevented from being affected by damage to the shaft sleeve 30. The process is simple, and the operation is convenient and fast.

[0044] It can be understood that the above embodiment only expresses the preferred embodiment of the utility model, the description is more specific and detailed, but it cannot be understood as a limitation on the patent scope of the utility model; it should be pointed out that, for ordinary skilled persons in the art, the above embodiment or technical features can be freely combined without departing from the concept of the utility model, and a plurality of modifications and improvements can be made, which all belong to the protection scope of the utility model, that is, the embodiments described in "in some embodiments" can be freely combined with any of the above and below embodiments; therefore, any equivalent transformation and modification made to the patent claim scope of the utility model should belong to the coverage range of the patent claim of the utility model.

Claims

1. A water pump impeller for large diesel engine centrifugal pumps, characterized in that The impeller body (10) and the wear-resistant and corrosion-resistant composite layer (20) covering at least the surface of the shaft sleeve (30) of the impeller body (10); The composite layer (20) comprises a wear-resistant wear-resistant layer (2) and a corrosion-resistant sealing layer (1), the wear-resistant layer (2) is closely combined with the surface of the shaft sleeve (30), and the sealing layer (1) is closely combined with the wear-resistant layer (2) on the outer surface of the shaft sleeve (30).

2. The water pump impeller for large diesel engine centrifugal pumps according to claim 1, characterized in that The wear-resistant layer (2) comprises a plurality of Cr layers (21) and a plurality of CrN layers (22) interleaved and stacked.

3. The water pump impeller for large diesel engine centrifugal pumps according to claim 2, characterized in that The thickness of the Cr layer (21) is 1-4 μm.

4. The water pump impeller for large diesel engine centrifugal pumps according to claim 2, characterized in that, The thickness of the CrN layer (22) is 1-4 μm.

5. The water pump impeller for large diesel engine centrifugal pumps according to claim 2, characterized in that, The total number of the Cr layer (21) and the CrN layer (22) is 4-10 layers.

6. The water pump impeller for a large diesel engine centrifugal pump according to any one of claims 1 to 5, characterized by The thickness of the wear-resistant layer (2) is 8-35 μm.

7. The water pump impeller for large diesel engine centrifugal pumps according to any one of claims 1 to 5, characterized in that The sealing layer (1) is an amorphous silicon-oxygen layer.

8. The water pump impeller for large diesel engine centrifugal pumps according to any one of claims 1 to 5, characterized in that The thickness of the sealing layer (1) is 1-3 μm.

9. The water pump impeller for large diesel engine centrifugal pumps according to any one of claims 1 to 5, characterized in that The composite layer (20) is closely combined with the inner and outer surfaces of the shaft sleeve (30).

10. The water pump impeller for large diesel engine centrifugal pumps according to any one of claims 1 to 5, characterized in that The impeller body (10) is made of spheroidal graphite cast iron, compacted graphite cast iron, 40Cr, 45Cr, 42CrMo or stainless steel.

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