A method for pre-adjusting total tip clearance of centrifugal compressor impeller

Abstract

The application discloses a kind of centrifugal compressor impeller total play clearance pre-adjustment method, this pre-adjustment method can carry out total play clearance prediction when not installing big cover, only need to utilize the pressing device made of casing connecting bolt hole, instead of big cover and carry out pressing, and the gasket made for stress uniformity, total play clearance prediction can be completed, and if total play clearance does not meet requirements after big cover is reloaded, it is effectively avoided.The application overcomes the problem that the workload is obviously increased due to the disassembly of the big cover, improves the work efficiency, reduces the labor intensity, shortens the maintenance period, and ensures the maintenance quality.

Description

Technical Field

[0001] This invention relates to a method for pre-adjusting the total clearance of the impeller in a centrifugal compressor. Background Technology

[0002] Ingersoll Rand centrifugal compressors are widely used in the compressor industry. Our company currently has five Ingersoll Rand centrifugal compressors, supplying compressed air to Baogang Group. Because these units operate for extended periods each year, they typically require two scheduled maintenance periods annually. Maintenance includes inspecting or replacing the rotor, bearings, gas seals, and oil seals. After inspecting or replacing these components, reassembly requires measuring and adjusting the total impeller clearance. If the clearance cannot be adjusted or is outside the specified range, the unit will not operate safely. Our current method for measuring the total impeller clearance is as follows: Install the four-stage diffuser into the compressor, then install the cover, tighten the cover connecting bolts, and press the diffuser down with the cover. At this point, loosen the screws and set screws on the rear bearing, push the bearing to the gear dead center, and then push the rotor towards the diffuser dead center. Set up the dial indicator to zero and set it to the thrust plate. Pull the rotor back to the dead center on the motor side. Repeat this pushing and pulling several times to measure the total impeller movement within the diffuser. This method is useful because the gap between the diffuser and the cylinder wall is generally around 0.2mm. Even a slight misalignment of the diffuser during installation can lead to improper installation, which is not visible to the naked eye. After installing the cover and tightening the diffuser, measure the gap. If the total movement is found to be outside the specified range, the cover needs to be removed again, the diffuser position adjusted, the cover reinstalled, and the total movement gap measured again. Repeat this process until the total gap meets the requirements. The disadvantage of this method is that it requires a high level of experience and skill in diffuser installation. The total gap can only be measured after the cover is installed. If the total gap does not meet the requirements, the cover must be removed and the diffuser adjusted. This is because this type of compressor has four compression units. Figure 1 As shown, there is only one main cover. When measuring the total impeller clearance, if any of the four compression units malfunctions, the main cover must be removed to adjust the diffuser of that unit. Therefore, the entire operation is prone to repeated disassembly and reassembly of the main cover. The main cover is connected by 80 M40 bolts and weighs nearly 5 tons; each disassembly and reassembly is extremely time-consuming and labor-intensive. Given these factors, researching a way to quickly and efficiently measure the total impeller clearance of Ingersoll Rand CM series centrifugal compressors has become a pressing priority. Summary of the Invention

[0003] To address the aforementioned technical problems, the purpose of this invention is to provide a method for pre-adjusting the total axial movement clearance of a centrifugal compressor impeller.

[0004] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0005] This invention discloses a method for pre-adjusting the total axial clearance of a centrifugal compressor impeller. It eliminates the need for a main cover; instead, it utilizes bolt holes on the compressor casing to connect a clamping device, replacing the main cover for clamping, and includes washers for even force distribution. The specific operation includes the following steps:

[0006] S1. Reinstall the diffusers of each compression unit into the compressor according to the normal procedure, and at the same time, make a preliminary confirmation that the diffuser installation is in place;

[0007] S2. After installation, install the washer onto the diffuser bell, and install the clamping device onto the outside of the washer through the housing connecting bolts and the connecting holes on the channel steel. By adjusting the tightness of the bolts, control the force of the clamping device on the diffuser. When the force is appropriate, you can start measuring the total axial clearance of the impeller.

[0008] S3. When the measured total axial clearance does not meet the requirements, loosen the clamping device, remove the washer, adjust the position of the diffuser, and after adjustment, continue to install the washer on the horn. Adjust the bolt of the clamping device to the appropriate position and continue to test the total axial clearance until the clearance meets the requirements. Then, remove the clamping device and washer, and reinstall the cover. At this time, it can be ensured that the clearance is still within the specified range after the cover is reinstalled. Then the pre-adjustment of the impeller's total axial clearance is completed.

[0009] Furthermore, the clamping device is made of four 100 channel steels arranged in pairs and cross-welded, with a length of 1600MM. According to the distance of the diagonal bolt holes on the unit, φ50 connecting bolt holes are opened at appropriate positions on the four legs.

[0010] Furthermore, the washer is a circular iron ring with the same diameter as the diffuser flare and a thickness of 20 mm.

[0011] Compared with the prior art, the beneficial technical effects of the present invention are as follows:

[0012] This invention provides a method for pre-adjusting the total clearance of a centrifugal compressor impeller. This method allows for clearance pre-adjustment even before the cover is installed, effectively preventing the clearance from failing to meet requirements after the cover is reinstalled. It overcomes the problem of significantly increased workload caused by disassembling the cover, improves work efficiency, reduces labor intensity, shortens maintenance time, and ensures maintenance quality. It has significant potential for widespread application. Attached Figure Description

[0013] The present invention will be further described below with reference to the accompanying drawings.

[0014] Figure 1 A schematic diagram showing the pre-adjustment of the total axial clearance of a centrifugal compressor impeller;

[0015] Explanation of reference numerals in the attached drawings: 1. Clamping device; 2. Washer; 3. Diffuser bell; 4. Rotor. Detailed Implementation

[0016] like Figure 1 The diagram shown is a schematic of the pre-adjustment of the total axial movement clearance of the centrifugal compressor impeller. The diffuser bell 3 of each stage of the compression unit is reinstalled into the compressor according to the normal procedure. Based on experience and feel, the diffuser installation is initially confirmed to be in place. The gasket 2 is installed between the clamping device 1 and the diffuser bell 3. The clamping device 1 is connected to the casing by connecting bolts.

[0017] In this embodiment, the diffuser bell 3 and the rotor 4 are both main components of the equipment, present in all four compression stages, and their structural and positional relationships are as follows: Figure 1 They are exactly the same as shown, only the size is different, and they gradually decrease from level 1 to level 4.

[0018] In this embodiment, the diameter of the washer 2 is the same as the diameter of the diffuser flare 3. Because the diameters of the diffuser flare 3 of the first to fourth compression stages are different, four washers of different diameters are required.

[0019] In this embodiment, the clamping device is composed of four 100mm channel steel bars arranged in pairs and cross-welded, with a length of 1600mm. φ50 connecting bolt holes are drilled at appropriate positions on the four support legs according to the distance between the diagonal bolt holes on the unit. Because the four compression units have the same external dimensions, the clamping device can be used on all four compression units. Regarding the fitting method between the clamping device and the housing, this invention does not limit this; those skilled in the art can choose any connection method according to actual needs. It should be noted that regardless of the connection method chosen, it must ensure that clamping force is provided.

[0020] The specific operating method is as follows:

[0021] S1. Reinstall the diffuser bell 3 and rotor 4 of the four compression units into the compressor according to the normal procedure. Based on experience and feel, first make a preliminary confirmation that the diffuser bell is installed in place.

[0022] S2. After the installation is in place, install the washer 2 corresponding to the stage to be measured onto the diffuser bell tube 3. Install the cross-shaped clamping device 1 made of channel steel onto the outside of the washer through the housing connecting bolts and the connecting holes on the channel steel. By adjusting the tightness of the bolts, control the force applied to the diffuser bell tube 3 by the clamping device 1. When the clamping force is appropriate, the total axial clearance of the impeller of that stage can be measured.

[0023] S3. If the measured total runout clearance does not meet the requirements, it indicates that the diffuser is not installed correctly. Loosen the clamping device 1, remove the washer 2, tap the diffuser with a copper rod, and readjust the installation position of the diffuser. After adjustment, reinstall the washer 2 on the horn. Adjust the connecting bolts of the clamping device 1 and the housing to a suitable position, and continue to test the total runout clearance until the clearance meets the requirements. Then, remove the clamping device 1 and washer 2. At this point, it can be ensured that after the cover is reinstalled, the impeller's total runout clearance is still within the specified range, and the impeller's total runout clearance pre-adjustment is complete. The cover can then be reinstalled.

[0024] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for pre-adjusting the total axial movement clearance of a centrifugal compressor impeller, characterized in that: No large cover is needed; simply connect the clamping device using the bolt holes on the housing to perform clamping instead of the large cover, along with washers for even force distribution, to complete the pre-adjustment of the overall lateral clearance. The specific operation includes the following steps: S1. Reinstall the diffusers of each compression unit into the compressor according to the normal procedure, and at the same time, make a preliminary confirmation that the diffuser installation is in place; S2. After installation, install the washer onto the diffuser bell. Connect the bolt holes of the clamping device to the bolt holes on the housing to install the clamping device outside the washer. Adjust the tightness of the bolts to control the force of the clamping device on the diffuser. When the force is appropriate, you can start measuring the total axial clearance of the impeller. S3. When the measured total axial clearance does not meet the requirements, loosen the clamping device, remove the washer, adjust the position of the diffuser, and after adjustment, continue to install the washer on the horn. Adjust the bolt of the clamping device to the appropriate position and continue to test the total axial clearance until the clearance meets the requirements. Then, remove the clamping device and washer, and reinstall the cover. At this time, it can be ensured that the clearance is still within the specified range after the cover is reinstalled. Then the pre-adjustment of the impeller's total axial clearance is completed.

2. The method for pre-adjusting the total axial movement clearance of a centrifugal compressor impeller according to claim 1, characterized in that: The clamping device is made of four 100 channel steels arranged in pairs and welded in a cross shape, with a length of 1600MM. φ50 bolt holes are drilled at appropriate positions on the four legs according to the distance between the diagonal bolt holes on the housing.

3. The method for pre-adjusting the total axial clearance of a centrifugal compressor impeller according to claim 1, characterized in that: The washer is a circular iron ring with the same diameter as the diffuser flare and a thickness of 20 mm.

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