Adjustment of multi-stage pump bearing shell tension, bearing shell clearance, and shaft-bearing coaxiality
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Why didn’t anyone reply to the post that was made a few days ago? Was it because HaiChuan didn’t approve it? Posting this again today. I hope experts from all over can offer their guidance. Thank you. I need detailed explanations regarding the tightening force of multi-stage pump bearing shells, the clearance between these bearing shells, as well as the methods, steps, and principles behind adjusting the coaxiality between the bearings and the shaft. Examples would be appreciated. Thank you to all the experts out there
I’ll join in. Your question specifies many conditions; based on what you’ve said, I guess such pumps are large pumps with sliding bearings. As a large pump, it is necessary to have technical data regarding its installation and maintenance, that is, instructions on the conditions under which the equipment should be installed and maintained, with the relevant data being clearly specified. Although I haven’t provided specific figures, the method I offered should be worth considering by you. As a mature and legitimate enterprise, these items, along with the instruction manuals, must be archived. If not, it is best for the equipment procurement department to provide technical support to the manufacturer. (For reference) The specific installation data are related to the rotor’s shaft diameter, rotational speed, and other factors. Therefore, accurate data cannot be provided.
As mentioned by the user in post 2, original installation or operation manuals should generally be available. If they are indeed not available, it is recommended to refer to the SHS 01013 guidelines for the maintenance and repair of centrifugal pumps; section 3, which deals with maintenance and quality standards, describes various installation procedures such as alignment and adjustment of bearing clearances.
Thank you, you have all of that mentioned, but what I need are the specific steps for the measurement method, not the gap standards
The gaps in various areas can be measured by using a lead wire
Hello, may I ask how to adjust the tension and bearing shell clearance, and what is the principle behind it? How to adjust the concentricity of the bearing and shaft? Thank you
When you disassemble the sliding bearing body, there are shims at the joints, and these shims are used to adjust the clearance between the bearing shells and the shaft. During adjustment, it is essential to take accurate measurements, and these should be taken with the bolts fully tightened, while measuring the compressed wire. The diameter of the wire to be used is determined based on the clearance of the bearing bush. For the measurement method, use glycerin to attach the wire to the top of the shaft \"radially perpendicular to the ground\"; after tightening the bolt, remove and measure the wire. Be sure not to use lead wire with an excessive diameter, otherwise it will damage the tile. This is just a simple measurement; it’s best to carry out these techniques on-site. Otherwise, adjusting the surface treatment of the bearing shells – a process known as \"shelling\" – requires certain technical skills. It’s best not to try to fix it by yourself; low-speed devices are okay, but damage to high-speed devices can happen in an instant.
The lead compression method is more accurate than using a feeler gauge for measuring bearing housing clearance, but it is more labor-intensive. The aluminum wire used for testing should be soft, and its diameter should not be too large or too small; the ideal diameter is 1.5 to 2 times that of the gap. In practical applications, soft lead wire is usually used for testing. During testing, first open the bearing housing cover. Select a lead wire of appropriate diameter, cut it into segments 15 to 40 millimeters long, place them on the shaft journal and at the interface between the upper and lower bearing housings. Then close the bearing housing cover and tighten the fixing bolts to the specified torque. After that, loosen the bolts, remove the bearing housing cover, and use a micrometer to measure the thickness of the compressed lead wire in order to determine the average value of the clearance at the top of the bearing housing.
The tension is measured as follows: after installing the properly treated bearing shells in place and tightening them, an appropriate amount of lead wire is placed on the back of the shells. Then, a copper sheet of the suitable thickness is applied to the contact surface between the bearing shell cover and the machine frame, after which the cover bolts are tightened. Then release the gland and measure the thickness of the lead wire minus the thickness of the copper sheet. Negative values represent tension, while positive values represent clearance 【Personal opinion only】