Why are some tail lifting lugs located in the middle, while others are above the skirt seat?
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By looking at some pictures of equipment lifting, I noticed that on some tower-type equipment the tail lifting lugs are located on the skirt base, but there are also cases where they are not located there. Why is that? What are the considerations behind this?
The first image shows a complete tower, with lugs at the top and a tail lift at the base; the first image does not represent a complete tower – it is likely a partially welded assembly on site, showing an axial lift rather than a tail lift
This post was last edited by deep*a on 2018-9-17 at 16:57. It is mainly the distance that affects the stress on the lifting lugs; moreover, the area indicated by your arrow in the second image is not a tail lifting lug – it is the main lifting lug.
The one in the middle is not an aft hook; it’s a shaft-type hook. As the name implies, an aft hook should be located at the rear
I see that some tail lifts have only one, while others have two. Is it because the design engineers are lazy, or is it to save materials?
Then why is this main lifting lug located at the head of the equipment? Why not on both sides of the device? Is it also to save materials?
It is related to the lifting of the selected heavy equipment. Often, after the equipment diagram is ready, the design institute, the installation contractor, and the manufacturer need to jointly determine the initial lifting method; thereafter, the design institute calculates the center of gravity for lifting purposes and designs the lifting lugs, while the manufacturer is responsible for manufacturing them.
What was said upstairs makes sense; I agree. . . .
Under normal circumstances, it is best to place it at the base ring area, as this part has high overall stiffness. Inside the base ring, steel tube supports in a linear or triangular shape should also be installed for reinforcement.
For the top lifting lugs and shaft hoists, the design is determined according to the customer’s requirements, with calculations carried out based on the stress analysis model. See attachment; it is inconvenient to install shaft lugs on the cylinder, or top lifting lugs can be considered for economic reasons.
The first diagram is roughly similar in shape to the high-pressure depropanization tower I designed recently. We have fixed the location of the main lifting lugs; the tail lifting lugs cannot be placed in the middle of the structure as they would interfere with the bolt holes, so they can only be located on the upper part of the skirt plate. However, I don’t know how to design such lifting lugs anymore. Could someone teach me?