Should the nut at the sliding end of the saddle be tightened?
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This post was last edited by huanghong on 2021-1-7 at 10:41. An oblong hole is provided in the bottom plate of the sliding end of the saddle, to allow for sliding as the horizontal container expands (or contracts) due to temperature changes. Should the nut at the sliding end be tightened? Obviously, it cannot be tightened too much; otherwise, the friction between the saddle bottom plate and the foundation (the embedded steel plate) becomes too high, preventing the sliding end from moving. Can the intended purpose of that design be achieved, and how can we ensure it is achieved? There are no requirements regarding the standards for the saddle (the installation party probably doesn’t pay attention to such standards either), so what should be specified in the design documents? No need; the installation and acceptance specifications for static equipment cover this. According to 4.4.4 of GB 50461-2008 \"Code for Acceptance of Construction Quality of Installation Engineering of Petrochemical Static Equipment\" (which is usually referenced in design documents), the anchor bolts at the sliding ends of horizontal equipment should be located in the middle of the oblong holes in the supports, with any positional deviation being such that it compensates for the expansion and contraction caused by temperature changes ； Clean the sliding surface of the bearing and apply lubricant ； After the piping for the equipment is completed, loosen the nut of the foot bolt at the sliding end support to create a gap of 1–3 mm between it and the support plate, then tighten the lock nut. Section 5.3.3 of SH/T 3542-2007 \"Technical Specifications for the Construction of Petrochemical Static Equipment Installation Projects\" also contains a similar provision: The contact surface of the sliding end support should be coated with grease. The distance between the anchor bolts and the ends of the corresponding oval holes should meet the expansion requirements. After the process piping is completed, loosen the nut of the sliding end support to leave a gap of 1–3 mm between it and the support surface, and then install a locking nut. This article was compiled and published by the WeChat official account “Rousseau Talks about Pressure Vessels”
According to the saddle standard, the sliding-end foot bolts of horizontal equipment are not positioned in the center of the oval holes in the support, but rather the position of these foot bolts is determined based on whether the equipment expands when cooled or when heated. For the sliding end foot bolt, the first nut should be tightened and then loosened by 1–2 turns before the second nut is tightened. Therefore, SH/T 3542 provides a more accurate specification.
The sliding saddle must ensure free sliding.
The bolt at the sliding end serves to provide positioning and guidance, facilitating sliding
This article was compiled and published by the WeChat official account “Rousseau Talks about Pressure Vessels”. It is recommended that the original poster indicate the source when reposting; thank you for your support
Once it is locked, there is no point in having an expandable hole for the shaft; one must be careful during installation, as workers often end up tightening it too much
After tightening to death, turn it 1-2 turns in the opposite direction; the worker hadn’t finished installing it, so they were told to continue. If it’s welded shut, cut it off and start over.