suren12564
Mechanical
Why we are limiting variability of spring with in 25 percent. How does it affect if I choose a variable spring with variability exceeding 25 percent. Thanks in advance
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Why we are limiting variability of
- Thread starter suren12564
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Do the math. What happens if you set the difference in hot and cold to say 35%? I doubt if any reasonably designed piping system could handle such variations.
I’m not sure why the default industry was set to 25%, but it must have been chosen at some point by someone, and after that perhaps was accepted as the de facto.
I’m not sure why the default industry was set to 25%, but it must have been chosen at some point by someone, and after that perhaps was accepted as the de facto.
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suren12564
Mechanical
That is what I couldn't imagine and seeking explanation. How does it effect the piping system??
EngDesServices
Mechanical
Spring variability is the difference in loading divided by the operating load (typically (HL-CL)/HL).
As your variability increases, your distance of travel increases, altering the load on the pipe as governed by Hooke's Law (F=-kx). If the component being supported was to be designed for excessive travel using variable spring cans, then it is possible that you end up with a very large localized loading due to the spring becoming significantly compressed/tensioned.
From a practical perspective, constraining variability constrains overall spring movement and likely increases the lifetime of the component. A spring can with a large movement will likely fail sooner than one with a shorter movement when factoring in site conditions like temperature and corrosion.
For systems that have large piping displacements that would otherwise become over-stressed by constraining displacement, like cokers, we've always used constant rate spring hangers.
Michael Hall, PE (TX) PMP - President
Engineering Design Services LLC
As your variability increases, your distance of travel increases, altering the load on the pipe as governed by Hooke's Law (F=-kx). If the component being supported was to be designed for excessive travel using variable spring cans, then it is possible that you end up with a very large localized loading due to the spring becoming significantly compressed/tensioned.
From a practical perspective, constraining variability constrains overall spring movement and likely increases the lifetime of the component. A spring can with a large movement will likely fail sooner than one with a shorter movement when factoring in site conditions like temperature and corrosion.
For systems that have large piping displacements that would otherwise become over-stressed by constraining displacement, like cokers, we've always used constant rate spring hangers.
Michael Hall, PE (TX) PMP - President
Engineering Design Services LLC
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