Dear all,

In Anvil Catalogue Model R Constant Spring - Page 150(the one we will use)
Topic: Mathematically Perfect Pipe Support

L = KY(Z/W)
Constant Load = Spring Stiff * Travel * ( dim Z/ dim W)

Since equation holds true for all positions of the load within its travel range and “K”, “Y”, “Z”, and “W” remain constant it is therefore true that perfect constant support is obtained.
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We plan to use existing constant spring at same node (so in Caesar we predefined constant load same as existing), at modified existing pipe routing. We have checked no big impact load to closer supports.

Output Caesar II: The travel is below the existing, it will be OK to use existing support? Please advice.

I think for lower travel, dim Z will play to higher value, so they will fit the equation in Anvil catalogue? Please advice.

I do not thing there will be a problem as long as the load (which includes the ancillaries) remains the same at the support point. The travel at this location is affected by the behavior of the remaining of the pipe.

You can check this by letting Caesar II select the support type and/or spring rate. It will end up with the same constant load support.

Thanks Demir,

We have tried not to predefined Constant Load, for modified routing, and let Caesar did sizing. For that, we had constant load raise from 1200 kgf (existing, travel x mm) to 1300 kgf (new, travel lower than x mm).

As we will try not purchase the new one, then we did by predefined 1200 kgf (we had travel still lower than x mm). I think delta 100 kgf is still acceptable. please advice...

Another interesting in mathematically. Quote from anvil catalogue:
Since equation holds true for all positions of the load within its travel range and “K”, “Y”, “Z”, and “W” remain constant it is therefore true that perfect constant support is obtained.

Constant Load = Spring Stiff * Travel * ( dim Z/ dim W)

Do you have an idea which parameter suit the equation, in case how constant spring have result in constant load in vary of travels 0 mm to x mm. I think it is "dim Z" play the role not dim "W". Actually I want to know for sure.

Constant Hangers are not really "constant", the load can vary by as much as 6%. Call your vendor and discuss this.

You may be able to correct the loading on the constant load hanger by playing with the locations of the nearby supports or changing the route of the pipe slightly. Other than those you have only one option, as Richard suggested, talk to the supplier for the acceptability of the hanger for the new load and displacement.

Noted that Richard.

Regarding Caesar output, One constant spring shall give constant support load along travel (in all NATIVE/BASIC load cases)? Please advice.

I get what you mean it will respond well 6% variation of constant load written in name tag when we moved it to another case. CMIW sir..

The actual hardware may develop up to 6% variation in load through its travel but in CAESAR II a "constant support hanger" is modeled as a constant force with no variation through its travel. Look at the restraint summary for these "restraints" - the same number appears for every load case.

Thanks Richard, Dave, Ibrahim.