When the variabilityof a variable springexceeds the MSS standard of 25%, the designer's first option would be to lowerthe spring rate so that the difference in load with the same amount of movementwould be smaller than that associated with the higher spring rate. The designerwould continue this exercise until a variability factor of less than 25% isachieved.
What position should a variable spring be adjusted to before the pipeline is put back into service after a shutdown?
Thevariable spring should be restored to its original installed (cold) position.
Variable Spring with White Diamond Indicating Cold Position
What are spring support jacking bolts?
A spring support jacking bolt is a variable spring accessory that aids inremoving the upper limit travel stops. They are usually used in applicationswhere large installed loads are present. They are located directly above theupper travel stop. By tightening the jacking bolt, the installed load can bemore easily transferred to the spring load column.
F-Type Variable with Jacking Bolts
What are the sizes of spring supports?
For variable springs there are 23 sizes with loads ranging from 50 lb. through 50,000 lb. For constant springs, there are 110 sizes with travel ranging from 1″ to 14″ and loads ranging from 0 lb. to 90,000 lb.
PTP-8 Type C Variable Spring Assemblies
Figure 100 C-Type Constant Springs
PTP 100-C Size 84 Constant
How do you read the load indicator on a spring support?
To read the load indicator on a variable spring support, you need to read the measurement aligned with the bottom of the spring load indicator.
How much weight can a spring support?
The maximum load that a standard variable spring can support is 50,000 lbs. The maximum load that a standard constant spring can support is 90,000 lbs. A big ton spring support can be be used for loads greater than these standards.
Constant Spring Designed for a 35, 144 lb. Load
How do I check the load setting of a spring support?
To check the load setting, examine the position of the bottom of the load indicator with respect to the scale on the spring’s tag. Read from the bottom of the load indicator to determine position. Next, look at the size of the spring located on the tag. Then, refer to the appropriate load and travel table (Constant Load & Travel Table or Variable Load and Travel Table) to determine the respective spring rate and the “0” load (minimum working range load). Multiply the spring rate by the position value and add that to the “0” load value.
What is the maximum load variability of a variable spring hanger?
Per the MSS standards, the maximum recommended variability for a variable spring hanger is 25%. If required, you can specify a variability less than 25%.
Variable Spring and Cro-Moly 3-bolt Clamp
What does travel mean when discussing spring supports?
When dealing with variable spring supports, travel refers tothe amount of deflection from our installed position to our operating position.When dealing with constant springs, travel refers to the total amount ofdeflection, which could be accommodated by the support.
What are spring cans?
“Spring can” is the general term used to describe either variable or constant spring supports.
Custom Spring Can with Slide Plates