i have a process piping case study for following data.
code B 31.3
1. horizantal straight line of pipe between anchor A and anchor B =65 meters
2. material SA 106B ( 250 NB schedule 20)
3. design temp. 280 degree centrigate
4.design pressure 9 bar
5.fluid density 800 kg/m3
6. insulation thickness 100 mm
WILL ANYBODY please suggest suitable expansion joint,its type/ specification,no. of expansion joint,its preferred location from anchors, cost if possible so that the forces and moments on anchors are less.
also if possible give me few guidelines for the location of expansion joint in general cases.

thanks in advance

1. Ask client for preffered suppliers of EJ
2. Send sketch of layout to EJ manufacturer
3. Whilst waiting for reply, use google to find the EJ installation data on the net and spend 2 days reading it
4. Incorporate (EJ) comments into design.

Another post by somebody unskilled, asking for help with their homework or exam unwilling to do any study on their own tsk tsk!

In support of T.J.N.'s comment, "... spend 2 days reading it," it is very important to have a good understanding of expansion joint theory before you work on them. For example, EJ's can create very high anchor loads, they require proper guiding, etc. Be sure to get a copy of the EJMA (Expansion Joint Manufacturers Association) standards and guidelines and read everyting thoroughly.

Also, don't forget to specify the exact properties of the fluid in your spec. I know of one application installed recently in which several large-diameter EJ's began leaking within 6 months of installation because the corrosive nature of the fluid was not correctly specified.

Vijay,

Since the configuration you have mentioned is a straight one you are left out with two options. Use axial untied bellow which for a 250NB pipe size and 9 Bar pressure (hope this is operating pressure you are talking about)will create a axial pressure thrust of approx 6400kg on the nozzle, which most probaly won't be acceptable.

The second option is to go for in-line pressure balanced bellow. This will be costly but will have no additional forces on the nozzles due to pressure thrust.

Regarding number of expansion joints you have a total expansion of about 8.45inches. Normally maximum convolution readily available in market is 20nos which will take approx 3inches of expansion. In case you do not have any significant lateral or angular movement, the same 20convolution bellow will be able to take higher axial expansion. Most probably you will be able to do away with 2nos expansion joints at both ends with a physical anchor in the centre.

Regards
Krishnendu Bhattacharya.

Krish's responce has me thinking,


The actual (residual)pressure thrust is usually generated by the areas of the convolutions.

Modern bellows design gives small convolutions and hence small total pressure thrusts.

The pressure thrust generated by the process (50KN) will probably be acting on the back of the equipment and the back of the first bend.

any residual pressure thrust will be generated by the convolutions and will likely be very small.

Remember that the nozzle is designed to take pressure thrust anway (imagine a blank flange on the nozzle)

For your job, i would suggest a data sheet to the preffered supplier will yield a good response.

Vijay,

Rereading this topic today I realized that I forgot to ask an obvious question: Could you install an expansion loop between the two anchors as opposed to an EJ? A loop would be more reliable, more predictable, less expensive, and easier to guide than an expansion joint. In addition, depending on the size of the loop it could give you much lower anchor loads.