Anchor Block Requirement? 3

[yukon09]

Hi,
I am working on a 3 km tailing pipeline design for a mining operation. An anchor block is added to the end of the tailing pipeline near the pumphouse. PE asked me if we need another anchor block on the pieline near the tailing pond.
My understanding:
1. With another anchor block:
We will have both anchor blocks at the ends of the tailing pipeline. The pipeline is fixed between the anchor blocks. The thermal expansion will generate thermal stress on both anchor blocks.
2. Without another anchor block:
The pipeline will have a fixed end and a free end. The thermal stress will be zero (assuming no friction on the piping supports) but a displacement will be found at the free end.

My question is what is the rule to determine if the anchor block is required or not.
Any reply will be appreciated greatly!

 

[C2it]

Is the pipe buried ? If not, what supports are used ?

If buried, you would have a 'virtual anchor' in the u/g anyway. If above ground and you don't mind a bit of movement at the pond, why restrain it and cause possibly big forces ?

Probably best to let it move and adaquately guide it ?

 

[pennpiper]

What is the pipe material (Carbon Steel, Cast Iron, HDPE, etc.)?

What is the joining method for the pipe (Butt-Weld, Mechanical Joint, etc), ?

 

[yukon09]

Morning, C2it and pennpiper,
Thanks for your prompt reply.
The 8" pipeline will be above ground and with the guide to support it.
Pipe materials is PE. I don't know why it isn't HDPE and the pressure is 135 m.

 

[yukon09]

Another question: how to design anchor block for PE pipe?
I know some kind of anchor block for carbon steel pipe. They were welded on the anchor directly or built in a concrete block.

 

[BigInch]

If there is no equipment sensitive to movement nearby, there is usually no need to provide an anchor. Anchors and guides convert pipe movement into stress. If there is no problem with allowing the predicted movement, let it move.

Here's the best procedure,

1.) Increase pipe flexibility if possible, which will tend to increase general pipe movements thereby reducing forces and stresses BOTH within the pipe and on the equipment.

2.) If increasing flexibility results in pipe movements towards equipment or other undesireable movements, consider adding an anchor block or other guides or stops that limit those movements.

In general, adding an anchor block or guides and stops tend to increase pipe stresses, which may also increase equipment stresses or perhaps could reduce equipment stresses in one place and increase them in another. Therefore increasing flexibility is normally the preferred option.



**********************
"Pumping accounts for 20% of the world’s energy used by electric motors and 25-50% of the total electrical energy usage in certain industrial facilities."-DOE statistic (Note: Make that 99% for pipeline companies)

http://virtualpipeline.spaces.live.com/

 

[yukon09]

I got much more information from P&ID:
A 8" PE tailing pipeline is from a pump house to a tailing pond. One end of the pipeline is connected to carbon steel pipe and another end is free.
Another 8" PE reclaim water pipeline is from a pump in the tailing pond to a tank. Both ends of the pipeline are connected to carbon steel pipe.
The two pipelines have the same route and all are above ground.
My thoughts:
Add one thrust block to the joint of PE tailing pipeline with carbon steel pipe.
Add two thrust blocks to both ends of PE reclaim water pipeline.

 

[BigInch]

I guess I don't understand what equipment that is sensitive to movement you have at the tailing pond.

**********************
"Pumping accounts for 20% of the world’s energy used by electric motors and 25-50% of the total electrical energy usage in certain industrial facilities."-DOE statistic (Note: Make that 99% for pipeline companies)

http://virtualpipeline.spaces.live.com/

 

[yukon09]

BigInch (Petroleum) 25 Jul 09 22:47
I guess I don't understand what equipment that is sensitive to movement you have at the tailing pond.:


The reclaim water is taken form the tailing pond by a pump and sent to a tank. It means the reclaim water pipeline is connected to pump discharge nozzle and tank nozzle.

 

[BigInch]

Oh. OK.

**********************
"Pumping accounts for 20% of the world’s energy used by electric motors and 25-50% of the total electrical energy usage in certain industrial facilities."-DOE statistic (Note: Make that 99% for pipeline companies)

http://virtualpipeline.spaces.live.com/