Monday, October 21, 2013

[MW:19026] Re: Presuure test with Hydraulic Oil.

hi,

Things you can tell your Sub-contractor,

1. Calculate Total volume Oil required in pipeline(perhaps u have)
2. Calculate Oil volume required to raise pressure 1 bar
3. Calculate pressure change for 1degree temparature change.
4  Plot PV diagram to chek relataion between pressure and volume.

If everything matching as near with this scientific result you can accept or else ask to check for air pocket inside pipeline.

regards,
mohd.



On Monday, October 21, 2013 5:54:17 AM UTC+1, Airon wrote:
Dear Folks,

Been doing pressure test  (different pressures ranging 450 - 7500 psi)  for Hydraulic piping (18-30 mm dia). 
Never had a satisfactory graph. 
Theres a sudden initial drop (mostly) or rise after pressuring. 
During holding time the rise or drop in pressure relative to the atmospheric temperature variation is too much. 
Tried the same test early morning , midnight mid noon and all different times, results are weird graphs.
Subcontractor is not giving a convincing explanation and insists its a normal thing for hydraulic pressure tests. 

Is it normal?
does anyone else have similar experiences or any presentable explanations?

Regards

Airon

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