2 replies to this topic

[nipra03]

Hi,

 

 

I asked this before:

 

A question that comes up is relief velocities for liquids downstream of DANFLO type axially oriented  relief valve.

 By how much can velocities exceed the reccommended maxm. velocities of 20 ft/sec. ?

The relief line discharges into an atmospheric tank.

In one case the calculated velocity is ~ 54 ft/sec.

 

I know of issues related to vibration, noise and erosion but these seem to apply to steady state flow rather than intermittent transient flow such as relief lines.

Even if so, how would one design the piping to counter vibration and noise ?

I will appreciate any advice here.

 

My additional query  :

 

How will one calcluate reaction forces on the pipe due to this type of relief valve ? 

Will it be similar to the method given in API 521 ?

[PipingandPipeline]

Danflo has a spreadsheet with force calcuation, Danflo spreadsheet reaction force calculation is based on 2nd Newton's Law,

It may or may not be your case,

there are some different case when liquid relief into tank through pipe,

discharge pipe of Danflo valve pipe at initial condiation may be fully filled with liquid, empty, or partially filled with liquid,

you have to identify which is your case,

[nipra03]

Hi,

 

 I read this late - thank you for the answer.

 

Do you have the spreadsheet  - appreciate if you can send a copy .

 

Also you are very corrct indicating that the reaction force will dpend on the presence of liquid resistance downstream. Any suggestions here ?

 

regards