Drain rate of declined safety valve outlet line
Drain rate of declined safety valve outlet line
(OP)
Hello,
I want to get a estimate on how fast the outlet line of a safety/relief valve is drained. The outlet line is rather long and the fear is that the bellow can get damaged if the valve experience a subsequent opening. The medium is water (cold)
Can anyone point me in the right direction about drain rates of sloping pipes or in other way help?
Thanks
I want to get a estimate on how fast the outlet line of a safety/relief valve is drained. The outlet line is rather long and the fear is that the bellow can get damaged if the valve experience a subsequent opening. The medium is water (cold)
Can anyone point me in the right direction about drain rates of sloping pipes or in other way help?
Thanks





RE: Drain rate of declined safety valve outlet line
Only put off until tomorrow what you are willing to die having left undone. - Pablo Picasso
RE: Drain rate of declined safety valve outlet line
Meanwhile, what I expect is this.
1) at t=0 the pipe is filled with water. The upstream end is a dead-end (closed safety valve).
2) for t>0: Air "bubbles" up at the top part of the pipe towards the closed safety valve. At the same time the water drains in the lower part of the pipe. At some point in time the air reaches the closed valve. At that point the pipe is almost completly filled with air.
This is a non-steady behaviour. Is there more simple equations that describes this event or is some kind of code required that handles two-phase flow?
RE: Drain rate of declined safety valve outlet line
Only put off until tomorrow what you are willing to die having left undone. - Pablo Picasso
RE: Drain rate of declined safety valve outlet line
BigInch, I agree that the depressurization rate should be very fast and not important to the total time it takes to drain the outlet. I would guess that the outflow from the pipe would be less intermittent than that from a coke bottle.
Anyhow, if anybody has a way to guesstimate this value I would appreciate it. Due to a small (gas) overpressure in the outlet line a drain next to the outlet of the valve (air intake) is not preferred.
RE: Drain rate of declined safety valve outlet line
Only put off until tomorrow what you are willing to die having left undone. - Pablo Picasso