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# Removing air from underwater pipelines2

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## Removing air from underwater pipelines

(OP)
I am in need of urgent help.

Can anyone please tell me how is the air removed from a offshore pipeline?

The air that gets accumulated within a pipe pumping liquid and since the pipe being below over the sea bed how do we remove the accumulated air from it?

For instance if the pipe is above over the land we use air valves to release this air similarly how do we do that when the pipe is underwater?

Sarvesh Rahate
Water & Wastewater Engineer

### RE: Removing air from underwater pipelines

2
Pump faster.

Depending on your angles of the pipe you normally need about 1m/sec or faster velocity in the liquid to "blow out" or entrain all the air in the liquid.

Nowhere near enough information here to offer much more advice or comment.

try adding
#Service
~Fluid
Size of pipe
Flow rate / velocity
Length
why is this an issue
A diagram / profile sketch
pressure
end connection

The more info the better

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

### RE: Removing air from underwater pipelines

(OP)
Thank You LittleInch.

The fluid velocity within the underwater conduit is around 0.7m/s.

The main issues are:
1. The incoming flow at the particular pump station is low.
2. We have very less chance of reducing the diameter.

In this case is there a way out of the removing the air within the pipeline. Can this be done using valves or some other air removal mechanism? Is there any other alternative?

Awaiting for you reply!

Sarvesh Rahate
Water & Wastewater Engineer

### RE: Removing air from underwater pipelines

Well answer a few of the questions I asked and we might get somewhere.

However a 0.7m/sec I would imagine if this is a fairly gently sloping pipeline that the air has already been removed.

I ask the question again - why do you want to know / is there a particular problem?

Can you pig the line? That would sweep it out, but water / waste water lines tend not to include pig traps.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

### RE: Removing air from underwater pipelines

(OP)
The details are as follows:
1. Service (Fluid) : Untreated Sewage (Wastewater)
2. Size of the pipe : 180 NB
3. MOC : HDPE
4. Flow / Velocity : 12 l/s / 0.7 metres per second
4. Length : 2000 meters
5. End Connection : Open to Atmosphere
6. Profile: Indicative (See attached)

I hope I have answered all the questions with all the information that I have.

Sarvesh Rahate
Water & Wastewater Engineer

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