Draining pipe after pumping

[Ali AA]

Hi. I would like to know how to discharge the leftover fluid in the pipe after pumping completed. After tank is fully loaded, the pump is automatically turned off. Thus, the fluid in the pipe stays there after pump stop. Is there any way to discharge the leftover fluid from the pipe?

 

[1503-44]

If it needs to be drained, you can install a valve for that purpose in the suction or discharge line, or in both.

--Einstein gave the same test to students every year. When asked why he would do something like that, "Because the answers had changed."

 

[pierreick]

Hi,
A simple PFD with equipment list will save words. What is the material and why do you need to drain the pipe?
More details better answer.
Pierre

 

[LittleInch]

Many systems don't need the pipe to be emptied.

If you do either drain it or blow it through

Need more details for sure.

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

 

[Ali AA]

We use the same line to pump two different fluids. The length of the pipe is 105 meters, while the diameter of the pipe is 20cm. After finishing the pumping of the first fluid, we dont want the second fluid to mix with the previous one. (Due to the price and quality differences). My point was how to discharge the leftover fluid from the first pumping operation. Thanks you for your attention.

 

[3DDave]

105m horizontally, but how high vertically? Seem like a separate small line with a suction pump at the far end to drain the main line is required.

 

[1503-44]

Slope the pipe to the drain point.

--Einstein gave the same test to students every year. When asked why he would do something like that, "Because the answers had changed."

 

[LittleInch]

For 105 m just install two lines.....

Draining lines or blowing them through still leaves some of the material left in the pipe.

Can you pig the line? Any 1.5D elbows? Any tees / changes in ID ? Any reduced bore valves?
You can buy pigging valves which use very small pigs for this.
How much contamination can you withstand?

Or just pump the second material and have a timer / flow meter and divert say 20 or 25m of the pipe to an interface tank and dispose of it.

All depends how often you need to change and the volumes you are pumping as to which is an option.

Some sort of sketch of your system with flowrates, volumes etc would help hugely.



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

 

[mk3223]

To switch the pump piping from one fluid to another fluid, you may need to to drain out the first fluid completely at drain connection at lowest piping location. And then, the pumping piping needs to be totally flushed and tested to ensure no cross contamination prior to using for the second fluid.

 

[pierreick]

Hi,
What is the level of contaminant you can accept?
Here you are talking about 3.3 m3 of liquid remaining in the pipe, is it worth to recover it?
Is there a payback if you add a dedicated line per product?
Can you flush the line with another product compatible with both products, let say a solvent or similar to reduce the threshold of contaminant, after draining or not?
More details better answer
Pierre

 

[AlmostRetired]

Can you simply blow the line through with compressed air into either the source tank or the destination tank?

 

[LittleInch]

Be very careful with air blow.

You need quite a high velocity to clear 99% of liquid and this has destroyed more than one tank in its time as the vents weren't designed for the volume flow.

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

 

[horacio Torres]

My friend

Without knowing details of this case, for sure is less expensive to install one line for each product compare to the risk of fluid contamination.

Horacio

https://www.linkedin.com/company/lagotuy/