How do I know if the vent pipe or vent header is blocked?

[chemks2012]

Hi all

How would I check if my vent line or vent header is blocked?
Is there any cost effective technology that I can use to make sure if it's blocked or not? Do you think ultrasound or thermal imaging camera are useful?
Please note, the vent lines in questions are steam traced due to the nature of product vapour.

Thanks
KS

 

[pennpiper]

chemks2012,
You have not given us enough information.
1. What is the commodity in the line(s)?
2. Do these vent lines relieve to atmosphere or to a closed system?
3. Do these vent lines have any high point vent points or low point drain points?


Sometimes its possible to do all the right things and still get bad results

 

[chemks2012]

Pennpiper

Thanks for your reply. Below are the comments against yours.

1) material (vapour) is additives for polymer which melts at 60deg C and trace heating.

2)vent header is open to atmosphere.

3)vent header is slopped to the source tank/s and hence drain to the tank/s. Not sure if that's what you are after though.

Thanks
KS

 

[bimr]

A pressure difference across the vent should indicate plugging.

Use of a video camera periodically will also plugging to be observed.

Backpressure on the system will indicate plugging.

 

[racookpe1978]

How long is the pipe?
What is on the other end of the pipe? What is the process fluid or in the container that must be vented?
Can you get to the end of the pipe?
can you get to the beginning (tank) of the pipe?

Dangerous? Hazmat? Explosive? Shutdown or operating?

Why have you not run (1) a simple long wire or electrician's wire puller tape (100 - 150 foot are available) down the pipe? (2) a long boroscope or remote TV camera down the pipe?

 

[MJCronin]

Consider a video snake or similar system...

http://www.amazon.com/Video-Snake-SWJ-3188D-Inspection-Camera/dp/B0018CAB4E

Also, when the location of the plug has been determined, consider the installation of "break flanges" into a couple of loactions on the system to facilitate future cleaning.

A thermal survey of the system is easy and cheap and may also show you the location where the piping temperature suddenly drops..... that's where the plug is located.

As noted above, a removable pressure gauge may enable you to detect and graph an increasing backpressure in the vent.

MJCronin
Sr. Process Engineer

 

[georgeverghese]

Is the entire vemt system heat traced? How is temperature maintained in the drain tank?

 

[racookpe1978]

If the system is shutdown, and if the process can stand it, just pour water down the pipe outlet - with a person (using a confined space permit) looking at the pipe inside the tank.

If water comes through, the pipe is not blocked.

 

[Latexman]

Do you want to check if vent is blocked while running? Or, will the tank be shutdown for this check?

Good luck,
Latexman

Technically, the glass is always full - 1/2 air and 1/2 water.