×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Landfill Gas Condensate Liquid Level

Landfill Gas Condensate Liquid Level

Landfill Gas Condensate Liquid Level

(OP)
I need to measure the depth of the liquid in a landfill gas condensate sump that is under vacuum.
The sump is underground. Deposits are of concern.
I am new to vacuum applications. Thanks in advance.

RE: Landfill Gas Condensate Liquid Level

1. bubbler
I presume a vacuum pump is pulling the vacuum.

If the vacuum can tolerate a small amount of air, then a bubbler with an ultra low flow constant flow regulator can supply a low flow of air (or bottled nitrogen if air is problem) through a dip tube/pipe inserted into the liquid.

A differential pressure transmitter high side connected to the dip tube with its low side connected to a 2nd pipe/tube that connects to the non-liquid vacuum space will report the level in units of water column: inches or feet of water, or mm or m of water.

Level done by differential pressure assumes a constant density. Any change in density from the design density results in a proportional error in the reported.

2. Ultrasonic does not work in a partial vacuum.

3. Non-contact radar or guided wave radar will work in a vacuum.

RE: Landfill Gas Condensate Liquid Level

(OP)
Thank you danw2. The vacuum is created by a centrifugal blower that draws gas from the landfill.

RE: Landfill Gas Condensate Liquid Level

If you pursue bubbler technology, be aware that a tube perpendicular to a flow stream with the flow flowing across the tube opening is subject to a venturi effect and will read a lower pressure than the real vacuum pressure. A lower-than-expected pressure on the low side of a DP transmitter results in a reported level output with error on the high side. The error is likely to be constant when the pump runs, so checking the level between when the pump (blower) runs and when it doesn't (assuming the level doesn't change at that moment) will show you the magnitude of the error.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members! Already a Member? Login



News


Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close