The Monitor

Production Process Insights

Maximize Your Low-Emission Gas and Liquid Samplers' Output

Posted by George Buss on 2/17/20 8:00 AM

Low Emission Samplers

Low-emission (low-e) closed loop gas and liquid sampling systems are simple, safe and accurate ways to manage representative sampling in your plant. But even the most reliable sampling solution will need ongoing maintenance and service. When your gas and liquid samplers aren’t working properly, these troubleshooting tips can keep your system running smoothly.

Low-emission (low-e) closed loop sampling systems are designed to help plant operators pull fresh material directly from the process flow to deliver a true representative sample from the system.

These low-e systems are safe and simple ways to deliver accurate test results that ensure the quality and consistency of the end product. They keep liquids and gases contained, and operators use a series of valves and vents to control the low e-sampling process. Plus, they’re easy to use and save a considerable amount of time without compromising the sampling process.

But even the most reliable low-e sampling solution needs ongoing maintenance and service. Troubleshooting should be a part of your regular maintenance plan. When these gas and liquid samplers aren’t working properly, knowing a few troubleshooting tips can keep your system running smoothly.

Troubleshooting your low-emission samplers

Manual Valve, Double (MVD) Panel 

Problem Solution
Sample is slow or has no sample flow 
  • Make sure the sample supply and return lines aren’t switched.
  • Ensure the sample bypass handle is correctly installed.
  • Adjust the sample flow control set screw.
  • Make sure the sample flow isn’t blocked by debris.
Sample flow enters the bottle too fast
  • Adjust the sample flow control set screw.
  • Check to be sure the flow control orifice is installed
My sample container retains pressure
  • Check to see if the vent line or needle is restricted.
  • Make sure the vent line check valve isn’t stuck closed.
  • Check the vent line back pressure.
My sample leaks from the sample needles during sampling
  • Make sure the needle is seated properly.
  • Ensure the needle retainer nut isn’t loose.
  • Check the needle and needle O-rings for damage.
My sample leaks from the sample needles after sampling
  • Make sure the sample valve isn’t returning closed.
  • Check the valve for seat damage.
My sample leaks from the vent needle after sampling
  • The sample container could be overfilled, forcing sample liquid into vent line.
  • Make sure the vent line check valve isn’t leaking back.
There is process fluid visible in the nitrogen flow meter
  • Make sure the check valve isn’t stuck due to debris.
  • Ensure the check valve seat isn’t compromised.
I am unable to purge
  • See if the nitrogen regulator pressure is set too low.
  • Check the nitrogen check valve and make sure it’s not stuck closed.
  • Make sure the sample pressure is properly vented.
My sample pressure back feeds through purge inlet line
  • See if the nitrogen check valve is stuck open or leaking back.

 

Manual Closed Loop, Gas (MCG) Panel

Problem Solution
There is low sample pressure or I am unable to vent sample pressure
  • Make sure the sample inlet line isn’t restricted.
  • Check to make sure the lines are connected correctly.
I can't switch between vent and sample mode
  • Check the tandem valve V-2, as it could be damaged internally.

 

Manual Fixed Volume (MFV) Panel

Problem Solution
Sample is slow or produces no sample
  • Check to make sure the sample supply and return lines aren’t switched.
  • Make sure the sample flow isn’t blocked by debris.
Sample flow enters the bottle too fast
  • Adjust the sample flow control set screw.
  • Check the nitrogen purge pressure, as it might be too high.
My sample container retains pressure
  • Make sure the vent line and needle aren’t restricted.
  • See if the vent line check valve is stuck closed.
  • Check the vent line back pressure.
My sample leaks from the sample needles during sampling
  • Make sure the needle is seated properly.
  • Ensure the needle retainer nut isn’t loose.
  • Check the needle and needle O-rings for damage.
I am unable to purge
  • See if the nitrogen regulator pressure is set too low.
  • Check the nitrogen check valve and make sure it’s not stuck closed.
  • Make sure the sample pressure is properly vented.
The sample pressure back feeds through the purge inlet line
  • See if the nitrogen check valve is stuck open or leaking back.

 

Sample Cooling Panel

Problem Solution
My sample is too hot
  • There’s not enough cooling water flow.
    • A 15 PSI differential pressure is required between cooling water supply and return.
    • Adjust the cooling water outlet flow control valve.
    • Check the sample cooler coils, as they might be fouled with sediment or calcium.
  • The sample flow is too high
    • Adjust sample flow control valve to reduce flow.
My sample is too cool
  • The sample flow might be too slow. Adjust the sample flow control valve to increase flow.
My sample cooler chatters or vibrates
  • There might be too much cooling water flow. Adjust the cooling water outlet valve to reduce cooling water flow.

 

Low-e sampling helps you capture representative samples simply, safely and accurately. Contact us at +1-262-567-7256 or complete our online contact form to discuss how Sentry low-e closed loop systems can help you achieve safe, simple and accurate sampling results.

Be Sentry Ready - Proshield Lifecycle Services

Topics: Hydrocarbon Processing, Upstream & Midstream, Liquid & Slurry, Gas

Written by George Buss

As one of our expert service technicians, George has been working on Sentry sampling products and systems since 2001. This means he has accumulated a wealth of knowledge and experience with Sentry sampling equipment, and is happy to share his knowledge with customers looking to ensure their sampling equipment is working optimally and efficiently. In his spare time, George can be found fixing stuff and making it work (which also sounds a lot like work, doesn’t it?)

Related Posts