How do I tell if the source exhaust is blocked or flooded? What is the cause and how do I fix it?

日付: 09/13/2017
カテゴリー: Mass Spectrometers

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For research use only. Not for use in diagnostic procedures.


If your exhaust is blocked:

The typical symptoms of a blocked exhaust are that the Instrument Status is red and cannot be set to ready, and the exhaust does not stay on.

There could be several types of causes.

Visual causes:

  • Liquid in the venturi line
  • Liquid in the exhaust drain line
  • Kink in the exhaust drain line
  • Vapour lock due to a “dip” in the exhaust line

Audible Clue:

The Exhaust tries to start (you hear the gas flow) then quickly stops

Invisible cause:

  • Blocked/Clogged venturi: When the venturi line is blocked the pressure switch cannot stay activated, and the blockage cannot be cleared.  The venturi in this case is generally blocked after the exhaust/waste outlet.

If your Exhaust is flooded

The typical symptom of a flooded exhaust is that the Instrument Status is red and cannot be set to ready, and the exhaust does not attempt to come on.

There could be two types of causes.

Visual causes:

  • Gas flow:  If the gas pressure is too high, or too low, the exhaust will go to a fault state. This is because the pressure switch cannot manage the differential pressure.  
  • Line length:  Placing the gas regulator too far from the mass spectrometer.  The pressure and flow rate drops as the tubing length increases. Ideally, the gas regulators should not be more than 3 metres away from the mass spectrometer.  This provides the most ideal conditions for flow and pressure.

Invisible cause:

  • Blocked/Clogged venturi: The pressure switch does not activate, and there is a collection of condensed liquid in the collection box.  This means that you can visually see liquid in the drain.
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There are several ways to troubleshoot exhaust issues (apply to both blocked and flooded exhaust):

Visual inspection:

  • Are there any bends in tubing? Bends cause restrictions in the flow and pressure.  Watch for any locations where the line appears to have a “kink’ or a severe bend.
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  • Are there any dips in the gas line below the top of exhaust bottle? When the gas lines dip below the entrance of the drain vessel, this can generate a “vapour lock”, which results in fluid in the exhaust tubing being unable to flow into the exhaust bottle.
  • Is the source exhaust gas supply between 55 psi and 60 psi? Look at the dial on the regulator (manometer). The needle should be between 55 and 60 psi. If the pressure is too high, or too low, the exhaust will go into a fault state.  Adjust the regulator until the pressure is in the correct range.

Audio inspection:

  • Does the exhaust gas flow start when the instrument is switched from Idle to Ready? You should be able to hear the gas flow as a loud hissing sound.
  • Can you hear the solenoid at the back of the instrument switch? This means that the negative pressure is reached at the pressure switch. Even if the gas does not flow, you should hear the switch at the back of the instrument click as it changes position.

What can you do by yourself?

  • Clear bends in the tubing if needed.
  • Check the gas regulator at the wall and adjust if required.

When to call SCIEX?

If you follow the instructions above and still not able to resolve the issue please contact SCIEX Customer Care.