• Created : 
  • Modified : 
  • Category :  Agilent Knowledge Portal
  • Entry Type :  Article
  • Product Type :  Analytical LC Systems GPC/SEC Solutions Preparative LC Systems
  • Component :  LC Pumps
  • Product Name :  1100 Series LC System 1120 Compact LC 1200 Series LC System 1220 infinity II LC System 1260 Infinity II Bio-Inert LC System 1260 Infinity II LC System 1260 Infinity II Prime Bio LC System 1260 Infinity II SFC System 1260 Infinity II SFC/UHPLC Hybrid System 1260 Infinity III Bio-Inert LC System 1260 Infinity III LC System 1260 Infinity III Prime Bio LC System 1260 Infinity III Prime LC System 1260 Infinity LC System 1260 Infinity II Prime LC System
  • Task :  Troubleshooting
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Continuous Air Bubbles Observed in Waste Tubing on Manual Purge Valve

Answer

This Information Applies To: Agilent LC pumps with manual purge valve.

Issue

A good practice before using a system is to purge the system to remove air. This is done by observing the clear tubing from the solvent bottle as well as the waste line from the purge valve, until no air bubbles are noticed. There have been cases however, when the user will observe a continuous stream of air bubbles exiting the purge valve waste line even though no bubbles are observed in any of the lines from the solvent bottles.

Background 

The user assumes that the bubbles are coming from the pump and will continue to purge for some time without the bubbles being reduced. These bubbles can in fact be caused by air leaking into the waste tubing if the waste tubing is not fully seated and sealed onto the purge valve waste connection. This intake of air occurs due to the Venturi effect.


Flow through Quat Pump.
Figure 1. Flow through Quarternary Pump
1. Solvent bottle tubing, 2. Degasser, 3. MCGV (Multichannel Gradient Valve), 4. Purge Valve, 5. Purge valve waste tubing

Resolution 

  1. Check and verify if the purge valve waste tubing is only attached up to the lower position 1 of the purge valve barb fitting (see Figure 2).
  2. If true, then remove the waste line, carefully trim the waste tubing back 2 to 3 mm using a tubing cutter, making sure to leave a straight clean edge on the tubing. Tubing cutter (p/n 8710-1930) is perfect for this task.
  3. Re-attach the waste tube on the barb fitting by pushing it further up to position 2. To better grip the waste line, you can grasp it with a piece of sandpaper or some gritty material to allow better traction when pushing it onto the barb fitting.

 

  
Warning: Take care when cutting the tubing to cut on a firm cutting surface and take care to avoid any injury from using a sharp cutting blade. Follow your organizations safety protocols and wear appropriate Personal Protective Equipment if necessary.

 


Purge Valve
Figure 2. Purge valve schematic
1. Incorrect Waste Tube Location, 2. Correct waste tube location

 

 
Learn how to effectively operate your Agilent 1260 Infinity LC system with OpenLab CDS: 
Agilent 1260 Infinity LC system with OpenLab CDS e-learning path available from Agilent education

 

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