Better Leak Detection
June 4, 2009
Optinova (Godby, Finland), a manufacturer of intravenous catheters, has installed in-line leak detection equipment into its production process for catheter tube manufacturing. The thin wall tubing is used for nutrition and blood transfusion delivery systems. Optinova called in Adixen Scandinavia (Linköping, Sweden), a leak detection company, to assist them with the challenging task of developing a system to identify pinholes in the tubing while it was being formed. Installing in-line leak detection would reap huge benefits by eliminating secondary after-process testing.
The approach that was discussed and agreed to by both parties was to have the tube formed in a cloud of diluted hydrogen tracer gas and then passed through a specifically designed accumulation chamber at line speed. Diluted hydrogen as a tracer gas-95% nitrogen, 5% hydrogen-is nonflammable, inexpensive, readily available and environmentally friendly.
Minor defects such as pinholes in the tube would be identified by a detector that continuously monitors the chamber for the presence of hydrogen leaking from the tube into the chamber. A signal would be given from the detector to the tube manufacturing process if a leak were detected. Then the line would be stopped and the faulty section cut and removed. The process would then continue. The highly sensitive hydrogen leak detector H2000 Plus was chosen for the task.
The H2000 Plus leak detector has a sensor (Gas-FET) that is specific to hydrogen, high leak rate sensitivity (5 x 10-7 cc/second) and requires no scheduled maintenance.
A prototype test system was designed and delivered to Optinova by an Adixen application specialist and set up to run a few tests under the direction of Roger Andersson, manager of development and engineering at Optinova.
“The test results showed that the system worked brilliantly,” says Andersson. Adixen aimed to build a final engineered solution based on the initial prototype findings and to repeat the testing during a longer period of time. The new system was installed onto one of the tube manufacturing lines and run continuously.
“Adixen did a great job,” says Andersson. “Of all the equipment we have purchased in our manufacturing process, the tube leak tester was the one we have had to do the least adjustments to, which is really high praise.” Optinova has now invested in seven tube leak test systems from Adixen, one for each tube production line, resulting in quality tube production at line speeds.
Alcatel Vacuum Products Inc.