Flexible leak detection

Mass spectra of short-lived, unstable episelenides were obtained by taking advantage of a mass spectrometric technique developed for the time-resolved detection of transient intermediates in flash-photolyzed systems <66JA4277>. Detection does not depend on the electronic absorption characteristics of the transient, and, in combination with kinetic absorption spectroscopy, the technique assumes great flexibility. The apparatus consists, essentially, of a photolysis cell attached to a small leak into the ion source of an Atlas CH4 mass spectrometer. Selected mass peaks can be studied with a response time of a few milliseconds, and thereafter at times limited by bleeding of the photolyzed mixture into the ion chamber. Typical photolytic flash energies were 480 calories, passed into a reaction volume of 5 ml. 

Vacuum Leak Test. The vacuum leak test is similar in concept to the internal pressure leak test in that the result is a pass/fail for the detection of bubbles emanating from the package while submersed in a water bath. The method is described in ASTM D3078, Standard Test Method for Leaks in Heat-Sealed Flexible Packages. The pressure differential is obtained by evacuating the chamber, causing the package to expand. 

This system is ideal for thermoformed trays with porous lids and flexible pouches with one porous side. The test has been shown to detect leaks as small as 0.002 in. Guidmt and Medtronic have demonstrated the reliability of detecting leaks in blind tests and have quantified 100 percent of the purposely manufactured leaks in thermoformed trays (Hacked, 1996). In addition, there were no false positive readings in any of the unaltered packages. 

A fuel leak from the fuel supply pipework is foreseeable. It may arise following assembly, either when new or following maintenance, since the fuel pipework is routinely dismantled for turbine maintenance at intervals of one to three years. Gas turbines should operate without excessive vibration, and vibration detectors are often, but not always, fitted to larger units to detect bearing failmre. Such vibration could also cause fuel pipe joint failure. Catastrophic, sudden guillotine, pipe failure is very improbable, but a fuel leak from a control valve, flexible pipe, or flanged, screwed or welded pipe joint is a hazard against which appropriate precautions should be taken. 

Solution containers were obtained in which panel leaks (for the purposes of this paper, a panel leak is defined as a hole through the plastic film of a flexible container) had been detected at various points of the life of the product, such as during distribution or before patient use. The solution container was a two-chamber bag, with a peelable section separating the two chambers. In the finished product configuration, the two chambers are folded together, and packaged with the fold on the bottom of the carton. 

---