Production Leak Detection Systems

Traditional Methods:

This section will explore the two (2) traditional leak testing methods offered by FTI:  Immersion and Sniffing.  

Immersion:

The traditional technique of leak detection called immersion involves immersing a charged or pressurized part.  Often called "bubble testing" or "dunking," immersion is a relatively primitive form of leak detection.  This method relies solely on the operator to visually detect bubbles coming from leaks in the part.  This introduces operator dependency, thus the increased possibility for error.  Small leaks are possible to detect, but very difficult.  This technique features an accuracy in the 10^-3 std. cc/sec range in high volume production applications, however it is not recommended.  Immersion is a very economical leak testing method.  However, disadvantages range from a relatively low sensitivity, high operator dependency, and possible part contamination, to fluid waste and the possibility of having to dry parts after testing.

Sniffing:

The sniffing technique of leak detection utilizes a detector probe to sense leaks.  This method is very operator dependent, in that the probe (or wand) is moved over the part and detects the leak as it passes over the leak.  The speed, distance from the part, and sensitivity of the probe determine the accuracy of leak detection.  However, sniffing will locate a leak on a part, unlike the other methods described, and has the ability to sense leaks as small as 10^-6 std. cc/sec.  Sniffing is NOT recommended in a high volume production environment, other than for locating leaks on re-workable parts.  Sniffing involves a relatively low tooling cost investment, representing an economical method of leak detection.  Disadvantages include a high chance of missing leaks due to operator dependency, fragile equipment in rugged environments, rejecting good parts (because of the inability to quantify the leak) and it is NOT a good overall leak detection technique.