Drawback mixing chamber

Despite its efficacy, Sandia foam has a number of drawbacks for field use by the soldier. First, it must be stored as separate components, which would require a rapid, personal, on-site mixing chamber for combining the two solutions. Second, the presence of hydrogen peroxide, a strong oxidizing agent, precludes its use near the eye, and would create much discomfort if used in a wound (Watt et al., 2004). To partially address these concerns, Sandia developed the formulation DF-200, which in part contains less hydrogen peroxide and surfactant. 

Regarding segmented flow analysis, a relatively large de-bubbler is usually required and this device may act as a mixing chamber, thus impairing system performance. This limitation is typical of older instruments. The bubble-gating approach [23] can be exploited to circumvent this drawback, but it has not been universally implemented. 

Tacky materials tend to stick to rotors and mbdng chamber walls. This is one of the drawbacks in this type of mixing. When this happens, one has to cool the Banbury walls and rotors. This is a time consuming process and slows down production. Occasionally, use of an appropriate lubricant eliminates this problem. Examples of common lubricants are fatty acids and their metal salts or amides, polyethylene waxes, and silicone compounds. 

---