Is a Bi-Solvent Cleaning System a Good Option for Critical Cleaning?

In the world of vapor degreasing, there are four types of solvent degreasing systems: monosolvent cleaning, azeotrope cleaning, co-solvent cleaning and bi-solvent cleaning. Of them all, bi-solvent cleaning is perhaps the most complex but also the most powerful. Here’s how it works:

In general, the MicroCare monosolvent fluids or azeotropes can perform all of the required cleaning jobs. But once in a while a customer has a particular contamination that can’t be managed by a single solvent or azeotrope. This can happen because of materials compatibility issues, throughput issues or maybe environmental regulations. In this case, you are going to need to add cleaning power without using banned ingredients.

A co-solvent system might fix the problem by adding a strong, non-volatile solvent to the boil sump of the degreaser. But this is limited by the temperature of the rinsing fluid. If the rinsing fluid boils at 40˚C, and the contamination needs to be at 100˚C to be cleaned, no amount of co-solvent scrubbing is going to get the job done.

Therefore, once in a great while, customers need a second machine which operates at much higher temperatures. This will deliver approximately the same convenience and speed of traditional solvent cleaning, but amplified by the second solvent and much higher temperatures. This bi-solvent provides the additional muscle or horsepower that the application requires.

How Does It Work?

The two solvents have very different behaviors. The bi-solvent cleaning fluid is outside the degreaser, in a separate cleaning tank, and usually operates at much higher temperatures. These are usually highly aggressive but slow-drying hydrocarbon solvents.

Meanwhile, back in the vapor degreaser, the HFC, HFE or HFO rinsing solvents will boil at a low temperature (like the MicroCare™ and Vertrel™ solvents). They are primarily used to rinse the bi-solvent from the parts.

The MicroCare Carbon Steel Cleaning Fluid is a bi-solvent cleaning product, engineered for maximum cleaning and maximum environmental protection. It is a two-part, nonflammable, non-chlorinated, multi-function cleaning fluid engineered for use in high-temperature dip tanks. A vapor degreaser and is used to rinse the bi-solvent off the parts. The bi-solvent fluid is collected in the distillation phase of the rinse degreaser and usually can be recycled and re-used, which saves money.

Together, the system delivers excellent cleaning on all types of solder fluxes, oils, greases, waxes, and particulates, paints, buffing compounds and anti-rust agents. It is highly compatible with most metals, plastics and ceramics; it also has and broad compatibility with plastics and elastomers. The downside of bi-solvent cleaning is the requirement for a separate cleaning tank, the higher temperatures it requires, and the reduction in through-put from an extra cleaning cycle. On the other hand, it delivers excellent cleaning without water or other problematic cleaning products.

In summary, a co-solvent system can be used only for the most difficult soils, which often require high temperatures for removal. In the right application they can provide superior cleaning results without the throughput delays inherent in aqueous systems.