Multi-solvent washing

Over the years, environmental regulations in several countries have increasingly motivated the dry cleaning industry to use more environmentally friendly but combustible solvents as an alternative solution to perchloroethylene. Almost all chemical suppliers have developed their own solvent systems, and most of the new alternative solvents are based on modified hydrocarbons and alcohols, in different formulations, with a cleaning power (KB) in some very close to and even higher than that of perchloroethylene itself.

This increased availability of solvents on the market has made it more complicated for practitioners to choose the optimal cleaning system for their use. This also strongly motivated the decision to create a MULTI-SOLVENT line, as a flexible tool that can be adapted or easily implemented to operate the Firbimatic machine with all solvents available on the market.

To date, our machines can run with solvents such as Hydrocarbons, GreenEarth (silicone-based), Intense, Higlo and Sensene giving the possibility to the operator, after proper internal cleaning of the machine itself, to be able to change solvents through a simple operation of adjusting parameters and settings based on the different properties of the solvents.

Depending on the different boiling point of the solvents we have to increase/decrease the distillation heating temperature, and similarly depending on the different drying temperature recommended at the inlet of the washing basket we have to adjust the temperature setting itself accordingly.

Properties of new solvents

One of the main differences between the use of perchloroethylene and alternative solvents is flammability. Unlike Perchloro which is a non-flammable solvent the other alternative solvents are flammable and require Class IIIA equipment with safety precautions.

Class IIIA solvents have a flash point at/above 60°C and below 93°C.

This means that the machines must provide adequate distillation performance and in compliance with the highest safety standards. To do this, we use the UNDER VACUUM DISTILLATION system by installing a dedicated vacuum pump in order to reduce the boiling point inside the distillation chamber and enable the distillation process to be carried out under optimal and safe conditions.

In order to also ensure a safe drying cycle, during this phase the machines are designed to work below the flammability limits of solvents and make use of ETL/Intertek certificates to this effect. We can therefore say that during the drying cycle the machine always works below 25 percent of the LEL. (Lower explosion Limit)

FRACTIONAL DISTILLATION is designed to maintain good water control in the circuit.

The first part of the distillation carries most of the water/moisture, while there is very little moisture in the remaining part of the distillation. The idea of fractional distillation is to separate the distillation into two stages. The first part carrying the moisture is sent to separator No. 1, the solvent will be stored there waiting to be used in the next cleaning cycle.

In this regard, a small amount of water is recommended to treat water-soluble stains such as salts, sugar, sweat and urine. Surprisingly, hydrocarbons seem to be much more tolerant of moisture in the system than perchlorine or fluorocarbon, so the risks of shrinkage from felting of wools or graying of white cotton seem to have been reduced. Thus, the aim at this stage is to isolate the water/moisture in separator 1 and prevent water from ending up in the solvent tanks.

The second part is sent to separator No. 2, and once it reaches a certain level it is transferred to separator 3, which has the function of a decanter for further separation of the solvent and water, which is actually in a minimal amount. The cleaned solvent finally reaches the storage tanks.

Another characteristic of the new alternative solvents is the ODOR of the solvent itself. One of the major concerns faced by dry cleaning workers in the transition from perchlorine to alternative solvents is machine maintenance. A bad odor can develop in alternative solvents in a machine that is improperly or inconsistently maintained.

The water separator and also the solvent storage tanks is where bacteria on clothing can accumulate. Bad odors can also develop from the possible amount of water accumulated in the solvent tanks because it is responsible for the formation of bacteria.

The process of continuous distillation with fractional distillation and appropriate separation , perhaps with the addition of specific antibacterial product (as recommended by the totality of chemical suppliers), already allows to better manage the water in the system.

SELF-CLEANING TANKS make it possible in the first place to avoid the accumulation of dirt or bacteria in the solvent tanks, which could be responsible for bad odors. In fact, the solvent tanks in the F series are designed with a round shape, greatly improving the self-cleaning action; in fact, the solvent is pumped at high pressure from above, creating a kind of vortex flow inside the body of the tanks and keeping the walls completely clean. In addition, there are no corners possibly subject to dirt/bacteria accumulation.

AUTOMATIC REAR DRUM CLEANING then completes the picture of eliminating dirt/bacteria accumulation, obviously in a different position on the machine. So, we are not only keeping the solvent tanks clean, but we have also implemented a system to keep the rear drum area of the machine clean.

With this system, the solvent enters with pressure from the back of the drum, and by cleaning the entire area every cycle, it allows us to reduce lint buildup in the back of the drum and drum. The benefits of this simple system are many: improved solvent cleaning and better fabric cleaning results, reduced odor, and improved garment drying performance.