A common misconception of some drycleaners is that because you have a light tank and dark tank on your drycleaning machine or a light machine and dark machine, you can let the solvent in those dark tank/machine get quite dark without having this darkened solvent affect your cleaning quality, because you are only cleaning dark colored garments, allowing you to change cartridges less frequently. While the dark machine or dark tank, does not have to be as clear as the light machine (which I would try to keep “water white”), the dark machine does have to be in such a condition that it is at least acceptable by DLI standards for solvent clarity, in order to prevent dye transfer problems.
You may have seen dark garments, such as black pants (which may have white lining, pockets and waistbands), that would seem they could be processed satisfactorily in darker colored solvent, but while the dark portions of these garments were just fine in appearance after processing, on the inside where the waist band/pockets used to be white, you now may have discoloration and dye transfer, due to poor solvent clarity/dye in the solvent. A problem that will be very noticeable to your customer. Any dark colored garment with white trim or components can also have this discoloration when cleaned in poorly maintained, dye laden, dark solvent. A problem that can be greatly reduced by changing your filters at the proper times.
While there could be a multitude of things that lead to the fugitive dye problems that a drycleaner may experience, for now I want to just focus on the life/mileage of an All Carbon Cartridge.
There are several factors that can affect the dye removal capacity of a cartridge filter. To name a few:
- the actual carbon volume of the cartridge filter
- the type and quality of the carbon
- the design of the cartridge.
- the amount of dye being released into the solvent
- the flow rate through the filter
Another item that should be taken into consideration is the recommended time between filter changes, by your machine manufacturer. When reading the maintenance sections of some machine manuals, equipment manufacturers may recommend changing the “decolorizing” (all carbon) filter at a rate of every 3 months or some other interval, based on time. While this sounds good and is an easy way to remember, the proper method should be changing the filter based on the number of pounds of garments that have been processed through that filter housing, not the length of time the filter has been in the machine. This is a very similar approach as that of changing your oil filter in your automobile being based on miles driven, not the amount of time it has been installed in the car. This means you will need to be keeping track of the weight of the garments processed for both the dark tank/dark machine and light tank/light machine. Using this method, you will know when the time comes due to change the filters based on the actual garments processed, thus eliminating the guesswork. You should continue to monitor your solvent clarity at all times, as the pounds of garments processed between filter changes can fluctuate some, depending on the degree of loose dye you have entering your machine.
How many pounds are recommended with an All Carbon Cartridge filter?
Based on research that was done a few years ago, it was determined that one (1) pound of activated carbon would be able to effectively control dye for every 280-300 pounds of textiles cleaned (when supplemented with at least 6 gallons of distilled solvent per 100 pounds of textiles cleaned). However, with the way today’s garments are manufactured, there is more dye being released in cleaning, reducing the actual life of the carbon in a cartridge filter because of this excess dye. Also, many machines being used may be dedicated to only processing dark colored garments, causing more dye to enter and saturate the cleaning solvent. The newer generation of drycleaning machines may have smaller base tanks and provide for less dilution of those impurities causing more solvent color, as compared to the older machines being used when those carbon studies where done. Taking into consideration these things, it is possible that the life of carbon in drycleaning may be as low as 200-250 pounds of textiles per pound of carbon and that is with the 10-15 gallons of solvent being distilled with the 2-bath processes that are so commonly used. Having said that, with an All Carbon cartridge having approximately 8 pounds of carbon, I would expect the life of that cartridge to be around 1800 – 2400 pounds of garments cleaned per cartridge on the dark tank. On the light tank, because of the lack of dye being introduced to the system, filter life can be significantly greater, often as much as 5000 pounds of garments cleaned. Are you changing your All Carbon cartridge filters at the proper intervals?
The good news is, there are a few things that can help to extend the life of your All Carbon cartridges:
- Running a 2-bath program, when machine configurations allow, can help to remove a large amount of loose/fugitive dye and send it to the still, before the filtered wash, thus lengthening the life of the filter.
- Pre-testing garments for loose dye and then running those garments in a “bleeder load” (off filter and directly to the still) or wetcleaning when possible, can help to prevent large amounts of dye from being introduced into the drycleaning solvent.
- Using effective detergents to manage moisture in the drycleaning machine better and cut down on the amount of water-soluble dyes being released into solvent.
- Maintaining a solvent temperature of no more than 80F.
The length of time a Puritan All Carbon cartridge filter lasts can vary, as there are many factors that can affect the mileage you experience from your cartridges. However, changing your all carbon filters, based on the actual weight of the cleaning processed, will provide for a more consistent level in the quality of your drycleaning and will also provide you with a method to accurately measure the life of the all carbon cartridge filter, giving you the information you need to know in order to determine the time to change those cartridges.
Lastly, do not use distillation as a substitute for carbon filtration. Distillation occurs after the cleaning cycle, therefore when dye is being released during the actual wash portion of the process, only the carbon that is available can control dye transfer and help to protect garments. Only the carbon available in your cartridge, will remove dyes being released from garments during the wash cycle of the drycleaning process.