Getting The Most out of A Solvent System

Everett Childers |

There are certain rules that must be followed when cleaning clothes — whether you use perc, high-flashpoint hydrocarbons, GreenEarth, water or whatever.
First, the clothes need to be classified into lights and darks, heavyweights and lightweights, fragile or special-care items, degree of soil, and of course, bleeders. Once the loads are assembled, they should be checked to see if they need any type of pretreatment.
This can often be done at the front counter or mark-in area if the plant’s customer-service reps are trained to ask about unusual spots or stains. If drycleaning is performed properly and spots and stains are marked, there will be few surprises following cleaning.
Only a few kinds of stains need any pretreatment. These include large spills, paint, lipstick, ground-in or oxidized soils, heavy grease stains, etc. Minor spots usually will be removed in a properly operated drycleaning system without any pretreatment.
Probably the most important parts of the whole process are maintaining the cleaning solvent, adding the proper detergent and picking the proper wash-cycle times. Both single-bath and two-bath systems can produce excellent cleaning results.
A short review of the basics is required here. Solvent should be distilled at a rate of at least eight gallons per 100 lbs. cleaned. Filter pressure should be low enough to put solvent through the filter and into the machine in one minute equal to the capacity of the drycleaning machine. This means that a filter pump should produce 40 gallons of solvent per minute for a 40-lb. machine; 60 gallons of solvent for a 60-lb. machine and 80 gallons of solvent for an 80-lb. machine.
The reason I say this is because pumps have been getting smaller over the past 20 years so that the maximum they can produce is about three-quarters of a gallon per minute, per pound of clothing.
When a small pump is coupled with a filter that is also inadequate in size, or the filter disks or cartridges are full of soil, there will be even less solvent getting into the wash wheel. In addition, smaller pumps can lose a lot of power when their impellers are worn or there is foreign material lodged in them.
A steady, adequate stream of solvent is necessary in the wash wheel to remove the insoluble soils that have been loosened from the garments. If these soils are not removed, they will simply redeposit onto the clothes in the wash wheel, and the garments will become dull and dingy. When spotted, the clothes will have lots of rings and circles.
Good Chemistry. Another important part of drycleaning is the proper use of detergents. We typically use two different types of detergents for solvent systems, anionic and cationic. Anionic detergents are oil-based, meaning they contain no water. Cationic detergents are usually water-based. Both do a good job of cleaning when used properly.
Anionic detergents are often used in single-bath charge systems. This means a certain amount of detergent is kept in the solvent at all times. When new solvent is added to the machine, additional detergent is also added. The charge is usually in the neighborhood of 1%, or about 100 ounces of detergent per 100 gallons of solvent. This charge allows for the proper lubrication of garments, as well as suspension properties sufficient to hold soil until it can be deposited to the filter.
As you know, there are three types of soils: insoluble soils, solvent-soluble soils and water-soluble soils. Anionic detergents will loosen and suspend insoluble soils. They will also help release oils and greases from clothing into the solvent, where these soils can build up until removed by the still.
What are water-soluble soils? They can be any type of spot, stain or odor that is carried into the fibers in a water base — including most foods, perspiration, urine and bodily fluids. These are the main reasons that people bring their clothes to the cleaner. Since anionic detergents and solvents are both “dry,” there needs to be some “wet” in the solvent, too, to remove these soils.
There are three ways to do this. The first is to simply let the clothes take in moisture or humidity from the atmosphere. The second way is to buy the detergent manufacturer’s prespotter and mix it according to directions — usually a ratio of 4:1, water to prespotter. The third way (and my favorite) is to mix the prespotter according to the label directions, adding two ounces of this mixture to the wheel or button trap for each 10 lbs. of clothes to be cleaned in the next load.
These are simple calculations: 20 lbs. of clothes need four ounces of the mixture; 30 lbs. of clothes need six ounces of the mixture; 40 lbs. of clothes need eight ounces of the mixture. Simply measure the correct amount and pour it into the wheel. Wipe the bottom of the cylinder dry with a towel, put the clothes in, and run it for a full cycle.
If you are using an oil-based drycleaning detergent, add the mixture in the same way and you will see amazing results. The results will be brighter, cleaner-smelling garments that need less spotting and finishing. And there will be no static electricity if the dry cycle isn’t too long.
If you use a water-based detergent, you probably have an injection system with a milling (off-filter) cycle of three to four minutes, with the detergent injected at the beginning of the cycle. After the milling cycle, the solvent is routed through the filters for an additional 10 to 12 minutes in perc. There is no benefit in adding a moisture solution like the one described above to a cationic system, simply because the proper amount of moisture is already in the detergent.
Not long ago, there was a race among machine manufacturers to see which could advertise the shortest cycle times — they went from 15 minutes to 12, 10, eight and six. Unfortunately, the only variable was in wash cycles. When ridiculous times like these are coupled with a small pump and clogged filters, it’s no wonder most customer complaints come from odors and redeposition of soil.
A regular load of garments needs at least a 12-minute wash cycle in a single-bath system to come clean and release the bulk of its soils. A load of silks can be cleaned in about seven minutes, due to silk’s light weight and the fact that it doesn’t absorb liquids (stains) like heavier and thicker garments do. Fragiles can be cleaned in as little as one to two minutes — not really “cleaned,” but usually sufficiently “freshened.”
Oooh, That Smell. Every one of us has heard horror stories about the odors that can arise in petroleum solvents. When a petroleum system is not maintained properly, it can develop odors that can be very difficult to get rid of. The best thing to do is simply not allow them into your drycleaning machine in the first place. How? By not putting excess amounts of moisture into the solvent through overzealous prespotting or allowing water and steam leaks in the machine.
Moisture is necessary for any solvent system to remove water-soluble soils. But machine maintenance is more strict with petroleum than it is with perc. At least once a week, all water separators should be completely drained, cleaned, and refilled with fresh water and solvent. Water attracts water, therefore it’s necessary to help the water stay in the separator. Each day, it should be drained from the bottoms of the solvent tanks. Some drycleaning machines allow you to drain water from their base tanks.
Excess standing water causes odors — bacteria in it feeds on organic matter and creates the stink. If odors develop, there are products on the market that can help kill bacteria in your machine. But steady maintenance will do the trick from the start: Do not overcharge your solvent with detergent, and distill it at the minimum rate of 8 gallons of solvent for each 100 lbs. cleaned.
Running times need to be a little longer for petroleum solvent, simply because it is lighter in weight than perc, making its mechanical action less aggressive. For full loads of regular clothes, wash cycles of about 22 minutes seem to be good, assuming solvent flow is adequate and filter pressure is not too high. With a small addition of moisture as described above, it takes at least a 22-minute wash cycle to get good water-soluble soil removal.
If you use and maintain a petroleum machine properly, you can reduce your workload and perform safer cleaning on delicate and fragile garments. To operate your equipment properly, read and understand the machine manual. For good cleaning results, follow the detergent manufacturer’s advice. If you follow these directions and clothes are still not getting clean, try other companies. After all, you must please your customers, and they look to you as the professional. Don’t let them down.

About the author

Everett Childers

Childers & Associates

Industry Consultant and Educator

Longtime industry consultant and educator Everett Childers is the author of the Master Drycleaners Notebook.


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