Dry Cleaning Process and Wet Cleaning Process

Dry Cleaning Process and Wet Cleaning Process

What is the Dry Cleaning Process? 

Dry Cleaning process is an entirely different process, here dry cleaners wash laundry load in a chemical-based solvent and water is not at all used to wash the clothes, hence it is called a dry cleaning process. Let us find a little in-depth on how this dry cleaning process is carried out.

The use of chemicals in dry cleaning was found by accident. Earlier dry cleaners used a variety of solvents like Kerosene and Gasoline to wash the stains on the clothes and fabrics. Perchloroethylene is a chlorinated solvent used in the dry cleaning process called PERC. Carbon tetrachloride and trichloroethylene gave way to a product called Tetrachloroethylene (PERC).

PERC proved to be an effective cloth cleaning solvent, it has a property to dissolve lipophilic stains like oils, fats, greases, waxes, etc. It does not penetrate the fabric and evaporates quickly, reducing the chances of garment shrinkage. It is non-flammable and can be treated for reuse. It did a better job of cleaning, and the equipment used can be installed in retail locations with excellent quality and fast service. 

These are all the reasons why dry-cleaning is such a widely used technique in the laundry service business. Fast, convenient, clean, and attractive locations evolved to change the laundry industry that we see today.

Let's see what is the process carried out and what are the dry cleaning steps. Later, we will discuss the “Wet Cleaning” process.  

Dry Cleaning (Clean and Dry):

As the dry cleaning process is developed, so also the development in the washing machines took place as per the requirement. Initially, dry cleaning was carried out in two different machines – one is used for cleaning garments and the second is used to remove solvent fumes from garments.

Machines used during that time were known as vented machines, their drying exhaust was expelled to the atmosphere, the same as the tumble dryers do today. This not only contributed to the contamination of the atmosphere but also the PERC which can be recycled was wasted or lost to the atmosphere. Pollution Control Boards norms strictly ensure that no solvent fumes are let out into the atmosphere and all these machines must be enclosed without the vent.

Condensed and distilled solvents recovered from the dry cleaning process are reused for the next load of clothes to be dry cleaned, and part is safely disposed of with the proper treatment. Modern enclosed dry cleaning machines are incorporated with computer-controlled drying sensors, which automatically detect that all traces of PERC have been removed from the clothes.

The solvents used in the dry cleaning process tend to selectively extract the compounds from the stains. These stains otherwise dissolve in the water at a very high temperature, damaging the delicate fabrics. 

Dry Cleaning Process in Laundry Operation

Dry Cleaning machines have a stainless steel perforated drum called a basket in which the clothes are loaded, it is also called a washing and extraction chamber. This horizontal SS drum rotates in the outer shell; this shell holds the solvent whereas the inner drum holds the garments. The capacities of these machines range from 8 kgs to 50kgs and above. 

During the wash cycle, the drum is filled with one-third of the solvent at 30 degrees Celsius, as heat can damage the garments and the clothes are agitated by the rotation of this drum. This washing is done in approximately 10 to 15 minutes which is called a cycle. It depends on the type of garment and degree of soiling. In the first 3 mins solvent-soluble soils are dissolved and become loose and come out. The solvent is then removed and sent to a condenser for distillation. This solvent is further filtered through the separator to extract water, if any. Some fragile items must be enclosed in a loose mesh bag for dry cleaning. 

Dry Cleaning Extraction Process

Machines using hydrocarbon solvents require a 25-minute cycle time because of the slower rate of solvation of the solvent-soluble soils. After the wash cycle, the garments are rinsed with freshly distilled solvents. After rising, the machine begins the extraction process, removing the solvent for reuse. 

The extraction process starts by draining the solvents by accelerating the drum at 350 to 450 RPM where the maximum of the solvent is removed, by giving a solvent-free fabric by centrifugal force. When no more solvent is spun out, the machine then starts the drying process. 

During the drying process, the hot air is streamed at 60 to 65 degrees centigrade evaporating the traces of the solvent. This warm air passes through the chiller unit for condensation of the solvent and is returned to the solvent collection tank. 

To get a good solvent recovery rate and to reduce the air pollution in modern machines this chilled air is further heated and recirculated. At an early age, a large amount of PERC was vented out as it was believed to be cheap and harmless. After the drying process is complete, deodorization is done which cools the garments and removes further traces of the solvents. Here the clothes are ready to be removed from the machine for ironing and finishing. 

Wet Cleaning Process:

This process is carried out using water and using biodegradable soaps unlike dry cleaning where the solvent is used in the process. The most common of which is PERC. Environmental protection agencies believe that “Wet Cleaning” is a better process of cleaning cloths then the “Dry Cleaning” and it can be successfully used without shrinking or damaging the garments that typically require dry cleaning. 

Not only is the water that makes wet cleaning an effective method of cleaning, but well programmed computerized machines for wet cleaning, special dryers, safe detergents, and water-based spot removers are what make wet cleaning environmentally and commercially a sound method for garment treatment. 

Wet Cleaning Machine design

Wet Cleaning machines have a control that allows them to safely and efficiently be used for a wide range of fabrics in water and water-based soaps. Detergents and spot removers are biodegradable and hence safer for workers to use without any harm or side effects, environmentally friendly, yet are effective in removing the stains and spots as clean as it is done previously. Types of equipment, biodegradable detergents, and labor skills all contribute to the success of wet cleaning. 

As per the Environmental Protection Agencies, as biodegradable water-based detergents are used in wet cleaning, it is the most environmentally friendly method of garment cleaning. As hazardous chemicals are not used it does not generate hazardous waste, nor is there air pollution and also it reduces the potential of water and air pollution. All of its products are disposed of to the local drain and easily handled by the local wastewater treatment plant. 

Wet Cleaning Process

In “Wet Cleaning” Washer Extractors and Tumble Dryers are used separately. In Washer-Extractor dosing of the detergent is done as per the quality of the fabric, the temperature of the water is predefined. Cycle time varies as per the type of clothes. The only skill required is in Pre-treatment or pre Spotting. It is the skill of labor is to identify the type of water-based chemical to be used for a particular stain on a particular garment. 

After washing and rinsing the garments are taken to tumble dryer, where it is dried at a particular temperature for a particular time. It is the drying process where shrinkage takes place if the drying is not done scientifically.

Let's discuss the entire laundry Process in brief

Most people do not know what will happen to the clothes when they are dropped at one of the dry cleaners in the neighborhood. People are interested in receiving professionally cleaned and pressed clothes at a reasonable price and within a short period of time.  

  The clothes When dumped, go through the following process:  

1.      Segregation: Once the garments come to the dry cleaners, it     

is separated as per the stains and the treatment required on

the clothes.            

2.      Tagging: Paper tags and Cloth tags are used to identify the

 clothes so that they are not mixed with other clothes. Clothes

 are examined for the tear or missing buttons so that the dry

 Cleaners might get blamed for that.  

3.      Pre-Treatment/Spotting: The stains are identified and

treated for removal to make the cleaning process easier.  

4.      Dry Cleaning: The clothes are dropped into a dry cleaning

machine and cleaned by using a solvent. 

             5.   Post Spotting: Any left out stains are checked and cleaned. 

             6.   Finishing: This Includes ironing, folding, packing, and stacking

                   of the garments.  

 In the following section, the above-mentioned points         are elaborated.  

Segregation:

When the garments are dropped at the counter of the dry cleaner, they are counted and segregated as per the stains, the receiving date and the expected delivery date is mentioned. Invoices are generated and the details of the garments are automatically entered into the computerized system.

There are different types of stains like Ink, Tomato, Wine, etc. and tear at any place of cloth, all this is mentioned on the tag and segregated.  

Tagging:

After segregation proper tagging is done on the cloth, generally color tags are used to identify the exact problem with the garment. Different dry cleaners have a different practice of tagging. Currently, tagging machines are available and thermopatch tags are generated for tagging. These tags are applied to the garments and are washed, nothing happens to this tag, they remain intact. Tagging is the main and important section of the laundry service business. If tagging is improperly done sometimes, it becomes very difficult to identify the garments and the garments are lost in the process. RFID is a new technique used where a large number of similar types of linens come for washing regularly.  

Pre-Treatment/Spotting: 

Pre-treatment on the cloth is similar to what we do at home when tea or tomato sauce is spilled on our cloth, what we do is apply water and a little soap immediately locally to remove it because we know that if it persists for a long time it will become difficult to remove it later. This type of spot that remains for a long time on clothes is removed by spotting and dry cleaning.

In the spotting process, the stained part is held on the spotting table, stains, and the fabric is identified, and accordingly, the chemical is selected. Here the spotting chemical is applied and slow rubbing is done on a stained portion to remove the stains.

After pre-treatment, the garment is forwarded for dry cleaning, where the entire garment is washed in the solvent.  

Dry or Wet Cleaning: 

Post Spotting: 

Post spotting is part of the quality control process. The dry cleaning process very well removes the oil-based stains thanks to the chemical solvents. If required, the remaining stains, which have not been removed by dry cleaning, mean they need additional treatment to be carried out. Hence, water, steam, vacuum, and air pressure are used to remove any remaining traces of stains. 

Finishing: 

Finally, the clothes are checked for any repairs required like loose buttons, or making repairs. Then it is steamed to soften the garments or ironed to remove wrinkles. It is then either folded or hung in a plastic cover.  The Vacuum Finishing Table or Utility table, which we call it, is used for this process. 

Finishing:

Finally, the clothes are checked for any repairs required like loose buttons, or making repairs. Then it is steamed to soften the garments or ironed to remove wrinkles. It is then either folded or hung in a plastic cover.  Vacuum Finishing Table or Utility table that we call is used for this process. Hope you must have understood the basics of dry cleaning and wet cleaning processes.