Wash Cycles

Wash cycles usually consist of the following stages:

Break Wash - this is the most important operation. Purpose is to remove loose soil and blood. Break-wash should have a high dip (ie. water level and a low temperature which shouldn't rise above 35 degrees C). Alkaline may be used and sometimes detergent or emulsifier are added. Alkalis can start the saponification (process that produces soap) and emulsification of greasy soils. Hardness salts can be removed from some soils.

Wash - the remaining soil from the article is removed with soap or detergent, which suspend the soil in solution. This process may depend on the nature of the fabric and the disinfection requirements.

Bleach - this process is used to remove stains. It can also enhance whiteness and provides disinfection. Bleaching does not remove soils.

Rinse - this operation is designed to remove all suspended soils and residual laundry chemicals from the linen by dilution. The time of each rinse depends on the mixing criteria of the system used. Rinses normally take 2 to 3 minutes and should be repeated several consecutive times.

Thermal disinfection - this process is used on hospital linen because of the high bacterial level. Load temperature is maintained at a minimum of 65 degrees C for no less than 10 minutes. (or 71 degrees C for no less than 3 minutes). *times may vary depending on load levels.

Chemical disinfection - this process is used when high water temperature cannot be used.

The wash program controls the following:

  • timing
  • adding of water
  • heating with steam
  • adding of chemicals
  • opening and closing of the dump valve

Dosing

Most laundries have automatic chemical dosing systems. These systems pump chemicals directly into the washing machine at the correct time. It is very important that you check the correct chemicals are connected to the correct pumps. ALL chemicals must be clearly labelled too.

Dosing systems are looked after by the company that supplies the dosing pumps and chemicals. Experienced operators may have to change the drums of chemicals when they are empty.

Dosing systems are monitored by operators to ensure the right chemicals and the right amount are put into the washing machine. Sometimes Operators may need to mix chemicals and put them into the machine by hand.
If you are unsure about how to use the machine then refer to the Standard Operating Procedures.

cycles&dosing
Last modified: Wednesday, 20 June 2012, 5:50 AM