Washing machines weren’t invented yesterday. The concept was born in 1767, the year in which Jacob Christian Schäffer developed a previously unheard of device: the first manual washing machine. But it wasn’t until the 20th century that his invention would be industrialized and democratized. A whole set of radical and ever-expanding innovations were developed in the last century, including the automation of appliances. Let’s take a look at how a modern washing machine works.
Types of washing machine
Household washing machines differ from industrial ones in their load capacity, the materials they’re made of, and their design.
A household machine can normally wash between 5-7kg of laundry. Industrial washing machines, such as the ones found in laundromats, are sturdier and more reliable: made from stainless steel, they can handle laundry loads of up to 30kg, including large pieces of fabric.
An industrial machine is also equipped with several wash options (variable water level, specific cycles, temperature selection, etc). The washing machines found in laundromats are special: their interface has been simplified to streamline the user experience.
The main parts of a washing machine
Every washing machine, whether household or industrial, features the following components:
The drum: a metal cylinder, perforated with small holes, into which the laundry is placed.
The outer tub: waterproof and rustproof, it houses the drum, as well as water for the wash. It is connected to the water supply.
The thermostat and water inlet control valve: the first regulates the water temperature, while the second controls the water level.
Detergent trays: several compartments that contain the detergent or soap for washing or pre-washing, as well as softener.
The electric motor: produces the drum rotation.
The pump: needed to empty the water from the tub.
The control panel: this can be digital or analogue, and it lets you set your chosen wash cycle.
Operation
How a washing machine works depends on the type of wash: normal wash (wet cleaning) or dry cleaning.
‘Normal’ washing
This wash starts with the wash cycle: clothes and other laundry are washed in water. The laundry is ‘agitated’ (mixed around) slowly at first, as the tub fills with water (a valve opens to let the water in and shuts off when the desired level is reached). Then the drum spins quickly, thanks to the motor, to soak the clothes in soapy water and remove as much dirt as possible.
A pre-wash cycle is also an option for very dirty items.
The machine then drains the dirty water from the tub using the pump. The cycle ends with the spin-dry: the drum spins at high speed to remove as much remaining water as possible before drying, either by machine or outdoors.
Dry cleaning
Dry cleaning requires use of a solvent, and no water. In general, this solvent is a chlorinated hydrocarbon, with tetrachloroethylene (perchloroethylene) being the most common.
The solvent is not removed like the water in a ‘classic’ wash is, rather, it is reused: this is known as a ‘closed circuit’.
Did you know that…? Dry cleaning was discovered by chance many years ago: in 1855, Jean-Baptiste Jolly unwittingly put turpentine and alcohol on a garment and discovered that rather than staining the clothes, the mix cleaned them. Shortly afterwards, the first dry cleaners opened in Paris.