Carpet cleaners are designed to deep-clean carpets and remove stains, as they pump a mixture of water and detergent into the carpet, and immediately draw the dirty water out for disposal.
The water tank is filled with clean cold tap water, and the detergent tank with a special detergent.
A pump draws the water from the tank, mixes it with the detergent and delivers it to the carpet through jets at the front of the cleaning head.
Brushes help to dislodge deeply ingrained dirt from the wet area of the carpet. Depending on the model of cleaner, these may be static or may turn. The mixture of water and dirt is sucked up from the front of the head into the recovery tank.
When the unit runs out of clean water, empty the recovery tank and refill the water tank.
When the detergent control knob is turned to off, clear water passes through the head to rinse the carpet.
Cylinder carpet cleaners work on the same principle as upright models. They can be larger than upright models and have wide set wheels to prevent them tipping over.
Cold water and detergent are mixed and poured into a storage tank.
As the carpet is cleaned, this mixture flows down a thin pipe to a wide cleaning head, and is immediately drawn back up and into the body of the unit.
Once inside the unit, the air stream enters a wider area, which causes it to slow down. The drop in speed causes the dirt and liquid droplets to fall out of the air stream and into the tank. A float blocks a hole when the tank is full, protecting the motor from water.
The motor blows the air out of vents on the top of the unit.
To empty the tank, you remove the lid and tip its contents down the drain. Some newer models have drain valves or spouts to make them easier to empty.