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A soap dispenser is a device that, when manipulated or triggered appropriately, yields soap (usually in small, single-use quantities). It can be manually operated by means of a handle, or can be automatic. Soap dispensers are often found in public restrooms.
Manual soap dispensers
The design of a manual soap dispenser is generally determined by whether the soap comes in liquid, powder, or foam form.
William Shepphard patented liquid soap on August 22, 1865. Minnetonka Corporation introduced the first modern liquid soap and cornered the market by buying up the entire supply of the plastic pumps needed for the liquid soap dispensers.
Dispensers of powder soaps, such as borax, often take the form of a metal box with a weighted lever; when the lever is pressed, a handful of soap is released.
Manual dispensers of foam soap often consist of a large button which squeezes the foam out of a tube. Many liquid soap dispensers operate in this way as well. A few dispensers operate with a lever that pulls forward and squeezes the soap out.
99% of manual foam soap dispensers have the soap in a bladder in the dispenser in liquid form, as the pump is pressed the liquid soap is pushed through a small foaming nozzle which foams the soap.
Automatic soap dispensers
An automatic soap dispenser is specifically a hands-free dispenser of soap (both liquid soap and foaming soap), but generally can be used for other liquids such as hand sanitizers, shampoos, or hand lotions. Automatic dispensers are often battery-powered. The touch-free design dispenses the liquid when a sensor detects motion under the nozzle. The electronic components of an automatic soap dispenser allow for a timing device or signal (sound, lights, etc.) which can indicate to the user whether they have washed their hands for the correct amount of time or not.
Hands-free dispensers for water and soap/hand sanitizer have particular virtues for operating theatres and treatment rooms.
Foam soap dispensers
Foam soap dispensers have dual pumps that when used move both air and soap, injecting both together through small openings to create a lather. They can be found in both manual and automatic varieties.