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A garbage disposal or garburator (Canadian English) or waste disposal unit (English) is an electrically-powered device installed under a kitchen sink between the sink's drain and the trap. It shreds food waste into very small pieces so that they can be passed through the plumbing without clogging. Also called a food waste disposal, they are sold in North America under brand names like "Waste King" and "In-Sink-Erator", the largest manufacturer of garbage disposals in North America. In Europe, they have some appeal and more are being installed in modern developments. There are, however, strict regulations on their installation and use in many countries. Some effluent disposal systems are not suitable for use with a kitchen waste disposal unit.

Contents 1 History 2 Types 3 Mechanism 4 External links 4.1 Videos 5 Cultural References

The garbage disposal was invented in 1927 by John W. Hammes. Mr. Hammes was an architect working in Racine, Wisconsin. After eleven years of development, his In-Sink-Erator company put his disposer on the market in 1938.

In many cities in the US the municipal sewage system had regulations prohibiting running food waste (garbage) into the system. In-Sink-Erator spent considerable effort, and was highly successful in convincing many localities to rescind these prohibitions.[1] Many localities mandated the use of disposers. [2] For many years, garbage disposals were illegal in New York City because of a perceived threat of damage to the city's sewer system. The ban was rescinded on September 11, 1997 by local law 1997/071 which amended section 24-518.1, NYC Administrative code. [3]

The device first became widely popular in upscale American kitchens of the 1970s and 1980s, yet remains very rare in European countries, due in part to greater promotion of composting kitchen waste and the pertaining regulations on sewage disposal. Concerns over environmental impact weakened its popularity, but kitchen designers and plumbers confirm the renewed appeal of the food-waste-grinding and -liquefying apparatus that lives under the sink.

There are several varieties of garbage disposal units. The most common is the continuous-feed version: the unit is turned on, usually by an electric switch on the wall, and runs until switched off. Water should always be kept running through the drain when the disposal is switched on to prevent damage to the blades. A continuous-feed model can be operated by an air switch instead of an electric switch: a small button on the counter or sink, when pressed, delivers a puff of air to a control unit connected to the garbage disposal motor, making it switch on or off. An air switch is more convenient because it can be mounted right next to or even on the sink itself, and safer as there is no electric shock hazard.

Less common is the batch-feed version, which will not run until its lid has been put in place and locked, preventing accidents that may otherwise occur if the unit is switched on while attempting carelessly to retrieve something by hand, and preventing unwanted items from falling in.

Some dishwashers are equipped with a small built-in garbage disposal unit which removes the need to prewash dishes.

A high-torque, insulated electric motor, usually rated at between ¼ and 1 horsepower for a domestic unit, spins a round, horizontal turntable above it. The turntable is surrounded by a shredder ring, which has sharp slots. The food waste sits on the turntable, and through centrifugal force is forced to its perimeter and through the shredder ring. The turntable has a number of swiveling lugs — similar to little dull blades — attached to its topside, which assist in forcing the waste through the shredder.

Some high-end domestic disposals, like their commercial counterparts, also have a blade called an undercutter which revolves under the turntable. This blade chops the ground waste even finer, and also snips any fibrous material which could cause a drain clog. Disposals with undercutters can handle fibrous waste such as artichoke leaves which cannot be successfully ground in a standard disposal.

Waste disposal units may jam, but can usually be cleared by manually turning the motor using a hex-key wrench inserted into the motor shaft from the bottom of the disposal. Very hard objects accidentally or deliberately introduced, such as metal cutlery, can damage the waste disposal unit and become damaged themselves.

Another higher-end feature is automatic reversing. By using a slightly more-complicated centrifugal starting switch, the split-phase motor rotates in the opposite direction from the previous run each time it is started. This can clear minor jams.

Some newer garbage disposal units are powered by water pressure rather than electricity, and do not pose an electrical hazard. Instead of the turntable and grind ring described above, water-powered units have an oscillating piston with blades attached to chop the waste into fine pieces. Because of this cutting action, they can handle fibrous waste and even glass (not recommended). If an item too hard to process falls in, e.g., cutlery, no harm comes to it or the unit as the blades just stop. Water-powered units take longer than electric ones for a given amount of waste, and need fairly high water pressure to function properly.

• Do-it-yourself guide to garbage disposal installation.
• Page with garbage disposal research

• Garbage disposal at YouTube. 1950s General Electric promotional film on one of the first garbage disposal units. Includes slow motion closeup footage of operation.

• A garbage disposal features prominently in an opening scene of Robert Redford's 1980 movie Ordinary People.
• A garbarge disposal is featured in 1981's The Incredible Shrinking Woman when Lily Tomlin's character "Pat Kramer" falls down the drain and is almost chopped to bits by her family.