The Technology Behind Kitchen Sink Garbage Disposals

Some of us have them, and most of us have at least used one. We are talking about the kitchen sink garbage disposal, of course. However, how many of us really know about the technology that makes this kitchen powerhouse actually work?

What Is a Garbage Disposal?

insinkerator septic assistBefore we get into the technology behind the garbage disposal, let’s break down what this device is. A garbage disposal, sometimes referred to as a waste disposal, is an electrically powered device that typically sits under your kitchen sink. The units itself is placed between the sink and the drain. The purpose of it is to catch the food waste that homeowners put down the drain and shred it into small enough pieces to fit down your plumbing. The general standard is for garbage disposals to cut waste into 2 millimeter pieces so that it can safely fit down your pipes. Take a look at for more information – this site notes that garbage disposal units are not very common outside of America, which could mean we are much more likely to waste food than other countries.

The Inventor: John W. Hammes

Despite the fact that garbage disposals are still considered a luxury, the very first one was invented in 1927 by John W. Hammes. After coming up with the idea for the device, he filed for a patent for technology in 1935. The world saw the very first commercial garbage disposal in 1940, developed by Hammes’ company, InSinkErator. It took some time for this device to get off the ground because there were regulations in place to prevent the disposal of food down sink pipes in the 30s and 40s. Hammes faced an uphill battle the whole way with getting cities to lift these restrictions. For the most part, however, he was extremely successful.

Garbage Disposal Technology

Now that you know a bit about the history, it is time to break down how this device works. The garbage disposal is an insulated electric motor with a high-torque. The great torque is needed to get the blades up to speed quickly to chop the waste into small pieces before they make their way through the unit and down your plumbing. Some units use induction motors, but these models usually have a low starting torque. These units also suffer from the added weight that comes with using an induction motor. As a result, they can only be used as domestic units in homes that have sinks that are big enough to support them. It is also generally recommended that these units be turned on first before the waste is added to give the blades time to get up to speed.

Although all garbage disposals have different ratings, most are rated at 250 to 800 watts, with around 1 horsepower for domestic units. Nearly all garbage disposals have a circular turntable in which impellers are installed horizontally. Most universal garbage disposals have a motor that runs at speeds around 2,800 RPM. In comparison, induction motors only run about 1,600 RPM on average. The one advantage that induction motors have over insulated motors is the fact that they are much quieter. This is due to the great torque that is put out by the insulated motors.

Once the waste goes down the garbage disposal hole, it enters the grinding chamber, where there are two metal impellers that swivel on the turntable. These are used to push the food against the grind ring. This is a process that happens repeatedly and very quickly until the food is small enough to pass down the pipe. The rubber lining at the entrance to the grinding chamber helps prevent food from being flung back out of the grinding chamber by the metal impellers. The main difference between commercial and domestic garbage disposals is that most commercial units have an additional blade installed under the turntable. The blade is great at breaking down “stringy” food that sometimes gets passed domestic units.


The technology behind the garbage disposal is pretty simple, yet it is more complex than what the average person might give it credit for. The most remarkable part is the fact that the technology has been around since the 1930s. So the next time you use a garbage disposal, remember that you are using technology that came out in the 30s and is still being used today.