Garbage disposals are machines that grind food wastes into pulp. They are mostly used in the United States of America and are rarely seen anywhere else in the world (maybe Canada). It basically consists of a motor, an impeller, a grinding ring and cutters (usually swivel type) attached to the impeller. It doesn’t use any kinds of blades, instead, when the impeller rotates the particles grind against the grinding ring which is fixed to the wall of the grinding chamber. The swivel cutters also help the grinding process. Given below is a video which you can refer to see how a garbage disposal work;
Refer the below picture to get an idea of what a garbage disposal consists of;
Garbage disposals are attached to kitchen sinks. The food that is ground goes along with the water from the sink to the waste disposal area, which is a septic tank in these cases. Water has to be run continuously during the operation of most of the disposal for its smooth working.
There are two types of garbage disposals; continuous feed and batch feed. For the continuous type you can continuously add food wastes into the grinding chamber (the food wastes are added through the sink hole). For batch feed type disposals the food wastes are added to the grinding chamber batch by batch. The continuous feed types are more popular type owing to their ease of use.
Garbage disposals vary in power. The power of a usual household garbage disposals ranges from 1/3HP to 1HP. Anything more powerful is totally unnecessary. They also vary in grinding chamber capacity and the quality and number of grinding components also vary with price. Some top end garbage disposals have a multi-grind system where the food wastes are ground through different stages whereas cheaper ones have only a single cutting stage.
How does this post help mechanical engineering students?
Garbage disposals are widely used in the USA. But it is a machine that has immense scope in cities of India and other countries. In most Indian cities, both small and large, waste disposal is a large problem. Often food wastes rot near public roads, and there is no place to dispose of them properly. Using garbage disposals one can easily grind all the food wastes into pulp and send it to the drainage. This not only reduces the amount of wastes sent to landfills but also reduces the production of Methane gas which is harmful to the ozone layer of Earth.
The working and construction of this machine is very simple and is suitable for a project. You can read more on garbage disposals here;