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Before searching for a hammer mill for sale, it’s important to consider the material it will be working with. These machines are one of the oldest and most popular devices used for material reduction and it is now specialized in many ways as a result. Some models are best for handling rocks while others are suited for finer products like grains. The basic design of this machine, though, is standardized no matter what industry it is used in. In fact, modern versions still rely on the same physical principles of reduction that the first design did.
In 1830, a patent was issued for a device very similar to the hammer mill. Though not for sale, it was capable of breaking down rocks into smaller pieces. It consisted of a wooden box with a cylindrical drum and is considered to be the forerunner to today’s machines. Shortly after this initial patent, rotating drum machines became a viable option for shattering rocks. More than a century later, this device is still the most commonly used reduction equipment in the mining industry. Models used for shattering rocks have a couple unique design features that make them effective for this purpose. For one, they spin at much higher speeds than other models, between 700 and 1,600 revolutions a minute. A mining hammer mill for sale should also have an extremely durable screen protecting the discharge chute. The screen will receive more wear than any other part of the machine, and rocks are especially hard on a mill’s parts. Make sure that the wear plates inside the machine are also graded for long-term use, because they will be under constant assault from hard rock debris.
It wasn’t until the 1920s that the first grain hammer mill for sale became available. It was designed and built by the Gehl company, which ran the market for 30 years before other companies joined the field. Gehl also produced a mounted design that could be placed on large trucks and benefit from the added mobility. A grain grinder doesn’t need to spin as fast as a mining grinder and may come with hammers that are attached to the rotary drum or are allowed to extend and swing from it. Double or triple reduction models are available for grain grinding and come with bladed edges that slice up materials that are attached to stems. Before the material is ground up, the blades chop off the stems and separate them. A fine screen surrounding the grinding area allows grains that have been reduced enough to pass through.
However, people soon grew tired of replacing expensive, fragile screens over and over, so experts went to work developing a screenless hammer mill that could be for sale. Appropriate Technology International’s Carl Bielenberg was the first to present a design, but had trouble perfecting it. He handed over the device to MIT students, believing they could improve on it. Amy Smith, one of the students in attendance, headed the project and with her colleagues came up with a screenless grain grinder that uses air pressure instead of a screen to filter through treated product.
Smith’s design was also simple enough to be implemented in third world countries, which quickly added access to improved food sources for impoverished villages.
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