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A hammer mill is a mill whose purpose is to shred or crush aggregate material into smaller pieces by the repeated blows of small hammers. These machines have numerous industrial applications, including:
The basic principle is straightforward. A hammer mill is essentially a steel drum containing a vertical or horizontal rotating shaft or drum on which hammers are mounted. The hammers are free to swing on the ends of the cross, or fixed to the central rotor. The rotor is spun at a high speed inside the drum while material is fed into a feed hopper. The material is impacted by the hammer bars and is thereby shredded and expelled through screens in the drum of a selected size.
The hammermill can be used as a primary, secondary, or tertiary crusher.
Small grain hammermills can be operated on household current. Large hammer mills used in automobile shredders may be driven by diesel or electric motors ranging from 2000 to over 5000 horsepower (1.5 - 3.7MW).
The screenless hammer mill uses air flow to separate small particles from larger ones. It is designed to be more reliable, and is also claimed to be much cheaper and more energy efficient than regular hammermills. The design & structure of the hammermill is always determined by the end use.
Water-powered trip hammer mills were created in 488 AD by the medieval Chinese mathematician and engineer Zu Chongzhi which was inspected by Emperor Wu of Southern Qi (r. 482–493 AD). [1] [2] [3] The water-powered trip hammer mills were powered by minor hill flowing stream that was connected to a large river beneath the high banks. [4]
Types of Hammer Mill Crushers can include "up running" and "down running" hammer mills - [5]
Based on the director of the motor the hammer mills are classified into the following types:
Although the mills are classified into the above two different types their working and grinding actions of both these types of mill are almost similar. However, their construction differs in various respects. [6]
A watermill or water mill is a mill that uses hydropower. It is a structure that uses a water wheel or water turbine to drive a mechanical process such as milling (grinding), rolling, or hammering. Such processes are needed in the production of many material goods, including flour, lumber, paper, textiles, and many metal products. These watermills may comprise gristmills, sawmills, paper mills, textile mills, hammermills, trip hammering mills, rolling mills, wire drawing mills.
Millstones or mill stones are stones used in gristmills, used for triturating, crushing or, more specifically, grinding wheat or other grains. They are sometimes referred to as grindstones or grinding stones.
A crusher is a machine designed to reduce large rocks into smaller rocks, gravel, sand or rock dust.
A mill is a device, often a structure, machine or kitchen appliance, that breaks solid materials into smaller pieces by grinding, crushing, or cutting. Such comminution is an important unit operation in many processes. There are many different types of mills and many types of materials processed in them. Historically mills were powered by hand or by animals, working animal, wind (windmill) or water (watermill). In modern era, they are usually powered by electricity.
A trip hammer, also known as a tilt hammer or helve hammer, is a massive powered hammer. Traditional uses of trip hammers include pounding, decorticating and polishing of grain in agriculture. In mining, trip hammers were used for crushing metal ores into small pieces, although a stamp mill was more usual for this. In finery forges they were used for drawing out blooms made from wrought iron into more workable bar iron. They were also used for fabricating various articles of wrought iron, latten, steel and other metals.
A tree chipper or woodchipper is a machine used for reducing wood into smaller woodchips. They are often portable, being mounted on wheels on frames suitable for towing behind a truck or van. Power is generally provided by an internal combustion engine from 2 to 700 kilowatts. There are also high power chipper models mounted on trucks and powered by a separate engine. These models usually also have a hydraulic winch.
A disc mill is a type of crusher that can be used to grind, cut, shear, shred, fiberize, pulverize, granulate, crack, rub, curl, fluff, twist, hull, blend, or refine. It works in a similar manner to the ancient Buhrstone mill in that the feedstock is fed between opposing discs or plates. The discs may be grooved, serrated, or spiked.
A stamp mill is a type of mill machine that crushes material by pounding rather than grinding, either for further processing or for extraction of metallic ores. Breaking material down is a type of unit operation.
The shredding of automobiles and major household appliances is a process where a hammermill acts as a giant tree chipper by grinding the materials fed into it to fist-size pieces. The shredding of automobiles results in a mixture of ferrous metal, non-ferrous metal and shredder waste, called automotive shredder residue or automobile shredder residue (ASR). ASR consists of glass, fiber, rubber, automobile liquids, plastics and dirt. ASR is sometimes differentiated into shredder light fraction and dust. Sometimes these residual materials are called "car-fluff".
A flail mower is a type of powered garden/agricultural equipment which is used to deal with heavier grass/scrub which a normal lawn mower could not cope with. Some smaller models are self-powered, but many are PTO driven implements, which can attach to the three-point hitches found on the rear of most tractors. This type of mower is best used to provide a rough cut to long grass and even brambles in locations such as roadsides, where contact with loose debris may be possible.
A car crusher is an industrial device used to reduce the dimensions of derelict (depreciated) cars prior to transport for recycling.
An industrial shredder is a machine used to break down materials for various applications such as recycling, volume reduction, and product destruction. Industrial shredders come in many different sizes and design variations based on what particle size is needed for final shredded product.
Roller mills are mills that use cylindrical rollers, either in opposing pairs or against flat plates, to crush or grind various materials, such as grain, ore, gravel, plastic, and others. Roller grain mills are an alternative to traditional millstone arrangements in gristmills. Roller mills for rock complement other types of mills, such as ball mills and hammermills, in such industries as the mining and processing of ore and construction aggregate; cement milling; and recycling.
Comminution is the reduction of solid materials from one average particle size to a smaller average particle size, by crushing, grinding, cutting, vibrating, or other processes. In geology, it occurs naturally during faulting in the upper part of the Earth's crust. In industry, it is an important unit operation in mineral processing, ceramics, electronics, and other fields, accomplished with many types of mill. In dentistry, it is the result of mastication of food. In general medicine, it is one of the most traumatic forms of bone fracture.
Alton Scott Newell Sr. was an industrialist born in Oklahoma who invented the Newell Shredder and founded Newell Industries.
A scrap metal shredder, also sometimes referred to as a metal scrap shredder, is a machine used for reducing the size of scrap metal. Scrap metal shredders come in many different variations and sizes.
The Tiangong Kaiwu (天工開物), or The Exploitation of the Works of Nature was a Chinese encyclopedia compiled by Song Yingxing. It was published in May 1637 with funding provided by Song's patron Tu Shaokui. The Tiangong Kaiwu is an encyclopedia covering a wide range of technical issues, including the use of various gunpowder weapons. Copies of the book were very scarce in China during the Qing dynasty (1644–1911), but original copies of the book were preserved in Japan.
A grinder-mixer is a type of agricultural machine used to process livestock feed from grain. It is a portable mill that combines the mixing and grinding operations.
Feed manufacturing refers to the process of producing animal feed from raw agricultural products. Fodder produced by manufacturing is formulated to meet specific animal nutrition requirements for different species of animals at different life stages. According to the American Feed Industry Association (AFIA), there are four basic steps: