Хонинговальные головки

Over the centuries, great technical achievements led to the machines of today, which can grind solid particles at the rate of tens of thousands of tons per day. The evolution of machines from devices driven by one person to immense machines with capacities of many hundred tons per hour driven by motors larger than 20,000 […]

Querns for Grinding Ores Ore breakage in Greek and Roman times was mainly by human muscle power, although cattle mills were introduced about 200 bc. The usual procedure was for rocks to be bro­ken with hammers, large pebbles to be broken in mortars and pestles up to 1.5 m deep and 4 m in diameter, […]

Secondary crushers were not used until the large open-side settings in the huge primary crushers built early in the 20th century made them necessary. The first secondary crush­ers were scaled-down standard gyratory crushers, but they had a tendency to “choke” and their productivity was low, making them inefficient for fine crushing. The growing popularity of […]

In 1848, William Easby was granted a patent for a method of converting fine coal into solid lumps. In his application, Easby made only one claim: “The formation of small par­ticles of any variety of coal into solid lumps by pressure.” In an equally brief description of the process, he mentions, “The utility and advantage […]

Starting in the late 19th century, particularly for grinding in the cement industry, tum­bling mills were built in which a short ball mill was attached to a tube mill to make a single mill with a division head separating it into two compartments. Large balls were charged to the coarse grinding compartment. Worn balls in […]

Medium-Speed Mills A “soft size reduction” mill named the Triumph mill was made by Alpine in 1898 for pre­paring foodstuffs, animal fodder, and chemicals. The pin mill used the same principle as the colloid mill but with a lower speed of rotation. Figure 8.5 is the front page of the 1903 sales brochure. This was […]

By this time, the Industrial Revolution was increasing the speed of social change; build­ings and civil works were proceeding apace, and breaking and moving rocks was becom­ing a big business. Tunnels, roads, and canals had to be built through rocky terrains, quartz and limestone had to be mined to meet the needs for aggregate and […]

Size reduction is not only the most ancient technology, it is also the most widespread. It is used in every country and in every industry that involves solid particles. Here are some of the more important applications of the technologies we profile in this book: ■ Breaking wheat grains to separate endosperm from bran and […]

In early human history, rocks used for buildings, monuments, or metal extraction were mined by hand using hammers, levers, and wedges made from stone, wood, or bone. FIGURE 3.14 Hammer and gad mining: (a) 15th-century woodcut (Agricola 1950) (b) 18th — century drawing by Eduard Heuchler showing mining and manual breakage. One exhausted miner is […]

Compared to the gyratory crusher, the cone crusher is characterized by its higher speed and a flat crushing chamber design, which is intended to give a high capacity and reduc­tion ratio for materials suitable for this type of processing. The aim is to retain material longer in the crushing chamber to do more work on […]