Хонинговальные головки

As the world’s population steadily increased (see Table 1.1), so did the demand for con­verting raw materials into valuable commodities such as medicines, minerals, and pig­ments. By the start of the 20th century, these and other commodities were being produced in volumes of tons (see Table 1.2). Along with the spectacular increases in population and […]

His berries, nuts, acorns and corn were pounded into meal; and his invention of the first pounding appliance constituted, without doubt, one of the earliest attempts to devise an instrument useful in the peaceful arts. (Bennett and Elton 1898-1904) In this chapter we discuss how stones driven by muscle power—which were first used for grains […]

In 1895, Thomas Edison was responsible for a remarkable innovation in crushing. Edison believed that high-grade deposits of iron ores in the eastern United States were running out, and he decided to develop a deposit of low-grade ore containing magnetite at a treatment rate of up to 6,000 tpd. Minimizing mining and crushing costs was […]

Many roller mills were sold from 1930 to 1950, but there was little enthusiasm for new designs because of the economic depression and World War II. The revival of industry after the war increased the demand for materials, and new mills were required with grinding chambers that had higher processing capacities. Fixed Rollers and a […]

For most of the 20th century, equipment manufacturers brought the main improvements to the technology of fine grinding. The Allis-Chalmers Company, for example, with its research programs and extensive publications, was a leading manufacturer of crushing and grinding machinery and one of the main contributors to better grinding technology. The Allis-Chalmers Company, then, is a […]

The first mills to produce fine particles at a rate of a few tons per hour were slow-speed ball mills and roller mills that were developed about 1880. By 1920, there was a strong demand for fine grinding as industry revived after World War I. By then the ball mill was so successful that for […]

We have described how the processes involved in grinding developed in unison with new forms of energy and better materials: muscle power and stone, water power and iron, steam power and steel, and electricity and alloy steels. Explosive energy is the fifth form of energy, which is used to break rocks and to prepare them […]

The 16th, 19th, and 20th centuries brought seminal changes in size-reduction technol­ogy. In each case, abundant new wealth encouraged the consumption of materials, investments in new plants, and the development of new processes and machines. This, in turn, increased the demand for size-reduction machinery with greater productivity and greater energy efficiency. In the 16th century, […]

The mortar proper rested on a stand whose height was such that its upper rim reached about to the knee of the worker, or else it and the stand were made of one piece. The pestle was made of wood about 30 to 39 inches long and narrowed down at the middle so that it […]

The incentive to build large primary gyratory crushers came in the 1920s with the devel­opment of open-pit mines for copper and iron ores. The aggregate producers’ demand for a machine that would control the size distribution and shape of pebbles at a high pro­duction rate offered the incentive to build cone crushers, which had specially […]