Хонинговальные головки

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 […]

The MB mill was designed and built in 1947 by Max Berz, formerly head of the design department at von Grueber’s company. It had three large rollers that rotated in a track­ing groove and were pressed down by a thrust ring. The rollers were not fixed by roller bearings and could move relative to each […]

With the development of ball mills, studies were made to find improved means to pro­duce finer feed for ball mills. Double-roll crushers, gyratory crushers, and cone crushers were developed for this role. Using steel rods as the grinding media in tumbling mills was found to be an efficient means to make ball mill feed and […]

As early as 1928 people started turning the hollow cylinder of the ball mill to a vertical position and started using a slow running agitator to keep the ball charge moving. The idea was to produce a uniform acceleration of the balls so that nar­rower particle size grinds results. (Netzsch 1974) In stirred mills the […]

The era of explosives started with the invention of fireworks some time in the first mil­lennium AD. It is believed that fireworks started in China, one version being that they were created by the residents’ habit of building wood fires on top of saltpeter rocks. The heat caused chemical decomposition of the saltpeter, and this […]

Because size reduction depends totally on energy used-more energy means more breakage— the link between the two merits special mention (see Table 1.3). Progress in size-reduction machines has always depended on available sources of energy. First, it was necessary to supplement human muscle power as an energy source and then to replace it entirely. Tools […]

Mortars and pestles and saddlestone mills had several problems: the exhausting motions required of the operator, the batch nature of the processes, and the unnecessary rebreak­ing of particles that were already small enough. The invention of the rotary quern, prob­ably around 600 bc (estimates of the date of its appearance vary by several hundred years), […]

Several types of single-roll mills have been built in which the solids are broken by being nipped between the rotating roll and a fixed surface. An early single-roll machine was the sledging roll crusher, which was built by Allis-Chalmers in 1911. It was a single-roll toothed crusher that was typical of a family of similar […]