Хонинговальные головки

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 […]

In conventional dry roller mills, air is used to transport the particles from the grinding table to the classifier inlet and through the classifier, which is built into the mill housing. The fan and air transport system can take as much power as the mill, and this is shown in the power data (see Table […]

The demand for iron, copper, and other strategic metals during World War II was enor­mous, and their resulting production depleted the available reserves of high-grade ores. After the war, large volumes of metals and cement were needed to rebuild industry and infrastructure, and a large increase in grinding capacity was required. In the United States, […]

The first mill for making particles about 1 pm in diameter was invented by Herman Plau — son at his research institute in Hamburg in 1913 with the intention of making colloidal FIGURE 8.3 Plauson-Block colloid mill (Forster and Reilly 1922) coal, although it was 1922 before it was used in industry. Within a few […]

The main cause of accidents was premature explosion. The chemical reaction that gener­ated gas and heat from the decomposition of black powder was best activated by a spark or flame but getting close enough to the charge to apply a flame and escape quickly enough to avoid injury was a distinct skill, as noted earlier. […]