The use of large primary crushing made secondary crusher plant necessary, but this department was taken care of nicely by the existing lines of standard clay secondary crusher. In commercial stone crushing plant, there was gradual increasing the number of products, but generally a sufficient demand existed for the coarser grades for ballasts and macadam roads to absorb the output. So for a time everything went along quite comfortably in this respect, and the operator concerned himself with the problem of getting out increased tonnage, selling his product as it was made, or stocking it during off-seasons for any particular grades.

Then came reinforced concrete, and with it a rapidly increasing demand for small sizes of secondary crushing stone and gravel. It is hard to say when this demand began to assume sizable proportions, but shortly after 1910 commercial plants began to feel the effects of it, and to look for a remedy. For some time, as was quite logical, the remedy consisted of installing smaller secondary crusher, generally small gyratoryes. This procedure assumed rather startling proportions in some large plants. For example, the array of crusher plant of the Brownell Improvement Co., Thornton. Ell. (Built in 1913) comprised one 48-in. primary, four N°. 7? Secondary’s and a battery of fine crushers that included four N°. 6 and twelve N°. 4 All were gyratories, although later, two sets of crushing rolls were added to augment the production small stone.Henan Hongxing Mining Machinery Co., Ltd is the professional manufacturer of complete sets of mining machinery, for example,jaw breaker,cement production line Welcome all of you to visit our official website.china mobile crusher:http://www.hx-crusher.com/mobile_crushing_station.html