Search for constructive solutions for grain crushers to improve crushing efficiency

The article analyzes the design solutions of the grain crushing process in the following areas of improvement of the crusher design: the organization of the crushing workflow; single and multistage crushing schemes; methods of recirculation of crushed material; the design of the crusher rotor; designs of hammers, sieves and a concave. The designs of well-known grain crushers and the results of recent achievements in their improvement were analyzed. The work notes that in order to increase the efficiency of grain crushing and obtain maximum uniformity of the crushed material, it is necessary: to carry out preliminary separation of grain into fractions according to physical and mechanical properties in the crushing chamber before crushing; to use a special form of separating sieve surfaces for preliminary separation, for example, brachystochronous surfaces; to carry out grain crushing by direct impact using an ultra-fine hammer in the form of a thin metal rod or a metal string made of high-strength material; to carry out the workflow of multistage grain crushing in one working space of the crushing chamber; to remove small particles from the crushing chamber while their forming through the use of peripheral and end separating sieves and concaves. There was developed a design of a direct impact crusher with preliminary separation of grain and crushed products which is supposed to carry out a multistage crushing of grain in one working space of the crushing chamber with the removal of crushed products of a given size due to the use of a new effective method of grain separation and feeding it for crushing. All of this allows for obtaining a grain crushing module M = 1,4-2,0 mm to reduce the specific energy consumption almost in half from 8,50-7,02 kWh/t in the DMB-P finger crusher to 4,55-3,80 kWh/t in the experimental crusher.