Studies On The Effects Of Hammer Mill Performance On The Grinding Results Of Normal Feedstuffs

In respect of the development of grinders in and outside China, this article summarizes the crucial points of the grinding technological development in China, then gives some procedures for it. It introduces some basics of several typical grinders (hammer mill, claws mill, roller mill, micro-grinder, and so on). The relationship between grinding properties and mechanical structures for hammer mill was mainly discussed.The working performance and economic evaluation of grinders consists of the product size, production hours, power consumption and so on. There are many factors that affect the performance of the mill, which also interact each other, Main factors are as follows: firstly, the mill properties: Hammer parameters (hammer-screen space, hammer thickness, linear velocity of hammer end), the screen plate parameters (diameter sieve, sieve size and shape, sieve arrangement, sieve-area and the perforation and cornerite of screen), ventilation, feeding process, braking room form, pulse, nesting devices, secondly, the milled feed characteristics: feed varieties and their moisture content.This article discusses mainly three topics. Firstly, the impact of ventilation on performance of the grinder, it was indicated that the productivity of grinder will be improved with the increase of ventilation, but it would be declined if the ventilation continued to be increased over one special critical point. Secondly, the impact of sieve diameter on the after-grinding granular of different raw materials was studied, it was concluded that the ratio between the diameter of sieve and the geometric mean of particle size decreased with decrease of sieve diameter. Thirdly, many tests were done on the after-grinding granular of different raw materials. The granularity of 5 raw materials after grinding with 5 different sieve was decreased sharply, which was significantly different by analysis of variances. For the same raw material, the difference of after-grinding granularity for soybean meal, wheat bran were significant (P<0.05), for corn, the difference was not significant by the sieve of 2.5mm over 1.5mm (P>0.05). For cottonseed Meal and rapeseed meal, there was no significant difference by sieve of 2.5mm over 1.5mm, and 0.6mm over 1.0mm (P>0.05).