Small roller pelletizing machine is widely used in the fertilizer industry, due to its low price, convenient operation and maintenance, low operation cost, by the favor of small business. But small roll granulator dosing is generally placed in a hopper, raw materials, in the presence of gravity, relying on raw materials free of the sinking realization. In practice, small granulator granulation roll's biggest problem is the high rate of return (>10%), low productivity, low particle compressive strength, easily damaged, affecting product quality. Granulation process is by means of mechanical compression makes items smaller, density of the process, in this process, the narrow items entered on the roll must reach a certain density, different materials, density and output density should have a suitable proportion. According to years of practice experience and repeatedly test, caused small on roll made grain machine made grain returned material rate high and compressive strength low of main reasons, is material into on roll narrow sewing Qian of density partial small; which some raw materials wrapped has large of air, in its free sinking process in the often produced vain phenomenon, for powder raw materials, particles more small, particles between contains of air on more more, vain phenomenon on obviously, returned material rate high and products compressive strength low of problem on more serious.