Squeeze the principle of oil extraction, oil in the press machine in the process of press pushing , the volume of the press chamber gradually become smaller, the raw oil material get more and more resistance, the resulting squeeze force also increases, so that the oil from the raw oil material squeezed out. Oil flow out through the oil tank, after the separation of the raw oil material continue to be under pressuring and become plastic deformation to become of cake. And the cake from out of the cake mouth.
In the process of pressing, the main changes are physical changes, such as material deformation, grease separation, friction heating, water evaporation and so on. But due to temperature, moisture, microbes and other effects, but also produce some biochemical changes, such as protein denaturation, enzyme passivation and destruction, the combination of certain substances. When the raw oil material through the high pressure area, under pressure, the inner and outer surfaces are squeezed with each other, resulting in the liquid part and the gel part respectively produce two different processes, namely the oil is squeezed out from the oil tank and the raw oil material deforms to become the hard Cake.
The extrusion of the grease can be seen as the movement of the incompressible liquid in the deformed porous medium. Therefore, the average velocity of the grease flow mainly depends on the internal friction of the raw oil material fluid (viscosity) and the driving force (pressure) size. At the same time, the length of the oil flow is also an important factor affecting the stage of oil discharge rate. In general, the smaller the viscosity of the grease, the greater the pressure from the raw oil material porosity out of the faster.
During the pressing process, the viscosity of the oil is lowered due to the strong friction, which is favorable for the oil discharge. But in the high pressure area, the raw oil material deforms to a hard cake, along the spiral groove forward flow state can be regarded as laminar flow, from the material raw oil material squeezed out of oil, near the side of the tank can be successfully discharged, while the other side Grease is difficult to quickly penetrate the hard cake from the oil tank discharge, resulting in the cake with the impact of oil efficiency. The solution is to classify the squeeze, forcing the flow of the material from the laminar flow to turbulence and then squeezed again, the raw oil material after a press that is changed once the flow state, so that the raw oil material squeezed out of the oil is sufficient The opportunity is close to the sump for easy drainage.