What is the working principle of the screw oil press?

(1) Working principle of the screw oil press: The general process of extracting oil is that the rotating screw shaft pushes forward in the press chamber, causing the volume of the press chamber to shrink continuously, resulting in a continuous squeezing effect on the material. The basic process of squeezing oil is generally divided into three stages: feed pre-pressing (low pressure) stage; main squeezing (high pressure oil output) stage; cake draining (stable pressure) stage.

(2) The formation of the press chamber pressure includes:

① The reduction of the free volume of the press chamber forces the material to be compressed and form pressure. The law of axial shrinkage reflects the law of pressure change to a certain extent;

② Reduce the gap of the cake ring and increase the reaction force on the material.

(3) The characteristics of the screw oil press are that it is a continuous oil press that uses the screw shaft to rotate and push the material in the press cage, squeezing it into cakes and squeezing out oil. Compared with the "hydraulic press", its characteristics are: continuous production, large single-machine processing capacity; adaptability to a variety of oils; dynamic pressing and extrusion, friction heating, short pressing time, high oil yield; thin cakes that are easy to crush; low operating intensity. Disadvantages are relatively high energy consumption; many consumable parts, high maintenance requirements for mechanical failures; large thermal impact of oil cakes, etc.

(4) Distribution of the press chamber pressure:

① The free volume V approximates the volume of the space contained between the outer surface of each lead of the screw shaft and the inner surface of the press cage, which is called the "free volume" of the lead (single-start thread pitch), and is obtained through geometric calculation.

② The compression ratio is also called the "free volume ratio", which is the ratio of the free volumes corresponding to two adjacent leads of the screw shaft, that is, E1-2=V1/V2; the total compression ratio E is also called the "oil press or press chamber compression ratio", which is the ratio of the free volume of one lead at the feed end of the system to the free volume corresponding to one lead at the cake outlet end, that is, E=Vj/Vch. Its value is required to be greater than the actual compression ratio En of the squeezed material, and this should be the case for every lead.