Walnut kernels contain more than 60% oil, which is one of the dried fruits with higher oil content. Among the processed products, walnuts are mostly used to be processed into edible oil. Extracting walnut oil by pressing is a more mature extraction process used in modern industrial production.
Its production principle is to use external physical pressure to squeeze out the oil in the oil plant, which belongs to the mechanical processing method. The equipment used to squeeze and extract walnut oil includes screw oil press and hydraulic oil press.
Spiral Walnut Oil Press
1. Process method
When the screw oil press processes walnut oil, the walnuts are mechanically sent to the feeding device, and are continuously fed into the pressing part of the oil press under the push of the screw blades. Due to the reduction of the screw lead and the increase of the bottom diameter, the volume Reduced, resulting in a change in pressure, the pressure formed constantly squeezes the walnut.
The positive conveying characteristic of the screw shaft makes the squeezed oil flow out through the gap of the squeeze chamber, and the remaining oil residue continues to be pushed forward for pressing, and the formed oil cake is discharged from the cake outlet of the oil press, and the obtained oil is simply filtered through the filter screen and collected container.
Advantages: No chemical reagents are used in the whole process, and the raw materials are not polluted, which belongs to physical pressing.
Disadvantages: When the pressing temperature is too low, the viscosity of the oil is high and the fluidity is poor, which makes it difficult to discharge the oil, and the cake is easy to get stuck in the cake ring, so it needs to add heat from the outside.
Summary: The walnut screw oil press machine is suitable for hot pressing walnut oil.
The price of BTMA screw walnut oil press is around US$1,000 to US$4,000, mainly related to the processing capacity of the screw walnut oil press.
Hydraulic walnut oil press
1. Process method
The hydraulic walnut oil press is an oil press machine that uses hydraulic oil to pressurize the walnut through the oil pump, and a temperature control device is installed on the machine to make the walnut oil out under high pressure and high temperature. It takes about 2 to 5 hours to squeeze once. When the electric oil pump is used, a circulating oil circuit system can be formed, and several hydraulic oil presses can be operated at the same time.
Advantages: Walnuts with shells can be directly squeezed raw, the walnut oil is lighter in color, the nutrients are better preserved, the taste is better, and the quality of walnut oil produced is higher.
Disadvantages: The processing efficiency is relatively low.
Summary: The walnut hydraulic oil press machine is suitable for cold pressing walnut oil.