Views: 209 Author: Site Editor Publish Time: 2020-10-14 Origin: Site
The areas of the large and small plungers are S2 and S1 respectively, and the forces on the plungers are F2 and F1 respectively. According to Pascal's principle, the pressure of a closed liquid is equal everywhere, that is, F2/S2=F1/S1=p; F2=F1(S2/S1). It represents the gain effect of hydraulic pressure. Like mechanical gain, the force increases, but the work does not gain. Therefore, the movement distance of the large plunger is S1/S2 times the movement distance of the small plunger. The basic principle is that the oil pump delivers the hydraulic oil to the integrated cartridge valve block, and distributes the hydraulic oil to the upper cavity or lower cavity of the cylinder through various one-way valves and overflow valves, and makes the cylinder move under the action of high-pressure oil. It is a device that uses liquid to transmit pressure. When the pressure of the liquid transfer in a closed container, it follows Pascal's law. The hydraulic transmission system of the four-column hydraulic press consists of a power mechanism, a control mechanism, an executive mechanism, an auxiliary mechanism, and a working medium. The power mechanism usually uses an oil pump as the power mechanism, which is generally a product oil pump. To meet the requirements of the movement speed of the actuator, one oil pump or multiple oil pumps are selected. Low pressure; vane pump for medium pressure; plunger pump for high pressure. Pressure processing and forming of various plastic materials, such as extrusion, bending, deep drawing of stainless steel plates, and cold forming of metal parts. It can also be used to press powder products, grinding wheels, bakelite, and resin thermosetting products.
The function of the working medium used in the hydraulic press is not only to transmit the pressure but also to ensure that the working parts of the machine are sensitive, reliable, long-lived, and less leaking.
The basic requirements of hydraulic press for working medium are:
①It has suitable fluidity and low compressibility to improve transmission efficiency;
②Can prevent corrosion;
③Has good lubrication performance;
④Easy to seal;
⑤ Stable performance, long-term work without deterioration.
The hydraulic press initially uses water as the working medium, and later it is changed to an emulsion made by adding a small amount of emulsified oil to the water to increase lubricity and reduce rust. In the late 19th century, hydraulic presses using mineral oil as the working medium appeared. The oil has good lubricity, corrosion resistance, and moderate viscosity, which is beneficial to improve the performance of the hydraulic press. In the second half of the 20th century, a new type of water-based emulsion appeared. Its emulsified form was "water in oil" instead of the original "oil in water". The outer phase of the "water-in-oil" emulsion is oil. Its lubricity and corrosion resistance is close to the oil, and it contains very little oil and is not easy to burn. However, water-based emulsions are more expensive, which limits their promotion
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