How Liquid Filters Filter Hydraulic Oil？

Hydraulic oil plays a crucial role in hydraulic systems, and its purity is essential for the proper functioning of these systems.

Liquid filters are used to remove contaminants from hydraulic oil.

II. Types of Contaminants in Hydraulic Oil

Solid Particles: These can come from wear of mechanical parts, dirt ingress, or residues from the manufacturing process of the oil itself. For example, during the operation of hydraulic machinery, the friction between components can generate small metal particles that contaminate the oil.

Water: It can enter the hydraulic system due to environmental humidity, leaks in the system, or improper handling. Water in hydraulic oil can lead to corrosion of components and a decrease in the oil's lubricating properties. Gases: Such as air and other nitrogen oxides. Air can be introduced into the system during filling or through leaks, which may cause cavitation in the hydraulic system.

Chemical Contaminants: These are often the result of the degradation of the oil or reactions within the system. They can include acids, bases, and heavy metal ions.

III. Common Liquid Filtering Methods for Hydraulic Oil

A. Coarse Filtration and Fine Filtration Combination

In hydraulic systems, there are often two - stage filters. The first - stage is a coarse filter. Coarse filters usually use metal meshes or cotton cores. Their main function is to remove large - particle impurities. For instance, a metal mesh filter can trap relatively large solid particles like pieces of debris or large metal shavings.Ym 2-23 Bags Rocker Arm Multi-Bag Bag Filter Housing

The second - stage is a fine filter. Fine filters use more delicate filter elements such as multi - layer paper filter elements or stainless - steel filter elements. These are designed to remove smaller particles and other contaminants that the coarse filter may have missed. For example, a multi - layer paper filter can capture fine metal particles and some chemical substances.Ym 2-23 Bags Rocker Arm Multi-Bag Bag Filter Housing

B. Electromagnetic Filters

Electromagnetic filters operate based on the principle of electromagnetic force. They are effective in removing minute metal particles from the hydraulic oil.

The filter creates an electromagnetic field. When the hydraulic oil passes through the filter, the suspended metal particles in the oil are quickly attracted to the filter element by the electromagnetic force. However, it should be noted that electromagnetic filters are not capable of removing non - metallic contaminants such as water, gases, and most chemical contaminants.

C. Activated Carbon Adsorption

Activated carbon has a large specific surface area and high adsorption capacity. It is used to filter chemical contaminants in hydraulic oil.

When the hydraulic oil passes through the activated carbon filter, the harmful chemical substances in the oil, such as acids, bases, and heavy metal ions, are adsorbed onto the surface of the activated carbon. The activated carbon is usually in granular or particulate form and is placed inside the filter for adsorption filtration.

D. Microporous Membrane Filtration

Microporous membrane filtration utilizes specially - made microporous membranes to filter hydraulic oil. The pore size of the microporous membrane is usually between 0.1 - 10 microns.

This small pore size enables the membrane to effectively remove tiny particles, water, and other impurities. Microporous membrane filters typically have high filtration precision and a relatively long service life, making them widely used in high - requirement hydraulic systems.Ym 2-23 Bags Rocker Arm Multi-Bag Bag Filter Housing

IV. Steps in Filtering Hydraulic Oil with Liquid Filters

A. Preparation

Before starting the filtration process, it is necessary to check the hydraulic oil to determine if it needs to be replaced. This can be done by checking for unusual odors, changes in viscosity, or if the oil has been in use for an extended period (e.g., more than 4,000 hours).

Also, check the filter element to ensure it is in good condition and has the appropriate filtration precision. The filtration precision of the hydraulic oil filter element should not be higher than 10 µm in general, and it should be replaced regularly according to the shanghai sffiltecch Bag Filter Housing manufacturer's

B. Initial Filtration

Retract all hydraulic cylinders to their fully retracted positions.

Use the filtering device to pump the hydraulic oil from the tank into a clean oil drum. For the remaining oil at the bottom of the tank, it can be drained through the drain port and then filtered. Use the filtered oil to flush out the impurities at the bottom of the tank.

C. System Flushing

Use the filtering device to pump the oil from the oil drum back into the tank.

Run all motors at the 10th gear for at least 30 seconds and make the hydraulic cylinders complete at least one extension and retraction. This will flush out most of the oil in the cylind