Simple identification method of hydraulic oil quality

Simple identification method of hydraulic oil quality

In the absence of special testing equipment, we have summarized several methods to easily detect and identify the quality of hydraulic oil.

Moisture content

(1) Visual inspection method. If the oil is milky white and turbid, it means that the oil contains a lot of water.

(2) Combustion method. Dip a small amount of oil to be tested with clean, dry cotton yarn or tissue paper, and then ignite it with fire. If there is a "crack" popping sound or flashing phenomenon, it means that the oil contains more water.

Impurity content

(1) Direct identification. If there are obvious suspended metal particles in the oil, you will feel the presence of fine particles when you knead it with your fingers; under light, if there is a reflective flash point, it means that the hydraulic components have been severely worn; if there is a large amount of metal chips deposited on the bottom of the tank , Indicating that the main pump or motor has been severely worn.

(2) Filter paper detection. For hydraulic oil with higher viscosity, it can be diluted with pure gasoline and then filtered with clean filter paper. If a large amount of mechanical impurities (metal powder) are found on the filter paper, it indicates that the hydraulic components have been severely worn.

(3) Sound and vibration judgment. If the entire hydraulic system has large and intermittent noise and vibration, at the same time the main pump makes a "buzzing" noise, or even piston crawling phenomenon, then observe the oil tank liquid level, oil pipe outlet or transparent level gauge, you will find There are a lot of bubbles. This shows that a large amount of air has been invaded in the hydraulic oil.

(4) Heating detection. For hydraulic oil with lower viscosity, it can be directly put into a clean and dry test tube to heat up. If sediment or suspended matter is found in the oil in the test tube, it means that the oil has contained mechanical impurities.

Viscosity

(1) Test tube inversion method. Put the tested hydraulic oil and standard oil in two transparent glass test tubes with the same inner diameter and length (do not fill them too full), and plug the two test tube ports with wooden plugs. Place the two test tubes side by side, and then quickly turn them upside down at the same time. If the bubbles in the tested hydraulic oil test tube rise faster than the bubbles in the standard oil test tube, it means that the viscosity of the oil is lower than that of the standard oil; if the bubbles of the two oils rise at similar speeds, it means that their viscosity is also similar. .

(2) The glass plate tilt method. After the machine has been used for a period of time, if it is considered that the viscosity of the hydraulic oil does not meet the requirements and needs to be replaced with new oil, you can take a clean glass plate, place it horizontally, and place a drop of the tested hydraulic oil on the glass plate at the same time. Put another drop of standard hydraulic oil (new hydraulic oil of the same brand) next to it, then tilt the glass plate and observe it carefully. If the flow rate and flow distance of the tested oil are larger than that of the standard oil, it means that its viscosity is lower than that of the standard oil; on the contrary, it means that its viscosity is higher than that of the standard oil.