What should we pay attention to when measuring the interfacial tension of hydraulic oil filter
(2) because the correction factor F is used in the calculation, the size and specifications of the platinum ring and the cup are strictly required. The bottom of the cup should be straight and the diameter should not be less than 45cm. The circumference of the platinum ring is 6cm (the corrected value of the 6cm ring is much smaller than that of the 4cm ring). The ring should be kept in a circle and perpendicular to the stirrup. When measuring the surface tension of water, it is necessary to ensure that the platinum ring is not less than 5cm depth in the water. When the oil water interface tension is measured, the oil samples added to the water surface should be about 10mm thickness. If it is too thin, it will cause the platinum ring to pull out another phase (air) on the oil surface when it pulls out from the oil water interface, which will lead to errors in the experiment.
(3) to prevent the presence of impurities in the sample from affecting the test, the samples should be filtered in advance. Neutral pure distilled water was used in the test water.
(4) because of the different types and concentrations of the polar substances, the time required to migrate to the oil and water interface and to achieve a balance or stable state is also different, often taking a long time. The data obtained at this time may be much lower than those measured in the first few minutes. Therefore, an appropriate test cycle must be fixed. It is generally stipulated that the recorded data is desirable when the interface 1min is formed. This rule is applicable to both the ring method or the glass sheet method.
(5) the surface tension decreases with the increase of temperature. If the surface tension is regarded as a function of temperature, we can see that for many substances, the relationship between temperature and surface tension is linear. The experimental results show that the slope of the interfacial tension of the insulating oil decreases with the increase of temperature, though the change is slow. However, when the temperature changes, the results of the same oil sample at different temperatures often exceed the requirements of the accuracy of the test. To this end, we should take the internationally accepted results at 25C. However, according to the introduction of the literature and the measured results, the corresponding change of temperature per 10C. change is about 1mN'm. For this purpose, the general supervision test can be carried out in the range of 25 5C without constant temperature conditions. However, the trial of arbitration should be based on 25C.
- Pre：Influence of interfacial tensi 2018/5/15
- Next：The main factors that affect t 2018/5/15