BS 6522:1984 pdf free.Methods for determination of percentage water saturation of insulating oil.
This British Standard BS 6522 describes a method of test for the determination of the percentage water saturation of insulating oil.
The method and apparatus described enables the percentage saturations of oil to be determined at temperatures up to 60 °C provided the dew-point does not exceed ambient temperature.
NOTE The titles of the publications referred to in this standard are listed on the inside back cover.
2 Principle
The method relies on the fact that if a volume of air and a volume of oil are in water equilibrium and at the same temperature then their percentage water saturations are equal. In the apparatus described, a small volume of air is circulated through a tubular semi-permeable membrane, immersed in a sample of the oil to be examined. After a short time, the air has the same percentage saturation as the oil. The dew-point of the air is measured and converted to percentage saturation; this value is then the percentage saturation of the oil sample with water at that temperature.
The oil may be heated to obtain percentage saturation at a number of temperatures.
3 Design criteria
NOTE It is important not only that the design criteria should be understood and agreed but also that there should be a common
basis when contractors are tendering.
3.1 Design of furnace linings should be based on the following objectives:
a) to achieve the required thermal design criteria including agreed thermal resistance, thermal capacity or both;
each of the component parts of the lining, both
b)to ensure that the operating temperatures for metallic and ceramic, will be acceptable in relation to the expected life;
c)to ensure similarly that the mechanical
construction is suitable for the expected duty and d)to ensure that all significant features of the construction are given approprlate attention
while at the same time not precluding the installation contractor from applying his experience and utilizing improved techniques, etc;
5 Procedure
5.1 Ensure that the desiccant in the drying chamber is dry. This may be checked by using the apparatus to circulate air through the drying chamber and past the mirror with the membrane in an empty test vessel. If the desiccant is dry the dew-point will be lower than — 30 °C.
5.2 Operate the circulating pump for 5 mm to pass air through the system and desiccant wit.h the membrane in the atmosphere: this will raise the mirror temperature a little and help avoid major upswing of temperature when the membrane is immersed in oil, should this be particularly wet.
5.3 Change the bypass valve to isolate the drying chamber. Place the test vessel containing the oil sample into position, ensuring that the membrane is completely immersed and leaving no more than 10 % space above the oil. It is necessary that the test vessel sealing is air-tight.BS 6522 pdf download.