Abstract:
The calibration is defines as set of operations that establish, under specified conditions, the relationship between values of quantities indicated by a measuring instrument or measuring system, or values represented by a material measure or a reference material, and the corresponding values realized by standards.
The main objective of this research is to make a comparison of calibrate of pressure gauge by using two methods, the pressure balance method and the direct comparison method. The experimental work has been carried out in pressure calibration laboratory at Sudanese Standard & Metrology Organization, calibration of pressure gauge was studied first by pressure balance method as a primary standard method and then by the direct comparison method as a secondary standard of calibration pressure indicators. Four pressure gauges were calibrated by the two methods in which each one has been measured in various measurement points and then the error value was calculated. In the first method (pressure balance method) the pressure measured after it’s generated from the weights placed on the pressure balance and correspondingly the error was evaluated with comparison to standard value, in the second method the error of the pressure gauge measurement calculated after being measured from direct pressure generation of pressure pump. The first method was found to be more accurate than the second one and that’s owing to many parameters affecting the measurement are taken into account in calculating pressure value so that the error value is more precise, therefore the pressure balance method is the primary calibration method.
