Improving Measurement Uncertainty of Differential Pressures at High Line Pressures the Potential Impact on the Global Economy Environment

摘要

Typically the calibration of High Line Differential Pressure Transmitters is performed with the low side of the device open to atmosphere. Such measurements make no account of the changes that occur to the wetted parts when these devices are subjected to the high line pressures typical of their normal working environment. This practice can introduce significant measurement errors to the final outcome of a process whether it be fiscal monitoring and custody transfer of natural resources such as oil and gas, the turbine efficiency of jet engines used on aircraft and in other areas of power generation, to utilities delivering gas, water and electricity to industry and the associated industrial processes, to domestic end users and even possibly to more recent attempts at carbon sequestration and the accurate accountability for carbon credits. This paper describes a novel approach that enables the calibration of high line differential pressure transmitters at elevated line pressures. Development of this technology began in response to increased demand from industry for an accurate and easy to use differential pressure standard. This new instrument substantially reduces the calibration time by eliminating the initial cross-float required when using a twin-post piston gauge or a pressure divider. Calibrations at elevated line pressures are further simplified through active control of differential pressures, thus reducing the dependence on operator technique and experience. The line pressure range of this instrument is from 0 to 20 MPa with a differential pressure range of 0 to 200 kPa.