Bygga mobil kalibreringsbänk för flöde, tryck och temperatur : Effektivisering av kalibrering genom en mobil station

Sammanfattning

A mobile calibration station has been constructed to meet the requirements that the Department of Applied Thermodynamics and Refrigeration Technology has for measuring its components. The station has been constructed with the goal of it being mobile, modular, effective at calibrating instruments and gathering data for the department to use. Furthermore, the design of the station has been dimensioned to withstand the pressure and power within the measurement systems. To gather the required knowledge to create the station, a literature study was conducted. The study begins with general metrology and focuses on metrology within flow, pressure and temperature measurements. Furthermore, the study is concluded with focus on measurement errors when measuring and how statistics are gathered from the measured data. The construction phase for the different measurement systems is described in separate parts, such as the choice of pipe diameter, the measurement systems' form and function as well as the assembly of the system and general safety measures. The measurement instrument used is equipment that the department has previous knowledge of to implement a system for. The systems have been constructed from a safety perspective and several components and design choices have been made to lower the risks of pressurized systems, electricity and general use of the station. To validate that the calibration station is operational and fulfills the desired goals, a test run was performed. The data gathered from the test run validated that the liquid system was fully operational and fulfilled the desired goals. With the given time at 59,97 seconds, the amount of mass that flowed through the system was 11,25 kg with an average temperature of 13,47 °C. Given these values, the flow rate was calculated to 11,27 l/min and the flowmeter gave a flow rate of 13,74 l/min. The pressure calibration system could not be validated due to problems with the measuring signal. The temperature calibration was conducted with another measurement method, by using a bath of ice and submerging the thermoelements in the solution. The results from this measurement gave an offset of tens of m°C from the melting point of ice at atmospheric pressure. When all the data was acquired, a discussion about the design of the systems, probable improvements and measured data was conducted. Finally, the aim of the project and purpose was reflected on. Most of these goals were fulfilled, which is shown in the results of the station. Furthermore, the system is partially modular. For the dimensioning, the goals were also fulfilled with a few exceptions due to the choice of construction that does not affect the performance of the system. In conclusion, the purpose of the mobile calibration station is fulfilled with it being able to effectively calibrate instruments but there are still improvements that can be made to certain areas.