Two-in-One Apparatus for Measuring Temperature and Pressure in Geothermal Pipelines

Abstract

A two-in-one apparatus for measurement of temperature and pressure in geothermal pipelines has been invented and fabricated locally. The unique features of this new apparatus, in particular the improved thermowell component are the following: 1) online insertion/retraction, 2) not prone to mineral scaling, and 3) transferable anytime at any suitable tapping point along a pipeline. Such features cannot be found in other temperature-measuring devices currently used in geothermal industry. Traditional thermowells, resistance temperature detectors, and bi-metal thermometers are normally fixed and cannot be installed or retracted while a pipeline is in service. After sometime, especially in brine lines, they become coated with mineral deposits rendering erratic temperature measurements. Field applications have proven the effectiveness of this new apparatus. Its applicability has been tested in brine, two-phase and steam pipelines at various geothermal fields in the Philippines. Results showed accurate measurement of superheating and temperature drops along steam lines, and more accurate calculation of deposition potential in two-phase and brine lines, among others.