Abstract:
A process temperature estimation system includes a mounting assembly configured to mount the process fluid temperature estimation system to an external surface of a process fluid conduit. A hot end thermocouple is thermally coupled to the external surface of the process fluid conduit. A resistance temperature device (RTD) is spaced from the hot end thermocouple. Measurement circuitry is coupled to the hot end thermocouple and is configured to detect an emf of the hot end thermocouple and a resistance of the RTD that varies with temperature and provide sensor temperature information. A controller is coupled to the measurement circuitry and is configured to measure a reference temperature based on the resistance of the RTD and employ a heat transfer calculation with the reference temperature, the emf of the hot end thermocouple, and known thermal conductivity of the process fluid conduit to generate an estimated process temperature output.
Abstract:
A heat flow sensor configured to provide an indication of temperature relative to a process fluid is provided. The sensor comprises a first resistance temperature detector (RTD) element and a second RTD element spaced within a sheath from the first RTD element. The sensor also includes a set of leads comprising a first subset and a second subset, wherein the first subset is coupled to the first RTD element and the second subset is coupled to the second RTD element.
Abstract:
An explosion-proof thermal imaging system is provided. The system include an explosion-proof housing having a window that is configured to allow thermal radiation therethrough. An infrared camera is positioned within the explosion-proof housing and is disposed to receive and image thermal radiation that passes through the window. An emissivity target is disposed within a field of view of the infrared camera, but on an opposite side of the window from the infrared camera. A temperature sensor is operably coupled to the infrared camera and is configured to provide an indication of temperature proximate the emissivity target.
Abstract:
A process fluid temperature estimation system includes a mounting assembly, a sensor capsule, measurement circuitry, and a controller. The mounting assembly is configured to mount the process fluid temperature estimation system to an external surface of a process fluid conduit. The sensor capsule has an end that is configured to contact the external surface of the process fluid conduit to form an interface having a contact region and an air gap. The sensor capsule also has at least one temperature sensitive element disposed therein. The measurement circuitry is coupled to the sensor capsule and configured to detect an electrical characteristic of the at least one temperature sensitive element that varies with temperature and provide at least process fluid conduit skin temperature information. The controller is coupled to the measurement circuitry and is configured to obtain the process fluid conduit skin temperature information from the measurement circuitry and to obtain reference temperature information. The controller is configured to obtain a heat flow parameter related to the air gap of the interface and to employ a heat transfer calculation with the process fluid conduit skin temperature information, reference temperature information, and heat flow parameter to generate an estimated process fluid temperature output.
Abstract:
A process fluid flow system includes a first pipe skin sensor and a second pipe skin sensor. The first pipe skin sensor is disposed to measure an external temperature of a process fluid conduit at a first location on the process fluid conduit. The second pipe skin sensor is disposed to measure an external temperature of a process fluid conduit at a second location on the process fluid conduit. Measurement circuitry is coupled to the first and second pipe skin sensors. A controller is coupled to the measurement circuitry and is configured to identify a process fluid flow condition based on signals from the first and second pipe skin sensors and to output an indication of the process fluid flow condition.
Abstract:
A process fluid temperature calculation system includes a first temperature sensor disposed to measure an external temperature of a process fluid conduit. The process fluid temperature calculation system has a stem portion having a known thermal impedance. A second temperature sensor is spaced from the first temperature sensor by the stem portion. Measurement circuitry is coupled to the first and second temperature sensors. A microprocessor is coupled to the measurement circuitry to receive temperature information from the measurement circuitry and to provide an estimate of temperature of process fluid within the process fluid conduit using a heat flux calculation.
Abstract:
A preexisting voltage across a sensor is latched to a storage capacitor prior to any excitation current being applied to the sensor. Once the excitation current is applied, the voltage on the storage capacitor is directly subtracted from a differential voltage across the sensor. The subtraction is done before a measurement is converted to a digital value and passed to a transmitter. The subtraction is performed in hardware, and a time required to sample and hold the preexisting voltage across the storage capacitor is within a settling time used for collecting any sensor measurements.
Abstract:
A process variable transmitter is used to measure a process variable, and, in doing so, dynamically changes the resolution of the A/D converter based upon the measured value of the analog input signal. This can be done by automatically adjusting the configurable resolution gain adjustment based on the value of the analog signal being measured, by normalizing the input signal being measured so that it is centered in an optimal resolution window of the A/D converter, or by adjusting a voltage reference provided to the A/D converter.
Abstract:
A polymeric fluid sensor includes an inlet configured to receive fluid and an outlet. A polymeric tube is fluidically interposed between the inlet and the outlet and has a first sensing location with a first sidewall thickness and a second sensing location, spaced from the first sensing location, with a second sidewall thickness. A sleeve is disposed about the polymeric tube. The first sidewall thickness is less than the second sidewall thickness and a first sensing element is disposed at the first location and a second sensing element is disposed at the second location. In another example, the first and second sidewall thicknesses are the same and a fluid restriction is disposed within the polymeric tube between the first and second sensing locations.
Abstract:
A process fluid flow system includes a first pipe skin sensor and a second pipe skin sensor. The first pipe skin sensor is disposed to measure an external temperature of a process fluid conduit at a first location on the process fluid conduit. The second pipe skin sensor is disposed to measure an external temperature of a process fluid conduit at a second location on the process fluid conduit. Measurement circuitry is coupled to the first and second pipe skin sensors. A controller is coupled to the measurement circuitry and is configured to identify a process fluid flow condition based on signals from the first and second pipe skin sensors and to output an indication of the process fluid flow condition.