Radiation Errors in Air Ducts Under Nonisothermal Conditions Using Thermocouples, Thermistors, and a Resistance ThermometerU.S. National Bureau of Standards, 1969 - 12 pages Studies were made to determine the radiation error in temperature measurements made with thermocouples, thermistors, and a resistance thermometer in moving air at velocities ranging from 300 to 1300 fpm when the temperature of the duct wall surrounding the air stream was from 0 to 50 deg F higher than that of the air in the center of the duct. To eliminate all but the variable under study, conduction errors were minimized to a point where they were almost nonexistent by using Chromel P-constantan thermocouple wire and by employing other techniques. Radiation effects were studied when the probe housing the three types of temperature sensors was unshielded and again when it was shielded. Under the test conditions that prevail in the testing of air conditioners and heat pumps in laboratories, it should be possible to reduce the error in temperature measurement of the moving air to about 0.2 deg F by a suitable combination of air mixers, duct insulation, radiation shields, and calibration techniques. (Author). |
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... Calibration___ 4. Method of testing .. 5. Results.- . 6. Errors in measurement_ 7. Summary and discussion . 8. References ... 12580 9 11 11 12 Radiation Errors in Air Ducts Under Nonisothermal Conditions Using Thermocouples II.
... Calibration___ 4. Method of testing .. 5. Results.- . 6. Errors in measurement_ 7. Summary and discussion . 8. References ... 12580 9 11 11 12 Radiation Errors in Air Ducts Under Nonisothermal Conditions Using Thermocouples II.
Page 1
... calibration techniques . Key words : Conduction error ; radiation error ; resistance thermometer ; temperature ... calibrations , and to false read- ings due to thermal lag of the sensors . Other smaller sources of error found in the ...
... calibration techniques . Key words : Conduction error ; radiation error ; resistance thermometer ; temperature ... calibrations , and to false read- ings due to thermal lag of the sensors . Other smaller sources of error found in the ...
Page 2
... calibration refer- ence was needed , a platinum - resistance ther- mometer was used instead of a mercury - in - glass thermometer . 2 Throughout this paper , the more substantive results are given not only in the British units now ...
... calibration refer- ence was needed , a platinum - resistance ther- mometer was used instead of a mercury - in - glass thermometer . 2 Throughout this paper , the more substantive results are given not only in the British units now ...
Page 3
... calibration to cali- bration . The tubing was insulated with sponge- rubber and with a reflective covering . The thermocouples in the probe were of No. 30 B and S gage ( 0.010 in ) Chromel P and con- stantan wires . Each junction was ...
... calibration to cali- bration . The tubing was insulated with sponge- rubber and with a reflective covering . The thermocouples in the probe were of No. 30 B and S gage ( 0.010 in ) Chromel P and con- stantan wires . Each junction was ...
Page 4
... Calibration. DUCT WALL METALLIC AIR MIXERS DIRECTION OF AIR FLOW THERMO- COUPLE FOR MEASURING TEMPERATURE OF AIR AT INLET HEATED ACCESS DOOR WITH COPPER- CONSTANTAN THERMOCOUPLES INSULATION THERMOCOUPLE ARRAY NO.1- NO . 2 NO . 3 UNHEATED ...
... Calibration. DUCT WALL METALLIC AIR MIXERS DIRECTION OF AIR FLOW THERMO- COUPLE FOR MEASURING TEMPERATURE OF AIR AT INLET HEATED ACCESS DOOR WITH COPPER- CONSTANTAN THERMOCOUPLES INSULATION THERMOCOUPLE ARRAY NO.1- NO . 2 NO . 3 UNHEATED ...
Common terms and phrases
15 cents 50 deg F access door Achenbach air mixing air velocity aspirated assembly automatic data processing Building Science Series Bureau of Standards calibration Cement and Concrete Chromel P-constantan thermocouple Concrete Properties Conditions Using Thermocouples curves deg F 28 determined Dewar flask diameter DIFFERENCE IN TEMPERATURE duct wall error in temperature experimental Faison FPM UNSHIELDED heat pumps heated section ice bath immediately upstream inlet air inner shield Institute for Applied instrument room insulated Interrelations Between Cement junction box large reference sensor mercury-in-glass thermometers minimizing conduction errors moving air National Bureau Nonisothermal Conditions OBSERVED READINGS platinum resistance thermometer Portland Cement radiation error radiation shields Reinhold Publ SENSORS dag F set of shields shielded probe shielded sensors shown in figure small reference sensor techniques temperature difference temperature measurement temperature sensors test conditions test duct test probe thermal conductivity thermistors thermo thermocouple wire types of sensors U.S. Government Printing velocity of 300
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