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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... Causes of Variation in Chemical Analyses and Physical Tests of Portland Cement . 40 cents BSS18 . Smoke and Gases Produced by Burning Aircraft Interior Materials . 35 cents BSS19 . A Study of the Variables Involved in the Saturating of ...
... Causes of Variation in Chemical Analyses and Physical Tests of Portland Cement . 40 cents BSS18 . Smoke and Gases Produced by Burning Aircraft Interior Materials . 35 cents BSS19 . A Study of the Variables Involved in the Saturating of ...
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... cause a change in results from 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 ...
... cause a change in results from 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 ...
Page 4
... caused difficulty in making the thermocouple read- ings in this region . This difficulty was overcome by the use of an integrating type digital voltmeter by which an accurate average microvolt value for each thermocouple in this region ...
... caused difficulty in making the thermocouple read- ings in this region . This difficulty was overcome by the use of an integrating type digital voltmeter by which an accurate average microvolt value for each thermocouple in this region ...
Page 6
... caused by the order in which the thermistors or the ther- mocouples were read . Analysis showed that the ... cause is not known , it is probable that there was a change in the air mixing pattern within the shield when the air ...
... caused by the order in which the thermistors or the ther- mocouples were read . Analysis showed that the ... cause is not known , it is probable that there was a change in the air mixing pattern within the shield when the air ...
Page 11
... cause of the change is not understood , but it is probable that from the spacing on figures 10 and 11 between the thermistor curves and the resistance thermometer curves , and from the con- stancy of their relative positions , that the ...
... cause of the change is not understood , but it is probable that from the spacing on figures 10 and 11 between the thermistor curves and the resistance thermometer curves , and from the con- stancy of their relative positions , that the ...
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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