Copper constantan thermocouple

Not all elements of the industrial thermocouple need to be wine. For example, if a copper pipe contains a flowing fluid whose temperature is to be measured, a constantan wine attached to the pipe will form a T, or copper—constantan, thermocouple. Such arrangements ate difficult to caUbrate and requite full understanding of the possible inherent problems. For example, is the copper pipe fully annealed Homogeneous Pure, or an alloy Many ingenious solutions to specific measurement problems ate given in Reference 6. 

The liquid-liquid phase equilibria measurements under ambient pressure and temperature (288.2 K) were carried out using an apparatus of a 300 ml glass cell. The temperature of the cell was controlled by a water jacket and measured with a copper-constantan thermocouple and was estimated to be accurate within + 0.1 K. A series of liquid-liquid equilibria measurements were performed by changing the composition of the mixture. 

In order to determine the temperature profile across the melted zone of each run, a separate, identical run is carried out under the exactly same conditions. The reproduceability of the experimental runs was checked by comparing the separation results of both runs. A copper-constantan thermocouple is situated in the casted sample by inserting it during the casting, to measure the temperature of the melted zone while it is passing the thermocouple. 

The heating regimen is developed using a KAYE validator or equivalent and copper-constantan thermocouples. The determination of the load cold spot is achieved by actual experiments. A microbiological challenge test was performed to verify the sterilization conditions. Biological indicators... 

For temperature control runs it is necessary to run the conveyor in the dwell mode of operation—i.e., the carrier is transported to a fixed location, centered between the plaques in the cell, at which point a liquid nitrogen line is remotely attached to the carrier (Figure 10). The rate of nitrogen flow, hence the cooling rate, is controlled by copper-constantan thermocouples in the carriers which are connected to temperature controllers outside the irradiation cell. 

The formulation was intensively mixed for 15 s in a cylindrical vessel of 9.5 cm diameter and 10 cm height. A copper-constantan thermocouple was centered, and the signal continuously monitored. Figure 5.16 shows adiabatic temperature rise curves for different catalyst concentrations. The adiabatic temperature rise was estimated as 155°C. 

X-ray diffractometry was performed, by methods described in a companion paper (8), between 80 and 600 K at ambient pressure on thin solid wafers cut from the prepared samples. Mounted with high temperature cement on relatively massive metal backing plates, these wafers could be maintained at temperatures constant to within 3 K, as measured by either a platinum thermometer or a copper-constantan thermocouple. The... 

The dynamics of heating in the initiation region was studied with the help of a copper-constantan thermocouple mounted on the heater surface (not shown in Fig. 2). The results of the measurements are presented in Fig. 3 (the arrow indicates the instant of switching on the pulse heater). Whatever the pulse energy, no reaction burst is observed in nonirradiated samples after switching on the heater (Fig. 3, solid curve). In the preirradiated CB + Cl2 system,... 

Fig. 2.31 A simple diagram of a copper-constantan thermocouple.This illustration is from The Temperature Handbook 989 by Omega Engineering, Inc. All rights reserved. Reproduced with the permission of Omega Engineering, Inc., Stamford, CT 06907...

Problem A copper-constantan thermocouple is in an inert-gas stream at 350 K adjacent to a blackbody surface at 900 K. The heat transfer coefficient from the gas to the thermocouple is 25 W/(m2K). Estimate the temperature of the bare thermocouple, (e = 0.15 for copper-constantan.)... 

Experimental. A Parr model 1221 oxygen bomb calorimeter was modified for isothermal operation and to ensure solution of nitrogen oxides (2). The space between the water jacket and the case was filled with vermiculite (exploded mica) to improve insulation. A flexible 1000-watt heater (Cenco No. 16565-3) was bent in the form of a circle to fit just within the jacket about 1 cm. above the bottom. Heater ends were soldered through the orifices left by removing the hot and cold water valves. A copper-constantan thermocouple and a precision platinum resistance thermometer (Minco model S37-2) were calibrated by comparison with a National Bureau of Standards-calibrated Leeds and Northrup model 8164 platinum resistance thermometer. The thermometer was used to sense the temperature within the calorimeter bucket the thermocouple sensed the jacket temperature. A mercury-in-glass thermoregulator (Philadelphia Scientific Glass model CE-712) was used to control the jacket temperature. 

The conductivity cell is modified from a conventional type. It is made of borosilicate glass, which resists the attack of anhydrous chlorine and bromine trifluorides, and is equipped with two smooth platinum electrodes to minimize electrode corrosive effects. These electrodes are approximately 12x25 mm. in size, held 1.5 mm. apart with borosilicate glass spacers. The arrangement of electrodes and leads is shown in Figure 1. An internal thermocouple well leads from the top of the cell to a point near the electrodes and contains a copper constantan thermocouple. The cell constant is determined by measuring the cell resistance... 

In the second technique (to 20 atm.), the apparatus was an all-metal system similar to that used for measurements on ozone-oxygen mixtures (2). The test chamber was constructed of stainless steel. It consisted of 1-inch bar stock (I-V2 inches long), Swagelok fittings, a pressure gage, and a copper-constantan thermocouple. The system had a volume of 20.1 cc. 

Insulated Joule-Thomson cell similar to that of Fig. 2 (suitable stainless steel frits can be obtained from chromatographic parts suppliers, e.g., Upchurch Scientific part C-414) metal or nylon tees, crosses, and reducers (available from Swagelok and other manufacturers) -in. Teflon rod type T insulated copper-Constantan thermocouples with 0.010-in.-diameter wires voltmeter with 0.1-jU.V resolution (e.g., Keithley 196), null voltmeter (e.g., Hewlett Packard 419A or Keithley 155), or sensitive potentiometer (e.g., Keithley K-3). Cylinders of CO2, N2, and He with regulators and control valves 50 ft of l-in. copper coil, -in. and 1-in. polyethylene tubing 0- to 10-bar Bourdon gauge 25°C water bath. 

If the vapor pressure of liquid nitrogen is used for the temperature measurement, one allows N2 gas to condense in chamber B and the N2 pressures can be read directly on a pressure gauge. If a copper-Constantan thermocouple or a platinum resistance thermometer is used, it must be well calibrated, since accurate absolute temperatures are needed. If chamber B is not used, all further instractions concerning it may be disregarded. 

The pressure of the system was controlled to within 0.5 mm Hg for each series by a Cartesian diver manostat connected to a positive air leak, a vacuum pump, and a surge volume of 12 liters. An absolute mercury-in-glass manometer with a 0.1 mm sliding vernier was used to measure the pressure. Temperatures were monitored via two copper-constantan thermocouples one was located just above the liquid surface and the other just below it. Maximum differences of 0.4°C were detected, but an average of the two readings was reported to 0.2°C. Glacial acetic acid and acetone, both meeting ACS specifications, were used. 

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