7,3mm and external diameter 1,1cm. The bath was heated with a Bioblock Scientific polystat microprocessor controlled electrical resistance. The agitation system was composed by a propeller fitted to a Heidloph Type RZR1 mixer. The speed of the agitator could be changed with the speed reducing controller. The temperature of the bath was measured with a simple Micro-tech electronic thermometer. The inlet and outlet temperatures of the water flowing inside the coil were measured with a calibrated thermocouples K type, which were linked to Testo 922 device. 12 Figure 3: Picture of the experimental setup 13 Figure 4: Picture of the agitator blade 2.2 Experimental procedure 2.2.1 Steady state experiments The vessel was filled with a constant mass (13,92 kg) of water. The water in the bath was heated up to approximately 35 oC
RTD resistance is specified at 0°C. A typical platinum RTD with 100 W resis- tance at 0°C would have a resistance of 100.39 W at 1°C and a resistance of 119.4 W at 50°C. The tolerance of RTDs is better than thermistors. Typical tol- erance for RTDs looks like this: Platinum: .01% to .03% Copper: .2% Nickel and nickel/iron: .5% Aside from better tolerance and overall lower resistance, the interface to an RTD is similar to that for a thermistor. Thermocouples A thermocouple is made by joining two dissimilar metals. Thomas Seebeck discovered in 1821 that when such a junction is heated, it generates a tiny voltage. The amount of voltage is dependent on which two metals are joined. Three common thermocouple combinations are Iron-Constantan (Type J), Copper-Constantan (Type T), and Chromel-Alumel (Type K). The voltage produced by a thermocouple junction is very small, typically only a few millivolts
The open-circuit detection function Resolution of 1/6,000 can be used with the 1 to 5 VDC and 4 to 20 mA settings. Temperature Sensor A Temperature Sensor Unit can be connected to provide up to 6 inputs for tem- Units perature input from sensors, such as thermocouples or platinum resistance thermometers. Temperature Sensor Unit Functions Thermocouple input (CPM1A-TS001/002; 2/4 input points): K: –200° to 1,300°C (–300° to 2,300°F) 0.0° to 500.0°C (0.0° to 900.0°F) J: –100° to 850°C (–100° to 1,500°F) 0.0° to 400.0°C (0.0° to 750.0°F)
Process Lethality Calculations point of the container Heating in not homogenous in a food When a new thermal process is designed or material, even less in canned meats or meat applied for the first time to a food, F-values products, where fat, connective tissue, and are analyzed using thermocouples at various other compounds such as carbohydrates positions on the container, mainly at the cold and other additives are present, each with a point. Recently, the use of thermocouples has wide range of heat-transfer capacities. been substituted by radiotelemetry.
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