4. Temperature measurement and pumps (a) A temperature sensor is required to measure the temperature of a process (data and equations are provided at the end of the exam paper). 0 A Pt 100 resistance temperature device is used. If the resistance of the device is 270 Ohms, what is the stream temperature? [3 marks) WA K Type thermocouple is used with a reference junction at temperature of 18 C. If a reading of 6.70 millivolts is obtained what is the measured temperature? [3 marks) (b) Briefly discuss the use of thermowells with temperature sensors, describing their purpose, shapes and material of construction. (4 marks) (C) Pump curves for centrifugal and positive displacement pumps are shown in Figure 4.1. 110 100 90 80 70 60 I 50 40 30 20 10 0 0 50 100 200 250 300 150 Qim'/h) -Centrifugal ----Positive displacement Figure 4.1. Pump curves for centrifugal and positive displacement pumps (0) For both pump types, explain what would happen if the pump outlet was blocked. Use numbers where appropriate. [3 marks)