The main difference between a safety valve and a relief valve is: (a) Safety valves are suited for all fluids, liquids and gases whereas relief valves are designed to operate with gases only. (b) Relief valves are designed to operate with liquids only whereas safety valves can handle both liquids and gases. (c) Safety valves are designed for gases only and relief valves will only handle liquids. (d) Relief valves are designed to handle gases and safety valves are designed to handle only liquids. 2. With respect to handling hydrocarbon fluids in pipework, bonding can be defined as: (a) Joining pipework together by welding. (b) Preventing the electrostatic charge build up between two vessels when pumping hydrocarbon fluids between them by connecting them together electrically. (c) Preventing the electrostatic build-up of charge in a pipe carrying hydrocarbon fluid by connecting the pipe electrically to earth by using a copper earth strap. (d) Connecting pipework carrying hydrocarbon fluids using unions or pipe flanges to make it easier to disconnect the pipework for maintenance. 3. Saunders valves: (a) Use a diaphragm to isolate the working medium from the moving parts of the valve and are used for difficult mediums such as thick slurries, strong acids and alkalis. (b) Are used as a non-return valve for flammable fluids. (c) Are a type of multiport bidirectional control valve designed to act as a block valve. (d) Are a type of non-return valve used for difficult mediums such as strong acids and slurries. MEC1501 – Introduction to process control engineering 2 © University of Southern Queensland 4. According to the ANSI/ASME pipe code, a Shed 80, NB50 can be described as: (a) A thick wall stainless steel pipe with nominal bore size 80mm in diameter that can be operated with either high pressures or low pressures. (b) A thin walled plain carbon steel pipe with an OD of 50mm that can only be used for low pressure applications. (c) A thin wall stainless steel pipe with nominal bore size 50mm in diameter that can be operated with low pressures only. (d) A thin walled plain carbon steel pipe with nominal bore of 50mm that can be used for low or high pressure applications. 5. For piping assemblies, screwed fittings cannot be used for: (a) Galvanised piping as corrosion may develop around the threaded section (b) High flow applications as turbulence may be initiated at the threaded section (c) Sections that have to be dismantled for maintenance (d) Low pressure applications as the depth of the pipe thread reduces the pressure rating of the pipe. 6. Cold Junction Compensation can described as: (a) Adjusting the signal in a thermocouple to standardize the cold junction connection to the normalized temperature of 25°C (b) Electronically linearizing the output signal from a thermocouple. (c) Standardising the cold junction of a thermocouple by placing it in a bucket of ice. (d) Adjusting the signal in a thermocouple to standardize the cold junction connection to 0°C 7. If a constant current electrical supply is fed through the resistor of an RTD, then the voltage drop across the resistor is: (a) Directly proportional to the temperature of the resistance wire. (b) Inversely proportional to the temperature of the resistance wire. (c) Directly proportional to the change in length of the wire. (d) Inversely proportional to the change in length of the wire. 8. When measuring fluid flow, the stagnation point can be defined as: (a) The point of pressure measurement in a still body of liquid. (b) The point at which pressure is measured at the point of maximum fluid flow. (c) The static point in the middle of a pipe with it pointing directly into the direction of fluid flow. (d) The still point in the centre of a vortex created in the fluid flow.