(a) What are the Safety Devices fitted to an Air Compressor? (4)

(b) What is the Purpose of the Scum Valve on a Boiler? (4)

(c) What is the Function of an Evaporator in a Refrigeration System? (4)

(d) Regarding the Emergency Bilge Injection Valve, what is its relevant size compared to the Main Sea Water Injection Valve? (4)