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Q3. (A) Explain EACH of the following control terms

(i) Proportional action (2)     (ii) Integral action (2)

(B) Describe, with the aid of a sketch, a control system that may be enhanced by the inclusion of a cascade control. (6)

Q3. (A) Sketch a muff type propeller shaft coupling (5)

(b) Describe how this type of coupling is connected (5)

Q1. With reference to plate heat exchangers, explain how EACH of the following design aspects promote heat transfer:

(a) material selection;(5)

(b) flow pattern; (3)

(c) extended surface area. (2)

Q5. Describe, with the aid of a sketch, the operation of a biological sewage treatment plant (10)

Q6. With reference to a hydraulic steering gear, explain EACH of the following:

(a) The factors that may contribute to the failure of a hydraulic pipe coupling; (2)

(b) why it is of the utmost importance that in the event of a hydraulic system failure that the rudder is locked and isolation of the affected area is achieved as soon as possible; (2) (c) the problems that may occur when locking the rudder in heavy weather; (2)

(d) Why hydraulic locking is preferable to mechanical means; (2)

(e) What is meant by the single failure concept. (2)

Q6. With reference to a vapour compression refrigeration plant:

(a) explain the purpose of EACH of the following:

(i) expansion valve; (2)                  (ii) room thermostat; (2)      (iii) high pressure cut out. (2)

(b) explain why EACH of the following conditions are desirable:

(i) superheating at the compressor suction; (2)

(ii) undercooling at the condenser outlet. (2)

Q8.  With reference to fixed machinery space firefighting systems employing fresh water in a high fog or mist form, explain EACH of the following.

(a) How the fire is contained and extinguished (4)

(b) The importance of particle size and flow rate (4)

(c) State the means by which the system may be activated (2)