Cork Institute of Technology
Higher Certificate in Engineering in Mechanical Engineering – Stage 1
(NFQ – Level 6)
Summer 2006
Machine Systems (Pneumatics & Hydraulics)
(Time: 2.5 Hours)
Instructions
Answer four questions.
All questions carry equal marks.
Examiners: Mr. Sean Williams
Mr. Manfred Uhlemann
Mr. J. Connolly
Mr. R. Simpson
Q1. (a) Define the term “pneumatic”.
State two applications, which utilize pneumatics.
Why was pneumatics chosen as the control medium for the applications you selected?
(5 marks)
(b) Sketch and describe the operation of two compressors from those which appear below:
(i) Single-acting, two stage, vertical, reciprocating compressor
(ii) Screw compressor
(iii) Diaphragm compressor (6marks)
(c) Distinguish between an intercooler and an aftercooler, use diagrams where
appropriate.
(5 marks)
(d) Define the term “pressure dew point”. (3 marks)
(e) Describe with the aid of sketches the operation of refrigeration dryer. (6 marks)
Q2. (a) Using table 1 and table 2 provided calculate the pressure drop between the compressor
and point “A” on the pipeline. The pipeline is shown in figure 1.
Pressure at compressor = 8 bar
Nominal pipe diameter = 40 mm
Airflow, converted to free air = 110 litre per second. (8 marks)
(b) Explain the term “F.R.L unit”. (3 marks)
(c) Describe with the aid of sketches the operation of a pressure regulator. (6 marks)
(d) Sketch a vertical receiver and label its associated components. (5
marks)
(e) Explain the term “ring main”. (3 marks)
