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Q1— Section header —
1.1Indicate whether the following statements are TRUE or FALSE by writing only rue' or ' alse' next to the question number (1.1.1
1.1.5\in the ANSWER BOOK.
1.1.1A c ylinder head serves as a pressure plate to support and hold the val es and valve plate in position.
1.1.2An o il pump is used mainly on big ammonia compressors running at low speeds and at low pressures.
1.1.3A s haft seal in refrigeration system is used as leak proof container which houses the complete mechanism of a compressor.
1.1.4A s tationery bellows type seal is mainly used in high speed compressors.
1.1.5
1.2State THREE advantages of stationery bellows type seal. (3\
1.3Inefficient pumping of a compressor may be due to certain points of failure. State FOUR causes that could result in an inefficient compressor. (4\
1.4.1Describe the construction of an axial flow fan, indicate direction of the airflow and indicate two uses of these fans in refrigeration system.
1.4.2Name two advantages and two disadvantages of reciprocating compressors (4\
Q2— Section header —
2.1What is the purpose of a condenser? (2\
2.2State SIX factors that should be considered when selecting an evaporator during the construction of refrigeration plant. (6\ (11041572\
2.3Study the FIGURE of an evaporative condenser below and name the numbered
2.3.6FIGURE (6\
2.4Briefly describe the operating principle of an evaporative condenser as in
Q2— Section header —
2.5What is the phase of the refrigerant at the inlet and outlet of the condenser? (2\ [20] (11041572\ Copyright reserved20
Q3— Section header —
3.1What is the main function of the oil separator in refrigeration system? (2\
3.2Name the following tools and state the purpose of each as used in refrigeration systems.
3.2.3(3 2\ (6\
3.3Draw a neat labelled sketch of a thermostatic pressure expansion valve. (8\
3.4Explain the TWO main functions of an expansion valve. (4\ [20]20
Q4— Section header —
4.1Types of refrigerants are indicated by the colour of the containers in which they are supplied. Name the type of refrigerant based on the following colours of the containers and state the application of each
4.1.1Light green
4.1.2Light blue
4.1.3Orange
4.1.4
4.2Define the following terms:
4.2.1Super heated vapour (3\
4.2.2Saturated vapour (3\
4.3Choose a description from COLUMN B that matches an item in COLUMN A. Write only the letter (A F\ next to the question number (4.3.1
4.3.6\in the ANSWER BOOK. COLUMN COLUMN
4.3Actuator Corrective action Control point Lag Cycle Operating differential
Q5— Section header —
5.1If a leak is found on a brazed joint, what correcti ve action should be followed? (4\
5.2Briefly explain the cause of the following malfunctions n a refrigeration plant
5.2.1The compressor fails to start (no hum\
5.2.2
5.3Draw a neat labelled sketch of a halide torch leak detector. (6\
5.4Name four way in which moisture can affect the refrigeration system. (4\ [20]20