The four competitors in refrigeration at World Skills South Africa in Durban were certainly a‘ national team’ in the true sense, as they came from across the country: Tyrone Bunce( Standard Refrigeration, Durban), David le Grange( Airvent, Brackenfell, Cape Town), Valentim Valente( Penguin Refrigeration, Vryburg), and Lionald Wooldridge( Penguin Refrigeration).( We’ ll tell you more about the competition in the next edition.)
To qualify for the national competition, the four young artisans( under the age of 22 years) scored top marks in a timed theoretical test that was followed by a two-day practical test, all done under the watchful eyes of three judges. Those who have never been directly involved in the skills competition, often ask as to the level of theory that is tested.
As an example, a few questions are quoted from the 35 questions in Test 1, which totalled 200 points:
• What does the term‘ cold chain’ mean?
• Explain the term‘ convection’.
• What is latent heat?( Give one example.)
• What is subcooling?
• Draw a sketch of a three-phase motor connected in‘ star’. Name the contacts.
• A compressor fails to start, hums and trips overload. Give four possible reasons.
• What is ODP or( ODS)?
• Why do we need superheat?
|
• What is meant by the‘ boiling point’ of a refrigerant?
• How does air in the plant affect the plant?
The 30 questions in Test 2( for a total of 60 points) ask for a selection between two answers, for example:
1. What is an agitator? a. A device for mixing liquids. b. Device used to cause motion in a confined fluid.
2. What is ammonia? a. Chemical combination of nitrogen and hydrogen( NH3). Ammonia refrigerant is identified as R119. b. Chemical combination of nitrogen and hydrogen( NH3). Ammonia refrigerant is identified as R717.
3. What is check valve?
a. Valve assembly that permits flow of fluid in one direction only. b. Valve assembly that permits flow of fluid in two directions.
4. What is‘ design pressure’? a. Highest pressure expected during operation. Sometimes used as the calculated operating pressure plus an allowance for safety. b. Highest pressure expected during operation. Sometimes used as the calculated operating pressure minus an allowance for safety.
|
5. What is a flooded evaporator? a. An evaporator that contains too much liquid and needs to be drained of some liquid. b. An evaporator containing liquid refrigerant at all times.
6. What is operating pressure? a. Actual pressure at which the system works under normal conditions. The pressure can only be positive. b. Actual pressure at which the system works under normal conditions. The pressure may be positive or negative.
7. What is a relief valve? a. Safety device on a sealed system. It opens to release fluids before a dangerous pressure is reached. b. Relief valve on a sealed system that closes to stop pressure build-up.
Two hours were allowed for the completion of both tests.
Only those that scored well in the theory test entered the practical test, where they were required to install and commission a small refrigeration system with copper coils, a hermetic compressor, and hot gas defrost. Pipe bending, the use of hand tools, pressure testing, evacuation, and safe work procedures were all checked by the three judges during the allotted time of ten hours, spread over two days.
Skills competitions are competitions with a difference. They test and develop
|
the vocational skills of those working within the industry, and they are an excellent way to raise skill levels. Each competition is specifically designed to test technical skills and workplace safety as well as life skills and the ability to complete projects to a high standard within a specific timeframe. The hallmark of a good competition is that it tests skills that the youth needs to succeed in their chosen vocational career. Skills competitions bring proven benefits to a variety of groups of people, including individuals, employers, and training providers.
Competitors benefit from the experience of working under pressure and they observe excellence in action.
The competition showcases the industry and encourages new recruits. It offers access to a network of other professionals for exchanging good practice, principles, and information, and it provides added value to national standards.
World Skills South Africa is the premier skills and growth development agency in southern Africa, promoting equity through self-advancement and training. The aim is to establish international skill standards that are benchmarked through the efforts of South Africans. Employers, training providers, and industry stakeholders are called upon to support World Skills South Africa in its endeavours to develop a culture of respect towards those individuals and skills that create a better country for us all. CLA
|