NSC Civil Technology Civil Services Freehand sketches and scale drawings: 4.1 FIGURE 4.1 below is a drawin

Question

4.1 FIGURE 4.1 below is a drawing of a device used in cold-water systems. Study FIGURE 4.1 and answer the questions that follow.

4.1.1 Name the device in FIGURE 4.1.

4.1.2 Identify parts A, B and C.

4.1.3 Explain the function of D if part A is turned anticlokwise.

4.2 Differentiate between a pillar tap and a bibcock by referring to the way in which it is installed to/onto a sanitary fitment.

4.3 Choose a description from COLUMN B that matches an item in COLUMN A. Write only the letter A–L next to the question numbers (4.3.1 to 4.3.8) in the ANSWER BOOK, e.g. 4.3.9 M.

4.3.1 Drain-cleaning rods
4.3.2 Pipe-thread cutting machine
4.3.3 Centrifugal pump
4.3.4 Drain-cleaning machine (Jetting machine)
4.3.5 Compressed-air test apparatus
4.3.6 Water-pressure testing pump
4.3.7 Reason why drain-cleaning rods are used during an earlier use
4.3.8 A device with a manometer

4.4 Identify the tool to be used in the following scenarios:

4.4.1 Determining differences between levels and vertical heights, especially over longer distances

4.4.2 Moving sludge or liquid containing suspended matter

4.4.3 Ensuring a proper free-flowing sewer operation

4.5 The water closet is one of the household fitments that uses a lot of water. Explain ONE method that can be used to limit the usage of the water closet by using an ordinary object.

4.6 Name the device that prevents the water level inside a cistern.

4.7 FIGURE 4.7 below shows a drawing of a high-pressure geyser installation. Study the drawing and answer the questions that follow.

4.7.1 Explain the function of A.

4.7.2 A very important device that regulates the incoming water pressure was omitted at B. Name this device.

4.7.3 Identify C.

4.7.4 Is the water in pipe D HOT or COLD? Motivate your answer.

4.7.5 Identify E.

4.8 Draw the SANS approved symbols for the following hot-water systems:

4.8.1 Balancing device
4.8.2 Pressure-control valve
4.8.3 Pressure switch

4.9 Many faults can occur in hot-water systems.

4.9.1 Predict what could be the cause if water splutters through the taps.

4.9.2 Explain how this fault can be prevented.

4.10 State TWO precautionary methods to avoid an electrolytic reaction in a water system.

4.11 Galvanised sheeting is covered with a thin coating of oil to avoid rust between the sheets while stored. These sheets must be cleaned before they can be soldered.

4.11.1 Name ONE type of acid that can be used to remove the galvanised layer on these sheets before soldering.

4.11.2 Give the scientific name of the white rust/corrosion that can occur when zinc is dissolved and removed from an alloy.

4.1 FIGURE 4.1 below is a drawing of a device used in cold-water systems - NSC Civil Technology Civil Services - Question 4 - 2021 - Paper 1

Worked Solution & Example Answer:4.1 FIGURE 4.1 below is a drawing of a device used in cold-water systems - NSC Civil Technology Civil Services - Question 4 - 2021 - Paper 1

4.1.1 Name the device in FIGURE 4.1.

4.1.2 Identify parts A, B and C.

4.1.3 Explain the function of D if part A is turned anticlockwise.

4.2 Differentiate between a pillar tap and a bibcock by referring to the way in which it is installed to/onto a sanitary fitment.

4.3.1 Drain-cleaning rods

4.3.2 Pipe-thread cutting machine

4.3.3 Centrifugal pump

4.3.4 Drain-cleaning machine (Jetting machine)

4.3.5 Compressed-air test apparatus

4.3.6 Water-pressure testing pump

4.3.7 Reason why drain-cleaning rods are used during an earlier use

4.3.8 A device with a manometer