Notes

a) Close the globe valve (K) and open the gate valve (D), as shown in figure (4). Switch on the bench pump and open the bench supply valve to admit water to the light blue circuit. Allow water to flow for (2 to 3 min.).
b) Close the globe valve D and bleed all of the trapped air into the top of the manometers tubes. Check that all the manometers show zero pressure difference.
c) Open the gate valve and then, by carefully opening the bled screws at the top of the mercury (U-tube), fill each limb with water. Make sure that all air bubbles have been expelled, then close the bleed screws.
d) Close the gate valve, open the globe valve, and then open fully the bench supply valve . then close the globe valve and open fully the gate valve to obtain the maximum flow rate through the light blue circuit.
e) If necessary, adjust the water levels in the manometers by pumping air into, or releasing air from the bleed valves at the tops of the manometers.
f) Record the readings of each of the manometers in the light circuit. Note the reference number of each manometer and also record the type of filling next to each pair of results. Also read the levels in the mercury (U-tube) connected between the inlet and outlet of the gate valve (D).
g) Measure the flow rate by timing the collection of water in the bench-weighing tank.
h) Measure the water temperature by holding a mercury thermometer in the flow at exit-from the outlet hose.
i) Close the gate valve to reduce the differential manometer reading by about (10%). Again read the manometers and the (U-tube), then measure the flow rate.
j) Repeat this procedure until we have about (7) sets of readings over the whole range of flow.