Sykes Yakka 150iC –Installation, Operation & Maintenance Manual
Page 10
AllightSykes Spare Parts & Service 24 hours: 1800 131 950
Website: www.allightsykes.com
Duty Point: A pump operating at 95l/s at 29m (Total Dynamic Head).
1) Draw a line upwards from Flow (x-axis) at 95l/s (point A).
2) Draw a line across from Total Head (y-axis) at 29m (point C)
3) Where the vertical line of 95l/s intersects the horizontal line of 29m
(point B) determines the pump rpm speed and power required at
this duty.
4) Pump Speed Curve = 2000rpm.
5) Power Requirement = 45kW to run the whole of the 2000rpm
curve.
6) To obtain NPSHR (Net Positive Suction Head Required), draw a
line across from where the vertical line of the 95l/s intersects the
NPSHR curve (point D).
7) NPSHR = 1.1m (point E).
8) Dynamic Suction Lift Available (DSLA)
DSLA = Atmosphere (m) –Velocity Head (allow 1m) –NPSHR
(m)
= 10.3m –1m –1.1m
=8.2m
To determine the actual dynamic lift of pump, it is recommended to fit a vacuum
gauge on the suction side of the pump to obtain a vacuum reading. The vacuum
gauge, for this example, should read no more than 80.4kPa (8.2m). If the vacuum
gauge reading is greater than 80.4kPa then the pump will experience cavitation.
Notes:
To ensure minimal losses to the total suction lift:
Keep suction pipes as short and straight as possible.
Eliminate all possibility of air pockets being trapped in suction pipework.
When choosing foot valves, strainers, bends etc, select those, which will
provide minimal restriction to the flow.
The diameter of the suction pipe should be equal in diameter to the pump
inlet connection.
It is recommended to fit eccentric reducer in conjunction with pipe
diameters larger than the pump inlet to avoid the possibility of air pockets
in the suction pipework.
