SK00-4167-DI-002-07
19
3.
Power Requirements
Motive energy to drive the Vacuum pump is a total value of the work of the mechanical element on
the rotary friction (mechanical work) and the work of compressing the air (compression work) that
becomes maximum when the suction pressure is between 2.7×10
4
~ 4×10
4
Pa. If the pressure went
down under 13.3 Pa, the compression work becomes smaller, then most of the motive energy shall be
spent on the mechanical work. General use of the Pump shall indicate the largest load pressure range
while the suction pressure was between 2.7×10
4
~ 4×10
4
Pa.
Operation opening the gas ballast valve would require larger motive energy at all the time as its
compression work is large even the suction pressure was small. Further, when the temperature of the
Pump site was low (in cold district or outdoor installation) starting the Pump would require larger motive
energy since the Pump oil temperature was low and its viscosity is higher. However the motive energy
value shall decrease and come stable as the oil viscosity comes lower while the Pump temperature
shall rise as it goes through operation.
Fig. 17 Power curves
Summary of Contents for PVD-180
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