10
GA02330_002_06 - 01/2010 - © Oerlikon Leybold Vacuum
Description
without gas ballast
with gas ballast
at 60Hz
mbar (millibar)
torr
inches Hg
vacuum
1lb = 0.453 kg
1013
760
0
1 qt = 0.946 l
400
300
18.12
1 hp = 0.735 kW
133
100
25.98
1 inch = 25.4 mm
4
3
29.80
1 r.p.m. = 1 min -
1
0,75
29.89
0,1
0,75
29.92
1 atm (atmosphere) = 1013 mbar
1 Pa (pascal) = 0.01 mbar =10-2 mbar
1 bar = 1000 mbar
1 torr = 1.33 mbar
Different pressure units
Different pumping speed units
m
3
.h-1 l.s
-1
cfm
m
3
. h
-1
= m
3
/h 1
1
0.278
0.589
I.s
-1
= I/s
3.60
1
2.12
cfm (cubic feet per minute)
1.699
0.472
1
Example : 1m
3
.h
-1
= 0.589 cfm
Note : the nominal pumping speed of a pump at 60Hz is
20% higher than at 50Hz
Conversion factors
at 50Hz
1
10
100
1000
0,01
0,1
1
10
100
1000
Pressure (mbar)
Pumping speed (m3/h)
60 Hz
GB 7,5 m3/h
1
10
100
1000
0,01
0,1
1
10
100
1000
Pressure (mbar)
Pumpi
ng s
p
e
e
d (
m
3
/h)
50 Hz
GB 7,5 m3/h
Fig. 2
60Hz
Nominal speed
1)
cfm
200
Pumping speed
1)
cfm
171
Ultimate partial pressure without gas ballast
Torr
6.10
-2
Ultimate total pressure with gas ballast
Torrr
0.5
Water vapour tolerance with standard gas ballast standard
1)
Torr
≤
30
Motor power
hp
10.5
Rated rotational speed
rpm
1750
Weight (with oil filling)
lb
430
Oil capacity (min./max.)
qt
9/12.2
Intake connection NPT (F)
inches
NPT2
Exhaust connection NPT (F)
inches
NPT2
