Operating manual liquid ring vacuum pumps and compressors series TRH - TRS - TRM - TRV - SA & Systems type HYDROSYS - OILSYS
40
19 - ENGINEERING DATA
19.1 - INFLUENCE OF SERVICE LIQUID TEMPERATURE, SPECIFIC GRAVITY AND VISCOSITY ON PUMP
PERFORMANCE
The performance of liquid ring vacuum pumps is based on the use of water at 15°C as service liquid. With water at
different temperatures the pump capacity and the maximum attainable vacuum level will vary in function of the type of
pump, as illustrated by the curve sets of fig. 38 and 39.
EXAMPLE: Pressure = 60 mbar - Water temperature = 24°C - Pump series TRH - Capacity (15°C water) = 120 m
3
/h
From curves of fig. 39 we find the correcting factor of 0,80, therefore the actual capacity for the pump at
the given conditions will be: 120 x 0,80 = 96 m
3
/h.
The maximum suction pressure before incurring cavitation will be approximately 45 mbar.
Regarding the performance variation due to changes of specific gravity and viscosity, it can be assumed a proportional
variation in power consumption however, the changes in capacity at different pressures must be analysed case by
case. Please refer the conditions to POMPETRAVAINI when these corrections are needed.
Fig. 38
Single stage pump
(series TRM, TRS, TRV)
CAPACITY FACTOR
Fig. 39
Two stage pump
(series TRH)
CAPACITY FACTOR
LIMITE CAPACITA' DI ASPIRAZIONE - Lowest allowable suction pressure
Service water temperature
TEMPERATURA DELL'ACQUA DI ESERCIZIO
50°C
45°C
40°C
35°C
32°C
30°C
28°C
26°C
24°C
22°C
20°C
18°C
16°C
15°C
14°C
12°C
10°C
PRESSIONE ASSOLUTA - Absolute pressure
PRESSIONE ASSOLUTA - Absolute pressure
R
AP
PO
R
T
O
D
I PO
R
T
AT
A -
Temperat
ure
fac
tor
1,4
1,3
1,2
1,1
1,0
0,9
0,8
0,7
0,6
0,5
0,4
0,2
25
150
150
Torr
20
50
30
100
200
300
500
700
mbar
1000
700
500
300
70
200
100
50
40
30
0,3
0,2
0,4
0,5
0,6
0,7
0,8
0,9
1,0
0,3
1,1
0,3
LIMITE CAPACITA' DI ASPIRAZIONE - Lowest allowable suction pressure
PRESSIONE ASSOLUTA - Absolute pressure
PRESSIONE ASSOLUTA - Absolute pressure
R
A
P
P
O
R
T
O
D
I
P
O
R
T
A
T
A
- T
e
mpe
ratu
re f
a
cto
r
1,4
1,3
1,2
1,1
1,0
0,9
0,8
0,7
0,6
0,5
0,4
0,2
25
150
150
Torr
20
50
30
100
200
300
500
700
mbar
1000
700
500
300
70
200
100
50
40
30
0,2
0,4
0,5
0,6
0,7
0,8
0,9
1,0
0,3
32°C
LIMITE CAPACITA' DI ASPIRAZIONE - Lowest allowable suction pressure
Service water temperature
TEMPERATURA DELL'ACQUA DI ESERCIZIO
50°C
45°C
40°C
35°C
30°C
28°C
26°C
24°C
22°C
20°C
18°C
16°C
15°C
14°C
12°C
10°C
MAXIMUM OPERATING PRESSURE
SERVICE LIQUID TEMPERATURE
ABSOLUTE PRESSURE
ABSOLUTE PRESSURE
MAXIMUM OPERATING PRESSURE
SERVICE LIQUID TEMPERATURE
ABSOLUTE PRESSURE
ABSOLUTE PRESSURE