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Below the steps carried out trying to normalize the lube oil pressure GT.
first day.
We noticed that auxiliary L.O. pump was starting with 4-5 bar delivery pressure and Hi-noise and floating behavior of the L.O. pressure.
o We vent the cooler but the noise was still too high and the max reachable pump delivery pressure was 6,5 bar (required 8,5 bar)
o suspected orifice as a possible cause of low delivery pressure,
second day
1. to change the orifice size from 47 to 38 mm
2. vent the system in order to eliminate the cause of the fluctuation of the oil pressure.
3. Install 2 pressure gauges before and after the orifice in order to calculate the system flow rate
Below the result:
1.
a.After orifice change the delivery pressure increased to 7,5 to 8,5 bar,
b.The noise coming from the pump was normalized - pressure Fluctuation still present
2.
a.After we've vented the cooler, floating behavior was still present.
b.Running the pump we noticed that pressure floating behavior was getting better as long as the pump was running.
c.Assuming that air pocket were the reason of the floating phenomena, we decided to keep running.
d.The floating pressure disappeared after some time
3.
Pump started , COOLER LINE SELECTED ON TCV
a. Aux. pump discharge pressure 7.8 bar (not fluctuating)
b. Filter DP 0.25 bar
c. Orifice upstream 1.95 bar
Orifice downstream 1.8 bar
d. Lube oil bearing header pressure 1.6 bar
Pump started, 50% COOLER LINE SELECTED ON TCV
e. Aux. pump discharge pressure 7.15 bar (Not fluctuating)
f. Filter DP 0.25 bar
g. Orifice upstream 2bar
Orifice downstream 1.82 bar
h. Lube oil bearing header pressure 1.64 bar
Pump started, BYPASS LINE SELECTED ON TCV
i. Aux. pump discharge pressure 7.4 bar (Not fluctuating)
j. Filter DP 0.25 bar
k. Orifice upstream 1.95 bar
Orifice downstream 1.79 bar
l. Lube oil bearing header pressure 1.60 bar
Note:
2 lube oil tank heaters in off condition
yesterday:
o Since the max reachable header pressure was not enough,customer wanted to try to reinstate the 47 mm (this assuming that no more air pocket were present in the interconnecting piping)
o Installed the 47 mm orifice in place, the system went back to the previous status: Low pressure, Hi-noise and floating behavior of the L.O. pressure.
o We didn't succeed neither on the removal of air pocket and increase the delivery pressure, which reached max 6 bar. (due to vent line, site condition)
What could be the exact problem?
Unable to reach required header pressure and delivery pressure?
Pump getting noisy few time while adjusting the cooler by pass line?
Give some tips for this CSA.
first day.
We noticed that auxiliary L.O. pump was starting with 4-5 bar delivery pressure and Hi-noise and floating behavior of the L.O. pressure.
o We vent the cooler but the noise was still too high and the max reachable pump delivery pressure was 6,5 bar (required 8,5 bar)
o suspected orifice as a possible cause of low delivery pressure,
second day
1. to change the orifice size from 47 to 38 mm
2. vent the system in order to eliminate the cause of the fluctuation of the oil pressure.
3. Install 2 pressure gauges before and after the orifice in order to calculate the system flow rate
Below the result:
1.
a.After orifice change the delivery pressure increased to 7,5 to 8,5 bar,
b.The noise coming from the pump was normalized - pressure Fluctuation still present
2.
a.After we've vented the cooler, floating behavior was still present.
b.Running the pump we noticed that pressure floating behavior was getting better as long as the pump was running.
c.Assuming that air pocket were the reason of the floating phenomena, we decided to keep running.
d.The floating pressure disappeared after some time
3.
Pump started , COOLER LINE SELECTED ON TCV
a. Aux. pump discharge pressure 7.8 bar (not fluctuating)
b. Filter DP 0.25 bar
c. Orifice upstream 1.95 bar
Orifice downstream 1.8 bar
d. Lube oil bearing header pressure 1.6 bar
Pump started, 50% COOLER LINE SELECTED ON TCV
e. Aux. pump discharge pressure 7.15 bar (Not fluctuating)
f. Filter DP 0.25 bar
g. Orifice upstream 2bar
Orifice downstream 1.82 bar
h. Lube oil bearing header pressure 1.64 bar
Pump started, BYPASS LINE SELECTED ON TCV
i. Aux. pump discharge pressure 7.4 bar (Not fluctuating)
j. Filter DP 0.25 bar
k. Orifice upstream 1.95 bar
Orifice downstream 1.79 bar
l. Lube oil bearing header pressure 1.60 bar
Note:
2 lube oil tank heaters in off condition
yesterday:
o Since the max reachable header pressure was not enough,customer wanted to try to reinstate the 47 mm (this assuming that no more air pocket were present in the interconnecting piping)
o Installed the 47 mm orifice in place, the system went back to the previous status: Low pressure, Hi-noise and floating behavior of the L.O. pressure.
o We didn't succeed neither on the removal of air pocket and increase the delivery pressure, which reached max 6 bar. (due to vent line, site condition)
What could be the exact problem?
Unable to reach required header pressure and delivery pressure?
Pump getting noisy few time while adjusting the cooler by pass line?
Give some tips for this CSA.