Turbine lube oil system

[Emkel]

Hello newbie here, i need a mentor about steam turbine oil system

There are some pumps in turbine lubricating system
1. Main oil pump
2. AC Pump
3. DC Pump
4. Jacking Pump
5. HP Pump
6. EH Pump

I confused about HP pump, they say HP Pump is to reset the turbine, when i ask what that mean, they say the function is to help EH Pump to transefer EH oil to Hydarulic Valve. But i still dont understand what that mean.

Can you explain what HP Pump function actually? Thx before
This is the attachment

 

[byrdj]

A better drawing is needed. I can't see the image clear enough.

the red circle is near what appears to be an Eductor Pump. While I have only heard about Lube Oil systems that have such;

the eductor is a venturi jet pump that is used to move large volumes of fluid using a jet of high pressure fluid. the large volume will be supplied at a much lower pressure than the jet's pressure.

I thought the Eductor was to provide the suction head to a turbine shaft driven pump located above the oil tank.

I'll ASSUME, your Lube oil systems AC pumps only provide low pressure need for bearing lubrication. Thus the HP pump provides the high presure jet to the eductor to lift suction oil to the shaft driven pump.

I'll farther ASSUME that the shaft driven oil pumps pressure when turbine is at speed is sufficient to provide the eductor jet, thus the HP pump is only needed during roll up

Making more assumptions, the hydrualic devices associated with turbine controls could use the high pressure oil from the shaft driven oil pump as part of thier force/logic for trip/reset status. Thus the HP pump could provide that source until the unit is at speed

 

[Emkel]

Let's see

The Main Oil Pump use to supply lube oil to bearing. But, the main oil pump impeller is blended with turbine rotor. So, if Turbine speed decrease means that the main oil pump speed decrease as well. So if the main oil pump speed decreased it can't supply lube oil to bearing. So to anticipate this situation, we need AC Pump to supply the lube oil.

When the turbine speed <2800 rpm, AC pump will turn on automatically to replace main oil pump function.

DC pump is used when AC pump malfunction.

It means HP pump have nothing to do with AC pump or main oil pump. They say it has relation with EH System. And i still don't know what the relation is.

Yeah, actually i have search about this HP pump from some books or article, but still not found about HP Pump.

Are you have other assumption? Or books or something that explain this HP pump?

Previously, thanks for your answers

 

[byrdj]

the term HP lube oil Pump is not common to me. In your following post you used the term Aux oil pump, which is very familiar to me.

Other differances in terminology is that your AC oil pump, I would suspect it is reffered to as Turning Gear oil pump as It ONLY supplies oil to the bearings. As the flow demands increases with speed, the turning gear oil pump would be insuffieceint at rated speed.

to provide the extra flow for bearings at rated speed, the shaft driven oil pump is used. In the case where a shaft driven is not provided, the (larger than than turning gear oil pump) Aux oil pump is used.

as for the higher pressure oil (of the AUX oil pump) is being used to provide some type of force/logic in the tripping system, one would need to refer to the "control diagram". Usually in the logic for a mechanical over speed tripping governor, the use of a lube oil to EH oil interface mechanism is used.

refering back to the history of the evolution of turbine design, prior to the use of the seperate EH oil system, the lube oil was used to provide the force needed to position valves, thus the initial reason for the AUX oil pump.