Lube-oil pumps

Lube oil pumps are typieally heavy-duty eentrifugal or positive displaeement type with a design eapaeity that eovers the full range of antieipated operation. They ean be either direet-driven by eleetrie motors or eoupled with disk or diaphragm-type eouplings. Experieneed turboexpander manufaeturers will supply motors and eouplings that are at least 25% oversized. 

Onee ease starts to pressure up (50 psi or better), switeh No. 1 lube oil pump to manual. 

Before mining on tlie seal gas and lube oil pumps, initiate power to the eontrol panel to eonfirm tlie indieator lights are funetioning. At tliis time, there is no seal gas or lube oil pressure so tlie low lube oil alarm, low lube oil pressure shutdown, and seal gas alarm light should be on. 

The lube oil pumps are now ready to be turned on. The pump and filter bypass valves should be open to avoid pressure pulses in the filter eartridges. Strong pressure pulses may eause filter eartridges to eollapse. Typieal filter elements will withstand 35-100 psi differential. If the pumps are turned on with eaeh bypass elosed, an instantaneous pressure of approximately 150 psi will hit the filters. This is due to the setting of the relief valves. For this reason, it is important to have on hand several extra seal gas and lube oil eartridges. 

After the lube oil pumps have been running for approximaely 15 min, elose the pump and filter bypass and slowly pressurize the system to establish normal lube oil pressure. The alarm and shutdown lights should turn off by pushing the reset button on the annuneiator panel. 

If left on turning gear, it will continue until the turbine exhaust temperature decreases to 150 °F (66 °C), and a suitable amount of time (up to 60hrs) has elapsed. At this point, the turning gear and auxiliary lube oil pump will stop and the shutdown sequence is complete. On recognition of a shutdown condition, various contact status and analog values are saved (frozen) for display, if desired. 

Emergency loads Loads that are only applied on loss of normal supplies. These are usually supplied only for a fixed period of time (e.g. turbine emergency mndown lube oil pump). 

Some motor control centres are designed to allow the motor starters to reclose upon the restoration of the main busbar voltage following a supply disturbance. This is especially necessary for emergency and essential loads, e.g. cooling water pumps and lube oil pumps for engine-driven generators. If the... 

Principles of lube oil pumps. Refer to training supervisor. 

Never start the lube oil pump if the lube oil temperature is above 150°F. 

NEVER START THE LUBE OIL PUMP IF THE LUBE OIL TEMPERATURE IS ABOVE 150F. 

Lubricating oil system—cooling arrangement, oil tank, oil pumps (directly turbine shaft driven or through separate motor) with a standby pump and should auto-start in case one pump trips and safety valves at the lube oil pump discharge (should be duly tested again at purchaser s site). 

Lube oil accumulator provision should be studied before deciding the lube oil circuit. Also, the LO tank if required should be provided. Safely valves at the lube oil pump discharge should be duly calibrated by vendor and tested again at purchaser s site. 

Steam turbine trips, 350-352 trip mechanism, 350-351 emergency lube-oil pumps, 351-352 Steam turbines, 350-352, 361 trips, 350-352... 

On occasion, pumps are not directly connected to either a motor or a turbine. There is an intervening gear, which can increase the pump s speed by multiplying the driver s speed. The gear is another source of possible misalignment and vibration. I have always considered such reduction or speed increaser gears to represent poor design practice, and an unnecessary complication as they often require their own lubrication system. Most often the lube oil pump is driven indirectly by the main pump. Especially for a turbine-driven pump, this is a recipe for disaster. 

It s true that the primary lube oil pump is typically backed up by a separate, spare lube oil pump driven by an external power source. However, only too often that backup pump, which is rarely used, fails to start up automatically due to lack of routine testing, and the... 

The primary lube oil pump for the bearings was driven by the shaft of the recycle gas compressor. So it shut-down with the compressor. 

But the backup lube oil pump, which was supposed to start automatically on low lube oil pressure to the bearings, failed to start up on auto. 

The plant supervisor claimed that the destruction was due to surge. This was not true. The destruction was due to the supervisor failing to verify that his backup lube oil pump would start up on auto, on low lube oil pressure to the bearings. (See Troubleshooting Process Plant Control, Wiley, 2009 for details as to how this is done.)... 

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