Why Bladder Accumulators? Bearings in turbo machinery require lubrication while they are running. All turbo machines are equipped with
a lube oil system to provide the necessary lubrication
at high pressure. These lubrication systems consist of
from a high flow-rate pump, a reservoir and an
accumulator. Accumulator is a very essential part in
lube oil systems, because it supplies the lube oil to the
bearings when the pump shuts down due to a powerfailure
or a pump changeover. This prevents the
bearings from costly damage and increases the bearing
life and overall reliability of the lube oil system.

Why Bladder Accumulators?

Bearings in turbo machinery require lubrication while
they are running. All turbo machines are equipped with
a lube oil system to provide the necessary lubrication
at high pressure. These lubrication systems consist of
from a high flow-rate pump, a reservoir and an
accumulator. Accumulator is a very essential part in
lube oil systems, because it supplies the lube oil to the
bearings when the pump shuts down due to a powerfailure
or a pump changeover. This prevents the
bearings from costly damage and increases the bearing
life and overall reliability of the lube oil system.

API Standard 614 Requirements to LOSA

LOSA are designed in compliance with API 614, and
in accordance with the ASME Section VIII, DIV. 1 of
the Pressure Vessel and Boiler Code. These
accumulators are constructed from a 300 series stainless
steel shell and have a nitrile bladder, which forms a
barrier between the gas and the fluid.
If the working pressure is less than 500
psi, then the design allows a screen
welded inside the flange to keep the
bladder from extruding out of the fluid
port. The screen is welded flush and
smooth with the inside of the shell so
as not to damage the bladder. If the
pressure is more than 500 psi, then a
plug and poppet design has to be
utilized. At a low pressure the bladder
material does not extrude through the
holes in the screen but at a higher
pressure the bladder will extrude
through the holes in the screen. In a
plug in poppet design a fully inflated
bladder sits against the poppet and
expanded within the shell in order to obtain a correct
pre-charge pressure reading. Any fluid remaining in
the accumulator will cause the pressure to rise, and give
an incorrect reading. This also holds true when precharging
the accumulator. For measuring the pre-charge,
or for actually pre-charging the LOSA, the system
should be shut down or the accumulator should be
isolated from the pipeline with
an isolating valve. Any fluid
remaining in the accumulator
may be drained through the
bleed port.

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