The
TRIRO pump is of the positive displacement axial
flow screw type with only three moving parts - a
power rotor and two idler rotors.
|
|
|
The TRIRO flow principle
|
These
three rotors (hence the brand name TRIRO) have accurately
machined precisely intermeshing threads which enfold
the liquid being pumped and act as seals in relation
to each other and to the pump body or sleeve in which
they rotate.
The
power rotor is connected directly to the prime mover
(electric motor, diesel engine, steam turbine, etc)
and as it rotates the idlers turn due to the action
of the pumped liquid. This action is in effect, that
of a piston moving continuously in one direction,
providing a smooth uniform flow without pulsations.
The
idlers perform no work, so no gears are required
to transmit power between the screws. As radial forces
on the idlers are taken up by the surrounding cylindrical
surfaces, no other bearings are required. Axial forces
on the screwset, caused by the pressure differential
between inlet and outlet are balanced hydraulically
within the pump.
The
chamber formed between two adjacent threads and
the bore is known as a "closure" it is the
closure which contains the liquid as it moves through
the pump, as the screwset rotates the unfolding
closures in the suction chamber.
|
|
|
Hydraulic Balance
|
Create
low pressure(partial vacuums) areas into which liquid
is forced to flow by the pressure differential between
this low pressure area and the absolute pressure
on the liquid at the pump inlet. At the discharge
end, the folding closures force the liquid into the
discharge pipe against the natural resistance(known
as discharge pressure) created by the static head
and discharge pipe system frictional losses.
The
discharge or back pressure forces a certain portion
of liquid to pass back along the internal clearances
from discharge to suction. This is a characteristic
of all rotary positive displacement pumps. The very
fine working clearances of a TRIRO pump reduces this "leakage" or "slip" to
a minimum thus maximising volumetric efficency.
< Back
