| Flexible Impeller Pumps |
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Flexible impeller pumps provide an efficient
solution to most marine pumping needs. The primary
advantage of a flexible impeller pump is its self-priming
capability. As the vanes of the impeller are
depressed and rebound, they create their own vacuum
drawing fluid into the pumps (see operating principle).
A dry pump can lift water up to as much as 3
meters. Thus a flexible impeller pump being used
in bilge, deck wash, or engine cooling need not
be located below the water line or manually primed.
An added feature of flexible impeller pumps is
that they can pass fairly large liquid without
clogging or damaging the pump. this reduces the
need for filtering the incoming fluid.
A common feature of all flexible impeller pumps
is that they cannot be permitted to run dry for
more than 30 seconds. Both the impeller and the
seals depend upon the water for lubrication and
will soon burn out if run dry. Wearing parts are
easily replaceable, and service kits are available
for all models.
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Operating principle
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After the blades leave the cam, the blades pop
up. The action creates a vacuum, which draws liquid
into the pump
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Each blade draws in liquid and carries it to
the outlet port
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When the blades compress, they expel the remainder
of the liquid. The flow is continuous and uniform.
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Determining Inlet and Outlet Port depending
on Rotating Direction
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When the rotating direction
is counterclockwise, the right port is inlet, the
left port is outlet |
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When the rotating direction is clockwise, the
let port is inlet, the right port is outlet
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All flexible impeller
pumps manufactured by JMP corporation are counterclockwise
at the point of view with endcover ( impeller cover).
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| For good pumping |
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Pipe runs should always be kept as short and
straight as possible, avoiding rising and dipping
over obstructions, as this can lead air-locks.
Pipework should always be reinforced, non-collapsible
hose of the recommended size.
Flexible impeller pumps must not be run dry (more
than 30 seconds). Bilge pumps and water pumps
in particular should always be fitted with a filter
or strainer on the inlet pipework to protect them
from debris. These should be fastened to the boat
structure to ensure their permanent location.
Mount flexible impeller pumps so that some water
is left in the pumpbody when the pump is shut
off. This will prolong impeller life and speed
priming. Pumps must be installed with the overboard
to avoid water siphoning back into the vessel.
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