Answer / bala10286

in case of positive displacement pumps (ex:reciprocating
pump) the piston or mechanical member directly creates the
vacuum or lower pressure such that the water or liquid is
sucked in..
in case of centrifugal pumps...the impeller just
displaces the water due to the centrifugal force..as the
water at center of impeller is displaced to the
casing..partial vacuum gets created at the eye of impeller
and hence suction of new water takes place..
if there is no water around impeller..only air is
present and it cant be displaced by the pump impeller as air
is compressible..the pump impeller is designed to handle
water or liquid.. therefore to remove the air and fill the
casing with water the priming is carried out..
there is no need of priming if there is an foot
valve and its working well...

Answer / bhupendra sahu

To remove the air from pump cavities.

Answer / sriram

priming is done in pumps to remove the entrappped air from
the suction pipe thus aiding in smooth operation and
avoding in excess load on the pump

Answer / abdul hameed

The exact requirement of Priming is "To creat a centrifugal
force by adding a mass"

Answer / chetan mankar

As we know priming means removing air from pumps so as to
enable pump to suck water or liquid.when there is air in
the pump,the head developed by pump is in the terms of
density of air & not in terms of density of water.Bcoz of
this it is not able to developed head & no water being
pumped.

Answer / s.muthupandi

to evacuate the whatever air inside the suction pipe to
create the vaccum in impeler from centrifugal force. it may
be done by two ways by filling water either connecting the
impeler top to vaccum unit (if availbility ). it also not
needed if foot valve is working perfectly

Answer / ab_ina7

to create the sufficient vaccum in the eye of impeller to suck the water and also to avoid cavitation due to entrapped air

Answer / aamir sohi

in case of pumps priming means to remove air from pump cavity in negative head pump,while in case of engines to lubricate all parts before starting or to remove air from fuel lines if maitenance occured

Answer / vikas

the pressure produced in centrifugal pump is propoional to
the density of fluid in contact with impeller, if air comes
in contact with impeller then very less pressure will
produced it result to no discharge through pump.So to
obtain discharge from pump priming is necessacery

Answer / sridhar

Cavitation is a problem in any fluid flowing pipe or
cylinder,which occured becoz of air and priming is used to
create a vacum inside it.

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