7/23/2019 Pumps - Questions - Answers
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Questions related to Pump/ Alignment/ pump pipingPosted
by:admin13 hours ago inBlog Comments Off
1. What are different types of pumps?Answer: Basially there are
two types of pumps!
A! Centrifugal Pump!B! Positi"e #isplaement pump!2. What are the
different types of centrifugal pump?
Answer: #ifferent types of Centrifugal Pump are:
A! $ingle $tage orB! %ulti&stage3. What is the basic
difference between single stage and multi-stage centrifugal
pump?
Answer: 'he $ingle stage pump has one impeller and
multi&stage pump has two or more impellers in series!'he
disharge of one impeller is the sution of the ne(t one and the head
de"eloped in all the stagesare totaled!4. How many types of
centrifugal pump are available based on the uction and
!ischargearrangement?
Answer: Based on the sution and disharge arrangement) the type
of entrifugal pumps a"ailable is:
A! *nd $ution 'op #isharge!B! 'op $ution 'op #isharge!
C! $ide $ution $ide #isharge!". What are the different types of
casing?
Answer: Casings are generally of two types: "olute and irular!
'he impellers are fitted inside the asings!#. !efine the wor$ing
mechanism of centrifugal pump?
Answer: A entrifugal pump is one the simplest piees of e+uipment
in any proess plant! ,ts purpose is toon"ert energy of prime mo"er
-an eletri motor or turbine. first into "eloity or ineti energy
andthen into pressure energy of a fluid that is being pumped! 'he
energy hanges our by "irtue of twomain parts of the pump) the
impeller and the "olute or diffuser! 'he impeller is rotating part
thaton"erts dri"ers energy into the ineti energy! 'he "olute or
diffuser is the stationary part thaton"erts the ineti energy into
pressure energy!%. How the $inetic energy created by centrifugal
force is converted to pressure energy?
Answer: 'he energy reated by entrifugal fore is ineti energy!
'he amount of energy gi"en to the li+uid isproportional to the
"eloity at the edge or "ane tip of the impeller! 'he faster the
impeller re"ol"es or
the bigger the impeller is then the higher will be the "eloity
of the li+uid at the "ane tip and thegreater the energy imparted to
the li+uid! 'his ineti energy of the li+uid oming out of an
impeller isharnessed by reating a resistane to the flow! 'he first
resistane is reated by the pump "olute-asing. that athes the li+uid
and slows it down! ,n the disharge no00le) the li+uid
furtherdeelerates and its "eloity is on"erted to pressure aording
to Bernoullis priniple!'herefore) the head -pressure in terms of
height of the li+uid. de"eloped is appro(imately e+ual to
the"eloity energy at the periphery of the impeller e(pressed by the
following formula as: 2 "4/ 4g5here)2 'otal head de"eloped in
feet!6 6eloity at periphery of impeller in ft/se!7 Aeleration due
to gra"ity&34!4ft/se48ormula for alulating peripheral "eloity:6
9 #44;5here)
6 Peripheral "eloity in impeller in ft/se!9 'he impeller rpm -??
ft3 of "apor at the same temperature! 'he "apori0ation begins
when"apor pressure of the li+uid at the operating temperature
e+uals the e(ternal system pressure) whihin an open system is
always e+ual to atmospheri pressure! Any derease in e(ternal
pressure or risein operating temperature an indue "apori0ation! 'he
"apor pressure ours right at the impellerinlet where a sharp
pressure drop ours! 'he impeller rapidly builds up the pressure)
whihollapses "apors bubbles ausing a"itation and damage the pump
internals! 'his is a"oided by
maintaining suffiient 9P$2! -Ca"itation implies a"ities or holes
in the fluid we are pumping! 'heseholes an also be desribed as
bubbles) so a"itation is really about the formation of bubbles
andtheir ollapse! Bubbles form whene"er li+uid boils! ,t an be
a"oided by pro"iding suffiient 9P$2!.
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7/23/2019 Pumps - Questions - Answers
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Questions related to wrapping @ oating/ insulation/athodi
protetion: &Part&1
Posted by:admin1> days ago inBlogComments Off
1. What is the procedure for application of wrapping and
coating?Answer: Proedure for appliation of Coating and
wrapping:
A! Prior to appliation of wrapping @ oating) the surfae of pipe
should be made free from all loose%ill sale) dirt) rust) grease)
moisture and other foreign material! 'his is ahie"ed by
blastleaning to grade $a 4 !B! 'he pipe e(terior surfae or blast
surfae shall be oated with primer within four hours of shot
C andblasting! 'he primer shall not be applied when the pipe
surfae temperature is below >
C! when moisture is present on the surfae) the same is heated
for suffiient time to dryabo"e >?
the surfae!C! 'he pipe after priming shall be oated with
two&flood oat of hot enamel inorporating thesimultaneous
appliation of inner @ outer wrapping!2. What is the content of
primer applied on the pipe surface before coating?
Answer: 'he primer onsists of proessed oal tar pith and refined
oal tar oil!3. What is the enamel applied on the pipe surface for
coating?
Answer: 'he enamel is plastiised oal tar pith suitable for hot
appliation and filled with inert mineral filler
whih ha"e minimum tendeny to settle down in fluid state!4. Which
material is used as inner and outer wrapping?Answer: 8ibre glass
tissue onsisting of a uniformly porous mat of hemially resistant
boro siliate glassontaining not less then B4O3!". What should be
the minimum thic$ness of enamel on any point on pipe?
Answer: 'he enamel shall ha"e minimum thiness of 4!D mm when
measured on top of the weld with ano"erall thiness of Dmm!#. How
much should be the depth of pulling of inner )ibre * glass tissue
into the hot enamel?
Answer: 'he inner wrap of 8ibre glass tissue pulled in suh a
manner that the same is imbedded half wayinto the enamel without
touhing the steel surfae!%. What should be the overlap between
inner + outer wrap?
Answer: 'he inner and outer wraps shall be o"erlapped by
4mm!&. What should be the minimum staggering of inner + outer
wraps,
Answer: 'he o"erlaps of the inner and outer wraps shall be
staggered from eah other by minimum distaneof 1??mm!. What is cold
type of wrapping?
Answer: P6C baed bituminous ompound tape used for field wrapping
is alled old wrapping!1. What is the minimum overlap of field
wrapping /cold 0ape on shop wrapping?
Answer:&5 rapping shall start and finish to gi"e a minimum
>mm o"erlap onto the ad=oining shop oating!
Questions related to wrapping @ oating/ insulation/athodi
protetion& Part&4
Posted by:admin1? days ago inBlogComments Off
11. What is the material applied on the flanges or valves to
obtain smooth surface for applicationof cold 0ape?
Answer: %oulding ompound shall be hand applied to obtain the
smooth surfae for appliation of old tape onflanges / "al"es!12.
What is the device used to locate the defects on surface of coating
+ wrapping?
Answer: 2oliday #etetor!13. How much crest voltage of Holiday
!etector shall be set?
Answer: 'he rest "oltage of 2oliday #etetor shall be set as high
as pratial!14. What is the test to ensure the proper thic$ness
adhesion and the position of inner wrap?
Answer: A s+uare of 4mm 4mm shall be ut from wrapping for
determination of thiness) adhesion andposition of the inner wrap!
'his shall be arried out at the rate of one pipe per ? oated!1".
What are different types of nodes used in cathodic protection?
Answer: #ifferent types of Anodes are %agnesium) Ein) 2igh
$ilion ,ron) Aluminum et!
1#. What are nsulating 5as$et 6its?Answer: ,nsulation gaset its
are designed to restrit the effets of orrosion often found in
flanged pipe
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