Pump Articles
Feedback
from the readers:
Dear
Sirs: Congratulations
on the quality of the pump articles!
They are very
clear and combine very well the pump theory
with practical problems. I would also like to see an article about pump running
off BEP point, such as near the pump
run-out, describing
not only the pump aspects but also the electrical
motor consequences: high intensity,
overload, heating etc.
Regards,
Emilio Casado Flores,
Mechanical Manager
CNA and CNT Power Plant, Spain
Article 1: How does pump
suction limit the flow?
One of the claimed advantages of the centrifugal
pumps over positive
displacement pumps is their
ability to operate over a wide range
of flow.
Since a centrifugal pump operates at the intersection
of a pump curve and
a system curve, by varying the system curve
the operating point of the
pump is easily changed.
Article 2: Specific Speed
(NS) - why is it dimensionless, or is it?
Pump specific speed
is one of the several dimensionless
parameters
used in
pumps. Pump designers like to use dimensionless numbers, because it allows
them to analyze and
compare pump performance
regardless
of size.
Otherwise, how would you compare
a 6" pump performance with a 10" pump?
Article 3: Suction Specific
Speed (NSS)
Suction speed is
another dimensionless parameter
used in centrifugal
pumps. Much of the
discussion on specific speed (NS) applies to suction
specific speed
(NSS).
Article 4: What is L3D4 and
why is it good if it is low?
L3D4 (L-cubed over D-to-the-fourth)
is a measure of rotor
stiffness, it’s
ability to resist radial
load and to minimize deflection.
Article 5: Relief Valves for
PD Pumps - internal or external?
Positive
Displacement pumps are knows as
"flow generators", while
centrifugal pumps can be thought as pressure
(or head) generators.
Article 6: Metallurgy - is
316ss soft or hard?
What sort of question is that?! Everyone
knows that 316ss is very soft -
as any austenitic
stainless steel would be. Right? Mmmmm… Why is stainless
steel so good
against cavitation? - if it were
soft, wouldn’t the
imploding bubbles erode the material
away at no time?
Article 7: Lubrication
practices: How Grease-Lubricated Bearings Function
A shielded, grease-lubricated
ball bearing can be compared to a
centrifugal pump having the ball and-cage assembly as
its impeller and
having the annulus between the stationary shield and the rotating
inner
race as the eye of the pump. Shielded bearings are
not sealed bearings.
Article 8: Stable and Un-stable pump curves – why a problem?
This article
came in response to a reader from Europe,
interested to know
when
unstable curves are a problem
and why, - as well as what can be done to avoid, or
minimize, such problems. API 610 frowns on pumps with unstable curves, and in fact prohibits
them from situation where pumps operate
in parallel. When is this a problem and why?
Article
9: The Essence of Equipment Failure Analysis - Theory, Approach, and a Field
Case Study
by
Sourav Kumar
Chatterjee
Manager, Rotating Equipment
Hindustan Petroleum Corporation, Ltd.
Mumbai Refinery, India
Failure is incapability of an item to deliver desired
level of service as specified by
design/expected by user, under specified condition. A thorough
analysis of Root Cause of Failure is
followed by the detailed Field Case Study with a history
of a seal failure of a pump at a refinery.
Human factor, logistics and team
assignment is analysed, along with tracking
technical aspects of a problem. Actual
data for a pump operation around
the failure period
is related to mean time between
failures (MTBF) and a follow-up
monitoring plan, after problem
evaluation and correction, is established. An interesting and informative
case for practicing
plant engineers, maintenance and operating personnel,
to compare notes and learn.
Article #10: PUMP-OUT VANES
– how and why?
This article came out in response
to a question from our reader: ”Could you explain how an ANSI
pump impeller clearance (both open vane impeller
with back pump out vane and reverse vane impeller
with balancing holes) setting affect pump performance? What are
the advantages and disadvantages of these impellers?” - the answer is in the
article.
Article #11: PumpSmart
Module demonstrates energy savings for the Augusta Paper Mill
Article 12: “DYNAMICS OF
ORGANIZATIONAL BEHAVIOR”, - an article by S.Chatterjee, discussing a human
element of the enterprise, and problem solving differences and similarities
across the cultural boundaries.
ARTICLE #13: PARALLEL OPERATION OF CENTRIFUGAL
PUMPS and the Importance of Curve Stability
Article
14: Mean Time between Failures – a Reliability Approach, - another publication by
Sourav Kumar
Chatterjee
Manager, Rotating Equipment
Hindustan Petroleum Corporation, Ltd.
Mumbai Refinery, India
Article 15:
CAVITATION – A DANGEROUS ENEMY TO PUMPS - by:
Robert J.
Hart, P.E.
Robert J.
Hart Enterprises, LLC
Former Principal
Consultant, Dupont Company
ARTICLE 16: IS YOUR PUMP BURNING MONEY AWAY?
– Impeller retrofit can reduce
pump loads, improve seal life, save
your bearings
and couplings, and save significant amounts of money. Your
pump will thank you, and your pump reliability will improve
substantially.
Article 17: What Happens When a Pump Operates
Off-Peak? – more
on pumps operating off-peak.
Article #18: “Pump Reliability – What Does
this Term Mean to You?” – another
article by Robert
J. Hart, P.E.
Article #19: WHAT HAPPENS WHEN a PUMP NO
LONGER OPERATES AT OPTIMUM CONDITIONS (Part 1)
Article 20: WHAT HAPPENS WHEN A PUMP NO LONGER
OPERATES AT OPTIMUM CONDITIONS (Part 2)
Article #21:
Pumps Reliability and Energy Efficiency Improvement Program – How much energy does it cost to run
your pumps? The answer may surprise you.
Article #22: TITANIUM APPLICATIONS -
Titanium offers unique opportunities for
many industrial applications. Among the highlights are…
Article #23: Progressing Cavity Pumps for
Wastewater Treatment
Plants, by Scott
Champlin, President
of Pumping Solutions, Inc., Chicago,
IL
Article #24: Bearing Life Extension and
Reliability Features of Modern ANSI Pumps – by Lev
Nelik, published
in 1993, at 2nd International
Conference of Improving Reliability in Petroleum
Refineries and Natural Gas Plants (download 24 pages in PDF format)
Article #25: Submersible
Pumps (dry or
wet?) for Water
and Wastewater Applications
Article #26: Proper Pump Piping Procedure – 10
steps
Article
#27: Effect of Mechanical Unbalance on Vibrations
Article #28: Roller
Bearings Lubrication”, contributed
by Mike Bensema, FAG Bearings
Article #29: Electric Motor Testing and
Repair Issues, - Motor Repair Techniques, from
EASA
Convention 2003, San Francisco, CA, by Tom Bishop
Article #30: API 8th versus 9th
versus 10th versus ISO: a document that was put together by members
of the API 610 / ISO 13709
JWG. It shows the changes that were
made between API 610, 8th edition
and ISO 13709 (which is essentially API
610, 9th edition). API 610,
10th edition is ISO 13709 adopted back with minor
editorial corrections. All
these standards are technically equivalent.
Article
#31: “To Grease or Not to Grease”
– That is the Question!” – how do YOU grease
the ball bearings?
Article #32: “Have You Seen Chains
Inside Your Pumps Lately?!” - you
can kill the bearings this way!
Article #33: “Pump
Operation Costs as a Function of Operating Flow in Wastewater
Treatment”, a Case Study
Article #34: “Present Challenges and Future
Horizons in the Waste Treatment Industry”
Article #35:
“What do we know and what do we think we know”
Article #36: “Pump Control strategies
Benefit from Compressor
Know-How”, Saul Mirsky, CCC company,
Roper Industries
Article #37: How Much Energy can we Save
by Redesigning (not simply replacing!) Impeller Hydraulics?
Article #38: Newtonian
and non-Newtonian Fluids. Viscosity Effects on Centrifugal Pumps – New Standard
From Hydraulic Institute
Article #39: Parallel
and Series Operation of Pumps, and Operating against Multiple Systems
Article #40:
Bearing Forces Due to Shafts Misalignment
ARTICLE #41: Pump Training – Do You Need
It?
ARTICLE
#42: TRANSIENT START-UP PROBLEMS FOR PUMPS WITH SYNCHRONOUS
MOTORS
ARTICLE
#43: LIFTING WATER –
WHAT ARE YOUR PUMP OPTIONS?
ARTICLE #44: HOW TO EVALUATE VFD SPEED EFFECT ON HYDRAULICS
ARTICLE #45: Focus on Fundamentals: Centrifugal Pumps – Overhung
Impeller
Readers’ comments
are welcome.
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