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?

 

BL00347_

      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

 

ARTICLE  #46: Will Running Pumps Slower (!) Help NPSH problem?

 

ARTICLE #47: Pumps to Systems Interaction, presented by Ibrahim (The Pumpman), June 2009, at CAIRO, Egypt, ASHRAE meeting

 

ARTICLE #48: Human Resources Pointers for the Job Seekers

 

ARTICLE  #49:  Global and Planetary Change – how do we affect it?

 

Readers’ comments are welcome.

 

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