Pump Practices & Life

7/28/2019 Pump Practices & Life

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Barringer & Associates, Inc. 2004 1

Pump Practices & Life

Presented by:

Paul Barringer, P.E.

Barringer & Associates, Inc.Reliability, Engineering, and Manufacturing Consultants

P.O. Box 3985

Humble, TX 77347-3985

Phone: 281-852-6810 FAX: 281-852-3749

[email protected] http://www.barringer1.com

Reliability measures the capacity of equipment or processes to operate

without failure for a specified interval when put into service and used correctly.


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Pump Curve Practices & Life-ANSI

% Flow

%H

ead

%R

eliability

Best Efficiency Point

Reliability Curve

0.53

0.1

+ +

++

Weibull

Characteristic

Life ~MTBF

Better Practice

= -20% to +10%

Best Practice

= -10% to +5% of BEP

0.92++

Good (Commercial) Practice

= -30% to +15%

High Temperature Rise

Low Flow

Cavitation

Low Bearing &

Low Seal Life

Lower Impeller Life

Suction

Recirculation

DischargeRecirculation

Low Bearing &

Low Seal Life

Cavitation

Pump Curve

Barringer & Associates, Inc. 1999

ANSI Pump Curve Sensitivity For Pump Reliability

Avoid!!

Reconsider!!

Optimum


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API Pump Curve Practices And Effects On

Pump Life From Variability About BEP

% Flow

%H

ead

%R

eliability


Reliability Curve

1.00

0.90

0.75

+ +

++

Better Practice= -20% to +10% of BEP

Best Practice

= -10% to +5% of BEP 0.98++High Temperature RiseLow Flow

Cavitation

Low Bearing &

Low Seal Life

Lower Impeller Life

Suction

Recirculation


Low Bearing & Low Seal Life

Cavitation

Pump Curve

Life Based On Best Practices For

Installation And Use For All

Features ExceptExcept How Close The

Pump Operates To BEP

Good Practice

= -30% to +15% of BEP


Weibull

Characteristic

Life ~MTBF

Pump Curve Practices & Life-API

Avoid!!

Reconsider!!

Optimum


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High Speed & High Head Pump Curve Practices And

Effects On Pump Life From Variabili ty About BEP

% Flow

%H

ead

%R

eliability


Reliability Curve

?

???

????

+ +

++

Better Practice= -20% to +10% of BEP

Best Practice

= -10% to +5% of BEP ??++High Temperature RiseLow Flow

Cavitation

Low Bearing &

Low Seal Life

Lower Impeller Life

Suction

Recirculation


Low Bearing & Low Seal Life

Cavitation

Pump Curve

Life Based On Best Practices For

Installation And Use For All

Features ExceptExcept How Close The

Pump Operates To BEPGood Practice

= -30% to +15% of BEP


Weibull

Characteristic

Life ~MTBF

Pump Curve Practices & Life?

Avoid!!

Reconsider!!

Optimum


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Reliability Practices On Weibull Life,

Reliability practices must be

connected with costs to find

the lowest long term cost of

ownership calculated by netpresent value.

Pump

Curve %

Off BEP

L/D

Suction

Straight

Runs

Rotational

Shaft

Alignm ent

Piping

Alignment

Rotational

Balance

Foundation

DesignGrouting

Best Practices

Resulting

eta

Multiplier

+5% to

-10% of

BEP

L/D =

10 to 12

0.001

inches/inch

error

0.003 inch

error

Smooth at

0.0198 ips

5 Times

Equipment

Mass

Monolithic

And

Adhesive

EpoxyImpeller 0.9726 98% 100% 100% 100% 100% 100% 100%

Housing 0.8547 86% 100% 100% 100% 100% 100% 100%

Pump Bearings 0.8719 98% 100% 100% 100% 99% 100% 100%

Mech. Seal 0.9533 98% 99% 100% 100% 100% 100% 100%

Bearing Seal 0.8719 98% 99% 100% 100% 100% 100% 100%

Shaft 0.9801 98% 100% 100% 100% 99% 100% 100%

Coupling 1.0000 99% 100% 99% 100% 100% 100% 100%

Motor Bearings 1.0000 100% 100% 100% 100% 100% 100% 100%

Replacement Mtr. 1.0000 99% 100% 99% 100% 100% 100% 100%

Motor Starter 1.0000 100% 100% 100% 100% 100% 100% 100%

Pump

Curve %

Off BEP

L/D

Suction

Straight

Runs

Rotational

Shaft

Alignm ent

Piping

Alignm ent

Rotational

Balance

Foundation

DesignGrouting

Better Practices

Resulting

eta

Multiplier

+10% to

-20% of

BEP

L/D =

6 to 8

0.003

inches/inch

error

0.010 inch

error

Good at

0.0448 ips

3.5 Times

Equipment

Mass

Slightly

Pourous But

Adhesive

Impeller 0.6583 88% 95% 95% 94% 95% 95% 98%

Housing 0.5163 73% 95% 95% 92% 95% 95% 95%

Pump Bearings 0.3950 79% 90% 88% 88% 90% 90% 90%

Mech. Seal 0.4314 88% 90% 90% 84% 90% 90% 90%

Bearing Seal 0.3950 88% 90% 90% 84% 90% 90% 90%

Shaft 0.5705 79% 90% 88% 88% 90% 90% 90%

Coupling 0.6036 92% 95% 90% 94% 95% 90% 91%

Motor Bearings 0.9776 94% 93% 94% 97% 95% 90% 90%

Replacement Mtr. 0.6036 100% 100% 100% 100% 100% 99% 99%

Motor Starter 1.0000 100% 100% 100% 100% 100% 100% 100%

Pump

Curve %

Off BEP

L/D

Suction

Straight

Runs

Rotational

Shaft

Alignment

Piping

Alignm ent

Rotational

Balance

Foundation

DesignGrouting

Good Practices

Resulting

eta

Multiplier

+15% to

-30% of

BEP

L/D =

1 to 3

0.009

inches/inch

error

0.125

inches error

Rough at

0.248 ips

0.5 Times

Equipment

Mass or Stilt-Mounted

Cementitous

& Low

Adhesion

Impeller 0.1949 68% 75% 90% 69% 81% 88% 88%

Housing 0.1438 70% 80% 83% 64% 79% 78% 80%

Pump Bearings 0.0151 65% 60% 58% 40% 61% 50% 55%

Mech. Seal 0.0095 65% 60% 58% 40% 61% 50% 55%

Bearing Seal 0.0151 51% 60% 40% 40% 64% 55% 55%

Shaft 0.1149 65% 60% 58% 40% 61% 50% 55%

Coupling 0.0737 76% 80% 65% 71% 78% 70% 75%

Motor Bearings 0.8625 78% 80% 55% 80% 75% 60% 60%

Replacement Mtr. 0.0737 100% 100% 100% 100% 100% 100% 100%

Motor Starter 1.0000 100% 100% 100% 100% 100% 100% 100%

Avoid



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Summary

Important impacts on life involve:

Equipment grade Installation grade

Operation grade

Maintenance grade

No free lunchessomeone pays foreverything

Think about the life cycle cost of youractionsengineer the results

Remember effects of abuses are

cumulative! You may try to hide

your atrocit ies but the equipment

accumulates the history and

someone pays in the end

Pump Practices & Life

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