HI 1.6(2000)

ANSI/HI 1.6-2000

American National Standard for

Centrifugal Pump Tests 4

Sponsor Hydraulic Institute www.pumps.org

Approved October 27 , 1999 American National Standards Institute , Inc.

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。路fled

American National 8tandard

Approval of an American National Standard requires verification by ANSI that the requirements for due process , consensus and other criteria for approval have been met by the standards developer.

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Consensus is established when , in the judgement of the ANSI Board of Standards Review, substantial agreement has been reached by directly and materially a仟ected interests. Substantial agreement means much more than a simple majority, but not necessarily unanimity. Consensus requires that all views and objections be considered , and that a concerted effort be made toward their resolution. The use of American National Standards is completely voluntary; their existence does not in any respect preclude anyone , whether he has approved the standards or not, from manufacturing , marketing , purchasing , or using products , processes , or procedures not conforming to the standards. The American National Standards Institute does not develop standards and will in no circumstances give an interpretation of any American National Standard. Moreover, no person shall have the right or authority to issue an interpretation of an American National Standard in the name of the American National Standards Institute. Requests for interpretations should be addressed to the secretariat or sponsor whose name appears on the title page of this standard. CAUTION NOTICE: This American National Standard may be revised or withdrawn at any time. The procedures of the American National Standards Institute require that action be taken periodically to reaffirm , revise , or withdraw this standard. Purchasers of American National Standards may receive current information on all standards by calling or writing the American National Standards Institute. (

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Published By Hydraulic Institute 9 Sylvan Way, Parsippany, NJ 07054-3802 www.pumps.org

Copyright 2000 @ Hydraulic Institute AII rights reserved. No pa 此 ofthis publication may be reproduced in any form , in an electronic retrieval system or otherwise , without prior written permission of the publisher. Printed in the United States of America ISBN 1-880952-30-0

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Contents Page Foreword . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. v 1.6

\ d )

Test. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 1

1.6.1

Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 1

1.6.2

Types of tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 1

1.6.3

Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 1

1.6 .4

Hydrostatic test. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

1.6.5

Performance test. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

1.6.6

Net positive suction head required test (optional). . . . . . . . . . . . . . . 19

1.6.7

Mechanical test (optional). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

1.6.8

Priming time test. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

1.6.9

Measurement of rate of flow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

1.6.10

Head -

1.6.11

Power measurement. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 30

1.6.12

Speed measuremen t. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

1.6.13

Temperature measurement and instruments . . . . . . . . . . . . . . . . . . 32

1.6.14

Model tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

Appendix A

References.......................................... 35

Appendix B

Index.............................................. 36

Figures 1.113 - Horizontal unit - (Single or double suction) (Double suction not shown) . . . . . . . . . . . . . . . . . . . . . . 1.114 -

Vertical single suction pump . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

1.115-Ve此ical 竹筒-

.圖 .................4

double suction pump .... . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Test with suction lift. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 11

1.117 一 Open

or closed tank . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 13

叫他一 Pump

performance (all data is corrected to rated speed) . . . . . . . . .. 16

1.119 -

Suppression type NPSH test with constant level sump. . . . . . . . . . .. 19

1.120 -

Level control NPSH test with deep sump supply. . . . . . . . . . . . . . . . . 20

1.121 - Vacuum and/or heat control NPSH test with closed loop . . . . . . . . . . 20 1.122 -

NPSH test with rate of flow held constant . . . . . . . . . . . . . . . . . . . . . . 21

1.123 一-

NPSH test with suction head held constan t. . . . . . . . . . . . . . . . . . . . . 21

1.124 -

NPSH test with flow rate held constant . . . . . . . . . . . . . . . . . . . . . . . . 22

1.125 -

Suction line for static lift test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

1.126 -

Pressure tap opening ..................................... 26

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-l .l l.

1.127 -

Welded-on pressure tap opening . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

1.128 -

Single tap connection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

1.129 一 Loop

1.130 -

/甲魚、

manifold connecting pressure taps. . . . . . . . . . . . . . . . . . . . . . . 30

Gauge connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

Tables 1.18 一-Symbols..................................................

2

1.19 -

Subscripts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 3

1.20 -

Recommended instrument calibration interval .. . . . . . . . . . . . . . . . .. 12

1.21 一- Straight pipe required following any fitting before venturi meter in diameters of pipe . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

1.22 一- Straight pipe required following any fitting before nozzle or orifice plate meter in diameters of pipe . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

1.23 - Straight pipe required following downstream pressure tap of a nozzle or orifice plate meter before any fitting in diameters of pipe . . . . . . .. 28

/月、\、

(一

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IV

Foreword (Not part of Standard) \、白/

Purpose and aims of the Hydraulic Institute The purpose and aims of the Institute are to promote the continued growth and well-being of pump manufacturers and further the interests of the public in such matters as are involved in manufacturing , engineering , distribution , safety, transpo吋ation and other problems of the indust句， and to this end , among other things: a) To develop and publish standards for pumps; b) To collect and disseminate information of value to its members and to the public; c) To appear for its members before governmental departments and agencies and other bodies in regard to matters affecting theindustry; 的

To

e) To f)

increase the amount and to improve the quality of pump service to the public; suppo吋 educational

and research activities;

To promote the business interests of its members but not to engage in business of the kind ordinarily carried on for profit or to perform particular services for its members or individual persons as distinguished from activities to improve the business conditions and lawful interests of all of its members.

Purpose of 5tandards

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1) Hydraulic Institute Standards are adopted in the public interest and are designed to help eliminate misunderstandings between the manufacturer, the purchaser and/or the user and to assist the purchaser in selecting and obtaining the proper product for a particular need. 2) Use of Hydraulic Institute Standards is completely voluntary. Existence of Hydraulic Institute Standards does not in any respect preclude a member from manufacturing or selling products not conforming to the Standards. Definition of a 5tandard of the Hydraulic Institute Quoting from Article XV, Standards , of the By-Laws of the Institute , Section B:. “ An Institute Standard defines the product , material , process or procedure with reference to one or more of the following: nomenclature , composition , construction , dimensions , tolerances , safety, operating characteristics , performance , quality, rating , testing and service for which designed."

Comments from users Comments from users of this Standard will be appreciated , to help the Hydraulic Institute prepare even more useful future editions. Questions arising from the content of this Standard may be directed to the Hydraulic Institute. It will direct all such questions to the appropriate technical committee for provision of a suitable answer. If a dispute arises regarding contents of an Institute publication or an answer provided by the Institute to a question such as indicated above , the point in question shall be referred to the Executive Committee of the Hydraulic Institute , which then shall act as a Board of Appeals. 、、-"

V

Revisions

一

/'

The Standards of the Hydraulic Institute are subject to constant review, and revisions are undertaken whenever it is found necessary because of new developments and progress in the art. If no revisions are made for five years , the standards are reaffirmed using the ANSI canvass procedure. Scope This Standard is for centrifugal , sealless centrifugal and regenerative turbine pumps of all industrial types except vertical multistage diffuser type. It includes detailed procedures on the setup and conduct of hydrostatic and performance tests of such pumps. Several methodologies to test centrifugal and vertical pump equipment are available to pump manufacturers , users and other interested parties. The United States has two sets of pump test standards which represent 的vo approaches to conducting and evaluating pump pe吋Ormance. One , promulgated by the American Society of Mechanical Engineers (ASME) and designated PTC 8.2 , Centrifugal Pumps , provides for two levels of tests in which the test procedures are less restrictive. The ASME Code relies on the pa討ies to the test to agree beforehand on the Scope and Conduct of the test and does not specify how the test results shall be used to compare with guarantee. The ASME is especially suited to highly detailed pump testing , whereas HI Standards detail test scope , conduct and acceptance criteria , and are thus suited to commercial test practices. ASME Codes do not permit the use of acceptability tolerances in reporting results , while the HI Standards do. It is recommended that the specifier of the test standard become familiar with both the ASME Code and the HI Standards before selecting the one best suited for the equipment to be tested , since there are a number of other differences between the two which may a仟8ct the accuracy or cost of the tests. 80th the ASME and HI Standards can be used for testing in either field or factory installations. The detailed requirements of the ASME Test Code are intended to reduce the effect of various installation arrangements on performance results and are applied more to field testing. The HI Standard specifies test piping and more controllable conditions which is more suitable to factory testing. The HI Standards do not address field testing. Surveys have shown that both ASME and HI Standards have been applied successfully to applications from small chemical pumps (1 hp) to large utility pumps (over 5000 hp). Units of Measurement Metric units of measurement are used; and corresponding US units appear in brackets. Charts , graphs and sample calculations are also shown in both metric and US units. Since values given in metric units are not exact equivalents to values given in US units , it is important that the selected units of measure to be applied be stated in reference to this standard. If no such statement is provided , metric units shall govern.

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VI

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Consensus for this standard was achieved by use of the Canvass Method The following organizations , recognized as having an interest in the standardization of centrifugal pumps were contacted prior to the approval of this revision of the standard. Inclusion in this list does not necessarily imply that the organization concurred with the submittal of the proposed standard to ANS I.

、、J

A. R. Wilfley & Sons ANSIMAG Inc. Bechtel Corp Black & Veatch Brown & Caldwell Camp Dresser & McKee , Inc. Carver Pump Company Cheng Fluid Systems , Inc. Crane Company, Chempump Div. Cuma S .A. Dean Pump Div. , Metpro Corp. DeWante & Stowell Dow Chemical EnviroTech Pumpsystems Essco Pump Division Exeter Energy Ltd. Partnership Fairbanks Morse Pump Corp. Fluid Sealing Association Franklin Electric GKO Engineering Grundfos Pumps Corp. lII inois Dept. of Transportation IMC - Agrico Chemical Corp. Ingersoll. Dresser Pump Company ITT Fluid Handling (B & G) ITT Fluid Technology 何T Industrial Pump Group Iwaki Walchem Corp. J.P. Messina Pump & Hyd r. Cons John Crane , Inc. Krebs Consulting Service

KSB , lnc. M.W. Kellogg Company Malcolm Pirnie , Inc. Marine Machinery Association Marley Pump Company Marshall Engineered Products Company Montana State University MWI , Moving Water Industries Oxy Chem Pacer Pumps Paco Pumps , Inc. Pinellas Cty, Gen. Serv. Dept. The Process Group , LLC Raytheon Engineers & Constructors Reddy-Buffaloes Pump , Inc. Robert Bein , Wm. Frost & Assoc. Scott Process Equipment Corp. Settler Supply Company Skidmore South Florida Water Mgm t. Dist. Sta-Rite Industries , Inc. Sterling Fluid Systems (USA) , Inc. Stone & Webster Engineering Corp. Sulzer Bingham Pumps , Inc. Summers Engineering , Inc. Systecon , Inc. Val-Matic Valve & Mfg. Corp. Yeomans Chicago Corp. Zoeller Engineered Products

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VII

This page intentionally blank.

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HI Centrifugal Pump Tests -

1.6 、呵_..?

Test

1.6.1

5cope

This standard is limited to the testing of centrifugal pumps with clear water. The tests conducted under these standards shall be made and reported by qualified personne l. This standard only applies to tests of the pump unless stated otherwise. The type of test(s) performed , and the auxiliary equipment to be used , should be agreed upon by the purchaser and manufacturer prior to the test. It is not the intent of this standard to limit or restrict tests to only those described herein. Variations in test procedures may exist without violating the intent of this standard. Exceptions may be taken if agreed upon by the parties involved without sacrificing the validity of the applicable parts of this standard. 1.6.1.1

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。叫 ective

This standard is intended to provide uniform procedures for hydrostatic , hydraulic , and mechanical performance testing of centrifugal pumps and recording of the test results. This standard is intended to define test procedures which may be invoked by contractual agreement between a purchaser and manufacturer. It is not intended to define a manufacturer's standard practice

Test conditions

Unless otherwise specified , the rate of flow , head , efficiency, NPSHR and priming time are based on shop tests using water corrected to 20 0 C (68 0 F). If the facility cannot test at rated speed because of limitations in power, electrical frequency or available speed change 悶， the pump may be tested at between 80% and 120% of rated speed. It is permissible on pumps greater than 225 kw (300 hp) to test at speeds between 60% and 140% of rated speed.

1.6.3 Terminology The following terms are used to designate test parameters or are used in connection with pump testings:

1.6.3.1

5ymbols

See Table 1.18.

1.6.3.2

5ubscripts

See Table 1.19.

1.6.3.3 5pecified condition point Specified condition point is synonymous with rated condition poin t.

1.6.3.4 Rated condition point

1.6.2 Types of tests

Rated condition point applies to the rate of flow, head , speed , NPSH and power of the pump as specified by the purchase order

This standard describes the following tests:

1.6.3.5 Normal condition point

a) Performance test to demonstrate hydraulic and mechanical integrity; Optional tests as follows when specified:

Normal condition point applies to the rate of flow, head , speed , NPSH and power at which the pump will normally operate. It may be the same as the rated condition poin t.

b) Hydrostatic test of pressure-containing components;

1.6.3.6 Best efficiency point (BEP)

c) Net positive suction head required test (NPSHR test);

The rate of flow and head at which the pump effi ç:iency (ηp) is a maximum.

d) Mechanical test;

1.6.3.7

e) Priming time test.

The condition of zero flow where no liquid is flowing through the pump , but the pump is primed and operating.

For airborne sound testing see HI 9.1-9.5-2000 , Pumps - General Guidelines. 、包地旬.../

1.6.2.1

2000

5hut

。何 (50)

Table 1.18 -

Symbols

Symbol

Term

Metric unit

Abbreviation

US Customary Unit

Abbreviation

Conversion factora

A ß(beta) D ~ (delta)

Area Meter or orifice ratio Diameter Difference

mm L

645.2

In

25 .4

E仟iciency

g y(gamma) h H n NPSHA

Gravitational acceleration Specific weight Head Total head Speed Net positive suction head available Net positive suction head required Specific speed NS = nQ Yo /H% Kinematic viscosity pi =3.1416 Pressure Power Rate offlow Rate offlow Density Specific gravity Temperature Torque Velocity Exponent Elevation gauge distance above or below datum

% ftlsec 2

0.3048

口1

square inches dimensionless inches dimensionless percent feetlsecond/sq uared pounds/cubic foot feet feet revolutions/minute feet

in L

η(eta)

square millimeter dimensionless millimeter dimensionless percent meter/second/sq uared

m

feet

NPSHR NS v (nu) π

p P q Q p (rho) s τ(tau)

V X

Z

a Conversion factor x US units = metric units.

meter meter revolutions/minute meter meter dimensionless millimeter squared/sec dimensionless kilopascal kilowatt cubic meter/hour cubic meter/hour kilogram/cubic meter dimensionless degrees Celsius Newton - meter meter/second none meter

mm % m/s 2 口1

們1

rpm

m行， 2/S

kPa kW m3/h m3/h kg/m 3 。C

N.m m/s none 口1

dimensionless feet squared/second dimensionless pounds/square inch horsepower cubic feetlsecond US gallons/minute pound mass/cubic foot dimensionless degrees Fahrenheit pound-feet feetlsecond none feet

Ibl代3

R R rpm

0.3048 0.3048

前

0.3048

R

0.3048

ft2/ sec

1.162 92 ,900

pSI hp 代3/S ec gpm Ibm/ft3

6.895 0.7457 101.94 0.2271 16.02

。F

Ib-ft ftlsec none 代

CF-32) x 1.356 0.3048 0.3048

%

gz-MOOO 工502 月三 CGω-EE→U

1\.)

HI Centrifugal Pump

Tests 一 2000

1.6.3.8 Volume

1.6.3.11

The unit of volume shall be one of the following:

The reference line or center of the pump shaft from which all elevations are measured. The elevation head (Z) to the datum is positive when the gauge is above datum and negative when the gauge is below datum.

Metric: cubic meter;

Datum

US units: US gallon; The datum elevation is defined as follows: US units: cubic foo t. The specific weight of water at a temperature of 20 C (68 F) shall be taken as 9.89 kN/m 3 (62.3 IbIft3 ). For other temperatures , proper specific weight corrections shall be made using values from the ASME steam tables. 0

For horizontal units , it shall be the centerline of the pump shaft , Figure 1.113.

0

1.6.3.9 Rate offlow (capacity) (Q)

For vertical single suction pumps , it shall be the entrance eye to the first stage impeller, Figure

1.114. For vertical double suction pumps , it shall be the center of the impell前， Figure 1.115.

The rate of flow of a pump is the total volume throughput per unit of time at suction conditions. It assumes no entrained gases at the stated operating conditions.

1.6.3.10 Speed (n) The number of revolutions of the shaft in a given unit of time. Speed is expressed as revolutions per minute

1.6.3.12

Head (h)

Head is the expression of the energy content of the liquid referred to a datum. It is expressed in units of energy per unit weight of liquid. The measuring unit for head is meter (feet) of liquid:

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Table 1.19 - Subscripts Term

Subscript

Term

Test condition or model

口10t

Motor

2

Specific condition or prototype

ot

Operating temperature

a

Absolute

OA

Overall unit

at訂1

Atmospheric

p

Pump

b

Barometric

S

Suction

d

Discharge

dvr

Driver input

V

Velocity

g

Gauge

vp

Vapor pressure

max

Maximum

W

Water

mm

Minimum

Subscript

、'、--

Theoretical

3

HI Centrifugal Pump Tests -

2000 1.6.3.12.1

Gauge head (hg) ~

--<

The pressure energy of the Ii quid determined by a pressure gauge or other pressure measuring device.

(Metric) hg

= 旦旦

9.8s

(US units) h (J ~

1.6.3.12.2

乙

一( 2.31 )(62.3)(P g )

=

"v'

r

一

2.31 (Pg)

s

Velocity head (hv)

The kinetic energy of the liquid at a given section. Velocity head is expressed by the following equation:

and datum elevation

。 h.. = 之一

2(g)

v

1.6.3.12.3 Figure 1.113 - Horizontal unit - (Single or double suction) (Double suction not shown)

Elevation head (Z)

The potential energy of the liquid due to its elevation relative to a datum level , measured to the Ii quid surface or center of the pressure gauge. 1.6.3.12.4 Total suction head (hs)

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Pump centerline

The total suction head is the algebraic sum of the suction gauge head , the suction velocity head , and the suction elevation head: hs = h_ + h.. + Z_ ξ"s

六司 Datum

.S

The gauge head is positive when the suction ga uge reading is above atmospheric pressurE; and negative when the reading is below atmospheric pressure. ,

Figure 1.114 - Vertical single suction pump

Pump centerline

The velocity head is computed for the liquid velocity at the point of gauge attachmen t. On pumps submerged in an open sump or open wet well , where the suction piping is considered pa吋 ofthe pump:

hs

= Zw

Where:

Zw =

Vertical distance of the sump free water surface from datum. /刑前h\\

Figure 1.115 - Vertical double suction pump

4

HI Centrifugal Pump Tests 1.6.3.12.5 Total suction lift 、

、司_/

When the total suction head is negative , it is often called total suction lift. 1.6.3.12.6

Total discharge head (h d)

The total discharge head is the algebraic sum of the discharge gauge head , discharge velocity head , and the discharge elevation head. It is computed for the liquid velocity at the discharge pressure tap , and the elevation head Zd' measured at the pressure gauge:

h....d

1.6.3.12.9 Effects of compressibility of liquid on total head In the preceding formulas , the work accomplished in compressing the liquid has been ignored. To evaluate the total head more accurately when pumping to high pressure , this factor should be taken into consideration. For most liquids , it may be assumed that a straight line relationship exists between pressure and volume. With this assumption , the above total head formula becomes:

= h_ +h.. - "gd ' "vd +Z

H 1.6.3.12.7

a) Where positive suction head exists , the total head is the total discharge head minus the total suction head:

、\、.../

=

r~叭門

Total head (H)

This is the measure of the work increase per unit weight of the liquid , imparted to the liquid by the pump , and is therefore the algebraic difference between the total discharge head and the total suction head.

H

2000

= hd-hs

It is suggested that this relationship be used if the dif.圖 ference between Yd and 芯， near best e仟iciency point , is 0.2% or more. Example: (Metric) Correction of total head for compressibility. Given Water Conditions: ts = 1770 C (suction temperature);

Ps = 1380 kPa (suction pressure);

or

td = 182 C (discharge temperature);

H=(hgd+hvd+Zd)(hgs+hvs+Zs)

Pd

Combining terms , the general expression for total head is:

At suction conditions:

0

= 32400 kPa (discharge pressure);

Ps = 1480

kPa;

九=

17rC

H=(hgd-hgs)+(hvd-hvs)+(Zd-Zs) 的

for

pumps submerged in sumps:

H = h_:1 d +h"Vd +Z，， -Z山 c) Where negative suction head exists , the total head is the total discharge head plus the total suction lift. Since the complete characteristics of a pumping system determine the total head requirements , this value can only be specified by the user.

From steam tables , Suction specific volume = 890.5 kg/m 3 At discharge conditions: Pd

= 32500 kPa;

td = 1820 C

From steam tables , Discharge specific volume = 904.5 kg/m 3 Specific volume = 1/specific weight = 1/ythen:

1.6.3.12.8 Atmospheric head (h atm ) Local atmospheric pressure expressed in meters (feet). \

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5

HI Centrifugal Pump Tests -

2000 1.6.3.12.10 (NPSHA)

hvs)and (Zd

Zs)

to obtain the total head.

NPSHA

Example: (US units) Correction of total head for compressibility. Given Water Conditions:

ts = 350

0

=200 psig (suction pressure);

td

=360

Pd

0

-a

F (discharge temperature);

= Total suction head in Meters (feet) absolute

or

=4700 psig (discharge pressure);

= hatm+hs-hvp

NPSHA

At suction conditions:

=215 psia;

Example: (Metric) A four-stage boilerfeed pump having a 100-mm inside diameter suction and a 75mm inside diameter discharge is rated at a flow rate of 91 m 3/h against a total head of 274 m handling water at 116 C , and running at 3550 rpm. The suction gauge reading is 145 kPa and the gauge center location is 0.15 m below impeller inlet datum , and atmospheric pressure is 98 kPa. 0

已= 350 F 0

From steam tables , Suction specific volume = .01800 ft3/lb

=4715 psia;

NPSHA 的=

1000 (gxp)'

= 一一一一 (Pt:>-

0

360 F

From steam tables , Discharge specific volume .01772 位3/lb

=

P vp

P ,m) + h ", vμ

。

= 172 kPa (from steam tables)

y = Specific weight = 947.3 kg/m 3 Velocity in the 100-mm inside diameter suction:

(Pdf)?+ 主l

v=

91

2

(h v5') = 2g ~一

β 2 一 門/』nu

to obtain the total head.

vs

一月4

(hll.-h ll.5 ) and (Z卅一 Z，，) •a

h

qu一×

value should be added to the terms:

3.2 m/s .,

一一

γhis

=

0.1 叫 :36OO

Velocity head

6

a

Specific volume = 1/specific weight = 1/ythen:

(.01772 + .01800) 2 = 1 1 ,57O ft

~\

To calculate the net positive suction head available (NPSHA) to the pump in the field:

At discharge conditions:

Pd

h"n

= hatm+h s

Reference: Keenan and Keys , Steam Té的les， Thermodynamic Properties of Wate r, John Wiley and Sons , lnc.

Ps

= h~-a -

Where:

h ",

F (suction temperature);

Ps

~.

Net positive suction head available (NPSHA) is the total suction head of liquid absolute , determined at the suction nozzle and referred to datum , less the absolute vapor pressure of the liquid in head of liquid pumped:

This value should be added to the terms: (hvd

Net positive suction head available

--

nuFOn/-

m

h_=h_+h..+Z~ :3 8

.S

r=\ 1000 ì1+0.52-0.15 = 16 .2 m h_ = 144.8xl( IVVV - \..947.3 x 9.81) s

HI Centrifugal Pump

NPSHA =

1000 9.81 x 947.3 ,...

，， ;V~VA'" ,, (98-172)

+ 16.2 = 8.2 m

、、、-/

Examp給: (US units) A four-stage boiler feed pump having a 4-inch inside diameter suction and a 3inch inside diameter discharge is rated at a flow rate of 400 gpm against a total head of 900 feet handling water at 240 o F, and running at 3550 rpm. The suction gauge reading is 21 psig , the gauge center location is 0.5 feet below impeller inlet datum , and atmospheric pressure is 29 inches Hg.

29 12

13.6 2.31

= 一×一一一=

P ", tm = 29" of Hg é:J L fTI

NOTE: specific gravity of

mercu 叩=

13.58 and

y = Specific weight = 59.1 Ib/ft3 Velocity in the 4-inch inside diameter suction: 400 x .321

v= 一一一一=

Velocity head (hv)

s'

2 x 32.2

s

1.6.3.12. 刊

Electric driver input power (P mot)

The electrical input to the driver expressed in kilowatls (horsepower). 1.6.3.13.3

Pump output power (Pw)

The power imparted to the liquid by the pump. It is also called water horsepower. (Metric) P w

QxHxs

=一一一一

367

(US units) P w w 1.6.3.13.4

QxHxs

= 一一一-

3960

Pump efficiency (llp)

The ratio of the pump output power (Pw) to the pump input power (P p); that 峙， the ratio of the liquid horsepower to the brake horsepower expressed in percen t:

1.6.3.13.5 1.6 feet

21 x 144 59.1

144 59.1

The power delivered by the driver to the pump input shaft. It is also called brake horsepower.

2g

= 一一;.( 14.2 -

Overall efficiency (1l 0A)

The ratio of the pump output power (Pw) to the energy supplied to the driver (P mot) expressed in percen t. This e仟iciency takes into account losses in both the pump and the driver:

一一一一一+ 1.6 一 0.5

NPSHA

Pump input power (P p)

ηp 乎 x 100 .p

,,2 = 二一

h_=h_+h..+Z_

s

1.6.3.13.1

10.2 ftlsec

:(4)2

hv= 旦旦旦=

Power (P)

Pvp)+hs

Pvp = 25.0 psia (from steam tables) \~

1.6.3.13

1.6.3.13.2

To calculate the net positive suction head available (NPSHA) to the pump in the field: 144 NPSHA=7(Pa

pressure of the liquid in head of liquid pumped , required to prevent more than 3% loss in total head from the first stage of the pump at a specific rate of flow.

14.2 psia

ft of liquidx s 2.31

P atm in psi rm ... ,..._.

Tests 一 2000

= 52.3 feet

p…

η OA = 古主• mot

x 100

25.0) + 52.3 = 26.1 feet

Net positive suction head required

1.6.4 1.6.4.1

Hydrostatic test Hydrostatic test objective

(NPSHR)

\-.-/

Net positive suction head required (NPSHR) is the total suction head of liquid absolute determined at the first stage impeller datum less the absolute vapor

To demonstrate that the pump when subjected to hydrostatic pressure(s) will not leak or fail structurally. For purposes of this requirement , the containment of liquid means only prevention of its escape through

7

HI Centrifugal Pump Tests -

2000 when no leaks or structural failure are observed for a minimum of 3 minutes for pumps 75 kW (100 horsepower) and below, or 10 minutes above 75 kW (100 horsepower).

the external surfaces of the pumps , normally to atmosphere. 1.6.4.2

Hydrostatic test parameters

Each part of the pump which contains liquid under pressure shall be capable of withstanding a hydrostatic test at not less than the greater of the following:

Test Iiquid: Test liquid shall be water or oil having a maximum viscosity of 32 Cst (150 SSU) at test temperature.

150% of the pressure which would occur in that part when the pump is operating at rated condition for the given application of the pump , except thermoset pa 吋s.

Temperature: If the part tested is to operate at a temperature at which the strength of material is below the strength of the material at room temperatu 舟， the hydrostatic test pressure shall be multiplied by a factor obtained by dividing the allowable working stress for the material at room temperature by that at operating temperature. This pressure thus obtained shall then be the minimum pressure at which hydrostatic pressure shall be performed. The data sheet shall list the actual hydrostatic test pressure.

125% of the pressure which would occur in that part when the pump is operating at rated speed for a given application , but with the pump discharge valve closed. Due to the irreversible damage that can occur to the reinforcement of thermoset parts that are put under excessive pressure , hydrostatic test pressure shall be 1.1 times the maximum design pressure. The manufacturer should be able to verify through test records that adequate sampling was done to prove that the pa 前s can sustain 1.5 times the design pressure. When a 1.5 hydrostatic test pressure on thermoset parts is requested , all parties should agree to the consequences of possible irreversible damage. In all instances , suction pressure must be taken into accoun t.

1.6.4.3

Components: The test shall be conducted on the liquid-containing components such as the casing and end covers. Care must be taken not to impose pressure in excess of 150% of design on areas designed for lower pressure operation. Test flanges or cylinders can be used for isolating differential pressure. Assembled pump: The test shall be conducted on the entire liquid-containing area of the pump , but care must be taken not to impose pressure in excess of 150% of design on areas such as suction volutes or mechanical seal areas.

8

/舟、

Hydrostatic test records

Complete written or computer records shall be kept of all pe此inent information and kept on file , available to the purchaser by the test facility, for two years. This information shall include: 的

Identification

by model , size , serial number;

b) Test liquid; c) Maximum allowable working pressures and temperature; d) Hydrostatic test pressure and test duration; e) Date of test; f)

Test duration: Test pressure shall be maintained for a sufficient period of time to permit complete examination of the parts under pressure. The hydrostatic test shall be considered satisfacto叩

Hydrostatic test procedure

Items to be tested shall have all the openings adequately sealed. Provisions shall be made to vent all the air at the high points on the item. The item shall be filled with the test liquid , pressurized , and the test pressure shall be maintained for the duration of the test. No leakage through the item tested shall be visible; however, leakage through the stuffing-box packing shall be permitted. 1.6.4.4

Components or assembled pumps: The test shall be conducted on either the liquid-containing components or the assembled pump.

/"\

Identity of personnel in charge. f何四、\

HI Centrifugal Pump Tests 1.6.5

2000

Performance test Performance Tolerance (continued)

、、、啥_/

1.6.5.1

Performance test acceptance tolerances

150 m (500 ft) and over, any f1 0w rate

+

Minimum efficiency at rated rpm and rate of f1 0w

Tl p or Tl OA

、、自'，

1.6.5.3

+

nu

The purchaser or purchaser's designated representative may witness the test when requested by the purchaser in the purchase order.

+5% ，一 o

、

\ __/

Witnessing of tests

From 60 m (200 ft) to 150 m (500 ft) , any f1 0w rate

rt

1.6.5.2

+5% ，一3%

呵，』nu

When testing at rated speed is not practical , test speed shall not be less than 80% nor more than 120% of the rated speed. It is permissible on pumps greater than 225 kW (300 horsepower) to test at speeds between 60% and 140% of rated speed. Results are to be adjusted to rated speed. Any greater change in speed shall be by mutual agreemen t.

+5% ，一 o

-HDB nunuo d1dnuhHr nunu U6a I'm nHnonH m 內W

The minimum number of test points for level “A" shall be 7 , and the minimum number for level “B" shall be 5. See Section 1.6.5.3 for descriptions of levels A and B.

B

I

While pumps must be closely checked for satisfactory mechanical operation during performance testing , the degree and extent of such checking is independent of the level of acceptance tolerances.

A

6n 山 得 前 mm

The acceptance tolerance applies to the specified condition point only, not to the entire performance curve.

Acceptance level

3% ，一 O

5% ，一3%

+3% ，一O

(For Level

A， ηp

=contract pump efficiency)

(For Level

B ， ηp

= published , nominal efficiency)

c) Alternatively, the pump test results may be judged at rated total head and rpm versus rate of flow as follows: Performance Tolerance

Acceptance levels

The pe吋Ormance test has two levels of acceptance , A and B , for the quantitative values. Acceptance level “A" is usually applied to those pumps that are manufactured for specific conditions of service. Acceptance level “ B" is usually applied to those pumps that are mass produced for stock. If not specified , level A will apply. a) In making level "A" tests , no minus tolerances or margin shall be allowed with respect to rate of f1 ow, total head or efficiency at the rated or specified conditions; b) Acceptance of the pump test results shall be judged at rated rate of flow and rpm with applicable total head and efficiency as follows:

B

A

Acceptance level

10 ，一 0%

Rate of flow tolerance at rated total head

+

Minimum efficiency at rated rpm and total head

Tl p or Tl OA

.

+

5 ，一5%

(亨)一 0.2

d) Examples in metric units follow for a pump rated 227 m"/h , 30.5 m , 80% efficiency, water with 1.0 specific gravity: 1) Per Para b , level A at rated rate of flow and rpm , test total head range; 30.5 x 1.08

=33 m max;

Performance Tolerance Acceptance level \-./

Under 60 m (200 ft) to 680 m3/h (2999 gpm)

o

A

B

+8% ，一 o

+5% ，一3%

30.5 x 1.0 2)

=30.5 m min;

Per Para b , level B at rated rate of flow and rpm , test total head range;

9

HI Centrifugal Pump

Tests 一一 2000

30.5 x 1.05 = 32 m max; 30.5 x .97 = 29.6 m min; Based on minimum efficiency =

Examples in US units follow for a pump rated 1000 gpm , 100 ft , 80% efficiency, water with 1.0 specific gravity:

~\

1) Per Para b, level A at rated rate of flow and rpm , test total head range;

100/[(120/80) - .2] = 76.9%; 100 x 1.08 = 108 ft max; Test power range = 22.8 kW min; 25.7 kW max. 3)

Per Para c , level A at rated total head and rpm.

2) Per Para b, level B at rated rate of flow and rpm , test total head range;

Test rate of flow range at rated total head:

100 x 1.05 = 105 ft max;

227 x 1.1 = 250 m3/h max;

100 x .97 = 97 ft min;

227 x 1.0 = 227 m3/h min;

Based on minimum efficiency =

Test power at rated total head and rpm =

100/[(120/80) - .2] = 76.9%;

Pw

(加 and: 227 x 30.5 = 23.6 kW min;

367 × (2旦) 100

250 x 30.5 = 26 kW max:

(們

367x 100 4)

100 x 1.0 = 100 ft min:

Per Para c , level B at rated total head and rpm.

Test power range = 30.6 hp min; 34.5 hp max. 3) Per Para c , level A at rated total head and rpm. /"'""叫

Test rate of flow range at rated total head: 1000 x

1.1= 竹 00

gpm max;

1000 x 1.0=1000 gpm min; Test power at rated total head and rpm =

Pw

(泓)

Test rate of flow range: (1000)(100) =31.6hp m-n; 227 x 1.05 = 238 m3/h max;

(396叫:2)

227 x .95 = 216 m3/h min;

and:

Test max power at rated total head and rpm =

(11 00)(100) =34.7hp max,

238 x 30.5 = 25.7 kW;

(3的0)(芯)

叫76.9) 100

Test min power at rated total head and rpm =

Test rate of flow range:

216 x 30.5 = 22.4 kW;

1000 x 1.05 = 1050 gpm max;

367(旦) 100 10

4) Per Para c, level B at rated total head and rpm.

1000 x .95 = 950 gpm min;

~\

HI Centrifugal Pump Test max power at rated total head and rpm

=

(1050)(100) J 、= 34.5 hp; (76.9'\ (3960)1 一一| \. 100)

\、..--'

pe吋。 rmance

(950)(100) J 、= 30 hp; (80 '\ (3960)1 一一| \.100) Note that the driver horsepower required is dictated by the acceptance level specified and the tolerances.

If it is necessa叩 to dismantle a pump after the pe斤。 r­ mance test for the sole purpose of changing rotation or machining impellers to meet the tolerances , no re-test shall be required unless the reduction in diameter exceeds 5% of the original diameter.

1.6.5.4 Peñormance test instrumentation 1.6.5.4.1

、、..-/

Introduction

Test instruments shall be selected so that they can provide measurements with accuracy shown in Section 1.6.5 .4 .2 at BE P. Instruments need not be calibrated specifically for each test , but are to be periodically calibrated by the manufacturer or suitable pa叫y. Refer to Section 1.6.5 .4 .3 for suitable interval between calibrations for pe吋ormance test instruments.

1.6.5.4.2 Fluctuation and accuracy

Actual Measurement

Acceptable f1uctuation of test readings :1:% ofthe values

Accuracy of the instrument as a :1:% ofthe values

Rate offlow

2.0

1.5

Differential head

、、.../

computation of efficiency for fulfillment of the manufacturer's guarantee and to disregard the e仟ect of instrument accuracy.

1.6.5.4.3 Suitable interval between calibration for

Test min power at rated total head and rpm =

5)

Tests 一-2000

test instruments

Measuring and test equipment and measurement standards shall be calibrated at periodic intervals as listed in Table 1.20. Intervals shall be shortened as required to ensure continued accuracy as evidenced by the results of preceding calibrations and may be lengthened only when the results of previous calibrations provide definite indications that such action will not adversely a仔ect the accuracy of the system.

1.6.5.5 Peñormance test setup This section contains general guidelines for performance test setup , to ensure accurate and repeatable test results. See Figures 1.116 and 1.117. The performance test may utilize , but is not limited; to , the following: a)

Facility or purchaser-furnished driver. Depending on the method used to measure pump input power, efficiency data may be required;

b) Facility or purchaser-furnished speed-change unit, if required. To accurately establish pump input power, efficiency data of speed changer may be required; c) A suction pipe or hose from the booster pump , closed tank or open sump , properly sized for the pump being tested. The f10w into the pump is to be free from swirl and have a symmetrical velocity distribution; Priming connection Suction

2.0

}Rerr1 州州em

1.0

same as Figure 1.117

or 1.119

Discharge head

2.0

0.5

Suction head

2.0

0.5

lnput power

2.0

1.5

Pump speed

0.3

0.3

NOTE: Since e仟iciency itself is a derived quantity, its accu.racy may be computed from the other instrument accuracies listed in the table , applying the root mean square law. It is common practice to use the actual recorded test readings for

訓/ -1 ~

_ Water

level variance

J Optional baffle: spacing between

Optional throttle valve

Figure 1. 刊 6 -

suction and discharge pipes is to be equal to or greater than 6 times the sum of the nominal pipe diameters. When spacing must be reduced , a baffle as shown is required Test with suction lift

11

HI Centrifugal Pump Tests -

2000

d) A suction pressure gauge , compound gauge or pressure transducer suitable for measuring the complete range of pressures whether positive or negative;

Table 1.20 -

e) A discharge pipe or hose with a pressure breakdown (throttling) device; f) A discharge pressure gauge or pressure transducer(s) for measuring the complete range of pressures;

Recommended instrument calibration interval 3 Power (continued)

Rate offlow Quantity meter

1 yr

Torque bar

Weighing tanks

1 yr

Calibrated motor

Not req'd b

Volumetric tank

10 yr

KW Transducer

3 yr

Wa吐-amp-volt， po此able

1 yr

Wa吐-amp-volt，

1 yr

Rate meters Venturi

c

Nozzle

c

Strain gauges

6mo

Orifice plate

c

Transmission gear to 375 kW (500 HP)

10 yr

Weir

c

Transmission gears above 375 kW (500 HP)

20 yr

permanent

Turbine

1 yr

Magnetic flow

1 yr

Tachometers

3 yr

Rotometer

5 yr

Eddy current drag

10 yr

Propeller

1 yr

Electronic

Ultrasonic

5 yr

Frequency responsive devices

Manometers Dead weight tester

Electronic

10 yr

Not req'd

Photocell

10 yr

Stroboscopes

5 yr

Power Dynamometer w/scale

6 yr

Dynamometer w/l oad scale

6mo

1 yr

Torque meter (speed)

1 yr

Temperature Electric

2 yr

Mercury

5 yr

a Use instrument manufacturer's recommendation if shorter than listed above. b Unless electrical or mechanical failure. C

Calibration is not required unless it is suspected there are critical dimensional changes.

12

----~、

Not req'd b

4mo

4mo

Digital indicator

/

10 yr

1 yr

Transducers

Speed

Vibrating reed

Pressure Bourdon tube (pressure gauge)

r--\

戶無恥\

HI Centrifugal Pump

Tests 一-

2000

Pressure Gauge Thermometer

Dampening Valve

Control Valve lor Throttling Suction

Pressure Gauge

Dampening Device _ Flow Meter il I Located in Discharge

on Test I I 2 lJ I

…

D叫e刊C ∞叫 圳 o 伽 n

Spring Loaded Back Pressure Valve or Adjustable Choke Valve

Ad 吋IJUS 剖tabl怡 e

Return to sump

Discharge

Figure 1.117 -

\、.../

g) Throttling devices may be used for the suction and discharge instruments , such as needle valves or capilla 叩 tubes to dampen out the pressure pulsations; h) A means for measuring input power to the pump shall be provided and be suitable for measuring the complete range of power; i) A means for measuring pump speed shall be provided;

Note: Position 01 these devices may be reversed in some set ups

Open or closed tank 1.6.5.6

Performance test data requirements

The following data shall be obtained prior to the test run and writlen for the record to be retained for two years (see sample data sheet on page 14): a)

Record of pump type , size and serial number;

b) To verify the liquid prope此ies ， the temperature of the liquid shall be taken before and after testing. Temperature readings should be taken more often when testing for NPSHR or high-power pumps.

j) Test setups intended for NPSH testing shall be provided with a means for lowering the suction pressure to the pump , such as a suction throtlle valve (with optional screen or straightening vanes) , variable level sump in an open system , or a closed tank with a mechanism to create a vacuum or pressure; k) A means for measuring the temperatu陀 liquid shall be provided;

ofthe

d) Records of critical installation dimensions , such as tank internal dimensions , pipe internal dimensions and lengths , and liquid levels (submergence) relative to datum;

test

1) The actual dimensions of the suction and discharge pipes where pressure readings are to be taken shall be determined so that proper velocity head calculations can be made; '-......./ m) Flow measuring device(s).

c) Ambient conditions , such as temperature and barometric pressure;

e) Record of driver data , such as type , serial number, horsepower, speed range , amperage , voltage and efficiency; f)

Record of auxiliary equipment , such as vibration monitors , temperature sensors , low- or highpressure monitors , leakage detectors , alarms , etc.;

13

HI Centrifugal Pump

Tests 一-2000

Summary of necessary data on pumps to be tested /""""、

The following information should be furnished on pumps to be tested: General: 1 . Owner's name 2. Plant location 3. Elevation above sea level 4. Type of service Pump:

胎一

t s 1e as eeht sye b

w

納

-Ttququ

悶-吋

aee

Manufactured by Type 一一一一一 Serial number Speed ratio Efficiency

、，

1. 2. 3. 4. 5.

Gen1234 什

Intermediate transmission:

Test information should be listed substantially as follows: E

Manufactured by Manufacturer's designation Manu伯 cturer's serial number Arrangemen t: horiz. 一一一一 vertical Inlet: single doubl~ Number of stages 一一一一 Size suction: nominal actual 8. Size discharge: nominal actual

Test information

閒叭 D7T

1. 2. 3. 4. 5. 6. 7.

9. Net positive suction head required (NPSHR) 10. Total discharge head (h d ) 11. Total head (H) 12. Output power (P w) 13. Efficiency (llp) 14. Input power (P p ) 15. Speed

AU hUVJ

Rate of flow:

-

G

1. Method of measurement 2. Meter-make and serial number 3. Calibration data

/'“悟、、

Head: 1. Suction gauge-make and serial number

Driver: 1. Manufactured by 、 2. Serial number 3. Type: motor 一一一 turbine 一一 other 4. Rated horsepower 5. Rated speed 一一 6. Characteristics (voltage , frequency , etc.) 一一一一 7. Calibration data 8. Driver efficiency

2. Calibration data 3. Discharge gaug e-make and serial number 4. Calibration data

Power: 1. Method of measurement

Specifying rated conditions

2. Make and serial number of instrument

The following information is necessary in specifying rated conditions:

3. Calibration data

1. Liquid pumped (water, oil , etc.) 2. 3. 4. 5. 6. 7. 8.

14

Speed:

Specific weight Viscosity at pumping temperature

1. Method of measurement

Temperature 一

2. Make and serial number of instrument

Vapor pressure Rate of flow Total suction lift (hs) Total suction head (hs)

3. Calibration data

/串門

HI Centrifugal Pump g) \、四旬~/

h)

Instrument calibration records and correction factors in accordance with instrumentation calibration section; Identity and authority level of test personnel in charge of tests;

~

33 ,000

5250

Where:

Peñormance test records

Complete written or computer records shall be kept of all information relevant to a test and kept on file , available to the purchaser by the test facility, for two years.

:"~~';:'~'

p

i) The actual dimension of the areas where pressure readings are to be taken shall be determined so that proper velocity head corrections can be made.

1.6.5.7

n 干

2nLWn

(US units): P n

Tests 一-2000

L

=

Length of lever arm in m

W

=

Net force in N (Ib);

n

=

Pump speed in rpm;

,.

=

Torque in N.m (pound-feet).

(的;

The electrical horsepower input to an electric motor is given by: (Metric)

P mot

kW

-J

mo -- -nu

w一明

p

US UnH s

=

bn 一

The manufacturer's serial number, type and size , or other means of identification of each pump and driver (if calibrated and used to obtain the pump's efficiency) involved in the test shall be recorded to avoid mistakes in identity.

Where: While these records apply to the complete unit, including the driver, the standard itself applies only to tests ofthe pump.

kW

=

Electrical input power in kilowatts.

The input power to a pump driven by an electric motor \

j

1.6.5.8

Calculations

1.6.5.8.1

IS:

Calculation of total suction head (hs)

Pp

h~ =

h_ +h.. ò:1 S

1.6.5.8.2 hd

.J

•

s

Calculation of total discharge head (h d )

1.6.5.8.5 Calculation of output power The liquid horsepower (Pw) is computed by the fo ll.owing formula: 的

H

=

P…×旦旦t mUL 100

+Z~

= "gd. h_ +h.. .J "v d +Z . ~d

1.6.5.8.3

=

Metric

units:

Calculation of total head (H)

hd-hs

b) US units: haω-

的Md­

α. 卅一

-m

hdzw 一

.'-

×

文u

nE

MU

lum 的一: &山 m 一

一

(Met川 nits): 月=計布

P... = W

P 一

The input power (P o) , when measured by transmission dynamometer, is calculated from the following formula:

心 da

μ仰

1.6.5.8.4 Calculation of input power

fm.丸

For definition of terms and algebraic summation of the parts , see Section 1.6.3.12.

P=QH(S) w 366

df

When the specific weight of the liquid is 62.3 pounds per cubic foot , which is the value for water at a standard temperature of 68 F, then: 0

\-....../

15

HI Centrifugal Pump Tests P...

w

2000

= 旦旦

3960

If the pump is handling a liquid with different specific weight , or water at a temperature resulting in a specific weight per cubic foot other than 62.3 pounds , the above formula must be corrected so tha t: P-QH(S) w 3960

If pump output is measured in pounds per square inch , the formula for output power, regardless of the specific weight of the liquid , becomes: P=QAP w 1710

In order to maintain hydraulic similarity with the field operation , the following relationships are used for determining the head , rate of flow, power and NPSHR at the rated poin t. These relationships which follow definite rules are known as the affinity laws. The power relationship is based on the criteria that the efficiency stays constant with change in speed.

100 η p = ~wx P p

=

(::f

333 =

(泛注~f5

Where:

01

-

rate of flow on test;

O2 -

rate of flow on installation;

n1

-

speed on test in rpm;

n2

-

一

speed on installation in rpm; head on test;

H2

-

head on installation;

P1

-

power on test;

1.6.5.8.6 Calculation of efficiency The pump efficiency expressed in percent is calculated by:

三= (~:r.5

01 O2

/-\

叫

/月四\ /

The overall efficiency of a motor-driven unit expressed in percent is calculated by:

P\

ηOA=(FL)1OO or;ηOA =ηpX 站t f

\ mot/

P2

-

power on installation;

NPSHR1 = NPSH on test; NPSHR2 = NPSH on installation.

1.6.5.8.7 Plotting performance test results The total head , efficiency and power input are usually plotted as ordinates on the same sheet with rate of flow as the abscissa , as shown on Figure 1.118.

之|間!ET|d

1.6.5.8.8 Performance test at other than rated speed Test of a full-sized pump at reduced

16

是」

UET

已治~ 豆

EmclemIY

•志ñ、

v

EEL

/

Power(s= 1 日 r)r

、\

\

」戶，

1----""

」戶，

v

一17

/

弋

/

/

z

L..----""" 戶「

NPSHR

1/

I I

-

L..----"""

Rate offlow

Figure 1.118 - Pump pe斤。 rmance (all data is corrected to rated speed)

正工ω且Z

In tests at reduced speed , the relative power loss in bearing and stuffing-box friction may be increased , an effect which may be appreciable in small pumps. The hydraulic friction losses may be relatively increased when the Reynolds number for the water passages is reduced , an e仟ect which may be appreciable in small pumps of low specific speed. Therefore , these factors must be considered in determining an acceptable test speed.

、

戶均 h\ τz g3

1.6.5.8.8.1 speed

SPEED-RPM Denotes head- rate olllow kfor w|hich pump was sold 』\

HI Centrifugal Pump Tests -

Peñormance test correction to rated

For purposes of plotting , the rate of flow, head and power shall be corrected from the test values at test speed to the rated speed of the pump. The corrections are made as follows:

Ra悟 of flow: Head:

H

'l

色

=

O2 =

[去]Q1

rn 司 l2 I 二 I H. Ln

1J

m

=叫~:] =ω8[誨]

=

75.5 枷

slnce:

叫

一 n 2 (02)0.5 H歹5""

-

3550(90.8)。 5=1420 68.50.75

then ,

γ he

-nT(Q1)。 5=2950(75.5)05=1420 H歹75

47.3 0

NPSH to be used in the factory test is:

NP叫 = NPSH2 [之r

=

8[誨r

=

5.5 m

Example (US Units): A pump for 400 gpm , 225 feet total head and 26.1 ft NPSHA running at 3550 rpm is to be tested at 2950 rpm. What head , rate of flow and NPSHA should be used in the factory test? Applying the relationships given above , the head per stage to be used in the factory test is:

叫=叫去了=叫:第r = 155 位 The rate of flow to be used in the factory test is:

﹒

rn l3 P2 = I 前 I P1 'l

Input power:

門J

1.6.5.8.8.3 speed

一一

01

叫

\--..-/

7

The rate of flow to be used in the factory test is:

1.6.5.8.8.2 Peñormance test of full-sized pumps at increased speed Under unusual circumstances , it may be desirable to carry out tests at higher speeds than specified for the installation. This may be due to the limitations of available prime movers or correct electrical frequency. In this case , if such tests do not exceed safe operating limits of the pump , all of the above considerations continue to apply.

,

A『

Eddy current losses , EC 1, are normally measured by manufacturers during development studies. Values from these tests may be used in lieu of measurements during the contractural performance tes t.

」

Eddy current losses on test in kW (bhp).

nu-nU FO=b III-l

EC 1 =

月4 「

Power on installation in kW (bhp);

「Ill-L

P2 =

-- no0o5

Q 三 Fb 呵， ιZJ

Power on test in kW (bhp);

「lIlli--

P1 =

qJh

門4

d;

(P 1 - EC 1)(n2/n1)3 + EC 1(n2/n

H

「Il-- 」

=

H

一-

P2

Applying the relationships given above , the head per stage to be used in the factory test is:

叫一~

\、、

Sealless pumps incur significant eddy current losses which are affected by speed. Impeller input power varies approximately with the cube of rpm as they do in conventionally sealed pumps. Eddy current losses are propo付 ional to rpm squared. Therefore the following power correction for speed is made:

2000

Example (Metric): A pump for 90.8 m3/h , 68.5 meters , total head and 8 m NPSHA running at 3550 rpm is to be tested at 2950 rpm. What head , rate of flow and NPSHA should be used in the factory test?

01 =

02[之]

=

4叫::這]

= 332

slnce:

N-n2(Q2)。 5-3550(400)0.5=1220 叫一可.75

一

部 0.75

、、 )

17

HI Centrifugal Pump Tests -

2000 llot =

then

N-n1(Q1)。 5z2950(332)0.5=1220 叫 -1TT

叫 0.75

=

= 18ft

This will keep the specific speeds the same in the facto叩 test as in the field installation. 1.6.5.8.9 Performance test correction for temperature variations

Exponent to be established by manufacturer's data (probably in the range of 0.01 toO.1).

Example: (Metric) Typical efficiency adjustment for increased temperature. A test on water at 37.8 0 C resulted in an efficiency of 80%. What will be the probable efficiency at 1770 C? η ot

IV _"\X

=

/干Lm

\ll/•• o-885

4tnu

..

llot = .826 = 82.6%

Example: (US units) Typical efficiency adjustment for increased temperature. A test on water at 1000 F resulted in an efficiency of 80%. What will be the probable efficiency at 350 0 F? η ot = 1 一 (1

IV_"\X

r. 00000185 ,\ 0.1

川= 1 一 (1 一 .80)1 一一一一一 l .- -'\.

.0000076 )

llot = 1 一 (0.2)(.868) ,

reduce hydraulic skin friction or flow losses.

llot = .826 = 82.6%

1.6.5.8.10 Performance test correction for specific weight variations If the test is run with a liquid of different specific weight from that of the field installation , there will be a revision in required input power which will be determined as follows:

1 一 (1 叫)(如x (PP'2 n)"

Where:

y2

= (P X一 n ) , "y1 ,. P'1

There is no change in Efficiency at test temperature , decimal value;

/-\

叫)1 如

reduce disc friction losses;

The net e仟'ect of a reduction in viscosity due to higher temperature will depend on specific speed and on the design details of the pump. Where substantiating data are availab峙， performance data from a cold water test may be adjusted to hot water operating conditions on the basis of the following formula:

nu “

,

、

、BF

、

..

-n/-

自一『'' 、/ ，

4

Fhd 只U

nO/1

a 司 ••

'， 1 、'，

••

一一

tt oo

or

18

1 一 (1η t)l ~L)

4 司

increase the internal leakage losses;

x =

一一一一

Reduced viscosity of water at increased temperature will have an influence on efficiency. For pumps in the lower range of specific speed typically below 1750 (1500) , such as high pressu 舟， multi-stage boiler feed pumps and large , single-stage hot water circulating pumps , reduced viscosity will:

Kinematic viscosity at test temperature , mm 2/s;

吶UE

Any reduction in specific weight, as caused by an increase in temperature , results in a directly proportional reduction in output and input power; therefore , the efficiency is not changed.

η=

、

Kinemati