This standard is drafted in accordance with the rules given in GB/T 1.1-2009.
This standard replaces GB/T 3216-2005 Rotodynamic Pumps — Hydraulic Performance Acceptance Tests — Grades 1 and 2.
In addition to a number of editorial changes, the following technical deviations have been made with respect to GB/T 3216-2005:
— the standard name is modified (see cover hereof; cover of Edition 2005);
— the introduction is modified (see introduction; introduction of Edition 2005);
— the levels of acceptance are modified (see Clause 1; Clause 1 of Edition 2005);
— the normative references are modified (see Clause 2; Clause 2 of Edition 2005);
— the terms, definitions, symbols and subscripts are modified (see Clause 3; Clause 3 of Edition 2005);
— the instruction for tolerance grades given in Table 8 include manufacturing and measurement tolerance is added (see 4.1);
— the guaranteed objects are modified (see 4.2; 4.1 of Edition 2005);
— the amplitude of fluctuations of temperature, inlet and outlet head are modified (see Table 3);
— the provisions of unstable conditions and the variation limits between repeated measurements of the same quantity have been deleted (see 5.4.2.3.2 and Table 4 of Edition 2005);
— the calculation formula of random uncertainty eR and the value of t-distribution are added (see 4.3.3.1 and Table 4);
— The measured quantity of systematic uncertainty are modified (see Table 5; Table 7 of Edition 2005);
— the grades of overall uncertainties are added (see Table 6);
— the tolerances for evaluation of flow, head and efficiency are modified (see 4.4; 6.3 and 6.4 of Edition 2005);
— the evaluation of guaranteed efficiency is added (see 4.4.4);
— the performance test acceptance grades and corresponding tolerance are modified (see Table 8; Table 10 of Edition 2005);
— the default test acceptance grades are added (see 4.5 and Table 9);
— the requirements for test points for all performance tests are modified (see 5.7.1; 5.4.1 of Edition 2005);
— the test personnel is deleted (see 5.2.4 of Edition 2005);
— the feature of "clean cold water” is deleted (see 5.4.5.2 of Edition 2005);
— the feature of the test liquid may be replaced by clean cold water is deleted (see 5.4.5.3 of Edition 2005);
— the requirements for tolerance factor for NPSHR are modified (see 5.8.2.5; 11.3.3 of Edition 2005);
— the determination of reduction of impeller diameter is modified (see 6.2.1; Annex D of Edition 2005);
— the measurement of flow rate is modified (see D.3, Annex D; Clause 7 of Edition 2005);
— the “Tests performed on the entire equipment set — String test” is added (see Annex E).
— the “Special test methods” is added (see Annex G);
— the “Witnessed pump test” is added (see Annex H);
— the “Measurement uncertainty for NPSH test” is added (see Annex J);
— the “Friction losses” is deleted, and the content of the original “Table E.1 Equivalent uniform roughness k for pipes” is moved to “A.4.9 Friction losses at inlet and outlet” (see Annex E of Edition 2005);
— the “Costs and repetition of tests” is deleted (see Annex H of Edition 2005);
— the “Performance correction chart for viscous liquids” is deleted (see Annex I of Edition 2005);
— the “NPSHR reduction for pumps handling hydrocarbon liquids and high temperature water” is deleted (see Annex J of Edition 2005);
— the “Statistical evaluation of measurement results” is deleted (see Annex K of Edition 2005);
— the “Pump test sheet” is deleted (see Annex M of Edition 2005);
This standard is identical with International Standard ISO 9906:2012 Rotodynamic Pumps — Hydraulic Performance Acceptance Tests — Grades 1, 2 and 3.
For the purposes of this standard, the following editorial changes have also been made with respect to the ISO 9906:2012:
— according to Chinese usage, the rotational speed unit "r/min" is added (see Table 1);
— the power and efficiency tolerance curves in Figures 5 and 6 are modified, and the original ISO text is incorrect;
— the key in Figure A.1 has been deleted, and the original ISO text is incorrect.
This standard was proposed by the China Machinery Industry Federation.
This standard is under the jurisdiction of National Technical Committee 211 on Pumps of Standardization Administration of China (SAC/TC 211).
The previous editions of this standard are as follows:
— GB 3216-1982, GB/T 3216-1989, GB/T 3216-2005.
?
Introduction
The tests in this standard are intended to ascertain the performance of the pump and to compare this with the manufacturer’s guarantee.
The nominated guarantee for any quantity is deemed to have been met if, where tested according to this standard, the measured performance falls within the tolerance specified for the particular quantity (see 4.4).
Rotodynamic Pumps — Hydraulic Performance Acceptance Tests — Grades 1, 2 and 3
1 Scope
This standard specifies hydraulic performance tests for customers’ acceptance of rotodynamic pumps (centrifugal, mixed flow and axial pumps, hereinafter “pumps”).
This standard is intended to be used for pump acceptance testing at pump test facilities, such as manufacturers’ pump test facilities or laboratories.
It can be applied to pumps of any size and to any pumped liquids which behave as clean, cold water. This standard specifies three levels of acceptance:
— grades 1B, 1E and 1U with tighter tolerance;
— grades 2B and 2U with broader tolerance;
— grade 3B with even broader tolerance.
This standard applies either to a pump itself without any fittings or to a combination of a pump associated with all or part of its upstream and/or downstream fittings.
2 Normative References
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 17769-1 Liquid Pumps and Installation — General Terms, Definitions, Quantities, Letter Symbols and Units — Part 1: Liquid Pumps
ISO 17769-2 Liquid Pumps and Installation — General Terms, Definitions, Quantities, Letter Symbols and Units — Part 2: Pumping System
3 Terms, Definitions, Symbols and Subscripts
3.1 Terms and definitions
For the purposes of this document, the terms, definitions, quantities and symbols given in ISO 17769-1 and 17769-2 and the following apply.
Note 1: Table 1 gives an alphabetical list of the symbols used and Table 2 gives a list of subscripts; see 3.3.
Note 2: All formulae are given in coherent SI units. For conversion of other units to SI units, see Annex I.
3.1.1 General terms
Note: All of the types of test in 3.1.1 apply to guarantee point to fulfil the customer’s specification(s).
3.1.1.1
guarantee point
flow/head (Q/H) point, which a tested pump shall meet, within the tolerances of the agreed acceptance class
3.1.1.2
factory performance test
pump test performed to verify the initial performance of new pumps as well as checking for repeatability of production units, accuracy of impeller trim calculations, performance with special materials, etc.
Note: A typical performance test consists of the measurement of flow, head and power input to the pump or pump test motor. Additional measurements, such as NPSH, may be included as agreed upon. A factory test is understood to mean testing at a dedicated test facility, often at a pump manufacturer’s plant or at an independent pump test facility.
3.1.1.3
non-witnessed pump test
3.1.1.3.1
factory test
test performed without the presence of a purchaser’s representative, in which the pump manufacturer is responsible for the data collection and judgement of pump acceptance
Note: The advantage of this test is cost savings and accelerated pump delivery to the pump user. In many cases, if the purchaser is familiar with the performance of the pump (e.g. identical pump model order), a factory non-witnessed test may be acceptable.
3.1.1.3.2
signed factory test
test performed without the presence of a purchaser’s representative, in which the pump manufacturer is responsible for compliance with the parameters of the agreed acceptance class
Note: The pump manufacturer conducts the test, passes judgement of pump acceptance and produces a signed pump test document. The advantage of this test is the same as seen on the non-witnessed test. Compared to a witnessed test, this test is substantially less expensive and often leads to accelerated pump delivery to the end user.
?
3.1.1.4
witnessed pump test
Note: The witnessing of a pump test by a representative of the pump purchaser can serve many useful functions. There are various ways of witnessing a test.
3.1.1.4.1
witnessing by the purchaser’s representative
testing physically attended by a representative of the purchaser, who signs off on the raw test data to certify that the test is performed satisfactorily
Note: It is possible for final acceptance of the pump performance to be determined by the witness. The benefit of witness testing depends largely on the effectiveness and expertise of the witness. A witness cannot only ensure the test is conducted properly, but also observes operation of the pump during testing prior to pump shipment to the job site. A disadvantage of witness testing can be extended delivery times and excessive cost. With just-in-time manufacturing methods, the scheduling of witness testing requires flexibility on the part of the witness and can lead to additional costs if the schedule of the witness causes delays in manufacturing.
3.1.1.4.2
remote witnessing by the purchaser’s representative
pump performance testing witnessed from a distance by the purchaser or his/her representative
Note: With a remote camera system, the purchaser can monitor the entire testing remotely in real-time. The raw data, as recorded by the data acquisition system, can be viewed and analysed during the test, and the results can be discussed and submitted for approval. The advantages of this type of testing are savings in travel costs and accelerated pump delivery.
3.2 Terms relating to quantities
3.2.1
angular velocity
w
number of radians of shaft rotation
Note 1: It is given by:
w = 2πn (1)
Note 2: It is expressed in time, e.g. s-1, where n is given in 60 × min-1.
3.2.2
speed of rotation
number of rotations per second
3.2.3
mass flow rate
rate of flow discharged into the pipe from the outlet connection of the pump
Note 1: The mass flow rate is given in kilograms per second.
Note 2: The following losses or limiting effects are inherent to the pump:
a) discharge necessary for hydraulic balancing of axial thrust;
b) cooling of the pump bearings.
Note 3: Leakage from the fittings, internal leakage, etc., are not to be reckoned in the rate of flow. On the contrary, all derived flows for other purposes, such as
a) cooling of the motor bearings, and
b) cooling of a gear box (bearings, oil cooler) are to be reckoned in the rate of flow.
Note 4: Whether and how these flows should be taken into account depends on the location of their derivation and of the section of flow-measurement respectively.
3.2.4
volume rate of flow
rate of flow at the outlet of the pump, given by:
(2)
Note: In this standard, this symbol may also designate the volume rate of flow in any given section. It is the quotient of the mass rate of flow in this section by the density. (The section may be designated by subscripts.)
3.2.5
mean velocity
mean value of the axial speed of flow, given by:
(3)
Note: Attention is drawn to the fact that in this case, Q may vary for different reasons across the circuit.
3.2.6
local velocity
speed of flow at any given point
3.2.7
head
energy of mass of liquid, divided by acceleration due to gravity, g, given by:
(4)
See 3.2.16.
3.2.8
reference plane
any horizontal plane used as a datum for height measurement
Note: For practical reasons, it is preferable not to specify an imaginary reference plane.
?
3.2.9
height above reference plane
height of the considered point above the reference plane
See Figure A.1.
Note: Its value is:
— positive, if the considered point is above the reference plane;
— negative, if the considered point is below the reference plane.
3.2.10
gauge pressure
pressure relative to atmospheric pressure
Note 1: Its value is:
— positive, if this pressure is greater than the atmospheric pressure;
— negative, if this pressure is less than the atmospheric pressure.
Note 2: All pressures in this standard are gauge pressures read from a manometer or similar pressure sensing instrument, except atmospheric pressure and the vapour pressure of the liquid, which are expressed as absolute pressures.
3.2.11
velocity head
kinetic energy of the liquid in movement, divided by gravitational acceleration g, given by:
(5)
3.2.12
total head
overall energy in any section
Note 1: The total head is given by:
(6)
where
z is the height of the centre of the cross-section above the reference plane;
p is the gauge pressure related to the centre of the cross-section.
Note 2: The absolute total head in any section is given by:
(7)
3.2.13
inlet total head
overall energy at the inlet section of the pump
Note: Inlet total head is given by:
(8)
3.2.14
outlet total head
overall energy at the outlet section of the pump
Note: Outlet total head is given by:
(9)
3.2.15
pump total head
algebraic difference between the outlet total head and the inlet total head
Note 1: If compressibility is negligible, H = H2 - H1. If the compressibility of the pumped liquid is significant, the density, ρ, should be replaced by the mean value:
(10)
and the pump total head should be calculated by Formula (11):
(11)
Note 2: The correct mathematical symbol is H1-2.
3.2.16
specific energy
energy of liquid, given by:
y = gH (12)
3.2.17
loss of head at inlet
difference between the total head of the liquid at the measuring point and the total head of the liquid in the inlet section of the pump
3.2.18
loss of head at outlet
difference between the total head of the liquid in the outlet section of the pump and the total head of the liquid at the measuring point
3.2.19
pipe friction loss coefficient
coefficient for the head loss by friction in the pipe
3.2.20
net positive suction head NPSH
absolute inlet total head above the head equivalent to the vapour pressure relative to the NPSH datum plane
Note 1: NPSH is given by:
(13)
Note 2: This NPSH relates to the NPSH datum plane, whereas inlet total head relates to the reference plane.
Note 3: A derogation has been given to allow the use of the abbreviated term NPSH (upright and not bold) as a symbol in mathematical formulae as a consequence of its well-established, historical use in this manner.
3.2.20.1
NPSH datum plane
horizontal plane through the centre of the circle described by the external points of the entrance edges of the impeller blades
3.2.20.2
NPSH datum plane
plane through the higher centre
See Figure 1.
Note: It is the responsibility of the manufacturer to indicate the position of this plane with respect to precise reference points on the pump.
Key
1 — NPSH datum plane
Figure 1 — NPSH datum plane
3.2.21
available NPSH
NPSHA
NPSH available as determined by the conditions of the installation for a specified rate of flow
Note: A derogation has been given to allow the use of the abbreviated term NPSHA (upright and not bold) as a symbol in mathematical formulae as a consequence of its well-established, historical use in this manner.
?
3.2.22
required NPSH
NPSHR
minimum NPSH given by the manufacturer for a pump achieving a specified performance at the specified rate of flow, speed and pumped liquid (occurrence of visible cavitation, increase of noise and vibration due to cavitation, beginning of head or efficiency drop, head or efficiency drop of a given amount, limitation of cavitation erosion)
Note: A derogation has been given to allow the use of the abbreviated term NPSHR (upright and not bold) as a symbol in mathematical formulae as a consequence of its well-established, historical use in this manner.
3.2.23
NPSH3
NPSH required for a drop of 3% of the total head of the first stage of the pump as standard basis for use in performance curves
Note: A derogation has been given to allow the use of the abbreviated term NPSH (upright and not bold) as a symbol in mathematical formulae as a consequence of its well-established, historical use in this manner.
3.2.24
type number
dimensionless quantity calculated at the point of best efficiency
Note 1: It is given by:
(14)
where
Q′ is the volume rate of flow per eye;
H′ is the head of the first stage;
n is given in s-1.
Note 2: The type number is to be taken at maximum diameter of the first stage impeller.
3.2.25
pump power input
P2
power transmitted to the pump by its driver
3.2.26
pump power output
hydraulic power at the pump discharge
Note: Pump power output is given by:
Ph = ρQgH = ρQy (15)
?
3.2.27
driver power input
Pgr
power absorbed by the pump driver
3.2.28
maximum shaft power
P2,max
maximum pump shaft power, as set by the manufacturer, which is adequate to drive the pump over the specified operating conditions
3.2.29
pump efficiency
pump power output divided by the pump power input
Note: Pump efficiency is given by:
(16)
3.2.30
overall efficiency
pump power output divided by the driver power input
Note: Overall efficiency is given by:
(17)
3.3 Symbols and subscripts
?
Table 1 Alphabetical list of basic letters used as symbols
Symbol Quantity Unit
A Area m2
D Diameter m
e Overall uncertainty, relative value %
f Frequency s-1, Hz
g Acceleration due to gravity a m/s2
H Pump total head m
HJ Losses in terms of head of liquid m
k Equivalent uniform roughness m
K Type number Pure number
l Length m
M Torque Nm
n Speed of rotation r/min, s-1, min-1
NPSH Net positive suction head m
p Pressure Pa
P Power W
q Mass flow rate b kg/s
Q (Volume) rate of flow c m3/s
Re Reynolds number Pure number
τ Tolerance factor, relative value %
t Students distribution Pure number
U Mean velocity m/s
v Local velocity m/s
V Volume m3
y Specific energy J/kg
z Height above reference plane m
zD Difference between NPSH datum plane and reference plane (see 3.2.20) m
h Efficiency %
θ Temperature °C
l Pipe friction loss coefficient Pure number
u Kinematic viscosity m2/s
ρ Density kg/m3
w Angular velocity rad/s
a In principle, the local value of g should be used. Nevertheless, for grades 2 and 3, it is sufficient to use a value of g = 9.81 m/s2. For the calculation of the local value g = 9.7803(1+0.0053sin2j)-3×10-6Z, where j is the latitude and Z is the height above sea level.
b An optional symbol for mass flow rate is qm.
c An optional symbol for volume rate of flow is qv.
?
Table 2 List of letters and figures used as subscripts
Subscript Meaning
1 inlet
1′ inlet measuring section
2 outlet (except for P2)
2′ outlet measuring section
abs absolute
amb ambient
D difference, datum
f liquid in measuring pipes
G guaranteed
H pump total head
h hydraulic
gr combined motor/pump unit (overall)
J losses
M manometer
n speed of rotation
p power
Q (volume) rate of flow
ref reference plane
sp specified
T translated, torque
v vapour (pressure)
h efficiency
x at any section
4 Pump Measurements and Acceptance Criteria
4.1 General
The specified and contractually agreed upon rated point (duty point), hereinafter “the guarantee point”, shall be evaluated against one acceptance grade and its corresponding tolerance. For a pump performance test, this guarantee point shall always specify the guaranteed flow, QG, and guaranteed head, HG, and may, optionally, specify guaranteed efficiency, guaranteed shaft power or guaranteed net positive suction head required (NPSHR). Where applicable, these optional guarantee parameters need to be specified for those tests, see respective tests in 4.4.3 and 5.8.
The acceptance grade tolerance applies to the guarantee point only. Other specified duty points, including their tolerances, shall be by separate agreement between the manufacturer and purchaser. If other specified duty points are agreed upon, but no tolerance is given for these points, the default acceptance level for these points shall be grade 3.
A guarantee point may be detailed in a written contract, a customer-specific pump performance curve or similar written and project specific documentation.
If not otherwise agreed upon between the manufacturer and the purchaser, the following shall apply.
a) The acceptance grade shall be in accordance with the grades given in Table 8.
b) Tests shall be carried out on the test stand of the manufacturer’s works with clean, cold water using the methods and test arrangements specified in this standard.
c) The pump performance shall be guaranteed between the pump’s inlet connection and outlet connection.
d) Pipe and fittings (bends, reducers and valves) outside of the pump are not a part of the guarantee.
The combination of manufacturing and measurement tolerances in practice necessitates the usage of tolerances on tested values. The tolerances given in Table 8 take into account both manufacturing and measurement tolerances.
The performance of a pump varies substantially with the nature of the liquid being pumped. Although it is not possible to give general rules whereby performance with clean, cold water can be used to predict performance with other liquids, it is desirable for the parties to agree on empirical rules to suit the particular circumstances. For further information, see ISO/TR 17766.
If a number of identical pumps are being purchased, the number of pumps to be tested shall be agreed between the purchaser and manufacturer.
Both the purchaser and manufacturer shall be entitled to witness the testing. If tests are not carried out at the manufacturer’s test stand, opportunity shall be allowed for verification of the pump installation and instrumentation adjustments by both parties.
4.2 Guarantees
The manufacturer guarantees that, for the guarantee point and at the rated speed (or in some cases frequency and voltage), the measured pump curve touches, or passes through a tolerance surrounding the guarantee point, as defined by the applicable acceptance grade (see Table 8 and Figures 2 and 3).
A guarantee point shall be defined by a guaranteed flow, QG, and a guaranteed head, HG.
In addition, one or more of the following quantities may be guaranteed at the specified conditions and at the rated speed:
a) as defined in 4.4.3 and Figures 4, 5 and 6,
1) the minimum pump efficiency, ηG, or the maximum pump input power, PG, or
2) in the case of a combined pump and motor unit, the minimum combined efficiency, ηgrG, or the maximum pump motor unit input power, PgrG.
b) the maximum NPSHR at the guarantee flow.
The maximum power input may be guaranteed for the guarantee point or for a range of points along the pump curve. This, however, can require larger tolerances to be agreed upon between the purchaser and manufacturer.
4.3 Measurement uncertainty
4.3.1 General
Every measurement is inevitably subject to some uncertainty, even if the measuring procedures and the instruments used, as well as the methods of analysis, fully comply with good practice and with the requirements of this standard.
The guidance and procedures described in 4.3.2 and 4.3.3 are intended to provide general information to the user, as well as practical procedures allowing the user to estimate measurement uncertainty with reasonable confidence in applying the testing in conformity with this standard.
Note: For comprehensive information on measurement uncertainty, see ISO/IEC Guide 99 and associated documents.
4.3.2 Fluctuations
Where the design or operation of a pump is such that fluctuations of great amplitude are present, measurements may be carried out by providing a damping device in the measuring instruments or their connecting lines, which is capable of reducing the amplitude of the fluctuations to within the values given in Table 3. A symmetrical and linear damping device shall be used, for example a capillary tube, which shall provide integration over at least one complete cycle of fluctuations.
?
Table 3 Permissible amplitude of fluctuation as a percentage of mean value of quantity being measured
Measured quantity Permissible amplitude of fluctuations
Grade 1
% Grade 2
% Grade 3
%
Rate of flow ±2 ±3 ±6
Differential head ±3 ±4 ±10
Outlet head ±2 ±3 ±6
Inlet head ±2 ±3 ±6
Input power ±2 ±3 ±6
Speed of rotation ±0.5 ±1 ±2
Torque ±2 ±3 ±6
Temperature 0.3°C 0.3°C 0.3°C
4.3.3 Statistical evaluation of overall measurement uncertainty
4.3.3.1 The estimate of the random component (random uncertainty)
The random component due either to the characteristics of the measuring system or to variations of the measured quantity or both appears directly as a scatter of the measurements. Unlike the systematic uncertainty, the random component can be reduced by increasing the number of measurements of the same quantity under the same conditions.
A set of readings not less than three (3) shall be taken at each test point. The random component, eR, shall be calculated as follows:
The estimate of the random component of measurement uncertainty is calculated from the mean and the standard deviation of the observations. For the uncertainty of the readings, replace x with the actual measurement readings of flow, Q, head, H, and power, P.
If n is the number of readings, the arithmetic mean, , of a set of repeated observations xi xi(i = 1…n) is:
(18)
The standard deviation, s, of these observations is given by:
(19)
The relative value of the uncertainty, eR, of the mean due to random effects is given by:
(20)
where t is a function of n as given in Table 4.
Note 1: If the value of the overall uncertainty, e, does not meet the criteria given in Table 7, the value of the random component, eR, of the measurement can be reduced by increasing the number of measurements of the same quantity under the same conditions.
Note 2: The random component, as defined in this standard, is classified as Type A uncertainty (see ISO/IEC Guide 99).
Table 4 Values of Student’s t-distribution (based on 95% confidence level)
n t n t
3 4.30 12 2.20
4 3.18 13 2.18
5 2.78 14 2.16
6 2.57 15 2.14
7 2.45 16 2.13
8 2.36 17 2.12
9 2.31 18 2.11
10 2.26 19 2.10
11 2.23 20 2.09
4.3.3.2 The estimate of the instrumental measurement uncertainty (systematic uncertainties)
After all known errors have been removed by zero adjustment, calibration, careful measurement of dimensions, proper installation, etc., there remains an uncertainty which never disappears. This uncertainty cannot be reduced by repeating the measurements if the same instrument and the same method of measurement are used.
The estimate of the systematic uncertainty of the uncertainty, eS, is in practice based on calibration traceable to international measurement standards. Permissible relative values for the systematic uncertainty in this standard are given in Table 5.
?
Table 5 Permissible relative values of the instrumental uncertainty, eS
Measured quantity Maximum permissible systematic uncertainty
(at guarantee point)
Grade 1
% Grades 2 and 3
%
Rate of flow ±1.5 ±2.5
Differential head ±1.0 ±2.5
Outlet head ±1.0 ±2.5
Inlet head ±1.0 ±2.5
Suction head for NPSH testing ±0.5a ±1.0
Driver power input ±1.0 ±2.0
Speed of rotation ±0.35 ±1.4
Torque ±0.9 ±2.0
a See Annex J for explanation.
4.3.3.3 The overall uncertainty
The value for overall uncertainty, e, is given by:
(21)
Permissible values of overall measurement uncertainties, e, are given in Table 6.
Note: The overall uncertainty, as defined in this standard, is equated with expanded measurement uncertainty (see ISO/IEC Guide 99).
Table 6 Permissible values of overall uncertainties
Quantity Symbol Grade 1
% Grades 2, 3
%
Flow rate eQ ±2.0 ±3.5
Speed of rotation en ±0.5 ±2.0
Torque eT ±1.4 ±3.0
Pump total head eH ±1.5 ±3.5
Driver power input ePgr ±1.5 ±3.5
Pump power input (computed from torque and speed of rotation) ep ±1.5 ±3.5
Pump power input (computed from driver power and motor efficiency) eP ±2.0 ±4.0
4.3.3.4 Determination of overall uncertainty of efficiency
The overall uncertainty of the overall efficiency and of the pump efficiency is calculated using Formulae (22), (24) and (25):
(22)
if efficiency is computed from torque and speed of rotation:
(23)
if efficiency is computed from pump power input:
(24)
Using the values given in Table 6, the calculations lead to the results given in Table 7.
Table 7 Resulting greatest values of the overall uncertainties of efficiency
Quantity Symbol Grade 1
% Grades 2 and 3
%
Overall efficiency (computed from Q, H, Pgr) eηgr ±2.9 ±6.1
Pump efficiency (computed from Q, H, M, n) eη ±2.9 ±6.1
Pump efficiency (computed from Q, H, Pgr, hmot) eη ±3.2 ±6.4
4.4 Performance test acceptance grades and tolerances
4.4.1 General
Six pump performance test acceptance grades, 1B, 1E, 1U, 2B, 2U and 3B are defined in this subclause. Grade 1 is the most stringent grade, with 1U and 2U having a unilateral tolerance and grades 1B, 2B and 3B having a bilateral tolerance. Grade 1E is also bilateral in nature and is important to those concerned with energy efficiency.
Note: The grades 1U, 1E and 1B have the same tolerance for flow and head.
The purchaser and manufacturer may agree to use any grade to judge whether or not a specific pump meets a guarantee point. If a guarantee point is given, but no acceptance grade is specified, this standard reverts to a default test acceptance grade, as described in 4.5.
Guarantee point acceptance grades for pump head, flow, power and efficiency are provided in Table 8. All tolerances are percentages of values guaranteed.
?
Table 8 Pump test acceptance grades and corresponding tolerance
Grade 1 2 3
Guarantee requirement
△τQ 10% 16% 18%
△τH 6% 10% 14%
Acceptance grade 1U 1E 1B 2B 2U 3B
τQ +10% ±5% ±8% +16% ±9% Mandatory
τH +6% ±3% ±5% +10% ±7%
τP +10% +4% +8% +16% +9% Optional
τη ≥0% -3% -5% -7%
Note: τx(x = Q, H, P, η) stands for the tolerance of the indicated quantity.
4.4.2 Tolerances for pumps with an input power of 10 kW and below
For pumps with shaft power input of below 10 kW, the tolerance factors given in Table 8 can be too stringent. If not otherwise agreed upon between the manufacturer and purchaser, the tolerance factors shall be the following:
— rate of flow τQ = ±10%;
— pump total head τH = ±8%.
The tolerance factor on efficiency, τη, if guaranteed, shall be calculated as given by Formula (25):
(25)
where the pump power input, P2, tallies with the maximum shaft power (input), P2,max, in kilowatts, over the range of operation. A tolerance factor, τP,gr ,is allowed using Formula (26):
(26)
4.4.3 Evaluation of flow and head
Guarantee point evaluation shall be performed at the rated speed. Test points do not have to be recalculated based on speed in cases where the test speed is identical to the rated speed and for tests with a combined motor and pump (i.e. submersible pumps, close-coupled pumps and all pumps tested with the motor which are installed with the pump). For tests in which the test speed is different from the rated speed, each test point shall be recalculated to the rated speed, using the affinity laws.
The tolerances for flow and head shall be applied in the following manner.
— The pump flow tolerance shall be applied to the guaranteed flow, QG, at the guaranteed head, HG;
— The pump head tolerance shall be applied to the guaranteed head, HG, at the guaranteed flow, QG.
Acceptance is achieved if either flow or head, or both, are found to be within the applicable tolerance (see Figures 2 and 3).
Key:
X — rate of flow, Q;
Y — head, H;
Curve 1: crosses the head tolerance, P = pass;
Curve 2: crosses the flow tolerance, P = pass;
Curve 3: crosses both the head and flow tolerance, P = pass;
Curve 4: does not cross any tolerance, F = fail;
Curve 5: does not cross any tolerance, F = fail;
Figure 2 Uni-lateral tolerance acceptance
Key:
X — rate of flow, Q;
Y — head, H;
curve 1: crosses the head tolerance, P = pass;
curve 2: crosses the flow tolerance, P = pass;
curve 3: crosses both the head and flow tolerance, P = pass;
curve 4: does not cross any tolerance, F = fail;
curve 5: does not cross any tolerance, F = fail;
Figure 3 Bi-lateral tolerance acceptance
4.4.4 Evaluation of efficiency or power
If efficiency or power has been guaranteed, it shall be evaluated against the applicable acceptance grade tolerance factor, i.e. the same as for Q/H in the following manner.
After a best-fit test curve (Q-H-/Q-η/ or Q-P-curves) is drawn and smoothly fitted through the measured test points, an additional straight line shall be drawn between the origin (0 rate of flow, 0 head) and the guarantee point (rate of flow/head). If necessary, this line shall be extended until it crosses the fitted test curve. The intersection between the smoothly fitted test curve and this straight line shall form the new rate of flow/head point, which is used for evaluation of efficiency or power. The measured input power or calculated efficiency at this point shall be compared against the guaranteed value and the applicable power or efficiency tolerance factors (see Figures 4, 5 and 6).
Note 1: The reason for using the “line from origin” method when evaluating the guaranteed efficiency or power is that it best retains the pump characteristics if the impeller diameter is changed. Additionally, this method always gives one single point of reference for evaluation.
Note 2: The tolerance limits for flow and head can be reduced as a result of adding a power guarantee.
Foreword II
Introduction V
1 Scope
2 Normative References
3 Terms, Definitions, Symbols and Subscripts
3.1 Terms and definitions
3.2 Terms relating to quantities
3.3 Symbols and subscripts
4 Pump Measurements and Acceptance Criteria
4.1 General
4.2 Guarantees
4.3 Measurement uncertainty
4.4 Performance test acceptance grades and tolerances
4.5 Default test acceptance grades for pump application
5 Test Procedures
5.1 General
5.2 Date of testing
5.3 Test programme
5.4 Testing equipment
5.5 Records and report
5.6 Test arrangements
5.7 Test conditions
5.8 NPSH tests
6 Analysis
6.1 Translation of the test results to the guarantee conditions
6.2 Obtaining specified characteristics
Annex A (Normative) Test Arrangements
Annex B (Informative) NPSH Test Arrangements
Annex C (Informative) Calibration Intervals
Annex D (Informative) Measurement Equipment
Annex E (Informative) Tests Performed on the Entire Equipment Set — String Test
Annex F (Informative) Reporting of Test Results
Annex G (Informative) Special Test Methods
Annex H (Informative) Witnessed Pump Test
Annex I (Informative) Conversion to SI Units
Annex J (Informative) Measurement Uncertainty for NPSH Test
Bibliography
回轉動力泵 水力性能驗收試驗
1級、2級和3級
1 范圍
本標準規定了回轉動力泵(離心泵、混流泵和軸流泵，以下簡稱“泵”)的水力性能驗收試驗方法。
本標準適用于在泵試驗基地進行的泵驗收試驗，例如實驗室或泵制造廠家試驗臺。
本標準適用于輸送符合清潔冷水性質液體的任何尺寸的泵。
本標準中規定了三種驗收等級：
——1B級、1E級和1U級，具有較嚴格的容差；
——2B級和2U級，具有較寬泛的容差；
——3B級，具有更寬泛的容差。
本標準既適用于不帶任何管路附件的泵本身，也適用于連接全部或部分上游和/或下游管路附件的泵組合體。
注：從泵分類上，旋渦泵也劃入回轉動力泵。
2 規范性引用文件
下列文件對于本文件的應用是必不可少的。凡是注日期的引用文件，僅注日期的版本適用于本文件。凡是不注日期的引用文件，其最新版本(包括所有的修改單)適用于本文件。
ISO 17769-1 液體泵及其裝置 通用術語、定義、量、字符和單位 第1部分：液體泵(Liquid pumps and installation—General terms ， definitions， quantities ，letter symbols and units—Part 1：Liquid pumps)
ISO 17769-2 液體泵及其裝置 通用術語 、定義、量、字符和單位 第2部分：泵輸送系統(Liquid pumps and installation—General terms， definitions， quantities， letter symbols and units—Part 2：Pumping system)
3 術語、定義、符號和腳標
3.1 術語和定義
ISO 17769-1和ISO 17769-2界定的以及下列術語、定義、量和符號適用于本文件。
注1：表1給出所用符號的字母表，表2給出腳標表，見3.3。
注2：所有公式均以SI單位給出。關于其他單位換算為SI單位，參見附錄I。
3.1.1 一般術語
注：為了滿足用戶的技術要求，3.1.1中所有的試驗類型適用于保證點。
3.1.1.1
保證點 guarantee point
在各方同意的驗收等級的容差范圍內，被試驗的泵應滿足的流量/揚程(Q/H)點。
3.1.1.2
出廠性能試驗 factory performance test
為了驗證新泵的初始性能以及檢查生產機組的重復性、葉輪修正計算的準確性、特殊材料的性能等所進行的泵試驗。
注：典型的性能試驗包括流量、揚程、泵或泵試驗電機的輸入功率的測量。在各方同意的基礎上，可包括例如汽蝕余量(NPSH)的附加測量。出廠試驗可理解為在一個專用的試驗臺進行的試驗，通常是在泵制造廠家的工廠或一個獨立的泵試驗基地進行。
3.1.1.3 泵的非見證試驗
3.1.1.3.1
出廠試驗 factory test
在買方代理人不出席的情況下進行的試驗，試驗中泵制造廠家應對收集的數據和泵驗收的判定負責。
注：本試驗的優點是節約成本并可加快給泵用戶的發貨速度。在多數情況下，如果買方了解泵的性能(例如同模型級泵相同) ，可進行非見證出廠試驗。
3.1.1.3.2
簽署出廠試驗 signed factory test
在買方代理人不出席的情況下進行的試驗，試驗中泵制造廠家應對所依據的、各方同意的驗收等級的參數負責。
注：泵制造廠家進行試驗，對泵驗收結果進行判斷，并編制和簽署一份泵試驗文件。本試驗的優點和出廠試驗相同。與見證試驗相比，本試驗的費用相對較低并通常可加快給終端用戶的發貨速度。
3.1.1.4 泵的見證試驗
注：泵買方代理人見證泵試驗，能起到很多有意義的作用。見證試驗有多種方式。
3.1.1.4.1
買方代理人見證 witnessing by the purchaser's representative
買方代理人出席的試驗，并在原始試驗數據上簽字，以證實試驗成功完成。
注：泵性能的最后驗收有可能通過見證人進行確定。見證試驗的效果很大程度上取決于見證人的專業經驗和能力。見證人不僅能保證試驗正確地進行，還可以在泵發往工作現場之前觀測試驗期間泵的運行情況。見證試驗的缺點是發貨時間拖延并且成本過高。在采用實時生產系統下，如果見證的進度安排導致生產拖延則會造成成本增加，因而要求見證試驗的進度安排在見證這一階段具有靈活性。
3.1.1.4.2
買方代理人遠程見證 remote witnessing by the purchaser's representative
買方或其代理人在一段距離內進行的泵性能試驗的見證。
注：買方可采用遠程攝像系統實時遠程監控整個試驗。買方在試驗期間可以審核和分析通過數據采集系統記錄的原始數據，并對結果進行討論和提交，以待審批。該試驗類型可以節省旅差費用并加快發貨速度。
3.2 與量相關的術語
3.2.1
角速度 angular velocity
?
每單位時間內軸旋轉的弧度數。
注1：由式(1)給出：
?＝2πn (1)
注2：用時間表示，例如s－1，式中n用60×min－1形式給出。
3.2.2
轉速 speed of rotation
每單位時間內的轉數。
3.2.3
質量流量 mass flow rate
從泵的出口法蘭排出進入管路的流量。
注1：質量流量的單位用千克每秒(kg/s)表示。
注2：泵內部需用、損失或抽取的流量不計入流量：
a) 水力平衡軸向力所需的排量；
b) 冷卻泵自身軸承。
注3：連接管件的泄漏、內部泄漏等不計入流量。反之，所有供其他用途的分出流量均計入流量。如：
a) 冷卻電機軸承；
b) 冷卻齒輪箱(軸承、油冷卻器)等。
注4：這些流量是否需要計入以及如何計入分別取決于分出流量的位置和流量測量截面的位置。
3.2.4
體積流量 volume rate of flow
泵出口的體積流量，由式(2)給出：
(2)
注：本標準中，符號Q也可以表示任何給定截面處的體積流量。它是該截面處質量流量和密度的商(截面可以用腳標標示)。
3.2.5
平均速度 mean velocity
軸向流速的平均值，由式(3)給出：
(3)
注：注意在這種情況下由于沿回路的各種原因Q可能會變化。
3.2.6
局部速度 local velocity
任意給定點的流速。
3.2.7
水頭 head
每單位質量流體的能量除以重力加速度g，由式(4)給出：
(4)
見3.2.16。
3.2.8
基準面 reference plane
用作高度測量基準的任一水平面。
注：為了實用，最好不要規定虛設的基準面。
3.2.9
相對基準面的高度 height above reference plane
所研究的點相對基準面的高度。
見圖A.1。
注：其值：
——如果所研究的點在基準面之上，其值為正；
——如果所研究的點在基準面之下，其值為負。
3.2.10
表壓 gauge pressure
相對大氣壓力的壓力。
注1：其值：
——如果該壓力高于大氣壓力，其值為正；
——如果該壓力低于大氣壓力，其值為負。
注2：在本標準中，除了大氣壓力和液體的汽化壓力以絕對壓力表示外，所有的壓力均指從壓力計或類似的壓力指示儀表上讀出的表壓。
3.2.11
速度水頭 velocity head
每單位質量運動液體的動能除以2g，由式(5)給出。
(5)
3.2.12
總水頭 total head
任一截面處的總能量。
注1：總水頭由式(6)給出：
(6)
式中：
z——橫截面中心相對基準面的高度；
p——所述橫截面中心的表壓。
注2：任一截面處的絕對總水頭由式(7)給出：
(7)
3.2.13
入口總水頭 inlet total head
泵入口截面處的總能量。
注：入口總水頭由式(8)給出：
(8)
3.2.14
出口總水頭 outlet total head
泵出口截面處的總能量。
注：出口總水頭由式(9)給出：
(9)
3.2.15
揚程 pump total head
出口總水頭和入口總水頭的代數差。
注1：如果液體的壓縮性可忽略不計，則H＝H2－H1。如果泵輸送液體的壓縮性明顯，則密度ρ應用平均值替代：
(10)
揚程應用式(11)計算：
(11)
注2：數學上的恰當符號為H1－2。
3.2.16
比能 specific energy
每單位質量流體的能量，由式(12)給出：
y＝gH (12)
3.2.17
入口水頭損失 loss of head at inlet
測量點處液體的總水頭與泵入口截面處液體的總水頭之差。
3.2.18
出口水頭損失 loss of head at outlet
泵出口截面處液體的總水頭與測量點處液體的總水頭之差。
3.2.19
管路摩擦損失系數 pipe friction loss coefficient
由管路摩擦所致的水頭損失的系數。
3.2.20
汽蝕余量 net positive suction head
NPSH
相對NPSH基準面的入口絕對總水頭與汽化壓力水頭的差。
注1： NPSH由式(13)給出：
(13)
注2：此NPSH與NPSH基準面有關，而入口總水頭與基準面有關。
注3：由于縮寫NPSH(正體且不加粗)這種使用方式的完善性和長期性，允許其在數學公式中作為符號使用。
3.2.20.1
NPSH基準面 NPSH datum plane
〈多級泵〉通過由葉輪葉片進口邊最外點所描繪的圓的中心的水平面。
3.2.20.2
NPSH基準面 NPSH datum plane
〈立軸或斜軸雙吸泵〉通過較高中心的平面。
見圖1。
注：制造廠家根據泵上準確的基準點負責指示出該平面的位置。
說明：
1——NPSH基準面。
圖1 NPSH基準面
3.2.21
有效汽蝕余量 available NPSH
NPSHA
由裝置條件確定的、規定流量下可獲得的(可利用的)NPSH。
注：由于縮寫NPSHA(正體且不加粗)這種使用方式的完善性和長期性，允許其在數學公式中作為符號使用。
3.2.22
必需汽蝕余量 required NPSH
NPSHR
在規定的流量、轉速和輸送液體的條件下，泵達到規定性能的最小汽蝕余量(出現可見汽蝕、汽蝕引起的噪聲和振動的增大、揚程或效率開始下降、給定降幅的揚程或效率、汽蝕侵蝕限度)，其值由制造廠家給出。
注：由于縮寫NPSHR(正體且不加粗)這種使用方式的完善性和長期性，允許其在數學公式中作為符號使用。
3.2.23
NPSH3
泵第一級揚程下降3％時的必需汽蝕余量，作為標準基準用于表示性能曲線。
注：由于縮寫NPSH(正體且不加粗)這種使用方式的完善性和長期性，允許其在數學公式中作為符號使用。
3.2.24
型式數 type number
按最佳效率點計算的無因次的量。
注1：由式(14)給出：
(14)
式中：
Q′——每一吸入口的體積流量；
H′——第一級揚程；
n用s－1表示。
注2：應按第一級葉輪的最大直徑取型式數。
3.2.25
泵輸入功率 pump power input
P2
驅動機傳輸給泵的功率。
3.2.26
泵輸出功率 pump power output
泵出口液體的有效功率。
注：泵輸出功率由式(15)給出：
Ph＝ρQgH＝ρQy (15)
3.2.27
驅動機輸入功率 driver power input
Pgr
泵驅動機吸收的功率。
3.2.28
泵最大輸入功率 maximum shaft power
P2，max
由制造廠家設定的、在規定運行條件下能正常驅動泵的最大輸入功率。
3.2.29
泵效率 pump efficiency
泵輸出功率除以泵輸入功率。
注：泵效率由式(16)給出：
(16)
3.2.30
總效率 overall efficiency
泵輸出功率除以驅動機輸入功率。
注：總效率由式(17)給出：
(17)
3.3 符號和腳標
表1 用作符號的基本字母表(按字母順序排列)
符號 量 單位
A 面積 m2
D 直徑 m
e 總的不確定度，相對值 ％
f 頻率 s－1，Hz
g 重力加速度a m/s2
H 揚程 m
HJ 液體水頭損失 m
k 當量均勻粗糙度 m
K 型式數 純數值
l 長度 m
M 轉矩 Nm
n 轉速 r/min，s－1，min－1
NPSH 汽蝕余量 m
p 壓力 Pa
P 功率 W
q 質量流量b kg/s
Q (體積)流量c m3/s
Re 雷諾數 純數值
τ 容差系數，相對值 ％
t t分布 純數值
U 平均速度 m/s
v 局部速度 m/s
V 體積 m3
y 比能 J/kg
z 相對基準面的高度 m
zD NPSH基準面(見3.2.20)與基準面位差 m
? 效率 ％
θ 溫度 ℃
? 管路摩擦損失系數 純數值
? 運動黏度 m2/s
ρ 密度 kg/m3
? 角速度 rad/s
a 原則上宜使用g的當地值。然而，對于2級和3級，g＝9.81 m/s2已足可滿足使用；
g的當地值計算公式為：g＝9.7803(1＋0.0053sin2?)－3×10－6Z，式中?為緯度，Z為海拔。
b 質量流量符號亦可選用qm。
c 體積流量符號亦可選用qv。
表2 用作腳標的字母和數字表
腳標 意義
1 入口
1′ 入口測量截面
2 出口(除P2外)
2′ 出口測量截面
abs 絕對的
amb 周圍的
D 差，基準
f 測量管流體
G 保證的
H 揚程
h 水力
gr 組合的電機/泵機組(總的)
J 損失
M 壓力計的
n 轉速
p 功率
Q (體積)流量
ref 基準面
sp 規定的
T 轉換的，轉矩
v 汽化(壓力)
? 效率
x 在任一截面
4 泵的測量和驗收準則
4.1 總則
規定的和合同中商定的規定點(工況點)，以下簡稱“保證點”，應通過一個驗收等級和其相對應的容差進行評價。對于泵的性能試驗，這個保證點通常應由保證流量QG和保證揚程HG加以確定，并且，也可選用保證效率、保證軸功率或保證必需汽蝕余量(NPSHR)加以確定。在適用的情況下，這些可選保證參數需要根據試驗進行確定，試驗要求分別見4.4.3和5.8。
驗收等級的容差僅適用于保證點。其他規定工況點，包括其容差在內，應經制造廠家和買方另外協商。如果有其他的規定工況點但沒有相對應容差的情況下，這些工況點的默認驗收等級應為3級。
可通過書面合同、客戶規定的泵性能曲線或類似書面的項目技術文件對保證點進行詳細說明。
如果制造廠家和買方之間沒有另外的商定，則下列條件適用：
a) 驗收等級應與表8中所給的等級一致；
b) 試驗應在清潔冷水條件下、采用本標準規定的試驗方法和試驗裝置、且在制造廠家的試驗臺上進行；
c) 泵入口和出口之間的性能應予以保證；
d) 泵外端的管路和配件(彎頭、變徑管、閥)不在保證范圍內。
實際上，測量值里的容差結合了制造容差和測量容差。表8中給出的容差系數值包括了制造容差和測量容差。
泵的性能可以隨輸送液體性質的不同而有顯著變化。雖然不可能給出一個普通適用的規則，使之可以用輸送清潔冷水時的性能預測輸送其他液體時的性能，但是商定一個適合特殊工況的經驗規則而泵仍用清潔冷水做試驗是可行的。詳見ISO/TR 17766。
如購買多臺同樣的泵，需要試驗的泵的數量應由買方和制造廠家進行商定。
買方和制造廠家雙方均有權要求見證這些試驗。如果試驗不在制造廠家的試驗臺上進行，應允許買方和制造廠家雙方有機會對泵的試驗裝置和儀器儀表及其校準狀態進行確認。
4.2 保證
制造廠家確保在保證點和規定轉速下(或在某些情況下是頻率和電壓)，測得的泵曲線與圍繞保證點的一個容差范圍內相切或通過，即根據適用的驗收等級確定(見表8、圖2和圖3)。
保證點應由保證流量QG和保證揚程HG加以確定。
此外，在規定的條件和規定的轉速下，下列諸量中的一個或多個可予以保證：
a) 如4.4.3和圖4、圖5和圖6中的規定；
1) 泵最低效率ηG，或泵的最大輸入功率PG；
2) 泵和電機作為一個機組的情況下，最小機組效率ηgrG，或最大機組輸入功率PgrG。
b) 保證流量下的最大必需汽蝕余量。
保證點下或泵曲線范圍內的最大輸入功率可以予以保證。然而，可能需要由買方和制造廠家商定大一些的容差范圍。
4.3 測量不確定度
4.3.1 總則
即使使用的測量方法、所用的儀表及分析方法完全可行并符合本標準的要求，每一測量量也仍不可避免地存在不確定度。
4.3.2和4.3.3中描述的導則和方法旨在給用戶提供一些資料性信息，以及一些實踐方法，用戶通過這些方法可對適用于本標準要求的試驗以合理的置信概率進行測量不確定度的評定。
注：關于測量不確定度的綜合性信息資料，見ISO/IEC Guide 99和相關文件。
4.3.2 波動
如果泵的設計或運轉使得測量數值出現大幅度的波動，則可以在測量儀表中或其連接管線中設置一種能使波動幅度降低到表3給定值范圍內的緩沖裝置來進行測量。緩沖裝置應是對稱和線性的，例如毛細管，它應提供至少是包含了一個完整的波動周期內的積分值。
表3 容許波動幅度，以測量量平均值的百分數表示
測量量 容許波動幅度
1級
％ 2級
％ 3級
％
流量 ±2 ±3 ±6
壓差 ±3 ±4 ±10
出口壓力 ±2 ±3 ±6
入口壓力 ±2 ±3 ±6
輸入功率 ±2 ±3 ±6
轉速 ±0.5 ±1 ±2
轉矩 ±2 ±3 ±6
溫度 0.3℃ 0.3℃ 0.3℃
4.3.3 總的測量不確定度的評定
4.3.3.1 隨機不確定度的評定
隨機不確定度，它或是由于測量系統的特征、或是由于被測量的量的變化、或是由于兩者共同所致，直接以測量結果的分散形式出現。與系統不確定度不同，隨機不確定度可以通過在同樣條件下增加同一量的測量次數來加以降低。
每一個試驗點應至少取3組讀數。隨機不確定度eR計算如下：
測量不確定度隨機部分的評定通過觀測值的平均值和標準偏差計算得出。對于讀數的不確定度，用流量Q，揚程H和功率P的實際測量讀數代替x。
如果n表示讀數的次數，那么一組重復測量觀測值xi(i＝1…n)的算術平均值 為：
(18)
這組觀測值的標準偏差s從式(19)導出：
(19)
隨機效應產生的平均值的相對不確定度值eR從式(20)導出：
(20)
式中：
t——表4中n的一個函數。
注1：如果總的不確定度值e不能滿足表7中的準則要求，那么測量的隨機不確定度值eR可以通過在同樣條件下增加同一量的測量次數來加以降低。
注2：本標準中規定的隨機部分屬于A類不確定度(見ISO/IEC Guide 99)。
表4 t分布數值(基于95％置信度)
4.3.3.2 系統不確定度的評定
當通過零點調整、校準、仔細地測量尺寸和正確地安裝等將已知的所有誤差均消除之后，仍然會留有不確定度，它永遠不會消失。即使仍使用同一儀表和同樣測量方法，也不能通過重復測量使其降低。
系統不確定度eS的評定實際上是以測量標準的校準為基礎。表5給出了系統不確定度的容許相對值。
表5 系統不確定度eS的容許相對值
測量量 最大容許系統不確定度(保證點)
1級
％ 2級和3級
％
流量 ±1.5 ±2.5
壓差 ±1.0 ±2.5
出口壓力 ±1.0 ±2.5
入口壓力 ±1.0 ±2.5
NPSH試驗的入口壓力 ±0.5a ±1.0
驅動機輸入功率 ±1.0 ±2.0
轉速 ±0.35 ±1.4
轉矩 ±0.9 ±2.0
a 解釋參見附錄J。
4.3.3.3 總體的不確定度
總體的不確定度值e從式(21)導出：
(21)
表6給出了總體的不確定度e的容許值。
注：本標準規定的總體不確定度等同于擴展測量不確定度(見ISO/IEC Guide 99)。
表6 總測量不確定度的容許值
量 符號 1級
％ 2級、3級
％
流量 eQ ±2.0 ±3.5
轉速 en ±0.5 ±2.0
轉矩 eT ±1.4 ±3.0
揚程 eH ±1.5 ±3.5
驅動機輸入功率 ePgr ±1.5 ±3.5
泵輸入功率(由轉矩和轉速計算得出) ep ±1.5 ±3.5
泵輸入功率(由驅動機輸入功率和電機效率計算得出) eP ±2.0 ±4.0
4.3.3.4 效率總體測量不確定度的評定
總效率和泵效率的總體測量不確定度按式(22)～式(24)計算：
(22)
如果效率由轉矩和轉速計算得出：
(23)
如果效率由泵輸入功率計算得出：
(24)
利用表6中給出的值進行計算即得出表7所給的結果。
表7 效率總體不確定度最大導出值
量 符號 1級
％ 2級和3級
％
總效率(由Q，H和Pgr計算得出) eηgr ±2.9 ±6.1
泵效率(由Q，H，M和n計算得出) eη ±2.9 ±6.1
泵效率(由Q，H，Pgr和ηmot計算得出) eη ±3.2 ±6.4
4.4 性能試驗驗收等級和容差系數值
4.4.1 總則
本標準中規定了6種泵性能試驗驗收等級，即1B、1E、1U、2B、2U和3B。1級要求最嚴格，其中1U級和2U級是單向容差，1B級、2B級和3B級是雙向容差。1E級在本質上也是雙向容差，并且在能效相關領域很重要。
注：對于流量和揚程，1U級、1E級和1B級具有相同的容差系數。
買方和制造廠家可在應用等級上進行協商，以判定一特定的泵是否滿足保證點的要求。如果給定一個保證點，但是沒有規定驗收等級，可以采用4.5中所述的默認試驗驗收等級。
表8中給出了泵揚程、流量、功率和效率的保證點驗收等級。所有的容差系數均以保證值的百分數表示。
表8 泵試驗驗收等級和相應的容差系數值
等級 1 3 保證要求
△τQ 10％ 16％ 18％
△τH 6％ 10％ 14％
驗收等級 1U 1E 1B 2B 2U 3B
τQ ＋10％ ±5％ ±8％ ＋16％ ±9％ 強制
τH ＋6％ ±3％ ±5％ ＋10％ ±7％
τP ＋10％ ＋4％ ＋8％ ＋16％ ＋9％ 可選
τη ≥0％ －3％ －5％ －7％
注：τx(x＝Q，H，P，η)代表指示數量的容差系數。
4.4.2 泵輸入功率不大于10 kW的泵的容差系數值
對于泵輸入功率不大于10 kW的泵，表8中給出的容差系數過于嚴格。如制造廠家和買方無另外商定，應使用下列容差系數：
——流量τQ＝±10％；
——揚程τH＝±8％。
效率的容差系數τη，在保證的情況下可用式(25)計算：
(25)
式中泵輸入功率P2為工作范圍內最大輸入功率，以kW表示。容差系數τPgr可用式(26)計算：
(26)
4.4.3 流量和揚程的評定
保證點的評定應在規定轉速下完成。當試驗轉速等同于規定轉速或電動機-泵合為一體的泵機組(例如潛沒式泵、共軸泵以及與電機連接且同步試驗的所有泵)的試驗時，不需要進行轉速換算。對于試驗轉速不同于規定轉速的試驗，每一試驗點應采用相似定律換算成規定轉速進行計算。
流量和揚程的容差適用于以下方式：
——泵流量容差適用于保證揚程HG下的保證流量QG；
——泵揚程容差適用于保證流量QG下的保證揚程HG。
如果流量或者揚程，或者兩者同時均在適用的容差(見圖2和圖3)范圍內，則滿足驗收要求。
