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
回转动力泵 水力性能验收试验
1级、2级和3级
1 范围
本标准规定了回转动力泵(离心泵、混流泵和轴流泵，以下简称“泵”)的水力性能验收试验方法。
本标准适用于在泵试验基地进行的泵验收试验，例如实验室或泵制造厂家试验台。
本标准适用于输送符合清洁冷水性质液体的任何尺寸的泵。
本标准中规定了三种验收等级：
——1B级、1E级和1U级，具有较严格的容差；
——2B级和2U级，具有较宽泛的容差；
——3B级，具有更宽泛的容差。
本标准既适用于不带任何管路附件的泵本身，也适用于连接全部或部分上游和/或下游管路附件的泵组合体。
注：从泵分类上，旋涡泵也划入回转动力泵。
2 规范性引用文件
下列文件对于本文件的应用是必不可少的。凡是注日期的引用文件，仅注日期的版本适用于本文件。凡是不注日期的引用文件，其最新版本(包括所有的修改单)适用于本文件。
ISO 17769-1 液体泵及其装置 通用术语、定义、量、字符和单位 第1部分：液体泵(Liquid pumps and installation—General terms ， definitions， quantities ，letter symbols and units—Part 1：Liquid pumps)
ISO 17769-2 液体泵及其装置 通用术语 、定义、量、字符和单位 第2部分：泵输送系统(Liquid pumps and installation—General terms， definitions， quantities， letter symbols and units—Part 2：Pumping system)
3 术语、定义、符号和脚标
3.1 术语和定义
ISO 17769-1和ISO 17769-2界定的以及下列术语、定义、量和符号适用于本文件。
注1：表1给出所用符号的字母表，表2给出脚标表，见3.3。
注2：所有公式均以SI单位给出。关于其他单位换算为SI单位，参见附录I。
3.1.1 一般术语
注：为了满足用户的技术要求，3.1.1中所有的试验类型适用于保证点。
3.1.1.1
保证点 guarantee point
在各方同意的验收等级的容差范围内，被试验的泵应满足的流量/扬程(Q/H)点。
3.1.1.2
出厂性能试验 factory performance test
为了验证新泵的初始性能以及检查生产机组的重复性、叶轮修正计算的准确性、特殊材料的性能等所进行的泵试验。
注：典型的性能试验包括流量、扬程、泵或泵试验电机的输入功率的测量。在各方同意的基础上，可包括例如汽蚀余量(NPSH)的附加测量。出厂试验可理解为在一个专用的试验台进行的试验，通常是在泵制造厂家的工厂或一个独立的泵试验基地进行。
3.1.1.3 泵的非见证试验
3.1.1.3.1
出厂试验 factory test
在买方代理人不出席的情况下进行的试验，试验中泵制造厂家应对收集的数据和泵验收的判定负责。
注：本试验的优点是节约成本并可加快给泵用户的发货速度。在多数情况下，如果买方了解泵的性能(例如同模型级泵相同) ，可进行非见证出厂试验。
3.1.1.3.2
签署出厂试验 signed factory test
在买方代理人不出席的情况下进行的试验，试验中泵制造厂家应对所依据的、各方同意的验收等级的参数负责。
注：泵制造厂家进行试验，对泵验收结果进行判断，并编制和签署一份泵试验文件。本试验的优点和出厂试验相同。与见证试验相比，本试验的费用相对较低并通常可加快给终端用户的发货速度。
3.1.1.4 泵的见证试验
注：泵买方代理人见证泵试验，能起到很多有意义的作用。见证试验有多种方式。
3.1.1.4.1
买方代理人见证 witnessing by the purchaser's representative
买方代理人出席的试验，并在原始试验数据上签字，以证实试验成功完成。
注：泵性能的最后验收有可能通过见证人进行确定。见证试验的效果很大程度上取决于见证人的专业经验和能力。见证人不仅能保证试验正确地进行，还可以在泵发往工作现场之前观测试验期间泵的运行情况。见证试验的缺点是发货时间拖延并且成本过高。在采用实时生产系统下，如果见证的进度安排导致生产拖延则会造成成本增加，因而要求见证试验的进度安排在见证这一阶段具有灵活性。
3.1.1.4.2
买方代理人远程见证 remote witnessing by the purchaser's representative
买方或其代理人在一段距离内进行的泵性能试验的见证。
注：买方可采用远程摄像系统实时远程监控整个试验。买方在试验期间可以审核和分析通过数据采集系统记录的原始数据，并对结果进行讨论和提交，以待审批。该试验类型可以节省旅差费用并加快发货速度。
3.2 与量相关的术语
3.2.1
角速度 angular velocity
每单位时间内轴旋转的弧度数。
注1：由式(1)给出：
＝2πn (1)
注2：用时间表示，例如s－1，式中n用60×min－1形式给出。
3.2.2
转速 speed of rotation
每单位时间内的转数。
3.2.3
质量流量 mass flow rate
从泵的出口法兰排出进入管路的流量。
注1：质量流量的单位用千克每秒(kg/s)表示。
注2：泵内部需用、损失或抽取的流量不计入流量：
a) 水力平衡轴向力所需的排量；
b) 冷却泵自身轴承。
注3：连接管件的泄漏、内部泄漏等不计入流量。反之，所有供其他用途的分出流量均计入流量。如：
a) 冷却电机轴承；
b) 冷却齿轮箱(轴承、油冷却器)等。
注4：这些流量是否需要计入以及如何计入分别取决于分出流量的位置和流量测量截面的位置。
3.2.4
体积流量 volume rate of flow
泵出口的体积流量，由式(2)给出：
(2)
注：本标准中，符号Q也可以表示任何给定截面处的体积流量。它是该截面处质量流量和密度的商(截面可以用脚标标示)。
3.2.5
平均速度 mean velocity
轴向流速的平均值，由式(3)给出：
(3)
注：注意在这种情况下由于沿回路的各种原因Q可能会变化。
3.2.6
局部速度 local velocity
任意给定点的流速。
3.2.7
水头 head
每单位质量流体的能量除以重力加速度g，由式(4)给出：
(4)
见3.2.16。
3.2.8
基准面 reference plane
用作高度测量基准的任一水平面。
注：为了实用，最好不要规定虚设的基准面。
3.2.9
相对基准面的高度 height above reference plane
所研究的点相对基准面的高度。
见图A.1。
注：其值：
——如果所研究的点在基准面之上，其值为正；
——如果所研究的点在基准面之下，其值为负。
3.2.10
表压 gauge pressure
相对大气压力的压力。
注1：其值：
——如果该压力高于大气压力，其值为正；
——如果该压力低于大气压力，其值为负。
注2：在本标准中，除了大气压力和液体的汽化压力以绝对压力表示外，所有的压力均指从压力计或类似的压力指示仪表上读出的表压。
3.2.11
速度水头 velocity head
每单位质量运动液体的动能除以2g，由式(5)给出。
(5)
3.2.12
总水头 total head
任一截面处的总能量。
注1：总水头由式(6)给出：
(6)
式中：
z——横截面中心相对基准面的高度；
p——所述横截面中心的表压。
注2：任一截面处的绝对总水头由式(7)给出：
(7)
3.2.13
入口总水头 inlet total head
泵入口截面处的总能量。
注：入口总水头由式(8)给出：
(8)
3.2.14
出口总水头 outlet total head
泵出口截面处的总能量。
注：出口总水头由式(9)给出：
(9)
3.2.15
扬程 pump total head
出口总水头和入口总水头的代数差。
注1：如果液体的压缩性可忽略不计，则H＝H2－H1。如果泵输送液体的压缩性明显，则密度ρ应用平均值替代：
(10)
扬程应用式(11)计算：
(11)
注2：数学上的恰当符号为H1－2。
3.2.16
比能 specific energy
每单位质量流体的能量，由式(12)给出：
y＝gH (12)
3.2.17
入口水头损失 loss of head at inlet
测量点处液体的总水头与泵入口截面处液体的总水头之差。
3.2.18
出口水头损失 loss of head at outlet
泵出口截面处液体的总水头与测量点处液体的总水头之差。
3.2.19
管路摩擦损失系数 pipe friction loss coefficient
由管路摩擦所致的水头损失的系数。
3.2.20
汽蚀余量 net positive suction head
NPSH
相对NPSH基准面的入口绝对总水头与汽化压力水头的差。
注1： NPSH由式(13)给出：
(13)
注2：此NPSH与NPSH基准面有关，而入口总水头与基准面有关。
注3：由于缩写NPSH(正体且不加粗)这种使用方式的完善性和长期性，允许其在数学公式中作为符号使用。
3.2.20.1
NPSH基准面 NPSH datum plane
〈多级泵〉通过由叶轮叶片进口边最外点所描绘的圆的中心的水平面。
3.2.20.2
NPSH基准面 NPSH datum plane
〈立轴或斜轴双吸泵〉通过较高中心的平面。
见图1。
注：制造厂家根据泵上准确的基准点负责指示出该平面的位置。
说明：
1——NPSH基准面。
图1 NPSH基准面
3.2.21
有效汽蚀余量 available NPSH
NPSHA
由装置条件确定的、规定流量下可获得的(可利用的)NPSH。
注：由于缩写NPSHA(正体且不加粗)这种使用方式的完善性和长期性，允许其在数学公式中作为符号使用。
3.2.22
必需汽蚀余量 required NPSH
NPSHR
在规定的流量、转速和输送液体的条件下，泵达到规定性能的最小汽蚀余量(出现可见汽蚀、汽蚀引起的噪声和振动的增大、扬程或效率开始下降、给定降幅的扬程或效率、汽蚀侵蚀限度)，其值由制造厂家给出。
注：由于缩写NPSHR(正体且不加粗)这种使用方式的完善性和长期性，允许其在数学公式中作为符号使用。
3.2.23
NPSH3
泵第一级扬程下降3％时的必需汽蚀余量，作为标准基准用于表示性能曲线。
注：由于缩写NPSH(正体且不加粗)这种使用方式的完善性和长期性，允许其在数学公式中作为符号使用。
3.2.24
型式数 type number
按最佳效率点计算的无因次的量。
注1：由式(14)给出：
(14)
式中：
Q′——每一吸入口的体积流量；
H′——第一级扬程；
n用s－1表示。
注2：应按第一级叶轮的最大直径取型式数。
3.2.25
泵输入功率 pump power input
P2
驱动机传输给泵的功率。
3.2.26
泵输出功率 pump power output
泵出口液体的有效功率。
注：泵输出功率由式(15)给出：
Ph＝ρQgH＝ρQy (15)
3.2.27
驱动机输入功率 driver power input
Pgr
泵驱动机吸收的功率。
3.2.28
泵最大输入功率 maximum shaft power
P2，max
由制造厂家设定的、在规定运行条件下能正常驱动泵的最大输入功率。
3.2.29
泵效率 pump efficiency
泵输出功率除以泵输入功率。
注：泵效率由式(16)给出：
(16)
3.2.30
总效率 overall efficiency
泵输出功率除以驱动机输入功率。
注：总效率由式(17)给出：
(17)
3.3 符号和脚标
表1 用作符号的基本字母表(按字母顺序排列)
符号 量 单位
A 面积 m2
D 直径 m
e 总的不确定度，相对值 ％
f 频率 s－1，Hz
g 重力加速度a m/s2
H 扬程 m
HJ 液体水头损失 m
k 当量均匀粗糙度 m
K 型式数 纯数值
l 长度 m
M 转矩 Nm
n 转速 r/min，s－1，min－1
NPSH 汽蚀余量 m
p 压力 Pa
P 功率 W
q 质量流量b kg/s
Q (体积)流量c m3/s
Re 雷诺数 纯数值
τ 容差系数，相对值 ％
t t分布 纯数值
U 平均速度 m/s
v 局部速度 m/s
V 体积 m3
y 比能 J/kg
z 相对基准面的高度 m
zD NPSH基准面(见3.2.20)与基准面位差 m
效率 ％
θ 温度 ℃
管路摩擦损失系数 纯数值
运动黏度 m2/s
ρ 密度 kg/m3
角速度 rad/s
a 原则上宜使用g的当地值。然而，对于2级和3级，g＝9.81 m/s2已足可满足使用；
g的当地值计算公式为：g＝9.7803(1＋0.0053sin2)－3×10－6Z，式中为纬度，Z为海拔。
b 质量流量符号亦可选用qm。
c 体积流量符号亦可选用qv。
表2 用作脚标的字母和数字表
脚标 意义
1 入口
1′ 入口测量截面
2 出口(除P2外)
2′ 出口测量截面
abs 绝对的
amb 周围的
D 差，基准
f 测量管流体
G 保证的
H 扬程
h 水力
gr 组合的电机/泵机组(总的)
J 损失
M 压力计的
n 转速
p 功率
Q (体积)流量
ref 基准面
sp 规定的
T 转换的，转矩
v 汽化(压力)
效率
x 在任一截面
4 泵的测量和验收准则
4.1 总则
规定的和合同中商定的规定点(工况点)，以下简称“保证点”，应通过一个验收等级和其相对应的容差进行评价。对于泵的性能试验，这个保证点通常应由保证流量QG和保证扬程HG加以确定，并且，也可选用保证效率、保证轴功率或保证必需汽蚀余量(NPSHR)加以确定。在适用的情况下，这些可选保证参数需要根据试验进行确定，试验要求分别见4.4.3和5.8。
验收等级的容差仅适用于保证点。其他规定工况点，包括其容差在内，应经制造厂家和买方另外协商。如果有其他的规定工况点但没有相对应容差的情况下，这些工况点的默认验收等级应为3级。
可通过书面合同、客户规定的泵性能曲线或类似书面的项目技术文件对保证点进行详细说明。
如果制造厂家和买方之间没有另外的商定，则下列条件适用：
a) 验收等级应与表8中所给的等级一致；
b) 试验应在清洁冷水条件下、采用本标准规定的试验方法和试验装置、且在制造厂家的试验台上进行；
c) 泵入口和出口之间的性能应予以保证；
d) 泵外端的管路和配件(弯头、变径管、阀)不在保证范围内。
实际上，测量值里的容差结合了制造容差和测量容差。表8中给出的容差系数值包括了制造容差和测量容差。
泵的性能可以随输送液体性质的不同而有显著变化。虽然不可能给出一个普通适用的规则，使之可以用输送清洁冷水时的性能预测输送其他液体时的性能，但是商定一个适合特殊工况的经验规则而泵仍用清洁冷水做试验是可行的。详见ISO/TR 17766。
如购买多台同样的泵，需要试验的泵的数量应由买方和制造厂家进行商定。
买方和制造厂家双方均有权要求见证这些试验。如果试验不在制造厂家的试验台上进行，应允许买方和制造厂家双方有机会对泵的试验装置和仪器仪表及其校准状态进行确认。
4.2 保证
制造厂家确保在保证点和规定转速下(或在某些情况下是频率和电压)，测得的泵曲线与围绕保证点的一个容差范围内相切或通过，即根据适用的验收等级确定(见表8、图2和图3)。
保证点应由保证流量QG和保证扬程HG加以确定。
此外，在规定的条件和规定的转速下，下列诸量中的一个或多个可予以保证：
a) 如4.4.3和图4、图5和图6中的规定；
1) 泵最低效率ηG，或泵的最大输入功率PG；
2) 泵和电机作为一个机组的情况下，最小机组效率ηgrG，或最大机组输入功率PgrG。
b) 保证流量下的最大必需汽蚀余量。
保证点下或泵曲线范围内的最大输入功率可以予以保证。然而，可能需要由买方和制造厂家商定大一些的容差范围。
4.3 测量不确定度
4.3.1 总则
即使使用的测量方法、所用的仪表及分析方法完全可行并符合本标准的要求，每一测量量也仍不可避免地存在不确定度。
4.3.2和4.3.3中描述的导则和方法旨在给用户提供一些资料性信息，以及一些实践方法，用户通过这些方法可对适用于本标准要求的试验以合理的置信概率进行测量不确定度的评定。
注：关于测量不确定度的综合性信息资料，见ISO/IEC Guide 99和相关文件。
4.3.2 波动
如果泵的设计或运转使得测量数值出现大幅度的波动，则可以在测量仪表中或其连接管线中设置一种能使波动幅度降低到表3给定值范围内的缓冲装置来进行测量。缓冲装置应是对称和线性的，例如毛细管，它应提供至少是包含了一个完整的波动周期内的积分值。
表3 容许波动幅度，以测量量平均值的百分数表示
测量量 容许波动幅度
1级
％ 2级
％ 3级
％
流量 ±2 ±3 ±6
压差 ±3 ±4 ±10
出口压力 ±2 ±3 ±6
入口压力 ±2 ±3 ±6
输入功率 ±2 ±3 ±6
转速 ±0.5 ±1 ±2
转矩 ±2 ±3 ±6
温度 0.3℃ 0.3℃ 0.3℃
4.3.3 总的测量不确定度的评定
4.3.3.1 随机不确定度的评定
随机不确定度，它或是由于测量系统的特征、或是由于被测量的量的变化、或是由于两者共同所致，直接以测量结果的分散形式出现。与系统不确定度不同，随机不确定度可以通过在同样条件下增加同一量的测量次数来加以降低。
每一个试验点应至少取3组读数。随机不确定度eR计算如下：
测量不确定度随机部分的评定通过观测值的平均值和标准偏差计算得出。对于读数的不确定度，用流量Q，扬程H和功率P的实际测量读数代替x。
如果n表示读数的次数，那么一组重复测量观测值xi(i＝1…n)的算术平均值 为：
(18)
这组观测值的标准偏差s从式(19)导出：
(19)
随机效应产生的平均值的相对不确定度值eR从式(20)导出：
(20)
式中：
t——表4中n的一个函数。
注1：如果总的不确定度值e不能满足表7中的准则要求，那么测量的随机不确定度值eR可以通过在同样条件下增加同一量的测量次数来加以降低。
注2：本标准中规定的随机部分属于A类不确定度(见ISO/IEC Guide 99)。
表4 t分布数值(基于95％置信度)
4.3.3.2 系统不确定度的评定
当通过零点调整、校准、仔细地测量尺寸和正确地安装等将已知的所有误差均消除之后，仍然会留有不确定度，它永远不会消失。即使仍使用同一仪表和同样测量方法，也不能通过重复测量使其降低。
系统不确定度eS的评定实际上是以测量标准的校准为基础。表5给出了系统不确定度的容许相对值。
表5 系统不确定度eS的容许相对值
测量量 最大容许系统不确定度(保证点)
1级
％ 2级和3级
％
流量 ±1.5 ±2.5
压差 ±1.0 ±2.5
出口压力 ±1.0 ±2.5
入口压力 ±1.0 ±2.5
NPSH试验的入口压力 ±0.5a ±1.0
驱动机输入功率 ±1.0 ±2.0
转速 ±0.35 ±1.4
转矩 ±0.9 ±2.0
a 解释参见附录J。
4.3.3.3 总体的不确定度
总体的不确定度值e从式(21)导出：
(21)
表6给出了总体的不确定度e的容许值。
注：本标准规定的总体不确定度等同于扩展测量不确定度(见ISO/IEC Guide 99)。
表6 总测量不确定度的容许值
量 符号 1级
％ 2级、3级
％
流量 eQ ±2.0 ±3.5
转速 en ±0.5 ±2.0
转矩 eT ±1.4 ±3.0
扬程 eH ±1.5 ±3.5
驱动机输入功率 ePgr ±1.5 ±3.5
泵输入功率(由转矩和转速计算得出) ep ±1.5 ±3.5
泵输入功率(由驱动机输入功率和电机效率计算得出) eP ±2.0 ±4.0
4.3.3.4 效率总体测量不确定度的评定
总效率和泵效率的总体测量不确定度按式(22)～式(24)计算：
(22)
如果效率由转矩和转速计算得出：
(23)
如果效率由泵输入功率计算得出：
(24)
利用表6中给出的值进行计算即得出表7所给的结果。
表7 效率总体不确定度最大导出值
量 符号 1级
％ 2级和3级
％
总效率(由Q，H和Pgr计算得出) eηgr ±2.9 ±6.1
泵效率(由Q，H，M和n计算得出) eη ±2.9 ±6.1
泵效率(由Q，H，Pgr和ηmot计算得出) eη ±3.2 ±6.4
4.4 性能试验验收等级和容差系数值
4.4.1 总则
本标准中规定了6种泵性能试验验收等级，即1B、1E、1U、2B、2U和3B。1级要求最严格，其中1U级和2U级是单向容差，1B级、2B级和3B级是双向容差。1E级在本质上也是双向容差，并且在能效相关领域很重要。
注：对于流量和扬程，1U级、1E级和1B级具有相同的容差系数。
买方和制造厂家可在应用等级上进行协商，以判定一特定的泵是否满足保证点的要求。如果给定一个保证点，但是没有规定验收等级，可以采用4.5中所述的默认试验验收等级。
表8中给出了泵扬程、流量、功率和效率的保证点验收等级。所有的容差系数均以保证值的百分数表示。
表8 泵试验验收等级和相应的容差系数值
等级 1 3 保证要求
△τQ 10％ 16％ 18％
△τH 6％ 10％ 14％
验收等级 1U 1E 1B 2B 2U 3B
τQ ＋10％ ±5％ ±8％ ＋16％ ±9％ 强制
τH ＋6％ ±3％ ±5％ ＋10％ ±7％
τP ＋10％ ＋4％ ＋8％ ＋16％ ＋9％ 可选
τη ≥0％ －3％ －5％ －7％
注：τx(x＝Q，H，P，η)代表指示数量的容差系数。
4.4.2 泵输入功率不大于10 kW的泵的容差系数值
对于泵输入功率不大于10 kW的泵，表8中给出的容差系数过于严格。如制造厂家和买方无另外商定，应使用下列容差系数：
——流量τQ＝±10％；
——扬程τH＝±8％。
效率的容差系数τη，在保证的情况下可用式(25)计算：
(25)
式中泵输入功率P2为工作范围内最大输入功率，以kW表示。容差系数τPgr可用式(26)计算：
(26)
4.4.3 流量和扬程的评定
保证点的评定应在规定转速下完成。当试验转速等同于规定转速或电动机-泵合为一体的泵机组(例如潜没式泵、共轴泵以及与电机连接且同步试验的所有泵)的试验时，不需要进行转速换算。对于试验转速不同于规定转速的试验，每一试验点应采用相似定律换算成规定转速进行计算。
流量和扬程的容差适用于以下方式：
——泵流量容差适用于保证扬程HG下的保证流量QG；
——泵扬程容差适用于保证流量QG下的保证扬程HG。
如果流量或者扬程，或者两者同时均在适用的容差(见图2和图3)范围内，则满足验收要求。
