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GB/T 32224-2015 English PDF (GBT32224-2015)

GB/T 32224-2015 English PDF (GBT32224-2015)

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GB/T 32224-2015: Heat meters

This standard specifies the terms and definitions, technical characteristics, requirements, test methods, inspection rules, marking, packaging, transportation, storage of heat meters. This standard applies to the production and inspection of heat meters which use water as medium.
GB/T 32224-2015
NATIONAL STANDARD OF THE
PEOPLE REPUBLIC OF CHINA
ICS 91.140.60
P 40
Heat meters
ISSUED ON: DECEMBER 10, 2015
IMPLEMENTED ON: NOVEMBER 01, 2016
Issued by: General Administration of Quality Supervision, Inspection and Quarantine of PRC;
Standardization Administration of PRC.
Table of Contents
Foreword ... 3
1 Scope ... 4
2 Normative references ... 4
3 Terms and definitions ... 5
4 Technical characteristics ... 9
5 Requirements ... 13
6 Test methods ... 19
7 Inspection rules ... 27
8 Marking, packaging, transportation, storage ... 29
Appendix A (Normative) Density and enthalpy of water ... 31
Appendix B (Normative) Structure and installation of platinum-resistance temperature sensor ... 35
Appendix C (Normative) Optical interface and data communication ... 51 Appendix D (Normative) Test and calculation of measurement accuracy of heat meter ... 53
Appendix E (Normative) Test and calculation of calculator?€?s accuracy ... 54 Appendix F (Normative) Test and calculation of accuracy of temperature sensor ... 56
Appendix G (Normative) Test and calculation of accuracy of flow sensor ... 60 Heat meters
1 Scope
This standard specifies the terms and definitions, technical characteristics, requirements, test methods, inspection rules, marking, packaging,
transportation, storage of heat meters.
This standard applies to the production and inspection of heat meters which use water as medium.
2 Normative references
The following documents are essential to the application of this document. For the dated documents, only the versions with the dates indicated are applicable to this document; for the undated documents, only the latest version (including all the amendments) are applicable to this standard.
GB/T 191 Packaging - Pictorial marking for handling of goods
GB/T 2423.1 Environmental testing for electric and electronic and electronic products - Part 2: Test methods - Tests A: Cold
GB/T 2423.2 Environmental testing for electric and electronic products - Part 2: Test methods - Tests B: Dry heat
GB/T 2423.4 Environmental testing for electric and electronic products - Part 2: Test method - Test Db: Damp heat, cyclic (12h + 12h cycle)
GB/T 26831.1 Society energy metering for reading system specification - Part 1: Data exchange
GB/T 26831.2 Society energy metering for reading system specification - Part 2: Physical and link layer
GB/T 26831.3 Society energy metering for reading system specification - Part 3: Dedicated application layer
GB 4208-2008 Degrees of protection provided by enclosure (IP code)
GB 4706.1-2005 Household and similar electrical appliances - Safety - Part 1: General requirements
GB/T 9113 Integral steel pipe flange
GB/T 17241.6 Integral cast iron flanges
GB/T 17626.2 Electromagnetic compatibility - Testing and measurement
techniques - Electrostatic discharge immunity test
GB/T 17626.3 Electromagnetic compatibility - Testing and measurement
techniques - Radiated, radio-frequency, electromagnetic field immunity test GB/T 17626.4 Electromagnetic compatibility - Testing and measurement
techniques - Electrical fast transient/burst immunity test
GB/T 17626.5 Electromagnetic compatibility - Testing and measurement
techniques - Surge immunity test
GB/T 17626.8 Electromagnetic compatibility (EMC) - Part 4-8: Testing and measurement techniques - Power frequency magnetic field immunity test
GB/T 17626.9 Electromagnetic compatibility - Testing and measurement
techniques - Pulse magnetic field immunity test
GB/T 17626.11 Electromagnetic compatibility - Testing and measurement
techniques - Voltage dips, short interruptions and voltage variations
immunity tests
GB/T 17626.29 Electromagnetic compatibility (EMC) - Testing and
measurement techniques - Voltage dips short interruptions and voltage
variations on D.C. input power port immunity tests
CJJ 34 Design code for city heating network
JB/T 8622-1997 Technical specification and reference table for industrial platinum thermal resistance
JB/T 9329 Basic environmental conditions and testing methods for
instruments transportation and storage in the transportation
3 Terms and definitions
The following terms and definitions apply to this document.
3.1
Heat meter
A meter which is used to measure and display the released or absorbed
temperature of water supply and water return of the heat exchange system. 3.9
Calculator
A component that receives signals from the flow sensor and the temperature sensor pair for heat calculation, storage, display of heat values as
exchanged by the system.
3.10
Temperature difference
The difference between the temperature of water supply and water return of the heat exchange system.
3.11
Minimum temperature difference
The lower limit of the temperature difference, under which the accuracy of the heat meter shall not exceed the error limit.
3.12
Maximum temperature difference
The upper limit of the temperature difference, under which the accuracy of the heat meter shall not exceed the error limit.
3.13
Minimum flowrate
Under the condition that the accuracy of the heat meter does not exceed the error limit, the lower limit of flowrate of the water when it flows through the heat meter.
3.14
The permanent flowrate
Under the condition that the accuracy of the heat meter does not exceed the error limit, the upper limit of flowrate when the heat meter is continuously operated for a long time.
3.15
4 Technical characteristics
4.1 Heat measurement
4.1.1 Method of heat measurement
The heat may be measured by the enthalpy difference method or the thermal coefficient method.
4.1.2 Enthalpy difference method
When water flows through an complete heat meter or a combined heat meter which is installed in a heat exchange system, according to the flowrate as given by the flow sensor and the temperature signal of water supply and return as given by the temperature sensor pair as well as the time the water flows, the calculator is used to calculate and display the released or absorbed heat of this system. The released or absorbed heat of this system is calculated according to formula (1):
Where:
Q - The heat released or absorbed by the system, in Joule (J);
qm - The mass flowrate of water which flows through the heat meter, in
kilograms per hour (kg/h);
qv - The volume flowrate of water which flows through the heat meter, in cubic meters per hour (m3/h);
?? - The density of water which flows through the heat meter, in kilograms per cubic meter (kg/m3);
??h - The difference in enthalpy of water at the temperature of water supply and water return in the heat exchange system, in Joule per kilogram (J/kg); ?? - Time, in hours (h).
4.1.3 Thermal coefficient method
When water flows through an complete heat meter or a combined heat meter which is installed in a heat exchange system, according to the signal of temperature difference of water supply and water return as given by the temperature sensor pair as well as the total volume (the volume) of water as given by the flow sensor, the calculator is used to calculate and display the 5.2.1.3 The visible height of the displayed number shall not be less than 4 mm. The fractional part of the displayed value shall be clearly distinguishable from the rest of the value. When using display by multiple pages, the value as displayed on each page shall be complete.
5.2.2 Resolution of display
5.2.2.1 In the using mode, the minimum display resolution shall comply with the following requirements:
a) Calorific value: 1 kW ?€? h, 1 MW ?€? h or 1 MJ, 1 GJ;
b) Temperature value: 0.1 ??C;
c) Temperature difference: 0.1 K;
d) Total volume:
1) Nominal diameter DN15 ~ DN25: 0.01 m3;
2) Nominal diameter DN32 ~ DN400: 0.1 m3.
5.2.2.2 In the verification mode, the minimum display resolution shall comply with the following requirements:
a) Calorific value: 0.001 kW ?€? h or 0.001 MJ;
b) Temperature value: 0.01 ??C;
c) Temperature difference: 0.01 K;
d) Total volume:
1) Nominal diameter DN15 ~ DN25: 0.00001 m3;
2) Nominal diameter DN32 ~ DN100: 0.0001 m3;
3) Nominal diameter DN125 ~ DN400: 0.001m3.
5.2.2.3 The displayed value and unit of display shall be clearly and definitely marked. The displayed value shall be a valid number.
5.2.3 Display value of heat
5.2.3.1 When the heat meter is continuously operated for 3000 h under the maximum thermal power, the heat shall not exceed the maximum display value. 5.2.3.2 When the heat meter is continuously operated for 1 h under the
maximum thermal power, the minimum effective display number shall be added The accuracy of the flow sensor of the grade-1 meter shall not exceed ??3.5%. The accuracy of the flow sensor of the grade-2 and grade-3 shall not exceed ?? 5%.
5.6 Admissible pressure loss
When the heat meter is operated under the permanent flowrate, the admissible pressure loss is not more than 0.025 MPa.
5.7 Power supply
5.7.1 Basic requirements
The heat meter may use either a built-in battery or an external power supply. For heat meters which have a nominal diameter of less than or equal to DN40, it shall use the built-in battery.
5.7.2 Service life of built-in battery
The service life of the built-in battery shall be more than (5 + 1) years. 5.7.3 External power supply
5.7.3.1 The externally connected AC power supply?€?s voltage shall be
. The frequency fn = (50 ?? 1) Hz.
5.7.3.2 The externally connected DC power supply?€?s voltage may be (5 ?? 0.25) V, (12 ?? 0.6) V or (24 ?? 1.2) V.
5.8 Repeatability
The error of repeatability of the heat meter shall not exceed the maximum admissible error limit.
5.9 Durability
The effective life cycle of the heat meter shall be more than 5 years. The effective life cycle shall be assessed by the durability test.
5.10 Safety performance
5.10.1 Power failure protection
When the power supply stops supplying power, the heat meter shall be able to save the heat stored before the power failure, the total volume and the corresponding time data, the historical data in 5.3. After the power supply is restored, it shall automatically resume normal operation.
5.10.2 Undervoltage prompt of battery?€?s voltage
When the voltage of the battery drops to the set undervoltage value, the heat meter shall have an undervoltage prompt message and shall be in normal
working state.
5.10.3 Resistance to magnetic-field interference
When subjected to a magnetic-field interference which has a strength of not more than 100 kA/m, the heat meter shall work normally and the data is normal. 5.10.4 Electrical insulation
When the heat meter uses AC power supply, the electrical insulation shall comply with the provisions of category-I appliances in GB 4706.1-2005.
5.10.5 degree of protection of shell
The classification of the degree of protection of the shell shall be according to the provisions of GB 4208-2008.
For the heat meter which has an environment of use of category-A and
category-B, the degree of protection of shell shall be IP54. For the heat meter which has an environment of use of category-C, the degree of protection of shell shall be IP65. For the heat meter which has an environment of use of category-D, the degree of protection of shell shall be IP65/IP68. The degree of protection of the shell of the cooling meter and the meters for heating and cooling shall be IP65. The shell of the heat meter shall have a marking of degree of protection.
5.10.6 Seal
The heat meter shall have a reliable seal. Without damaging the seal, it shall not dismantle the heat meter and relevant components.
5.11 Optical interface
The heat meter shall have an optical interface. Its structural and optical characteristics shall comply with the provisions of Appendix C.
5.12 Data communication
The data communication of the heat meter may be equipped with interfaces such as M-bus, RS-485, wireless transmission. The communication protocol shall comply with the provisions of Appendix C.
6.2.2 Resolution of display
6.2.2.1 Visually check the heat meter. In the using mode, the resolution of display shall comply with the provisions of 5.2.2.1.
6.2.2.2 Output the parameters of the heat meter from the optical interface of the heat meter. In the verification mode, the resolution of display shall comply with the provisions of 5.2.2.2.
6.2.3 Displayed value of heat
Make the heat meter continuously operate at the maximum thermal power for 1 h. Respectively record the displayed value of heat at the beginning and end of the test. Use visual inspection and calculation. The displayed value of heat shall comply with the requirements of 5.2.3.
6.3 Data storage
Simulate the operation of the heat meter for 18 months. Check the content and period of the data storage, which shall meet the requirements of 5.3.
6.4 Strength and tightness
6.4.1 Strength
For the heat meter which is installed in the closed pipeline, load the medium of water which has a temperature of the upper temperature limit minus 5 ??C ~ 15 ??C and a pressure of 1.5 times the maximum working pressure. After 30 minutes of stabilization, check the heat meter, which shall comply with the requirements of 5.4.
6.4.2 Tightness
For the heat meter, load the medium of water which has a temperature of the upper temperature limit minus 5 ??C ~ 15 ??C and a pressure of 1.5 times the maximum working pressure. After 30 minutes of stabilization, check the heat meter, which shall comply with the requirements of 5.4.
6.5 Accuracy
6.5.1 Measurement accuracy of heat meter
The test and calculation of the measurement accuracy of the heat meter shall be carried out according to the provisions of Appendix D.
6.5.2 Accuracy of calculator
The test and calculation of the accuracy of the calculator shall be carried out a) Install the heat meter on the test bench to run it normally under the following conditions:
1) Flowrate: the permanent flowrate;
2) Water temperature: The heat meter is (50 ?? 5) ??C. The cooling meter is (15 ?? 5) ??C.
b) During the test, first empty the air from the heat meter, differential pressure gauge, pipeline. When the pressure is stable, measure the pressure
difference between the front and back pressure measuring points.
c) The test shall separately measure the pressure difference between the front and back pressure measuring points when installing the heat meter and not installing the heat meter (replaced by a straight pipe segment of the same diameter). The difference between the two measured values is
the admissible pressure loss of the heat meter.
d) Admissible pressure loss shall comply with the provisions of 5.6.
6.7 Power supply
The test of service life of the built-in battery is performed as follows: a) Install the heat meter on the test bench, to run it normally under the following conditions.
b) Flowrate: the permanent flowrate;
c) Water temperature: The heat meter is (50 ?? 5) ??C. The cooling meter is (15 ?? 5) ??C.
d) Measure the working curve of power supply?€?s current of the heat meter for no less than 10 complete working cycles. Use 80% of the rated capacity
value of the battery as the reference data, calculate the effective value of the power supply?€?s current of the heat meter and the corresponding
battery life, which shall comply with the provisions of 5.7.2.
6.8 Repeatability
According to the test requirements for the measurement accuracy of the heat meter, at the same test conditions and the same test point, test the accuracy of the heat meter for 3 times. The maximum difference between any 2 test values shall meet the requirements of 5.8.
6.9 Durability
6.9.1 Durability of flow sensor
b) The flowrate shall be the maximum flowrate qs of the heat meter. The deviation is ;
c) The flow sensor runs continuously for 300 h.
6.9.1.4 After the durability test A and the durability test B are completed, the heat meter shall be at (50 ?? 5) ??C and the cooling meter shall be at the water temperature of (15 ?? 5) ??C; check the accuracy of the flow sensor of the heat meter, which shall meet the requirements of 5.5.4.
6.9.2 Durability of temperature sensor
The durability test of the temperature sensor shall comply with the following requirements:
a) Place the temperature sensor pair in the constant-temperature bath.
Slowly increase the temperature to the upper limit of the product's
calibrated use temperature. Then place it in room-temperature air. Slowly reduce the temperature to the lower limit of the product's calibrated use temperature. Repeat the temperature rise-fall for 10 times.
b) During the test, the temperature sensor shall have an immersion depth of 90% ~ 99% of its total length at each temperature boundary. Meanwhile
the temperature shall be corrected.
c) After the test is completed, check whether the accuracy of the temperature sensor pair complies with the provisions of 5.5.3. The insulation
performance shall comply with the provisions of 4.2.3.3.
6.10 Safety performance
6.10.1 Power failure protection
Make the calculator run for 24 h under the maximum temperature difference and the permanent flowrate condition. Then stop running for 24 h. Record the stored data of the heat meter. Interrupt the heat meter?€?s power supply for more than 24 h. Restore the normal power supply to the heat meter. Check the stored data before and after the interruption of power supply, which shall comply with the provisions of 5.10.1.
6.10.2 Undervoltage prompt of battery
The test of undervoltage prompt of battery shall meet the following
requirements:
a) The test instrument is:
- Environment category;
- Marking of degree of protection;
- Marking and number of meter manufacture license.
8.2 Packaging
On the outside of the packaging box, according to the requirements of GB/T 191, print the marks of upwards, avoid moisture, handle with care; indicate the manufacturer?€?s name, address, marking and number of meter manufacture
license, net weight, data of production.
The accompanied files in the box shall include:
- Product?€?s certificate;
- Instruction manual;
- Packing list.
8.3 Transportation
The heat meter shall be placed according to the marks during transportation. It shall not be directly affected by rain, frost or fog. It shall not be damaged by extrusion or impact.
8.4 Storage
8.4.1 The height of the product mat from the ground shall not be less than 0.3 m, the distance from the four walls shall not be less than 1 m, the distance from the heating equipment shall not be less than 2 m.
8.4.2 The environmental conditions of the warehouse shall comply with the following provisions:
a) Temperature:
- Environment category-A and environment category-C: 5 ??C ~ 55 ??C;
- Environment category-B and environment category-D: -25 ??C ~ 55 ??C.
b) Relative humidity: < 80%.
c) There shall be no acid, alkali, flammable, explosive, toxic, corrosive items in the warehouse. It shall avoid the actions of strong electromagnetic fields and direct sunlight.
Appendix C
(Normative)
Optical interface and data communication
C.1 Optical interface
The optical interface shall comply with the provisi...

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