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CJ 128-2007 English PDF (CJ128-2007)

CJ 128-2007 English PDF (CJ128-2007)

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CJ 128-2007: Heat meters

This Standard specifies terms and definitions, technical characteristic, requirement, test method, test rules, marking, packing, and storage of heat meters.
CJ 128-2007
GB
INDUSTRY STANDARD OF THE
PEOPLE REPUBLIC OF CHINA
ICS 91.140.60
P 40
Replacing CJ 128-2000
Heat Meters
ISSUED ON. OCTOBER 15, 2007
IMPLEMENTED ON. APRIL 1, 2008
Issued by. Ministry of Construction of the People's Republic of China
Table of Contents
1 Scope ... 5
2 Normative References ... 5
3 Terms and Definitions ... 6
4 Technical characteristics ... 9
5 Requirements ... 12
6 Test Method ... 17
7 Inspection rules ... 22
8 Marking, Packing and Storage ... 24
Annex A (Informative) Water density and enthalpy value ... 26
Annex B (Normative) Photoelectric interface ... 29
Annex C (Normative) Structure and Installation of Platinum Resistance Temperature Sensor ... 33
Annex D (Normative) Test and calculation for metering accuracy of heat meter ... 47 Annex E (Normative) Test and calculation for calculator accuracy ... 48 Annex F (Normative) Test and calculation of temperature sensor accuracy ... 50 Annex G (Normative) Test and calculation of flow sensor accuracy ... 53 Foreword
The articles 4.2.2 4.2.4 4.2.5 4.3.2 4.3.3 and 5.1~5.12 in this Standard are compulsory ones; the rest are recommendatory.
This Standard replaces CJ-128-2000 "Heat Meters", from the implementation date. This Standard is the revision to CJ 128-2000 "Heat Meters". This revision references to EU standard EN 1434-2007 "Heat meters". The major technical contents are consistent with EN 1434; and it is consistent with JJG 225 "Verification Regulation of heat Meters".
Compared with CJ 128-2000, the following aspects have been made to this Standard. ?€? Extend the flow-rate application scope of heat meter; add the requirements of the heat meter with low flow-rate and large caliber;
?€? Add the requirements in installation length of heat meters;
?€? Add the requirements in pipe network water quality;
?€? Add the related requirements in cooling meter;
?€? Add Class C environmental requirement of heat meter;
?€? Add the requirements in data storage;
?€? Add the requirements in repetitiveness;
?€? Raise the requirements in electromagnetic compatibility;
?€? Raise the requirement in water temperature of exit-factory test; specify the different water temperature conditions according to the type of heat meter in type approval test;
?€? Delete the change size structural styles not used in China; make significant amendment on installation drawing in the requirements in structure and
installation of platinum resistance temperature sensor;
?€? Add the technical requirements in photoelectric interface of heat meter; ?€? Add the requirements in the communication protocol used in heat meter data transfer;
?€? Delete the technical contents in prepayment devices in Annex G in the former standard.
Annex B, Annex C, Annex D, Annex E, Annex F and Annex G in this Standard are normative; Annex A is informative.
Heat Meters
1 Scope
This Standard specifies terms and definitions, technical characteristic, requirement, test method, test rules, marking, packing, and storage of heat meters.
This Standard is applicable to heat meters of which the flowing medium is water, the temperature is 2??C~150??C, and the pressure is not larger than 2.5 MPa.
2 Normative References
The following normative documents contain provisions which, through reference in this text, constitute that provisions of this Standard. For dated reference, the subsequent amendments or revisions of these publications do not apply. Parties who reach an agreement based on this Standard are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below. For undated references, the latest edition of the normative document referred to applies. GB 191 Packaging - Pictorial marking for handling of goods
GB/T 2423.1 Environmental testing - Part 2. Test methods - Tests A. Cold GB/T 2423.2 Environmental testing - Part 2. Test methods - Tests A. Dry heat GB/T 2423.3 Environmental testing - Part 2. Test methods - Tests A. Damp heat Steady
GB/T 2423.4 Environmental testing for electric and electronic products - Part 2. Test method - Test Db. Damp heat, cyclic (12h+12h cycle)
GB 4208-1993 Degrees of protection provided by enclosure (IP code)
GB 4706.1 Household and similar electrical appliances - Safety - Part 1. General requirements
GB/T 9113.1 Integral steel pipe flanges with flat face or raised face
GB/T 17626.2 Electromagnetic compatibility (EMC) - 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 17626.11 Electromagnetic compatibility - Testing and measurement
techniques - Voltage dips, short interruptions and voltage variations immunity tests CJJ 34 Design code of district heating network
CJ/T 188-2004 Technical requirements of utility meters data transmission 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 Standard.
3.1
Heat meter
Meter that meters and displays the heat energy that the water-flow releases or absorbs when passing heat exchange system.
3.2
Complete heat meter
Non-decomposable heat meter consisted of flow sensor, calculator and temperature sensor pair.
3.3
Combined heat meter
Heat meter consisted of flow sensor, calculator and temperature sensor pair. 3.4
Cooling meter
Heat meter that meters the cooling amount in which the fluid medium temperature is 2??C~ 30??C and the temperature difference is not higher than 20K.
3.12
Maximum temperature difference
Upper limit value of a temperature difference, under which the accuracy of a heat meter shall not exceed the error limit.
3.13
Flow-rate
Volume or mass of the heat carrier water that flows across a heat meter in unit time. 3.14
Minimum flow-rate
Lower limit of the flow-rate of water-flow that flows across a heat meter, under which the accuracy of a heat meter shall not exceed the error limit.
3.15
The permanent flow-rate
Water flow-rate of a system under long-term normal continuous operation, under which the accuracy of a heat meter shall not exceed the error limit.
3.16
Maximum flow-rate
Water extreme flow-rate of the water-flow that flows across a heat meter under normal operation condition in a short time (1 h/d; < 200 h/a), under which the accuracy of a heat meter shall not exceed the error limit.
3.17
Total volume
Total volume of water flowing across a heat meter.
3.18
The highest temperature
Maximum allowable temperature of water, when the accuracy of a heat meter does not exceed the error limit.
3.19
The lowest temperature
Minimum allowable temperature of water, when the accuracy of a heat meter does not exceed the error limit.
3.20
Maximum admissible working pressure
Maximum working pressure that a heat meter can bear with when it continuously works under the highest temperature.
3.21
Pressure loss
Loss of pressure caused by a heat meter at specified flow-rate.
3.22
Admissible pressure loss
Limit of pressure loss of the water-flow that flows across a heat meter at permanent flow-rate.
3.23
Maximum thermal power
Possible maximum value of thermal power when the accuracy of a heat meter does not exceed the error limit.
4 Technical characteristics
4.1 heat metering
When the water-flow flows across complete heat meter or combined heat meter installed in a heat exchange system, the heat energy quantity released and absorbed by the system is calculated and displayed by the calculator according to the flow-rate given by flow sensor, the temperature of water feed and back acquired by temperature sensor pair, and the water flowing time. The basic formula is. (1)
Where,
Q ?€? heat released and absorbed by the system, J;
is .
5.8 Repetitiveness
The repeatability error of a heat meter shall not be greater than the maximal permissible error limit.
5.9 Endurance
The effective use cycle of a heat meter shall be larger than 5 years, and it shall be examined by endurance test.
5.10 Safety requirements
5.10.1 Power-off prot...

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