Chinese People's Republic of China Urban Construction Industry Standard
CJ 128-2000
Heat meters
Issued 2001-02-05 Implemented 2001-06-01
Chinese People's Republic of China
Ministry of Construction of the People's Republic of China
Title
Preface ( 2 )
1 Scope ( 3 )
2 Ministry of Construction of the People's Republic of China
Introduction
1 Scope ( 2 )
2 References to Standards ( 3 )
3 Terminology ( 3 )
4 Technical Characteristics ( 4 )
5 Technical Requirements ( 6 )
6 Test Methods ( 9 )
7 Inspection Rules (11 )
8 Marking, packaging and storage ( 12 )
Appendix A (appendix to the standard) water density and enthalpy table ( 14 )
Appendix B (appendix to the standard) platinum resistance temperature sensor mounting requirements ( 17 )
Appendix C (appendix to the standard) flow sensor accuracy test ( 19 )
Appendix D (standard) temperature sensor accuracy test ( 19 )
Appendix D (standard) temperature sensor accuracy test ( 19 )
Appendix D (appendix) temperature sensor accuracy test ( 19 )
Appendix D (appendix to the standard) temperature sensor accuracy test ( 19 ) 2000
Preface
"Heat meter" standard in China for the first time. Standard development process combined with China's heat meter development, production, use of the situation, with reference to the European heat meter standard EN1434 (Heat meters) and the International Organization of Legal Metrology R75 international recommendations (OIML-R75). This standard adopts the EN1434 in the EN1434.1, EN1434.2, EN1434.4, EN1434.5 four standards in the main content. The two standards EN1434.3 and EN1434.6 are not used for the time being. The structure and application of platinum resistance basically adopts the European standard EN1434.2. In view of the R75 international recommendations are also modified in accordance with EN1434, therefore, the accuracy level of this standard is formulated with reference to EN1434.
Standard although the content of the EN1434.3 is not prepared for the time being, but in order to heat meter in the test process there is an output signal interface, but also for signal transmission or other purposes, the provisions of the heat meter should be a standard communication interface.
This standard has seven appendices. Appendix A to Appendix F are standard appendices. Appendix A, Appendix C to Appendix F on the density and enthalpy of water, as well as flow sensors, temperature sensors, calculators and calorimeters accuracy measurements and calculations, the provisions of the European standard than the details of the easy to use. Appendix G is only for the heat meter signal transmission and prepayment technology to provide the conditions for the development of the appendix is prompted.
This standard chapter 4 4.2.3, 4.2.4, 4.2.5, 4.3.3, 4.3.4, chapter 5, section 5.2 to 5.7, chapter 6, section 6.2, are mandatory provisions, and the rest of the recommended provisions.
This standard is proposed by the institute of standardization and pricing of the ministry of construction.
This standard by the ministry of construction urban construction standard technical focal point unit of the ministry of construction urban construction research institute focal point.
This standard drafting unit: the Ministry of Construction Urban Construction Research Institute, Institute of Physics of the Chinese Academy of Sciences, Beijing Debaopanhua electromechanical limited company, Tsinghua University, Dandong Skye electronic development limited liability company, Tianjin Sain Electronic Technology Co. Ltd, Dalian Tianzheng Thermal Automation Equipment Co., Ltd, Siemens Building Technologies (Hong Kong) Ltd, Danfoss Inc.
The main drafter of this standard: Li Guoxiang Lv Shijian Wang Shuduo Wang Zuochun Di Hongfa Shi Jianjun Zuo Ye Wang Jianguo Shen Xiuli Xu Yanqing Zheng Jifa Shao Kangwen Li Bintao
This standard entrusted to the Ministry of Construction, Urban Construction Research Institute is responsible for interpretation.
Chinese people*** and the State urban construction industry standards
Heat meters CJ 128-2000
Heat meters
1 Scope
This standard specifies the terminology of the heat meter, technical characteristics, technical requirements, test methods, test rules, signs, packaging and storage conditions. Storage conditions.
This standard applies to the flow medium for water, temperature 4 ℃ ~ 150 ℃, the pressure is not greater than 2.5MPa heat meter.
2 References to standards
The following standards contain provisions that constitute the provisions of this standard by reference in this standard. All standards are valid at the time of publication of this standard. All standards will be revised, the use of this standard parties should explore the possibility of using the latest version of the following standards.
GB191-1990 packaging, storage and transportation of graphic symbols
GB/T778.3-1996 cold water meter Part 3: test methods and test equipment
GB2423.1-1989 electrical and electronic products, basic environmental test procedures Test A: low-temperature test method
GB2423.2-1989 electrical and electronic products, basic environmental test procedures Test A: low-temperature test method
GB2423.2-1989 electrician GB2423.2-1989 Basic Environmental Test Specification for Electrical and Electronic Products Test B: High Temperature Test Method
GB2423.3-1993 Basic Environmental Test Specification for Electrical and Electronic Products Test Ca: Constant Damp Heat Test Method
GB2423.4-1993 Basic Environmental Test Specification for Electrical and Electronic Products Test Cb: Cyclic Damp Heat Test Method
GB2828- 1987 Sampling for Lot-by-Lot Inspection and Counting
GB2423.1-1989 Test A: Low Temperature Test Method 1987 Batch-by-batch inspection and counting sampling procedures and sampling table
GB/T2829-1997 Cycle inspection and counting sampling procedures and sampling table
GB4208-1993 enclosure protection level (IP code)
GB4706.1-1992 household and similar use of electrical appliances and the safety requirements of the
GB7306- 1987 Pipe Threads Sealed with Threads
GB7307-1987 Pipe Threads Sealed with Non-Threads
GB9113-1988 Dimensions of Steel Pipe Flanges
GB/T17626.2-1998 Electromagnetic Compatibility Test and Measurement Techniques Electrostatic Discharge Immunity Test
GB/T17626.3-1998 Electromagnetic Compatibility Test and Measurement Techniques Electrostatic discharge immunity test
GB/T17626.3-1998 Electromagnetic Compatibility Test and Measurement Techniques Electromagnetic Compatibility Test and Measurement Techniques Electromagnetic compatibility test and measurement techniques 1998 electromagnetic compatibility test and measurement techniques radio frequency electromagnetic field radiation immunity test
JB/T8622-1997 industrial platinum RTD technical conditions and scale
JB/T8802-1998 specification for hot water meter
JB/T9329-1999 instrumentation, transportation, storage, and test methods for basic environmental conditions and test methods
3 Terminology
3.1 Heat meterHeat meter
The meter used to measure and display the water flow through the heat exchange system to release or absorb heat.
3.2 Complete heat meter
Incomplete heat meter
Incomplete heat meter consisting of a flow sensor, a calculator, and a paired temperature sensor that cannot be disassembled.
3.3 Combined heat meterCombined heat meter
Combined heat meter by the flow sensor, calculator, paired temperature sensors and other components.
3.4 Flow sensor Flow sensor
Installed in the heat exchange system, used to collect water flow and send out the flow signal components.
3.5 Temperature sensor Temperature sensor
Installed in the heat exchange system, used to collect the temperature of the water and send out temperature signals.
CJ 128-2000
3.6 Temperature sensor pair
In the same heat meter, respectively, used to measure the inlet and outlet temperatures of the heat exchange system, a pair of measurement characteristics of the same or similar temperature sensor.
3.7 Calculator Calculator
Receives signals from the flow sensor and the paired temperature sensor, performs heat calculations, and stores and displays the value of heat exchanged by the system.
3.8 Temperature difference (Δt) Temperature difference
The difference in temperature between the inlet and outlet water of a heat exchange system.
3.9 Minimum temperature difference (Δtmin) Minimum temperature difference
Temperature difference of the lower limit value, in this temperature difference, the accuracy of the heat meter should not exceed the error limit.
3.10 Maximum temperature difference (Δtmax), Maximum temperature difference
Temperature difference of the upper limit, in this temperature difference, the accuracy of the heat meter should not exceed the error limit.
3.11 Flow-rate (q) Flow-rate
Unit time, flow through the heat meter of the volume or mass of the heat carrier water. qv is the volume flow rate, qm is the mass flow rate.
3.12 Minimum flow-rate (qmin) Minimum flow-rate
The minimum flow rate of water flow through the heat exchange system, at this flow rate, the accuracy of the heat meter should not exceed the error limit.
3.13 common flow rate (qp) The permanent flow-rate
Normal continuous operation of the system, the maximum flow of water, at this flow rate, the accuracy of the heat meter should not exceed the error limit.
3.14 Maximum flow (qmax) Maximum flow-rate
Water flow through the heat exchange system, in a short period of time (<1h/day; <200h/year), the maximum flow rate of normal operation, the flow rate, the accuracy of the heat meter should not exceed the error limit.
3.15 cumulative flow Total volume
Total volume of water flowing through the heat meter.
3.16Temperature upper limit (tmax) The highest temperature
In the heat meter accuracy does not exceed the error limit, the maximum temperature that the water may reach.
3.17 temperature lower limit (tmin) The lowest temperature
In the heat meter accuracy does not exceed the error limit, the lowest temperature the water may reach.
3.18 Maximum admissible working pressure (MAP) Maximum admissible working pressure
In the upper limit of the temperature continues to work, the heat meter can withstand the maximum working pressure.
3.19Pressure loss
In a given flow rate, the value of pressure reduction caused by the heat meter.
3.20 Maximum admissible pressure lossMaximum admissible pressure loss
In the common flow rate qp, the water flow through the heat meter pressure loss limit value.
3.21 Maximum thermal powerMaximum thermal power
In the heat meter accuracy does not exceed the error limit, the maximum value of thermal power may reach.
4 technical characteristics
4.1 heat measurement
Installed in the heat exchange system of integral heat meter or combined heat meter, when the water flow through the system, according to the flow rate given by the flow sensor and paired with the temperature sensor given by the temperature of the supply and return water, as well as the time of the flow of water through the system through the calculator can be calculated and displayed the system released or absorbed heat. The basic formula is (1)
Q= q Δhd = ........................ ...............(1)
CJ 128-2000
The formula: Q- - heat released or absorbed (J or wh);
qm - mass flow rate of water flowing through the heat meter (kg/h);
qv - volume flow rate of water flowing through the heat meter ( m3 /h);
ρ--density of water flowing through the heat meter (kg/ m3);
Δh--difference in enthalpy of water at inlet and outlet temperatures of the heat exchange system (J/kg);
-- time (h).
Equation (1) in the density and enthalpy shall comply with the provisions of appendix A of this standard. When the temperature is a non-integer, interpolation should be corrected.
4.2 heat meter structure and materials
4.2.1 heat meter by the flow sensor, paired temperature sensor and calculator. Heat meter inlet should be equipped with a filter.
4.2.2 The heat meter should have a detection interface or data communication interface, the requirements of which are set out in Appendix G, but all interfaces shall not change the measurement characteristics of the heat meter.
4.2.3 The shell of the heat meter must be waterproof, dust intrusion.
4.2.4 Flow sensor materials, especially the rotating parts, should have sufficient mechanical strength and corrosion resistance, and in the water temperature conditions in Table 2 of this standard can work properly.
4.2.5 Temperature sensor structure and materials
4.2.5.1 Temperature measurement should be used platinum resistance temperature sensor, its structure and installation should be in accordance with the provisions of Appendix B. If the temperature sensor and the calculator is composed of one, can also use other forms of temperature sensors. Temperature sensors should be measured to select the pair.
4.2.5.2 Temperature sensor and pipe connection, should be used to seal the thread connection, thread specifications should be consistent with the relevant national standards.
4.3 Main Parameters
4.3.1 When the flow sensor is connected by thread, the connection dimensions and methods are shown in Table 1, Figure 1 and Figure 2. 40mm nominal diameter or less than 40mm nominal diameter (including 40mm), but the working pressure is greater than 1.6MPa, less than 2.5MPa flow sensor should be connected by flange, and the flange size should be in accordance with the provisions of GB9113. GB9113 provisions.
Table 1
Nominal diameter DN
Commonly used flow rate
qp (m3/h) Flow sensor interface dimensions (see Figure 1) Flow sensor receiver dimensions (see Figure 2)
Interface thread
D Thread length Receiver length
L1 (mm) Thread effective length
L2 (mm)
Thread D1
amin
(mm) bmin
(mm)
15
0.6 G B
10 12 45 14 R1/2
1.5
20 2.5 G1B 12 14 50 16 R3/ 4
25 3.5 G1 B
12 16 58 18 R1
32 6.0 G1 B
13 18 60 20 R1
40 10 G2B 13 20 62 22 R1
CJ 128-2000
4.3.2 Temperature and pressure
The heat meter is divided into two types according to the working conditions, see table 2.
Table 2
Type Temperature (℃) Pressure (MPa)
At room temperature 4～95 ≤ 1.6
High temperature 4～150 ≤2.5
4.3.3 Flow rate
The commonly used flow rate of heat meter should be conformed to the following standards GB/T778 cold water meter requirements, the lowest common flow rate of 0.6m3/h. The ratio of common flow rate and minimum flow rate should be 10, 25, 50 or 100. nominal diameter ≤ 40mm heat meter, the common flow rate and the minimum flow rate must be 50 or 100.
4.3.4 Temperature difference
The ratio of the maximum temperature difference of heat meter to the minimum temperature difference should be more than 10, the supplying manufacturer should use the ratio of the maximum temperature difference to the minimum temperature difference, the supplying manufacturer should use the ratio of the minimum temperature difference to the maximum temperature difference. The ratio of the maximum temperature difference to the minimum temperature difference should be greater than 10, the supplying manufacturer must provide the minimum temperature difference value, generally the minimum temperature difference can be 1 ℃, 2 ℃, 3 ℃, 5 ℃ and 10 ℃, but the nominal diameter of ≤ 40mm heat meter, Δtmin ≤ 3 ℃.
5 Technical Requirements
5.1 Ambient Temperature
Environmental Class A: +5 ℃ ~ +55 ℃
Environmental Class B: -25 ℃ ~ +55 ℃
5.2 Display Requirements
5.2.1 The heat meter displays at least the amount of heat, flow rate, cumulative flow rate, supply and return temperatures, and the cumulative operating time.
5.2.2 The display unit of heat must be J or wh and its ten times. Accumulated flow rate must be displayed in m3.
The display unit of temperature must be displayed in ℃. The display unit must be labeled in a position that is not to be confused.
5.2.3 The visible height of the display digits should not be less than 4mm, and the decimal digits must be separated by a decimal point.
5.2.4 The heat meter must be able to display the amount of heat under the maximum thermal power for 3000h without over-range. Work at the maximum thermal power for one hour, the minimum number of digits of the heat meter at least one step.
5.3 Performance requirements
5.3.1 Strength and sealing
Should be able to withstand the specified temperature and pressure of the hydraulic strength test and sealing test. Test results without leakage, no damage.
5.3.2 Measurement characteristics
Heat meter measurement accuracy is divided into three levels, using the relative error limit E, the relative error limit E is defined as follows:
CJ 128-2000
E= (2)
The formula: Vd -displayed measured value;
Vc-conventional true value.
Level 1 (note) E=±(2+4 +0.01 ) (3)
Level 2 E=±(3+4 +0.02 ) (4)
Level 3 E=±(4+4 +0.05 ) (5)
Equation : E- Relative Error Limit %;
Δ tmin--minimum temperature difference ℃;
Δt--temperature difference ℃ within the use range;
qp--Common flow rate m3/h;
< p>q - the use of the range of flow m3 / h.5.3.2.1 Integral calorimeter accuracy should be implemented in accordance with the above three levels.
5.3.2.2 Combined heat meter accuracy level can be implemented in accordance with the sub-parts of the error limit. The total error of the heat meter is the arithmetic sum of the three errors (absolute value and).
5.3.3 Calculator error limit E
E = ± (0.5 + ) (6)
5.3.4 Matching temperature sensor error limit E
E = ± (0.5 + 3) (7)
5.3.5 Flow sensor error limit E
1 level (note) E = ± (1 + 0.01) (8)
5.3.5 flow sensor error limit E
1 level (note) E = ± (1 + 0.01) (8)
5.3.5 Flow sensor error limit E
2 level (note) E = ± (1 + 0.01) (8) p>
Class 2 E = (2+0.02 ) (9)
Class 3 E = (3+0.05 ) (10)
CJ 128-2000
The flow sensor error limit for each class should not exceed a maximum of 5%.
Note: If the level 1 error limit can be measured and the level 1 flow sensor can be realized, then the level 1 E and Eq calculated according to the formula (3) and (8).
5.3.6 Maximum Allowable Pressure Loss
In the common flow rate, the maximum allowable pressure loss should not exceed 0.025MPa.
5.3.7 Power Requirements
5.3.7.1 Power supply for the calorimeter should be used with internal batteries, and the service life of the internal batteries should be more than 5 years.
5.3.7.2 External grid power supply voltage Vn = (220) V, frequency fn = (50 ± 1) Hz.
5.3.7.3 Replacement of the battery shall not damage the calibration mark of the calorimeter.
5.3.7.4 When the operating power supply is under voltage, it should be prompted.
5.4 Accelerated durability
Accelerated durability according to the provisions of Table 3.
Table 3
Item Test Conditions Remarks
Flow sensor At a temperature of tmax-5℃, the maximum flow rate of qmax, continuous operation of 300h. Accuracy error limit should be in accordance with the provisions of Article 5.3.5 of this standard.
Paired temperature sensor Temperature heating to the upper limit, and then down to the lower limit, repeat 10 times. Accuracy error limit shall comply with the provisions of article 5.3.4 of this standard.
Calculator in the maximum thermal power continuous operation of 500h. Accuracy error limits should be consistent with the provisions of Article 5.3.3 of this standard.
5.5 safety requirements
5.5.1 Power failure data protection
When the power supply stops, the heat meter should be able to save all the data, restore the power supply, able to restore the normal measurement function; power outage should have measures to measure or calculate the heat during the power failure.
5.5.2 Anti-magnetic interference
When interfered with by the magnet, it should not affect its measurement characteristics.
5.5.3 Enclosure protection
According to the provisions of GB4208, environment class A heat meter should have IP52 protection level, environment class B heat meter should have IP54 protection level.
5.5.4 Seal
The heat meter should be sealed reliably, and the heat meter can not be disassembled without destroying the seal.
5.5.5 Heat meter electrical insulation should be consistent with the provisions of GB4706.1.
5.6 Transportation Requirements
The meter should not be directly affected by rain, frost, fog during transportation after it is packed into the packing box according to the regulations, placed upward according to the sign, and not subject to extrusion, collision and other damage. Transportation of environmental conditions in accordance with the provisions of JB/T9329. The temperature range can be according to the heat
The table of the environmental class, such as environmental class A for +5 ℃ ~ 55 ℃; environmental class B for -25 ℃ ~ 55 ℃.
5.7 Calculator Operating Environment Requirements
Under the operating environment conditions specified in Table 4, the performance of the calculator should be unaffected.
CJ 128-2000
Table 4
Item Environmental Conditions
Dry thermal environment Temperature (55±2)°C, humidity not exceeding 20%.
Cooling environment Environment A: Temperature (5±3)℃, Environment B: Temperature (-25±3)℃.
Constant humidity and heat environment Temperature (40±2)℃, humidity not less than 93%.
Cycling humid-heat environment Temperature change from 25°C to 50°C, humidity not less than 93%, cycling 2 times.
Power supply voltage variation ①External power supply: the upper voltage limit is 1.1V, the lower voltage limit is 0.85V, and the frequency variation is (0.98-1.02) fn.
②Built-in battery: the upper voltage limit is the voltage of the battery when there is no load at 20℃, and the lower voltage limit is the minimum working voltage stipulated by the supplier.
Electromagnetic compatibility ① electrostatic discharge immunity should be in line with the provisions of GB/T17626.2, Chapter 5, test level 2, contact discharge 4kV, performance criteria:
a) test the heat meter function is temporarily reduced or lost, but it can be automatically restored;
b) the heat meter can not be any change in the program, the memory data can not be lost or changed.
② radio frequency electromagnetic field radiation immunity should be consistent with the provisions of Chapter 5 of GB/T17626.3, the test level 2, the test field strength of 3V/m, the frequency of 80 ~ 1000MHz.
6 Test Methods
6.1 Test room test conditions
Temperature range: 15 ℃ ~ 35 ℃;
Relative Humidity
Relative humidity: 25% to 75%;
Atmospheric pressure: 86 kPa to 106 kPa.
6.2 Test setup
6.2.1 Should be able to satisfy the metrological characteristics of the instrument under test, the error should be no greater than the tested instrument 1/5 of the test setup.
6.2.2 Flow sensor test device
Cold water test can be GB/T778.3 cold water meter test device, hot water test can be JB/T8802 hot water meter test device.
6.2.3 Calculator test device
A pulse generator for simulating the signal of the flow sensor. A standard resistor with an accuracy of 1 in 10,000 is used to simulate the resistance value of a platinum resistor at the corresponding test temperature. Can also be used through the measurement department recognized test device.
6.2.4 Temperature sensor test device
Temperature sensor test can be JB/T8622 test device.
6.3 Pressure test
6.3.1 Factory inspection should be in accordance with GB/T778.3 cold water meter part 3 of the test.
6.3.2 Type test should be tested in accordance with the provisions of JB/T8802, water temperature 55 ℃ ± 5 ℃.
6.3.3 The air in the test device and flow sensor should be excluded, the test device should be leak-proof, the pressure should be gradually increased to prevent sudden pressure increases
6.4 Calorimeter Accuracy Test
CJ 128-2000
The calorimeter accuracy test can be separately on the flow sensor, Temperature sensor and calculator performance test or the use of the measurement department recognized by the overall heat measurement device for the overall test.
6.4.1 flow sensor accuracy test
The test, the flow sensor upstream and downstream should be a straight section of the straight section length should be measured according to the requirements of the flow sensor. Flow sensor accuracy test and calculation according to the provisions of Appendix C.
6.4.2 Temperature sensor accuracy test
Temperature sensor accuracy test and calculation in accordance with the provisions of Appendix D.
6.4.3 Calculator accuracy test
The accuracy test and calculation of the calculator are performed according to Appendix E.
6.4.4 Calorimeter accuracy test and calculation
The accuracy test and calculation of the calorimeter is performed as specified in Appendix F.
6.5 Pressure loss test
Pressure loss test according to JB/T8802 standard. The flow rate is the common flow rate, the temperature is (55±5)℃, the pressure loss should meet the provisions of Article 5.3.6.
6.6 Accelerated durability test
Accelerated durability test of all parts of the heat meter according to the provisions of Table 3, the error limit should meet the provisions of 5.3.3 to 5.3.5.
6.7 Transportation condition test
The test method shall be conducted according to the provisions of JB/T9329.
6.8 Internal battery life test
Based on 80% of the rated capacity of the battery as a reference data, half a year of working conditions and half a year of dormant state of the heat meter measured the sum of the corresponding current to calculate the power consumption of the heat meter and the corresponding battery life.
6.9 Calculator environment test
6.9.1 Dry heat test: according to the environmental conditions in Table 4, according to the provisions of GB/T2423.2.
Simulated water temperature (55 ± 5) ℃, temperature difference of 1.1 Δtmin, flow rate of 1.1qmin; test samples to achieve temperature stability, the test time is 2h.
6.9.2 Cooling test, according to the environmental conditions in Table 4, according to the provisions of GB/T2423.1.
Simulated water temperature (55 ± 5) ℃, temperature difference of 1.1 Δtmin, flow rate of 1.1qmin; test samples to achieve temperature stability, the test time is 2h.
6.9.3 Constant humidity and heat test, according to Table 4 of the environmental conditions, according to the provisions of GB/T2423.3.
Simulated water temperature (55 ± 5) ℃, temperature difference of 1.1 Δtmin, flow rate of 1.1qmin; test time for the test samples to achieve temperature stabilization after 2h.
6.9.4 Cyclic hygrothermal test, according to Table 4 of the environmental conditions, according to the provisions of GB/T2423.4.
Simulated water temperature (55 ± 5) ℃, temperature difference 1.1 Δtmin, flow rate of 1.1qmin; 12h for 1 cycle, the number of cycles is 2.
6.9.5 Voltage change test
6.9.5.1 Power supply voltage change test
The test is carried out in accordance with the conditions in Table 4, the simulated water temperature (55 ± 5) ℃, the difference in temperature 1.1Δtmin, temperature difference 1.1Δtmin, temperature difference 1.1Δtmin, flow rate of 2h after 2h. 1.1Δtmin, flow rate 1.1qmin, and meet the provisions of 5.7.
6.9.5.2 Battery voltage change test
Tested according to the conditions in Table 4, simulated water temperature (55 ± 5) ℃, temperature difference of 1.1 Δtmin, flow rate of 1.1qmin, and meet the provisions of 5.7.
CJ 128-2000
6.9.6 Electromagnetic compatibility test
6.9.6.1 Radiofrequency electromagnetic field radiation immunity test
Tested in accordance with the provisions of GB/T17626.3, and the test should meet the provisions of 5.7.
6.9.6.2 Electrostatic discharge immunity test
Discharge can be applied to any surface of the heat meter, usually the user can access the surface, the contact discharge voltage is 4kV, discharge mode is a single click, the number of 10 times. The discharge electrode is held close to the heat meter until a discharge occurs. Remove the electrode before the next discharge. Continuous discharge time interval should be greater than 10s, the test is carried out in accordance with the provisions of GB/T17626.2?
The flow rate is 0 during the test, and the provisions of 5.7 shall be satisfied after the test.
6.10 monitor test
Measurement of the height of each display symbol should not be less than 4mm;
Visual display shows the unit of heat, with J, wh or its decimal multiples;
Visual display shows the cumulative flow rate of the unit, with m display;
Visual display shows the unit of medium temperature, with ℃ display;
Visual demonstration of the measurement parameters to meet the provisions of 5.2.1.
6.11 Safety Requirements Detection
6.11.1 Power Failure Protection Function Detection
When the power supply is interrupted, the heat meter saves all the data and records the time of interruption. When the fault is removed, the heat meter automatically restores the function.
6.11.2 Seal protection function detection
Visually inspect the seal protection of all removable parts affecting metering.
6.11.3 Anti-magnetic protection function test
The heat meter under normal working conditions, the flow sensor, calculator shell and the display placed in the magnetic field strength of 100kA / m environment, the display during the monitoring period of the indicator value can not occur intermittent and sudden acceleration and deceleration phenomenon.
6.11.4 Visual inspection of the shell protection level sign, to meet the requirements of 5.5.3.
6.11.5 Calorimeter electrical insulation level test should be carried out in accordance with the provisions of GB4706.1.
7 inspection rules
7.1 Inspection classification
Heat meter inspection is divided into factory inspection and type inspection.
7.2 Factory inspection
Heat meter factory inspection should be carried out by the manufacturer's inspection department, and sign the certificate of conformity before leaving the factory.
7.3 Type Inspection
The heat meter in the following cases shall be type inspection:
a) when the production materials, processes and product structure changes, affecting product quality;
b) resumption of production after a one-year suspension of production;
c) normal production, every three years shall be a type inspection.
7.4. Group batch and sampling
7.4.1 heat meters should be submitted to the test in batches, each batch should be the same model, the same process state of the production of heat meters.
7.4.2 Dimensional acceptance of the sampling and pass level according to the provisions of GB2828.
7.4.3 Performance test acceptance
The test items of factory inspection and type inspection shall be carried out in accordance with the provisions of Table 5;
CJ 128-2000
The factory inspection shall be carried out on a meter-by-meter basis, and all the items shall be considered qualified when they are qualified;
The type inspection shall be carried out in accordance with the provisions of GB/T2829. The provisions of the sampling and judgment.
Table 5 Test Item List
Serial No. Technical Requirements Corresponding Clause Factory Inspection Type Inspection
1 Display Requirements 5.2 √ √
2 Strength and Sealing 5.3.1 √ √
3 Accuracy of Heat Meter 5.3.2 √ √
4 Accuracy of Calculator 5.3.3 √ √
5 Pairing Temperature Sensor Accuracy 5.3.4 √ √
6 Flow Sensor Accuracy 5.3.5 √ √
7 Maximum Allowable Pressure Loss 5.3.6 × √
8 Power Requirements 5.3.7 √ √ √
9 Accelerated Durability 5.4 × √ √
10 Safety Requirements 5.5 √ √
11 Shipping Requirements 5.6 × √ √
12 Requirements for the operating environment of the calculator 5.7 × √ √
The √s in Table 5 indicate the items that are required to be tested, and the ×s indicate the items that are not required to be tested.
7.5 Unqualified provisions
If the test results are unqualified, you can double the re-sampling, re-examination of unqualified items, such as the re-examination results in line with the provisions of this standard, the batch of products qualified. If still unqualified, the batch of products failed.
8 Signs, packaging and storage
8.1 Signs
8.1.1 The flow sensor must be marked with an arrow on the direction of water flow.
8.1.2 The sign of each heat meter can be made into a sign, fixed in the obvious position of the meter body.
The signage should include the following:
--Manufacturer's name, trademark and factory number;
--Product name, model number, flow rate range, temperature range, temperature difference range, pressure rating, accuracy level
--Ambient temperature category;
--Manufacture of measuring instruments license sign, number.
8.2 Product Packaging
Packaging box according to the provisions of GB191 printed on the outside of up, moisture, be careful to put signs. And marked with the name of the factory address, measuring instruments license sign, number, net weight and manufacturing date (or number).
Random documents in the box are:
--Product certification;
--Instruction manual;
--Packing list.
8.3.3 Storage environmental conditions
CJ 128-2000
8.3.1 The product cushion is at least 30cm from the ground, and the distance from the four walls should be not less than 1m, and the distance from the heating equipment should be not less than 2m.
8.3.2 Provisions of the environmental conditions of the warehouse
Environmental category A: ＋5 ℃ ～＋55℃;
Environmental category B: -25℃～＋55℃;
Relative humidity: less than 80%;
Warehouses should be free of acid, alkali, flammable, explosive, poisonous and other chemicals, and other corrosive gases and substances.
Strong electromagnetic field effect and direct sunlight should be prevented.
CJ 128-2000
Appendix A (appendix to the standard)
Table of density and enthalpy of water
A1 When the working pressure ≤ 1.0MPa, the density and enthalpy of water should be used in Table A1.
Table A1 P = 0.6000MPa, the temperature of 1°C -Table of density and enthalpy of water at 150℃
Temperature (℃) Density (kg/ m3) Enthalpy (kJ/kg) Temperature (℃) Density (kg/ m3) Enthalpy (kJ/kg)
1 1000.2 4.7841 51 987.80 214.03 101 957.86 423.76
2 1000.2 8.9963 52 987.33 218.21 102 957.14 427.97
3 1000.2 13.206 53 986.87 222.39 103 956.41 432.19
4 1000.2 17.412 54 986.39 226.57 104 955.67 436.41
5 1000.2 21.616 55