GB/T 18443.5-2010 English PDF (GBT18443.5-2010)

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GB/T 18443.5-2010: Testing method of performance for vacuum insulation cryogenic equipment - Part 5: Static evaporation rate measurement
GB/T 18443.5-2010
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 23.020
J 74
Replace GB/T 18443.5-2001
Testing method of performance for vacuum insulation
cryogenic equipment - Part 5.Static evaporation rate
measurement
ISSUED ON. SEPTEMBER 26, 2010
IMPLEMENTED ON. FEBRUARY 1, 2011
Issued by. General Administration of Quality Supervision, Inspection and
Quarantine of PRC;
Standardization Administration of PRC.
Table of Contents
Foreword... 3
1 Scope... 5
2 Normative references... 5
3 Terms and definitions... 6
4 Test principle and method... 6
5 Test devices, equipment, and instruments... 7
6 Test conditions and test preparation... 8
7 Test steps... 8
8 Data processing... 9
9 Test records and test reports... 13
Appendix A (Informative) Static evaporation rate test record (flowmeter method)... 14
Appendix B (Informative) Static evaporation rate test record (weighing method)... 15
Appendix C (Informative) Physical data of nitrogen... 16
Appendix D (Informative) Static evaporation rate test report... 17
Testing method of performance for vacuum insulation
cryogenic equipment - Part 5.Static evaporation rate
measurement
1 Scope
This part of GB/T 18443 specifies the requirements of the test principle and method,
test equipment, equipment and instruments, test conditions and test preparations, test
procedures, data processing, test records, and test reports for the measurement of the
static evaporation rate of vacuum insulated cryogenic equipment.
This part applies to the measurement of the static evaporation rate of vacuum insulated
cryogenic equipment, such as vacuum insulated cryogenic pressure vessels except for
the storage and transportation of liquid hydrogen medium, and vacuum insulated
cryogenic gas cylinders; the measurement of other equipment can be implemented by
reference.
2 Normative references
The provisions in the following documents become the provisions of this Part through
reference in this Part of GB/T 18443.For the dated references, the subsequent
amendments (excluding corrections) or revisions do not apply to this Part, however,
parties who reach an agreement based on this Part are encouraged to study if the latest
versions of these documents are applicable. For undated references, the latest edition of
the referenced document applies to this Part.
GB/T 18443.1 Testing method of performance for vacuum insulation cryogenic
equipment - Part 1.Basic requirements
GB/T 18443.2 Testing method of performance for vacuum insulation cryogenic
equipment - Part 2.Vacuum degree measurement
GB/T 18443.3 Testing method of performance for vacuum insulation cryogenic
equipment - Part 3.Leak rate measurement
GB/T 18443.4 Testing method of performance for vacuum insulation cryogenic
equipment – Part 4.Leak-outgassing rate measurement
3 Terms and definitions
The terms and definitions established in GB/T 18443.1~GB/T 18443.4 and the
following apply to this part.
3.1 Percentage loss of product per day
The percentage of the mass of cryogenic liquid lost by natural evaporation within 24 h
over the mass of cryogenic liquid that is corresponding to the effective volume of the
inner pressure vessel, after the cryogenic storage and transportation equipment stands
and reaches the thermal equilibrium at the rated fullness rate; the unit is percentage per
day (%/d).
4 Test principle and method
4.1 Test principle
Use a volume flowmeter or mass flowmeter to measure the natural evaporation of
cryogenic liquid per unit time, or use a weighing method to measure the loss of
cryogenic liquid per unit time.
4.2 Test method
4.2.1 Use the wet gas flowmeter to measure the gas flow passing through the flowmeter
after the liquid in the measured piece evaporates within a unit of time, and calculate the
Percentage Loss of Product per Day and the static evaporation rate with the measured
gas flow. The schematic diagram of the test device is shown in Figure 1.
4.2.2 Use the gas mass flowmeter to measure the gas mass flow passing through the
mass flowmeter after the liquid in the measured piece evaporates within a unit of time,
and calculate the Percentage Loss of Product per Day and static evaporation rate with
the measured gas mass flow. The schematic diagram of the test device is shown in
Figure 2.
4.2.3 When the effective volume of the measured piece is not more than 5 m3, it is
allowed to use the weighing method to measure. When the weighing method is used for
measurement, after the measured piece is charged to the rated filling quantity, place the
measured piece on the weighing instrument, and measure the mass of the cryogenic
liquid evaporated in the vacuum insulated cryogenic equipment with the weighing
instrument. Use the evaporation measured with the weighing method to calculate the
Percentage Loss of Product per Day and static evaporation rate.
a) When the range of the flowmeter is less than or equal to 5L/min, the accuracy
needs to reach 0.5%; when the range is greater than 5 L/min, the accuracy needs
to reach 1.0%;
b) The rated flow of the flowmeter shall be compatible with the gas flow evaporated
by the measured piece;
c) There shall be ambient temperature, ambient pressure, and flowmeter inlet
temperature and pressure measurement devices;
d) The maximum weighing of the weighing instrument used in the weighing method
shall be 1.2~2.0 times the full load mass of the measured piece, and its accuracy
shall meet the following requirements.
--- When the maximum weighing of the weighing instrument is 5T≤t< 10T, its
allowable deviation shall not exceed 1 kg;
--- When the maximum weighing of the weighing instrument is 3T≤t< 5T, its
allowable deviation shall not exceed 0.5 kg;
--- When the maximum weighing of the weighing instrument is 1T≤t< 3T, the
allowable deviation shall not exceed 0.2 kg;
--- When the maximum weighing of the weighing instrument is t< 1T, its
allowable deviation shall not exceed 0.1 kg.
6 Test conditions and test preparation
Test conditions and test preparations shall comply with the provisions of GB/T 18443.1.
7 Test steps
7.1 Flowmeter method
7.1.1 Liquid nitrogen is generally used as the test medium.
7.1.2 During measurement, the fullness rate of cryogenic liquid shall be the rated
fullness rate.
7.1.3 After the liquid filling is completed, it shall be standing for at least 48h. During
the standing period, the venting valve of the vacuum insulated cryogenic equipment
shall be opened.
7.1.4 When the gauge pressure of the inner liner is close to zero, connect the flowmeter
to the venting pipeline. After the flowmeter is connected, except the venting valve is
opened, the other valves of the measured piece shall be all closed.
7.1.5 After the flow of evaporated gas is stabilized, collect and record the indicated
value of the flowmeter, ambient temperature, atmospheric pressure, flowmeter inlet
temperature and pressure with a time interval that shall not be more than 1 h; the data
recording time shall be 24 h.
7.1.6 Calculate the static evaporation rate of the measured piece and compare it with
the static evaporation rate of the previous 24 h. When the variation range of the static
evaporation rate is less than 5%, the recorded data is valid; when the variation range of
the static evaporation rate is greater than 5%, it is allowed to record the data once again;
the recording time shall not be less than 24 h, and the data are final record data.
7.2 Weighing method
7.2.1 Except for special requirements, the test medium shall be liquid nitrogen.
7.2.2 During measurement, the cryogenic liquid fullness rate shall be rated fullness rate.
7.2.3 After the liquid filling is completed, it shall be standing for 48 h before the start
of recording data. During the standing period, the venting valve of the vacuum insulated
cryogenic equipment shall be opened.
7.2.4 When the gauge pressure of the inner liner is close to zero, except the venting
valve is opened, the other valves of the measured piece shall be all closed; record the
initial data of the weighing instrument at the same time.
7.2.5 Record the data of the weighing instrument when the time interval is 24 h and 48
h.
8 Data processing
8.1 Percentage loss of product per day α0
8.1.1 When the wet gas flowmeter is used for measurement, the percentage loss of
product per day α0 is calculated according to formula (1).
Where.
α0 --- The percentage loss of product per day, and the unit is percentage per day (%/d);
qv --- The daily average value of volume flow of evaporated gas, in cubic meters per
Where.
α0 --- The percentage loss of product per day, and the unit is percentage per day (%/d);
qg --- The mass of gas evaporated within 24 hours, in kilograms per day (kg/d);
ρ1 --- The density of the saturated liquid at standard atmospheric pressure (101.325
kPa), in kilograms per cubic meter (kg/m3);
V --- The effective volume of the measured piece, in cubic meters (m3).
8.2 Calculation of static evaporation rate
8.2.1 The static evaporation rate of high vacuum multilayer insulation α20 is calculated
according to formula (4).
Where.
α20 --- The static evaporation rate, and the unit is percentage per day (%/d);
α0 --- The percentage loss of product per day, and the unit is percentage per day (%/d);
h --- The latent heat of vaporization of the saturated liquid at test ambient pressure,
in kilojoules per kilogram (kJ/kg);
hfg --- The latent heat of vaporization of the saturated liquid at standard atmospheric
pressure (101.325 kPa), in kilojoules per kilogram (kJ/kg);
Ts --- The temperature of the saturated liquid at standard atmospheric pressure
(101.325 kPa), and the unit is Kelvin (K);
T1 --- The daily average ambient temperature during the test, and the unit is Kelvin
(K);
T2 --- The saturation temperature of the cryogenic liquid that is corresponding to the
daily average pressure in the measured piece during the test, and the unit is
Kelvin (K).
8.2.2 The static evaporation rate α20 of the vacuum insulation of the powder or fiber is
calculated according to formula (5).
Where.
α20 --- The static evaporation rate, and the unit is percentage per day (%/d);
α0 --- The percentage loss of product per day, and the unit is percentage per day (%/d);
h --- The latent heat of vaporization of the saturated liquid at test ambient pressure,
in kilojoules per kilogram (kJ/kg);
hfg --- The latent heat of vaporization of the saturated liquid at standard atmospheric
pressure (101.325 kPa), in kilojoules per kilogram (kJ/kg);
Ts --- The temperature of the saturated liquid at standard atmospheric pressure
(101.325 kPa), and the unit is Kelvin (K);
T1 --- The daily average ambient temperature during the test, and the unit is Kelvin
(K);
T2 --- The saturation temperature of the cryogenic liquid that is corresponding to the
daily average pressure in the measured piece during the test, and the unit is
Kelvin (K).
8.2.3 The static evaporation rate α20 of high vacuum insulation is calculated according
to formula (6).
Where.
α20 --- The static evaporation rate, and the unit is percentage per day (%/d);
α0 --- The percentage loss of product per day, and the unit is percentage per day (%/d);
h --- The latent heat of vaporization of the saturated liquid at test ambient pressure,
in kilojoules per kilogram (kJ/kg);
hfg --- The latent heat of vaporization of the saturated liquid at standard atmospheric
pressure (101.325 kPa), in kilojoules per kilogram (kJ/kg);
Ts --- The temperature of the saturated liquid at standard atmospheric pressure
(101.325 kPa), and the unit is Kelvin (K);
T1 --- The daily average ambient temperature during the test, and the unit is Kelvin
(K);