GB/T 34530.2-2017 PDF English
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Valve for cryogenic insulated cylinder -- Part 2: Shut-off valve
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GB/T 34530.2-2017: PDF in English (GBT 34530.2-2017) GB/T 34530.2-2017
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 23.020.30
J 74
Valve for cryogenic insulated cylinder -
Part 2: Shut-off valve
ISSUED ON: OCTOBER 14, 2017
IMPLEMENTED ON: MAY 01, 2018
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 Basic type ... 5
4 Technical requirements ... 6
5 Test methods ... 8
6 Inspection rules ... 15
7 Marking, packaging, transportation, storage ... 17
8 Product certificate, quality certificate of product batch inspection ... 18
Foreword ... 3
1 Scope ... 4
2 Normative references ... 4
3 Basic type ... 5
4 Technical requirements ... 6
5 Test methods ... 8
6 Inspection rules ... 15
7 Marking, packaging, transportation, storage ... 17
8 Product certificate, quality certificate of product batch inspection ... 18
Valve for cryogenic insulated cylinder -
Part 2: Shut-off valve
1 Scope
This part of GB/T 34530 specifies the basic types, technical requirements, test
methods, inspection rules, marking, packaging, transportation, storage, product
certificate, batch inspection quality certificate of shut-off valves for cryogenic
insulated cylinders (hereinafter referred to as “valves”).
This part applies to the shut-off valve for gas cylinders which contain mediums
such as liquid oxygen, liquid nitrogen, liquid argon, liquefied natural gas, carbon
dioxide, nitrous oxide, have a nominal working pressure of not more than 3.5
MPa, the design temperature of -196 °C ~ +85 °C, the ambient temperature of
-40 °C ~ +60 °C.
2 Normative references
The following documents are indispensable for the application of this document.
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 228.1 Metallic materials - Tensile testing - Part 1: Method of test at
room temperature
GB/T 4423 Copper and copper-alloy cold-drawn rod and bar
GB/T 5231 Designation and chemical composition of wrought copper and
copper alloys
GB/T 15382 General technical requirements for valves of gas cylinders
JB/T 6896-2007 Surface clearness of air separation plant
YS/T 482 Methods for analysis of copper and copper alloys - The atomic
emission spectrometry
4 Technical requirements
4.1 Material requirements
4.1.1 General requirements
The material of the valve shall comply with the following requirements:
a) At the design temperature, the texture structure of the material shall be
stable; it shall not cause deformation and brittle failure due to phase
change of the material;
b) The material shall meet the compatibility requirements of the medium as
contained in the cylinder;
c) The selection of materials for movable metal parts shall avoid the
phenomenon of jamming, occlusion, or scratches due to frequent
movements;
e) The materials of non-metallic seal shall have good low-temperature
resistance. It shall not use rubber seal materials. If used to contain oxygen
or oxidizing gas, it should use fluoroplastics.
4.1.2 Valve material
The valve material should adopt HPb59-1 lead brass. Its mechanical properties
and chemical composition shall meet the requirements of GB/T 4423 and GB/T
5231. When using other materials, the mechanical properties shall not be lower
than the requirements of HPb59-1.
4.1.3 Non-metallic sealing materials
4.1.3.1 Resistance to oxygen aging
After being continuously placed in an oxygen (purity ≥ 99.5%) which has a
temperature of 70 °C ± 2 °C and a pressure of 2 MPa for 96 hours, when
checking in a magnifying glass of 25x, there shall be no crack.
4.1.3.2 Compatibility of liquefied natural gas medium
For the non-metallic sealing material for liquefied natural gas medium, immerse
it in n-pentane at a temperature of 25 °C ± 3 °C for 72 h; the volume change
rate shall be not more than 20%. Then place it in air at 40 °C ± 3 °C for 48 h,
the mass change rate shall be not more than 5%.
4.2 Design and process requirements
4.2.1 The connection form and size of the air inlet and outlet shall meet the
Take the average of the three samples as the test results, which shall meet the
requirements of 4.1.3.2.
5.4 Visual inspection
The appearance of the valve shall be checked by visual inspection. The results
shall comply with the provisions of 4.2.4 and 7.1.
5.5 Inspection of connection size of air inlet and outlet
The size of the air inlet and outlet of the valve shall be inspected by a gage that
meets the tolerance grade of the size. The inspection result shall meet the
corresponding tolerance requirements of the size.
5.6 Test of pressure resistance
Mount the valve on the test device. Plug the vent hole of the valve to outside.
Connect the air inlet of the valve to the hydraulic pressure test stand. Fill in
clean tap water. Slowly raise the pressure to 5 times the nominal working
pressure. Hold the pressure for 5 min. It shall comply with the provisions of
4.3.1.
5.7 Opening and closing test
Install the valve in the liquid phase outlet of the liquid nitrogen cylinder. The
pressure in the cylinder is 0.5 times the nominal working pressure. From the air
inlet of the valve, fill the liquid nitrogen for continuous 1 min. Then use the
operating torque of not more than 7 N • m to close the valve. There shall be no
leakage until the valve restores to ambient temperature. Then use the torque of
not more than 7 N • m to open the valve. The valve shall be able to be opened
smoothly. For the valve which passes the above tests, use the torque of 25 N •
m to close the it. The result shall meet the requirements of 4.3.2 b).
5.8 Test of air-tightness
5.8.1 Test of air-tightness at ambient temperature
In the ambient temperature of 15 °C ~ 30 °C, install the valve on the test device.
Close the valve. From the air inlet of the valve, fill in nitrogen or air to 1.2 times
the nominal working pressure. Immerse the valve in water and hold pressure
for at least 1 min. It shall comply with the requirements of 4.3.3. Open the valve.
The gas shall flow out smoothly.
Block the air outlet of the valve. Open the valve. From the air inlet of the valve,
fill in nitrogen or air to 1.2 times the nominal working pressure. Immerse the
valve in water and hold pressure for at least 1 min. It shall comply with the
requirements of 4.3.3.
Ps - The initial pressure, in Megapascal (MPa);
Pf - The final pressure, in Megapascal (MPa).
5.8.3.1.2 Test of external airtightness at low-temperature
After measuring Vd, follow the steps below to test the external leakage of valve:
a) Close the valves V-2, V-3; open the valves V-1, V-4, so that the tested
valve R-1 is in any open state. Use helium to purge the test device;
b) Close the valve V-4. Fill in the helium gas to the nominal working pressure.
Close the valve V-1. After the pressure is stable, record the ambient
temperature Z and the pressure P1 at this time;
c) Immerse the tested valve R-1 in liquid nitrogen, at a depth such that the
air inlet and outlet of valve are below the level of liquid nitrogen;
d) After the temperature of the tested valve R-1 is stabilized, keep 0.01 Vd
hours. Then remove the tested valve R-1 from the liquid nitrogen;
e) Restore the test device to the ambient temperature Z again. Record the
pressure P2 at this time.
The pressure difference between the two is the leakage rate of the valve, which
shall comply with the provisions of 4.3.3.
5.8.3.2 Test of internal airtightness at low-temperature
The test of internal airtightness at low-temperature is carried out as follows:
a) As shown in Figure 3, install the tested valve R-1 on the test device. Close
the valves V-2, V-3;
b) Open the valve V-1. Fill the helium gas to the nominal working pressure.
Immerse the tested valve R-1 in liquid nitrogen, at a depth to allow the air
inlet and outlet of valve to be below the level of liquid nitrogen. Wait for
the temperature of the tested valve R-1 and the temperature of liquid
nitrogen to be stable;
c) Use a torque of not more than 11.3 N • m to close the tested valve R-1;
d) Open the valve V-3 to empty the gas in the pipeline;
e) After the temperature of the pipeline is stable, as shown in Figure 3,
connect the rear end of the valve V-3 to the bubble-collecting side-leakage
device (inverted measuring cup);
f) Hold for more than 1 min. Record the time T. Meanwhile record the
Install the valve on the service life testing machine. At the test temperature of
85 °C, from the air inlet of the valve, fill in the air to the nominal working pressure.
Use the torque of not more than 7 N • m to make 200 times whole-course
opening-closing at the rate of not more than 6 times/min. At ambient
temperature, connect the air inlet of the valve to the liquid outlet of the liquid
nitrogen cylinder. From the air inlet of the valve, fill in 2 MPa liquid nitrogen. Use
the torque of not more than 7 N • m to make 4000 times whole-course opening-
closing at the rate of not more than 6 times/min. Carry out test according to the
provisions of 5.8.1. The results shall comply with the provisions of 4.3.5.
5.11 Test of resistance to salt spray corrosion
Place the valve in a salt spray chamber at 33 °C ~ 36 °C. Block the air inlet and
outlet of the valve. Under the conditions where there is no shield, use a solution
which consists of 5% sodium chloride and 95% distilled water (mass), to
continuously carry out 96 h salt spray test. Then remove it. Immediately rinse
the specimen. Gently wipe off the surface deposit. Then follow the requirements
of 5.8.1 to carry out corresponding test. The results shall comply with the
provisions of 4.3.6.
5.12 Test of resistance to stress corrosion
Remove the grease from the valve. Tighten the plugs on the air inlet and outlet
of the valve (it shall not use Teflon tape or sealant on the threads). Pour 600 mL
of ammonia water which has a relative density of 0.94 (mass) into a 30 L capped
glassware. Place the valve on a plastic tray 40 mm above the level of the
ammonia solution. Place the glassware in a high-temperature box at a
temperature of 34 °C ± 2 °C for 24 h. The results shall meet the requirements
of 4.3.7.
6 Inspection rules
6.1 Inspection of raw materials
6.1.1 The enter-factory materials and parts shall have a quality certificate.
6.1.2 The valve material shall, based on batches of materials, be subjected to
enter-factory re-inspection of mechanical properties and chemical composition.
6.2 Exit-factory inspection
6.2.1 One-by-one inspection
The valve shall be inspected one by one before exit-factory. The inspection
items shall be as specified in Table 2. In the course of inspection, if one item
fails, the valve is unqualified.
......
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.
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