GB/T 34530.2-2017 English PDF (GBT34530.2-2017)

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GB/T 34530.2-2017: Valve for cryogenic insulated cylinder -- Part 2: Shut-off valve
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, ke...