GB/T 35974.5-2018 English PDF (GBT35974.5-2018)

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GB/T 35974.5-2018: Plastics and plastic lining pressure vessels -- Part 5: Fabrication, inspection and testing for pressure vessels with plastic lining
GB/T 35974.5-2018
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 71.120; 83.140
G 94
Plastics and Plastic Lining Pressure Vessels -
Part 5: Fabrication, Inspection and Testing for
Pressure Vessels with Plastic Lining
塑料及其衬里制压力容器
ISSUED ON: FEBRUARY 6, 2018
IMPLEMENTED ON: SEPTEMBER 1, 2018
Issued by: General Administration of Quality Supervision, Inspection and
Quarantine;
Standardization Administration of the People’s Republic of
China.
Table of Contents
Foreword ... 3 
1 Scope ... 4 
2 Normative References ... 4 
3 Fabrication ... 4 
4 Technical Requirements ... 9 
5 Inspection ... 10 
6 Exit-factory Requirements ... 14 
Plastics and Plastic Lining Pressure Vessels - Part 5:
Fabrication, Inspection and Testing for Pressure
Vessels with Plastic Lining
1 Scope
This Part of GB/T 35974 specifies the fabrication, technical requirements, testing and
exit-factory requirements of pressure vessels with plastic lining.
This Part is applicable to pressure vessels with plastic lining, which are fabricated
through the processing procedures of welding, rotational molding and winding sintering.
2 Normative References
The following documents are indispensable to the application of this Standard. In terms
of references with a specified date, only versions with a specified date are applicable
to this Standard. In terms of references without a specified date, the latest version
(including all the modifications) is applicable to this Standard.
GB/T 150.4 Pressure Vessels - Part 4: Fabrication, Inspection and Testing, and
Acceptance
GB/T 35974.2 Plastics and Plastic Lining Pressure Vessels - Part 2: Materials
GB/T 35974.3 Plastics and Plastic Lining Pressure Vessels - Part 3: Design
HG/T 4090 Spark Test Method for Equipment Lined with Plastics
HG/T 4092 Expansion and Contraction Test Method for Equipment Lined with Plastics
HG/T 4093 Vacuum Test Method for Equipment Lined with Plastics
HG/T 4280 Welding Procedure Qualification for Plastics
HG/T 4281 Welding Procedure Specification for Plastics
JB/T 4711 Coating and Packing for Pressure Vessels Transport
NB/T 47013.8 Nondestructive Testing of Pressure Equipment - Part 8: Leak Testing
3 Fabrication
3.1 General Requirements
internal surface of the shell. Heat the rotating shell. The setting of heating temperature
and time shall satisfy the requirements of the processing procedures. The highest air
heating temperature in the shell shall be not lower than 180 °C.
3.3.2.1.3 Cooling
Cool down the shell that is already heated. During the cooling process, the shell shall
maintain the rotatory state. One of the following cooling modes, or a combination of
several cooling modes may be adopted for cooling: natural cooling, water mist cooling
or water spray cooling. During the cooling process, the difference between the air
temperature in the shell and the external surface temperature of the shell shall not
exceed 40 °C. When the external surface temperature of the shell decreases to 50 °C
~ 80 °C, stop the rotation of the shell.
3.3.2.1.4 Post-processing
After the shell cools down to room temperature, adopt vibration method to eliminate
the internal stress of the lining-layer plastics.
3.3.2.2 Procedure evaluation
Procedure evaluation shall at least include the items listed in Table 1. The various item
indexes shall comply with the designed value and the stipulations in GB/T 35974.2.
3.3.3 Winding sintering
3.3.3.1 Methods
3.3.3.1.1 Bar stock preparation
Use 20-mesh sieve to sieve powdered resin, so that it would be in a loose state. Evenly
add it into steel mold. Use a scraping cutter to make it flat. On a pressing machine,
compact it, then, slowly add pressure, so that air would be exhausted. After demolding,
place it on a sintering furnace to start heating, plasticization and sintering. Sintering
temperature shall be controlled at 380 °C  5 °C. Moreover, maintain the temperature,
till it reaches a translucent state. Cool it down in the furnace, till it reaches the room
temperature, then, take out the bar stock.
3.3.3.1.2 Thin strip processing
Use a lathe to cut the bar stock into thin strips at the width of 20 mm ~ 30 mm; wind
and organize it into coils.
3.3.3.1.3 Winding
Wind the thin strips on an appropriate mold. After reaching the stipulated thickness,
wind 3 layers ~ 4 layers of alkali-free glass ribbon. During the wrapping, properly
tighten it; the various parts shall receive uniform stress.
Hot and cold cycle test of lining vessels shall be conducted in accordance with the
numerical value stipulated in HG/T 4092. Lining shall not manifest phenomena like
deformation or cracks.
4.7 Negative Pressure Resistance Test
Lining negative pressure test shall be conducted in accordance with HG/T 4093. Lining
shall not manifest phenomena like distortion, flattening, deformation or cracks. At
normal temperature, negative pressure resistance value shall take 80% of the failure
value as the safe service value.
5 Inspection
5.1 Inspection Methods
5.1.1 Appearance
Under the condition that illuminance is not less than 750 lx, adopt the mode of visual
inspection to inspect the appearance.
5.1.2 Minimum wall thickness of lining
Use a thickness gauge, whose accuracy is not less than 0.02 mm, to measure the
minimum wall thickness of lining.
5.1.3 Pressure resistance test
5.1.3.1 External shell safety test of lining vessels
External shell safety test of lining vessels shall be conducted in accordance with the
methods stipulated in GB/T 150.4. Test temperature shall be normal temperature.
Pressure resistance test may select one of the following methods: hydraulic test, gas
pressure test and gas-liquid combined pressure test.
Generally speaking, in hydraulic test and gas-liquid combined pressure test, liquid is
water. In gas pressure test and gas-liquid combined pressure test, gas shall be dry and
clean air, nitrogen or other inert gas.
When hydraulic test is adopted, test pressure shall be determined in accordance with
Formula (1). Maintain the pressure for 30 min.
When gas pressure test and gas-liquid combined pressure test are adopted, test
pressure shall be determined in accordance with Formula (2). Maintain the pressure
for 10 min. The test shall have safety protection measures.
When it is stipulated in design documents, comply with the methods and requirements
stipulated in design documents. There shall be safety protection measures in the test.
After lining vessels are qualified in the shell safety test, and the lining is completed,
leakage test of lining vessels may be conducted. Lining vessels which are qualified in
gas pressure test may not need air tightness test in the leakage test.
5.1.4.2 Air tightness test
Air tightness test shall be conducted in accordance with the methods stipulated in GB/T
150.4. Test temperature shall be normal temperature. Test pressure shall be
determined in accordance with Formula (3). Maintain the pressure for 10 min.
5.1.4.3 Helium leak detection
In accordance with the methods stipulated in NB/T 47013.8, conduct helium leak
detection. Test temperature shall be normal temperature. The maximum test pressure
shall not exceed 1.15 times of the design pressure. Maintain the pressure for 30 min.
During the helium leak detection process, negative pressure is not allowed to emerge.
5.1.5 Electric spark test
Electric spark test parts are the whole internal surface of lining ...