Skip to product information
1 of 8

PayPal, credit cards. Download editable-PDF & invoice in 1 second!

GB/T 9251-2011 English PDF (GBT9251-2011)

GB/T 9251-2011 English PDF (GBT9251-2011)

Regular price $125.00 USD
Regular price Sale price $125.00 USD
Sale Sold out
Shipping calculated at checkout.
Delivery: 3 seconds (Download full-editable-PDF + Invoice).
Newer version: (Replacing this standard) GB/T 9251-2022
Quotation: Click GB/T 9251-2011>>Add to cart>>Quote
Editable-PDF Preview (Reload if blank, scroll for next page)

GB/T 9251-2011: Methods for hydrostatic test of gas cylinders
This Standard specifies the basic requirements for test methods and test devices for hydrostatic test of gas cylinders. This Standard applies to the hydraulic test of steel seamless gas cylinders, welded gas cylinders, aluminum alloy seamless gas cylinders and wound gas cylinders. This Standard does not apply to industrial non-refillable steel cylinders and gas cylinders filled with solid fillers.
GB/T 9251-2011
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 23.020.30
J 74
Replacing GB/T 9251-1997
Methods for hydrostatic test of gas cylinders
ISSUED ON: DECEMBER 30, 2011
IMPLEMENTED ON: JUNE 01, 2012
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 Terms and definitions, symbols ... 4
4 Principle ... 6
5 Test devices ... 6
6 Test measuring instruments and appliances ... 8
7 Pressure proof test ... 9
8 Determination of cylinder volumetric expansion by water jacket hydrostatic test ... 10
9 Determination of volumetric expansion by hydrostatic pressure test ... 13 10 Calculating numerical rounding rules ... 15
11 Precautions in the test ... 15
Annex A (normative) Verification of water jacket hydrostatic test device ... 17 Annex B (informative) Average compressibility of water ... 20
Methods for hydrostatic test of gas cylinders
1 Scope
This Standard specifies the basic requirements for test methods and test devices for hydrostatic test of gas cylinders.
This Standard applies to the hydraulic test of steel seamless gas cylinders, welded gas cylinders, aluminum alloy seamless gas cylinders and wound gas cylinders.
This Standard does not apply to industrial non-refillable steel cylinders and gas cylinders filled with solid fillers.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 13005, Terminology of gas cylinders
JJG 14, Verification Regulation of Non-self-indicating Weighing Instruments 3 Terms and definitions, symbols
3.1 Terms and definitions
For the purposes of this document, the terms and definitions defined in GB/T 13005 as well as the followings apply.
3.1.1 fiber-wrapped cylinder
On the outer layer of the metal (or plastic) inner liner, a composite gas cylinder is made by continuously winding multiple layers of resin-impregnated high- strength fibers (carbon fiber, glass fiber, aramid fiber).
3.1.2 high-pressure cylinder
A refillable seamless gas cylinder that contains compressed gas, high-pressure liquid gas, with a pressure ≥8MPa.
3.1.3 testing cylinder
The gas cylinder to be tested or being tested.
3.1.4 highest work pressure
The maximum allowable pressure of the gas cylinder.
3.1.5 pressure proof test
Apply a hydraulic test pressure greater than the maximum working pressure of the gas cylinder to test and verify the safety bearing capacity of the gas cylinder. 3.1.6 total volumetric expansion
The volume deformation of a cylinder under the pressure of a hydraulic test, including volume elastic deformation and volume residual deformation after pressure relief.
3.1.7 permanent volumetric expansion
After the pressure of the water pressure test is removed, the volume of the cylinder does not return to its original state and the remaining volume increases and deforms.
3.1.8 water jacket hydrostatic test
Put the testing cylinder into a special water jacket for pressurization. Determine the volumetric residual deformation or/and volumetric elastic deformation of the cylinder under test according to the amount of water overflowing from the water jacket and the remaining overflow after pressure relief of the gas cylinder under the hydraulic pressure test.
3.1.9 hydrostatic pressure test
Pressurize the cylinder directly with water. According to the water inflow of the testing cylinder under the hydraulic test pressure and the return water after depressurization, determine the volumetric residual deformation or/and
volumetric elastic deformation of the cylinder.
3.1.10 special water jacket
A special device used to determine the volume deformation of the testing cylinder during the hydraulic test.
3.1.11 calibrated cylinder
A special gas cylinder used to calibrate and verify the accuracy of the cylinder water pressure test device.
5.2 Pressure pipe
5.2.1 All pressure-bearing pipes of the test device shall be metal pipes. 5.2.2 Pressure-bearing pipes shall undergo a pressure proof test. The test pressure shall not be less than 1.5 times the pressure of the cylinder hydraulic test.
5.2.3 The pressure-bearing pipeline of the test device shall be fixedly installed and properly arranged. Ensure that all gases in the test system can be
exhausted.
5.2.4 The connection between the pipeline and the test device and the
measuring instrument shall have a good seal.
5.3 Special water jacket
5.3.1 The special water jacket in the water jacket hydrostatic test device shall be made of metal. It shall have a certain degree of rigidity to ensure that it does not produce volumetric expansion during the hydraulic test.
5.3.2 The special water jacket and its closure cover shall be designed to prevent leakage and gas storage.
5.3.3 A safety relief port should be provided at the bottom of the water jacket, so that the high-pressure water released when the gas cylinder bursts suddenly can be discharged smoothly.
5.4 Calibrated cylinder
5.4.1 The calibrated cylinder used for the water jacket hydrostatic test device of the calibration gas cylinder shall be manufactured by an organization with a gas cylinder manufacturing license and be calibrated by a qualified organization. 5.4.2 The calibrated cylinder shall be accurately calibrated for its total volumetric expansion value under no less than three test pressures. And it is clearly engraved on the shoulder of the cylinder.
5.5 Test water
5.5.1 The test water shall be clean fresh water. When the testing cylinder is a chromium-containing alloy steel gas cylinder, the chloride ion content in the test water shall not exceed 25mg/L. When it is the testing cylinder filled with oxygen or other strong oxidizing medium, the test water injected or pressed into the cylinder must not be contaminated by grease.
5.5.2 The temperature of the test water shall not be lower than 5°C. The difference between it and the ambient temperature shall not be greater than 5°C. The change of the water temperature in the testing cylinder before and after the water jacket hydrostatic test and the difference between the water temperature inside and outside the testing cylinder shall not be greater than 2°C.
5.5.3 A water tank containing test water shall be set up in the room with test device. The amount of water in the sink shall be compatible with the amount of gas cylinders to be inspected daily. After the water tank is filled with new water, it shall be left open for 8h before it can be used for hydrostatic test. 6 Test measuring instruments and appliances
6.1 Pressure measuring instrument
6.1.1 At least one pressure measuring instrument or pressure sensor that can display the test pressure correctly at the same time shall be installed at least at two points on the test device. And it shall be equipped with a precision pressure measuring instrument for calibration.
6.1.2 The range of the pressure measuring instrument shall be 2 to 3 times the test pressure of the testing cylinder. The accuracy level shall not be lower than 1.6. The range of the pressure sensor shall not exceed 2 times the test pressure of the testing cylinder. The relative error shall not be greater than 0.25%. The range of the precision pressure measuring instrument shall not exceed 2 times the test pressure of the testing cylinder. The accuracy level shall not be lower than level 0.25.
6.1.3 The pressure measuring instruments shall be checked regularly. The verification cycle shall be implemented in accordance with relevant regulations. 6.2 Water quantity measuring instrument
6.2.1 The water volume measuring instrument for measuring the volumetric expansion of the testing cylinder can be a measuring tube, an electronic scale or other suitable measuring instruments.
6.2.2 For the measuring tube used in water jacket hydrostatic test device, the relative error of the scale value on the measuring range for measuring the total volumetric expansion value of the testing cylinder or the measuring tube used in the hydrostatic pressure test device, the relative error of the scale value on the measuring range of the total water volume of the testing cylinder shall not be greater than ±1%. The minimum scale value shall be compatible with this error requirement. The relative error of the scale value of the measuring tube on the measuring range of the residual deformation value of the testing cylinder volume shall not be greater than ±1%. The minimum scale value shall not be greater than 0.1mL.
include at least the following content:
a) Test date;
b) Actual volume of the testing cylinder before the test;
c) Measured test temperature;
d) Actual test pressure;
e) Actual pressure holding time;
f) Total amount of water injected into the testing cylinder under the test pressure;
g) Amount of water pressed into the pressure pipe under the test pressure of the testing cylinder;
h) Total volumetric expansion value;
i) Permanent volumetric expansion value;
j) Permanent volumetric expansion rate;
k) What kind of cylinder body abnormality has occurred;
l) Tester’s signature.
10 Calculating numerical rounding rules
The calculation results of formula (1), formula (2), formula (3) and formula (A.1) in Annex A of this Standard shall be rounded off according to the following rules. Round to one decimal place according to the rules of rounding. But when the second decimal place is "5" and the following digit is "0", if the decimal to the left of "5" is an odd number, then enter "1". If it is an even number, it is discarded. 11 Precautions in the test
11.1 When installing the pressure measuring instrument, pay attention to draining the air in the pressure measuring instrument and its connecting pipe. 11.2 The anti-vibration ring shall be removed before the hydraulic test. Loosen the clamp used to clamp the gas cylinder.
11.3 In the process of boosting, if the boosting speed is found to increase or cylinder under the calibration pressure (given by the total volumetric expansion of the volume attached to the calibration bottle-pressure comparison table), in milliliters (mL).
The calculated results shall be rounded off in accordance with the provisions of Chapter 10. Keep one decimal place.
A.6 The verification results shall be recorded in the test record table of the testing cylinder in sequence. For each calibration of the test device, the results will occupy a row in the record table. The record of the verification result shall record the following contents:
a) Pressure gauge number and verification validity period;
b) Calibration date;
c) Calibration temperature;
d) Verification pressure;
e) Total volumetric expansion value;
f) Permanent volumetric expansion value;
g) Relative deviation of total volumetric expansion;
h) Signature of verifier.
A.7 The test device that meets the following requirements at the same time can be used for the water pressure test of the testing cylinder:
a) The relative deviation of the total volumetric expansion under the two verification pressures is not more than ±1%;
b) The permanent volumetric expansion value of the measured volume of
the calibrated cylinder under the calibration pressure is zero.
A.8 The precautions for using the calibrated cylinder to verify the test device are as follows:
a) Take care to prevent freezing after the calibrated cylinder is filled with water;
b) When the calibrated cylinder is filled with water, care shall be taken to prevent corrosion;
c) When the calibrated cylinder is not used for a long time, the test water shall be poured out and the inner cavity shall be dried before storage;
View full details