GB 8337-2011Fusible plug device for gas cylinders (English PDF)

4.2 Fusible alloy flow temperature

Fusible alloy flow temperature should meet the requirements of the operation temperature of the fusible plug means, the flow temperature range and deviation should satisfy 4.3 Fusible plug means a predetermined operation temperature.

4.3 Fusible plug means operating temperature

Operating temperature fusible plug device is divided into three. 70 °C 4-2 °C (nominal operating temperature was 70 °C, except for the well-dissolved acetylene cylinders He said working pressure is less than or equal to the cylinder 3.45MPa); 100 °C ± 5 °C (nominal operating temperature of 100 °C, for acetylene cylinders);

102.5 °C ± 5 °C (nominal operating temperature was 102.5 °C, for the nominal working pressure of 30MPa and not more than 3.45MPa greater than Cylinders).

5.1 Plug material

5.1.1 plug material should have sufficient mechanical properties and corrosion resistance, and should be compatible with the media bottle.

5.1.2 plug material copper alloy, steel or other suitable metal should be used. Plug for dissolved acetylene cylinders, non-selected amount of copper 70% of the copper alloy, and silver, zinc, cadmium and its alloys.

5.1.3 chemical composition and mechanical properties of the plug material should conform to appropriate technical standards, to meet the requirements of manufacture and use, and should be effective the quality certificate, or should retest.

5.2 Plug basic types

5.2.1 plug type can be substantially Referring to FIG 2, other types may also be employed. However, any type of plug, which shall be constructed to have sufficient Strength and stiffness, can not be deformed in use.

5.2.2 In vitro threaded plug should PZ27.8 PZ19.2 or conical external threads, or GB specified in GB 8335-2011/T 7306.2-2000 specified in R21/R21 or 4 /. 8 conical external threads.

a) Cone b) stepped hole c) a threaded bore 2 a schematic view of the basic version of the plug body Easy 6-fluxing

6.1 Configuration fusible alloy materials shall comply with relevant technical standards, and should have a valid certificate of quality, or should retest.

6.2 fusible alloy should be bismuth, lead, tin, cadmium gravimetrically composition suitable eutectic alloy containing bismuth content of not less than 48%, the formula See Appendix A.

6.3 fusible gold purity of raw materials.

Bismuth. 1 satisfies a predetermined table, the chemical analysis methods and bismuth impurities accordance YS/T 536;

Lead. not less than the minimum requirement GB/T 469 as specified;

Tin. not less than 728 minimum requirements specified in GB/T ;

Cd. not less than the minimum specified in claim 72 YS/T.

Table 1

Trademark

chemical composition/% not less than Impurity content of not greater than Ag Cu Pb Zn Fe arsenic, antimony chloride, tin telluride, Cd, Hg Ni Bi99.95 99.95 0.003 0.010 0.005 0.001 0.020 0.001 0.001 0.002 0.005 - - - -Note. The content of bismuth is 100% minus the sum of the impurities measured.

6.4 Fusible preparation of gold

6.4.1 fusible alloy formulation is determined, the weighing scale formulations, press bismuth, lead, tin, cadmium order sequentially melted liquid.

6.4.2 bismuth and lead in the mixing process, the temperature should not exceed 371 deg.] C; when adding tin and cadmium, the temperature should not exceed 260 °C.

6.4.3 Each fusible alloy casting furnace should be carried out continuously in the same class. Casting the casting temperature should be higher than the flow temperature of the fusible alloy, and Before each casting, first floating on the liquid surface of the slag, dirt, metal oxides and other impurities removed.

6.4.4 After melting the raw material, should be cast into rods or ingots fusible alloy, good casting each of the fusible alloy ingot or rod should have a permanent, significant Heat number marked.

8.2 Fusible alloy flow temperature test

8.2.1 From each furnace fusible alloy optionally two test specimens, having a diameter of 6mm, a length of 50mm.

8.2.2 The sample was horizontally supported at a distance of 25mm on the edge, the projecting ends 12.5mm outer edge, and then immersed in glycerol Slot, which is controlled by the temperature of the outer groove glycerol, the test apparatus shown in Figure 3.

In millimeters

Description.

1 --- fusible alloy specimen;

2 --- glycerol inner groove;

3 --- glycerol outer groove;

4 --- heater.

FIG 3 is easy to test a schematic flow temperature fusing gold

8.2.3 two samples should be tested simultaneously, the temperature of the glycerin bath insert with a thermometer or thermometer, is placed between two samples, the temperature Meter bulb thermometer or maintain the same level of the sample, glycerin bath temperature rise rate is not more than 2 °C/min, until the temperature of the glycerin bath was raised to Fusible alloy is the lowest temperature flow 6 °C.

After the temperature of the glycerin bath is to be stable at this temperature, the temperature of the glycerin bath is not more than 0.6 °C/min rate of temperature raising was continued until the fusible Alloy blown. Glycerol may be agitated during the test such that the temperature uniformity.

8.2.4 Acceptance rules

Two samples of four fulcrum fusing temperature at the second end portion of the fuse, i.e. flow temperature fusible metal, the fusible alloy flow Temperature variation range and shall meet the requirements of 4.3.

8.3 Test apparatus fusible plug

General provisions 8.3.1 Batch and testing 8.3.1.1 fusible plug means to be not more than 3,000 as a number.

8.3.1.2 optionally two samples from each batch of fusible plug device, 8.3.2 and 8.3.3 predetermined successively tested, the test thermometer Thermometer or fusible plug means as close as possible, the test device shown in Figure 4.

Description.

1 --- fusible plug samples;

2 --- thermometer;

3 --- communication hole temperature;

4 --- heater;

5 --- Glycerol groove;

6 --- pressure channel;

7 --- air tank;

8 --- pressure gauge.

4 a schematic diagram of the test apparatus of FIG fusible plug

8.3.2 Fusible plug means resistance against extrusion test

8.3.2.1 nominal working pressure for less than or equal to the anti-fusible plug means on the extruded cylinder 3.45MPa test. the sample within the cylinder One end portion of the compressed air is applied to the medium in contact with a test pressure of 3.45 MPa, and kept at 60 deg.] C of not less than 24h, and then the other end of the inspection, no leakage no visible extrusion workability fluxing qualified.

8.3.2.2 nominal working pressure for not more than 3.45MPa greater than the fusible plug means 30MPa cylinder on the anti-extrusion test. Test One end of the sample medium in contact with the compressed air inside the cylinder is applied, the test pressure is not less than 70% of the test pressure of the hydraulic cylinder, and not low Conditions for 24h at 82 deg.] C, and then checks at the other end, no leakage no visible extrusion workability fluxing qualified.

8.3.2.3 Regulation for each nominal working pressure is greater than 3.45MPa fusible plug means and not greater than 30MPa over the cylinders, the new design Grid fusible plug means, before the product should be arbitrarily selected three representative samples, the following tests under conditions of not lower than 82 deg.] C.

Sample should be between 2.1MPa and 70% of the cylinder hydrostatic test pressure does not exceed four times/min, the rate of fatigue tests, 26,000 times the sample should be no leakage fluxing no visible extrusion workability.

The sample was then held at 70% 500h cylinder hydrostatic test pressure, no leakage after the test with no visible extrusion workability fluxing qualified.

8.3.3 Fusible plug means operating temperature test

8.3.2 Qualified will predetermined test two samples screwed on the abutment end in contact with the medium inside the cylinder downward, and through the end Compressed air, which pressure is not less than 0.02MPa. At the same time, the sample was immersed in a glycerine bath, the temperature of the glycerin bath should be a predetermined maximum Low temperature operation within 3 °C, for at least 10min at this pressure and temperature, should be no leakage.

Glycerin bath temperature was then raised, the rate of temperature increase of not more than 0.6 °C/min. In the meantime, the pressure can be increased to not more than 0.35MPa. When the sample fusible alloy extruded air leakage, note the operation temperature of the glycerin bath temperature at this time as a fusible plug means degree. Fusible alloy extruded should occur within 10min after the maximum allowable operating temperature has been reached and stabilized the test, the temperature deviation and Range should meet the requirements of 4.3.

8.3.4 Acceptance rules

Two samples shall meet the requirements of 8.3.2 and 8.3.3, the batch is qualified. If there is a failure in two samples should be from the same Optionally further batch four samples tested, four samples as long as there is a requirements are not met, the batch scrapped.

8.4 Fusible plug tightness testing device

Fusible plug means to be individually tested for leakage, the test medium using air, said test pressure is a pressure corresponding to the working cylinders known 1.25, dwell time should not be less than the dwell time of the respective cylinders airtightness test, no leakage is acceptable.

9.3 Flag sequence

Flag should be arranged along a circumferential line, each of the items by 9.2 in a), b), c), d) arranged clockwise.