GB/T 34530.1-2017Valve for cryogenic insulated cylinder - Part 1: Pressure regulating valve (English PDF)

3.1 Pressure build regulator

A valve that vaporizes the liquid in the pressure build line of cylinder, to raise and stabilize the cylinder's pressure.

3.2 Pressure economizer regulator

A valve that makes the cylinder to preferentially use the gas at the top of the liner and maintains stable working pressure of the liner.

3.3 Combination pressure regulator

A valve that has both the pressure-increase function and the pressure- reduction function.

3.4 Pressure build inlet

The inlet of the pressure build regulator and the combination pressure regulator, which is connected to the pressure build line of the cylinder.

Note: The pressure build inlet is identified by PB IN.

3.5 Pressure build outlet

The outlet of the pressure build regulator, which is connected to the gas phase space of the cylinder.

Note: pressure build outlet is identified as PB OUT.

3.6 Pressure economizer inlet

5.1.2 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.

5.1.3 Non-metallic sealing materials

5.1.3.1 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.

5.1.3.2 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%.

5.2 Design and process requirements

5.2.1

Valves and cylinders shall be thread-connected. The thread's size should be NPT 1/4. The thread's precision shall meet the requirements of GB/T 12716.

5.2.2

The valve shall, according to the working pressure of the cylinder, be pre- adjusted to a set pressure value. It shall also mark the set pressure value and pressure regulating range on the valve.

5.2.3

The joints of the valve shall be permanently marked by abbreviated markings.

5.2.4

The valve shall be so designed that the rotation of regulating screw clockwise will increase the set pressure, otherwise it will reduce the set pressure. Meanwhile it shall have a locking device.

5.2.5

It shall, according to the thermal expansion coefficient of the material, set the clearance of the moving parts, to ensure that the moving parts are able to move flexibly within the design temperature range.

5.2.6

The upper part of the bonnet shall have a venting hole, to keep the pressure in the upper cavity consistent with the outside.

5.2.7

The sealing structure of the pressure build regulating should use metal- […]

5.3.4

Pressure regulating performance of combination pressure regulator

and pressure build regulator

The valve shall, within the pressure regulating range, be pre-adjusted to a set pressure. The allowable difference between the actual closing pressure of the valve and the set pressure shall not exceed 5%. When the pressure at the pressure build outlet is 90% below the set pressure, the valve shall open.

5.3.5 Pressure-regulating performance of pressure economizer regulator

The valve shall, within the pressure regulating range, be pre-adjusted to a set pressure. Under the set pressure, the valve shall act. Reduce the pressure at the input end of the valve. When the flowrate drops to 50 mL/min, the pressure at the input end at this time must not be lower than 95% of the set pressure.

5.3.6 Opening performance of pressure economizer regulator

At 102% ~ 105% of the set pressure, the valve's output flowrate shall be not less than 800 mL/min.

5.3.7 Vibration-resistance

Under the nominal working pressure, the valve shall be able to withstand a vibration which has a displacement amplitude of 2 mm (P-P), a frequency of

33.3 Hz, a time of 120 min, in three mutually-perpendicular directions (X, Y, Z).

Each threaded connection on the valve shall not loose. Meanwhile it shall meet the requirements of 5.3.2.1.

5.3.8 Durability

Under the action of the liquid nitrogen gas at 105% of the set pressure, the valve is subjected to 30000 pressure cycles as follows:

a) 28000 cycles at room temperature;

b) 1000 cycles at a temperature of 85 °C ± 2 °C;

c) 1000 cycles at -40 °C ± 2 °C.

The change of set pressure of the valve shall not vary by more than 5%.

Meanwhile it shall comply with the requirements of 5.3.2.1.

5.3.9 Resistance to salt spray corrosion

The valve shall, within the salt spray chamber of 33 °C ~ 36 °C, according to the test method of 6.14, be subjected to 96 h of salt spray test. The change of […]

6.3.2 Test of mass change

This test uses the same group of specimens as for the test of volume change.

After finishing the test of volume change, place the sample in air at 40 °C ± 3 °C for at least 48 h. Then place it at room temperature until the mass is constant.

Record the final weighing value (M 2 '). The mass change rate is calculated according to the formula (2):

Take the average of the three samples as the test results, which shall meet the requirements of 5.1.3.2.

6.4 Visual inspection

The appearance of the valve shall be checked by visual inspection. The results shall comply with the provisions of 5.2.10 and 8.1.

6.5 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.

6.6 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

5.3.1.

6.7 Test of airtightness

6.7.1 Test of airtightness at ambient temperature

At ambient temperature, block the PB IN and PB OUT of valve. From the PB IN (combination pressure regulator, pressure build regulator) and PB OUT (pressure economizer regulator), fill in the dry, clean nitrogen or air, to 1.2 times the nominal working pressure. Immerse it in water to hold pressure for at least

1 min. It shall meet the requirements of 5.3.2.1.

6.7.2 Test of airtightness at low-temperature

6.7.2.1

Test of airtightness of combination pressure regulator and

Mass change rate […]

6.14 Test of resistance to salt spray corrosion

Place the valve in a salt spray chamber at 33 °C ~ 36 °C. Block each 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 6.7.1, 6.9, 6.10, carry out corresponding test. The results shall comply with the provisions of 5.3.9.

6.15 Test of resistance to stress corrosion

Remove the grease from the valve. Use a torque of 30 N · m to tighten the plugs on each port 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 5.3.10.

Note: 30 N · m is the tightening torque of NPT 1/4 thread. If using other threads, it shall, according to the sealing requirements of the interface, determine the corresponding torque.

7.1 Inspection of raw materials

7.1.1

The enter-factory materials and parts shall have a quality certificate.

7.1.2

The valve material shall, based on batches of materials, be subjected to enter-factory re-inspection of mechanical properties and chemical composition.

7.2 Exit-factory inspection

7.2.1 One-by-one inspection

The valve shall be inspected one by one before exit-factory. The inspection items shall be as specified in Table 1. In the course of inspection, if one item fails, the valve is unqualified.

7.2.2 Batch inspection

The valve shall be taken from the products that are continuously produced and qualified after one-by-one inspection from each batch (not more than 2000 products form one batch). Take 3 samples from each batch. Where the number of finished products per batch is less than 2000, also take 3 samples. The […]

8.1 Marking

The valve shall have a clearly-visible, easy-to-view permanent marking, which shall include at least the following:

a) The model of valve;

b) The pressure regulating direction of the valve;

c) The pressure regulating range and set pressure of valve;

d) The port identification of valve;

e) The name or trademark of the manufacturer;

f) The production batch number, product serial number;

g) No. of special equipment manufacturing license and the marking of .

8.2 Packaging, transportation, storage

Packaging, transportation, storage shall be in accordance with GB/T 15382.

9 Product certificate, quality certificate of product batch inspection

9.1 Product certificate

Each valve shall be accompanied by a product certificate (or electronic certificate mark). The certificate shall include the following contents:

a) The certificate number;

b) The name and model of the valve;

c) The pressure regulating range and set pressure of the valve;