GB/T 18443.1-2010Testing method of performance for vacuum insulation cryogenic equipment - Part 1: Basic requirements (English PDF)

4.1 Environmental conditions

4.1.1 The test environment shall be clean, well ventilated, and shall be provided with anti-static and fire-proof measures.

4.1.2 The test site shall be equipped with warning areas and red signal signs.

4.1.3 The test site shall not have strong electromagnetic interference, strong vibration and shock.

4.1.4 The ambient pressure shall be the local atmospheric pressure, where the temperature range is 0 °C ~ 40 °C, and the relative humidity is less than 85%.

4.1.5 When a flammable and explosive cryogenic liquid is used as the test medium, a safe area shall be set up, and no dangerous source that may cause danger shall exit.

4.2.1 Basic requirements

4.2.1.1 When the test medium is a flammable and explosive cryogenic liquid, the measured piece and the measuring pipeline shall be provided with necessary anti-static measures, and no open flame shall be generated.

4.2.1.2 The performance, range and accuracy of the instruments and equipment shall meet the test requirements. Measuring instruments and equipment shall be calibrated or verified to be qualified by the national legal measure institute, and shall be used within the validity period of the calibration.

4.2.1.3 After the vacuum insulated cryogenic equipment is filled with cryogenic liquid, in the preparation stage of standing still, an air pipe shall be used to guide the vaporized gas from the vent of the cryogenic container to a designated safe area. The air pipe and each connector shall be well sealed and shall not leak.

4.2.1.4 When the test medium is a flammable medium, use nitrogen or inert gas to replace the relevant connecting pipes first. The vents of the vacuum insulated cryogenic equipment and the exhaust pipes of the safety valve vents shall be connected to the prepared airbags, recycling devices, or safety vents by pipelines.

4.2.1.5 The allowable measurement error of the thermometer is ±1 °C.

4.2.1.6 The allowable measurement error of the atmospheric pressure gauge is ±

4.2.2 Vacuum unit

4.2.2.1 The final vacuum degree of the vacuum unit shall be at least one order of magnitude higher than the vacuum degree of the seal of the measured piece.

4.2.2.2 The effective pumping speed of the vacuum unit shall meet the gas load of the measured piece.

4.2.3 Vacuum gauge and vacuometer

4.2.3.1 The rubber seal connector of the vacuum gauge shall comply with the regulations of JB/T 8105.1; the metal seal connector of the vacuum gauge shall comply with the regulations of JB/T 8105.2.

4.2.3.2 The type and measurement range of the vacuum gauge and the supporting vacuometer shall meet the requirements for vacuum degree of the interspace in the tested vacuum insulated cryogenic equipment; the uncertainty of measurement of the vacuum degree shall be less than 50%.

4.2.3.3 Hot-cathode and cold-cathode ionization vacuum gauges are not allowed to be used in high-vacuum multi-layer insulated cryogenic equipment that is loaded with liquid oxygen or flammable medium.

4.2.3.4 The vacuum interspace of the high-vacuum multi-layer insulated cryogenic equipment - which is loaded with liquid oxygen or flammable medium - can be equipped with a composite gauge combining resistance gauge and ionization vacuum gauge, or be installed with a resistance gauge and an ionization vacuum gauge in parallel. The ionization vacuum gauge can be started for measurement only when the vacuum degree is greater than 10-

4.2.4 Vacuum valve

4.2.4.1 The diameter of the air extraction pipeline connected with the evacuation unit and the vacuum valve on the measured piece shall be larger than that of the vacuum valve on the measured piece.

4.2.4.2 The leak rate of the vacuum valve shall not exceed 1×10-

4.2.5 Connecting pipeline The material of the connecting pipeline should be stainless steel, copper or aluminum alloy.