The oxygen cylinder hydrostatic test is essential to ensure oxygen cylinder safety during daily use. Oxygen cylinders can be categorized into aviation oxygen cylinders, medical oxygen cylinders and industrial oxygen cylinders, all of which are seamless gas cylinders. How do you determine whether an oxygen cylinder that has been used for a long time can be refilled with oxygen? You need to use the water jacket method oxygen cylinder hydrostatic test to determine whether an oxygen cylinder is qualified.
Water Jacket Method Oxygen Cylinder Hydrostatic Test
The oxygen cylinder hydro test uses the water jacket method to perform oxygen cylinder volume expansion deformation test. It will precisely detect the volumetric expansion rate of an oxygen cylinder, thereby determining whether the oxygen cylinder is qualified and suitable to serve. Therefore, This testing method is also known as the oxygen cylinder water jacket test.
Oxygen Cylinder Hydrostatic Test Procedures
The oxygen cylinder hydro test machine is an indispensable testing equipment for oxygen cylinder hydro testing. First of all, fill your oxygen cylinder with clean water, then place it in the water jacket where is also full of clean water, and seal the water jacket with a lid. Then use the hydro test machine to pressurize the oxygen cylinder in two stages. To be specific, pressurize oxygen cylinder to its working pressure, then pressurize the cylinder to 1.5 times its working pressure, and then maintain the pressure. During the pressure maintaining period, the oxygen cylinder expands due to internal high pressure, which forces some water to flow from the water jacket into a measuring cup. After pressure relief, the oxygen cylinder restores partially, so some water in the measuring cup flows back into the water jacket. The amount of water remaining in the measuring cup is the residual volume deformation of the oxygen cylinder. The hydro test machine will automatically calculate the oxygen cylinder’s deformation rate to determine its qualification. Normally, if an oxygen cylinder’s deformation rate exceeds 10%, the oxygen cylinder is unqualified and can’t refill oxygen gas.
Precautions for Oxygen Cylinder Hydro Test
Oxygen cylinders are classified as oil-free gas cylinders, namely oil-restricted gas cylinders. Therefore, it is crucial to ensure that the test medium, pipelines and hydro test equipment are free of grease during testing process. Ordinary gas cylinder hydro test machines are designed for ordinary gas cylinders and are not suitable for oxygen cylinders. To address this, Senwell developed a gas cylinder hydrostatic test machine with dual test stations. One test station is suitable for common gas cylinders, while the other test station is specifically designed for oxygen cylinders and other oil-free gas cylinders. The piping, pressure gauges, valves and high-pressure pump at this test station are all degreased to prevent grease from entering the oxygen cylinder during testing. In addition, the machine can be optionally equipped with a stainless steel water jacket, whose inner wall will not produce metal debris and rust stains, which may scratch or contaminate oxygen cylinders.
Frequently Asked Questions
Why pressurize oxygen cylinder in two stages during oxygen cylinder test?
During oxygen cylinder hydro testing, you need to pressurize oxygen cylinder in two stages. Firstly, pressurize the cylinder to its working pressure, then pressurize the oxygen cylinder to 1.5 times its working pressure. The purpose of this is to avoid pressurizing too quickly, which could lead to localized stress concentration inside the oxygen cylinder, and prevent the detection of potential defects, thereby affecting the accuracy of the test results.
What is the oxygen cylinder hydrostatic test interval?
Oxygen cylinder hydro test interval is 1 year, but regulations may differ between countries.
