Linde Group is a leading global company of industrial gases and engineering with approximately 50,500 employees in over 100 countries. As one of the first international industrial gases companies to enter China since the 1980s, Linde has closely cooperated and grown with its customers in the chemical, petro-chemical, metallurgy, manufacturing, electronic, food, and pharmaceutical industries. Atlas Copco and Linde Industrial Gases Group have cooperated on a global scale with hundreds of high pressure compressors providing power for Linde gas supply facilities.
In 2011, Linde purchased two sets of helium compressors for its helium provision facilities in Pixian, Chengdu. The project was to supply cooling helium for an international manufacturer of professional medical imaging technology products, primarily magnetic resonance imaging (MRI) systems. MRI systems require a continuous supply of low-temperature air to cool the magnetic coil of the scanner. This creates superconducting properties in the coil and ensures the current smoothly flows through it, generating a high-intensity magnetic field.
High volume rate, low maintenance costs and safe operation
Liquid helium is the only cooling media that can cool the magnetic coil to an ultra-low temperature to achieve superconductivity (zero resistance). However, the liquid helium pressure generated in the high-pressure container can be up to 50-60 Psig and cannot be pumped directly into the MRI device. Instead a professional helium compressor pumps out and decompresses the liquid helium to 10 Psig or below so it can then be used to fill the MRI device.
A helium compressor is also required to exhaust the evaporated helium that is generated when producing an MRI. This can greatly affect compressor performance and stability. Therefore, Linde chose a helium compressor from Atlas Copco.
Atlas Copco’s helium compressor is specifically designed for low-density gases. The level-5 compressor features a low compression temperature and a gas-tight crankcase design to ensure that there is no gas loss or gas pollution when sending return air from the crankcase to the suction side. It features a high volume rate, low maintenance costs and safe operation, and it has been widely recognized throughout the world.
Stable operation since 2012
“We selected Atlas Copco compressors not only because Atlas Copco is a leader in today's high-pressure systems, but also because of their excellent performance, high reliability and durability. We had even greater confidence after Linde and Atlas Copco established long-term, worldwide cooperation,” said Mr. Yang Jun, Site Director of Chengdu Branch of Linde Gases, who is responsible for the project.
“Helium has the characteristic of very low, compression-specific heat, so the temperature of the helium can be increased to very high when compressing it. It also requires that air mixing be absolutely eliminated. Meanwhile, the MRI device requires no compressor downtime due to very long pre-cooling times or high operating costs. This requires a high-performing compressor. Helium compressors are designed to specifically meet the needs of helium conveying, including high operating stability and safety. This is the reliable guarantee of the whole liquid helium supply project!" Mr. Jun added.
Two sets of helium compressors are used for high purity and low purity helium conveyance. Since on-site testing in March 2012, the units have been in stable operation. As the After-sales Service Manager of Atlas Copco Western, Mr. Zhang Daipin observed the trial run at Linde’s Pixian location. He said, “Atlas Copco’s professional team adheres to a customer-centric service concept to safeguard that the product can stably and efficiently function with regular on-site services.”