Adaptive Compressor design for customer-specific needs

Recirculation and compression of noble gases is a delicate task due to gas properties and cleanliness requirements. Learn more about the benefits of our gas bearing turbo compressors.

Noble gases have the characteristic tendency not to react with other chemical substances. This makes the gases predestined for controlling and protecting critical physical and chemical processes. Application examples are:

• Providing a non-reactive atmosphere in manufacturing processes like welding, additive manufacturing or heat treatment
• Carrier gas in industrial chemical plants
• Flushing of semiconductor applications
• Generating standardized quality control environment
• Cooling of sensitive equipment like sensors and lasers and physical experiments down to cryogenic temperatures

These gas properties make it difficult to compress noble gases. The speed of sound in Helium is about three times higher than in Air, posing a challenge when compressing the gas and therefore also in terms of the aerodynamic design. As an example, if the same aerodynamic design is applied to Helium and to Air, very different compressor maps are the result, as depicted below.

Similarly, the viscosity of the processed gas is the key parameter to consider for the gas bearing design. These properties depend not only on the gas, but also on the temperature and pressure conditions. This means our engineers have to account for all possible operating conditions to ensure the compressor can fulfill the customer requirements.

Typically, no contamination is allowed in applications employing noble gases. Therefore, cleanliness and oil-free compression are essential. Finally, the applications usually have critical requirements concerning other aspects such as leak-tightness, high absolute pressure capability, allowed process gas, wetted materials, and/or energy consumption.

Celeroton gas bearing turbo compressor technology can bring significant benefits to applications with such requirements:

• Leak-tight: We know how to achieve Helium leak-tight casings
• Maintenance-free for years; allowing for several 100,000 start/stop cycles
• Reliable and robust: Our gas bearings are self-stabilizing
• Contamination-free: Contactless gas bearings need no other lubricant than the process gas itself
• Silent: You will be amazed at how silent our compressors are

Most of these advantages can be achieved due to the gas bearing principle: A hermetic sealing of the process gas within the rotor compartment is possible without rotating seals. No lubrication is required as the process gas itself is the lubricant for the bearing, and no wear is present in operation as the rotor is floating on the process gas film.

To illustrate how the capability of the Celeroton gas-bearing turbo compressor technology is, two exemplary rare gas compressors are depicted in the following table and figures:

Both compressors are based on the same baseline compressor: The same rotor and motor parts are used. The gas bearing and aerodynamic design are customized and optimized to the specific pressure, temperature and gas requirements. Furthermore, the housing is optimized for minimal gas contact surface and low leakage requirements in one case and for high pressure capability in the other case, including the appropriate safety measures.

Customer requirements are verified on Celeroton in-house test bench, which includes gas bearing stability testing in the entire gas parameter range, closed-loop testing to verify the compressor map and efficiency performance, and safety aspects such as electrical isolation and high-pressure testing.

Each application has different requirements concerning pressure levels and mass flow, such that custom adaptations or a custom development are essential. If pressure levels and mass flow exceed the capability of single stage turbo compressors, series or parallel connections of turbo compressors can extend the range. Learn more about custom developments and contact us for your specifications via moc.notorelec@selas or +41 44 250 52 20.