Super Insulation
CSM use specially made radiation shield that posses extremely low emissivity coefficient commonly indicated with the symbol ε. The radiation shield is manufactured with just few micrometers thickness and therefore reduce total radiation heat absorption Qr into the cryogenic system. While the radiation shield is effective in reflecting some of radiation heat, it also adsorbs and transmits the some of the heat to next adjacent layer by solid conduction. To minimize radial heat transfer between adjacent layers of radiation shield, a spacer is placed between them. The spacer is made from proprietary inorganic glass fiber material which is flame retardant and compatible for liquid oxygen service certifed to US DOT MC-338. This spacer is manufactured with a specific porosity allowing interstitial vacuum space to form an efficient thermal barrier. All super insulation materials used in our manufacturing will undergo degassing treatment using extreme heat and high vacuum process in combination with cryogenic condensation procedure to remove volatile hydrocarbon and lighter gas molecule species.
The twin-layer super insulation material is then carefully applied to the process pipe using semi-automatic wrapping machine forming mulitple layers insulation. The wrapping load is controlled ensuring consistent bulk density of 25 layers/cm throughout the entire pipe length. More than 40 layers of the radiation shield are applied to achive desired radiation heat barrier according to our calculation model. This is then followed by high temperature baking and UHV evacuation process to remove moisture & gas molecules residues from the annular space. The final outcome is a product with extremely low apparent thermal conductivity Kt that is virtually free of heat leaks that cause the expensive boil-off to your cryogen.
Key Benefits of multilayers super insulation:
- Lesser cryogen boil-off
- Elimimating two phase flow in pipeline
- Stable cryogen pressure & temperature to your equipment
- Lesser cryogen boil off means faster payback to your investment
For liquid nitrogen system, we provide two types of vavuum insulation to suit your needs:
- Static Vacuum : vacuum annular space is evacuated and sealed at factory
- Dynamic Vacuum : continuous onsite evacuation with vacuum pump
Read more to understand the difference.....
Typical Structure of Super Insulation
The success of the super-insulation will depend on the following parameters:
- Outgassing rate of the materials use within the vacuum annular space, such as spacers and radiation shield material
- Absorption & adsorption rate of the getter and absorbent material use and its ability to perform long period scavenging of various type of gas molocule species form the vacuum annulus, in order to prolong the vacuum integrity
- Wrapping design and technique to avoid linear heat conduction by the radiation shield itself which will result in increase of heat leaks
- Bulk density of the radiation shield and spacer is very critical to ensure solid conduction is kept to the minimum. Increase in bulk density is know to increase solid heat conduction between layers of MLI
Close Tolerance Bayonet Connections
- Lowest heat leak in its class
- Extremely close tolerance design to minimize convective and conductive heat transfer
- Higher heat barrier factor, eliminate condensation or frosting at clamp joints
- Installation flexibility, suitable for any installation position, vertical or horizontal
- Bi-directional flow direction