Micarta sheet in cryogenic applications
The high performing Micarta sheet can be used for both insulation and structural support in cryogenic environments that range from room temperature down to neat absolute zero (-273oC). Cryogenic technology is now widely used in many industries because freeze drying has become a rather common procedure in the preservation of food stuff. In the steel industry, special metal alloys are produced with the help of liquid nitrogen. Many applications in the chemical industry have become possible only through the use of cryogenic media. However, the storage and transportation of cryogenic media is only possible through high performance insulation material. It is very critical to ensure that the insulation system will not be damaged in cryogenic applications because the consequences would be great. Production costs can increase dramatically and process control can be compromised as well as its quality.
Important factors that determine a high performing cryogenic insulation
There are high demands from the insulation material that will be used in cryogenic applications. The most important selection factors that are considered include low evaporation losses, lowest possible energy losses during re-liquefaction and safe storage of the refrigerants. It is also important to ensure that condensation is prevented and the risks of corrosion minimized on the insulation. The insulation must also be able to absorb the impact of vibrations and impact that may result from extreme temperature cycles. It should also be able to withstand external mechanical strain. Aside from the materials that were used in the insulation, the technical construction of the insulation material is also important.
Many insulation materials tend to harden when the temperature is below 50oC or what is referred to as the glass transition period. Mechanical behavior also changes and flexibility is often lost. However, hardening of the insulation material is completely reversible and when the temperature rises, the insulation material regains its flexibility but lack of strength at cryogenic temperatures must be considered very carefully particularly in its overall construction. Cost is another major factor in the choice and it should justify the performance level.
A number of insulation materials are now available for cryogenic insulation which includes the Micarta sheet. When heat and pressure is applied to layers of paper or glass cloth that have been impregnated with synthetic resin, the result is a phenolic sheet with excellent dielectric strength, good machinability, light weight, heat and wear resistance, corrosion and chemical resistance and good mechanical strength and dimensional stability. For cryogenic storage facilities, phenolic sheets can prevent heat transfer that would adversely affect the storage.