Criogenic perlite

Perlite insulation for cryogenic use or low temperatures perlite insulation displays low thermal conductivity through a wide range of densities; however, the recommended density is from 48 to 72 Kg./m3/ (3 to 4 lb./ft3)
In addition to its excellent thermal properties, perlite insulation is relatively low in cost and its installation and handling is very easy. Due to its structure, cryogenic perlite insulations de not deform the container to be insulated.
Since it is non-combustible, it complies with fire regulations, thus diminishing insurance rates.
For being an inorganic material, it is decomposition and mosstested, and as a result of its closed cellular structure, the material does not retain humidity.

There are different concepts of low temperature, cryogenic storage receptacles.
However, most of them are two-wall constructed with the surrounding crown filled with expanded perlite.
Perlite in bulk may be used to insulate the smallest receptacles by pouring or blowing the insulation on the job site. Portable plants for perlite expansion are usually used to insulate storage receptacles, cold boxes, ships, and other two-wall receptacles and tubes. For these applications, perlite mineral is expanded on the job site and expanded perlite insulation is pneumatically introduced into the ring. In the event of large works, Perfiltra S.A. has portable plants for expansion.

Perlite insulation for cryogenic services displays low thermal conductivity through a wide range of temperatures, pressures, and densities. The standard density varies from 128 to 152 Kg/m3 (8 to 9 lb/ft3). The chart above gives information on thermal conductivity for expanded perlite with a density of 139 Kg./m3 (8.7 lb/ft3) at average temperatures ranging from -18º C to -107º C (0º F to -160º F).
Perlite thermal conductivity, which is installed with an interstitial vacuum of 10 microns, is up to 22 times lower than perlite used in a traditional container insulated by atmospheric pressure.

Perlite insulation
Expanded perlite may be fabricated in densities that range from 32 Kg./m3 (2 lb. /ft3) to 240 Kg./m3 (15 lb. /ft3), making it capable and versatile for use in insulations.
Due to its unique properties, perlite insulation has been fully accepted by cryogenic, low temperature storage tanks insulation in shipping containers, cold boxes, trial chambers, and food processing.
Temperatures of -100º C (-150º F) and lower are considered cryogenic and upward, up to 4º C (40º F), are considered to be of low temperature. Supercold or extremely cold fluids, such as hydrogen and helium, are usually stored in two-wall receptacles which ring spaces contain perlite, and are submitted to a high vacuum degree. Apart from being used for insulation in big seasonal tanks, vacuum perlite is used to insulate smaller containers fabricated at workshops, designed to store many cryogenic gases, such is the case of central systems in hospitals.

Perfiltra S.A, provides installation services .
Some of its major projects include: Air Liquide; AGA; C.B.I.; Criogen; Indura; Messer; Praxair; P.D.M. and many others.