This page is designed to inform the reader about the advantages and disadvantages of several different cryogenic piping supply system as well as gain a glimpse into the Engineering process.
This will be, by far, the most extensive part of the PRINCETON CryoTech INC website and is currently under construction. If you experience any errors please be patient while we continue to update this site.
Cryogenic supply systems have evolved over the past 150 years. During that time thermodynamic engineers have developed amazing new technologies that have greatly increased the efficiency of the cryogenic piping supply systems.
The first, and oldest type of supply system used simple copper or stainless steel pipe wrapped with wood insulation. Wood was later replaced by mica, then shortly after polyurethane foam. Foam insulation is highly inefficient and cumbersome; much of the liquid nitrogen traveling through the pipe turns to gas and pipe diameters are often over 8 inches. These large, bulky, inefficient piping systems were relatively cheap to install, but the loss of liquid nitrogen makes them to be very expensive in the long run.
Vacuums are one of the best ways to eliminate heat conduction, so finally a dynamic vacuum piping system was developed. This piping system uses a pipe inside a pipe. The outer jacket pipe is constructed of upper bellow tubing and surrounds the copper inner bellow tube with an airtight-as-possible seal that technology could afford. To maintain a thermo-arresting vacuum, the ultimate insulator, between the two layers a vacuum pump is attached to the line. The vacuum pump works continuously, 24/7. The dynamic vacuum piping system dramatically decreased heat loss, and therefore was a much more efficient system. While the dynamic system is much more effective than foam, materials and installation cost much more, and the time and maintenance required for the pumping system is highly cost ineffective due to electricity consumption.
The most recent and best engineerined cryogenic piping system available is the Static Vacuum Jacketed system. The Static system contains all the benefits of the Dynamic System without all the maintenance headaches and optional cost issues.. Pieces of vacuum jacketed pipe (VJ sections) are designed according to spec and are connected with very low enegy loss bayonet style fittings. This system is less complex to install than a Dynamic System and extremely efficient. While it generally is the most expensive system to install, it easily makes up the cost in performance, efficiency and long term duration; some well-engineered systems built 35 to 40 years ago are still functioning with good vacuums.
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