possible so long as the closed system provides for the pulsatile delivery of cryogen to the cryoprobe as such any single or multiple configurations of cryoprobes or catheters may be used such instruments may also include cryoguns or cryodevices for rapid cryo delivery processes or cryotherapies as illustrated in fig5 a cryogenic system 60 also known as cryoengine 60 has a two cylinder configuration the system of which is divided into two subassemblies i those components above the cover 61 and ii those components below the cover all of the components below the cover are contained in a liquid nitrogen dewar and immersed in liquid nitrogen at atmospheric pressure bp u2212 196 u00b0 c during operation to understand the operational features of the cryoengine and method of production and transport of supercritical nitrogen scn a brief description of cryogen flow follows upon filling the dewar not pictured with liquid nitrogen from an external source an immersible liquid cryogen pump 79 is activated to fill each cryogen supply cylinder 2 a amp 2 b or cartridge sequentially initially one cartridge 2 a is filled along with its linked cryogen pressurization cartridge 3 a cryogenic solenoid valves provide venting of the gas within the cartridge assembly to support filling upon completion.