SEMIFLEX® is vacuum-insulated stainless steel piping for liquid nitrogen supply made by Vacuum Barrier Corporation. It is available with sealed or dynamic vacuum and keeps heat losses minimal during cool-down and in steady state. In a system with phase separators, SEMIFLEX delivers single-phase low-pressure LN2 to each point of use.
| Component | Purpose |
|---|---|
| SEMIFLEX | Stainless steel vacuum pipe; sealed or dynamic vacuum |
| ES SEMIFLEX | Flexible vacuum piping for main lines, with protective layer |
| CobraFlex | Flexible hose with sealed vacuum and outer braid |
| Triax | Combined with SEMIFLEX, eliminates two-phase flow to all points of use |
| Phase separator with modulating valve | Pneumatic; dynamic or sealed vacuum; 2, 4 or 8 outlets |
| Sensor-controlled phase separator | Vapour separation and single-phase LN2 delivery |
| NITROMATIC Dewar Fill | Automatic filling of a dewar or vessel from a pipeline or outdoor tank |
Source: Vacuum Barrier Corporation, VBS Europe.
In a vacuum pipe, liquid nitrogen travels as a two-phase flow — liquid with vapour. If vapour enters the doser, dose weight becomes unstable. A phase separator removes the vapour and supplies low-pressure liquid nitrogen to the point of use on demand. The combination of SEMIFLEX and Triax eliminates two-phase flow to all points.
In the sealed version, the vacuum is created at the factory and retained in the insulating space. In the dynamic version, the vacuum is maintained by pumping. SEMIFLEX, ES SEMIFLEX and phase separators with modulating valve are available in both versions; CobraFlex — sealed vacuum only. The version is chosen when the line is designed.
Yes, a doser can be fed from a portable dewar. Piping from an outdoor tank is used for continuous line operation and several points of use.
Location of the tank and points of use, route length, number of dosers and operating mode. Piping, separators and flexible sections are selected based on this data.
