Liquid Nitrogen Level Monitor/Alarm for Ultra Low Temperature Cryogenic Dewar Freezers.
Model LD 215 Product Information.
- Application specific probe lengths for different freezer/container sizes and required liquid/vapor levels.
- Audible & visual out-of-tolerance alarms.
- SPDT alarm contact output.
- 100-ohm cryogenic RTD probe.
- 0.250-inch/6.35 mm optimum level change resolution.
- Low-level or overflow mode operation.
- User adjustable initial alert condition delay and mute periods.
- Battery backup with (2) rechargeable AA batteries included.
- Shaft collar and wrench included for probe positioning.
The Model LD 215 is designed to monitor cold storage temperature conditions within ultra low temperature (ULT) LN2 cryogenic dewar freezers. These freezers are typically used in the cryopreservation of genetic/biological materials, the cold storage of vaccines and for in vitro fertilization (IVF) biologics.
The Model LD 215 tracks the freezer cryogenic liquid nitrogen level by using a special 100-ohm cryogenic RTD probe located inside the ULT unit and just above the normal liquid/gas phase boundary. It will alert for a low LN2 level by sensing a temperature increase (due to LN2 evaporation or inflow disruption) or an LN2 overflow condition by sensing a drop in temperature.
If a high or low limit threshold is reached, the alert system activates with a flashing red LED and a pulsing beeper (an audible/visual alarm) and corrective action can be taken before cold storage materials become compromised. If the probe is disconnected (or indicates an open) a red LED and beeper will activate. The alert system can also be set to mute for a period of up to 60 minutes. An auto dialing option is also available for any alarm condition triggered.
The cryogenic RTD sensor probe used for level indication is typically positioned approximately 1/4-inch from the ideal LN2 liquid level (to minimize the potential for frost accumulation on the probe). Once optimum sensor position is established and the alarm thresholds are set, the unit is ready to continuously monitor and alert.
The LD 215 is shipped with a plug-in power supply and a battery backup. Single pole alarm relay double throw (SPDT) contacts are brought out to tool-less spring-loaded connectors.
- Auto Dialer: (Model AD 2000) Dials a phone/pager to immediately provide alarm notification whenever a set alarm level is triggered.
- Remote Alarm Delay Module (Model ADM 215 with Audible & Visual Alarm Indication.