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The LD-215 Liquid Nitrogen Level Monitor/Alarm from Hampshire Controls tracks liquid nitrogen levels in cryogenic storage systems with a monitoring depth from 2 to 24 inches. It uses a cryogenic RTD sensor placed inside the Dewar, positioned just above or just below the liquid nitrogen and gas phase boundary. The temperature monitoring system responds to changes in LN₂ level, allowing the system to react when liquid nitrogen is lost or when liquid nitrogen immersion conditions change. These condition monitoring systems are commonly used in cryogenic storage environments where consistent LN₂ level monitoring is required for the safe storage of biological materials.
Product Overview and Function
The LD-215 employs a 100-Ohm cryogenic RTD housed in a stainless-steel probe with a variable application-specific length. The probe detects liquid nitrogen level through temperature change: when LN₂ evaporates and the level drops below the probe tip, temperature rises and the system activates an alert. When operating in overflow mode, immersion of the probe tip in LN₂ triggers the opposite response, activating an alert when temperature drops.
The probe supports customer-specified depths between 2 and 24 inches (between 51 and 610 mm), with resolution of 0.25 inches (6 mm) and a sampling interval of approximately 4 seconds. The system allows calibration through a simple pushbutton interface. The LD-215 is easy to use for both laboratory and clinical use.
Alarm Logic and Output Control
The LD-215 supports both low-level and overflow detection modes. Low-level alarm activates when the probe tip is no longer immersed in liquid nitrogen. High-level or overflow alarm activates when the probe tip becomes immersed in liquid nitrogen.
Alarm delay settings are adjustable at 0, 30 seconds, 1 minute, 5 minutes, 10 minutes, and 30 minutes. Audible alarm mute options are available from 5 to 60 minutes, depending on operational requirements. A Single Form C (SPDT) dry contact relay output allows connection to external alarm panels or notification systems with NO or NC configuration.
Sensor, probe, and Build
The 100-Ohm cryogenic RTD sensor is fitted into a stainless-steel sheath with PTFE-jacketed leads. Standard lead length is 10 ft (3m). probe length and configuration are adjusted based upon the Dewar designs, including optional 90-degree bends for side mounting over container lips. A shaft collar and wrench are included for correct positioning inside Dewars and other LN2 storage vessels.
Power System
The LD-215 operates with a 100–240V AC input and a 12V DC output power adapter rated at 0.6A (7.2W). It supports 50–60 Hz frequency and uses a UL-listed 2-prong US plug. A dual AA NiMH rechargeable battery backup system (2500 mAh) with built-in trickle charger provides approximately 12 hours of operation.
Key Features and Operation
The LD-215 monitors LN₂ levels continuously at a resolution of 0.25 inches (6 mm). It supports selectable alarm delays, mute periods, and relay output control for external systems. Visual indicators and audible alerts activate when conditions shift outside user established parameters. probe calibration is handled through onboard pushbutton controls. The LD-215 is designed for direct integration into existing monitoring systems in cryogenic storage environments.
Applications and Product Positioning
The LD-215 is used in cryogenic storage systems supporting IVF clinics, biomedical laboratories, vaccine storage units, and biobanking facilities. It is part of Hampshire Controls’ product line alongside Multi-probe Cryogenic Temperature Monitor/Alarms.
The LD-215 fits within broader condition monitoring systems used in laboratory and clinical storage environments, working alongside temperature monitoring systems where consistent environmental visibility is required for stored samples.
Custom Options and Service Support
Available configurations include custom probe depths from 2 to 24 inches (51 to 610 mm), alternate probe configurations, and optional mounting brackets. Relay output configuration and alarm behavior can be adjusted based on application requirements. Hampshire Controls also provides temperature calibration services to support long-term accuracy across installed systems and connected temperature monitoring systems.
Stop Guessing, Start Knowing Your LN₂ Levels
Don’t wait for a thawed sample or a surprise tank overflow. The LD-215 Liquid Nitrogen Level Monitor/Alarm gives you direct, real-time visibility where it matters most. Get in touch with Hampshire Controls to configure your setup, request pricing, or match the LD-215 to your storage system.