StarWatch™ Cryogenic Monitoring System

Stop Guessing About Your Cryogenic Liquid Supply Levels

You rely on portable, pressurized cryogenic liquid dewars to supply liquid or gaseous nitrogen, argon, and carbon dioxide to your lab. The float gauges traditionally found on these dewars are prone to inaccuracy or failure, leaving users uncertain about how much liquid is available to supply their applications. To avoid untimely product outage, many labs return dewars with as much as 20 percent unused product, wasting money and decreasing productivity.

The StarWatch™ Cryogenic Monitoring System – available exclusively from Linde – provides a clear digital read-out of the liquid level and pressure in your dewar and alerts you with an audio and visual alarm when your supply runs low. The capacitance-based measurement of the StarWatch system provides a leap forward in reliability and accuracy versus conventional float gauges.

Praxair StarWatch System


When the StarWatch system detects the dewar supply to be at or below your alarm levels, the corresponding conditions are displayed on the LCD, and the audiovisual alarms are activated until acknowledged by the user with a single push of a button. When a new low alarm condition is met, corresponding displays and alarms are activated again. Low and critically low alarms have distinct frequencies, so you can quickly assess your dewar and take action as necessary. The StarWatch system offers options to disable either the alarms alone or the measurements and alarms together during periods of process inactivity.

The StarWatch system comes equipped on Linde’s ProSpec™ cryogenic dewars – high quality liquid packages dedicated to laboratory applications and optimized for either low (liquid) or high (gas) pressure service. The reliable ProSpec dewar, combined with the StarWatch system’s accurate level and pressure reporting, allows you to stay focused on your work, avoiding process interruptions from product outages and the waste associated with residual returns.

System Features

  • Audible and visual alarm beacon.
  • Clear and easy-to-read liquid-crystal display (LCD). Shows the liquid level (percent) and pressure (psi) in the dewar and indicates whether any alarms are active.
  • Connection to electronic pressure gauge on liquid dewar.
  • Buttons to customize alarm set points. There are four different alert levels: low liquid level, critically low liquid level, low pressure, and critically low pressure.

Features and Benefits

Easy-to-read, digital liquid level and pressure indicator

  • Always know the supply level and pressure in your dewar
      ± 2 percent (liquid)
      ± 1 psi (up to 60 psig service)
      ± 5 psi (up to 500 psig service
  • Reduce the risk of product outages
  • Minimize return of unused liquid

Adjustable low and critically low level alarms

  • Customize alert levels to your application and operations
  • Enhance security against product outage

Audible and visual alarm indicators

  • Recognize alarm condition through two different modes of alert

Dedicated low or high pressure service

  • Select dewars with pressure adjustment system suited to your application
  • Minimize product losses from safety relief valve venting during liquid service