Erschienen in:
05.03.2019 | Assisted Reproduction Technologies
Early detection of cryostorage tank failure using a weight-based monitoring system
verfasst von:
Zahava P. Michaelson, Sai T. Bondalapati, Selma Amrane, Robert W. Prosser, Daniel M. Hill, Pallavi Gaur, Matt Recio, David E. Travassos, Mikaela D. Wolfkamp, Sasha Sadowy, Colin Thomas, Eric J. Forman, Zev Williams
Erschienen in:
Journal of Assisted Reproduction and Genetics
|
Ausgabe 4/2019
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Abstract
Purpose
To study the relationship between liquid nitrogen loss and temperature in cryostorage dewars and develop an early-warning alarm for impending tank failure.
Methods
Cryostorage dewars were placed on custom-engineered scales, and weight and temperature data were continuously monitored in the setting of slow, medium, and fast rate-loss of LN2 to simulate three scenarios of tank failure.
Results
LN2 Tank weights and temperatures were continuously monitored and recorded, with a calculated alarm trigger set at 10% weight loss and temperature of − 185 °C. With an intact tank, a 10% loss in LN2 occurred in 4.2–4.9 days. Warming to − 185 °C occurred in 37.8–43.7 days, over 30 days after the weight-based alarm was triggered. Full evaporation of LN2 required ~ 36.8 days. For the medium rate-loss simulation, a 10% loss in LN2 occurred in 0.8 h. Warming to − 185 °C occurred in 3.7–4.8 h, approximately 3 h after the weight-based alarm was triggered. For the fast rate-loss simulation, a 10% weight loss occurred within 15 s, and tanks were depleted in under 3 min. Tank temperatures began to rise immediately and at a relatively constant rate of 43.9 °C/h and 51.6 °C/h. Temperature alarms would have sounded within 0.37 and 0.06 h after the breech.
Conclusions
This study demonstrates that a weight-based alarm system can detect tank failures prior to a temperature-based system. Weight-based monitoring could serve as a redundant safety mechanism for added protection of cryopreserved reproductive tissues.