This is a reference post for lab managers, embryologists, and procurement leads who want the technical specification detail behind dry shipper selection — not a sales overview.
THE PHYSICS THAT MATTERS
A dry shipper operates in LN2 vapour phase. The inner sorbent matrix (typically zeolite-based) is charged with liquid nitrogen until fully saturated. During transport, no free liquid is present. Nitrogen vapour off-gasses from the matrix maintaining internal temperature between -150°C and -190°C depending on fill level and vessel age.
The critical biological threshold is approximately -130°C. Below this, the glassy (vitreous) state prevents ice crystal formation and biological time effectively stops. All three CryoStork models (V2, V3, V10) maintain temperature well below this threshold when correctly charged.
IATA COMPLIANCE
Dry shippers correctly charged with no free liquid nitrogen are exempt from IATA PI 650 dangerous goods restrictions. This is verified by the inversion test: hold the vessel inverted for 10 seconds post-charge. Any liquid nitrogen exiting means the charge is incomplete.
MODEL COMPARISON
CryoStork V2 — 2L — Single-patient, courier, hand-carried
CryoStork V3 — 3L — Routine inter-clinic (1-3 patients)
CryoStork V10 — 10L — Multi-patient, sperm bank, long distance
PRE-TRANSFER CHECKLIST
- Inversion test: no free LN2 after 10 seconds inverted
- Temperature log verified (calibrated data logger)
- Charge time recorded in traceability documentation
- IATA paperwork complete (air freight only)
SORBENT DEGRADATION
Sorbent material degrades over time and with repeated charge cycles. An older vessel may fail the inversion test even after a full charge. Static hold time shortens progressively as sorbent capacity reduces. This is the most common cause of unexpected temperature excursion in vessels that have passed previous transfers without issue.
Full CryoStork range: cryolab.co.uk/product-category/dry-shippers/
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