Back-up or fail-safe monitoring, data recording, temperature control system for refrigerators or chilled spaces or apparatus for storing biological material such as vaccines

摘要

Disclosed are control means for a refrigerator for maintaining internally stored biological materials within known upper and lower temperature storage limits. The refrigerator includes a heat pump driven by a supply of electricity in series with a first thermally sensitive electric power switch capable of closing and thereby applying power to the heat pump if the temperature rises above a first predetermined temperature or of opening and disconnecting the power if the temperature falls below the first predetermined temperature. The first power switch is placed electrically in series with a second thermally sensitive electric power switch, also responsive to the temperature of the storage space by closing if the temperature rises above a second predetermined temperature or opening if the temperature falls below a second predetermined temperature. The second predetermined temperature is less than the first predetermined temperature so that the contacts of the second electric power switch are conserved yet can act to protecting the biological materials from undue cold if the first switch should become always closed.