Defrost indicator

Abstract

A defrost indicator is configured such that the process of freezing and defrosting the defrost indicator places the defrost indicator into a state that is not completely reversed by refreezing, so that one can detect whether the defrost indicator defrosted and refroze or never defrosted by observing its current state. In an embodiment, the defrost indicator is initially placed in a first state before being frozen (e.g., upside down with fluid in an upper chamber). Freezing the defrost indicator places it in a second state (e.g., with the fluid frozen in the upper chamber). Then when the defrost indicator is defrosted, the defrost indicator is placed into a third state that is different than the first state (e.g., right-side-up with liquid fluid in the lower chamber). If the defrost indicator is again frozen, the defrost indicator is placed into a fourth state (e.g., the fluid frozen in the lower chamber).

1 . A device comprising:
 an indicator that has at least two states that are visibly distinct from one another,   a first of the two states occurs when the indicator is initially frozen and   a second of the two states occurs as a result of the indicator defrosting and refreezing.   
   
   
       2 . The device of  claim 1 , the indicator including a container having two chambers,
 in the first of the two states, the a fluid is frozen and located within a first of the two portions of the container, and   in the second of the two states at least some of the fluid that was in the first of the two portions of the container is now in a second of the two portions of the container.   
   
   
       3 . The device of  claim 2 , the two portions of the container being two chambers, and the container having a shelf that supports the frozen fluid while the fluid is frozen, but the shelf is permeable to fluids and allows the fluid that melts to move to the second chamber. 
   
   
       4 . The device of  claim 2 , the two portions of the container being two chambers, and the container having a shelf that supports the frozen fluid while the fluid is frozen, but the shelf has a hole that allows the fluid that melts to fall to the second chamber. 
   
   
       5 . The device of  claim 2 , the container having side walls that are slanted forming a top portion that is wider than a lower portion, in the first state the frozen fluid is located in the top portion and is held in the top portion as a result of being frozen to a shape that is too wide to fit in the lower portion. 
   
   
       6 . The device of  claim 2 , the container having side walls that are jagged in at least a top portion, in the first state the frozen fluid is located in the top portion and is held in the top portion as a result of being frozen to a shape that is engages the jagged surface of the top portion. 
   
   
       7 . The device of  claim 2 , the container being an inner container, the device further comprising:
 an outer container; and   
     the inner container being mounted within the outer container. 
   
   
       8 . The device of  claim 7 , the outer container having a window through which the first of the two portions is visible. 
   
   
       9 . The device of  claim 2 , the fluid being colored. 
   
   
       10 . The device of  claim 2 , the fluid being saline solution. 
   
   
       11 . The device of  claim 2 , the fluid including a coloring and Sodium Cloride (ppm) 2100-1750. 
   
   
       12 . The device of  claim 1 , the device comprising:
 a container having walls, the walls including a strong portion and a weak portion;   the strong portion is strong enough that the strong portion is expected not to crack as a result of freezing the container while full with a fluid; and   the weak portion is weak enough so that the weak portion is expected to crack when the container is frozen while full with the fluid.   
   
   
       13 . The device of  claim 12 , the container having a window via which one can see whether the fluid leaked out of the container. 
   
   
       14 . The device of  claim 12 , the container having a portion of the walls that is made from a self sealing material. 
   
   
       15 . The device of  claim 1 , the indicator including at least
 a fluid   an inner container within which the fluid is stored, the inner container having walls of a thickness and of a material that is expected to crack when the fluid within is frozen for the first time; and   an outer container in which the inner container is stored; the outer container include walls having at least a portion through which the inner container may be viewed.   
   
   
       16 . A device comprising a container having a support for frozen fluid that
 holds the fluid in first location, associated with the support, and holds the fluid in the first location as long as the fluid remains frozen, and   allows the fluid to flow to another location as the fluid melts.   
   
   
       17 . A method comprising:
 freezing a fluid in a location where the fluid is supported as long as the fluid remains frozen, and   allowing the fluid to flow away from the location as the fluid melts.   
   
   
       18 . The method of  claim 17  further comprising:
 checking whether the frozen liquid is still in the location where the fluid is supported as long as the fluid remains frozen, and determining whether the defrost indicator defrosted based on whether the frozen liquid is still in the location where the fluid is supported as long as the fluid remains frozen.   
   
   
       19 . A method comprising:
 forming an indicator by at least   forming an a first location within the indicator where the frozen fluid is initially stored;   forming a second location with the indicator where the fluid flows to when the fluid melts;   forming a transparent portion on the indicator, via which the frozen fluid in the container may viewed; and   placing a liquid within the indicator in the first location.