Patent ID: 6973894

Claim:
A timing device for determining the passage of a preselected period of time comprising: (a) a tube having opposed ends with one of the opposed ends extending downwardly below the level of the remaining portion of the tube, one of said opposed ends having a first reservoir for storing a reactant or an indicator, the other of said reactant or indicator being stored in the tube but not in the, first reservoir, said tube undergoing at least two material changes in direction from one of the opposed ends to the other; (b) transport means extending from the reservoir to the other of the opposed ends of the tube for transporting at least one of the reactant or the indicator until they contact each other; (c) said reactant; and (d) said indicator which when in contact with the reactant via the transport means emits an observable change in a property wherein the minimum length of the period of time corresponds to the time it takes for the reactant and indicator to contact each other.