Patent ID: 6260996
Filing Date: 2001-07-17
Classification: G04B

Abstract:
An hourglass comprising:a first reservoir having a collecting end and a transfer end, the transfer end being smaller than the collecting end;a second reservoir having a collecting end and a transfer end, the transfer end being smaller than the collecting end;a necked duct extending between the transfer end of said first reservoir and the transfer end of said second reservoir, the necked portion providing a restricted fixed flow path between the first reservoir and the second reservoir; anda bypass duct extending between the collecting end of said first reservoir and the collecting end of said second reservoir, the bypass duct having a valve that allows capture of an amount of material used to measure time with the hourglass, so that the amount of granular material held in said first reservoir will flow from the first reservoir through the transfer end of said first reservoir through the necked duct and into the transfer end of said second reservoir when said first reservoir is placed over said second reservoir, and so that granular material held near the collecting end of said second reservoir is transferred to the bypass duct and retained in the bypass duct by the valve by tilting the second reservoir to allow the granular material to enter the bypass duct, so that the granular material held in the bypass duct by the valve is used as reference for comparisons of time measurements and flow through the bypass duct to the collecting end of the first reservoir.