05509436 is referenced by 28 patents and cites 25 patents.

An exhalation valve 14 for a filtering face mask 10 has a flexible flap 24 that makes contact with a curved seal ridge 30 of a valve seat 26 when the valve 14 is in the closed position. The curvature of the seal ridge 30 corresponds to a deformation curve exhibited by the flexible flap 24 when secured as a cantilever at one end and exposed at its free portion to a uniform force and/or a force of at least the weight of the free portion of the flexible flap. A seal ridge curvature corresponding to a flexible flap exposed to uniform force allows the flexible flap 24 to exert a generally uniform pressure on the seal ridge to provide a good seal. A seal ridge curvature corresponding to a flexible flap exposed to a force of at least the weight of the flap's free portion allows the flexible flap 24 to be held in an abutting relationship to the seal ridge 30 under any static orientation by a minimum amount of force, thereby providing a face mask 10 with an extraordinary low pressure drop during an exhalation.

Title
Unidirectional fluid valve
Application Number
891289
Publication Number
5509436
Application Date
May 23, 1995
Publication Date
April 23, 1996
Inventor
Anthony B Ferguson
Woodbury
MN, US
Harold J Seppala
St. Paul
MN, US
Vaughn B Grannis
Inver Grove Heights
MN, US
Daniel A Japuntich
St. Paul
MN, US
Agent
Karl G Hanson
Walter N Kirn
Gary L Griswold
Assignee
Minnesota Mining and Manufacturing Company
MN, US
IPC
F16K 15/16
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