Patent ID: 6042015
Filing Date: 2000-03-28
Classification: G05D,Y10S

Abstract:
A fail-safe proportional mixing valve assembly, comprising:a valve body having a cylindrical portion defining a mixing chamber and a longitudinal axis;a cold fluid inlet in communication with said mixing chamber and connectable to a supply of a first flow of a cold fluid;a hotter fluid inlet in communication with said mixing chamber along said longitudinal axis and connectable to a supply of a second flow of a relatively hotter fluid;a fluid outlet in communication with said mixing chamber for discharge of fluid therefrom; andmeans for substantially restricting said second flow of hotter fluid into said mixing chamber when the temperature of the fluid in said mixing chamber exceeds a predetermined set point temperature, said means including;thermally responsive member disposed in said mixing chamber that moves in proportion to the fluid temperature in said mixing chamber;a plug disposed between said hotter fluid inlet and said mixing chamber and engaged to said thermally responsive member to move with said member,wherein said thermally responsive member is operable to move said plug along said longitudinal axis between an open position which allows substantially full flow from said hotter fluid inlet into said mixing chamber, and a closed position in which said plug substantially restricts flow from said hotter fluid inlet when the fluid temperature in said mixing chamber exceeds said set point temperature; andbiasing means for biasing said plug away from said closed position when the temperature of fluid within said mixing chamber is below said set point temperature.