Patent ID: 7175100

Claim:
A fail-safe mixing valve assembly, comprising: a valve body defining a longitudinal axis; a cold fluid inlet for receiving a first flow of fluid; a hot fluid inlet for receiving a second flow of fluid and aligned with the longitudinal axis; a mixing chamber within the valve body and in variable fluid communication with the cold fluid inlet and the hot fluid inlet; a fluid outlet in fluid communication with the mixing chamber for discharge of fluid therefrom; a plug disposed within the valve body; a first spring operably connected to the plug for biasing the plug toward a first position wherein fluid is allowed to flow through the hot fluid inlet into the mixing chamber, the first spring concentrically disposed about at least a portion of the plug when the plug is in the first position; a second spring operably connected to the plug for biasing the plug toward a second position wherein fluid is allowed to flow through the hot fluid inlet into the mixing chamber; and a thermostatic member operable to cause compressive force to be applied to both the first spring and the second spring to move the plug along the longitudinal axis in a direction from the first position toward the second position in response to the temperature of fluid within the mixing chamber thereby reducing the flow rate of fluid through the hot fluid inlet.