Fail-safe proportional mixing valve
AssigneeMagarl, LLC
InventorsRobert Eveleigh, Kevin Kline
Life of this patent
Estimating the term…
Abstract
A fail-safe proportional mixing valve is provided that tempers a hot fluid supply by proportional flow from a hot fluid inlet and a cold fluid inlet. The valve includes a fail-safe mechanism disposed within the body of the valve to isolate flow from the hot fluid inlet in the event the temperature of the mixed fluid exceeds a predetermined set point. The valve also includes a check valve in the fluid inlets to prevent backflow in case of failure of a fluid supply. In a further aspect, the cold fluid inlet includes an adjustment set screw to adjust the cold fluid flow into the mixing valve, thereby adjusting the maximum mixed fluid temperature that can be discharged from the valve assembly.
Claims14
A fail-safe proportional mixing valve assembly, comprising:
- a valve body defining a mixing chamber;
- a cold fluid inlet in communication with said mixing chamber and connected to a supply of a first flow of a cold fluid;
- a hot fluid inlet in communication with said mixing chamber and connected to a supply of a second flow of a hot fluid;
- a fluid outlet in communication with said mixing chamber for discharge of fluid therefrom,
- wherein said cold fluid inlet and said hot fluid inlet are proportionately sized to temper the hot fluid within said mixing chamber below a predetermined set point temperature;
- and
- failure responsive means for substantially restricting said second flow of hot fluid into said mixing chamber upon a failure of said first flow of cold fluid, said failure responsive means being at least partially disposed within said mixing chamber and including;
- a thermal expansion member disposed in said mixing chamber that volumetrically changes in proportion to the fluid temperature in the mixing chamber;
- a plug disposed between said hot fluid inlet and said mixing chamber and engaged to said thermal expansion member to move with said member from an open position which allows substantially full flow from said hot fluid inlet, to a closed position in which said plug substantially restricts flow from said hot fluid inlet;
- and
- biasing means for biasing said plug to said open position when the temperature of fluid within said mixing chamber is below said set point.
The mixing valve assembly according to clam 5, wherein said biasing means includes a second spring operating on said plug and opposing said first spring, wherein said first spring and said second spring are arranged to support said plug within said hollow interior of said mixing chamber and to maintain alignment of said plug with said hot fluid inlet.
A fail-safe mixing valve assembly, comprising:
- a valve body defining a mixing chamber;
- a cold fluid inlet in communication with said mixing chamber and connected to a supply of a first flow of a cold fluid;
- a hot fluid inlet in communication with said mixing chamber and connected to a supply of a first flow of a hot fluid;
- failure responsive means for substantially restricting said second flow of hot fluid into said mixing chamber upon a failure of said first flow of cold fluid, said failure responsive means being at least partially disposed within said mixing chamber;
- and
- a flow control member disposed within at least one inlet of said cold fluid inlet or said hot fluid inlet, said flow control member including an adjustment screw having a stepped diameter shaft, said adjustment screw being adjustably disposed within said one inlet to introduce portions of said stepped diameter shaft into the corresponding first flow or second flow through said one inlet to reduce said corresponding flow in proportion to the diameter of said portions of said shaft.
Dependencies are inferred from the claim text.