Variable flow valve

A fluid flow control device primarily intended for throttling the flow of liquid refrigerant between two flow rates. The device includes a disc which moves between two distinct positions with a snap action in response to changes in temperature of the refrigerant. The disc is connected at its center to a stem member having an axial bore aligned with and of smaller cross-sectional area than the outlet passage of a flow chamber wherein the disc and stem are positioned. When refrigerant temperature increases to a predetermined level, the disc moves the stem into contact with the chamber wall surrounding the outlet orifice, thereby limiting refrigerant flow to that which passes through the relatively smaller bore of the stem member. When refrigerant temperature drops sufficiently, the disc snaps back to the other position, moving the end of the stem away from the outlet orifice to permit flow at a higher rate. A pre-tensioning arm is also provided for placing a biasing force on the disc in one position thereof to control more precisely the temperature at which it moves to the other position.

What is claimed is:

1. A temperature-responsive fluid flow control device comprising:

(a) a body portion defining an enclosed chamber, and inlet and outlet passages or predetermined cross-sectional areas for flow of a fluid into and out of said chamber, respectively;

(b) flow control means positioned within said chamber and movable between first and second positions, wherein flow through said body portion is established through passages of first and second cross sectional areas, respectively, said flow control means comprising an elongated stem member having an axial bore extending therethrough and an end portion movable into and out of engagement with an internal wall of said enclosed chamber when said control means is in said first and second positions, respectively, said end portion being in covering relation to one of said inlet and outlet passages with said axial bore in alignment therewith when in engagement with said internal wall to limit flow through said covered passage to that flowing through said axial bore;

(c) a circular disc positioned within said chamber and movable between two distinct positions with a snap action in response to the temperature of said disc as determined by the temperature of fluid within said chamber, said disc being supported at its periphery in a substantially fixed position, whereby movement of said disc between said two distinct positions occurs at the center of said disc; and

(d) means connecting said disc at its center to said flow control means to move said control means between said first and second positions in response to respective movement of said disc between said two distinct positions thereof.

2. The invention according to claim 1 wherein said axial bore has a cross-sectional area less than said predetermined cross-sectional area of said covered passageway.

3. The invention according to claim 2 wherein said covered passage is said outlet passage.

4. A temperature-responsive fluid flow control device comprising:

(a) a body portion defining an enclosed chamber, and inlet and outlet passages of predetermined cross-sectional areas for flow of a fluid into and out of said chamber, respectively;

(b) flow control means positioned within said chamber and movable between first and second positions, wherein flow through said body portion is established through passages of first and second cross-sectional areas, respectively, said flow control means comprising an elongated stem member having opposite end portions and an axial bore of cross-sectional area less than said predetermined cross-sectional area of said outlet passage extending therethrough, one of said end portions being movable into and out of covering relation to said outlet passage when said control means is in said first and second positions, respectively, said axial bore being in alignment with said outlet passage, whereby fluid flow through said outlet passage is limited to that flowing through said bore when said control means is in said first position;

(c) a circular disc positioned within said chamber and movable between two distinct positions with a snap action in response to the temperature of said disc, as determined by the temperature of fluid within said chamber, said disc having an essentially flat configuration in one and slightly dome-shaped configuration in the other of said two distinct positions and being supported at its periphery in a substantially fixed position, whereby movement of said disc between said two distinct positions occurs at the center of said disc;

(d) means connecting said disc at its center to said flow control means to move said control means between said first and second positions in response to respective movement of said actuating means between said two distinct positions thereof; and

(e) adjustable biasing means constructed and arranged to exert a force on said disc when the latter is in said dome-shaped configuration, thereby providing a predetermined biasing force tending to move said disc toward said first configuration.

5. The invention according to claim 4 wherein said biasing means comprises an arm having an end portion in contact with the end portion of said stem member opposite said one end portion.

6. A temperature-responsive fluid flow control device comprising:

(a) a body portion defining an enclosed chamber, and inlet and outlet passages of predetermined cross-sectional areas for flow of a fluid into and out of said chamber;

(b) flow control means positioned within said chamber and movable between first and second positions, wherein flow through said body portion is established through passages of first and second cross-sectional areas, respectively, said flow control means comprising an elongated stem member having opposite end portions, said disc being connected at its center to said stem member intermediate of said end portions,

(c) a circular disc positioned within said chamber and movable between two distinct positions with a snap action in response to the temperature of said disc, as determined by the temperature of fluid within said chamber, said disc being supported at its periphery in a substantially fixed position, whereby movement of said disc between said two distinct positions occurs at the center of said disc;

(d) means connecting said disc at its center to said flow control means to move said control means between said first and second positions in response to respective movement of said disc between said two distinct positions thereof; and

(e) biasing means comprising an arm having a first end fixedly connected with respect to said body portion and a second, free end constructed and arranged to exert a biasing force on said disc when the latter is in one of said two distinct positions, said free end of said arm contacting one of said end portions of said stem member to apply said biasing force to said disc through said stem member.

7. The invention according to claim 6 and further including means for selectively adjusting said biasing force.

8. The invention according to claim 7 wherein said one end of said arm is fixedly connected with respect to said body portion by means of a threaded connection, and said means for selectively adjusting said biasing force comprises the relative degree of tightening of said threaded connection.

9. The invention according to claim 6 and further including an annular retaining element threadedly engaged with said body portion, said disc being supported at its periphery between said retaining element and a shoulder on said body portion within said chamber.

10. The invention according to claim 9 and further including a threaded stud on said retaining element whereon said one end of said arm is retained by a nut.