# Patent

## Title
Thermostatic expansion valve with check valve

## Abstract

A valve is provided that comprises a valve body including an inlet, an outlet, and a check valve chamber having an opening through the side of the valve body. The valve has a cover secured within the side opening in the valve body. A first valve opening is disposed between the inlet chamber and outlet chamber. A control valve is movable relative to the first valve opening to regulate fluid flow through the first opening when fluid flow is in the inlet-to-outlet direction, and is movable to engage the first valve opening to restrict fluid flow in the outlet-to-inlet direction. The valve comprises a passageway between the inlet and check valve chambers, and a second valve opening disposed between the check valve and outlet chambers. A check valve is disposed within the check valve chamber, and is movable relative to the second valve opening to restrict forward flow and permit reverse flow through the second valve opening.

## Background
FIELD OF THE INVENTION
The present invention relates to thermostatic expansion valves for controlling the flow of refrigerant to an evaporator.
BACKGROUND OF THE INVENTION
Thermostatic expansion valves are used to control or meter the flow of refrigerant to an evaporator in an air conditioning system, to provide a refrigerant flow rate into the evaporator that approximately matches the refrigerant flow exiting the evaporator. The thermostatic expansion valve typically permits fluid flow from the inlet to the outlet during normal operation of the air conditioning system, where the fluid at the inlet is typically at a higher pressure than the fluid at the outlet. Where the air conditioning system also functions as a heat pump in which refrigerant flow is reversed, a check valve is typically plumbed in parallel to the expansion valve to permit refrigerant flowing in a direction opposite that of the typical expansion valve to bypass the valve.
SUMMARY OF THE INVENTION
The present invention relates to a thermostatic expansion valve that has a first valve element that is movable to regulate fluid flow through the valve from the inlet to the outlet. The thermostatic expansion valve also has a second passage for permitting fluid flow through the valve from the outlet to the inlet when fluid flow is in a reverse direction. According to one aspect of the present invention, one embodiment of a valve for control of fluid flow is provided that comprises a valve body including an inlet chamber, an outlet chamber, and a check valve chamber having an opening through the side of the valve body. The valve includes a cover member secured within the opening in the side of the valve body, which is configured to seal off the check valve chamber. The valve comprises a first valve opening disposed between the inlet chamber and outlet chamber, and a control valve element movable relative to the first valve opening to regulate fluid flow from the inlet through the outlet when fluid flow is in the inlet-to-outlet direction. The control valve element is further movable to engage the first valve opening when fluid flow is in the outlet-to-inlet direction to restrict fluid flow through the first valve opening to the inlet.
The valve further comprises a passageway between the inlet chamber and the check valve chamber, and a second valve opening disposed between the check valve chamber and outlet chamber. A check valve member is disposed within the check valve chamber, and is movable relative to the second valve opening. When fluid flow is in the inlet-to-outlet direction, the control valve permits fluid flow to the outlet, and the check valve is movable to restrict fluid flow from through the second valve opening to the outlet. When fluid flow is in the outlet-to-inlet direction, the check valve is movable away from the second valve opening to permit fluid flow from the outlet chamber through the second valve opening and passage to the inlet. In reverse flow situations, the check valve plate is movable away from the second valve opening to permit fluid flow from the outlet through the second valve opening and passage to the inlet. In forward flow situations, the fluid flows through the first control valve and the check valve is movable toward the second valve opening so as to not permit fluid flow through the second valve opening to the outlet.
In another aspect of the present invention, a second embodiment of a valve for control of fluid flow is provided that comprises a passageway between the inlet chamber and the check valve chamber, where the passageway is entirely disposed within the valve body. A second valve opening is disposed between the check valve chamber and outlet chamber, and a check valve plate is disposed within the check valve chamber and is movable relative to the second valve opening. When fluid flow is in the inlet-to-outlet direction, the check valve plate is movable to restrict fluid flow from the inlet through the second valve opening. When fluid flow is in the outlet-to-inlet direction, the check valve plate is movable away from the second valve opening to permit fluid flow from the outlet chamber through the second valve opening around the outer periphery of the check valve plate and through the passage to the inlet. In reverse flow situations, the check valve plate is movable away from the second valve opening to permit fluid flow from the outlet through the second valve opening and passage to the inlet. In forward flow situations, the fluid flows through the first valve opening and the check valve plate is movable toward the second valve opening so as to not permit fluid flow through the second valve opening to the outlet.
Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.



BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein:
FIG. 1 is a cross-sectional side view of one embodiment of a thermostatic expansion valve in accordance to the principles of the present invention;
FIG. 2 is a cross-sectional side view of a second embodiment of a thermostatic expansion valve in accordance to the principles of the present invention;
FIG. 3 is a cross-sectional side view of a third embodiment of a thermostatic expansion valve in accordance to the principles of the present invention; and
FIG. 4 is a cross-sectional side view of a fourth embodiment of a thermostatic expansion valve in accordance to the principles of the present invention.



Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings.
DETAILED DESCRIPTION OF THE EMBODIMENTS
The following description of the various embodiments are merely exemplary in nature and are in no way intended to limit the invention, its application, or uses.
One embodiment of a thermostatic expansion valve in accordance with the present invention is generally shown in FIG. 1 at 20. The thermostatic expansion valve 20 comprises an inlet 22, an outlet 24, a first valve opening 26 between the inlet 22 and outlet 24, and a first control valve element 28 movable relative to the valve opening 26 to regulate fluid flow through the expansion valve 20 when fluid flow is in the inlet-to-outlet direction as would typically occur during normal air conditioner operation. The control valve element 28 is in connection with a diaphragm that is movable in response to fluid pressure changes, which movement regulates the flow through the valve opening 26. The control valve element 28 is also movable to sealingly engage the first valve opening 26 when fluid flow is in the outlet-to-inlet direction, such that fluid flow in a reverse direction through the first valve opening 26 is prevented.
The thermostatic expansion valve 20 further comprises a passageway 30 entirely disposed within the valve body. The passageway 30 extends from the valve outlet chamber 24 to a second valve opening 32 that is in communication with the inlet chamber 22. The valve 20 comprises a second valve element 34 that is movable relative to the second valve opening 32. The second valve element 34 is movable relative to the second valve opening 32 to restrict fluid flow through the second valve opening 32 when fluid flow is in the inlet-to-outlet direction. The second valve element 34 is also movable to permit fluid flow through the passageway 30 and second valve opening 32 when fluid flow is in the outlet-to-inlet direction.
In one embodiment, the second valve element 34 functions as a check valve, and comprises a generally circular or disk-shaped plate. When fluid flow through the valve 20 is in the inlet-to-outlet direction, the fluid pressure against the second valve element or check valve plate 34 moves the check valve plate 34 against the second valve opening 32. The check valve plate 34 is adapted to engage the second valve opening 32 to substantially restrict or prevent the flow of fluid from the inlet chamber 22 through the second valve opening 32 and passage 30 towards the outlet chamber 24. Thus, the check valve plate 34 does not permit fluid flow from the inlet 22 through the second valve opening 32 to the outlet 24.
When fluid flow through the valve 20 is in the outlet-to-inlet direction, the fluid pressure against the check valve plate 34 moves the check valve plate 34 away from the second valve opening 32. The check valve plate 34 further comprises at least one opening, through which fluid may pass when the check valve plate 34 has moved away from the second valve opening 32 to a an open position. The valve 20 further comprises a retaining member 36 that is adapted to be secured within the valve to limit the movement or travel of the check valve plate 34 relative to or away from the second valve opening 32. The retaining member 36 is preferably a plate that includes at least one opening through which fluid may pass when the check valve plate 34 is in a position to permit fluid flow through the second valve opening 32. The retaining plate 36 is preferably configured to be secured within the valve body 20 by a means selected from one of a group consisting of an interference press fit, an adhesive, an ultrasonic weld, or a weld. Thus, in reverse flow situations, the check valve moves away from the second valve opening 32 towards the retaining plate 36, in which position reverse fluid flow is permitted from the outlet 24 through the passage 30 to the second valve opening 32, through the at least one opening in the check valve plate 34 and retaining plate 36, and to the inlet 22.
In a second embodiment shown in FIG. 2, the thermostatic expansion valve 20′ comprises a valve body having an inlet chamber 22, an outlet chamber 24, a side chamber 40, and a passageway 30 between the inlet chamber 22 and the side chamber 40. The passageway 30 is entirely disposed within the valve body, and may be oriented perpendicularly to the side chamber 40. Alternatively, the passageway may also be oriented at an angle relative to the side chamber for purposes of simplifying the manufacturing of the valve.
The second embodiment comprises a first valve opening 26 disposed between the inlet chamber 22 and outlet chamber 24, and also a control valve element 28 movable relative to the first valve opening 26 to regulate fluid flow from the inlet 22 through the outlet 24 when fluid flow is in the inlet-to-outlet direction. The control valve element 28 is in connection with a diaphragm that is movable in response to fluid pressure changes, which movement regulates the flow through the valve opening 26. The control valve element 28 is further movable to engage the first valve opening 26 when fluid flow is in the outlet-to-inlet direction, to substantially restrict or prevent the reverse flow of fluid through the first valve opening 26 when fluid flow is in the outlet-to-inlet direction. Thus, the first valve element 28 does not permit fluid flow from the outlet 24 through the first valve opening 26 to the inlet 22.
The second embodiment 20′ comprises an opening 32 disposed between the side chamber 40 and inlet chamber 22, and a movable check valve plate 34. The valve 20′ further comprises a retaining member 36 that is adapted to be secured within the side chamber 40 in the valve body, to limit the movement or travel of the check valve plate 34 between the opening 32 and the retaining member 36. The retaining member 36 is preferably a plate that includes at least one opening 38 through which fluid passes when the check valve plate 34 is in a position to permit fluid flow. The retaining plate 36 is preferably configured to be secured within the valve body 20′ by a cover plate 42 having a projection for abutting the retaining plate 36, as shown in FIG. 2. The cover 42 is secured to the valve body for enclosing and sealing off the side chamber 40. The cover plate 42 is preferably configured to be secured within the side chamber 40 of the valve body by a means selected from one of a group consisting of an interference press fit, an adhesive, an ultrasonic weld, or a weld.
In the second embodiment, the check valve element 34 is movable relative to the at least one opening 38 in the restriction plate 36 to restrict fluid flow through the passage 30 and opening 32 when fluid flow is in the inlet-to-outlet direction. When fluid flow through the valve 20′ is in the inlet-to-outlet direction, the fluid pressure against the check valve plate 34 moves the check valve plate 34 towards a position of engagement against the at least one opening 38 in the retaining plate 36 to substantially prevent fluid flow through the at least one opening 38 in the retaining plate 36 towards the outlet 24.
The check valve plate 34 comprises at least one opening through which fluid may flow when the check valve plate 34 is in a position to permit fluid flow. When fluid flow is in the outlet-to-inlet direction, the second valve element 34 is movable away from the restriction plate 36 and towards opening 32 to permit fluid flow through the passageway 30 to the at least one opening in the restriction plate 36 and the check valve plate 34, through opening 32 to the valve inlet 22. Fluid flowing through the valve 20′ in the outlet-to-inlet direction establishes pressure against the check valve plate 34 to move the check valve plate 34 away from the at least one opening in the restriction plate 36 and towards the second valve opening 32. Thus, in reverse flow situations, the check valve plate 34 is movable away from the restriction plate 36 and towards the opening 32, in which position the check valve plate 34 permits fluid flow from the outlet 24 through the at least one opening 38 in the restriction plate 36 and the opening 32 to the inlet 22.
In a third embodiment 20′′ as shown in FIG. 3, the valve comprises a valve body including an inlet chamber 22, an outlet chamber 24, and a check valve chamber 40 having an opening through the side of the valve body. The valve includes a cover 42 secured within the opening in the side of the valve body leading to the check valve chamber 40. The cover 42 is configured to seal off the check valve chamber 40, and is preferably secured within the valve body side chamber 40 by a means selected from one of a group consisting of an interference press fit, an adhesive, an ultrasonic weld, or a weld.
The third embodiment 20′′ comprises a first valve opening 26 disposed between the inlet chamber 22 and outlet chamber 24, and a control valve element 28 movable relative to the first valve opening 26 to regulate fluid flow from the inlet 22 through the outlet 24 when fluid flow is in the inlet-to-outlet direction. The control valve element 28 is further movable to engage the first valve opening 26 when fluid flow is in the outlet-to-inlet direction to substantially restrict or prevent the fluid flow through the first valve opening to the inlet. Thus, the first valve element 28 does not permit fluid flow from the outlet 24 through the first valve opening 26 to the inlet 22.
The third embodiment further comprises a passageway 30 between the inlet chamber 22 and the check valve chamber 40, where the passageway 30 is entirely disposed within the valve body. A second valve opening 32 is disposed between the check valve chamber 40 and outlet chamber 24. A check valve plate 34 is disposed within the check valve chamber 40, and is movable relative to the second valve opening 32. When fluid flow is in the inlet-to-outlet direction, the check valve plate 34 is movable to restrict fluid flow from the inlet 22 through the second valve opening 32 as shown in FIG. 3. Thus, the check valve plate 34 does not permit fluid flow from the inlet 22 through the second valve opening 32 and passage 30 to the outlet 24.
When fluid flow is in the outlet-to-inlet direction, the check valve plate 34 is movable away from the second valve opening 32 to permit fluid flow from the outlet chamber 24 through the second valve opening 32 around the outer periphery of the check valve plate 34 and through the passage 30 to the inlet 22. The check valve plate 34 may further comprise at least one guide member 44 configured to guide the movement of the check valve plate 34 relative to the second valve opening 32. Thus, in reverse flow situations, the check valve plate 34 is movable away from the second valve opening 32 to permit fluid flow from the outlet 22 through the second valve opening 32 and passage 30 to the inlet 22.
In some embodiments, the cover 42 may further comprise a projection for limiting the movement of the check valve plate 34 away from the second valve opening 32. In alternate embodiments, the guide members 44 on the check valve plate 34 may also limit the movement of the check valve plate 34 relative to the second valve opening 32.
In a fourth embodiment shown in FIG. 4, the valve 20′′′ is substantially the same as the third embodiment, with the exception of the check valve plate 34 and cover 42. In this embodiment, the valve further comprises a retaining plate 36 having at least one opening 38 therein through which fluid may flow. The check valve plate 34 comprises at least one opening through which fluid may pass when the check valve plate is in a position to permit fluid flow through the second valve opening 32. When fluid flow through the valve 20′′′ is in the inlet-to-outlet direction, the fluid pressure against the check valve plate 34 moves the check valve plate 34 against the wall defining the second valve opening 32. In this position, the at least one opening in the check valve plate 34 is against the wall defining the second valve opening 32, such that fluid flow through the at least one opening is substantially restricted. Thus, the check valve plate 34 does not permit fluid flow from the inlet 22 through the passage 30 and second valve opening 32 to the outlet 24.
When fluid flow through the valve 20′′′ is in the outlet-to-inlet direction, pressure against the check valve plate 34 moves the check valve plate 34 away from the second valve opening 32 to permit fluid flow from the outlet 24 through the second valve opening 32 and the at least one opening in the check valve plate 34. Thus, in reverse flow situations, the check valve plate 34 is movable away from the second valve opening 32, in which position the check valve plate 34 permits fluid flow from the outlet 22 through the at least one opening in the retaining plate 36 and the passageway 30 to the inlet 22.
The description of the invention is merely exemplary in nature and, thus, variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention.

## Claims

1. A valve for controlling bidirectional flow of fluid through the valve comprising:
a valve body having an inlet chamber and an outlet chamber, and a recess in the side of the body that includes a passage in communication with the outlet chamber;
a first valve opening disposed between the inlet chamber and outlet chamber;
a second valve opening disposed in the recess in the side of the body, in the flow path between the inlet chamber and the outlet chamber;
a cover that is secured to the valve body and covers the recess to form a side chamber, the cover including a flat surface that is spaced apart from the second valve opening and spans across the opening area of the second valve opening, and a raised portion on the center of the flat surface;
a control valve element movable relative to the first valve opening to regulate fluid flow from the inlet through the outlet when fluid flow is in the inlet-to-outlet direction, the control valve element being movable to sealingly engage the first valve opening when fluid flow is in the outlet-to-inlet direction;
a check valve element movable relative to the second valve opening, the valve element being movable to engage the second valve opening to prevent fluid flow through the second valve opening when fluid flow is in the inlet-to-outlet direction, and movable away from the second valve opening to permit fluid flow through the second valve opening and passage in the recess to the exit when fluid flow is in the outlet-to-inlet direction; wherein the check valve element comprises a plate adapted to sealingly engage the second valve opening, said plate being disposed completely within the recess in the valve body adjacent the second valve opening, wherein the check valve element comprises a plate having at least two spaced apart projections for limiting the movement of the check valve plate away from the second valve opening, the at least two projections extending from the side opposite the sealing surface of the check valve plate, which projections are adapted to engage the flat surface of the cover when the check valve element moves away from the second valve opening, for limiting the plate's movement to thereby retain the check valve plate within the recess adjacent the valve opening, wherein the at least two projections on the check valve plate are positioned relative to the raised portion on the cover so as to be configured to restrict movement of the check valve plate towards the passage in the recess, such that check valve plate is restrained from moving against the passage and restricting fluid flow to through the passage.

2. A valve for controlling bidirectional flow of fluid through the valve comprising:
a valve body having an inlet chamber, an outlet chamber, and a side chamber;
a passageway between the inlet chamber and side chamber, the passageway being entirely disposed within the valve body;
a first valve opening disposed between the inlet chamber and outlet chamber;
a second valve opening disposed between the side chamber and outlet chamber;
a cover that is secured to the valve body for enclosing and sealing off the side chamber, the cover including a flat surface that is spaced apart from the second valve opening and spans across the opening area of the second valve opening, and a raised portion on the center of the fiat surface;
a control valve element movable relative to the first valve opening to regulate fluid flow from the inlet through the outlet when fluid flow is in the inlet-to-outlet direction, the control valve element being movable to sealingly engage the first valve opening when fluid flow is in the outlet-to-inlet direction;
a check valve plate disposed adjacent the second valve opening, wherein the check valve plate is a generally flat plate adapted to sealingly engage the second valve opening, being disposed completely within a recess in the valve body adjacent the second valve opening, wherein the check valve plate comprises a generally flat plate having at least two spaced apart projections for limiting the movement of the check valve plate away from the second valve opening, the at least two projections extending from the side opposite the sealing surface of the check valve plate, which projections are adapted to engage the flat surface of the cover when the check valve element moves away from the second valve opening, for limiting the plate's movement to thereby retain the check valve plate within the recess adjacent the valve opening, the check valve element being movable to restrict fluid flow through the second valve opening when fluid flow is in the inlet-to-outlet direction, and movable away from the second valve opening to permit fluid flow through the second valve opening and passageway to the inlet chamber when fluid flow is in the outlet-to-inlet direction; wherein the at least two projections on the check valve plate are positioned relative to the raised portion on the cover so as to be configured to restrict movement of the check valve plate towards the passage in the recess, such that check valve plate is restrained from moving against the passage and restricting fluid flow to through the passage.

3. A valve for controlling bidirectional flow of fluid through the valve comprising:
a valve body including an inlet chamber, an outlet chamber, and a check valve chamber having an opening through the side of the valve body;
a first valve opening disposed between the inlet chamber and outlet chamber;
a control valve element movable relative to the first valve opening to regulate fluid flow from the inlet through the outlet when fluid flow is in the inlet-to outlet direction, the control valve element being movable to sealingly engage the first valve opening when fluid flow is in the outlet-to-inlet direction;
a passageway between the inlet chamber and check valve chamber, the passageway being entirely disposed within the valve body;
a second valve opening disposed between the check valve chamber and outlet chamber;
a cover that is secured to the valve body for enclosing and sealing off the side chamber, the cover including a flat surface that is spaced apart from the second valve opening and spans across the opening area of the second valve opening, and a raised portion on the center of the flat surface;
a check valve plate movable relative to the second valve opening, wherein the check valve plate is a generally flat plate adapted to sealingly engage the second valve opening, being disposed completely within a recess in the check valve chamber adjacent the second valve opening, wherein the check valve plate comprises a generally flat plate having at least two spaced apart projections for limiting the movement of the check valve plate away from the second valve opening, the at least two projections extending from the side opposite the sealing surface of the check valve plate, which projections are adapted to engage the flat surface of the cover when the check valve element moves away from the second valve opening, for limiting the plate's movement to thereby retain the check valve plate within the recess adjacent the valve opening, the check valve plate being movable to restrict fluid flow from the inlet through the second valve opening when fluid flow is in the inlet-to-outlet direction, and movable away from the second valve opening to permit fluid flow from the outlet chamber through the second valve opening and passageway when fluid flow is in the outlet-to-inlet direction; wherein the at least two projections on the check valve plate are positioned relative to the raised portion on the cover so as to be configured to restrict movement of the check valve plate towards the passage in the recess, such that check valve plate is restrained from moving against the passage and restricting fluid flow to through the passage.