Thermostatic expansion valve with bypass passage

• US 7,707,844 B2
• Filed: 02/17/2006
• Issued: 05/04/2010
• Est. Priority Date: 02/17/2006
• Status: Active Grant

• Current Assignee: Emerson Electric Company
• Original Assignee: Emerson Electric Company
• Inventors: Noble, Mike, Nestler, David B.
• Primary Examiner(s): Jules; Frantz F
• Assistant Examiner(s): AZIM, ABDUR RAHIM
• Application Number:
  US11/357,632
• Publication Number:
  US 20070194140A1
• Time in Patent Office: 1,537 Days
• Field of Search: 236/92.B, 622/22, 622/25
• US Class Current: 62/222
• CPC Class Codes: F25B 2500/06 Damage
• CPC Class Codes: F25B 41/325 having two or more valve members
• CPC Class Codes: F25B 41/335 via diaphragms

Abstract

A thermostatic expansion valve is provided comprising an inlet, an outlet, first and second flow paths through the valve, a first valve element in the first flow path between the inlet and outlet, and a movable diaphragm having a first side acted on by a first fluid pressure and a second side acted on by at least a second fluid pressure. The diaphragm is movable to permit increased flow through the first flow path when the force against the first side is greater than that against the second side, and is movable to restrict flow through the first flow path when the force against the first side is less than that against the second side. The diaphragm moves in an upward direction to cause the first valve element to close the first flow path, and may continue to move in the upward direction to cause a second flow path to open.

Claims

1. A thermostatic expansion valve for controlling fluid flow comprising:

an inlet, an outlet, and a first valve element disposed within a first valve opening between the inlet and outlet;

a movable diaphragm having a first side in communication with a pressurized fluid external to the thermostatic expansion valve and a second side in communication with the outlet, the diaphragm being movable relative to a neutral position in response to changes in pressure between the outlet fluid pressure and the external fluid pressure, wherein the movement of the diaphragm controls the first valve element to regulate the fluid flow rate through the valve; and

a second valve element disposed within a second valve opening between the inlet and the outlet, wherein the second valve element is coupled with the diaphragm, such that the second valve element is configured to be moved by the diaphragm away from the second valve opening for permitting fluid flow from the inlet through the second valve opening and a bypass passageway to the outlet;

wherein the diaphragm is configured to respond to a force against the first side of the diaphragm that is less than the force against the second side by moving the first valve element to a closed position against the first valve opening and moving the second valve element away from the second valve opening so as to restrict fluid flow through the first valve opening to the outlet and permit fluid flow through the second valve opening to the outlet.

2. The thermostatic expansion valve of claim 1 further comprising an actuator member for engaging the movable diaphragm and the first valve element to permit the movement of the diaphragm to control the movement of the first valve element to regulate the fluid flow through the valve.

3. The thermostatic expansion valve of claim 2 further comprising a spring for biasing the first valve element towards a closed position, wherein the spring biasing force is applied to the second side of the diaphragm while the first valve element is open.

4. The thermostatic expansion valve of claim 3 wherein the diaphragm is movable to increase fluid flow through the valve when the force against the first side of the diaphragm is greater than against the second side, and to restrict fluid flow through the valve when the force against the first side is less than against the second side.

5. The thermostatic expansion valve of claim 1 wherein the second valve element comprises a pin that is slidable relative to the second valve opening that is in communication with a bypass passageway, and is biased by a second spring against the second valve opening that is in communication with the bypass passageway, wherein the diaphragm allows the pin to move away from the second valve opening that is in communication with the bypass passageway when the diaphragm is displaced upwardly by more than a predetermined amount beyond the point of closure of the first valve element.

6. A thermostatic expansion valve for controlling fluid flow comprising:

an inlet, an outlet, and a first valve element disposed within a first valve opening between the inlet and outlet;

a movable diaphragm for controlling the first valve element, the diaphragm having a first side acted on by a first fluid pressure and a second side acted on by at least a second fluid pressure, the diaphragm being movable to position the first valve element to increase fluid flow through the valve first valve opening when the force against the first side is greater than that against the second side and to move the first valve element towards a closed position against the first valve element to restrict fluid flow through the first valve opening when the force against the first side is less than that against the second side; and

a second valve element disposed within a second valve opening between the inlet and the outlet, wherein the second valve element is in connection with the diaphragm, the second valve element being configured to be moved by the diaphragm away from the second valve opening to permit fluid flow through the second valve opening and a bypass passage to the outlet,

wherein the diaphragm is configured to respond to a force against the first side of the diaphragm is less than the force against the second side by moving the first valve element to a closed position against the first valve opening and moving the second valve element away from the second valve opening so as to restrict fluid flow through the first valve opening to the outlet and permit fluid flow through the second valve opening to the outlet.

7. The thermostatic expansion valve of claim 6 further comprising an actuator member for engaging the movable diaphragm and the first valve element to permit the movement of the diaphragm to control the movement of the first valve element to regulate the fluid flow through the valve.

8. The thermostatic expansion valve of claim 7 further comprising a spring for biasing the first valve element towards a closed position, wherein the spring biasing force is applied to the second side of the diaphragm while the first valve element is open.

9. The thermostatic expansion valve of claim 6 wherein the second side of the diaphragm is acted on by both a second fluid pressure and a spring force.

10. The thermostatic expansion valve of claim 6 wherein the second valve element comprises a pin that is slidable relative to the second valve opening that is in communication with a bypass passageway, and is biased by a second spring against the second valve opening that is in communication with the bypass passageway, wherein the diaphragm allows the pin to move away from the second valve opening that is in communication with the bypass passageway when the diaphragm is displaced upwardly by more than a predetermined amount beyond the point of closure of the first valve element.

11. A thermostatic expansion valve for controlling fluid flow and a bypass passage to the outlet comprising:

an inlet, an outlet, and a first valve element disposed within a first valve opening between the inlet and outlet;

a movable diaphragm having a first side in communication with a fluid pressure source external to the thermostatic expansion valve and a second side in communication with the outlet, the diaphragm being movable relative to a neutral position in response to changes in the pressures against the first and second sides of the diaphragm for regulating fluid flow through the first valve opening, wherein the diaphragm is movable to position the first valve element to permit increased fluid flow through the first valve opening when the force against the first side is greater than that against the second side, and is movable to move the first valve element towards a closed position against the first valve element to restrict fluid flow through the first valve opening when the force against the first side is less than that against the second side;

a spring for biasing the first valve element towards a closed position; and

a second valve element disposed within a second valve opening between the inlet and the outlet, wherein the second valve element is engagable by the diaphragm such that the second valve element is configured to be moved away from the second valve opening by the diaphragm to permit fluid flow through the second valve opening;

wherein the diaphragm is configured to respond to a force against the first side of the diaphragm that is less than the force against the second side by moving the first valve element to a closed position against the first valve opening and moving the second valve element away from the second valve opening so as to restrict fluid flow through the first valve opening to the outlet and permit fluid flow through the second valve opening to the outlet.

12. The thermostatic expansion valve of claim 11 further comprising an actuator member for engaging the movable diaphragm and the first valve element to permit the movement of the diaphragm to control the movement of the first valve element to regulate the fluid flow through the valve.

13. The thermostatic expansion valve of claim 12 wherein the spring biasing force is further applied to the second side of the diaphragm through the actuator member.

14. The thermostatic expansion valve of claim 11 wherein the second side of the diaphragm is acted on by a second fluid pressure and a spring force.

15. The thermostatic expansion valve of claim 11 wherein the second valve element comprises a pin that is slidable relative to the second valve opening that is in communication with a bypass passageway, and is biased by a second spring against the second valve opening that is in communication with the bypass passageway, wherein the diaphragm allows the pin to move away from the second valve opening that is in communication with the bypass passageway when the diaphragm is displaced upwardly by more than a predetermined amount beyond the point of closure of the first valve element.

16. A thermostatic expansion valve for controlling fluid flow comprising:

an inlet, an outlet, a first valve seat between the inlet and outlet defining a first flow path, and a second valve seat between the inlet and the outlet defining a second flow path in parallel with the first flow path;

a first valve member movable relative to the first valve seat between the inlet and outlet;

a spring for biasing the first valve member towards a closed position against the first valve seat;

a movable diaphragm having a first side acted on by a first fluid pressure and a second side acted on by at least a second fluid pressure, the diaphragm being movable relative to a neutral position in response to changes in the forces against the first and second sides of the diaphragm to control the position of the first valve member for regulating the fluid flow through the first valve seat, wherein the diaphragm is movable to position the first valve member to permit increased fluid flow through the first valve seat when the force against the first side is greater than that against the second side, and is movable to move the first valve member towards the closed position against the first valve seat to restrict fluid flow through the first valve seat when the force against the first side is less than that against the second side; and

a second valve member that is normally closed against the second valve seat, the second valve member having a surface that is engagable by the diaphragm, such that the second valve member is configured to be moved by the diaphragm away from the second valve seat to permit fluid flow through the second valve seat and a bypass passage to the outlet;

wherein the diaphragm is configured to respond to a force against the first side of the diaphragm that is less than the force against the second side by moving the first valve member to a closed position against the first valve seat and moving the second valve member to an open position away from the second valve seat, such that the first valve member restricts fluid flow through the first valve opening defining the first flow path to the outlet, and the second valve member permits fluid flow through the second valve opening defining the second flow path to the outlet.

17. The thermostatic expansion valve of claim 16 wherein the second valve member is engaged by a buffer member that is moved upwardly when the diaphragm moves in an upward direction more than a predetermined distance beyond the point of closure of the first valve member against the first valve seat.

18. The thermostatic expansion valve of claim 17 further comprising a spring for biasing the second valve member to a normally closed position against the second valve seat, which biasing force is removed when the buffer member engages the surface on the second valve member to cause the second valve member to move to an open position relative to the second valve seat.

19. The thermostatic expansion valve of claim 16 wherein the first fluid pressure acting on the first side of the diaphragm is provided by a capillary tube external to the thermostatic expansion valve, and the diaphragm moves in an upward direction to engage the surface on the second valve member for moving the second valve member to an open position when there is a loss of pressure acting against the first side of the diaphragm.