US20190323748A1

US20190323748A1 - Insert for a thermostatic expansion valve, thermostatic expansion valve and method for assembling a thermostatic expansion valve

Info

Publication number: US20190323748A1
Application number: US16/099,564
Authority: US
Inventors: Ole Mortensen; Erik Thomas Bonde; Jens Erik Rasmussen
Original assignee: Danfoss AS
Current assignee: Danfoss AS
Priority date: 2016-05-11
Filing date: 2017-05-11
Publication date: 2019-10-24
Also published as: WO2017194651A1; CN109073294A; EP3455565A1; CN113048250A

Abstract

The invention relates to an insert (1) for a thermostatic expansion valve as a thermostatic expansion valve (2) comprising such an insert and to a method of assembling such a thermostatic expansion valve (2). The insert (1) comprises an expansion valve element (3) and an expansion valve seat (4). The expansion valve element (3) is held inside the insert (1) by a biasing member (5), wherein the insert (1) is structured and arranged to be inserted into a valve housing (8). The task of the invention is to provide an insert for a thermostatic expansion valve that allows a simple assembly of the valve and also provides an improved functionality. The task is solved in that the insert (1) further comprises a control valve (12), wherein the control valve (12) is located in the same flow path through the insert (1) as the expansion valve seat (4).

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a National Stage application of International Patent Application No. PCT/EP2017/061274, filed on May 11, 2017, which claims priority to Denmark Patent Application No. PA201600288, filed on May 11, 2016, each of which is hereby incorporated by reference in its entirety.

TECHNICAL FILED

The invention relates to an insert for a thermostatic expansion valve comprising an expansion valve element and an expansion valve seat, wherein the expansion valve element is held inside the insert by a biasing member, wherein the insert is structured and arranged to be inserted into a valve housing. The invention further relates to a thermostatic expansion valve comprising an insert of the above kind as well as to a method for assembling a thermostatic expansion valve.

BACKGROUND

Thermostatic expansion valves regulate the flow of a refrigerant in a cooling or heating system, for example air conditioning systems. Such thermostatic expansion valves often comprise a diaphragm separating pressure chambers. One of the pressure chambers is, for example, connected to a temperature sensing bulb via a capillary tube, see e.g. JPS 6 241 481 A, or for example a rod, see e.g. U.S. Pat. No. 6,375,085 B1. In both cases the temperature of the refrigerant coming from the evaporator can be probed to automatically readjust the position of the expansion valve element relative to the expansion valve seat to increase or decrease the flow of refrigerant towards the evaporator.
To simplify the assembly it is furthermore known to combine the expansion valve element and the expansion valve seat in an insert that can be connected to the valve housing. An actuator connected to the diaphragm can then engage the expansion valve element arranged in the insert. Such a system is, for example, shown for comparison in FIGS. 1A and 1B. However, the functionality of such a thermostatic expansion valve is limited since there is no direct control of the refrigerant flow possible without an additional control valve arranged in the cooling or heating system. Consequently, it is known to use an additional solenoid valve to influence the pressure in the pressure chambers of the capsule as, for example known, from JPS 6 241 481 A. Alternatively, the additional solenoid valve can be used in a flow control valve placed upstream of the thermal expansion valve seat as known, for example, from U.S. Pat. No. 6,375,085 B1.
Both solutions are however relatively complicated to assemble since the thermostatic expansion valve element and a corresponding biasing member, as well as the solenoid valve and intermediately arranged main and pilot valve elements need to be inserted and connected to the valve housing one after another.

SUMMARY

The task of the present invention is therefore to provide an insert for a thermostatic expansion valve that allows a simplified assembly.
The above task is solved in an insert of the kind mentioned in the outset in that the insert further comprises a control valve, wherein the control valve is located in the same main flow path through the insert as the expansion valve seat.
With the above solution the assembly is simplified since both the control valve as well as the expansion valve element and the expansion valve seat are arranged in the same insert to be installed in a valve housing. The insert can then be inserted and connected to the valve housing with a reduced number of assembly steps. At the same time the thermal expansion valve has an improved functionality over simple inserts as shown in FIGS. 1a and 1 b. In particular, the insert now also includes a control valve which allows to directly regulate the flow of refrigerant through the cooling or heating system.
It is preferred if the control valve comprises a solenoid valve. The solenoid valve may either be a main valve or a part of a piloted valve.
Preferably, the control valve further comprises a main valve, wherein the solenoid valve is a pilot valve controlling the opening and closing of the main valve. Preferably, the pilot valve element and the main valve element are arranged adjacent to one another. In this case, the pilot valve seat may be arranged in the main valve element.
It is preferred if the control valve is located upstream of the expansion valve seat in the main flow path. The control valve ensures that no liquid passes the expansion valve, for example during a compressor standstill, by closing the control valve. In this case the control valve will usually be located between the condenser and the expansion valve when the insert is installed into the thermostatic expansion valve used in a refrigeration system.
It is preferred if the insert comprises an insert inlet from which the main flow path leads to the control valve.
It is furthermore preferred if the main flow path continues from the control valve to the expansion valve seat, wherein the expansion valve seat also forms the insert outlet.
It is preferred if the expansion valve element comprises an engagement surface that is arranged to be engaged by an actuator that is external to the insert. The engagement surface can, for example, be a flat surface to be engaged by a pin or a stem of an actuator of the expansion valve. When the insert is introduced and connected to an expansion valve housing the engagement surface will then be brought into engagement with an actuator arranged in the valve housing of the thermostatic expansion valve.
The above task is also solved by a thermostatic expansion valve comprising an insert according to any of the preceding embodiments, as well as a valve housing, wherein the valve housing comprises a valve inlet and a valve outlet. In this case the main flow path through the thermostatic expansion valve can start from the valve inlet lead to the insert inlet, through the control valve, to the expansion valve seat and the insert outlet and then towards the valve outlet.
It is preferred if the thermostatic expansion valve further comprises an expansion valve actuator to engage the expansion valve element. The expansion valve actuator is preferably connected to the valve housing.
In a preferred embodiment the expansion valve actuator comprises a stem to engage the engagement surface of the expansion valve element. When the insert is introduced into the valve housing the stem is then brought into engagement with the engagement surface of the expansion valve element and then the insert is fixed to the valve housing.
It is preferred if the actuator comprises two pressure chambers separated by a diaphragm, wherein a first pressure chamber is connected to a pressure port of the valve housing and a second pressure chamber is connected to a temperature sensing bulb. This way, one may adjust the pressure in the first pressure chamber to control the opening behavior of the expansion valve beyond a simple control via the temperature sensing bulb which responds to the state of the refrigerant in the system, preferably after the refrigerant has exited the evaporator.
The above task is also solved by a method for assembling a thermostatic expansion valve comprising the following steps:

- Providing a valve housing comprising a valve inlet, a valve outlet as well as an expansion valve actuator,
- Providing an insert according to any of claims 1 to 7,
- Inserting the insert into a predetermined opening of the valve housing, such that the expansion valve actuator comes into engagement with the expansion valve element in the insert,
- Fixing the insert to the valve housing.

With this solution the assembly of a thermostatic expansion valve comprising a control valve is particularly simple. It is no longer necessary to introduce the individual elements of the expansion valve and the control valve one after another into the valve housing or to install the control valve and the expansion valve separately. On the contrary, it is now possible to use a single connection step to connect the insert comprising the expansion valve element and the expansion valve seat as well as the control valve to the valve housing.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the invention will now be described with reference to the Figures, wherein:

FIG. 1A shows a thermostatic expansion valve according to the state of the art,

FIG. 1B shows an insert as used in the thermostatic expansion valve according to FIG. 1A,

FIG. 2 shows an insert according to the invention with closed main and pilot valves,

FIG. 3 shows a thermostatic expansion valve comprising an insert according to FIG. 2 with a closed main and pilot valve,

FIG. 4 shows a detail of a thermostatic expansion valve according to FIG. 3,

FIG. 5 +6 show the thermostatic expansion valve according to FIGS. 3 and 4 with open main and pilot valves.

DETAILED DESCRIPTION

FIG. 1A and 1B show for comparison the state of the art of an insert 101 as well as a thermostatic expansion valve 102 comprising such an insert 101. The insert 101 comprises an expansion valve element 103 as well as an expansion valve seat 104. The expansion valve element 103 is biased by a biasing member 105 against the expansion valve seat 104, in this case a spring. The insert 101 furthermore comprises an insert inlet 106 as well as an insert outlet 107. The expansion valve seat 104 is in this embodiment arranged at the insert outlet 107. At the insert inlet 106 a strainer 131 is arranged.
The thermostatic expansion valve 102 furthermore comprises a valve housing 108 in which a valve inlet 109 as well as a valve outlet 110 is arranged.
The thermostatic expansion valve 102 also comprises an actuator 111 to actuate the expansion valve element 103. The insert 101 furthermore comprises a strainer 131 arranged near the insert inlet 106.
FIGS. 2 to 6 show the same preferred embodiment of the invention, where FIGS. 2 to 4 show the insert and the expansion valve comprising the insert with a closed control valve while FIGS. 5 and 6 show the same embodiment with an open control valve. Corresponding features will be denoted with the same reference signs.
According to the invention the insert 1 to be inserted into a thermostatic expansion valve 2 comprises an expansion valve element 3 as well as an expansion valve seat 4. The expansion valve element 3 is biased against the expansion valve seat 4 by a biasing member 5.
The insert 1 further comprises an insert inlet 6 as well as an insert outlet 7. The insert outlet 7 here is arranged in the same opening in which the expansion valve seat 4 is arranged. At the insert inlet 6 a strainer 31 is arranged.
In FIGS. 3 to 5 the insert 1 is arranged in a thermostatic expansion valve 2 comprising a valve housing 8. The valve housing 8 comprises a valve inlet 9 as well as a valve outlet 10. Fluid coming from the valve inlet 9 flows to the insert inlet 6 towards a control valve 12. The control valve 12 comprises a solenoid valve 13, which in this case acts as a pilot valve. The solenoid valve 13 comprises a coil 14, an anchor core 15 as well as an armature 16. The armature 16 is connected to a pilot valve element 17 which in all FIGS. 2 to 6 engages a pilot valve seat 18. The control valve 12 furthermore comprises a main valve, comprising a main valve element 19 as well as a main valve seat 20. The pilot valve seat 18 is arranged on one end of a channel leading through the main valve element 19. A servo piston 32 is arranged coaxially around the main valve element 19.
When the solenoid valve 13 is activated the armature 16 as well as the pilot valve element 17 will be moved downwards and away from the main valve element 19. Thereby a fluid path through the main valve element 19 is opened. Furthermore, a pressure difference is created across the top and bottom side of the servo piston 32. This results in a pressure force that moves the servo piston 32 towards the solenoid valve 13 until the servo piston 32 abuts the main valve element 19 and pulls the main valve element 19 also towards the solenoid valve 13. Thereby, the main valve of the control valve 12 is opened. This situation can be seen in FIGS. 5 and 6.
If the expansion valve element 3 does not engage the expansion valve seat 4 the fluid can then flow through the expansion valve towards the valve outlet 10 and, for example, towards an external evaporator.
The thermostatic expansion valve 2 furthermore comprises an actuator 11, which in this case takes the form of a capsule. The actuator 11 comprises a diaphragm 22 which is at its radial outer ends fixed to the valve housing 8. The diaphragm 22 separates a first pressure chamber 23 from a second pressure chamber 24. The first pressure chamber 23 is connected to a pressure port 25 which allows to change the pressure in the first pressure chamber 23 to adjust the opening behavior of the thermostatic expansion valve 2.
The second pressure chamber 24 is connected to a temperature sensing bulb 26. The temperature sensing bulb 26 can be connected, for example, to an outlet of an external evaporator to readjust the opening degree of the thermostatic expansion valve 2 according to the state of the refrigerant exiting the evaporator.
The actuator 11 furthermore comprises a spring 27 which acts as a biasing member inside the first pressure chamber 23. The diaphragm 22 is connected both to the spring 27 as well as to a stem 28. The stem 28 engages the expansion valve element 3 at an engagement surface 29.
When the insert 1 is introduced into the valve housing 8 the expansion valve element 3 is brought into contact with the actuator 11, in particular at the end of the stem 28. At the same time the insert 1 is fixed to the valve housing 8 by a connection geometry 30, for example a screw connection.
The insert 1 according to the invention consequently allows to assemble a thermostatic expansion valve 2 in a simplified manner while still providing the functionality of a thermostatic expansion valve as well as of a control valve 12 which provides a direct control of the flow through the thermostatic expansion valve 2. Moreover, the invention also provides a simplified method of assembly of a thermostatic expansion valve.
While the present disclosure has been illustrated and described with respect to a particular embodiment thereof, it should be appreciated by those of ordinary skill in the art that various modifications to this disclosure may be made without departing from the spirit and scope of the present disclosure.

Claims

What is claimed is:

1. An insert for a thermostatic expansion valve comprising an expansion valve element and an expansion valve seat, wherein the expansion valve element is held inside the insert by a biasing member, wherein the insert is structured and arranged to be inserted into a valve housing, wherein the insert further comprises a control valve, wherein the control valve is located in the same main flow path through the insert as the expansion valve seat.

2. The insert according to claim 1, wherein the control valve comprises a solenoid valve.

3. The insert according to claim 2, wherein the control valve further comprises a main valve, wherein the solenoid valve is a pilot valve controlling the opening and closing of the main valve.

4. The insert according to claim 1, wherein the control valve is located upstream of the expansion valve seat in the main flow path.

5. The insert according to claim 4, wherein the insert comprises an insert inlet from which the main flow path leads to the control valve.

6. The insert according to claim 5, wherein the main flow path continues from the control valve to the expansion valve seat, wherein the expansion valve seat also forms an insert outlet.

7. The insert according to claim 1, wherein the expansion valve element 3 comprises an engagement surface that is arranged to be engaged by an actuator that is external to the insert.

8. A thermostatic expansion valve comprising an insert according to claim 1, as well as a valve housing, wherein the valve housing comprises a valve inlet and a valve outlet.

9. The thermostatic expansion valve according to claim 8, wherein the thermostatic expansion valve further comprises an actuator to engage the expansion valve element.

10. The thermostatic expansion valve according to claim 9, wherein the actuator comprises a stem to engage the engagement surface of the expansion valve element.

11. The thermostatic expansion valve according to claim 8, wherein the actuator comprises two pressure chambers separated by a diaphragm, wherein a first pressure chamber is connected to a pressure port of the valve housing and a second pressure chamber is connected to a temperature sensing bulb.

12. A method for assembling a thermostatic expansion valve comprising the steps:

Providing a valve housing comprising a valve inlet, a valve outlet as well as an actuator,

Providing an insert according to claim 1,

Inserting the insert into a predetermined opening of the valve housing, such that the actuator comes into engagement with the expansion valve element in the insert,

Fixing the insert to the valve housing.

13. The insert according to claim 2, wherein the control valve is located upstream of the expansion valve seat in the main flow path.

14. The insert according to claim 3, wherein the control valve is located upstream of the expansion valve seat in the main flow path.

15. The insert according to claim 2, wherein the expansion valve element 3 comprises an engagement surface that is arranged to be engaged by an actuator that is external to the insert.

16. The insert according to claim 3, wherein the expansion valve element 3 comprises an engagement surface that is arranged to be engaged by an actuator that is external to the insert.

17. The insert according to claim 4, wherein the expansion valve element 3 comprises an engagement surface that is arranged to be engaged by an actuator that is external to the insert.

18. The insert according to claim 5, wherein the expansion valve element 3 comprises an engagement surface that is arranged to be engaged by an actuator that is external to the insert.

19. The insert according to claim 6, wherein the expansion valve element 3 comprises an engagement surface that is arranged to be engaged by an actuator that is external to the insert.

20. The thermostatic expansion valve comprising an insert according to claim 2, as well as a valve housing, wherein the valve housing comprises a valve inlet and a valve outlet.