Dual-orifice expansion valve

Abstract

The present disclosure relates to a dual orifice expansion valve comprising a first orifice and a second orifice and comprising: a housing; a movable first valve element arranged within the housing and movable relative to the housing to vary the opening of the first orifice; a movable second valve element arranged within the first valve element and movable relative to the first valve element to vary the opening of the second orifice; and an actuator, wherein the housing is provided with a first guide portion, an outer surface of the first valve element is in slidable contact with the first guide portion such that movement of the first valve element is guided by the first guide portion; and the first valve element is provided with a second guide portion, an outer surface of the second valve element is in slidable contact with the second guide portion such that movement of the second valve element is guided by the second guide portion.

Description

Technical Field

[0001] This disclosure relates to an expansion valve, and more particularly to a two-orifice expansion valve for use in refrigeration systems. Background Technology

[0002] An expansion valve is a crucial component in a refrigeration system. Located between the condenser and evaporator, it throttles and reduces the pressure of the high-pressure liquid refrigerant exiting the condenser to the evaporation pressure. It also adjusts the amount of liquid refrigerant entering the evaporator based on system load changes. The basic principle of an expansion valve is to force the high-pressure liquid refrigerant through a small throttling area, creating appropriate local resistance losses and causing a rapid drop in refrigerant pressure. Simultaneously, some of the liquid refrigerant vaporizes, absorbing latent heat, resulting in a low-pressure, low-temperature refrigerant after throttling.

[0003] In a refrigeration cycle, the capacity under each condition is determined by the compressor. Due to the vapor compression characteristics of a constant-capacity compressor, the mass flow decreases as the pressure differential increases. However, for the expansion valve, the mass flow increases with increasing pressure differential. As a result, under high pressure differentials, only a small opening of the expansion valve is needed, while under low pressure differentials, a large opening is required to ensure a higher mass flow.

[0004] Traditional expansion valves consist of a valve seat with an orifice and a valve core movable relative to the valve seat. The valve core typically includes a conical valve head inserted into the orifice. An actuator drives the valve core, thereby adjusting the degree to which the valve head is inserted into the orifice according to the pressure differential, thus regulating the opening or throttling area of ​​the expansion valve. The force applied by the actuator to the valve core to move it is limited by the orifice size and the maximum pressure differential requirement. For an expansion valve with a maximum pressure differential requirement of 3 MPa and a maximum orifice opening of 3.5 mm diameter, the actuator needs to provide a force of 29 N based on the maximum value. However, in reality, for a pressure differential of 3 MPa, since the actual orifice opening is only 2.5 mm diameter, the required force is only 15 N. Nevertheless, to ensure that the expansion valve can operate at both the high and low pressure differentials, the actuator is usually designed based on the maximum value, requiring it to provide at least 29 N of force, which increases the cost.

[0005] In the prior art, a dual-orifice expansion valve has been proposed. This valve is equipped with a small valve needle and a large valve needle to open the small and large valve ports respectively. However, this expansion valve is a balanced valve type, with a flow passage in the small valve needle. When the pressure difference between the inlet and outlet sides is large, pressure is released through the flow passage to achieve pressure balance between the inlet and outlet sides. This ensures the driving torque while enabling the miniaturization of the valve body structure. This balanced expansion valve has a complex structure and requires additional sealing structures to prevent leakage. Summary of the Invention

[0006] To overcome the problems in existing technologies, a dual-orifice expansion valve is provided, in which two concentric orifices are operated by the same actuator. Under high pressure differential, only the inner orifice is opened, allowing for fine control of the throttling area. Under low pressure differential, both the inner and outer orifices are opened, increasing the throttling area and thus meeting the high flow rate requirements under low pressure differential. This allows the actuator to be designed to apply a smaller force while simultaneously meeting the requirements for both low pressure differential at small openings and high pressure differential at large openings. Furthermore, the smaller inner orifice significantly improves flow control accuracy under high pressure differential and small opening conditions.

[0007] According to one aspect of this disclosure, a dual-orifice expansion valve is provided, the dual-orifice expansion valve including a first orifice and a second orifice, and operating under a first pressure differential with a flow path through only the second orifice, and under a second pressure differential with a flow path through both the first orifice and the second orifice, the dual-orifice expansion valve comprising: a housing including a fluid inlet, a fluid outlet, and the first orifice in a flow path from the fluid inlet to the fluid outlet; a movable first valve element disposed within the housing and movable relative to the housing to change the opening degree of the first orifice, wherein the first valve element is provided with a second orifice in the fluid path; and a movable second valve element disposed within the housing. The housing is provided with a first valve element and is movable relative to the first valve element to change the opening degree of the second orifice; and an actuator that causes the second valve element to move relative to the first valve element between a first position and a second position, wherein in the first position the second orifice has a first opening degree, and in the second position the second orifice has a second opening degree different from the first opening degree, wherein the housing is provided with a first guide portion, the outer surface of the first valve element is slidably in contact with the first guide portion such that the movement of the first valve element is guided by the first guide portion; and the first valve element is provided with a second guide portion, the outer surface of the second valve element is slidably in contact with the second guide portion such that the movement of the second valve element is guided by the second guide portion.

[0008] Therefore, under a typically large first pressure differential, since the expansion valve operates only through the second orifice, the force required by the actuator only needs to consider the first pressure differential and the effective area of ​​the second valve element that changes the opening of the second orifice. This reduces the force required by the actuator, allowing for the selection of a smaller actuator. Under a typically smaller second pressure differential, both the first and second orifices are fully open, thus satisfying the requirement for a large mass flow under a small pressure differential.

[0009] Furthermore, in the expansion valve according to this disclosure, the movable first valve element is directly guided by the first guide portion of the housing, while the movable second valve element is guided by the second guide portion disposed on the first valve element, thus simplifying the guiding structure.

[0010] In one embodiment, the first valve element is generally a hollow cylindrical shape, its outer peripheral surface is guided by the first guide portion and has an axial direction, wherein the ratio of the length of the first guide portion along the axial direction to the outer diameter of the first valve element is greater than 1.0, and preferably greater than 1.3.

[0011] In one embodiment, the second valve element includes a cylindrical body portion and a tapered valve head portion, the outer peripheral surface of which is guided by a second guide portion, wherein the ratio of the length of the second guide portion along the axial direction to the outer diameter of the cylindrical body portion of the second valve element is greater than 1.0, and preferably greater than 1.3.

[0012] By setting the lengths of the first and second guide portions to be greater than the diameter of the first or second valve element being guided, the accuracy and stability of guiding the first and second valve elements are improved.

[0013] In one embodiment, the housing is further provided with a channel that connects the fluid inlet to the upper side of the first valve element to press the first valve element against the first orifice to close the first orifice.

[0014] By providing a channel in the housing, the pressure from the fluid inlet is directed to the upper side of the first valve element, thereby using the pressure from the fluid inlet to press the first valve element onto the first orifice. This eliminates the need for a biased first valve element, simplifies the structure, and reduces costs.

[0015] In one embodiment, the first valve element has a flange on its inner surface, and the second valve element has a shoulder on its outer surface. When the second valve element is moved to the second position by the actuator, the shoulder abuts against the flange. At the second position where the shoulder abuts against the flange, further movement of the second valve element by the actuator causes the first valve element to move and open the first orifice.

[0016] By providing a flange on the first valve element and a shoulder on the second valve element, the actuation of the first valve element is accomplished by means of the second valve element, and the control of the two valve elements is achieved using a single actuator, simplifying the overall structure.

[0017] In one embodiment, the actuator is connected to the second valve element via a floating connection structure. For example, the floating connection structure includes a groove formed on the outer surface of the second valve element and a clip connected to the actuator, the clip engaging the groove in a state with radial clearance.

[0018] By providing a floating connection between the actuator and the second valve element, and especially by including radial clearance in the floating connection between the actuator and the second valve element, interference between the constraint of the second valve element by the second guide portion and the constraint by the actuator connection structure can be prevented.

[0019] In one embodiment, the housing includes an upper tube and a lower housing, the actuator is disposed in the upper tube, and the first guide portion is formed on the lower housing.

[0020] According to another aspect of this disclosure, a refrigeration system is provided, for example, a refrigeration system for electric vehicles, such as a refrigeration system for cooling the power battery of an electric vehicle, the refrigeration system including at least one dual-orifice expansion valve as described above.

[0021] The foregoing description is illustrative only and is not intended to be limiting in any way. Other aspects, embodiments, and features of the invention will become apparent from the accompanying drawings and the following detailed description, in addition to the illustrative aspects, embodiments, and features described above. Attached Figure Description

[0022] The above and other features, advantages and technical superiority of this disclosure can be understood from the following detailed description of preferred embodiments of this disclosure with reference to the accompanying drawings, in which:

[0023] Figure 1 This is an overall cross-sectional view of a dual-orifice expansion valve according to the present disclosure, wherein the expansion valve is inserted into a valve block for connection to a refrigeration system;

[0024] Figure 2 It is shown Figure 1 The partial cross-sectional view of the dual-orifice expansion valve shown illustrates the structure of the lower housing portion;

[0025] Figure 3 It is shown in Figure 1 The diagram shows a partial enlarged view of the positional relationship between the flange of the first valve element and the shoulder of the second valve element in the indicated state.

[0026] Figure 4 It is shown Figure 1 Another cross-sectional view of the dual-orifice expansion valve shown, wherein the second orifice is in the open state and the first orifice is in the closed state;

[0027] Figure 5 It is shown in Figure 4 A partially enlarged view of the positional relationship between the flange of the first valve element and the shoulder of the second valve element in the state shown.

[0028] Figure 6 It is shown Figure 1 Another cross-sectional view of the dual-orifice expansion valve shown, in which the second valve element is in the second position, the second orifice is at its maximum opening, while the first orifice remains closed;

[0029] Figure 7 It is shown in Figure 6 The diagram shows a partial enlarged view of the positional relationship between the flange of the first valve element and the shoulder of the second valve element in the indicated state.

[0030] Figure 8 It is shown Figure 1 Another cross-sectional view of the dual-orifice expansion valve shown, wherein both the first and second orifices are in the open state; and

[0031] Figure 9 It is shown in Figure 8 The diagram shows a partial enlarged view of the positional relationship between the flange of the first valve element and the shoulder of the second valve element in the indicated state. Detailed Implementation

[0032] Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that this description is for illustrative purposes only and is not intended to be limiting, and those skilled in the art will understand that the invention can be implemented in various ways and should not be limited to the preferred embodiments described herein.

[0033] As used in this invention, the use of "an embodiment" or "this embodiment" does not mean that the features described in one embodiment of the invention can only be used in that embodiment. Rather, the features of one embodiment can also be used in other embodiments or combined with features in other embodiments to obtain another embodiment, and all such embodiments should fall within the protection scope of this invention.

[0034] In the following description, directional terms such as "up," "down," "left," and "right" are used. It should be understood that these directional terms refer to the directions shown in the figures. The use of these terms is for descriptive convenience and not to limit the scope of this disclosure. When the expansion valve is installed in other orientations, the corresponding directions will change. Furthermore, in the following description, terms such as "a," "an," and "the" are not intended to limit the technical solutions of this disclosure. Those skilled in the art should understand that a feature modified as "an" can also include the meaning of "a plurality of," and technical solutions including "a plurality of" the described features also fall within the scope of this disclosure.

[0035] This disclosure relates to an expansion valve, particularly an electronic expansion valve, comprising two orifices forming a throttling orifice, namely, a first orifice and a second orifice. Under a first pressure differential, only the second orifice is open, thereby allowing fluid to flow through the throttling orifice formed by the second orifice. Under a second pressure differential, both the first and second orifices are open, thereby allowing fluid to flow through the throttling orifice formed by the first and second orifices. For example, in the case of a constant-capacity compressor, the first pressure differential typically corresponds to a higher pressure differential, in which case opening a single orifice is sufficient to meet the requirement of a smaller mass flow. Conversely, the second pressure differential typically corresponds to a lower pressure differential, and by opening both the first and second orifices, the requirement of a larger mass flow is met. The first pressure differential typically occurs, for example, when the ambient temperature is high, such as 40 to 45 degrees Celsius, and the system temperature is at a high temperature of 55 or even 60 degrees Celsius, but the temperature of the vehicle compartment or system needs to be rapidly reduced to a lower temperature, such as 10 degrees Celsius. In this case, the compressor compresses the refrigerant to a higher pressure, such as 30 bar, thereby creating a larger first pressure differential. At this time, the mass flow is small, so only the second orifice is opened. On the other hand, when the ambient temperature drops to, for example, 30 degrees Celsius, the cooling demand decreases, for example, it is necessary to reduce the temperature of the vehicle compartment or system to 15 degrees Celsius. At this time, there is a higher mass flow, which requires a larger orifice. In this case, both the first and second orifices are opened to meet this requirement.

[0036] The following reference Figure 1-9 Detailed description of preferred embodiments according to this disclosure, wherein, Figure 1 This is a cross-sectional view showing the overall structure of a dual-orifice expansion valve. (See image.) Figure 1 As shown, the dual-orifice expansion valve 100 can be inserted into a valve block 200, thereby connecting to a refrigeration system (not shown). The valve block 200 includes an inlet 210 and an outlet 220, and the dual-orifice expansion valve 100 is inserted into an orifice 230 of the valve block, thereby positioning it between the inlet 210 and the outlet 220, and throttling the fluid from the inlet 210.

[0037] Combined with reference Figure 2-9 The dual-orifice expansion valve 100 includes a housing 1, which comprises an upper housing 101 and a lower housing 102. The upper housing 101 is shown in the figures as an upper tube, but this disclosure is not limited thereto. The upper housing 101 can be sealingly connected to the lower housing by various methods commonly used in the art, such as welding, bonding, riveting, threaded connection, etc., and optionally a seal (not shown) can be included between the two.

[0038] A valve chamber 103 is formed within the lower housing 102. This valve chamber 103 is, for example, formed as a cylindrical cavity. The movable first valve element 2, which will be described later, is slidably disposed within and coaxially with the valve chamber 103 in the vertical direction. A fluid inlet 4 may be formed on the side wall of the valve chamber 103, and a fluid outlet 5 is formed coaxially at the bottom of the valve chamber 103. When the expansion valve 100 is inserted into the valve block 200, the fluid inlet 4 communicates with the inlet 210 of the valve block 200, and the fluid outlet 11 communicates with the outlet 220 of the valve block 200.

[0039] like Figure 2 As shown, the inner diameter of the fluid outlet 11 is smaller than the inner diameter of the valve chamber 103, thus forming a first orifice 5 at the junction of the valve chamber 103 and the fluid outlet 11.

[0040] On the inner circumferential surface of the lower housing 102, along the axial direction of the valve chamber 103, a first guide portion 12 is formed. That is, the first guide portion 12 is formed by the inner circumferential surface of the lower housing 102 having a certain length in the axial direction. When the movable first valve element 2, which will be described below, is inserted into the valve chamber, the inner circumferential surface can slide into contact with the outer circumferential surface of the first valve element, and the first valve element 2 is guided by the first guide portion 12.

[0041] The movable first valve element 2 is generally cylindrical, having a cylindrical inner cavity for insertion into the second valve element 3, which will be described below. It includes a main body portion 24 occupying the majority of the first valve element in the axial direction and a diameter-reduced portion 21 located at the lower part of the main body portion, on which a fluid inlet 22 is formed. A second orifice 7 is coaxially formed within the lower end face of the cylindrical first valve element 2, communicating with the fluid outlet 11 of the housing 1. A tapered inclined surface 23 is formed on the outer peripheral edge of the lower end face, which can engage with the first orifice 5 formed on the lower housing 102 to open or close the first orifice 5.

[0042] The outer surface of the main body 24 forms a sliding contact with the first guide portion 12 of the lower housing 1, thereby directly guiding the movement of the first valve element 2 in the axial direction by the first guide portion 12 of the lower housing 1. The length of the first guide portion 12 in the axial direction is greater than the outer diameter of the main body of the first valve element 2, that is, the ratio of this length to the outer diameter of the main body of the first valve element 2 is greater than 1.0, preferably greater than 1.3, and more preferably greater than 1.5, thereby ensuring that the movement of the first valve element 2 is adequately guided by the first guide portion 12.

[0043] A second valve element 3 is inserted into the inner cavity of the first valve element 2, so that the second valve element 3 can move in the inner cavity of the first valve element 2 along the axial direction.

[0044] As shown in the figure, the second valve element 3 is coaxially disposed within the first valve element 2, including a generally cylindrical body portion 31 with a first diameter and a generally cylindrical valve head portion 32 with a second diameter, the first diameter being larger than the second diameter. The first diameter of the body portion 31 of the second valve element is substantially equal to the inner diameter of the body portion 24 of the first valve element 2. Thus, the outer surface of the body portion 31 of the second valve element 3 is in sliding contact with the inner surface of the body portion 24 of the first valve element 2. During the movement of the second valve element 3, through the sliding contact between the two, the second valve element 3 is directly guided by the inner surface of the body portion 24 of the first valve element 2. Thus, the inner surface of the body portion 24 of the first valve element 2 constitutes a second guide portion 13 that guides the movement of the second valve element 3.

[0045] The length of the second guide portion 13 along the axial direction is preferably greater than the outer diameter of the main body of the second valve element 3, that is, the ratio of the length of the second guide portion 13 to the outer diameter of the main body of the second valve element 3 is greater than 1.0, preferably greater than 1.3, and more preferably greater than 1.5, thereby fully ensuring the guiding effect on the second valve element 3.

[0046] The valve head portion 32 of the second valve element 3 includes a tapered end, which engages with the second orifice 7 of the first valve element 2 to open, close, or change the opening degree of the first orifice 7.

[0047] The expansion valve 100 according to this disclosure also includes an actuator 10 connected to the second valve element 3 to drive the second valve element 3. The actuator 10 may be, for example, a linear actuator as described in the European Patent EP3387304B1 granted to the applicant or an actuator described in PCT application WO2020 / 127062A1 entitled "Electronic Expansion Valve," filed on December 16, 2019, both of which are incorporated herein by reference in their entirety.

[0048] The actuator 10 may be, for example, in the form of a rotary motor, and may be, for example, a stepper motor, including a stator 104 and a rotor 105, the rotor 105 being operatively connected to a shaft 106. Figure 1As shown, the rotor 105 and shaft 106 are rotatably supported within the upper housing 101 (upper tube) via bearings (not identified). An external thread 107 is formed at the lower end of the shaft 106, and a nut 108 rotatably engages this thread 107, thereby causing the nut 108 to move up and down axially as the shaft 106 rotates. Simultaneously, the nut 108 can be guided by a guide feature provided within the upper housing 101 (upper tube), such as a guide rail (not identified), in which case the nut 108 may be provided with a guide groove (not identified) that mates with the guide rail.

[0049] Nut 108 is connected to the second valve element 3 via clip 15. This connection method is described, for example, in PCT application WO2020 / 127062A1 entitled “Electronic Expansion Valve” filed by the applicant on December 16, 2019, which is incorporated herein by reference in its entirety.

[0050] Specifically, a groove 14 is formed near the upper end of the second valve element 3 along the circumferential direction, a roughly U-shaped clip 15 is engaged in the groove 14, and there is a radial clearance 16 between the clip 15 and the groove 14 (e.g., Figure 3 As shown), this allows for a certain radial play between the second valve element 3 and the clamp 15. The function of this radial clearance is that, since the second valve element 3 is guided over a long range by the second guide portion 13 of the first valve element 2, and the nut 108 connected to the clamp 15 moves along the shaft 107, if the axis of movement of the second valve element 3 is not perfectly aligned with the axis of movement of the nut 108 due to manufacturing or assembly tolerances, the existence of this clearance can absorb this misalignment error, so that the two will not interfere with each other.

[0051] The nut 108 is connected to the second valve element 3 via the clamp 15. The rotation of the actuator 10 is converted into the up-and-down movement of the nut 108, thereby positioning the second valve element 3 in the first position of closing the second orifice 7 (e.g., Figure 2 (as shown) and the second position where the second opening 7 is fully opened (as shown) Figure 6 Move between (as shown).

[0052] As shown in the figure, a channel 6 is also formed within the housing 1, extending substantially parallel to the valve chamber 103 to connect the fluid inlet 4 of the housing to the upper side of the first valve element 2. This allows pressure from the fluid inlet 4 to be introduced to the upper side of the first valve element 2, biasing the first valve element 2 toward the first orifice to close the first orifice 5. Thus, in the expansion valve of this disclosure, the spring used to bias the first valve element 2 toward the first orifice 5 is omitted.

[0053] As shown in the figure, a flange 8 is provided on the inner circumferential surface of the upper end of the first valve element 2. This flange 8 can be connected to the first valve element 2 by any method known in the art, such as welding, bonding, or threaded connection. Alternatively, the flange 8 can be integrally formed with the first valve element 2. The flange 8 protrudes radially inward from the inner circumferential surface of the first valve element 2. Correspondingly, the diameter of the upper part of the main body of the second valve element 3 is reduced, allowing the upper part to pass through the inner diameter of the flange 8. This forms a shoulder 9 on the outer circumferential surface of the main body of the second valve element 3. When the second valve element 3 is in the second position, this shoulder 9 can abut against the flange 8 from below, thereby causing further movement of the second valve element 3 to move the first valve element 2 upward.

[0054] Below, we will refer to Figure 2-9 The working process of the dual-orifice expansion valve according to this disclosure is described.

[0055] First, refer to Figure 2 and Figure 3 , Figure 2 and 3 This illustrates a state where the first orifice 5 is closed by the first valve element 2 and the second orifice 7 is closed by the second valve element 3. In this state, the second valve element 3 is in the first position, such as... Figure 2 and 3 As shown, in this state, the tapered end of the valve head portion 32 of the second valve element 3 is inserted into the second orifice 7 and abuts against the edge of the second orifice 7, thereby closing the second orifice 7. Simultaneously, the tapered inclined surface 23 of the first valve element 2 abuts against the edge of the first orifice 5 of the housing 1, thereby closing the first orifice 5. Also, as... Figure 3 As shown, the shoulder 9 of the second valve element 3 is away from the flange 8 of the first valve element 2. At this time, the first valve element 2 is pressed onto the first orifice 5 by means of the pressure from the fluid inlet 4.

[0056] Further reference Figure 4 and 5 , Figure 4 and Figure 5 The diagram shows the second orifice 7 open. Under the action of actuator 10, the second valve element 3 is moved upward, causing the tapered end of the valve head portion 32 to gradually move away from the second orifice 7, thereby providing an adjustable throttling area. At this time, as... Figure 5 As shown, the shoulder 9 of the second valve element moves upward and the distance between the shoulder 9 and the flange 8 decreases.

[0057] Reference Figure 6 and 7 , Figure 6 and 7 The diagram shows the second valve element 3 in its second position, where the second orifice is fully open while the first orifice remains closed. At this time, as... Figure 7As shown, the shoulder 9 of the second valve element 3 contacts the flange 8 of the first valve element 2 from below.

[0058] Further reference Figure 8 and 9 , Figure 8 and 9 This shows the state where both the first and second orifices 5 and 7 are open. (See diagram.) Figure 8 As shown, the second valve element 3 is further moved by the actuator 10, causing the second valve element 3 to lift (move) the first valve element 2 upward through the engagement of the shoulder 9 and the flange 8, thereby causing the tapered inclined surface 23 of the first valve element 2 to leave the edge of the first orifice 5, opening the first orifice 5 and thus providing a larger throttling area.

[0059] It can be seen that by concentrically arranging the valve chamber 103 of the housing 1, the first valve element 2, and the second valve element 3, with the first valve element 2 directly guided by the inner circumferential surface of the valve chamber 103 and the second valve element 3 directly guided by the inner circumferential surface of the first valve element 2, the first and second valve elements are well guided and will not move radially during movement, for example. This simplifies the guiding structure and facilitates concentric alignment of the first and second valve elements with their respective first and second orifices. Furthermore, especially when the first or second orifice is open, because the first and second valve elements are sufficiently guided and confined by the housing and the first valve element respectively, vibration, especially high-frequency vibration, is prevented when pressurized fluid passes through, thus reducing noise during valve operation.

[0060] Furthermore, by introducing the pressure of the incoming fluid onto the upper side of the first valve element and acting on it, the spring commonly used in conventional expansion valves is eliminated, thereby reducing the number of parts and simplifying the assembly process. Additionally, by providing a channel within the housing parallel to the first and second valve elements, the pressure within the valve chamber can be quickly balanced, preventing particles, such as those contained in the refrigerant, from entering the interface between the relatively sliding elements, thus avoiding expansion valve malfunctions.

[0061] Although the dual-orifice expansion valve according to this disclosure has been described in detail above, it should be understood that the foregoing exemplary embodiments and advantages are merely illustrative and should not be construed as limiting the scope of this disclosure. This teaching can be readily applied to other types of devices. Furthermore, the description of exemplary embodiments of this disclosure is intended to be illustrative and not to limit the scope of the claims, and many alternatives, modifications, and variations will be apparent to those skilled in the art due to the description of this disclosure.

Claims

1. A dual orifice expansion valve comprising a first orifice (5) and a second orifice (7) and being operable at a first differential pressure with a flow path through the second orifice (7) and at a second differential pressure with a flow path through both the first orifice (5) and the second orifice (7), the dual orifice expansion valve comprising: a housing (1) comprising a fluid inlet (4), a fluid outlet (11) and the first orifice (5) in a flow path from the fluid inlet to the fluid outlet; a movable first valve element (2) arranged within the housing (1) and movable relative to the housing (1) to vary the opening of the first orifice (5) and having an axial direction, wherein the first valve element (2) is provided with the second orifice (7) in the flow path; a movable second valve element (3) arranged within the first valve element (2) and movable relative to the first valve element (2) to vary the opening of the second orifice (7); and an actuator (10) causing the second valve element (3) to move relative to the first valve element (2) between a first position in which the second orifice has a first opening and a second position in which the second orifice has a second opening different from the first opening, wherein the housing is provided with a first guide portion (12) constituted by an inner circumferential surface of a lower housing having a length in the axial direction, an outer surface of the first valve element being in slidable contact with the first guide portion such that movement of the first valve element is guided by the first guide portion; and the first valve element is provided with a second guide portion (13), an outer surface of the second valve element being in slidable contact with the second guide portion such that movement of the second valve element is guided by the second guide portion; wherein the housing (1) is provided with a channel (6) configured to lead fluid pressure from the fluid inlet to an upper side of the first valve element (2) to press the first valve element (2) against the first orifice (5) to close the first orifice.

2. The dual orifice expansion valve of claim 1, wherein, the first valve element is hollow cylindrical, its outer circumferential surface being guided by the first guide portion (12), wherein the ratio of the length of the first guide portion (12) along the axial direction to the outer diameter of the first valve element (2) is greater than 1.

0.

3. The dual orifice expansion valve of claim 2, wherein, the ratio of the length of the first guide portion (12) along the axial direction to the diameter of the first valve element (2) is greater than 1.

3.

4. The dual orifice expansion valve of claim 2, wherein, the second valve element (3) comprises a cylindrical body portion, its outer circumferential surface being guided by the second guide portion (13), wherein the ratio of the length of the second guide portion along the axial direction to the outer diameter of the cylindrical body portion of the second valve element is greater than 1.

0.

5. The dual orifice expansion valve of claim 4, wherein, The ratio of the length of the second guide portion along the axial direction to the outer diameter of the cylindrical body portion of the second valve element is greater than 1.

3.

6. The dual orifice expansion valve of claim 1, wherein, The expansion valve is operable at the first pressure difference or at a second pressure difference, the second pressure difference being lower than the first pressure difference.

7. The dual orifice expansion valve of any of claims 1-6, wherein, The first valve element (2) is provided with a flange (8) on its inner surface, and the second valve element (3) is provided with a shoulder (9) on its outer surface, the shoulder (9) abutting against the flange (8) when the second valve element is moved to the second position by the actuator.

8. The dual orifice expansion valve of claim 7, wherein, In the second position where the shoulder (9) abuts against the flange (8), further movement of the second valve element (3) by the actuator (10) causes the first valve element (2) to move to open the first orifice (5).

9. The dual orifice expansion valve of any of claims 1-6, wherein, The actuator (10) is connected to the second valve element (3) by a floating connection structure.

10. The dual orifice expansion valve of claim 9, wherein, The floating connection structure includes a groove (14) formed on the outer surface of the second valve element and a clip (15) connected to the actuator, the clip (15) being engaged with the groove (14) with a radial play.

11. The dual orifice expansion valve of any of claims 1-6, wherein, The housing includes an upper housing (101) and a lower housing (102), the actuator being provided in the upper housing (101), and the first guide portion being formed on the lower housing (102).

12. A refrigeration system comprising at least one double-orifice expansion valve according to any one of claims 1 to 11.

Images