Valve actuator assembly

Abstract

A pressure independent control valve (PICV) assembly comprising a PICV having an inlet side and an outlet side in a valve housing and an amount control arrangement for dynamic control of the amount of liquid flowing through the PICV, the PICV comprising a valve connection element; and an actuator configured for controlling the amount control arrangement of the PICV, the actuator comprising an actuator connection element, said actuator and PICV being irreversibly separable when in an assembled configuration in which the valve connection element and the actuator connection element are in mutual engagement.

Description

[0001] Title of Invention

[0002] Valve actuator assembly

[0003] Technical Field

[0004] The present disclosure relates to a valve assembly comprising a pressure independent control valve and an actuator.

[0005] Background Art

[0006] Pressure independent control valves (PICVs) are typically installed with an actuator for automatic adjustment of an opening between an inlet side and an outlet side to control the flow through the PICV. Typically, PICV and the actuator are provided as separate parts or parts arranged to be separated and assembled by an installer. Separated or separable actuator and PICV parts have the advantage that either part can be exchanged if the counterpart breaks in contrast to inseparable parts. Additionally, many current PICV solutions comprise a manually adjustable flow pre-set function comprised in the PICV and having an access point arranged between the actuator and PICV such that it is only accessible when the actuator and PICV are separated. However, separable parts allow for mistakes during installation which is especially prevalent in PICVs where an amount control arrangement is adjusted by an actuator. Such mistakes may arise where the actuator communicates with the amount control arrangement via an actuator spindle. The actuator spindle has an intended position for assembly. Incorrect positioning of the actuator spindle during assembly may lead to malfunction e.g. if the actuator spindle axially pushes a valve spindle too far into the valve housing, the latter case potentially leading to a damaged PICV and / or actuator. PICVs of this kind are known e.g. from WO 2006 / 136158 Al and WO 2009 / 135490 A2, both of the present applicant. PICVs of this kind are used for many different purposes, e.g. regulation of heating, such as floor heating, heating in large buildings, cooling or similar.

[0007] Thus, WO 2009 / 135490 Al describes a PICV, in which the amount control arrangement is adapted so that the flow amount through the PICV can be dynamically adjusted within an independently pre-set flow amount range. An inner, cylindrical valve member is co-axial with a rotatable outer, cylindrical valve member, both valve members having a circumferentially extending cut-out, the pre-setting of the flow amount range being established by manual rotation of one valve member in relation to the other to provide a varying overlap of the cut-outs and thus a varying pre-set opening area. The valve members are furthermore movable together in the axial direction to vary the pre-set opening area provided by the circumferential overlap of the cut-outs, the valve members being connectable with an actuator to provide the dynamic flow amount adjustment by automatically controlling the common axial position of the valve members.

[0008] Summary of Invention

[0009] It is therefore an object to provide a pressure independent control valve, PICV, assembly which overcomes or at least alleviates the problems of the prior art.

[0010] In a first aspect of the present invention a pressure independent control valve (PICV) assembly comprises a PICV having an inlet side and an outlet side in a valve housing and an amount control arrangement for dynamic control of an amount of liquid flowing through the PICV. The PICV comprises a valve connection element. The assembly further comprises an actuator configured for controlling the amount control arrangement of the PICV. The actuator comprises an actuator connection element. The actuator and PICV are irreversibly separable when in an assembled configuration in which the valve connection element and the actuator connection element are in mutual engagement.

[0011] By having an irreversibly separable actuator and PICV, an element of the PICV assembly is destroyed upon separation of the actuator and PICV. Thus in an embodiment the actuator connection element and / or the valve connection element is destroyed upon separation of the actuator and PICV.

[0012] The term PICV is throughout the application also referred to as valve.

[0013] Possible embodiments of the invention are described in the dependent claims.

[0014] In preferred embodiments, the actuator connection element and / or the valve connection element is destroyed upon separation of the actuator and valve. Destroyed in this sense is to be understood in that the connection element of the actuator and / or the PICV arranged to provide an assembled condition of the actuator and valve is permanently incapable of re-establishing the assembled condition. This has the potential advantage that the PICV assembly can be provided as a single unit which the installer is not inclined to separate during installation because the parts cannot be reassembled but can be separated if either part malfunctions and a replacement of the malfunctioning part is needed.

[0015] The actuator comprises an actuator unit constituting an actuating mechanism. The actuator further comprises the actuator connection element configured to engage with the valve connection element. The assembled condition is obtained when the connection elements are mutually engaged such that the actuator connection and the valve connection are irreversibly separable. The valve connection element and the actuator connection element may be fixedly connected in the assembled configuration of the control valve assembly. In this context, fixedly connection is to be understood as in it will require considerable effort to separate the connection elements, preferably in a controlled but irreversible manner. This has the potential advantage that the irreversible separation does not occur by accident e.g. during regular maintenance of the valve assembly.

[0016] Preferably, only the actuator connection element is destroyed when the actuator and PICV are separated from the assembled configuration. The inventors have realised that in typical PICV assemblies, the service life of the actuator is shorter than the service life of the PICV and therefore the actuator often malfunctions first. It is therefore a potential advantage if only the actuator connection element is destroyed when the actuator and PICV are separated. This allows a new actuator to be attached to the existing valve.

[0017] Alternatively, the valve connection element or both connection elements are destroyed when the valve and the actuator are separated.

[0018] The actuator connection element may comprise a plurality of arms circumferentially disposed around an axis A and extending along the axis.

[0019] The valve connection element is preferably comprised in a top piece, such as a bonnet, of the PICV. Preferably, the valve connection element comprises an edge. The edge may form part of a collar extending from the valve top piece. Alternatively and / or additionally, the edge may form part of a recess or hole in the valve top piece, the recess or hole being configured to receive at least a part of the actuator connection element.

[0020] The plurality of arms and the edge may form the irreversibly separable connection between the actuator and valve by providing a snap connection between the edge and a head arranged on each of the arms, respectively. The plurality of arms ensure that the actuator is not easily separable from the valve and that destruction, e.g. by either rupture or permanent deformation, of at least some of the arms is needed to separate the parts. In some embodiments, the head on each arm extends towards the axis A. Alternatively, the head on each arm extends away from the axis A.

[0021] In embodiments where the heads extend towards the axis A the arms may enclose the valve connection element.

[0022] In embodiments where the heads extend away from the axis A, the arms may be received in the valve such as in a bonnet or other form of top piece of the valve.

[0023] The PICV assembly may further comprise a restrictive element encircling the plurality of arms. This has the potential advantage of providing further restrictions to separation of the actuator and PICV.

[0024] In some of these embodiments, irreversibly separable is to be understood as the restrictive element being destroyed.

[0025] The skilled person may envision other ways to provide the irreversibly separable parts.

[0026] Pressure independent control valve

[0027] The PICV is for use in liquid-carrying systems.

[0028] Being a PICV (pressure independent control valve) the PICV inherently comprises the amount control arrangement and a differential pressure maintaining arrangement, often denoted a differential pressure governor or a differential pressure regulator, for maintaining a constant differential pressure across the amount control arrangement.

[0029] In an embodiment the differential pressure maintaining arrangement comprises a rolling diaphragm and a cup-shaped valve member movable together along an axis of the valve, e.g. coinciding with the axis A mentioned above, the valve member and diaphragm setting themselves in a balance between an upstream pressure on the one hand and a downstream pressure as well as a spring force on the other hand, e.g. as disclosed in Applicant's WO 2009 / 135490 A2.

[0030] The amount control arrangement may be adapted for dynamic adjustment of the flow amount through the PICV within a flow amount range between a maximum setting and a minimum, e.g. zero. As described in the above-mentioned prior art, PICVs may comprise a manual pre-setting of the flow amount range to establish a maximum flow through the valve. The flow may then be further adjusted in the range below that maximum flow by means of the actuator.

[0031] In preferred embodiments, the dynamic adjustment of the flow amount through the valve is solely controlled with the actuator. This has the advantage that manual pre-setting is not needed.

[0032] The actuator preferably comprises an actuator spindle for controlling the amount control arrangement. Preferably, the actuator spindle is configured for axial movement.

[0033] The inventors have realized that by providing an amount control arrangement solely controlled by the linear actuator, a PICV assembly with an irreversibly separable actuator and PICV can be achieved that provides the possibility of adjusting the maximum setting of flow without removal of the actuator. The inventors have realised that it is an advantage to have an amount control arrangement that can be solely controlled by the actuator when having an irreversibly separable actuator and PICV, because the actuator and PICV are not to be separated unless either part malfunctions.

[0034] The actuator preferably has a total stepping range in the range of 3 to 9 mm, more preferably 5 to 7 mm, even more preferably 6 mm. The inventors have realized that an actuator with the preferred total stepping range allows for a sufficiently large flow amount regulation through the PICV to make the manual pre-setting known from the prior art superfluous. By having an actuator with the preferred total stepping range the dynamic adjustment of the flow amount may be controlled without removal of the actuator from the PICV.

[0035] The actuator preferably has a minimal step size of at least 2 pm. The inventors have realized that an actuator with the preferred minimal step size allows for sufficiently small variations in the flow amount variation.

[0036] Preferably, the actuator is a linear actuator configured to provide a linear movement. Alternatively, the actuator may be a rotary actuator.

[0037] Preferably, the amount control arrangement comprises a valve spindle configured for being controlled by the actuator. The valve spindle is preferably configured for axial movement along the axis A when controlled by the actuator. Alternatively, the control amount arrangement is configured to adjust the flow amount by axial rotation, preferably around the axis A, of a part of the control amount arrangement.

[0038] In preferred embodiments, the valve assembly comprises an actuator spindle and a valve spindle both configured for axial movement along the axis A.

[0039] The amount control arrangement may comprise a plunger attached to the spindle and arranged to adjust an orifice size between the inlet side and outlet side of the valve by linear movement of the plunger. A rubber seat may be arranged in the circumference of the orifice to provide a tight seal between the plunger and the valve housing when the valve is in a closed condition.

[0040] The plunger may comprise a conical profile in a plane extending along the axis A.

[0041] A person skilled in the art will appreciate that any one or more of the above aspects of this disclosure and embodiments thereof may be combined with any one or more of the other aspects of the disclosure and embodiments thereof.

[0042] Brief Description of Drawings

[0043] In the following description, embodiments of the PICV assembly will be described based on nonlimiting exemplary embodiments and with reference to the drawings, of which

[0044] Fig. 1 shows an exploded view of a PICV assembly according to an embodiment of the present disclosure,

[0045] Fig. 2A shows a cross-sectional view of a PICV assembly according to an embodiment of the present disclosure.

[0046] Fig. 2B shows a close-up of a section of the PICV assembly shown in Fig. 2A.

[0047] Similar reference numerals are used for similar elements across the various embodiments and figures described herein.

[0048] Fig. 3 shows an alternative embodiment of the features of highlighted area B of Fig. 2 in an embodiment a PICV assembly according to the invention.

[0049] Description of Embodiments

[0050] Referring to Figs. 1 - 2 two embodiments of a pressure independent control valve (PICV) assembly 100 are shown. Fig. 1 shows an exploded view of a PICV assembly 100 according to the invention and Fig. 2 shows a cross-section of a PICV assembly 100 according to the invention. The PICV assembly 100 is shown to comprise a PICV 10 and an actuator 50.

[0051] The PICV 10 has an inlet side 2 and an outlet side 3 in a valve housing 11.

[0052] The amount control arrangement 20 is shown to comprise a plunger 21 arranged on an end of a valve spindle 15. As best shown in Fig. 2B, a rubber seat 25 and a gasket 26 is arranged on the plunger 21. The rubber seat 25 is adapted to engage with a valve housing seat 11a to provide a closed condition of the valve 10. The rubber seat 25 is adapted to provide a proper seal between the valve housing seat 11a and the plunger 21 when the valve assembly is in the closed condition. The amount control arrangement 20 provides an orifice 12 between the plunger 21 and the valve housing 11 when the valve 10 is in an open condition. The size of the orifice 12 can be changed by axial movement of the valve spindle 15 via an actuator spindle 56. To reduce the orifice size, the valve spindle 15 is moved towards the valve housing seat 11a. To increase the orifice size, axial movement of the actuator spindle 56 combined with the spring 18 exerting a force on the valve spindle moves the valve spindle 15 away from the valve housing seat 11a along the axis A.

[0053] In the present embodiment a differential pressure maintaining arrangement comprises a rolling diaphragm 134 and a cup-shaped valve member 132 movable together along the axis A of the valve. During operation the cup-shaped valve member 132 and the rolling diaphragm 134 are setting themselves in a balance between an upstream pressure Pl on the one hand and a downstream pressure as well as a force of a second spring 137 on the other hand. To provide for the upstream pressure to act on the intended side of the rolling diaphragm 134 and the cup-shaped valve member 132 a capillary channel 139 is provided, eventually leading the pressure Pl at the inlet side 2 to the upper side of the intended side of the rolling diaphragm 134 and the cupshaped valve member 132 as seen in Fig. 2.

[0054] In the present embodiment, the cup-shaped valve member 132 cooperates with a second valve housing seat 133 arranged radially outside the first valve housing seat 11a to define a restricted opening through which the flow of liquid through the PICV must pass thus providing a pressure drop to maintain a substantially constant pressure drop across the amount control arrangement 20. Downstream of the orifice 12 and upstream of the restricted opening partly defined by the cup-shaped valve member 132 the fluid has a pressure P2.

[0055] Figs 1-2 show the actuator 50 comprising an actuator unit 51, an actuator housing 55, an actuator spindle 56, and an actuator lid 59. The actuator has an actuator connection element 57 comprised in the actuator housing 55.

[0056] In the shown embodiments, the valve connection element 17 comprises a collar adapted to engage with the actuator connection element 57. The connection element 17 is arranged on a top piece 16 i.e. a bonnet of the valve.

[0057] As best shown in the highlighted area B of Fig. 2A, each arm of the plurality of arms has a longitudinal element 57i extending from the actuator housing and a head 57ii extending towards the axis A. The plurality of snap connections provides the irreversibly separable connection.

[0058] In the embodiment shown in Fig. 2A, the valve spindle 15 is configured for being controlled by the actuator 50 via the actuator spindle 56. The actuator 50 is a linear actuator adapted to provide an axial movement of the actuator spindle 56 along the axis A through the valve housing 10. The actuator spindle 56 and the valve spindle 15 are both arranged along the axis A, the axial movement of the actuator spindle 56 is configured to provide an axial movement of the valve spindle 15. Fig. 3 shows an alternative embodiment of the PICV assembly in which the actuator connection element is received in the PICV and wherein the heads of the actuator connection element extend away from the axis A.

Claims

Patent claims1. A pressure independent control valve (PICV) assembly (100) comprising a PICV (10) having an inlet side (2) and an outlet side (3) in a valve housing (11) and an amount control arrangement (20) for dynamic control of the amount of liquid flowing through the PICV (10), the PICV (10) comprising a valve connection element (17); and an actuator (50) configured for controlling the amount control arrangement (20) of the PICV, the actuator (50) comprising an actuator connection element (57), said actuator (50) and PICV (10) being irreversibly separable when in an assembled configuration in which the valve connection element (17) and the actuator connection element (57) are in mutual engagement.

2. A PICV assembly (100) according to claim 1, wherein the actuator (50) comprises an actuator spindle (56) for controlling the amount control arrangement (20).

3. A PICV assembly (100) according to any one of the preceding claims, wherein the amount control arrangement (20) comprises a valve spindle (15) configured for being controlled by the actuator (50).

4. A PICV assembly (100) according to any one of the preceding, wherein the connection elements (17; 57) are fixedly connected in the assembled configuration of the PICV assembly (100).

5. A PICV assembly (100) according to any one of the preceding claims, wherein the actuator connection element (57) is destroyed when the actuator (50) and PICV (10) are separated from the assembled configuration.

6. A PICV assembly (100) according to any one of the preceding claims, wherein the actuator connection element (57) comprises a plurality of arms configured to provide a snap-connection with an edge comprised in the control valve connectionelement (17).

7. A PICV assembly (100) according to any one of the preceding claims, wherein the dynamic adjustment of the flow amount through the PICV (10) is solely controlled with the actuator (50).

8. A PICV assembly (100) according to any one of the preceding claims, wherein the PICV (10) comprises a differential pressure maintaining arrangement.

9. A PICV assembly (100) according to claim 8, wherein the differential pressure maintaining arrangement comprises a rolling diaphragm (134) and a cup-shaped valve member (132) configured for moving together along an axis of the valve, and where the cup-shaped valve member (132) and rolling diaphragm (134) are adapted for setting themselves in a balance between an upstream pressure (Pl) on the one hand and a downstream pressure (P3) and a force of a spring (137) on the other hand.

10. A PICV assembly (100) according to claim 9, wherein the rolling diaphragm (134) and the cup-shaped valve member (132) are configured for moving together along the axis A.

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