DK179688B1

DK179688B1 - Control valve for heating and/or cooling system

Info

Publication number: DK179688B1
Application number: DKPA201770612A
Authority: DK
Inventors: Enøe Møller Carsten
Original assignee: Flowcon International Aps
Priority date: 2017-08-14
Filing date: 2017-08-14
Publication date: 2019-03-26
Also published as: DK201770612A1

Abstract

A control valve (1) for controlling flow of liquid in a heating and/or cooling installation with a pressure regulating arrangement for maintaining a constant differential pressure between a first pressure (P1) in the control valve (1) and a second pressure (P2) in the control valve (1). The pressure regulating arrangement has a movable throttle member (16) that is urged by the first pressure (P1) to increase the flow resistance and that is urged by a resilient member (20) and by the second pressure (P2) to decrease the flow resistance. The movable throttle member comprises a rolling diaphragm (16) that interacts with a plurality of exit openings (18). The rolling diaphragm (16) has a circular circumference attached to an annular body (11) that is arranged in the control valve (1). The plurality of exit openings (18) is formed radially through the annular body (11). At least one pressure communication channel (28) extends in said annular body (11) for communicating the first pressure (P1) from a first location in the control valve (1) on one axial side of said rolling diaphragm (16) to a second location in the controlvalve (1) on the other axial side of said rolling diaphragm (16).

Description

CONTROL VALVE FOR HEATING AND/OR COOLING SYSTEM

TECHNICAL FIELD

The disclosure relates to a control valves that includes a differential pressure control function, in particular to control valves for control of fluid in a heating and/or cooling installation of e.g. a building, a ship or a plant.

BACKGROUND

This type of control valve is used for hydraulic balancing in a system that comprises a large number of individual heating circuits. These control valves are used to control the flow of heating or cooling fluids through individual circuits in the system, and thus ensure that each individual heating circuit is provided with a desired flow of heating or cooling liquid so that the whole system is balanced. An individual heating circuit can be a section of a floor heating, of a ceiling cooling system, a space heating radiator or a group of several space heating radiators.

This type of control valve is provided with a differential pressure control function that includes a movable throttling element that is affected on one side by a first pressure P1 and on the other side by second pressure P2 and a resilient force, for example from a helical spring. The second pressure P2 is lower than the first pressure P1 and the characteristics of the resilient force determine the pressure differential that is maintained. Thus, a stiffer spring results in a higher differential pressure. Such a differential pressure control function is e.g. used to maintain a constant differential pressure over an adjustable size opening. With a constant differential pressure over the adjustable size opening the flow can be accurately regulated by adjusting the adjustable size opening. The adjustable size opening can be manually adjusted or be adjusted using an actuator, such as an electric actuator. The adjustment can be automatic by an electronic control unit or be in response to a control signal. Typically, the typically, adjustment is manual and the control valves are arranged in the return line.

However, there are other ways to use a differential pressure function in a control valve that do not relate to an adjustable size opening.

WO2008052553 discloses a control valve with a rolling membrane as the throttling member and the resilient force comes from a helical spring acting on the rolling membrane. The first higher pressure P1 and the second low pressure P2 originate both on one of the same side of the rolling membrane. Therefore, a pressure communication channel is provided in a central shaft that extends through the rolling membrane for communicating the first high pressure P1 to the opposite side of the rolling membrane. The central shaft extends through a collar in a central opening in the rolling membrane. The collar fits slidingly over the central shaft since the rolling membrane must be allowed to move freely in response to the first pressures P1 on its one side and the second pressure P2 and the helical spring on its other side. The rolling membrane must therefore be free move relative to the central shaft. A small clearance is needed between the collar and the central shaft to ensure free movement of the rolling membrane. However, such a clearance will always form a leak path and consequently, it is not possible to avoid small amount of leakage even if the valve of WO2008052553 is in its fully closed position. Though small, such leakage may over time accrue and form a substantial energy loss for the system in which is used.

US 2015/0198258 discloses a control valve for controlling flow of liquid in a heating and/or cooling installation, the control valve comprising: a pressure regulating arrangement configured for maintaining a substantially constant differential pressure between a first pressure (P1) in the control valve and a second pressure (P2) in the control valve, the pressure regulating arrangement comprises a movable throttle member that is urged by the first pressure (Pl) to increase the flow resistance posed by the pressure regulating arrangement and that is urged by a resilient member and by the second pressure (P2) to decrease the flow resistance posed by the pressure regulating arrangement, the movable throttle member comprising a rolling diaphragm that interacts with a plurality of exit openings, the rolling diaphragm having a circular circumference attached to an annular body that is arranged in the control valve, the plurality of exit openings being formed radially through the annular body, having a pressure communication channel that communicates the pressure P1 at the inlet to the bottom end of the valve housing. This enables an actuator to close off the valve completely, so that no leak can occur between the inlet and the outlet. However, this solution only applies to the situation where the valve is completely closed, and leak across the membrane still occurs when the valve is not completely closed.

Consequently, there is a need for a control valve that overcomes or at least reduces the problems indicated above.

SUMMARY

The foregoing and other objects are achieved by the features of the independent claims. Further implementation forms are apparent from the dependent claims, the description and the figures.

According to a first aspect, there is provided a control valve for controlling flow of liquid in a heating and/or cooling installation, the control valve comprising a pressure regulating arrangement configured for maintaining a substantially constant differential pressure between a first pressure P1 in the control valve and a second pressure P2 in the control valve, the pressure regulating arrangement comprises a movable throttle member that is urged by the first pressure to increase the flow resistance posed by the pressure regulating arrangement and that is urged by a resilient member and by the second pressure P2 to decrease the flow resistance posed by the pressure regulating arrangement, the movable throttle member comprising a rolling diaphragm that interacts with a plurality of exit openings, the rolling diaphragm having a circular circumference attached to an annular body that is arranged in the control valve, the plurality of exit openings being formed radially through the annular body, characterized by at least one pressure communication channel extending in the annular body for communicating the first pressure P1 from a first location in the control valve on one axial side of the rolling diaphragm to a second location in the control valve on the other axial side of the rolling diaphragm.

By providing the pressure communication channel that communicates the first pressure P1 to the opposite side of the rolling diaphragm, without creating a passage through the rolling diaphragm it becomes possible to create a differential pressure control valve that does not have any leakage across the rolling diaphragm. Thus, process can be reduced and the control valve can be completely closed.

In a possible implementation of the first aspect the pressure communication channel opens to two axially spaced openings in the annular body.

In a possible implementation of the first aspect the exit openings 18 are axially extending elongated openings, and wherein the pressure communication channel axially extends between two axially extending exit openings.

In a possible implementation of the first aspect the control valve comprises a plurality of pressure communication channels, each pressure communication channel of the plurality extending between two axially extending exit openings.

In a possible implementation of the first aspect the plurality of exit openings are circumferentially distributed over the circumference of the annular body.

In a possible implementation of the first aspect the rolling diaphragm comprises a continuous body of material.

In a possible implementation of the first aspect the rolling diaphragm does not have any through going openings.

In a possible implementation of the first aspect the control valve further comprises a flow area regulator for regulating a flow area of at least one variable size entry opening through which the liquid flowing through the control valve 1 from an inlet opening to an outlet opening must pass.

In a possible implementation of the first aspect the control valve comprises an elongated, preferably rotation symmetric, valve body with opposite first and second longitudinal ends, the first end being provided with a with a closable inlet opening.

These and other aspects will be apparent from and the embodiment(s) described below.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following detailed portion of the present disclosure, the aspects, embodiments and implementations will be explained in more detail with reference to the example embodiments shown in the drawings, in which:

Figs. 1 and 2 are different side views of a control valve, Figs 3,4 and 6 are longitudinal-sectional views of the control valve of Figs. 1 and 2,

Fig. 5 is a cross-sectional view of the control valve of Figs. 1 and 2,

Fig. 7 is a longitudinal-sectional view of a functional element of Figs. 1 and 2, the functional element including a constant pressure differential function and a flow area adjustment function,

Fig. 8 is an enlarged detail of Fig. 7,

Fig. 9 is an exploded view of the valve of Figs. 1 and 2, Fig. 10 is an enlarged longitudinal-sectional view of the valve of Figs. 1 and 2 in an open position, but with internal thread instead of external threat for coupling an actuator to the control valve,

Fig. 11 is an enlarged longitudinal-sectional view of the valve of Fig. 10 in a closed position,

Figs. 12 and 13 show a plurality of control valves in a manifold of a floor heating or ceiling cooling system, and Figs. 14 and 15 show the manifold and control valves of Figs. 12 and 13 in cross-sectional and longitudinalsectional view, respectively.

DETAILED DESCRIPTION

A control valve is described with reference to Figs. 1 to

15. The control valve 1 comprises a valve body 2. The valve body 2 is generally rotation symmetric and comprises a part with a hexagonal outer contour and a cylindrical part 4. It should though be noted that the part with the hexagonal order does not need to have a hexagonal outer shape, the skilled person is familiar with other suitable shapes, such as e.g. a simple cylindrical shape.

The valve body 2 is at or near one of its longitudinal ends provided with thread for coupling with a linear actuator provided with corresponding thread, such as an electric actuator (not shown). The valve body 2 is also provided with thread for engaging thread of a housing or body, such as a manifold 40. Both the cylindrical part 4 and the part with the hexagonal outer have a hollow interior in which most of the components of the control valve 1 are arranged.

An axially movable activator 6 protrudes from the longitudinal end of the valve body 2 where the thread for coupling to an actuator is provided. The activator 6 protrudes from the valve body 2 for engaging an actuator (not shown). The activator 6 is arranged in to parts with a helical spring 38 therebetween in order to avoid application of excessive force to the components in control valve 1 by an actuator.

The opposite longitudinal end is part of the cylindrical part 4. The opposite longitudinal end is provided with an axial inlet opening 9. The cylindrical part 4 is provided with one or more radial outlet openings 7. The control valve 1 controls the flow from the axial inlet opening 9 to the radial outlet opening(s) 7.

Hereto, the control valve 1 comprises an arrangement for maintaining a constant differential pressure and an arrangement for adjusting the size of an adjustable size opening. In an embodiment the arrangement for maintaining the constant differential pressure maintains a constant differential pressure over the adjustable size opening.

An annular body 11 is disposed slidably inside the cylindrical portion 4 of the valve body 2, such that the annular body can rotate relative to the valve body 2 and move in the axial direction relative to the valve body 2. The fit between the annular body 11 and the cylindrical portion 4 is such that it is substantially sealing.

The differential pressure control function comprises a throttling member in the form of a rolling diaphragm 16. The rolling diaphragm 16 has a circular outer circumference that is secured to the annular body 11. The rolling diaphragm is supported by a diaphragm support member 14. A helical spring 20 acts on the diaphragm support member 14 and urges the rolling diaphragm 16 in a direction that reduces the throttling effect of the rolling diaphragm 16.

The annular body 11 is provided with a plurality of exit openings 18. The exit openings 18 extend radially through the annular body 11. The exit openings 18 can be formed as longitudinal slits that extend axially. The exit openings 18 are preferably circumferentially evenly distributed over the annular body 11.

The axial end of the annular body 11 closest to the axial inlet opening 9 is closed off by a bottom in the form of a disc member 15. The disc member 15 is provided with one or more first regulation openings 26.

The axial end of the annular body 11 furthest from the axial inlet opening is provided with a cover 12. The cover 12 is provided with a number of through going openings for pressure equalization.

The bottom with the disc member 15 is rigidly connected to annular body 11 and can be formed as an integral part of the annular body 11. The cover 12 is rigidly connected to the annular body 11.

A central cylindrical portion extends from the disc member 15 and is in an embodiment and integral part of the annular body 11. The central cylindrical portion serves as a shaft for a cylindrical part 22. The cylindrical part 22 moves axially in unison with the annular body 11 and is rotatably suspended from the annular body 11. The cylindrical part 22 is provided with a closing member 29. The closing member 29 is configured to be able sealingly close the axial inlet opening 9. Hereto, the closing member 29 is advantageously the provided with an O-ring. The closing member 29 essentially consists of a cylindrical body that sealingly fits in the circular outline of the axial inlet opening 9.

The cylindrical part 22 can move axially relative to the valve body 2. However, the cylindrical part 22 it is prevented from a rotational movement relative to the valve body 2.

Thus, the annular body 11 and the cylindrical part 22 form together an axially movable unit 10. Figs. 7 and 8 show the unit 10 in detail. Fig. 10 shows the axially movable unit 10 in a position where the closing member 29 does not close the axial inlet opening 9 and Fig. 11 shows the axially movable unit 10 in a position where the closing member 29 sealingly closes the inlet opening 9. Thus, in the position shown in Fig. 11 the control valve is completely closed and does not have any leakage.

The unit 10 is biased to the open position by a helical spring 32. The unit 10 can be moved against the bias of the helical spring 32 by applying force to the activator 6 (e.g. by using an actuator). The force of the activator 6 is transmitted to the cover 12 of the unit 10 by a central shaft 8. The central shaft 8 is sealed by an O-ring against an insert 37.

The cylindrical part 22 supports a plate member 25. The plate member 25 is urged onto the disc member 15 by the helical spring 32. Thus, the side furthest from the inlet opening 9 of the plate member 25 is pressed onto the side closest to the inlet opening 9 of the disc shaped member

15. The plate member 25 is provided with at least one second regulation opening 24 for interacting with the first regulation opening 26. One side of the plate member 25 is in contact with the side of said disk shaped element 25 closest to said inlet opening 9. The plate element 25 is arranged to move axially in unison with the annular body 11 and the plate element 25 is rotationally immovable relative to the cylindrical portion 4 of the valve body 2. Rotation of the annular body eleven relative to the valve body 2 and thus relative to the plate member 25 establishes a greater or smaller overlap between the at least one first regulation opening 26 and the at least one second regulation opening 24.

Thus, greater or smaller overlap may be established between the at least one first regulation opening 26 and the at least one second regulation opening 24 by the rotation of the annular body 11 relative to the valve body 2. The size of the overlap can be used to determine the flow area of the adjustable opening through which the liquid that flows through the control valve one needs to pass. The differential pressure regulation function ensures that the pressure differential over the adjustable size opening is constant, thereby allowing very precise control of the flow.

Fig. 10 illustrates the areas in the valve where the first pressure P1 resides and the area in the valve where the second pressure P2 resides. Pressure P1 resides in the inlet area of the control valve. Pressure P2 is established through a pressure drop over the adjustable size opening and acts on the same side of the rolling diaphragm 16 as the helical spring 20. Pressure P3 is the pressure at the outlet 7 of the control valve 1 and is established by a pressure drop from the second pressure P2 over the exit openings 18. The threat for coupling the control valve 1 shown in Figs. 10 to 15 to an actuator is than external threat, whereas the threat for coupling the control valve 1 shown in Figs. 1 to 9 is an internal threat. Both types of threat and other coupling means can be used interchangeably for coupling actuator to the control valve

1.

Pressure P1 needs to be communicated to the side of the rolling diaphragm 16 furthest from the axial inlet opening 9. At least one pressure communication channel 28 is provided in the annular body 11 for communicating the first pressure P1 from a position on the axial extremity of the annular body 11 closest to the longitudinal end of the control valve 1 with the inlet opening 9 to a position on the other side of the rolling diaphragm 16. Hereto, at least one pressure communication channel 28 extends substantially axially through the annular body 11. In an embodiment, a pressure communication channel 28 extends axially between two axially extending exit openings 18. The at least one pressure communication channel 28 opens to the axial extremity of the annular body 11 closest to the inlet opening 9, i.e. to the chamber with the first pressure P1.

Thus, liquid can flow from the chamber with the first pressure P1 in the cylindrical portion of 4 and from there into the pressure communication channels 28, regardless of the relative rotational position between the plate member 25 and the annular body 11 and via the communication channel 28 to the opposite side of the rolling diaphragm 16, without the need for any opening in the rolling diaphragm 16. Thus, the rolling diaphragm 16 can be made from a single piece of material without any through going hole in it.

A handle 5 for manual adjustment of the rotational position of the annular body 11 protrudes through a circumferentially extending slot in the valve body 2. The handle 5 engages an interconnecting cylindrical member 3 that is arranged to rotatably move relative to the valve body 2. The interconnecting cylindrical member 3 is sealed against an insert 37 by means of O-rings. The insert 37 is statically disposed in the valve body 2 and sealed against the valve body 2 by an O-ring. The insert 37 is provided with a central bore through which the interconnecting cylindrical member 3 passes with a sealing fit provided by O-rings. This allows the interconnecting cylindrical member 3 to move rotationally relative to the valve body 2 in a sealing manner. The interconnecting cylindrical member 3 is connected to a cover 12 of the annular body 11. The cover 12 is rigidly connected to the annular body 11. Rotational movement of the handle 5 is transmitted to the annular body 11 via the interconnecting cylindrical member 3 and the cover 12. The position of the handle 5 is secured against unintentional change of position by a locking member 34.

The central shaft 8 extends through a central bore in the interconnecting cylindric member 3. The central shaft 8 extends axially between the activator 6 and the cover 12 and thus transmits axial force from the activator to the annular body 11. This axial force, that can originate form an electric or other type actuator urges the annular body 11 axially in the direction of the axial inlet opening 9 against the action of the helical spring 32. When sufficient axial force is applied to the activator 6, the annular body 11 together with the cylindrical part 22 with its closing member 29 are pushed towards the axial inlet opening 9 until the closing member 9 engages the inlet opening, thereby closing the inlet opening sealingly. This closed position of the control valve 1 is illustrated in Fig 11. The open position of the control valve 1 where no force is applied to the activator 6 is shown in Fig. 10. The actuator can therefore be a simple on/off type linear actuator that either applies a force or does not, although a more sophisticated type of linear actuator that can be commanded to move to a desired position can also be used.

When the control valve 1 is open, the size of the adjustable size opening is adjusted by rotation of the annular body 11 relative to the valve body 2 and thus relative to the plate member 25 so that the overlap between the first regulation opening 26 and the second regulation opening 24 changes.

The pressure drop from the first (inlet) pressure P1 to the second (intermediate) pressure P2 is kept constant by the rolling diaphragm 16 that finds its position under the balance of the pressures and the spring force acting on the rolling diaphragm 16. The flow though the exit openings 18 is restricted to a degree depending on the position of the rolling diaphragm 16 and causes the pressure drop from the second (intermediate) pressure P2 to the third (outlet) pressure P3.

The control valve 1 is suitable for use in a manifold 40, such as for example a manifold for a floor heating system. Hereto, the control valve 1 is installed in the manifold using the outer thread on the valve body 2 that engages corresponding thread in the manifold 40. The manifold 40 is preferably provided with fittings 42 that engage the longitudinal end of the valve body 2 with the axial inlet opening 9. Thus, the supply of the first pressure P1 can take place through a manifold 42.

In the shown embodiments, the rotational position of the annular body 11 is adjusted manually using the handle 5. However, the rotational position of the annular body 11 may in not shown embodiments be adjusted by an actuator or the like, e.g. under control from an electronic control unit.

The various aspects and implementations has been described in conjunction with various embodiments herein. However, other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed subject-matter, from a study of the drawings, the disclosure, and the appended claims. In the claims, the word comprising does not exclude other elements or steps, and the indefinite article a or an does not exclude a plurality. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measured cannot be used to advantage. The reference signs used in the claims shall not be construed as limiting the scope.

Claims

Control valve (1) for controlling liquid flow in a heating and / or cooling system, which control valve (1) comprises:

a pressure regulating arrangement configured to maintain a substantially constant differential pressure between a first pressure (P1) in the control valve (1) and a second pressure (P2) in the control valve (1), the pressure regulating arrangement comprising a movable throttle element (16 ), which at the first pressure (P1) is forced to increase the flow resistance imposed by the pressure regulating arrangement, and which at an elastic element (20) and at the second pressure (P2) is forced to reduce the flow resistance imposed by the pressure regulating arrangement, wherein the movable throttle member comprises a roller diaphragm (16) interacting with a plurality of exit openings (18), the roller diaphragm (16) having a circular periphery attached to an annular body (11) disposed in the control valve (1). ), the plurality of outlet openings (18) being formed radially through the annular body (11), characterized by at least one pressure connection channel (28) extending in the annular body (11) for connecting the first pressure (P1) from a first location in the control valve (1) on one axial side of the roller diaphragm

20 5

25 6 (16) to another location in the control valve (1) on the other axial side of the roller diaphragm (16).

Control valve (1) according to claim 1, characterized in that the pressure connection channel (28) is opened towards two axially separated openings in the annular body (11).

Control valve (1) according to claim 1 or 2, characterized in that the outlet openings (18) are elongate openings extending axially and wherein the pressure connection channel (28) extends axially between two outlet openings (18) extending axially.

Control valve (1) according to claim 3, characterized in that it comprises a plurality of pressure connection channels (28), each pressure connection channel (28) of the plurality extending between two outlet openings (18) extending axially.

Control valve (1) according to any one of claims 1 to 4, characterized in that the plurality of outlet openings (43) are circumferentially distributed over the periphery of the annular body (11).

Control valve (1) according to any one of claims 1 to 5, characterized in that the roller diaphragm (16) comprises a continuous material body.

Control valve (1) according to claim 6, characterized in that the roller diaphragm has no through-openings.

Control valve (1) according to any one of claims 1 to 7, characterized in that it further comprises a flow area regulator for regulating a control flow area for at least one variable-sized inlet opening, through which the liquid flow through the control valve (1) from an inlet opening (9) to an exit opening (7) must pass.

Control valve (1) according to claim 8, characterized in that the arrangement for maintaining a constant differential pressure maintains a constant differential pressure over the opening of adjustable size.

Control valve (1) according to any one of the claims

1 to 9, characterized in that it comprises an elongate, preferably rotationally symmetrical, valve body (2, 4) with opposite first and second longitudinal ends, wherein it

15 first end is provided with a closable entrance opening (9).

Control valve (1) according to any one of claims 1 to 10, characterized in that the annular body

20 (11) is slidably located in a cylindrical part (4) of the valve housing (2) to enable axial movement and rotational movement of the annular body (11) relative to the valve housing (2).