DK201400014A1 - A control valve - Google Patents

Abstract

A control valve (1) for centrolling liquid flow in a heating and/or cooling installation under command from an actuator. The control valve (1) comprises a flow regulator with a first annular valve member (20) and a second annular valve member (40) that have an axial overlap. The first valve member (20) is rotatable relative to the second valve member manually (40). The axially overlapping portions of the valve members (20,40) define an inlet opening (52, 53) with a variable circumferential extent. At least the first valve member (20) or the second valve member (40) are provided with an oblong opening (25,41,42) that is used to define the inlet opening (52,53), the oblong opening (25,41,42) having a circumferential extent that is larger than its axial extent. The valve member (20,40), in which the oblong opening (25,41,42) is disposed, is provided with one or more reinforcing ribs ( 13, 35, 3 9) extending across the oblong opening. A third valve member (24) is axially displaceable by the actuator relative to the inlet opening (52, 53) and de fines at least one control edge (26, 27) associated with the inlet opening (52, 53). Rotation of the first valve member (20) relative to the second valve member (40) changes the circumferential extent of the inlet opening (52, 53) . Axial displacement of the third valve member (24) changes the axial extent of the through-flow area of the inlet opening (52,53). A differential pressure regulator is provided downstream of the flow regulator.

Description

A CONTROL VALVE

The present invention relates to a control valve for controlling liquid flow in a heating and / or cooling installation, in particular a control valve for controlling liquid flow under command from an actuator within a range defined by a manually preset maximum.

BACKGROUND ART WO 2013/007633 discloses a control valve for controlling liquid flow in a heating and / or cooling installation under command from an actuator. The control valve comprises a flow regulator with two annular valve members that have an axial overlap. The one valve member is manually rotatable relative to the second valve member. The axially overlapping portions of the valve members define an inlet opening with a variable circumferential extent. A third valve member is axially displaceable relative to the inlet opening and defines a control edge associated with the inlet opening. Rotation of the first valve member relative to the second valve member changes the circumferential extent of the opening, in order to manually preset a maximum through-flow area. Axial displacement of the third valve member changes the axial extent of the through-flow area of the inlet opening, in order to regulate the through-flow area within a range limited by the preset maximum. A differential pressure regulator is provided downstream of the flow regulator, and it regulates the differential pressure across the inlet opening.

The control valve disclosed in W) 2013/0076: 13 has the advantage that it. allows for an independent valve member to control the circumferential extent and for another independent valve member to control the axial extent of the effective through-flow area of the flow regulator.

Thus, the axial movement (stroke) of the valve remains the same independent of the circumferential extent of the effective through-flow area. The control valve automatically adjusts itself to any flow area if it is adjusted manually or by actuator, axially or circumferentially. When the operator presets the valve according to a maximum design flow, the stroke of the control valve remains the same.

However, the control valve disclosed in WO: 2013/007633 has the disadvantage that the large circumferential extent of the through-flow openings in the valve members of 180 0 weakens the valve members in which the openings are formed and therefore relatively stable valve member material and relatively high wall thickness needs to be used for these valve members,

SUMMARY

It is an object of the invention. · To overcome or at least reduce the problems and / or drawbacks associated with the prior art control valves.

This object is achieved by providing a control valve for controlling liquid flow in a heating and / or cooling installation under command of an actuator, the control valve comprising a valve housing with an inlet and an outlet, a flow regulator comprising a first valve member having an annular or penannular portion with a certain axial extent, a second valve .member having an ar: zero or peri annular portion with a certain axial extent, the annular or penannular portion of the first valve member having an. axial overlap with the annular or penannular portion of the second valve member, the first valve member being manually rotatable relative to the second valve member, the axially overlapping annular or penannular portions of the first valve member and of the second valve member defining at least one inlet opening with a variable circumferential extent in fluid communication with the inlet, at least the first valve member and / or the second valve member being provided with at least one oblong opening used to define said at least one inlet opening, the at at least one oblong opening having a circumferential extent larger than its axial extent, the valve member in which the at least one oblong opening is disposed is provided with one or more reinforcing ribs extending across the at least one oblong opening, a third valve member with an annular, penannular or cylindrical portion with a certain axial extent, the third valve member being axially displaceable, preferably by the actuator, relative to the inlet opening, the third valve member defining a first control edge associated with said at least one inlet opening, wherein rotation of the first valve member relative to the second valve member changes the circumferential extent of the inlet opening for manually presetting a maximum through-flow area of the inlet opening, and whereby axial displacement of the third valve member changes the axial extent of the through-flow area of the inlet opening to regulate the through-flow area of the inlet opening within a range limited by the preset maximum, and a differential pressure regulator downstream of the flow regulator with an outlet of the differential pressure regulator being in fluid connection. with the outlet.

By providing a .reinforcing rib.across the oblong opening the stability of the valve member concerned is significantly improved.

In one embodiment, the one or more reinforcing ribs extend axially across the oblong opening.

In an embodiment the one or more reinforcing ribs are integrally formed in the first and / or second valve member concerned,

In an embodiment the one or more reinforcing ribs have a wall thickness in the radial direction which is essentially identical to the wall thickness of the material around the oblong opening of the first and / or second valve member concerned.

In one embodiment, the one or more reinforcing ribs have a wall thickness in the circumferential direction that is significantly smaller than the circumferential extent of the oblong opening.

In an embodiment the head nut or the end cap can be combined with the housing 2 in a single part.

In an embodiment the seals and seal securing parts are combined with the second valve member m a single part made of two different materials using technology such as muIti-compo nent mol d ing,.

In an embodiment the first vslv-e member and the valve stem is a single part. In another it is two separate parts,

In one embodiment, 0-ri.ng seals the end cap to the valve housing and the bulge on the diaphragm seals the end cap to the second valve member - In another embodiment, the bulge on the diaphragm: seals the end cap to the valve housing. In another embodiment where the end cap is combined with the housing in. a. Single part, the bulge on the diaphragm seals one end of the second valve member to. the valve housing,

Further objects, features, advantages and properties of the control valve according to the disclosure will become apparent from the detailed description.

LETTER DESCRIPTION OF THE DRAW I. MGS

In the following detailed portion of the description, the invention will be explained in more detail with reference to the exemplary embodiments shown in the drawings, in. which:

Fig. 1 is a side view of a control valve according to example embodiment #

FIG. 2 is a top view of the control valve of FIG. 1

FIG. 3a is a side view of the control valve of FIG. 1 with an electronic actuator fitted thereto,

Fig. 3b is a view of the control valve of Fig. I with a key fitted thereto,

FIG. 4 is an exploded view of the control valve of FIG. X,

FIG. 5 is a sectional view of the control valve of Fig. 1,

FIG. 6 is a cross ~ .secti.onal view of the control valve of

FIG. 7 is an exploded view of an example embodiment of the first, second and third valve members of the valve of

FIG. 8a is a side view of the valve members of FIG. 7 in assembled form in a first position with a rotatable valve member in a fully closed position and illustrated together with a fixed angular scale and rotatable indicator,

FIG. 8b, is the same view as FIG. 8a, with the rotatable valve member in a halfway closed position and the axially displaceable valve member also in a halfway closed position and illustrated together with the fixed angular scale and rotatable indicator,

FIG. 8c, is the same view as FIG. 8a, with the rotatable valve member in a fully open position and the axially displaceable valve member also in a fully open position and illustrated together with the fixed angular scale and rotatable indicator,

FIG. 9 is an exploded view of the valve members of another example embodiment of the control valve shown in Fig. 1.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Example embodiments of the invention will now be described with reference to the drawing figures, in which like numerals refer to like parts throughout.

The control valve 1 is an example embodiment of a regulator valve which includes differential pressure regulating facilities and flow area regulating facilities. Preferably the control valve is provided with means for manually presetting a maximum flow through area and with means for automatically adjusting the flow through area within the preset maximum. The flow regulation is tightly connected, with the differential. pressure regulation. Thus # the actual regulation in the parts referred to as the flow regulation facilities or the flow regulator is' '' only '' a regulation of the size of the through-flow area. The combination of the carefully controlled through-flow area and the differential pressure across the # .results in the actual flow regulation.

Figs. 1 to 7 and 8a-8c illustrate an example embodiment of a control valve 1 for use in a heating or cooling plant. In this embodiment, the control valve 1 has a valve housing 2, The valve housing 2 is in an embodiment made of a suitable metal alloy # such as eg, bronze (including gunmetal), brass {including corrosion-resistant and dezincification resistant brass # DZR or DR} # ductile iron or steel {including stainless steel) and can be manufactured by a suitable molding technique such as hot pressing # die casting or forging. The valve housing 2 is provided with an inlet 3 and an outlet 4. The liquid flows into the inlet 3 and out of the outlet 4 as indicated by the arrows in Fig. 5, Both the inlet 3 and outlet 4 are provided with internal or external (not shown) threads or other connection facilities # such as press end connections # for connection to pipes of a heating or cooling plant.

The valve housing 2 is a hollow and essentially cylindrical body with open axial ends and with the inlet 3 and outlet 4 on opposite sides of the cylindrical body and opening to the interior 8 of the hollow in the valve housing, The. axial ends of the vaive: housing 2 are closed by a bead nut 6 which is fitted to the upper (upper as depicted in Fig. 1) axial end and an end cap 7 secured to. the opposite axial end. Both the head nut 6 and the end cap 7 are secured to the housing (including possible fastening features such as locking screws 17.49 ox that the inside of the housing, and the outside of the head nut 6 and the end cap, respectively 7 is threaded), an 0-ring 21 seals the head nut 6 to the valve housing 2 and an 0-ring Si seals the end cap 7 to the valve housing 2 and a bulge on the diaphragm seals the end cap 7 to the second valve member 40, which is sealed to the housing by O-ring 44,

The valve housing 2 can be provided with P / T plugs .1.8., 19, for pressure and / or temperature sensors of the same or for de-aeration equipment.

The head-nut 6 is provided with a fastening feature (including options of a threaded collar 14 or a snap fit locking mechanism (not shown) 5 that allows an actuator 60 (shown in Fig, 3) to be attached to the top of the Control valve X, The actuator 60 is preferably a thermal or electrical actuator, A rotatable valve stem 12 protrudes from the inner parts of the valve. The rotatable valve stem 12 can be rotated about the central axis X of the control valve 1, embodiment of the valve stem 12 is an integral part of the first valve member 20 and in an embodiment, the valve stem 12 and the first valve member 20 are part of a single molded item, A .marker 15 is secured to the rotatable valve stem 12 and rotates in unison therewith.The valve is provided with a fixed angular scale 16 to indicate the angular position · of the marker 15 and thereby of the valve stem 12 and the second valve member 20.

An axially displaceable pin 10 is received concentrically, in an axial bore in the valve stem 12. The actuator 60 acts on the pin 10.

Figs. 4 to? and 8a-8c show the internal components of the control valve 1 in greater detail. A valve insert comprises the first valve member 20, a second valve member 40 and a third valve member 24 is inserted into the hollow Interior 8 of the valve housing 2. In an embodiment, the valve members 20,24,40 are made mainly of a plastic material (polymer material). In an embodiment the first valve member 20 is arranged to be rotatable .00.13.1: 1¾¾ to the second valve member 40 and the housing 2. In an embodiment the second valve member 40 is stationary relative to the housing 2- The first valve member 20 has an essentially frustoconical shaped portion and an essentially annular shaped portion. The valve stem 12 is operatively connected to the frustoconical shaped portion so that the first valve member 20 rotates in unison with the valve stem 12. The annular portion of the first valve member 20 has a certain axial extent and this portion is provided with a preferably oblong through-flow opening 25 with a circumferential, extent larger than its axial extent. 0-rings 23 seal valve stem. 12 to the head nut 6. The top of the frustoconical portion of the first valve member 20 abuts with the inner side of the head nut 6. The pin 10 extends through the stem 12 into the upper (upper as in Fig. 4/5 } part of the first valve member 20, An O-ring 2'2. Seals the pin 10. to the upper part of the first valve member 20, the lower {lower as in Fig, 4} extremity of the pin 10 engages the upper extremity of a pin 31 projecting upwardly (upwardly as in Fig. 4} from the third (axially displaceable) valve member: 24, Ά preferably plastic material. (polymer) locking part 28 is received in a recess in the rotatable first valve member 20, The locking part 28 has a through-going boro with an upper opening slightly smaller in diameter than the rest of the through-going bore. The lower extremity of the pin 10 is received in the through-going bore and is provided with a flange that prevents the lower extremity of pin 10 from leaving the thoroughbore.

The upwardly projecting pin 31 of the third valve member 24 is received in the through bore in the locking part 28 with the upper extremity of the pin 31 engaging the flange provided at the lower extremity of the pin 10,

The third valve member 24 is received axially displaceable within the upper portion, of the hollow second valve member 40. The second valve 40 member has an essentially annular body, i, e. like a hollow cylinder. The upper portion of the valve member 40 is received within the annular portion of the first valve member 20, Thus, an annular portion of the second valve member 40 has an axial overlap with the annular portion of the first valve member 20, the overlapping portions. of the first and second valve members 20, 40 can be penannulax {forming an almost complete ring) instead of annular. A helical wire spring 34 is disposed between the third valve member 24 and the second valve member 40. Hereto, the second: valve member 40 - is provided with a recess at its upper end, in which a portion of. the. helical spring is received. The helical wire spring 34 urges the third valve member 24 upwards towards the pin 10 and the actuator SO,

An o-ring 36 seals the second valve member 40 to the inner wail of the valve housing 2 for dividing the valve housing 2 into an inlet part with a fluid pressure FI corresponding to the pressure at the inlet 3 and an outlet part with a pressure P3 corresponding to the pressure at the outlet 4. A Pressure: communication channel 5 communicates the pressure PI at the inlet 3 to the bottom end of the valve housing 2,

Two seal securing parts 37 secure two seals 38 to the top of second valve member 40 to enable a perfect seal between second valve member 40 (and thus housing 2) and third valve member 24 controlled by actuator 60. This enables actuator 60 to close valve 1 completely so that no leakage can occur between the inlet 3 (PI) on one side and the middle part 8 (P2) and outlet 4 (P3) on the other side. In an embodiment P2, the pressure is downstream of the arrangement for adjusting the flow area and upstream of the arrangement for the differential pressure regulation.

An axially displaceable diaphragm guide 46 has a hollow upwardly projecting stem in which a downwardly projecting guiding shaft 50 of the second valve member 40 is received. The diaphragm guide 46 supports and guides a diaphragm 4 "and the diaphragm 47 is secured to the diaphragm guide 46 by a snap ring 48, A helical wire spring 45 is disposed between the second valve member 40 and the diaphragm guide 46 to bias the diaphragm guide 46 in. downward direction as a countermeasure to .the force respectively from Pi, -which influences the diaphragm 4? and diaphragm guide 4 6 in an upward direction and from P2, which. influences the diaphragm 4 7 and diaphragm, guide 46 The second valve member 40 is provided with a plurality of exit openings 43 which are distributed around the circumference of the second valve member 40 at a height which corresponds approximately to the length of the diaphragm 47, Thus, the arrangement including the diaphragm 47 and the exit openings 43 maintain a constant differential pressure between the inlet pressure PI and the intermediate pressure P2.

The diaphragm 4 7 closes the exit openings 4 3 to greater or lesser extent. The exit openings 43 are elongated openings with their greatest extent in the axial direction. A higher (higher than eg in Figs. 4 and 5} position of the diaphragm 47 and diaphragm guide 46 results in a smaller extent of the elongated exit openings 43 being open and a lower position of the diaphragm 47 and diaphragm guide 46 results in a larger extent of the exit openings 43 being open.

The portion of the rotatable stem 12 protruding from the valve housing-2 is configured to be engaged by a detachable handle or key 70. Hereto, the upper portion of the valve stem 12 is provided with a noncircular cross-section, in an embodiment this is a squared cross-sectional shape that matches a key 70 with a recess with a squared cross-sectional shape.

Figs. 7 and 8a ~ 8c disclose the first valve member 20, second valve member 40 and the third valve member 24 in greater detail and explain their operation.

As shown in Fig. 7, the first rotatable valve member 20 is provided with an oblong first through-flow opening 25 in its annular or penannular part. The circumferential extent of the first through-flow opening 25 is in this example embodiment, approximately 180 ° but could be smaller in other embodiments. A reinforcing rib 35 extends across the first through-flow opening 25 in order to reinforce and stabilize the first valve member 20. In the shown embodiment, the reinforcing rib 35 is placed in the middle of the circumferential extent of the first through-flow opening. 25, but it is understood that the reinforcing rib 35 does not have to act in the middle of the circumferential extent of the through-flow opening and it is understood that there may be more than one reinforcing rib 35. Preferably, the reinforcing rib or ribs 35 extend axially across the through-flow opening 25, but it is understood that the reinforcing rib or ribs 35 can also extend across the first through-flow opening 25 at an angle to the axial direction. The reinforcing rib or ribs 35 have, in an embodiment, the same thickness in the radial direction as the wall thickness of the material around the first through-flow opening 25. The circumferential extent or width of the reinforcing rib or ribs 35 is significantly smaller than the circumferential extent of the first through-flow opening 25.

The first valve member 20 is further provided with a semi-annular recess 29 which is achieved by a reduced axial extent section of the annular portion. The semi-annular recess 29 has a circumferential extent of approximately 180 ° but could in other embodiments have a smaller circumferential extent. The semi-annular recess 29 is axially offset to the first through-flow opening 25 so that there is no axial overlap between the first through-flow opening 25 and the semi-annular recess 29.

The third axially displaceable valve member 24 can be provided with radial reinforcement ribs 33 which attach to a central shaft 30 and with a first semi-annular control edge 26 and a second semi-annular control edge 27 which is axially displaced relative to the first control edge 26 to a degree corresponding to the axial offset between the first through-flow opening 25 and the recess 29. This is achieved by the axial extent of the annular or penannular portion of the third valve member 24 having a larger axial extent than the axial extent of a semi-annular portion of the third valve member 24,

The stationary second valve member 40 is provided with an oblong first through-flow opening 41 and oblong second through-flow opening 42 which is axially offset relative to the first through-flow opening 41 to a degree corresponding to the axial offset between the first through-flow opening 25 and the recess 29.

The circumferential extent of the first through-flow opening 41 and of the second through-flow opening 42 in this example embodiment is almost 180s but could be smaller in other embodiments. The first through-flow opening 41 is provided with a reinforcing rib 39 and the second through-opening 42 is provided with a reinforcing rib 13. In the shown embodiment, the reinforcing rib 13,39 is placed in the middle of the circumferential extent of the first or second through-flow opening 42.41, but it is understood that the reinforcing rib 13.39 does not have to be in. the siid-dl © of the circumferential extent of the: through-flow opening and it is understood that there can be more than one reinforcing ribs $ 13.3. Preferably, the reinforcing rib or ribs 13,33 extend axially across the through-flow opening 42,41, but if it is understood that the reinforcing rib or ribs 13,39 can also extend across the first through-flow opening 42,41: at an angle to the axial direction. The reinforcing rib or ribs 13,39 have in an embodiment the same thickness in the radial direction as the wall thickness of the material around the first through-flow opening 42,41. The circumferential extent or width of the reinforcing rib or ribs 13,39 is significantly smaller than the circumferential extent of the first through-flow opening 42,41,

The first through-flow opening 25 in the first valve member 20 and the first through-flow opening 41 in the second valve member 40 overlap completely in the axial direction and have a substantially identical axial extent. In an embodiment, the extent of the openings in the {rotatable} first valve member 20 is slightly larger in the axial direction than the corresponding extent of the openings of the second valve member 40 to adjust for a possible slightly imperfect axial alignment, e, g The same applies to recess 29 in the first valve member 20 and the second through-flow opening 42 in the second valve member 40. The circumferential extent of the first through-flow opening 25 in the first valve member 20 is substantially identical to the circumferential extent of the first through-flow opening 41. In the second valve member, the circumferential extent of recess 29 is identical to the circumferential extent of the second through-flow opening 42. the openings in the {rotatable} first 'valve member 20 is slightly larger than the corresponding extent of the openings of the second valve member 40 to allow the full effect of the openin g area of the second valve member 40.

When the rotational position of the first valve member 20 relative to the second valve member 40 is shown in FIG. 8a there is no overlap between the first through-flow opening 25 in the first valve member 20 and the first through -flow opening 41 in the second valve member 10. In this rotational position of the first valve member 20 relative to the second valve member 40 there is no overlap between recess 29 in the first valve member 20 and the second through-flow opening 42 in the second valve member 4 0 either. Thus, the control valve 1 is essentially closed for through-flow and this is indicated by the rotatable marker 15 indicating position "1" in the fixed angular scale 16 «

When the rotational position of the first valve member 20 relative to the second valve member 40 is shown in FIG. 8b there is an overlap between the first through-flow opening 25 in the first valve member 20 and the first through-flow opening 41 in the second valve member 40 which results in a first inlet opening 52 with a circumferential extent equal to half the circumferential extent of the first through-flow opening 25, i, e. approximately 90 ° In this rotational position of the first valve member 20 relative to the second valve member 40 there is an overlap between the recess 29 in the first valve member 20 and the second through-flow opening 42 in the second valve member 40 which results in a second inlet opening 52 having a circumferential extent equal to half the circumferential extent of the recess 29 * ie, a pp rox ixa ately 9 00. • In fig. 8b it can also be seen. . that the third valve. member 24 assumes a position where the first, control edge 26 obscures approximately half of the axial extent of the first inlet opening 52 which is defined by the overlap between the first through-flow opening 25 and the first through-flow opening 41, simultaneously, the second control edge 27 obscures approximately half of the axial extent of the second inlet opening 52 which is defined by the overlap between the recess 29 and the second through-flow opening 42,

The axial position of the third valve member 24 is completely independent, from the rotational position of the first valve member 20 and Is positioned in Fig. 8b: that half of tire inlet openings created by the first .and second valve members 20, 40 is obstructed merely for illustration purposes and it is understood that the third valve member 24 could, under command of actuator 60, assume any axial position in the range between a position that does not obscure all the inlet openings created by the first and second valve member 20.40 and a position where the third valve member 24 completely obscures the inlets created by the first and second valve members 20.40 and furthermore reaches the seals 38 in order to completely close off all flow.

Thus, the control valve 1 is half-closed, for through-flow and this is indicated by the rotatable marker 15 indicating position "3" in the fixed angular scale 16, i, e, the maximum flow through the control valve 1 is determined at two inlet openings that each assumed half of their maximum through-flow area,

When the rotational position of the first valve member 20 relative to the second valve member 40 is shown in Fig, there is a complete overlap between the first through-flow opening 25 in the first valve member 20 and the first through-flow opening 41 in the second valve member 40, This results in the first inlet Opening 52 having a circumferential extent equal to the circumferential extent of the first through-flow opening 25, due., Approximately 180 °, in this rotational position of the first valve member 20 relative to the second valve member 40 there is a complete overlap between the recess 29 in the first valve member 20 and the second through-flow opening 42 in the second valve member 40. This results in a second inlet opening 53 with a circumferential extent equal to the circumferential extent of recess 29, 1., e, approximately 180

In Fig. 8c, the third valve member 24 is for illustration purposes positioned such that it does not obscure the inlet openings created by the overlap between the through-flow openings in this first and second valve members 20, .4 0, i.e. the first inlet opening 52 and the second inlet opening 53 have their maximum flow through area.

In this rotational position of the first valve member 20, the inlet openings formed by the overlap in the through-flow openings in the first and second valve members 20, 40 are preset to their maxi muxs possible flow-through area. This is reflected by the rotatable marker IS indicating position "S"% i.e. the fully open position with the control valve 1 being set to its highest maximum flow range,

The valve 2 is in an embodiment a; self-balancing dynamic flow control valve that is pressure independent # with an :. actuator 60 which is controlled by an input signal or by ambient temperature, the amount of liquid flowing through the control valve 1 is determined by an adjustable throttling element # which is in an embodiment formed as an adjustable orifice formed by the inlets created by the overlap between the first and second valve members 20 # 40,

The angular position of the rotatable first valve member 20 determines the maximum flow area of the adjustable orifice as formed by the two inlet openings. The position of the rotatable valve member 20 and thus of the valve stem 12 has to be set accurately so that the operator knows exactly the maximum flow for the chosen setting.

The position of an axially displaceable shaft or pin 10 which is concentric with the valve stem 12 and protrudes from the valve stem 12 determines the axial flow area of the throttling element / adjustable orifice in the control valve 1 between a minimum value and the maximum set value determined by the position of the rotatable valve member .2.0.,

The axially displaceable pin 10 is operably connected to the actuator 60 so that the position of the axially displaceable pin 10 and the third valve member can be controlled with a control signal to the actuator 6Q # or by ambient temperature:.

The maximum flow area is manually set by an operator when the .actuator 60 is dismounted from the control valve 1 and the valve stem: 12 can be accessed. The shape and site of the ..valve stem 12 and the .torque required to rotate the valve stem 1.2 is such that it is not possible for an operator to adjust the position of the rotatable valve member 20 without the use of a suitable tool. For this purpose a detachable handle or key? 0 is provided. The detachable key 70 is detachably coupled to the valve stem 12 and the key 70 provides an operator with enough leverage to adjust the position of the rotatable valve member 20,

In operation, fluid, such as cold, or hot water, arrives at the inlet 3 with a pressure level PI. This water flows through the two inlet openings defined by the overlap between the through-flow openings 25,41,42 and recess 29 into the interior 8 of the control valve 1, the two inlet openings act as a restriction / orifice and therefore the pressure P2 in the interior 8 of the control valve 1 is lower than pressure Pi, The pressure of the liquid in the interior 8 of the control valve urges the diaphragm 47 downwards, together with the helical wire spring 45, Pressure PI is communicated via the pressure communication channel 5 to the opposite side of the diaphragm 47 and urges the diaphragm 47 upwards. The balance of these forces determines the position of the diaphragm 47 and thereby the differential pressure across the inlet openings / oriflee. Since the diaphragm. 47 and the exit openings 43 act as a restriction to the flew pressure P3 in outlet 4 is lower than pressure R2,

Fig. 10 shows the valve members of another example embodiment of the control valve 1 which is essentially identical to the control valve described above, except that the rotatable valve member 20 is provided with a single flow- through opening 25 provided with a reinforcing rib 35 .and the second valve member 4.0 is provided with a single flow-through opening 41 provided · with a reinforcing rib 39. The axially displaceable third valve member 24 is provided with a single control edge 26. The circumferential The extent of the single flow-through openings £ 5 and 41 is at most 180 ° The reinforcement rib 35 stabilizes and reinforces the first valve member 20 and the reinforcement rib 39 in the second valve member 40 against the considerable forces acting on the valve members during operation of the control, valve 1 due to the pressure differences acting on these valve members. There can be more than one reinforcing rib 35, 39 for each flow-through openings 25, 41. The operation of the control valve 1 of this embodiment is essentially identical to the operation of the control valve 1 described above,

In the shown embodiment, the angular range of the valve stem 12 and the rotatable valve member is approximately 180 ^. However, it is noted that the teaching of this invention may also be applied to valves having a much smaller range of rotation for the rotatable valve adjustment member, such as approximately 90 °. In an embodiment the total circumferential extent of the openings are larger than 360% however this will prevent use with (relatively) small flows.

As such, those skilled in the art will appreciate that the conception upon which this invention is .based may readily be utilized as a basis for designing other structures, methods and systems for carrying out the various purposes of the present invention. It is important, therefore, that the claims should be considered. including such equivalent constructions insofar ·· as they .: do not depart from the scope of the present invention.

The term "comprising" as used in the claims does not exclude other elements or steps. The term "a" or "an" as used in the claims does not exclude a plurality.

Claims (4)

1. A control valve (1} for controlling liquid flow in a heating and/or cooling installat ien under -command frotv an actuator, the control valve {1)- comprises; a valve housing (2} with an inlet. (3) and an outlet (4) ? a flow regulator comprising; a first valve member (20·) having an annular or penannular portion with a certain axial extent? a second valve member (40) having an annular or penannular portion with a certain axial ettent, the annular or penannular portion of the first valve member (20) having ah axial overlap: with the annular or penannular portion of the second val ve member (4 0), the first valve member (20) being manually rotatable relative to the second valve member (40) f the axially overlapping annular or penannular portions of the first valve member (20) and of the second valve member (40) defining at least one inlet opening (52,53) with a variable circumferential extent in fluid communication w i t h t h e i. n 1 a t (3), at least the first valve member (20) and/or or the second valve member (40) being provided with at least one oblong opening (25,41,,42) that is used to define said at least one inlet opening (52.53) , the at least one oblong . opening .· . . . (25,41,42) having a circumferential extent that is larger than its axial extent, the valve member (20, 40) , in. which the at least one oblong opening (25,41,42). is disposed, is provided with one or more reinforcing ribs (13,35,39) extending across the at least one oblong opening (25,41,42), a third valve member (24) with an annular, penannuiar or cylindrical portion with a: certain axial extent, the third valve member (24) being axially displaceable, preferably by the actuator, relative to the at least one inlet opening (52.53) , the third valve member (24) defining a first control edge (26) associated with said at least one inlet opening (52,53), whereby rotation, of the first, valv.e. member (.20) relative to the second valve member (40) changes the circumferential extent of the at least one inlet opening (52,53) for manually presetting a maximum through-flow area, of the at least one inlet opening (52,53), and whereby axial displacement of the third valve member (24) changes the axial extent of the through-~ilow area of the at least inlet opening (52,,531 for regulating the through-flow area of the at least inlet opening .(52,535 within a range limited by the preset maximum, and a differential pressure regulator downstream of the flow regulator with an outlet of the differential pressure regulator being in fluid connection with the Outlet (4) «

2. A control valve (1) according to claim 1, wherein the one or more reinforcing ribs (13,35,395 extend axially across the oblong opening (25,41,42), 3., A control valve (.1). according to claim 1 or 2, wherein the one or more reinforcing ribs (13, 35,39) are integrally formed in the first or second, valve member (20,40) concerned,

4, A control valve (1) according to any one of claims 1 to 3, wherein the one or more reinforcing ribs (13,35,39) have a wall thickness in the radial direction that is essentially identical to the wall thickness of the material around the oblong opening (35,39) of the first or second valve member (20,40) concerned,

5. A control valve (1) according to any one of claims 1 to 4, wherein the one or more reinforcing ribs (13,35,39) have a wall thickness in the circumferential direction that is significantly smaller than the circumferential extent of the oblong opening (25,41,425.