GB2569652A

GB2569652A - Flow control valve

Info

Publication number: GB2569652A
Application number: GB1721781.1A
Authority: GB
Inventors: Denis Janocha Marc
Original assignee: Eaton Intelligent Power Ltd
Current assignee: Eaton Intelligent Power Ltd
Priority date: 2017-12-22
Filing date: 2017-12-22
Publication date: 2019-06-26
Also published as: WO2019122462A1; GB201721781D0

Abstract

A flow control valve comprises a housing 1 forming a number of internal passages 8 and an internal cavity 2 in fluid communication with each of the internal passages 8, each of the internal passages 8 comprising an orifice 15 opening into the internal cavity 2. A flow direction block 3 is arranged in the internal cavity, the flow direction block 3 having an outer face 4 encircled by an inner face 5 of the internal cavity 2. The flow direction block 3 comprises two clearances 6, 7 extending through a portion of the flow direction block, and each of the two clearances 6, 7 is adapted to selectively connect at least three of the internal passages 8 of the housing 1 when the flow direction block 3 is rotated around a rotation axis relative to the housing 1.

Description

The invention refers to a flow control valve, comprising a housing forming a number of internal passages and an internal cavity in fluid communication with each of the internal passages, each of the internal passages comprising an orifice opening into the inner cavity; a flow direction block arranged in the internal cavity, the flow direction block having an outer face encircled by an inner face of the internal cavity, wherein the flow direction block comprises two clearances extending through a portion of the flow direction block, wherein each of the two clearances is adapted to selectively connect at least two of the internal passages of the housing when the flow direction block is rotated around a rotation axis relative to the housing.

A flow control valve, like for example a four-way valve is adapted to accommodate two inlet flows and provide two outlet flows, and can be used where it is desired to switch or alternate the fluid flows to be fed to different parts of a fluid system. By way of example, a fluid flow system might utilize different fluids and, periodically, it is desired to switch or change the fluids which are to be fed into different flow paths of the system. A single valve can switch a pair of inlets and outlets to change the relationships of the inlets and outlets.

In EP 1 811 215 B1, for example, there is disclosed a valve wherein the position of a ball closure determines the communicating relationships of the inlets and outlets. By rotating the ball closure, the inlets are selectively placed in communication with the respective outlets. The ball closure for the four-way valve includes two bores to provide two flow paths between the inlets and outlets. One of the problems with such a prior art valve is that by rotating the ball closure, the four-way valve is switched but cannot be controlled in regard of the flow through one of the flow paths, which makes an additional control valve necessary if such a flow control is desired. Modern refrig erant systems require the guidance of the refrigerant flow into different components, while at the same time allowing the evacuation of the unused components. Furthermore, architectures of refrigerant circuits require additional functionalities, specifically to guide an incoming refrigerant flow into two components at the same time, and to restrict either of these flows fully or partially.

An objective of the invention is to provide a flow control valve which fulfils this demand.

The objective is achieved by a flow control valve according to claim 1. The dependent claims refer to preferred embodiments.

The flow control valve according to the invention comprises a housing forming a number of internal passages and an internal cavity in fluid communication with each of the internal passages, each of the internal passages comprising an orifice opening into the inner cavity. A flow direction block is arranged in the internal cavity, the flow direction block having an outer face encircled by an inner face of the internal cavity, wherein the flow direction block comprises two clearances extending through a portion of the flow direction block, wherein each of the two clearances is adapted to selectively connect at least two of the internal passages of the housing when the flow direction block is rotated around a rotation axis relative to the housing, wherein the two clearances are adapted to control a flow through at least one of the two clearances by way of rotating the flow direction block.

It is understood by a person skilled in the art that the flow direction block is formed as a solid of revolution and that the internal cavity is formed complementary to provide the inner face and to allow the rotation of the flow direction block. The solid of revolution may be in the form of a sphere, a spheroid, a cylinder or a cone, for example, whereas other geometries may be applicable as well.

According to the invention, the two clearances with a segregating portion of the flow direction block arranged between the two clearances and the orifices are arranged such, that in at least one angular position of the flow direction block one of the two clearances connects at least three of the internal passages, wherein a volume of the two clearances is asymmetrical with respect to any point along the rotation axis. For example, a volume of a first clearance of the two clearances is larger than a volume of a second clearance of the two clearances, the first clearance being adapted to connect at least three of the internal passages. Generally, the two clearances differ in at least one of their geometric parameters to achieve the asymmetry. The geometry of the flow direction block thus advantageously separates the inner cavity in a way, such that an incoming flow is distributed into two flow paths in a controlled manner. In a four-way valve with four internal passages, for example, the first clearance is beneficially adapted to connect either two internal passages or three internal passages, depending on the position of the flow direction block, whereas the second clearance is adapted to either connect two adjacent internal passages or separate one internal passage while the other three internal passages are connected via the first clearance. In the latter case, for example, the incoming flow from one internal passage is divided into two flows flowing into the other two internal passages, respectively.

According to a preferred embodiment the segregating portion of the flow direction block arranged between the two clearances is offset from the rotation axis, thus rendering the volume of the two clearances asymmetrical and advantageously allowing one of the clearances to connect three internal passages.

According to a preferred embodiment and application, the flow control valve has four internal passages connected externally to a refrigerant circuit, wherein a first internal passage is connected to a compressor output, a second internal passage and a third internal passage are each connected to a separate condenser and wherein one of the clearances is adapted to connect, in at least one angular position of the flow direction block both the second internal passage and the third internal passage to the compressor output.

According to a further preferred embodiment the outer face of the segregating portion comprises a sealing sector and at least on one end a bulge sector, wherein a radius of the outer face in the sealing sector equals a radius of the inner face and wherein a distance of the outer face to the rotation axis in the bulge sector is less than the radius of the inner face. The outer face in the bulge sector is preferably curved. In particular a radius of the curved outer face in the bulge sector decreases in circumferential direction from the sealing sector towards a respective one of the two clearances.

According to yet a further preferred embodiment at least one of the orifices comprises a cutout extending a flow cross-section of said at least one orifice with respect to a cross-section of the respective internal passage. The cutout advantageously fulfils two objectives. First, the flow can be controlled easier, and second, the cutouts provide for a pressure equalization, thus protecting a sealing arrangement, which will be referred to herein later.

Preferably, the cutout extends in circumferential direction of the inner face of the internal cavity. Furthermore preferably, a width of the cutout in axial direction is less than a diameter of the respective internal passage. In particular, the width of the cutout in axial direction decreases starting from the internal passage in circumferential direction towards an end of the cutout. The cutout is for example formed as a spout.

According to yet a further preferred embodiment, the orifices of the internal passages are covered by a mesh or net, which also advantageously protects a sealing arrangement.

According to yet a further preferred embodiment, such a sealing arrangement is arranged between the outer face and the inner face, the sealing arrangement comprising at least one sealing ring, wherein the sealing ring encircles either one of the two clearances. According to a particularly preferred embodiment, the sealing arrangement comprises at least two sealing rings, wherein the two sealing rings either encircle the same one of the two clearances, or wherein both of the two clearances are each encircled by at least one sealing ring, respectively. Yet furthermore preferred, each of the two sealing rings is arranged alongside one of two boundaries of a sealing sector in the outer face of the segregating portion of the flow direction block, respectively.

The invention and advantages of the different embodiments will now be further illustrated with respect to preferred embodiments of the flow control valve as depicted in the accompanying drawings.

In the Figures

Figure 1 shows schematically a refrigerant circuit with an embodiment of the flow control valve according to the invention;

Figure 2 shows schematically different states of the embodiment of the flow control valve according to Figure 1 in a cross section;

Figure 3 shows schematically different states of a preferred embodiment of the flow control valve according to the invention in a cross section;

Figure 4 shows schematically different states of another preferred embodiment of the flow control valve according to the invention in a cross section;

Figures 5A and 5B show schematically two further preferred embodiments of the flow control valve according to the invention in a cross section;

Figure 6 shows three views of an exemplary flow direction block;

Figures 7A and 7B show schematically two variants of the embodiment of the flow control valve according to Figure 5B;

Figure 8 shows schematically a detail of the embodiment of the flow control valve according to Figure 5A in different states;

Figure 9 shows schematically the embodiment of the flow control valve according to Figure 5B in a switching procedure through different states;

Figure 10 shows schematically a further preferred embodiment of the flow control valve according to the invention in four different states.

Figure 1 sketches a simplified refrigerant circuit with an embodiment of the flow control valve according to the invention, here a 4-way valve 110. The flow control valve according to the invention is not limited to this architecture. The depicted exemplary application is described here to enhance understanding of the invention. The flow control valve 110 comprises a housing 1 with four internal passages (8, cf. Figure 2) connected to a refrigerant circuit, wherein the first or left hand internal passage 8 has a first connection 105 to an output of a compressor 100, the second or top internal passage 8 and the third or bottom internal passage 8 having second and third connections 106, 107, each connected to a condenser 101, 102. The fourth or right hand internal passage 8 has a connection 108 connecting it to a suction line towards a suction side of the compressor 100. The four internal passages 8 will further also be referred to as left hand, right hand, top and bottom internal passages 8, which only refers to the respective illustration and does not mean any restriction in terms of geometric forms of the valve. Regarding the application of Figure 1, the internal passages 8 are connected as described before, which also applies for the following embodiments described with respect to the following Figures. The lines represent fluid connections. The single break in the line from the third connection 107 to the second condenser 102 represents a fluid connection, which is not connected to the crossing line.

In the application a refrigerant flow coming from the compressor 100 is guided into one of two condensers 101, 102, which may e.g. be an inner condenser for a heat pump or for battery tempering in a hybrid electric vehicle, or a simple outer condenser. In some circumstances it may be required to supply both condensers 101, 102 at the same time, instead of just one. Additionally, it is beneficial to control the amount of heat that is supplied to the condensers 101, 102, i.e. the amount of refrigerant, rather than only choosing between an on- and an off-state. After flowing through the condensers 101, 102 the refrigerant passes an expansion valve 103, then an evaporator 104, and finally flows back to the compressor 100. A fourth connection 108 of the 4-way-valve 110 may be used, when only one condenser 101, 102 is active. If, for example, all the flow from the compressor 100 goes through condenser 101, by connecting condenser 102 through this fourth connection 108 to a compressor suction line via a bypass line, condenser 102 can be evacuated, provided there are suitable check valves (not depicted) in place to prevent the evacuation of condenser

101. The same applies when all the flow goes through condenser 102. In this case condenser 101 is evacuated through the fourth outlet 108. If both condensers 101, 102 are active, the bypass line is disconnected.

In Figure 2, the embodiment of a flow control valve according to Figure 1 is illustrated schematically in sectional views of different states (a) through (g). The flow control valve is first described generally, before reference is made to the different states (a) through (g). The flow control valve comprises a housing 1 forming four internal passages 8 and an internal cavity 2 in fluid communication with each of the internal passages 8, each of the internal passages 8 comprising an orifice 15 opening into the inner cavity 2. A flow direction block 3 is arranged in the internal cavity 2, the flow direction block 3 having an outer face 4 encircled by an inner face 5 of the internal cavity. So, if the internal cavity 2 is cylindrical the respective flow direction block 3 is formed as a cylinder as well, tightly fitting into the internal cavity. The cylindrical form of the flow direction block 3 is best recognised in Figure 6. However, other geometries, as a sphere or cone may equally be used for the flow direction block 3.

The flow direction block 3 comprises two clearances 6, 7 extending through a portion of the flow direction block 3, wherein each of the two clearances 6, 7 is adapted to selectively connect at least two of the internal passages 8 of the housing 1 when the flow direction block 3 is rotated around a rotation axis X in the centre of the internal cavity 2, perpendicular in respect to the plane of projection. In Figure 2, the section through the valve housing 1 shows the internal passages 8, which are arranged in a common plane in the depicted embodiment, but do not have to. Hence, the section shows the two clearances 6, 7 as well, which means that of the flow direction block 3 only a segregating portion 40 is arranged in the plane of section. The two clearances 6, 7 are adapted to allow a flow through the at least one of the two clearances 6, 7 to be controlled independently of a flow through the other one of the two clearances 6, 7 by way of rotating the flow direction block 3. According to the invention, the two clearances 6, 7 and the orifices 15 are arranged such, that in at least one angular position of the flow direction block 3 one of the two clearances 6, 7 connects at least three of the internal passages 8, wherein a volume of the two clearances 6, 7 is asymmetrical with respect to any point along the rotation axis X. For example, a volume of the first clearance 6 is larger than a volume of the second clearance 7, and the first clearance 6 is adapted to connect at least three of the internal passages 8. Preferably, the segregating portion 40 of the flow direction block 3 disposed between the two clearances 6, 7 is offset from the rotation axis X towards the second clearance 7. The elements shown in the different states (a) through (g) of Figure 2, are identical. Thus, for the sake of clarity, the reference numerals are omitted in most states.

The concept of flow guidance and control of the flow control valve is now described with reference to the different states depicted in (a) through (g). A cross section of the internal cavity 2 forms two separated volumes within the housing 1. By off-setting the segregating portion 40 of the flow direction block 3 from the rotation axis X, a state (d) is introduced, in which top and bottom internal passages 8 are in direct connection with the internal passage 8 on the left. The divided flow is illustrated by the two arrows. Additionally, the top and bottom internal passage 8 may be off-set from a centreline through the axis X, towards the internal passage 8 on the left, additionally.

Rotating the flow direction block 3 slightly to either direction reduces the cross section of one of the flow cross sections of one of the internal passages 8, as the segregating portion 40 is moved over the respective orifice 15, while the other one of the internal passages 8 remains unrestricted, cf. states (c) and (e). This enables the intentional reduction of flow into the restricted internal passage 8, as the amount of flow depends on the cross section and therefore on the angle of the flow direction block 3. The restricted flow is illustrated by a broken arrow. Further rotation leads to closing and disconnecting one of the internal passages 8, cf. states (b) and (f). Continuing the rotation finally opens a second separated flow path, illustrated by another arrow through the second clearance 7, while the other one still remains unrestricted, cf. states (a) and (g). If required, an intermediate state between state (a) and state (b) analogous to state (c) can be introduced, which restricts the flow through the second clearance 7 and allows control of the flow. Further, if required, an intermediate state between state (f) and state (g) analogous to state (e) can be introduced, which restricts the flow through the second clearance 7 and allows control of the flow.

While control in the way described is advantageously possible, it is very sensitive to angular errors. This holds especially true for small flow rates. For example, for a re frigerant valve with typical dimensions an intended reduction from 10% to 5% cross section may result in approximately 0,5 mm relative movement of the sealing surfaces 4, 5, hence about 2 degree of rotation. Such an accuracy is achievable, but costly. Therefore, a preferred feature is introduced which essentially adds a transmission between angle of rotation of the flow direction block 3 and effective cross section of the internal passages 8, especially for lower flow rates. Two possible concepts are hereinafter described with reference to Figures 3 and 4.

In Figure 3, an embodiment of the flow control valve is depicted schematically in a sectional view in three different positions marked (a) to (c), wherein the outer face 4 of flow direction block 3 at the segregating portion 40 comprises a sealing sector 41 and at least on one end a bulge sector 42. The bulge sector 42 extends from the segregating portion 40 into the respective clearance 6, 7. A radius of the outer face 4 in the sealing sector 41 equals a radius of the inner face 5, as does the general radius of the flow direction block 3. Between the bulge sector 42 and the inner face 5, however, opens a slit, because a distance from the outer face 4 in the bulge sector 42 to the axis X is less than the radius of the inner face 5. The outer face 4 in the bulge sector 42 is preferably curved, as in the depicted embodiment. The radius of the curved outer face 4 in the bulge sector 42 decreases in circumferential direction from the sealing sector 41 towards the first clearance 6. The elements shown in the different states (a) through (c) of Figure 3, are identical. Thus, for the sake of clarity, the reference numerals are omitted in most states.

Due to the bulge sector 42 on the flow direction block 3, the flow direction block 3 needs to travel a significantly larger distance for the same reduction of flow and is hence less sensitive to angular changes. The bulge sector 42 is formed in such a way, that the effective opening cross section of the internal passage 8 decreases slowly and steadily with the rotation of the flow direction block 3 as soon as it is positioned over the orifice 15, cf. positions (a) with unrestricted flow, (b) with partly restricted flow and (c) with not yet fully restricted flow, compared to Figure 2 with states (d), (c) and (b). The two parallel lines illustrate the diminishing cross-section of the flow through the internal passage 8. The shape of the bulge sector 42 determines its transfer function and can be designed in such a way that especially in the sensitive region of small flow rates, the reduction of effective cross section requires a signifi cantly larger travel.

In Figure 4, an embodiment of the flow control valve is depicted schematically in three different positions marked (a) to (c), wherein at least one of the orifices 15 comprises a cutout 45 extending a flow cross-section of said at least one orifice 15 above a cross-section of the respective internal passage 8. Again, the elements shown in the different states (a) through (c) of Figure 4, are identical. Thus, for the sake of clarity, the reference numerals are omitted in most states. The cutout 45 preferably extends in circumferential direction of the inner face 5 of the internal cavity 2 and a width of the cutout 45 in axial direction is less than a diameter of the respective internal passage 8. The width of the cutout 45 in axial direction decreases starting from the internal passage 8 in circumferential direction towards an end of the cutout 45. Preferably, the cutout 45 is formed as a spout.

The cutout 45 increases the angle the flow control block 3 needs to travel in order to reduce the effective cross section by a given amount, when compared to Figure 2 with states (d), (c) and (b), for example. Preferably, the cutout 45 when introduced on the lower internal passage 8 as depicted in Figure 4, is formed in such a way that the smallest path decreases with clockwise rotation. The height of the cutout 45, meaning its extension into the plane of projection, should not be as large as the internal passage 8, but instead rather small to reduce the effective cross section also in that dimension. Even better is an increasing height towards the orifice 15. By closing the nominal orifice 15 of state (a), as illustrated in state (b), the complete flow will run through the cutout 45. The more of the cutout 45 is covered by the flow direction block 3, the lower the effective cross section and the lower the flow, cf. state (c). The two parallel lines illustrate the diminishing cross-section of the flow through the internal passage 8.

Of course, either of the control features as described in respect of Figures 3 and 4 can be introduced on either position of the flow direction block 3 and/or the internal cavity 2, allowing an improved control for any orifice 15. A combination of both features is of course equally possible.

Figures 5A and 5B show schematically two preferred embodiments of the flow control valve according to the invention in a sectional view. Both embodiments comprise a sealing arrangement 12 between the outer face 4 and the inner face 5. The illustration of Figure 5A shows a possible sealing arrangement 12 with a single sealing ring 43, which has the drawback, however, that the sealing properties may be insufficient for certain applications, as illustrated by the arrow L representing a leakage flow past the sealing ring 43. The sealing arrangement 12 illustrated in Figure 5B comprises two sealing rings 43 arranged in parallel, preventing the leakage flow past a single sealing ring 43. It is, however, not necessary to arrange the sealing rings 43 in parallel. The arrangement rather depends on the geometry of the flow direction block 3. Each of the two sealing rings 43 is arranged alongside one of two boundaries of the sealing sector 41 on the outer face 4 of the segregating portion 40 between the two clearances 6, 7. If there was a bulge sector 42 arranged adjacent to the sealing sector 41, as in the embodiment shown in Figure 3 above, the respective boundary would run inside the sealing sector 41, adjacent to the bulge sector 42. Further, the sealing arrangement 12, independent of how many sealing rings 43, encircles at least one of the two clearances 6, 7. The person skilled in the art will be able to find other sealing solutions, which may be equally feasible. A possible practical implementation is described with reference to Figure 6 below.

In Figure 6, a flow direction block 3 is depicted in different views, which will be described together. For the depicted flow direction block 3 to be according to the invention, the volume of the two clearances 6, 7 needs to be asymmetrical with respect to any point along the rotation axis X, which cannot be verified from the depicted views. The top view (a) shows the flow direction block 3 in perspective. A rotational body is depicted, of which the cylindrical part with the highest diameter is actually the functional part of the flow direction block 3. The middle illustration (b) and the bottom illustration (c) show different side views, which are offset 90 degree around the rotation axis X. The two clearances 6, 7 in the form of open channels of the flow direction block 3 are separated from each other by the segregating portion 40 in the form of a ridge.

The open channel forming one of the clearances 6 is encircled by the sealing ring 43, which is not depicted, but which is to be inserted into a seat 35 or groove 35. The groove 35 and hence the sealing ring 43, when inserted, form a closed loop on the outer face 4 of the flow direction block 3. It is possible that of the two open channels 6, 7, only one open channel 6 is encircled by the groove 35 for the sealing arrangement 12, as depicted. If each of the clearances 6, 7 is encircled by a sealing ring 43, respectively, two sealing rings 43 would be arranged adjacently in the sealing sector 41 of the outer face 4, which will be discussed further with respect to Figures 7A and 7B. The groove 35 is provided in the outer face 4 to accommodate the sealing ring 43. The groove 35 is preferably provided with undercuts to securely fasten the sealing ring 43 in the groove 35, between the outer face 4 and the inner face 5 of the internal cavity 2.

In Figures 7A and 7B, two possible implementations of the sealing arrangement 12 are schematically depicted. In the illustration of Figure 7B, the two sealing rings 43 are arranged such that the first sealing ring 43 encircles the first clearance 6 and that the second sealing ring 43 encircles the second clearance 7. However, in the sealing sector 41 of the outer face 4, each of the sealing rings 43 runs alongside one of the boundaries of the sealing sector 41, which are arranged in parallel in this illustration, but do not have to be.

In the illustration of Figure 7A, the two sealing rings 43 are arranged such that both sealing rings 43 encircle the second clearance 7. In the sealing sector 41 of the outer face 4, again, each of the sealing rings 43 runs alongside one of the boundaries of the sealing sector 41. According to the depicted variant, the sealing rings 43 are arranged in parallel, but again, do not have to be. As an alternative arrangement the sealing rings 43 may equally encircle clearance 6, of course.

In Figure 8, a detail of the internal cavity 2 with an internal passage 8 and the segregating portion 40 of the flow direction block 3 is schematically depicted to illustrate a challenge with the sealing arrangement 12 in three positions. The sealing ring 43, which is preferably an O-ring 43, though other sealing rings might be equally feasible, and is referred to as such in the following description synonymously, can jump out of its seat 35, whenever it moves over the orifice 15 of an internal passage 8, particularly when the internal passage 8 is under lower pressure than the pressure the O-ring 43 is subjected to from the opposite side. In position (a) the sealing ring 43 is held in position in the seat 35 as the sealing ring is restrained between the outer surface 4 of the flow direction block 3 and the inner surface 5 of the inner cavity 2. The force exerted on the sealing ring 43 by the pressure difference over the sealing ring 43 is illustrated by an arrow P. As soon as the O-ring 43 moves over the orifice 15 of the internal passage 8, in position (b), the exerted force P deforms the sealing ring 43 and begins to push the sealing ring 43 out of the seat 35 towards the internal passage 8. In position (c) the sealing ring 43 is fully pushed out of the seat 35 into the internal passage 8. To prevent this behaviour of the sealing arrangement 12, two preferred approaches are described as follows. A first approach is described with respect to Figure 8.

Preferably, the O-ring 43 is fixed in the critical positions (b) and (c). For example, the orifices 15 of the internal passages 8 are covered by a mesh or net (not depicted), which holds the O-rings 43 in the respective seat 35 when they are prone to jump out. An alternative example would be to provide a special shape for the seat 35 in which the O-ring 43 is seated. The undercut groove 35 for the sealing ring 43, which is depicted and described with respect to Figure 6, before, would be an example of such a shape for the seat 35. A second approach will be described in connection with Figure 9, below.

In Figure 9, the switching procedure between different valve functions is depicted schematically in states (a) to (h) of the flow control valve according to the invention. The elements shown in the different states (a) through (h) of Figure 9, are identical. Thus, for the sake of clarity, the reference numerals are omitted in most states. According to a preferred embodiment, the sealing rings 43 are secured in their respective seats 35 by reducing a pressure difference between opposite sides of the O-ring 43 prior to positioning the sealing ring 43 over the orifice 15 of one of the internal passages 8. This may advantageously be achieved by a small drill hole (not depicted), connecting the internal passage 8 with the internal cavity 2 in such a way that the orifice 15 of the internal passage 8 is bypassed. Preferably, each internal passage 8 comprises two such drill holes, one at each side, as the sealing ring 43 may approach the orifice 15 from each of both directions. By allowing a small flow through the respective drill hole, the pressure on both sides of the O-ring 43 is advantageously equalized before switching. Without the pressure difference, no force acts on the O-ring 43 and it remains in its seat 35.

According to a further preferred embodiment, instead of introducing drill holes, the equalization of the pressure difference is ensured by allowing a flow through the cutouts 45, as described as a control feature before, with respect to Figure 4. In fact, in the preferred embodiment comprising the cutouts 45, they are used for both the equalization of the pressure difference as well as for improved flow control. This will now be further explained in the description of the switching sequence through states (a) to (h).

In the preferred embodiment of the flow control valve according to Figure 9, cutouts 45 are used for improved flow control. The same cutouts 45 are also used to equalize the pressure on opposite sides of the sealing rings 43 prior to switching as described earlier. The use of a bulge sector 42 for flow control (Figure 3), as well as an additional fixation for the O-rings 43 may optionally combined with this embodiment. The switching procedure is illustrated by states (a) to (h) and runs as follows. In state (a) there are two separate flows illustrated by arrows F. With reference to the exemplary system in Figure 1, the first flow comes from the left hand internal passage 8. The pressure is high on the bottom left side in the first clearance 6 and it is low on the top right side in the second clearance 7. The second flow comes from the top internal passage 8. Both flows are separated by the two O-rings 43. The pressure in the small volume between the O-rings 43 and the housing 1 depends on the previous states. In state (b) the right O-ring 43 enters the orifice 15 of the top internal passage

8. Due to a small flow between the housing 1 and the top internal passage 8, indicated by an arrow R, the pressure is equalized, leading to a removal of the pressure difference between opposite sides of the right O-ring 43. Both flows remain unrestricted as all the orifices 15 are fully open. In state (c) the right O-ring 43 enters the orifice 15 of the internal passage 8, but remains in the seat 35, as there is no pressure difference between both sides of the O-ring 43 which would produce any force acting on the O-ring 43. Optionally, this state may be used to reduce the second flow from the top internal passage 8 to the right hand internal passage 8 in a controlled manner after the pressures are equalized, which is illustrated by a broken arrow.

In state (d) the right O-ring 43 is fixed again, the top internal passage 8 is disconnected and the first flow still remains unrestricted. In states (e), (f) and (g) the posi tion of the flow direction block 3 remains unchanged between states (e) and (f). The left O-ring 43 is positioned above the orifice 15 of the top internal passage 8, but still sufficiently fixed due to the small height of the cutout 45. When entering the state (e), there will be a small flow R through the cutout 45, which equalizes the pressure on opposite sides of the left O-ring 43. As soon as this is finished, in state (f), the flow rate can be controlled by exposing more or less of the cutout 45 by increasing or decreasing the angle of the flow direction block 3, or allowing even more flow by exposing more area behind the cutout 45, as shown in state (g). In state (h) the maximal cross section for the flow is opened for both components connected to the top and bottom internal passages 8 at the same time, allowing maximal flow. As the valve as depicted in Figure 9 is designed symmetrically with respect to an imagined centreline (not depicted) through the centres of the left hand and right hand internal passages 8, the same cycle will be repeated on the other side upon further rotation. This is not illustrated. Whether or not the valve comprises such a symmetry, depends on the respective application. When switching back again, it is unlikely for the O-rings 43 to leave their seat 35, as the high pressure is always on their left side, forcing the sealing ring 43 in position. This depends, however, on the application of the flow control valve. It is of course equally possible to introduce a drill hole or cutout 45 as described before on the right hand side of the orifice 15 to equalize the pressure difference, if it was required. It is noteworthy, that the pressure between the O-rings 43, as well as within the housing 1, changes repeatedly from high to low, while switching from state to state. In a sealing arrangement 12 as described with reference to Figure 7A, the volume of the housing 1 is in fluid contact with the volume enclosed by the two O-rings 43 and hence follows these pressure changes. This is of importance, as refrigerant flows cyclically in and out of the volume enclosed by the two O-rings 43. The amount of refrigerant is negligible for the function of the system, but the oil that moves with this refrigerant helps to ensure a sufficient lubrication of the O-rings 43.

Another preferred embodiment is described with respect to Figure 10. Again, Figure 10 depicts different states (a) to (d) of the flow control valve schematically. The preferred embodiment further comprises a large cutout 46 enlarging the orifice 15 of the left internal passage 8. This advantageously allows additional states, which may be required, for example, for diagnostics (a), repair (b), evacuation (c) or filling of refrigerant (d). For achieving those states other solutions may also be suitable.

Numerals

Housing, valve body

Internal cavity

Flow direction block

Outer face

Inner face

Clearance, first clearance

Clearance, second clearance

Internal passages

Sealing arrangement

Orifice

Seat, groove

Segregating portion

Sealing sector

Bulge sector

Sealing ring, O-ring

Cutout, spout

Large cutout

Compressor

Condenser

Expansion valve

Evaporator

First connection

Second connection

Third connection

Fourth connection

4-way valve

Rotation axis

Arrow, leakage

Arrow, pressure

Arrow, pressure equalisation

Arrow, flow

Claims

1. Flow control valve, comprising a housing (1) forming a number of internal passages (8) and an internal cavity (2) in fluid communication with each of the internal passages, each of the internal passages comprising an orifice (15) opening into the inner cavity;

a flow direction block (3) arranged in the internal cavity, the flow direction block having an outer face (4) encircled by an inner face (5) of the internal cavity, wherein the flow direction block comprises two clearances (6, 7) extending through a portion of the flow direction block, wherein each of the two clearances is adapted to selectively connect at least two of the internal passages of the housing when the flow direction block is rotated around a rotation axis (X) relative to the housing, wherein the two clearances are adapted to control a flow through at least one of the two clearances by way of rotating the flow direction block, wherein the two clearances (6, 7) with a segregating portion (40) of the flow direction block (3) arranged between the two clearances and the orifices (15) are arranged such, that in at least one angular position of the flow direction block (3) one of the two clearances (6, 7) connects at least three of the internal passages (8), wherein a volume of the two clearances (6, 7) is asymmetrical with respect to any point along the rotation axis (X).

2. Flow control valve according to claim 1, characterized in that the segregating portion (40) is offset from the rotation axis (X).

3. Flow control valve according to any one of claims 1 or 2, characterized by four internal passages (8) connected externally to a refrigerant circuit, wherein a first internal passage is connected to a compressor output, a second internal passage and a third internal passage are each connected to a separate condenser and wherein one of the clearances (6, 7) is adapted to connect, in at least one angular position of the flow direction block (3), both the second internal passage and the third internal passage to the compressor output.

4. Flow control valve according to any one of the preceding claims, characterized in that the outer face (4) of the segregating portion (40) comprises a sealing sector (41) and at least on one end a bulge sector (42), wherein a radius of the outer face in the sealing sector equals a radius of the inner face (5) and wherein a distance of the outer face to the rotation axis (X) in the bulge sector is less than the radius of the inner face.

5. Flow control valve according to claim 4, characterized in that the outer face (4) in the bulge sector (42) is curved.

6. Flow control valve according to claim 5, characterized in that a radius of the curved outer face in the bulge sector (42) decreases in circumferential direction from the sealing sector (41) towards a respective one of the two clearances (6, 7).

7. Flow control valve according to any one of the preceding claims, characterized in that at least one of the orifices (15) comprises a cutout (45) extending a flow cross-section of said at least one orifice with respect to a cross-section of the respective internal passage (8).

8. Flow control valve according to claim 7, characterized in that the cutout (45) extends in circumferential direction of the inner face (5) of the internal cavity (2).

9. Flow control valve according to any one of claims 7 or 8, characterized in that a width of the cutout (45) in axial direction is less than a diameter of the respective internal passage (8).

10. Flow control valve according to claim 9, characterized in that the width of the cutout (45) in axial direction decreases starting from the internal passage (8) in circumferential direction towards an end of the cutout.

11. Flow control valve according to any one of claims 7 through 10, characterized in that the cutout (45) is formed as a spout.

12. Flow control valve according to any one of the preceding claims, characterized in that the orifices (15) of the internal passages (8) are covered by a mesh or net.

13. Flow control valve according to any one of the preceding claims, characterized in that a sealing arrangement (12) is arranged between the outer face (4) and the inner face (5), the sealing arrangement comprising at least one sealing ring (43), wherein the sealing ring encircles either one of the two clearances (6, 7).

14. Flow control valve according to claim 13, characterized in that the sealing arrangement (12) comprising at least two sealing rings (43), wherein the two sealing rings either encircle the same one of the two clearances (6, 7), or wherein both of the two clearances (6, 7) are each encircled by at least one sealing ring, respectively.

15. Flow control valve according to claim 14, characterized in that each of the two sealing rings (43) is arranged alongside one of two boundaries of a sealing sector in the outer face (4) of the segregating portion (40) of the flow direction block (3), respectively.