Device for Limiting or Keeping Constant a Flowing Quantity of Fluid

Abstract

Flow-limiting element (100) for limiting the flow of a fluid flowing therethrough, comprising a housing (1) provided with an inlet (2), an outlet (3); and a resilient plate-like valve element (4) which is arranged in the housing (1) and which is movable to and from a valve seat (9), defining a throughflow opening (11) therebetween, under the influence of a pressure of the fluid flowing therethrough and is arranged to adjust the size of the throughflow opening (11); wherein the valve seat (9) is arranged with a protruding member (113), having a footprint and a height, for limiting the movement of the resilient plate-like valve element (4) towards the valve seat (9), wherein the protruding member (113) comprises an engagement surface for engaging the resilient plate-like valve element (4), wherein the engagement surface is at least partially curved, wherein a radius of curvature of the at least partially curved engagement surface is equal to, or larger than, a smallest dimension of the footprint of the protruding member (113).

Claims

1. A flow-limiting element for limiting the flow of a fluid therethrough, comprising: a housing provided with an inlet, an outlet; and a resilient plate-like valve element which is arranged in the housing and which is movable to and from a valve seat, defining a throughflow opening therebetween, under the influence of a pressure of the fluid flowing therethrough and is arranged to adjust the size of the throughflow opening; wherein the valve seat is arranged with a protruding member, having a footprint and a height, for limiting the movement of the resilient plate-like valve element towards the valve seat and wherein the protruding member comprises an engagement surface for engaging the resilient plate-like valve element, wherein the engagement surface is at least partially curved, wherein a radius of curvature of the at least partially curved engagement surface is equal to, or larger than, a smallest dimension of the footprint of the protruding member.

2. The flow-limiting element according to claim 1, wherein the protruding member has a substantially rectangular footprint having a respective width and length, wherein the radius of curvature of the at least partially curved engagement surface is equal to, or larger than, at least one of the respective width and length.

3. The flow-limiting element according to claim 1, the footprint of the protruding member is defined by a circle with a certain width that is equal to the diameter of the footprint, wherein the radius of curvature of the at least partially curved engagement surface is equal to, or larger than the width.

4. The flow-limiting element according to claim 1, wherein the at least partially curved engagement surface is arranged to elastically flatten under influence of an applied pressure.

5. The flow-limiting element according to claim 1, wherein the engagement surface comprises beveled and/or rounded edges and/or wherein a full engagement surface is a curved surface.

6. The flow-limiting element according to claim 1, wherein the engagement surface of the protruding member is a double curved and/or spherical engagement surface.

7. The flow-limiting element according to claim 1, wherein the radius of curvature of the at least partially curved engagement surface is at least 1.2 times the smallest dimension of the footprint of the protruding member.

8. The flow-limiting element according to claim 1, wherein the radius of curvature of the at least partially curved engagement surface is at least 5 times the height of the protruding member.

9. The flow-limiting element according to claim 1, wherein the valve element is retained on one side and the valve element can move resiliently on the opposite side in the direction of the valve seat, wherein the flow-limiting element comprises a plurality of protruding members, and wherein the protruding members are arranged at different heights with respect to the valve seat.

10. The flow-limiting element according to claim 9, wherein the plurality of protruding members comprises a first set of two protruding members, and wherein the two protruding members of the first set are arranged on opposing sides with respect to the throughflow opening in the housing.

11. The flow-limiting element according to claim 10, comprising a second set of protruding members, wherein the two protruding members of the second set are arranged on one of the resilient plate-like valve element and the housing at distances further from the retained side of the valve element when compared to the protruding members of the first set.

12. The flow-limiting element according to claim 7, wherein the radius of curvature of the at least partially curved engagement surface is at least 1.5 times the smallest dimension of the footprint of the protruding member.

13. The flow-limiting element according to claim 7, wherein the radius of curvature of the at least partially curved engagement surface is at least 2 times the smallest dimension of the footprint of the protruding member.

14. The flow-limiting element according to claim 8, wherein the radius of curvature of the at least partially curved engagement surface is at least 10 times the height of the protruding member.

15. The flow-limiting element according to claim 8, wherein the radius of curvature of the at least partially curved engagement surface is at least 15 times the height of the protruding member.

Description

[0027] The present invention is further illustrated by the following Figures, which show preferred embodiments of the flow limiting element, and are not intended to limit the scope of the invention in any way, wherein:

[0028] FIG. 1 shows a cross-sectional view of a flow limiting element according to a first embodiment.

[0029] FIG. 2 shows an upper view of the flow limiting element according to the first embodiment.

[0030] FIG. 3 shows in a cross-sectional view the details of a protruding member of the flow limiting element according to the first embodiment.

[0031] FIG. 4 shows a cross-sectional view of a flow limiting element according to a second embodiment.

[0032] FIG. 5 shows an upper view of the flow limiting element according to the second embodiment.

[0033] FIG. 6 shows in a cross-sectional view the details of a protruding member of the flow limiting element according to the second embodiment.

[0034] FIG. 1 shows a cross-sectional view of a flow limiting element 100 according to a first embodiment. Flow limiter 100 comprises a housing 1, which has as an inlet 2 a fluid opening on the upstream side and as an outlet 3 a fluid opening on the downstream side. The direction of flow is indicated by the different arrows A and is in the direction of the inlet 2 to the outlet 3. Within the housing 1 a resilient plate-like valve element 4 is arranged, comprising a retained section 7 and a resiliently movable section 8. The plate-like resilient valve element 4 is supported on a support part 5 in the central downstream part of housing 1, wherein said support part 5 and a cushion part 6 in the peripheral upstream part of housing 1 hold in place the retained section 7 of resilient plate-like valve element 4. This fixation is brought about as follows. The resilient valve element 4 in principle lies unattached in housing 1 and is supported on one side over the whole width by support part 5 and held in place by a pin 16 on support part 5 which fits loosely in a hole arranged in resilient element 4. Both sides, i.e. the smaller retained section 7 and the larger resilient section 8 of the resilient element are exposed to the water pressure and a force is therefore exerted on both sides. The outer end of retained section 7 on the opposite side of resilient valve element 4 rests against cushion 6, whereby the resilient valve element 4 is fixed in its position by the flow of the liquid. The size of the throughflow opening 11 can be adjusted in the rest state of valve element 4 by adjusting the thickness of cushion 6. The resilient section 8 of plate-like valve element 4 determines, together with a valve seat 9 with thickness 10 inclining downward to the outer end of resilient part 8, the width and length of the throughflow opening 11, wherein said opening 11, together with the space 12 lying on the liquid outlet side of resilient element 4, realizes a pressure drop such that the liquid flow rate at the outlet 3 is constant. In housing 1 protruding member 113 is also arranged on valve seat 9 such that under the influence of the inlet pressure they limit the stroke of resilient element 4.

[0035] FIG. 2 shows an upper view of the flow limiting element 100 according to the first embodiment. A pair of protruding members 113, 114, forming a first set, is arranged on valve seat 9 at respective distances d113, d114 as seen from the retained section of the valve element such that, under the influence of the inlet pressure, they jointly limit the stroke of resilient element 4 in the downward direction B (see again FIG. 1). The distances d113, d114 can be substantially equal, but can also be allowed to slightly differ from one and another. Each pair of protruding members 113, 114 can be arranged asymmetrically, i.e. the heights H113, H114 of the two members 113, 114 from the valve seat 9 differ to some extent. This creates bias in the resilient valve element 4, whereby vibrations of valve element 4 are reduced or even prevented. Also arranged in valve seat 9 are recesses 15 which influence the liquid flow in the flow limiting element 100 such that the direction of the outgoing liquid flow is substantially the same as the direction of the ingoing liquid flow.

[0036] Protruding members 113, 114 have respective widths W113, W114, lengths L113, W114 and heights H113, H114, thereby protruding member 113 has a substantially rectangular footprint. In addition, as is clearly seen in FIG. 3, the engagement surface 1131 of protruding member 113 is at least partially curved with a predefined radius of curvature R113. Protruding member 113 thereby takes the form of a sort of speedbump with substantially rectangular sides 1132 arranged at the ends of the curved engagement surface 1131. The engagement surface 1131 has a single curvature, whereby a central axis (not shown) of the curvature is substantially parallel to a virtual line 17 separating the retained section 7 and resiliently movable section 8 of the plate-like resilient valve element 4. The engaging surface 1131 of protruding member 113 is arranged to engage with the resilient plate-like valve element 4 if the pressure that is applied to the upstream side of the resilient plate-like valve element 4 is higher than a certain predefined threshold. As from that point onwards pressure starts to be applied directly to the protruding member 113 through its engaging surface 1131, the at least partially curved engagement surface, wherein the radius of curvature R113 of the at least partially curved engagement surface 1131 is equal to, or larger than, at least one of the respective dimensions, such as widths W113 and lengths L113. Alternatively, the radius of curvature R113 is based on the height H113 of the protruding member, wherein the radius of curvature R113 of the at least partially curved engagement surface is at least 5 times, preferably at least 10 times, more preferably at least 15 times the height of the protruding member.

[0037] FIG. 4 shows a cross-sectional view of a flow limiting element 200 according to a second embodiment. Flow limiting element 200 according to the second embodiment can be almost identical to the flow limiting element 100 according to the first embodiment. The difference is in the shape of the protruding member 213 when compared to protruding member 113. Again, the engagement surface 2131 is a curved surface, however, the curvature is extended over the full width W213 of protruding member 213 such that a smoother transition between the valve seat 9 and the protruding member 213 is obtained. The curved engagement surface 2131 is furthermore formed as a double curved, in this example a spherical engagement surface 2131. Also, the footprint of protruding member 213 is defined by a circle with a certain width W213, which is equal to the diameter of the footprint of protruding member 213. Protruding members 213, 214 can be arranged at respective distances d213, d214 as seen from the retained section of the valve element. These distances d213, d214 can be substantially equal, but can also be allowed to slightly differ from one and another. Also in this embodiment each pair of protruding members 213, 214 can be arranged asymmetrically, i.e. the heights H213, H214 of the two members 213, 214 from the top of the valve seat 9 differ to some extent.

[0038] The engaging surface 2131 of protruding member 213 is also arranged to engage with the resilient plate-like valve element 4 if the pressure that is applied to the upstream side of the resilient plate-like valve element 4 is higher than a certain predefined threshold. As from that point onwards pressure starts to be applied directly to the protruding member 213 through its engaging surface 2131, the at least partially curved engagement surface, wherein the radius of curvature R213 of the at least partially curved engagement surface 2131 is equal to, or larger than widths W214. Alternatively, the radius of curvature R213 is based on the height H213 of the protruding member, like is the case for the protruding member 113 of the first embodiment.

[0039] The valve seat 9 can, in all embodiments, further be provided with a secondary protruding member 223, or a pair of secondary protruding members 223, 224. The secondary protruding members are arranged such that protruding members 213, 214 and secondary protruding members 223, 224 are arranged on the valve seat 9, on opposite sides of the recess 15. Secondary protruding members 223, 224 are thus arranged at a distance further from the retained section 6 of the resilient plate-like member 4 and will tend to engage with the resiliently movable section 8 at higher pressures, at a point wherein the resiliently movable section 8 has already contacted the protruding members 213, 214. Thereby, the forces and/or stresses resulting from the pressure applied by the flow on the upstream side of the resilient plate-like valve 4, can be redistributed over the secondary protruding members 223, 224 thereby partly relieving the protruding members 213, 214. Longer operational lifetime is thereby achieved. Note that the pair of secondary protruding members 223, 224 can also be arranged asymmetrically, to even further avoid vibrations.

[0040] Although the embodiments described in the figures feature protruding members 113, 114, 213, 214 having respective rectangular and circular footprints, it is noted that the footprint of the protruding members may feature any shape defining a surface area, such as polygons with any number of sides, such as a triangle, quadrilateral, pentagon, hexagon, and so on; any shape (at least partially) composed of circular arcs, such as a circle, semicircle, circular sector, ellipse, and so on, or any combination of these shapes.

[0041] The present invention is not limited to the embodiment shown, but extends also to other embodiments falling within the scope of the appended claims.