Abstract:
A coupling is provided preferably for a vortex valve for use on an outlet pipe in a sewerage system. The coupling comprises an outer component for insertion into a bore of a pipe, and an inner component which is inserted into the outer component, ramp means being provided between the two components, whereby the outer component is expanded to seal against the bore when the inner component is inserted into the outer component so as to engage the second ramp portion. The ramp means comprise first and second portions of different inclinations. The vortex valve has a circumferential inlet which is adjustable.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application is a divisional of application Ser. No. 10/505,946, now pending, which is the National Stage of International Application No. PCT/GB03/00565, filed Feb. 7, 2003 (which is hereby incorporated by reference). 
     
    
     BACKGROUND OF THE INVENTION AND PRIOR ART  
       [0002]     This invention relates to a vortex valve having a variable inlet.  
         [0003]     A vortex valve is disclosed in WO-A-99/43899. Such valves are used, for example in sewerage systems, for controlling fluid flow by a hydraulic effect without requiring moving parts. Such devices have a vortex chamber provided with an outlet at one axial end and an inlet arranged to cause swirl in the chamber when a certain critical flow has been attained. WO-A-99/43899 discloses a vortex valve in which the vortex chamber is defined by a circular cylindrical wall and two axial end walls.  
         [0004]     At low flow rates, water entering through the inlet of a vortex valve passes through the vortex chamber to the outlet with substantially no pressure drop, and the valve can be considered to be open. At high flow rates, water enters through the inlet with enough energy to create a vortex in the vortex chamber which results in a significant pressure drop between the inlet and the outlet, which may greatly restrict flow through the outlet, or even substantially cut it off altogether. Thus the valve serves to limit the rate of flow automatically. Vortex valves can be used, for example, to control the flow of stormwater in sewers, to ensure that equipment downstream of the valve is not overloaded during periods of heavy rainfall.  
         [0005]     Vortex valves are commonly installed in a collection chamber in which rain water, drained from road surfaces and other paved areas, collects. An outlet pipe extends from a wall of the collection chamber to a sewer, and the vortex valve is mounted so that its outlet makes a water-tight connection with the end of the outlet pipe. WO-A-99/43899 discloses mounting means for this purpose which comprises a first element fitted to the end wall of the vortex valve about its outlet opening, and a second element which is fitted to the outlet pipe. The vortex valve can then be fitted to the outlet pipe by connecting the two elements together.  
         [0006]     The mounting means disclosed in WO-A-99/43899 requires the fitting of the second element to the outlet pipe. This is not always easy to achieve in a manner which will provide a water-tight connection between the vortex valve and the outlet pipe and is, in any case, a time consuming operation requiring fasteners and power tools.  
       SUMMARY OF THE INVENTION  
       [0007]     According to one aspect of the present invention, there is provided a coupling for engagement with a bore, the coupling comprising an outer component having an expandable ring having a central axis, and an inner component which is longitudinally displaceable within the ring, ramp means being provided between the inner component and the ring whereby longitudinal displacement of the inner component within the ring causes radial expansion of the ring to engage the bore, the ramp means comprising a ramp surface on one of the components and a circumferential projection on the other component, the ramp surface having first and second portions of differing inclination to the central axis, whereby the circumferential projection engages the ramp surface portions successively as the inner component is displaced longitudinally relative in the ring.  
         [0008]     In a preferred embodiment, a coupling in accordance with the present invention is used to mount a vortex valve on an outlet pipe which defines the bore. The inner component is preferably fixed to an end wall of the vortex valve, and may be integral with the housing of the vortex valve. Thus, the inner component may comprise a spigot projecting axially from the vortex valve and surrounding the outlet of the vortex valve.  
         [0009]     The ramp surface is preferably provided on the inner component, and the circumferential projection is provided on the ring of the outer component, for engagement with the ramp surface.  
         [0010]     In a preferred embodiment, the first portion of the ramp surface is inclined by a smaller angle than the second portion to the direction of longitudinal displacement, and is situated ahead of the second portion with respect to the direction of longitudinal displacement of the inner component corresponding to expansion of the ring.  
         [0011]     The coupling may include rotational ramp means between the inner and outer components whereby rotation of the inner component relatively to the outer component longitudinally displaces the two components in relation to each other. Preferably, the rotational ramp means remains disengaged as the first portion of the ramp surface is operative, whereby the circumferential projection engages the first portion of the ramp surface during longitudinal displacement of the components relatively to each other, without requiring rotation. When the circumferential projection contacts the second portion of the ramp surface, the rotational ramp means is engaged, and subsequently rotation of the components relatively to each other longitudinally displaces the two components in relation to each other, causing the circumferential projection to move over the second portion of the ramp surface.  
         [0012]     The rotational ramp means may comprise at least one peg on one of the components which engages a helical groove in the other component.  
         [0013]     A seal may be provided on the outer surface of the ring to provide sealing between the coupling and the bore.  
         [0014]     The ring may be provided with at least one longitudinal slot, preferably extending from a free axial end of the ring, to provide for radial expansion of the ring. A plurality of the slots may be provided to divide the ring circumferentially into a plurality of resilient fingers. The circumferential projection may then be made up of a plurality of segments at the free ends of the fingers.  
         [0015]     In a preferred embodiment, the first portion of the ramp surface may be inclined to the longitudinal direction by an angle of 2° to 10°, for example 5°, and the second portion of the ramp surface may be inclined to the longitudinal direction by an angle of 30° to 50°, for example 40°.  
         [0016]     According to a second aspect of the present invention, there is provided a method of installing a vortex valve on a pipe by means of a coupling as defined above, the method comprising the steps of:  
         [0017]     fitting the ring of the outer component within the bore of the pipe,  
         [0018]     longitudinally displacing the inner component into the ring, such that the first portion of the ramp means provides a first expansion of the ring and subsequently the second portion of the ramp means provides a second expansion of the ring into sealing engagement with the bore.  
         [0019]     Preferably, in a method of installing a vortex valve provided with rotational ramp means, the inner component is displaced longitudinally into the outer component to engage the rotational ramp means, and subsequently rotation of the vortex valve causes operation of the rotational ramp means to displace the inner component longitudinally to cause the second expansion of the ring.  
         [0020]     According to a third aspect of the present invention, there is provided a vortex valve comprising a vortex chamber having a circular cylindrical outer wall and a tangential inlet passage, the inlet passage opening into the vortex chamber at a circumferential aperture which is adjustable by means of a sliding plate which is movable across the circumferential inlet. The sliding plate may be arcuate so that it lies over the outer wall of the vortex valve and is slidable about the axis of the outer wall. Means may be provided for retaining the sliding plate in an adjusted position.  
         [0021]     Preferably, the inlet passage of the vortex valve is defined by a tangential extension of the cylindrical outer wall of the vortex valve, and by extensions of the axial end walls of the vortex valve, whereby the inlet passage is of rectangular form. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0022]     For a better understanding of the present invention and to show more clearly how it may be carried into effect, reference will now be made, by way of example, to the accompanying drawings, in which:  
         [0023]      FIG. 1  is an end view of a vortex valve;  
         [0024]      FIG. 2  is a side view taken in the direction of the arrow II in  FIG. 1 ;  
         [0025]      FIG. 3  is an end view of a coupling member for use with the vortex valve of  FIGS. 1 and 2 ;  
         [0026]      FIG. 4  is a side view taken in the direction of the arrow IV in  FIG. 3 ;  
         [0027]      FIG. 5  shows a first stage in the fitting of the vortex valve of  FIGS. 1 and 2  to a pipe by means of the coupling member of  FIGS. 3 and 4 ;  
         [0028]      FIG. 6  shows a second stage during the fitting of the vortex valve;  
         [0029]      FIG. 7  shows a final stage in the fitting of the vortex valve; and  
         [0030]      FIG. 8  is an enlarged view corresponding to  FIG. 1  showing adjustment of an inlet of the vortex valve. 
     
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS  
       [0031]     The vortex valve shown in  FIGS. 1 and 2  comprises a vortex chamber  2  defined by a circumferential outer wall  4  and axial end walls  6 ,  8 . The vortex valve has an inlet passage  10  and an outlet  12 . The inlet passage  10  is rectangular, as seen in  FIG. 2 , and is defined by a tangential extension  14  of the outer wall  4 , and by lateral extensions  16 ,  18  of the axial end walls  6 ,  8 . The inlet passage  10  communicates with the vortex chamber  2  via a circumferential inlet  11 . In the orientation shown in  FIG. 1 , the edges of the lateral extensions  16 ,  18  extend vertically, and they are tangential to the outer wall  4 . The outer wall  4  itself extends beyond its junction with the lateral extensions  16 ,  18 , as shown by the part  4 ′.  
         [0032]     An adjustment plate  20 , which is rectangular as shown in  FIG. 2  but arcuate as shown in  FIG. 1 , lies over the outer wall  4  and is slidable between the lateral extensions  16 ,  18  over an arcuate path (see  FIG. 8 ) to reduce the area of the circumferential inlet  11 . The plate  20  has a slot  22  which allows the plate to slide relatively to a fixing bolt  24  which can be tightened to retain the plate  20  in an adjusted position.  
         [0033]     The outlet  12  is disposed centrally in the axial end wall  8 . A spigot  26  is fixed to the end wall  8  and projects axially from it. The spigot  26  has an outer surface which, extending from its free end, has three portions, namely a first ramp surface  28 , a second ramp surface  30  and a cylindrical surface  32 . A pair of diametrically oppositely disposed pegs  34  project from the cylindrical surface  32  close to the end wall  8 .  
         [0034]     The first ramp surface  28  is inclined to the axis of the spigot  26  by a smaller angle than the second ramp surface  30 . In the embodiment shown in the drawings, the angle of inclination of the first ramp surface  28  is 5°, and that of the second ramp surface 40°.  
         [0035]     The vortex valve of  FIGS. 1 and 2  may be made of any suitable material, for example steel or plastics material. In the preferred embodiment, it is made from a plastics material, and the spigot  26  is formed integrally with, or welded or otherwise bonded to, the end wall  8 .  
         [0036]     Alternatively, the spigot  26  may be removably attached to the wall  8  to allow for replacement of the spigot  26  or to allow use of the vortex valve with spigots of different diameter, in order to change the characteristics of the vortex valve.  
         [0037]     The coupling shown in  FIGS. 3 and 4  may also be made from plastics material and formed as an integral component. It comprises a flange  36  from which projects an expandable ring  38 . The flange  36  is non-circular, and includes a straight edge  40  (shown as the upper edge in  FIG. 3 ), which is connected to an arcuate edge portion  42  by two lateral straight edges  44 .  
         [0038]     As best seen in  FIG. 5 , a circumferential series of axially extending slots  46  extend from the end of the ring  38  away from the flange  36 , stopping short of the flange  36 . These slots  46  divide the free end region of the ring  38  into separate resilient fingers  48 . At the free end of the ring  38  there is an inwardly extending circumferential projection  50  which is divided by the slots  46  into separate segments  52  at the ends of the respective fingers  48 .  
         [0039]     The flange  36  has a central aperture  54  which coincides with the inner surface of the ring  38 . The internal surface of the flange  36  around the aperture  54  is provided with a pair of helical grooves  56  which are offset from each other by 180° around the axis of the flange  36 .  
         [0040]     As shown in  FIG. 5 , sealing rings  58  and  60  are fitted over the ring  38 .  
         [0041]      FIG. 5  shows an outlet pipe  62  which terminates at an end  64  in a stormwater collecting chamber. The vortex valve of  FIGS. 1 and 2  is fitted to the outlet pipe  62  as will now be described with reference to  FIGS. 5 and 7 .  
         [0042]     Initially, the ring  38  of the coupling member of  FIGS. 3 and 4  is inserted into the outlet pipe  62  until the flange  36  abuts the end  64  of the pipe  62 . Subsequently, the spigot  26  of the vortex valve is inserted into the coupling member. When the first ramp surface  28  engages the projection  50  made up of the segments  52 , the inclination of the ramp surface will cause the fingers  48  to be pushed radially outwardly as insertion of the spigot  26  continues. Since the slope of the first ramp portion  28  is of a relatively small angle of inclination, it is relatively easy to push the vortex valve manually towards the pipe  62  against the resistance provided by the resilient action of the fingers  48 . However, when the second ramp surface  30  reaches the projection segments  52 , shortly after the position shown in  FIG. 6 , the resistance to further longitudinal movement increases owing to the increased angle of inclination of the second ramp surface  30 . At this position, provided the rotational position of the vortex valve with respect to the coupling member is correct, the pegs  34  will be aligned with the helical grooves  56  where they emerge at the right-hand end face of the flange  36  (as viewed in FIGS.  5  to  7 ). The pegs  34  can thus enter the helical grooves  56 , whereupon rotation of the vortex valve relative to the coupling member will cause a rotational camming effect which draws the spigot  26  further into the ring  38 , causing the projection segments  52  to ride over the second ramp surface  30 , forcing the ends of the fingers  48  further apart to compress the seal  58  firmly against the inner bore of the pipe  62  (as shown in  FIG. 7 ).  
         [0043]     It will be appreciated that the engagement between the pegs  34  and the helical grooves  56  lock the vortex valve securely to the coupling member. Thus, the vortex valve is firmly secured to the outlet pipe  62  in a sealing-tight manner without requiring any special tools or fasteners. Furthermore, no specialised preparation of the pipe end  62  is required, and there is no need for the pipe  62  to project freely into the stormwater collecting chamber. For additional sealing purposes, a sealing ring  66  is provided to prevent leakage between the end wall  8  of the vortex valve and the flange  36  of the coupling member.  
         [0044]     The non-circular shape of the flange  36  assists in the proper positioning of the coupling member so that the pegs  34  can be engaged with the helical grooves  56 . Also, proper positioning of the coupling member when inserted into the pipe  62  (for example with the flat edge  40  uppermost and horizontal) will ensure that, in the final position of the vortex valve, the vortex valve itself is properly positioned in the collecting chamber, with the inlet passage  10  at the bottom.  
         [0045]     As shown in  FIG. 8 , the plate  20  can be displaced arcuately over the outer wall  4 , as shown in dashed outline, in order to reduce the area of the circumferential inlet  11 . A reduction in this area alters the characteristics of the vortex valve, and in particular alters the pressure head at the inlet at which a vortex will be initiated within the vortex chamber  2  to cause a braking action, and also varies the relationship between the pressure head and flow rate through the vortex valve once the vortex is established. Adjustment of the area of the circumferential inlet  11  may be made in conjunction with selection of a spigot  26  of appropriate diameter to provide the desired flow characteristics.  
         [0046]     It has been found that adjustment of the inlet area in this manner, in conjunction with a vortex chamber having a circular cylindrical outer wall surprisingly enhances the versatility of the vortex valve. This is because, by appropriate adjustment of the inlet area, the characteristics of the vortex valve can be varied to suit a significant range of required flow characteristics. This in turn means that the same size of vortex valve can be used in different circumstances, with only the inlet area being adjusted by means of the plate  20  (possibly in conjunction with selection of an appropriate spigot diameter) in order to suit the vortex valve to the particular circumstances of its installation. This leads to manufacturing efficiencies, since vortex valves no longer need to be designed specifically for each installation. Instead, a relatively small range of vortex valves of different dimensions is required, with each vortex valve being fine-tuned by way of the adjustment plate  20  to suit individual circumstances. For example, it is believed that a range of only four vortex valves of different dimensions is required to fulfill most needs of the market.  
         [0047]     An important aspect of the adjustment means of  FIG. 8  is that the adjustment plate  20  extends generally along an arc which is substantially coincident with the circle on which lies the cylindrical outer wall  4 . The plate  20 , when moved across the inlet to reduce the inlet area, thus contributes to the swirling movement within the chamber  2  when a vortex is established.