Abstract
A liquid-ingress control device, comprising a casing having an interior and an exterior, and optionally, a liquid-activated trigger positioned in the casing interior, the casing comprising an exterior liquid entry control surface defined by a perimeter in sealing relationship with an edge of a cap, the cap having an interior cap surface formed to define a cap space between the interior cap surface and the liquid entry control surface; the liquid entry control surface comprising a liquid entry port comprising a tube extending between the exterior and interior of the casing through an aperture formed in the entry control surface, the tube optionally comprising a flange positioned exterior to the casing; the cap comprising at least two flow apertures positioned such that liquid contained within the cap space is capable of egress under gravity from the cap space, independently of the orientation of the device.
Claims
1. A liquid-ingress control device, comprising a casing having an interior and an exterior; the casing comprising an exterior liquid entry control surface defined by a perimeter in sealing relationship with an edge of a cap, the cap having an interior cap surface formed to define a cap space between the interior cap surface and the liquid entry control surface; the liquid entry control surface comprising a liquid entry port comprising a tube extending between the exterior and interior of the casing through an aperture formed in the entry control surface; the cap comprising at least two flow apertures positioned such that liquid contained within the cap space is capable of egress under gravity from the cap space, independently of the orientation of the device.
2. A device according to claim 1 wherein at least a portion of the liquid entry control surface is substantially planar.
3. A device according to claim 1 wherein the tube extends from the exterior of the casing at substantially 90 to the surface surrounding the tube.
4. A device according to claim 1 wherein the tube comprises a flange positioned exterior to the casing, wherein a surface of the flange proximal to the liquid entry control surface does not abut the liquid entry control surface.
5. A device according to claim 1 wherein the cap comprises at least 3, 4, 5 or at least 6 flow apertures.
6. A device according to claim 1 wherein at least one, or more, or all, of the flow apertures is each formed as a funnel through the material forming the cap, each funnel having an interior mouth and an exterior mouth, the exterior mouth being smaller than the interior mouth.
7. A device according to claim 1 wherein the cap comprises at least one ridge, each ridge being formed on the interior cap surface and extending between the periphery of a first flow aperture and the periphery of a second flow aperture.
8. A device according to claim 1, wherein the interior cap surface is at least partially formed as a concave curve.
9. A device according to claim 1, further comprising a liquid-activated trigger, wherein the liquid-activated trigger is positioned in the casing interior or is operably connected to the casing interior.
10. A device according to claim 1 comprising a liquid-activated trigger positioned in the casing interior, wherein the casing is formed by a first casing portion and a second casing portion, maintained in sealing relationship with one another by the liquid-activated trigger in an inactivated condition, the trigger comprising a liquid-releasable fixing and the trigger being moveable to an activated condition by contact of the liquid-releasable fixing with a liquid.
11. A device according to claim 10 wherein, when the trigger is in an inactivated condition, the liquid-releasable fixing binds a first attachment means forming part of the first casing portion to a second attachment means forming part of the second casing portion.
12. A device according to claim 10 wherein a tensioned resilient member is positioned between the first and second casing portions, the tensioned resilient member arranged to force the first casing portion out of sealing relationship with the second casing portion when the trigger is in an activated condition.
13. A device according to claim 1 wherein the casing is substantially elongate and the liquid entry control surface and cap are positioned at a first end of the casing.
14. A device according to claim 13 wherein the edge of the cap comprises a linear edge portion positioned distally from the first end of the casing, and a curved edge portion positioned proximally to the first end of the casing, the curved edge portion having a first end linked to a first end of the linear edge portion by a first side edge and a second end linked to a second end of the linear edge portion by a second side edge.
15. A device according to claim 14 wherein the cap comprises a first and a second flow aperture, both positioned at or close to the linear edge portion of the cap.
16. A device according to claim 14 comprising a third flow aperture positioned at or close to the first end of the casing and a fourth flow aperture positioned at or close to the first side edge and a fifth flow aperture positioned at or close to the second side edge.
17. A device according to claim 16, wherein the cap comprises at least one ridge, each ridge being formed on the interior cap surface and extending between the periphery of a first flow aperture and the periphery of a second flow aperture, comprising a first ridge extending between the periphery of the first flow aperture and the periphery of the third flow aperture, further comprising a second ridge extending between the periphery of the second flow aperture and the periphery of the third flow aperture.
18. A liquid-activated trigger control device, comprising a device according to claim 1 and a liquid-activated trigger positioned in the casing interior.
19. A man overboard rescue assistance device comprising a liquid-ingress control device according to claim 1.
20. A buoyancy aid comprising a liquid-ingress control device according to claim 1.
Description
BRIEF DESCRIPTION OF DRAWINGS
(1) Embodiments of the invention will now be described with reference to FIGS. 1-8 below, in which:
(2) FIG. 1 shows a device according to the invention in assembled form;
(3) FIG. 2 shows an end region of the device of FIG. 1 in disassembled form;
(4) FIG. 3 shows an exploded view of an end region of the device of FIG. 1;
(5) FIG. 4 shows a plan view (FIG. 4A) and a perspective view (FIG. 4B) of a cap for inclusion in the device of FIG. 1;
(6) FIG. 5 shows an interior view of the cap;
(7) FIG. 6 shows a cross-sectional view of a section of the device of FIG. 1 prior to ingress of water;
(8) FIG. 7 shows a lifejacket comprising a device as described in WO2016/020649, comprising the device of FIG. 1; and
(9) FIG. 8 shows a schematic arrangement of devices as shown in FIG. 1, when used in a flood alert system.
DETAILED DESCRIPTION
(10) FIG. 1 shows a device 1 according to the invention comprising a casing 5 formed from two halves 10a and 10b. The casing is approximately 140 mm in length, approximately 40 mm in width and approximately 32 mm in depth The casing has two ends 15a and 15b each having two caps 20a, 20b, 20c, 20d. Caps 20a and 20b are located at end 15a and caps 20c and 20d are located at end 15b. Caps 20a and 20c are engaged with casing half 10a and caps 20b and 20d are engaged with casing half 10b. Each cap is approximately 32 mm wide. Recesses for fixings 25, such as screws, involved in assembling the casing halves 10a and 10b to form casing 5 are also visible.
(11) FIG. 2 shows casing half 10a at end 15b with cap 20c removed. The exterior surface of the casing end region indicated as 30 (known as the cap region when the cap is in position), has three main sections, a vertical section 35a, an inclined section 35b and a horizontal section 35c. A liquid entry port is formed as an aperture in the material of section 35b and is shown as 40, through which water may enter the interior of the casing 5. The internal diameter of the port is approximately 3 mm.
(12) FIG. 3 shows an exploded view of the casing 5 at end 15b with cap 20c removed and cap 20d in position on the device. The liquid entry port 40 is shown ready to receive a tube 45 comprising a flange 55, having a sharp edge 57. The exterior diameter of the tube is approximately 3 mm and the diameter of the flange is approximately 8 mm. When inserted into the liquid entry port 40, the exterior surface of the tube 45 forms a sealing relationship with the interior surface of the port 40, so that water can only progress through the port 40 via the mouth 50 of the tube 45. The internal diameter of the tube is approximately 2 mm. The tube 45 is inserted into the port 40 such that the lower surface 60 of the flange 55 does not make contact with the inclined section 35b (or the neighbouring surfaces 35a and 35c). Therefore, a space is maintained under the flange surface 60, between the material of the flange 55 and the surface 35b, so that water may be present in this space without the possibility of surface tension causing water to progress up to the mouth 50 of the tube 45, where it could enter the interior of the casing 5 via the port 40. In the particular embodiment described here, there is typically approximately 3 mm between the surface 35b and the flange surface 60.
(13) The cap 20c has an edge 65, comprising a curved edge 70 and a linear edge 75 (see also FIG. 4A). The linear edge 75 is joined to the curved edge 70 by joining edge 80. Equivalent edges on cap 20d are also indicated in FIG. 3. When the edge 65 of the cap 20c is in contact with the exterior surface of the casing end region, a sealing relationship is formed so that water may not readily access the mouth 50 of the tube 45 extending through the liquid entry port 40. The dotted line 85 in FIG. 2 is a schematic indication of the exterior surface of the cap 20c when sealingly engaged in position, defining the cap space 90 between the exterior surface of the casing end region and the interior surface of the cap. The maximum distance between the interior surface of the cap and the surface 35b is approximately 10 mm. The internal volume of the cap space, in the embodiment described here, is typically less than about 2 ml.
(14) The features marked 110 in FIGS. 2 and 3 are fixing points to enable sealing engagement between the cap and the casing end region. These may be fixing means such as a screw engaged from the outside of the cap through to the material forming the casing end region, or may be a simple clip feature such as shown in FIG. 3, in which a protrusion 110 from the material forming the casing end region may frictionally engage with an engagement feature 112 such as a recess formed in the interior material of the cap (see FIG. 5).
(15) In FIGS. 1, 2 and 3, flow apertures may be observed on caps 20c and 20d, with end apertures 95, side aperture 100 and top aperture 105. Aperture 100 is formed at the edge of the cap, in joining edge 80, which engages with the surface 35b. Such an aperture is formed on both sides of the cap, as shown in FIG. 4A. The relative positioning of the various apertures ensures that, not matter what the orientation of the device, there is always at least one aperture positioned such that water may flow under gravity out of the cap space. The inventor has found this arrangement of five flow apertures to be optimal for achieving this.
(16) FIGS. 4A and 4B show exterior views of the cap. The curved edge 70, linear edge 75 and joining edges 80, together forming cap edge 65, may be observed, with apertures 95, 100 and 105 formed as recesses in the edge of the cap. The recesses are approximately 3-4 mm across and approximately 1 mm deep. When the cap is positioned so that the edge 65 contacts the exterior surface of the casing end region, the flow apertures are completed. The curved edge 70 makes contact with the curved perimeter 36 of the surface 35a. The joining edge 80 makes contact with the side 37 of surface 25b. The linear edge 75 makes contact with the casing exterior edge 38 of the surface 35c, at the region shown schematically by xxx in FIG. 2.
(17) In an alternative embodiment not illustrated here, surfaces 35a, 35b and 35c may each or all form a concave curve, in which case the shape and dimensions of the cap edge 65 may be adjusted accordingly. In one example, surface 35c may remain as shown, but surfaces 35a and 35b may form a single concave curve. Likewise, an arrangement involving one or more convex curves may be contemplated. Variations to the exact arrangement of this region of the device may be contemplated by the skilled person and are not critical to the working of the invention.
(18) FIG. 5 shows the structure of the interior of a cap. The interior surface 115 of the cap is generally formed as a smooth, curved surface, to reduce dew points on which water may gather. This view of the cap interior shows ridges 120a and 120b, each extending between the edge of the aperture 105 and one of the apertures 95. The top surface 125 of each ridge is formed as a convex curve relative to the longitudinal axis of the ridge, this shape assisting in encouraging water to move towards one end or the other of the ridge (depending on the orientation of the device) and then to exit the cap space via the aperture at the end of the ridge. Each ridge has a thickness of approximately 0.5-1 mm and a maximum depth of approximately 2-3 mm. The inventor has found that the presence of the ridges greatly encourages the egress of water which has entered the cap space as a result of splashing or of heavy rain landing on the device, such that water does not build up in the cap space to enter the tube 45 via the tube mouth 50. Water entry into the interior of the casing 5 is thereby discouraged.
(19) FIG. 5 also enables visualisation of the funnel structure of the flow apertures 95, 100 and 105. For example, at the bottom left of FIG. 5, it can be seen that the aperture 100 is formed such that the cross-sectional area of the aperture opening at the interior surface is greater than the cross-sectional area of the aperture opening at the exterior surface. Therefore, the aperture forms a funnel having a larger mouth at the interior of the cap compared to the mouth at the exterior. This feature makes it more difficult for water to enter than to leave the cap interior. By this method, any water present in the cap interior is encouraged to leave via a flow aperture.
(20) FIG. 6 shows a portion of the interior construction of the casing 5, with casing halves 10a and 10b defining the interior 130. T-bars 135a and 135b are forced together in the direction of the arrows A by the action of the PVA string 140 which binds the T-bars together. This counteracts the effect of the spring 145 which is positioned between casing halves 10a and 10b and is tensioned so as to tend to force the halves apart in the direction of the arrows B; this movement is, therefore, prevented so long as the force in the direction of the arrows A is maintained by the presence of the PVA string 140. Screw 25 extends into T-bar 135a from the exterior of casing half 10a, to enable assembly of the device with the PVA string intact.
(21) When water is able to enter the interior 130 in the direction of the arrows C, via the tube 45 which extends through the entry port 40 (shown with the tube present for the casing half 10a and with the tube absent for the casing half 10b), the relative location of the tube 45, the T-bar 135a and the PVA string 140 has the effect that water is directed to make contact with the string. On contact with water, the string dissolves, enabling the action of the spring 145 to force the casing halves 10a and 10b apart in the direction of the arrows B. This releases any item(s) which may be packaged or contained in the interior 130, or in some trigger arrangements, may activate an alarm. For example, an electrical contact may be maintained between the adjoining surfaces of the T-bars 135a and 135b such that, when the electrical contact is broken, a digital signal is generated for communication with an exterior detection device. The forcing apart of the casing halves 10a and 10b would cause such a break in this electrical contact, notifying the detection device that water has entered the interior of the device; this may, for example, trigger an alarm.
(22) The presence of the various features within the device shown in FIGS. 1-6 has the effect described as follows. Water is generally unable to enter the interior of the device casing, which contains the water-activated trigger (such as a casing destruction mechanism as described in FIG. 6). The only access point for water is via the tube 45 located in the port 40. In order to ensure that the trigger is not activated when the device is heavily splashed, or contacted with heavy rain, but is only activated when the device is submerged, various features act to either discourage the entry of water into the casing interior, or to encourage exit of water from the cap space.
(23) The entry of water into the casing interior is made more difficult by the presence of the tube 45 extending through the port 40. This means that water must access the tube mouth 50 before being able to enter the port 40, rather than being able to trickle down through the port 40. The further addition of the flange or ring 55, positioned so that there is a gap between its underside 60 and the device surface 35b, provides a further hurdle which any water must overcome before it may enter the mouth 50 of the tube 45. The presence of the flange 55 and tube 45 encourages any water present to spread out across the surface 35b, rather than entering the port 40.
(24) The presence of the apertures 95, 100 and 105 enables any such water gathering in the cap space to leave the cap space under the action of gravity, regardless of the orientation of the device. If the device is in the orientation shown in FIG. 3, for example, water may exit via apertures 95 and 100 in the cap 20c, or from aperture 105 in cap 20d (not visible in this Figure). If the device is turned so that an end is directed downwards, water may exit via apertures 95. In intermediate directions, water may exit via a combination of apertures depending on the action of gravity and any surface tension which may cause small amounts of water to coalesce. The interior surface of the cap being formed as a concave curve assists with encouraging water to collect at the locations closest to the apertures and the apertures are positioned to take advantage of this. Furthermore, the presence of the ridges on the interior surface of the cap further serves to encourage any water present to move towards one or more apertures. Finally, the funnel shape of the apertures, with the exterior mouth smaller than the interior mouth, makes it more difficult for splashed water or rain to enter the cap space in the first place, whilst also making it easier for any water which is present in the cap space to leave.
(25) If the tube 45 is orientated so that it is positioned vertically, with the tube mouth 50 directed downwards, the vertical distance between the mouth 50 of the tube and the interior surface of the cap 20 is the smallest possible. Therefore, in this orientation, it is more likely for water to be present in the cap interior to a depth to contact the mouth 50 of the tube. However, the tube 45 is dimensioned such that upwards entry of water through the mouth 50 of the tube as a result of capillary action is not possible, so that water cannot enter unless the tube 45 is moved towards the horizontal position (or the device is so inundated with water by immersion that the features discouraging water entry are overwhelmed). As the orientation of the device moves the tube 45 toward the horizontal position, water flows away from the mouth 50 of the tube into the other regions of the cap, quickly draining from the ports 95, 100 and 105.
(26) These combined features prevent or reduce the occurrence of water entering the casing interior unless and until at least a casing end region, if not the whole device, is immersed in water. This effect has been demonstrated on repeated occasions by the inventor. The pressure from immersion in water overcomes the effect of the various features described above and swamps the cap space, thereby enabling water to access the mouth 50 of the tube 45 and so to enter the casing interior via the port 40. This enables the activation of the liquid-activated trigger located within the casing, for example, as described above in relation to the embodiment shown in FIG. 6.
(27) FIG. 7 shows a device 200 as described in WO2016/020649 in position within a lifejacket 205. The attached packaged lifting line 210 and lifting ring 215 are shown attached to a device 1 according to the present invention, as shown in FIGS. 1-6, the device also comprising the target mesh element within the interior of the device casing, which is deployed so that a rescuer can make safe contact with a man overboard victim. The device 200 is secured to the lifejacket by an end of the lifting line at point 220.
(28) FIG. 8 provides a schematic representation of a flood alert system comprising a device as described herein. A river 300 may be enclosed by a bank 305 having a top surface 310. Such a bank may have a traditional depth indicator 315 fixed to it, to provide a visual indication of whether the surface 320 of the river 300 is rising in the direction of the arrow D. However, such indicators to not provide any automatic signal to authorities to alert them to a rising river and this may be of particular interest, for example, at night or on waterways prone to rapid and catastrophic flooding. Therefore, one or more devices 1 according to this invention may also be positioned at one or more positions on the bank 305. Lowest positioned device 1a may provide an alert when the surface 320 of the river 300 starts to rise in the direction of arrow D, with the next positioned device 1b providing an indication of a more dangerous depth change and the topmost positioned device 1c providing a warning of an imminent catastrophic flood which may cause the river to burst its banks. In the case of a rapidly developing flood, such a system may assist authorities in preparing surrounding communities and/or to evacuate people from the area. In such an arrangement, the interior of the casing of each device 1 comprises a system which is activated on activation of the liquid-activated trigger, this system being, for example, an audible alarm or a digital signal which is transmitted to an alarm system 325. Such a digitally-based system might be especially useful in more remote and/or poorer parts of the world, where the ability to notify central authorities to an unfolding flood event, without any requirement for sophisticated or expensive equipment, might be highly beneficial. The device 1 may comprise one or more solar cells on an exterior surface, to provide power to a means for generating a required digital signal, on activation of the trigger.
