The present invention relates to a drainage bowl with a resilient bi-stable diaphragm member, for use particularly, but not exclusively, as a closable colander.

Colanders are widely used in the preparation of food which is cooked in a cooking liquid, such as boiling water. Once cooked the food and water are poured into a colander and the cooking liquid is allowed to drain therefrom, leaving the food to be further prepared or served.

One drawback with traditional colanders is that the food must be transferred therefrom to another container for further preparation or for serving, because food or further cooking liquid can continue to drain from the drainage apertures for some time. This adds to the food preparation time, and is inconvenient.

Another problem with known colanders is that they are often placed in a sink for use, which can locate them at an awkwardly height. To solve this problem some colanders are provided with a foot to raise them off any surface, however this makes such colanders harder to store because they are larger in size.

A different kind of drainage problem is encountered with some plants which thrive on regular transient watering. Known plant pots for these kinds of plants comprise apertures which allow water to drain therefrom after it has been poured into the soil and has passed over the roots of the plant. However, these kinds of pots are only appropriate for an outdoor setting as they obviously leak. If a water tight pot is used with such a plant housed indoors, the plant can suffer because it is subjected to too much water for too long.

The present invention is intended to overcome some of the above described problems.

Therefore, according to the present invention, a bowl comprises an open top, an outer surface and a base, in which a plurality of first drainage apertures are provided in said outer surface, in which said base is provided with a resilient bi-stable diaphragm member which is manually switchable between a first dome configuration in which it extends away from said outer surface, and a second dome configuration in which it is everted in relation to said first configuration and overlies said outer surface to close said plurality of first drainage apertures. Thus, the present invention provides a colander or plant pot with drainage apertures which can be opened and closed in a quick and easy manner by flipping the resilient diaphragm member between its two configurations.

The use of a resilient bi-stable evertable member has a number of advantages. Firstly, as the diaphragm member is stable in its two different dome configurations it will remain static in those configurations until sufficient external influence is applied. Secondly, once sufficient force has been applied to flex the diaphragm member past the point at which it will return to one dome configuration, it will automatically move quickly into its opposite dome configuration. This is advantageous because the drainage apertures can be closed quickly and with a degree of resilient spring force.

It is possible for the outer surface of the bowl to define an area which is equal to, or lesser in volume than a volume defined by the diaphragm member when in its second dome configuration. This would mean that the diaphragm member is a snug, or loose fit over the outer surface. However, in a preferred construction the outer surface can instead define an area which is greater in volume than a volume defined by the diaphragm member when in its natural second dome configuration. (The term "natural second dome configuration" is intended to refer to the stable shape the diaphragm member would assume if not mounted to the bowl. Of course, when it is attached to the bowl it never achieves this shape, as it is prevented from doing so by the outer surface.) This arrangement means that a degree of resilient force will be exerted by the diaphragm member against the outer surface, thereby closing the drainage apertures effectively.

When the diaphragm member is in its first dome configuration it can form a useful foot upon which the colander or plant pot can sit. In particular, with a colander it can be placed in a sink and the diaphragm member will hold it above the base of the sink. When liquid drains from the colander in use it will pass through the drainage apertures and out onto the surface of the diaphragm member, which will direct it down and away to the base of the sink.

It will be appreciated that the diaphragm member could be switched between its two configurations by means of direct manual manipulation, however preferably the bowl can comprise an outer rim which defines the open top, and a pair of diametrically opposed handles can be formed on said outer rim, which can be used to apply downward pressure in use to flip the diaphragm member from its first dome configuration to its second. Therefore, once a colander has drained in a sink the user need only apply downward pressure to the handles to evert the diaphragm member and close the drainage holes. The bowl can then be transferred to another surface for the food to be further prepared, or served.

It will also be appreciated that a diaphragm member which can evert in this manner can have any general shape, and in one version of the invention the diaphragm member can be annular.

However, a particular problem may arise with an annular diaphragm member if the bowl is used as a colander. In particular, if the diaphragm member is placed on a planar surface, and hot cooking liquid then drains onto the diaphragm member in use, this can cause it to expand and create suction onto the planar surface. To avoid this the diaphragm member can comprise an outer rim with at least one concavity formed therein, such that when the diaphragm member is in the first dome configuration a first portion of the outer rim extends through a first plane, and a second portion of said outer rim extends through a second plane different to the first plane. Therefore, if the diaphragm member is placed on a planar surface at least one gap is provided around the outer rim, which prevents the creation of any negative pressure thereunder in use. Preferably a plurality of spaced gaps like this are provided.

Liquid can drain from any aperture in a colander or similar device, but it will tend to drain from the bottom thereof. Therefore, in one embodiment of the invention the outer surface can comprises a plurality of second drainage apertures positioned further from the base that the plurality of first drainage apertures , and in the second dome configuration an outer rim of said diaphragm member can be disposed between the first drainage apertures and the second drainage apertures, so the second drainage apertures remain open.

The bowl of the present invention can be manufactured from any suitable materials, and using any suitable techniques. The only requirement is that the diaphragm member be physically capable of operating in the manner described above. It has been found that silicone is a suitable material from which to construct the diaphragm member, but it could also be made from any plastics materials such as polyurethane, or from any rubber material. If the bowl is to be used in the preparation and serving of food, then any silicone material used would have to be food-grade. This would not be necessary if the bowl was only for use as a plant pot. The main body of the bowl can be made from any known plastics or metal material.

The diaphragm member can be affixed to the base of the bowl using any suitable means, but in one version of the invention the base can comprise a mounting aperture, and the diaphragm member can comprise a plug section which is a push-fit into said mounting aperture. Alternatively, the outer surface can comprise a mounting aperture at the base, the diaphragm member can comprise a central opening which is aligned with the mounting aperture, and the bowl can comprise a clamp member which passes through the central opening and can be affixed in the mounting aperture. The clamp member can comprise a flange section which retains the diaphragm member. The clamp member can be affixed in the mounting aperture in any known way, such as with bolts or rivets, by means of a resistance fit, or by means of a screw thread.

In one version of the invention the diaphragm member can comprise an internal spring steel member comprising a central portion aligned with a centre of the diaphragm member , and plurality of spring arms extending radially away from said central portion. This construction provides the diaphragm member with a more robust everting characteristic, as the spring steel assists the movement.

In another version of the invention the diaphragm member can comprise a substantially annular hinge formed therein comprising a section of silicone material

narrower than the remainder of the diaphragm member. The use of such a hinge helps the diaphragm member to move between its two dome configurations, and it also provides a degree of stability to the first dome configuration, when the diaphragm member may be used to support the bowl above it.

In addition, it has been found that in some situations the diaphragm member may flip into its second dome configuration with sufficient force to eject liquid in the vicinity of any of the first drainage apertures upwards. If the bowl is used as a colander this could mean that hot cooking liquid is ejected towards the user pushing down on it.

Therefore, in another version of the invention the diaphragm member can comprise a polar axis and a radial axis which intersects said outer rim at first and second opposite circumferential points. At a cross-section passing through the diaphragm member which is aligned with the radial axis the diaphragm member can comprise a first part on one side of the polar axis which has a greater thickness than a second part on the opposite side of the polar axis. Further, the thickness of the diaphragm member can decrease linearly in a circumferential direction from the first part to the second part, in both circumferential directions therefrom. With this arrangement the force required to flex the diaphragm member at the first part past the point it will then evert automatically is greater than the force required to flex the diaphragm member at the second part past the same point, as it is thinner and therefore more flexible. The force required decreases linearly around the outer rim from the first part to the second. This means that if a user exerts equal downward pressure on the handles in use the diaphragm member will evert first at the second part, and it will then continue to do so around the opposite sides of the diaphragm member round to the first part. It essentially rolls circumferentially from one side to the other rather than flipping up in one upward movement. This rolling motion helps to prevent the diaphragm member from ejecting any cooking liquid in the vicinity of the draining apertures in an upward direction.

Another way to address the issue of liquid being ejected upwards when the diaphragm member is everted from the first dome configuration to the second, is to improve the drainage of liquid from the surface of the diaphragm member itself. The less liquid present on the diaphragm member the less likely that any will be ejected upwards. Improving the drainage also improves the general efficiency of the colander.

Therefore, in one embodiment the diaphragm member can comprise a plurality of radially extending rib cavities formed in a first surface thereof, said first surface being that which forms an exterior of said diaphragm member when it is in said first dome configuration. With this feature, when the liquid leaves the colander and lands on the diaphragm member it collects in the rib cavities on the exterior thereof, from where it is effectively drained away.

In an alternative embodiment the diaphragm member can comprise a polar axis and an outer rim, and a thickness of said diaphragm member can increase in a radial direction from said polar axis to said outer rim. Wth this arrangement, when the diaphragm member is in the first dome configuration a portion adjacent to the outer rim inclines inwardly, to give the bottom of the diaphragm member a slightly more rounded shape. It does this because the extra material adjacent to the outer rim renders it slightly less resilient, and slightly less inclined to evert. As such, the liquid drains away from the bottom of the diaphragm member more effectively because of its rounded shape.

Furthermore, it has also been found that in some situations the diaphragm member is resistant to the everting action generally. Therefore, in another embodiment of the present invention the diaphragm member can comprise a polar axis, and an annular cavity which is axially aligned with said polar axis. This annular cavity divides the diaphragm member into two sections with a ring of greater flexibility between them, and as a result when pressure is applied to the diaphragm member in use these two sections collapse in relation to one another as the diaphragm member everts from one dome configuration to the other. This makes the diaphragm member easier to manually manipulate, and it also serves to prevent it from ejecting liquid upwards in the manner described above, as the movement from the first dome configuration to the second is less sudden.

Preferably the diaphragm member can comprise a plurality of these annular cavities. They can be aligned with the polar axis, and a first set of cavities of different circumferences can be provided in a first surface of the diaphragm member, and a second set which correspond in position and size to the first set can be provided in a second surface of said diaphragm member. These annular cavities divide the diaphragm member into a plurality of toroidal sections with rings of greater flexibility between them, and as a result when pressure is applied to the diaphragm member in use these toroidal sections collapse in relation to one another as the diaphragm member everts from one dome configuration to the other. This makes the diaphragm member even easier to manually manipulate, and it again serves to prevent it from ejecting liquid upwards in the manner described above, as the movement from the first dome configuration to the second is even less sudden.

In any of the versions of the invention described above, a lid can be provided to close the open top of the bowl. This can be in order to seal an interior of the bowl when the diaphragm member is in its second dome configuration, so any contents can be preserved for a longer period of time, for example a number of hours or days, and/or it can also be to simply overlie the open top of the bowl in a non-sealed manner to best preserve the any contents for a shorter period of time, for example between preparation of food and then serving it.

So, preferably the bowl can further comprise a lid adapted to close the open top, which can comprise a first side, a second side, a peripheral rim and a resilient flange member which can extend from the peripheral rim. In a first closed position of the lid, it can be disposed in the open top with the first side uppermost and with the resilient flange member placed under compression against an interior surface portion of the bowl, thereby forming a seal. In order to place the lid in its first closed position it would simply be necessary to apply a light manual downward pressure in order to place the resilient flange member under the required

compression to form the seal. In a preferred embodiment, the resilient flange member can be formed such that when it is under no compression it extends from the peripheral rim at an angle which is less than 180 degrees to a plane of the first side. The resilient flange member can then comprise at least one aperture formed therein, which can extend from an outer edge thereof to a point spaced from the peripheral rim. In a second closed position of the lid, it can be disposed in the open top with the second side uppermost, and with the outer edge of the resilient flange member resting against the interior surface portion of the bowl, and with the at least one aperture forming an opening into an interior of the bowl.

This arrangement provides a versatile lid which can either seal the open top of the bowl by being placed therein with the resilient flange member biased against the interior surface portion, or which can be turned the other way up to loosely close the open top of the bowl. The at least one aperture, of which there are preferably two, provides a means by which an implement such a serving spoon can be placed inside the bowl with its handle extending through the opening formed by the aperture while the lid is in its second position. The provision of the at least one aperture does not affect the ability of the resilient flange member to seal the open top when the lid is in the first closed position, because the aperture does not extend the full width of the resilient flange member.

The lid can be constructed from a resilient silicone material, and it can have a handle on both the first side and the second side to allow for its ready manual manipulation.

The invention can be performed in various ways, but nine embodiments will now be described by way of example and with reference to the accompanying drawings, in which:

Figure 1 is a side view of a first bowl according to the invention in which a diaphragm member part thereof is arranged in a first dome configuration;

Figure 2 is a side view of the bowl shown in Figure 1 , in which the diaphragm member part thereof is arranged in a second dome configuration;

Figure 3 is a bottom view of the bowl shown in Figure 1 , in which the diaphragm member part thereof is arranged in the second dome configuration;

Figure 4 is a perspective view of the bowl shown in Figure 1 , in which the diaphragm member part thereof is arranged in the first dome configuration; Figure 5 is an exploded side view of the bowl shown in Figure 1 , in which the diaphragm member part thereof is shown in cross-section;

Figure 6 is an exploded side view of a second bowl according to the present invention;

Figure 7 is a partial cross-sectional side view of the bowl shown in Figure 6, in which a diaphragm member part thereof is arranged in a second dome configuration;

Figure 8 is a diagrammatic perspective view of a diaphragm member part of a third bowl according to the present invention;

Figure 9 is an in-use side view of the bowl shown in Figure 1 , in which the diaphragm member part thereof is arranged in the first dome configuration;

Figure 10 is an in-use side view of the bowl shown in Figure 1 , in which the diaphragm member part thereof is arranged in the second dome configuration;

Figure 1 1 is a cross-sectional side view of a diaphragm member part of a fourth bowl according to the present invention;

Figure 12 is a top view of the diaphragm member part shown in Figure 11.

Figure 13 is a perspective view of a diaphragm member part of a fifth bowl according to the present invention;

Figure 14 is a cross-sectional side view of a diaphragm member part of a sixth bowl according to the present invention;

Figure 15 is a side view of the sixth bowl according to the present invention;

Figure 16 is a cross-sectional side view of a diaphragm member part of a seventh bowl according to the present invention;

Figure 17 is a perspective view of a diaphragm member part of the seventh bowl according to the present invention; Figure 18 is a perspective view of an eighth bowl according to the present invention;

Figure 19 is a cross-sectional side view of a ninth bowl according to the present invention in which a lid part thereof is arranged in a first closed position;

Figure 20 is a perspective view of the bowl as shown in Figure 19;

Figure 21 is a cross-sectional side view of the bowl shown in Figure 19 in which said lid part thereof is arranged in a second closed position; and

Figure 22 is a perspective view of the bowl as shown in Figure 21.

As shown in Figures 1 and 2, a bowl, in the form of colander 1 , comprises an open top 2, an outer surface 3 and a base 4, in which a plurality of first drainage apertures 5 are provided in said outer surface 3, in which said base 4 is provided with a resilient bi-stable diaphragm member 6 which is manually switchable between a first dome configuration, as shown in Figure 1 , in which it extends away from said outer surface 3, and a second dome configuration, as shown in Figure 2, in which it is everted in relation to said first configuration and overlies said outer surface 3 to close said plurality of first drainage apertures 5.

In this embodiment the colander 1 is constructed from a metal material, and the diaphragm member 6 is constructed from a resilient food-grade silicone material. The colander 1 comprises an outer rim 7, which defines the open top 2. A pair of diametrically opposed handles 8 are formed on the outer rim 7, which can be used to apply downward pressure in use to flip the diaphragm member 6 from its first dome configuration as shown in Figure 1 , to its second dome configuration as shown in Figure 2.

As is clear from Figures 1 to 5, the diaphragm member 6 has a generally annular shape, but it has four equally spaced concavities 9 formed in an outer rim 10 thereof. As such, said outer rim 10 has a slightly undulating shape when the diaphragm member 6 is arranged in the second configuration, as shown in Figure 2. In addition, when the diaphragm member 6 is in the first dome configuration, as shown in Figures 1 and 4, first portions 11 of the outer rim 10 extend through a first plane 12, and second portions 13 of said outer rim 10 extend through a second plane 14 different to the first plane 12. Therefore, if the diaphragm member 6 is placed on a planar surface gaps 15 are provided around the outer rim 10, which prevents the creation of any negative pressure thereunder in use. This could otherwise occur if the diaphragm member 6 were placed on a planar surface, and hot cooking liquid then drained onto the diaphragm member 6 in use, which caused it to expand and create suction onto the planar surface.

Referring to Figure 5, the base 4 comprises a mounting aperture 16, and the diaphragm member 6 comprises a plug section 17 which is a push fit into the mounting aperture 16. The plug section 17 has a mushroom-shaped cross section defining a head part 18 and a neck part 19. The head part 18 has a greater diameter than the mounting aperture 16, so when it is forced therethrough it serves to retain the diaphragm member 6 in place.

As is also shown in Figure 5, the diaphragm member 6 comprises a substantially annular hinge 20 formed therein, comprising a section of silicone material narrower than the remainder of the diaphragm member 6. The use of such a hinge helps the diaphragm member 6 to move between its two dome configurations, and it also provides a degree of stability to the first dome configuration, when the diaphragm member 6 may be used to support the colander 1 above it.

The outer surface 3 in this embodiment defines an area which is greater in volume than a volume defined by the diaphragm member 6 when in its natural second dome configuration, were it not mounted to the bowl. Of course, when it is attached to the bowl as shown in the Figures, it never achieves this shape as it is prevented from fully doing so by the outer surface 3. However, this arrangement means that a degree of resilient force is exerted by the

diaphragm member 6 against the outer surface 3, thereby to close the drainage apertures 5 effectively.

Therefore in use a user arranges the diaphragm member 6 into the first dome

configuration as shown in Figures 1 and 4, and places the colander 1 in a sink, or on a drainer or the like. In this position the diaphragm member 6 forms a useful foot upon which the colander 1 sits, thereby raising it to a useful height for the user to readily access. As a result of the concavities 9 formed in the outer rim 10 of the diaphragm member 6, no seal can be created between it and a planar surface upon which it rests, which could otherwise facilitate suction. As the diaphragm member 6 is bi-stable it remains static in this first dome configuration, even if a degree of force is applied. However, as the diaphragm member 6 is resilient, if some force is applied it will flex. As such any small inadvertent impacts will be absorbed. In addition, should a user wish to tilt the colander 1 in a particular direction, for example if a heavy load is applied to one side, the diaphragm member 6 will provide for this. The user then places their cooked food into the colander 1 and allows the cooking liquid to drain through the drainage apertures 5. The liquid passes through the drainage apertures 5 and down the diaphragm member 6, into the sink or onto the drainer.

When the draining is complete the user exerts downward pressure on the two handles 8. This needs to be done with sufficient force to flex the diaphragm member 6 past the point at which it would return to its first dome configuration, so it will then move quickly into its opposite second dome configuration, as shown in Figures 2 and 3, in which it closes the drainage apertures 5. This is advantageous because the drainage apertures 5 are closed quickly and with a degree of resilient spring force.

As the outer surface 3 defines an area which is greater in volume than a volume defined by the diaphragm member 6 when in its natural second dome configuration, a degree of resilient force is also exerted by the diaphragm member 6 against the outer surface 3, thereby closing the drainage apertures 5 effectively.

The colander 1 can then be transferred to another surface for the drained food to be further prepared, or served.

After use the diaphragm member 6 can be manually manipulated to return the colander 1 to the arrangement shown in Figure 1 , for cleaning or for further use. Obviously the colander 1 is more readily stored with the diaphragm member 6 in its second dome configuration, as shown in Figures 2 and 3.

It will be appreciated that the device shown in Figures 1-5 does not only find application as a colander as described above. It can also be used to facilitate any draining process. For example, as shown in Figures 9 and 10, it can also be used to store and to water plants 21 of the kind which thrive on regular transient watering. With this use the diaphragm member 6 can be placed in its second dome configuration, in the manner described above, so it forms a liquid tight plant pot as shown in Figure 10. Soil can be placed therein, and the plants 21 planted. When the plants 21 require watering the diaphragm member 6 can be manually manipulated into its first dome configuration, as shown in Figure 9, and the plants 21 can be watered. The water can pass over the roots of the plant and then drain from the drainage apertures 5. When the watering process has completed the user can switch the diaphragm member 6 back to its first dome configuration in the manner described above, so no further water or soil will leak out. The embodiment shown in Figures 1-5 and 9-10 can be altered without departing from the scope of claim 1. For example, Figures 6 and 7 show a second colander 22 which operates in the same manner as colander 1 described above, but it has a few different features.

In particular, colander 22 comprises not only first drainage apertures 23, which are closed by diaphragm member 24 in the manner described above, but also a plurality of second drainage apertures 25, which are positioned further from the base 26 than the first drainage apertures 23. As a result of this, when the diaphragm member 24 is arranged in the second dome configuration the outer rim 27 thereof is disposed between the first drainage apertures 23 and the second drainage apertures 25, so the second drainage apertures 25 remain open. It will also be appreciated that the first and second drainage apertures 23 and 25 are of a different shape and configuration to drainage apertures 5 in colander 1.

This configuration of drainage apertures 23 and 25 allows for increased aeration of any food in the colander 22 once the diaphragm member 24 has been placed in the second dome configuration. It also provides an improved aesthetic appearance.

Diaphragm member 24 is also generally annular, like diaphragm member 6 described above, but it also comprises four equally spaced concavities 28, which are a different shape to those referred to above, but which perform the same function.

The manner in which the diaphragm member 24 is affixed to the colander 22 is also different to the arrangement of the first embodiment. In particular, referring to Figure 7, the outer surface 29 of the colander 22 comprises a mounting indentation 30 at the base 31 , the diaphragm member 24 comprises a central opening 32 which is aligned with the mounting indentation 30, and the colander 22 comprises a clamp member 33 which passes through the central opening 32 and is affixed in the mounting indentation 30. As is clear from Figure 6, the clamp member 33 is a metal cap provided with a flange section 34 at an outer end 35 thereof which retains the diaphragm member 18. The clamp member 33 is affixed in the mounting indentation in any known way. This could be with the use of bolts or rivets, by means of a resistance fit, or by means of a screw thread, none of which are shown. In each case the clamp member 33 can be removed in order to dismantle the colander 22 for cleaning (except if it is secured with rivets or the like which cannot be released).

In an alternative construction (not shown) the diaphragm member can comprise a central clamp member part which is integrally moulded with it. For example, if the diaphragm member is constructed from silicone, then a central section can be made from a plastics material, or a metal, and can be integrated into the part with using a dual-shot manufacturing process. The central clamp member part can be like clamp member 33 described above, and can affix to the colander 22 using any known means, such as a resistance fit, a screw thread, or bolts or rivets.

Figure 8 shows a diaphragm member 36 used in another embodiment of the invention. The diaphragm member 36 is for use with a colander like colander 1 described above, but it comprises an internal spring steel member 37 (shown in hashed lines) comprising a central portion 38 aligned with a centre 39 of the diaphragm member 36 and four equally spaced spring arms 40 extending radially away from said central portion 39. This construction provides the diaphragm member 36 with a more robust everting characteristic, as the spring steel assists the movement between the first and second dome configurations.

Figures 11 and 12 show a diaphragm member 41 used in another embodiment of the invention. The diaphragm member 41 is similar to diaphragm member 6 described above, but it has an additional feature. In particular, the diaphragm member 41 comprises a polar axis 42 and a radial axis 43 which intersects the outer rim 44 at first and second opposite

circumferential points 45 and 46. At the cross-section passing through the diaphragm member 41 which is aligned with the radial axis 43, which is the cross-section shown in Figure 11 , the diaphragm member 41 comprises a first part 47 on one side of the polar axis 42 which has a greater thickness than a second part 48 on the opposite side of the polar axis 42. As is clear from Figure 12, the thickness of the diaphragm member 47 decreases linearly in a

circumferential direction from said first part 47 (aligned with point 45) to said second part 48 (aligned with point 46), in both circumferential directions, indicated by arrows 49 and 50, therefrom.

With this arrangement the force required to flex the diaphragm member 41 at the first part 47past the point it will then evert is greater than the force required to flex the diaphragm member 41 at the second part 48, as it is thinner and therefore more flexible. The force required decreases linearly around the outer rim 44 from the first part 47 to the second 48, which means that if a user exerts equal downward pressure on the handles in use the diaphragm member 41 will evert first at the second part 48, and it will then continue to do so around the opposite sides of the diaphragm member 41 round to the first part 45. It essentially rolls circumferentially from one side to the other rather than flipping up in one upward movement. This rolling motion helps to prevent the diaphragm member 41 from ejecting any cooking liquid in the vicinity of the draining apertures in an upward direction in use. Figure 13 shows a diaphragm member 51 used in another embodiment of the invention. The diaphragm member 51 is similar to diaphragm member 6 described above, but it has an additional feature. In particular, the diaphragm member 51 comprises a plurality of rib cavities 52 on a first surface 53 thereof. The first surface 53 being the surface which is inside the diaphragm member 51 when it is in the second dome configuration, as shown in Figure 13, but which forms the exterior of the diaphragm member 51 when it is in the first dome configuration. The rib cavities extend from an outer rim 54 of the diaphragm member 51 most of the way to the plug section 55.

The purpose of the rib cavities 52 is to facilitate the drainage of cooking liquid from the colander when the diaphragm member 51 is in the first dome configuration. The liquid leaves the colander and collects in the rib cavities 52, from where it is effectively drained away. This improves the functionality of the colander because it drains more efficiently, and it also serves to prevent the occurrence of cooking liquid being ejected upwards when the diaphragm member 51 is everted from the first dome configuration to the second dome configuration in use, because less liquid remains on the diaphragm member 51.

Figures 14 and 15 show a diaphragm member 56 used in another embodiment of the invention. The diaphragm member 56 is similar to diaphragm member 6 described above, but it has an additional feature. In particular, the diaphragm member 56 comprises a polar axis 57 and an outer rim 58, and a thickness of the diaphragm member 56 increases in a radial direction from said polar axis 57 to said outer rim 58, as indicated by arrow 59. The increase in thickness towards the outer rim 58 is only small, but it has a material effect on the working of the diaphragm member 56.

In particular, when the diaphragm member 56 is in the first dome configuration as shown in Figure 15, a portion 60 adjacent to the outer rim 58 inclines inwardly, to give the bottom of the diaphragm member 56 a slightly more rounded shape. It does this because the extra material adjacent to the outer rim 58 renders it slightly less resilient, and slightly less inclined to evert.

The purpose of this diaphragm member shape is to facilitate the drainage of cooking liquid from the colander 61 when the diaphragm member 56 is in the first dome configuration. The liquid drains away from the bottom of the diaphragm member 56 more effectively because of its rounded shape. This improves the functionality of the colander 61 because it drains more efficiently, and it also serves to prevent the occurrence of cooking liquid being ejected upwards when the diaphragm member 56 is everted from the first dome configuration to the second dome configuration in use, because less liquid remains on the diaphragm member 56.

Figures 16 and 17 show a diaphragm member 62 used in another embodiment of the invention. The diaphragm member 62 is similar to diaphragm member 6 described above, but it has an additional feature. In particular, it is provided with a first set of annular cavities 63-65 in a first surface 66 thereof, and a second set of correspondingly positioned and sized annular cavities 67-69 in a second surface 70 thereof. These annular cavities 63-69 are all axially aligned with a polar axis 71 of the diaphragm member 62, and as is clear from Figures 16 and 17, the three opposed pairs 63 and 67, 64 and 68 and 65 and 69 are equally spaced between the polar axis 71 and an outer rim 72 of the diaphragm member 62. The annular cavities 63-69 are formed by creating wasted sections in the diaphragm member 62.

These annular cavities 63-69 divide the diaphragm member 62 into a central section 73, and three toroidal sections 74-76 with rings of greater flexibility between them. As a result when pressure is applied to the diaphragm member 62 in use the toroidal sections 74-76 collapse in relation to one another as the diaphragm member 62 everts from one dome configuration to the other. This makes the diaphragm member 62 easier to manually manipulate, and it also serves to prevent it from ejecting liquid upwards in the manner described above, as the movement from the first dome configuration to the second is less sudden.

Figure 18 shows an embodiment of the invention, in which colander 77 is the same as colander 1 described above, except that it is provided with a removable lid 78. The lid 78 add greater versatility to the colander 77, as prepared food can be drained, and then kept in a sealed container before being consumed. This helps to preserve the texture and heat of some foodstuffs prior to serving.

Figures 19 to 22 show a further embodiment of the invention, in which colander 80 is similar to colander 1 described above, except that it is provided with resilient silicone lid 81. The lid 81 comprises a first side 82, a second side 83, an annular peripheral rim 84 and an annular resilient flange member 85 which extends from the peripheral rim 84. As is clear from Figures 19 to 22, the resilient flange member 85 is formed such that it extends from the peripheral rim 84 at an angle which is less than 180 degrees to a plane A-A of the first side 82. The angle of the resilient flange member 85 is approximately 50 degrees to the plane A-A when the resilient flange member 85 is under no compression (as in Figures 21 and 22). The lid 81 also comprises handles 86 and 87 provided on the first and second sides 82 and 83 respectively, to allow for its ready manual manipulation.

As shown in Figure 19, the lid 81 can be placed in a first closed position, in which it is disposed in the open top 88 of the bowl 89, with the first side 82 uppermost and with the resilient flange member 85 placed under compression against an interior surface portion 90 of the bowl 89, thereby forming a seal. An exterior side 91 of the resilient flange member 85 creates the seal by forming a contact area with the interior surface portion 90. In order to place the lid 81 in its first closed position it is only necessary to apply a light manual downward pressure in order to place the resilient flange member 85 under the required compression to form the seal. This pressure can be applied via the handle 86. An annular wasted section 92 is provided on the lid 81 adjacent to the resilient flange 85, in order to facilitate the rotation of the resilient flange member 85 into the position shown in Figure 19.

If the lid 81 is placed in this first position when the diaphragm member 93 is in its second dome configuration, as shown in Figures 19 and 20, the interior 94 of the bowl 89 is completely sealed. This arrangement could be performed in order to preserve the contents of the bowl 89 for a longer period of time, for example a number of hours or days. As such, the sealing function of the lid 81 only has a purpose when used with a colander like colander 80 with drainage apertures 95 which can be sealed closed.

Referring to Figures 21 and 22, it can be seen that the resilient flange member 85 comprises two apertures 96 and 97 formed at opposite ends thereof. The apertures 96 and 97 each extend from an outer edge 98 of the resilient flange member 85 to a point 99 spaced from the peripheral rim 84. The lid 81 can be placed in a second closed position as shown in Figures 21 and 22, in which it is disposed in the open top 88 of the bowl 89 with the second side 83 uppermost, and with the outer edge 98 of the resilient flange member 85 resting against the interior surface portion 90 of the bowl 89. As shown in Figures 21 and 22, in this position the two apertures 96 and 97 form two openings, 100 and 101 respectively, into the interior 94 of the bowl 89. The openings 100 and 101 provide a means by which implements such a serving spoons (not shown) can be placed inside the bowl 89 with their handles extending through the openings 100 or 101 while the lid 81 is in its second position. With the lid 81 in the second position it only loosely overlies the open top 88 of the bowl 89 in a non-sealed manner, which best preserves any contents of the bowl 89 for a shorter period of time, for example between preparation of food and its serving. It will be appreciated that the apertures 96 and 97 do not affect the ability of the resilient flange member 85 to seal the open top 88 when the lid 81 is in the first closed position, because the apertures 96 and 97 do not extend the full width of the resilient flange member 85. This is clear from Figure 1 which demonstrates the seal being formed despite the presence of the apertures 96 and 97.

It will also be appreciated that a lid like lid 81 could be provided with any of the eight other embodiments of the invention described above, which would work to provide the same advantages.

In further embodiments of the invention (not shown) the bowl defines an area which is equal to, or lesser in volume than a volume defined by the diaphragm member when in its natural second dome configuration. This means that the diaphragm member is a snug, or loose fit over the outer surface.

In other embodiments of the invention (not shown) bowls comprise diaphragm members like diaphragm member 62, but with different numbers of pairs of annular cavities in the first and second surfaces thereof, including just one pair, two pairs or four or more.

It will be appreciated that the various features of the nine embodiments described above can be readily combined to create further embodiments. For example, in one further embodiment (not shown) a diaphragm member comprises the cross-sectional shape of diaphragm member 41 shown in Figures 11 and 12, as well as the rib cavities of diaphragm member 51 shown in Figure 13. In another embodiment (not shown) a diaphragm member comprises the cross-sectional shape of the diaphragm member 56 shown in Figures 14 and 15, as well as the central opening of the diaphragm member 24 shown in Figures 7 and 8. It will be appreciated that any such combination of features is possible, and is within the disclosure of this patent application.

Thus, the present invention provides a colander, plant pot or other device with drainage apertures which can be opened and closed in a quick and easy manner by flipping the resilient diaphragm member between its two dome configurations. There is also provided a lid for such a bowl which can seal the interior of the bowl shut in one arrangement, while allowing for a loose fit which can accommodate serving spoons or the like when used the other way up.