CA2530975A1 - Container with invertible mixing tray - Google Patents

Abstract

A multi-layer container for storing and mixing related items comprises a primary container having a body, an invertable mixing tray, and a lid. The primary container has an interior surface defining a cavity with an open top surrounded by a circumferential collar. The mixing tray has a tray peripheral flange and a rim integrally formed with a tray outer wall sized to be tightly nested in the cavity when arranged on the open top in a concave position.
The lid has sealing means for compressing said tray peripheral flange against said circumferential collar when the tray is in the concave position while preventing contact between items arranged in different layers during storage and transportation. Additionally, the rim is sized to snap fit in the open top when the tray is inverted and arranged in a concave position on the open top for increasing the volume of the primary container and allowing mixing.

Description

CONTAINER WITH INVERTIBLE MIXING TRAY
Field of Invention:
This invention is directed to containers in general and particularly to a multi-compartmented, multiple seal container with invertible mixing tray.
Background of the Invention:
Containers for separately transporting-storing and thereafter mixing contents, for example foodstuff with associated ingredients, are known in the art.
Usually, pre-measured portions of food are stored in separate compartments and conveniently mixed, reheated if necessary, and served. These containers are generally multi-compartmented, each compartment for storing one ingredient. The containers may be made of plastic, paperboard stock, or any light material that can hold the foodstuff. Environmentally friendly materials including re-usable containers, are now a priority in the industry.

US published application 2001/0030227, to Fear et al., discloses a composite container having a condiment container mounted on the external wall of the food container. Such combination formed by two containers appears to be bulky and provides insufficient protection to the condiment container. The same is true for the food containers disclosed in US published application 2003/0006274, to Lackner et al. Similarly, the multi-compartmented food containers made of paperboard or thin plastic as disclosed in US patent No.
5,423,449, to Gordon et al., and 5,335,845, to Liu, are not resistant enough to be used and re-used for school lunches or picnics.

In the food industry, it is often desirable to delay mixing of foodstuff with certain ingredients together until just prior to consumption, or to keep fruits from being immersed in own juice to slow deterioration of the quality. Food containers with barriers for dividing the interior of the container and separating the components are known and have constantly failed to provide environmental friendly, re-usable containers with improved separation of liquids from solids, while eliminating mixing implements, and avoiding spillage.

For example, the polymer-made disposable dinners are not environmental friendly and are gradually substituted by paper dinner sets. However, the paper dinner sets lack proper partitioning and are not leakproof or airtight due to cuts, or folds, and these factors prevent conventional food containers from having a large market share.

Fresh green salad is a very popular dish. Consumption of pre-prepared salads is increasingly popular not only for health reasons; it also saves the consumer time otherwise spend on washing the salad ingredients and preparing the dressing. In addition, it provides the consumers with a cost-saving solution. Thus, if the salad includes a plurality of vegetables (leafs of lettuce, radicchio, endives, cabbage, slices of carrots, etc) often times not the entire plant is used for one serving, and the reminder of ingredients is typically discarded after being kept for too a long time. A proper way for storing greens would be advantageously.

The salad dressings selection also evolved lately; it is possible now to buy low calories dressing varieties, spicy or sweet sauces using ethnic or proprietary recipes. As the recipes used by the food supply industry evolve for a more stylish taste, consumers are tempted to buy ready-to-use salad containers rather than preparing their own from greens sold in bowl-like containers with the dressing sold separately in small packets. Moreover, dressing packets are costly and inconvenient as they require significant dexterous manipulation to use.
It is therefore a need for a re-usable food container for storage and transport of a variety of food items in separate compartments preventing the taste of the food items from mixing with one another, and allowing mixing into a food dish when desired.
Summary of the Invention The present invention seeks to overcome the disadvantages of the prior art associated with containers. The invention will be described with reference to a food container but it is understood that the container of the invention having an invertible mixing tray may be used for storing, transporting and mixing any other related components forming the end-product.

According to one aspect of the invention, a multi-layer, multiple seal container, comprising a primary container, at least one invertible tray, and a lid is provided. The primary container has a bottom, upright lateral walls having an interior surface defining a cavity with an open top and a circumferential edge having an inverted-U shape defined around the open end. The circumferential edge includes a lip projecting outwardly from and in a plane perpendicular to the lateral wall exposing a lip open face. A skirt projects downwardly from and in a plane perpendicular to the lip.

The mixing tray has a channelled bottom, at least one un-tapered tray outer wall sized to be nested within the primary container, a plurality of compartments, and a central chamber defined around a separating wall centrally arranged in a middle region of the tray. The separating wall has an elevate rib, the plurality of compartments being arranged between spokes extending between the separating wall and the tray outer wall. The spokes have flat upper surfaces arranged in the tray levelling plane.
A rim integrally formed with the tray outer wall extends above the tray levelling plane. A peripheral flange defined in the tray levelling plane projects outwardly from the tray outer wall substantially perpendicular to the rim.

The lid has a peripheral ledge which includes a peripheral collar with a flat interior side, a sleeve extending downwardly from and in a plane perpendicular to the collar, and a channel defined adjacent to the collar on the lid internal face. A central well is defined on the lid external face in a middle region of the lid. The central well has a shape identical to the central chamber of the tray and is surrounded by a shoulder designed to match the contour of the tray elevate rib and forming the central cooperating sealing surfaces.

The tray flange, the flat interior side of the lid collar, and the lip open face have substantially same shapes and areas forming peripheral cooperating sealing surfaces disposed in a plane parallel to the tray levelling plane.

For assuming a store-transport state, the primary container tightly receives the mixing tray for closing the open end, such that the tray becomes nested inside the cavity of the primary container in a concave position. At the same time, the tray flange rests on the open face of the lip providing a second seal.
Thereafter, the lid is arranged on top of the tray, while the channel of the lid engages the rim on the tray for correctly positioning the lid on top of the tray.
When compressed, the lid brings into registry the peripheral and central cooperating sealing surfaces forming a compact, airtight container. Contact between items in different layers and compartments is prevented; contact is also avoided between liquid or semi-liquid items in the central chamber and items arranged in other compartments during transportation.

The tray includes two diametrally arranged spokes provided with indentations defining holding means on both sides of the mixing tray for, holding and inserting the mixing tray in the primary container in concave position in the store-transport position. For assuming a mixing position, the tray is lifted, inverted to a convex position, and the rim snapped fit in the open end of the primary container.

Related items are initially stored in the tray and in the primary container.
As mentioned above, the tray has a first set of holding means for positioning the tray in a concave position at a gravitational rest on top of the primary container, and for lifting the tray before inverting same. A second set of holding means may be provided on the bottom of the tray to arrange the tray in a convex position on top of the cavity, apply pressure to engage the rim at the open end of the primary container, and also disengage the mixing tray from the primary container after mixing.

A plastic food container according to the invention allows storage and transportation of a variety of liquids and granulated food items as well as the associated ingredients in separate layers and compartments, for either cold or hot-fill food packaging/serving. The food container is re-usable and suitable for lunch boxes, or storing half-prepared meals. The container allows separation of the related items as the compartments are airtight sealed such the components can not be accidentally mixed and prevents the taste of the food items from mixing with one another. The multi-component, multiple-seal container of the invention is airtight and microwavable . No conical sealing surfaces, no tapered walls are used and this allows to keep the manufacturing costs low while providing a container with an attractive design.
The "Summary of the Invention" section does not necessarily disclose all the inventive features. The invention may reside in a sub-combination of the disclosed features.

Brief description of the drawings The foregoing and other objects, features and advantages of the invention will be apparent from the following more particular description of the preferred embodiments, as illustrated in the appended drawings, where:

Figure 1 is a perspective view of the container with invertible mixing tray in store-transport state according to the invention;
Figure 2 is a lateral exploded view of the container of Figure 1;
Figure 3 is a top view of the container of Figure 1;
Figure 4 is sectional view of the container along line 4-4' of Figure 3;
Figure 5 is a top view of the invertible mixing tray;
Figure 6 is a perspective view of the container of Figure 1 with the invertible mixing tray nested in a concave position within the primary container in the store-transport position;
Figure 7 is a perspective view of the invertible mixing tray arranged in a convex position on top of the primary container in a mixing state; and Figure 8 is a flow chart illustrating a method of using the food container with invertible mixing tray according to the invention.

Similar references are used in different figures to denote similar components.

Description of the preferred embodiments The following description is of a preferred embodiment by way of example only and without limitation to combination of features necessary for carrying the invention into effect.
The container is now described with reference to Figures 1 to 7. The cylindrical food container 15 of this example is made of semi-rigid transparent plastic material and includes three major parts, namely, a lid 20, a mixing tray 30, and a primary container, in this example a bowl 40. The multi-compartment arrangement of the mixing tray 40 as well as a plurality of layers defined inside container 15 allows the food container 15 to carry different kinds of food in a tiered manner while combinations of food items into a food dish are possible whenever desired.

It is to be understood that a multi-layer container having a plurality of trays super-imposable on and engageable with the upper end of the tray below may be provided according to a tray-in-tray concept.

Bowl 40 has upright interior surfaces 45 defining a cavity with an open top and a bottom 43. As illustrated in the figures, the circumferential edge of the bowl 40 has an inverted-U shape with a perpendicularly outwardly projecting annular lip 38, extending from the bowl lateral wall 45 exposing a lip open face 38', and a circumferential skirt 29 extending downwards in a plane perpendicular to the plane of the annular lip 38.

Lid 20 has a bowed upper surface 19 with exterior and interior rounded edges 18',18", respectively, a peripheral ledge 47 adjacent to the lid exterior rounded edge 18', and a central well 14 adjacent to the lid interior rounded edge 18".
As best shown in Figure 4, lid 20 has a central well 14 defined in a middle region surrounded by the lid interior rounded wall 18" connected to a smaller radius circular wall 16 through an annular shoulder 17. Annular shoulder 17 is formed on the inner face of the lid 20 in a plane substantially perpendicular to the plane of the circular wall 16. A channel 36 is also provided on the inner face of the lid 20 adjacent to the exterior rounded edge 18', substantially perpendicular to the inner face of the lid 20.

The peripheral ledge 47 includes an annular collar 39 which projects outside in a plane perpendicular to the channel 36 and connects channel 36 with a peripheral sleeve 28 projecting downwardly in a plane perpendicular to the plane of the collar 39.

Mixing tray 30 has an intermittent un-tapered outer wall 44, tray compartments 33 and a cup-shaped partition wall 26" surrounding a central chamber 32. Partition wall 26" and outer wall 44 are connected through an elevate rib 26. As best shown in Figures 5 and 6, tray 30 includes spokes 21,22,25, defining compartments, or bins 33 on the tray upper side. As best shown in Figure 7, tray 30 has a channeled bottom 34.

Tray compartments 33 are defined between spokes 21, 22, 25, radialy extending between the partition wall 26" and the tray outer wall 44. The upper surfaces of spokes 21, 22, 25, are aligned in a tray leveling plane (P).
The elevate rib 26 extends slightly above the leveling plane (P) in a central region of the mixing tray 30. Rib 26 has a flat upper annular side 26' bridging the intermittent outer wall 44 and the partition wall 26". The central chamber 32, may be filled with liquids, or semi-liquids e.g. salad dressing. As mentioned before, mixing tray 30 includes a plurality of compartments 33 for receiving various ingredients at a gravity rest.

An annular flange 37 having an upper side 37' and an under side 37" projects outwardly in a plane perpendicular to the outer wall 44 slightly above the leveling plane (P). A rim 35 integrally formed with the outer wall 44 projects vertically from outer wall 44 above the tray leveling plane (P).

The invention partly resides in the unique design of container 15 having in this example, three parts cooperating for implementing seals Si to Ss. Groups of substantially vertical and horizontal sealing surfaces cooperate with corresponding surfaces defined either on lid 20, or on tray 30, and/or on bowl 40 for providing continuous perimetal sealing closures S1-S3, S2-S6, S4, and S5-S7, in a store-transport state, as well as sealing closure S8-S9 in a mixing state, as it will be later described. Sealing closures like for example S1-S3, S2-S6, S5-S7, or Ss-Ss are the result of a close association of two pairs of sealing surfaces positioned in two separate planes perpendicular along a common line. Each pair of sealing surfaces involves cooperating peripheral or central surfaces defined on the lid, tray, and bowl, respectively.

The store-transport state Bowl 40 and mixing tray 30 have sealing surfaces cooperating to provide airtight sealing closure S2-S6 formed whenever mixing tray 30 is nested in a concave position on top of bowl 40, best shown in Figure 6. Seal S2 is formed between the flange under side 37" rested on the lip open face 38'. The annular flange 37 and the annular lip 38 have substantially the same shape and identical areas. An additional seal S6 is formed between the interior upright surface of the bowl 45 and the exterior side of the un-tapered tray outer wall 44 whenever mixing tray 30 is concavely inserted in the bowl 40 in the store-transport state. As such, related items arranged in different layers in bowl 40 and tray 30 respectively, are separated during transportation.

The inventive design of the peripheral ledge 47 cooperates with the corresponding circumferential edge 48 of the bowl 40 to provide sealing closure S1-S3 as a result of a close association of two pairs of sealing surfaces defined on bowl 40 and on lid 20, respectively.

For closing the container 15, rim 35 is brought into registry with channel 36 on lid 20 for correctly positioning the lid 20 on top of tray 30. The mating areas defined on the peripheral sleeve 28 and circumferential skirt 29 have substantially the same dimensions, and are sized such that the peripheral sleeve 28 snaps fit on the circumferential skirt 29 when lid 20 is compressed against bowl 40 to provide seal Si. As lid 20 is further pressed against the tray 30, flat mating areas, namely, the upper side 37' of the annular flange and the inside face 39' of the annular collar 39 are brought into registry forming seal S3; seal S4 is formed at the same time between the vertically projecting rim 35 which is tightly received in channel 36 such that an airtight container arrangement is provided.

Concomitantly, when lid 20 is fully compressed against the mixing tray 30, the central well 14 on lid 20 acts as a cork on top of the central chamber 32 forming sealing closure S5-S7 as best shown in Figure 4. Seal S5 is formed by the flat upper annular side 26' of the rib 26 which contacts the annular shoulder 17 formed on the inner face of lid 20. At the same time, the partition wall 26" sealingly cooperates with the interior face of the wall 16 to provide seal S7.

As mentioned before, annular flange 37, annular collar 39, and annular lip 38 have substantially the same shape and identical areas. Annular flange 37 is tightly compressed between annular collar 39 and annular lip 38 to concomitantly provide sealing surfaces S2 and S3 when in the store-transport state. Even if mixing tray 30 is not present, seals Si and S3 are provided between collar 39 and lip 38 due to the particular design of the lid 20 and the flexibility of the semi-rigid plastic material.

When container 15 is completely closed and owing to rim 35 and channel 36 cooperation, the continuous perimetal sealing closures SI-S3, S2-S6 and S5-S7, are simultaneously provided. It is to be noted, that a continuous sealing edge is formed by each sealing closure that acts similar to an 0-ring for forming an airtight, unitary container 15 suitable for storage and transportation of related food items.

The description of the store-transport state was made using qualifiers like horizontal and vertical describing the container 15 when on a table in a "generally normal" position at a gravitational rest. This was done for easy understanding of the steps performed "by gravity" as for example, arranging the foodstuff in bowl 40, displaying ingredients in the compartments of the mixing tray 30, and for explaining the step of transferring the ingredients from tray 30 to bowl 40 also performed by gravity.

In any event, there are no constraints for the positioning of the container 15 during transportation due to the arrangement of the continuous perimetal sealing closures preventing spillage and mixing of food items arranged in different layers and compartments.

The mixing state Figure 6 is a perspective view of the invertible mixing tray 30 inserted in a concave position within the bowl 40 in the store-transport state. The mixing state is achieved by lifting, then inverting the mixing tray 30 and securing it to the bowl in a convex position as illustrated in Figure 7. In the mixing state, sealing closure S8-S9 is formed. Seal S8 is formed between the flange upper side 37' rested on the lip open face 38' of the annular lip 38; seal S9 is formed between the exterior side of the rim 35 snapped fit along the interior surface of the wall 45 of bowl 40. Again, the continuous perimetal sealing closure S8-S9 provides a sealed ridge that acts as an 0-ring between the inverted tray 30 and the bowl 40.

A first set of holding means may be provided on the top surface of the mixing tray 30 for example, two trapezoidal indentations 23,24, may be provided in diametrally opposite spokes 21,22, for disposing the tray 30 within the container in a concave position in the store-transport state, and lift, tilt, and transfer ingredients by gravity into the bowl 40 without spilling. A second set of holding means may be provided on the channeled bottom 34 to secure the inverted mixing tray 30 in a convex position on top of bowl 40 and for disengaging the mixing tray 30 from the bowl 40. The inverted mixing tray 30 is secured in a convex position on top of bowl 40 providing a leakproof enlarged container 15'.

Finally, tray 30 may be disengaged from bowl 40 by lifting, tilting, and repositioning the mixing tray 30 on the bowl 40 in a concave position as illustrated in Figure 6, using any means for manipulation provided on the mixing tray 30. It is to be noted that for example, the second set of holding means may be provided on the tray channeled bottom 34 as a complementary figure of the first set of holding means defined on the tray top side.

Method of using the container A method of using the inventive food container 15 according to the invention, is illustrated in Figure 8. The process starts at step 50. Food items are arranged by gravity in bowl 40 and in tray 30, step 51. In the compartments and in the central chamber 32, ingredients and salad dressing respectively, will be filled up to the leveling plane (P), if necessary. At step 52, mixing tray 30 is stored by gravity in a concave position in bowl 40. At step 53, container is sealed using lid 20 for compressing tray 30 against bowl 40 and assembling these three parts as a unitary airtight container.

To start eating, the lid 20 is removed on step 54 and the contents evaluated 15 on step 55. If no mixing is required, the process proceeds to step 60 where separate and compatible food items are served using the bowl 40 and the tray 30, and thereafter the process goes to step 61.

Alternatively, if mixing is required, at step 56, tray 30 is held with two fingers using indentations 23, 24, and tilted to transfer by gravity ingredients from tray into bowl 40. Further, tray 30 is inverted and secured on top of bowl 40 in a convex position at step 57, and the contents are mixed to prepare the food dish at step 58. Tray 30 is then removed and the food dish is served in bowl at step 59. Thereafter the process proceeds to step 61 where the mixing 25 tray 30 is re-positioned on top of the bowl 40 in a concave position and lid 20 used to restore the store-transport state. At step 62 the process ends.

A container according to the invention may be used for storing, transporting, and mixing any related items. In the example of Figure 1, the compact food 30 container 15 includes distinct layers for storing related food items, allows access to different compartments, and provides hermetic seals Si to Ss between layers and compartments.

It is to be understood that containers having more than two layers will still be within the scope of the invention and necessitate minor design alterations. In the example of Figure 1 a container with a cylindrical shape is illustrated but containers having different shapes like for example rectangular, triangular, semi-circular, hexagonal, are also within the scope of this invention.

The food container 15 may be made of any liquid-impervious molded thermoplastic material or polyester-coated paperboard or the like, suitable for the manufacture of containers adapted to store both cold and hot items and carry such items in a tiered manner allowing combination of food items into a food dish as and when desired. Advantageously, the container is transparent to see the contents, is reusable, and microwavable.

Preferably, container 15 is made of propylene by injection molding. Rough plastic resulting from an etching process during de-molding is used for esthetic reasons in pre-established areas on the interior surface 45 around the open end of the bowl 40, at the bottom 43 of the bowl 40, around the interior sides of the edges 18' and 39', and around the exterior sides of collar 39, channel 36, and edge 18'. Etched areas forming part of seals S1,S3, S5, S7, also increase friction and improve sealing.

A dial indicator 31 with a pointer rotates on a base inside the central well 14 to visibly indicate a day of the week, or the month, or the exact date of food entry. An annular ridge 46 is defined at the bottom of the bowl 40 for stable location of the bowl 40 on a horizontal surface. Two tabs 41, 42, are provided on bowl 40 for cooperating with tab 27 on lid 20 to facilitate opening of the container 15.

Numerous modifications, variations, and adaptations may be made to the particular embodiments of the invention without departing from the scope of the invention as defined in the claims. Reference to a claimed element in the singular is not intended to mean "one and only one" unless explicitly so stated, but rather "one or more". In other words, the articles "a" and "the"
do not suggest singularity unless it is evident from the specification that the patent intended only one element and includes numerous references to this single element.

List of parts 14 central well 15" enlarged container of Figure 7 16 lid inner wall 17 lid inner shoulder 18'18" exterior / interior lid rounded edges 19 bowed lid upper face 21,22,25 spokes 23,24 indentations 26 rib 26' flat upper annular side of the rib 26" partition wall 27 lid tab 28 circumferential sleeve 29 circumferential skirt 31 dial 32 central chamber 33 compartments, bins 34 tray (channeled) bottom 35 rim 36 channel 37 flange 37' flange upper side 37" flange under side 38 lip 38' lip open face 39 collar 39' collar interior side 41,42 tabs 43 primary container flat bottom 44 tray outer wall 45 primary container interior surface 46 ridge 47 peripheral ledge 48 circumferential edge S seals P tray leveling plane

Claims (17)

1. A container arrangement for storing related items, comprising:
a primary container having a container body with upright walls, an open top, and an interior surface defining a cavity, said open top having a circumferential edge with an inverted-U shape;
a tray having an un-tapered outer wall and a flange extending outwardly in a leveling plane substantially perpendicular to said outer wall, the outer wall sized to be tightly nested in said cavity when said tray is arranged on said open top in a concave position in a store-transport state; and a lid having a peripheral ledge, said peripheral ledge cooperating with said circumferential edge to provide an airtight sealed container arrangement preventing contact between items arranged in different layers in said store-transport state.

2. The container of claim 1, wherein said outer wall having a rim projecting outwardly and contiguous with said flange, said rim being sized to snap fit in said open top when said tray is inverted and arranged in a convex position in a mixing state.

3. The container of claim 1, wherein said peripheral ledge comprising a channel, a collar, and a sleeve, said circumferential edge comprising a lip and a skirt, said rim engaging said channel, said collar and said sleeve cooperating with said lip and said skirt, respectively, for firmly holding said flange in-between and sealing the container in said store-transport state.

4. The container of claim 1, wherein said mixing tray further comprising:
a central chamber defined around a partition wall in a middle region of the tray, said partition wall connected to said outer wall through an elevate rib extending slightly above said levelling plane; and a plurality of compartments arranged between spokes extending between said elevate rib and said rim, the spokes having flat upper surfaces defining said leveling plane.

5. The container of claim 4, wherein said lid further comprising:
a central well defined in a middle region of said lid and having a shoulder matching the contour of said elevate rib to seal said central chamber and prevent items in said central chamber to contact items in said compartments.

6. The container of claim 1, wherein said mixing tray has a channelled bottom and holding means provided at least on one side of the tray.

7. A container arrangement for storing related items, comprising:
a primary container having a circumferential edge with an inverted-U
shape;
a tray having a plurality of compartments and a central chamber defined around a partition wall in a middle region of the tray, said partition wall connected to said outer wall through an elevate rib extending slightly above a levelling plane; and a lid having a central well defined in a middle region of said lid, said central well having a shoulder cooperating with an upper side of said elevate rib for sealing said central chamber and preventing items in said central chamber to contact items in said compartments in a store-transport state.

8. The container of claim 7, wherein said tray further comprising, a flange extending outwardly in a leveling plane substantially perpendicular to said outer wall, said outer wall sized to be tightly nested in said cavity when said tray is arranged in said open top in a concave position in said store-transport state; and a rim integrally formed with said outer wall, said rim projecting outwardly and contiguous with said flange and being sized to snap fit in said open top when said tray is inverted and arranged in a convex position in a mixing state.

9. The container of claim 8, wherein said lid having a peripheral ledge for compressing said flange against said circumferential edge providing an airtight sealed container arrangement in said store-transport state and preventing contact between items arranged in different layers.

10. The container of claim 8, wherein said plurality of compartments are arranged between spokes extending between said elevate rib and said rim, the spokes having flat upper surfaces defining said leveling plane.

11. The container of claim 7, wherein said mixing tray has a channelled bottom and holding means provided on at least one side of the tray.

12. A container arrangement for storing and mixing related items, comprising:
a primary container having a container body with upright walls, an open top, and an interior surface defining a cavity, said open top having a circumferential edge with an inverted-U shape;
a tray with a plurality of compartments and holding means provided at least on one side of the tray;
a lid having a peripheral ledge, said peripheral ledge cooperating with said circumferential edge to provide an airtight sealed container arrangement containing said tray disposed in a concave position and prevent contact between items arranged in different layers and compartments in a store-transport state, said holding means for inverting said tray to assume a convex position on said open top and provide a leakproof container arrangement in a mixing state.

13. The container of claim 12, wherein said tray having an un-tapered outer wall and a flange extending outwardly in a leveling plane substantially perpendicular to said outer wall, the outer wall sized to be tightly nested in said cavity when said tray is arranged on said open top in said concave position.

14. The container of claim 13, wherein said outer wall having a rim projecting outwardly and contiguous with said flange, said rim being sized to snap fit in said open top when said tray is inverted and arranged in said convex position in said mixing state.

15. The container of claim 13, wherein said peripheral ledge comprising a channel, a collar, and a sleeve, said circumferential edge comprising a lip and a skirt, said rim engaging said channel, said collar and said sleeve cooperating with said lip and said skirt, respectively, for firmly holding said flange in-between and sealing the container in said store-transport state.

16. The container of claim 12, wherein said mixing tray further comprising:
a central chamber defined around a partition wall in a middle region of the tray, said partition wall connected to said outer wall through an elevate rib extending slightly above a leveling plane; and a plurality of compartments defined by spokes extending between said elevate rib and said rim, the spokes having flat upper surfaces defining said leveling plane.

17. The container of claim 16, wherein said lid further comprising:
a central well defined in a middle region of said lid and having a shoulder matching the contour of said elevate rib to seal said central chamber and prevent items in said central chamber to contact items in said compartments.