NL2034754B1

NL2034754B1 - Petri dish storage

Info

Publication number: NL2034754B1
Application number: NL2034754A
Authority: NL
Inventors: Johan Meinderts Jorn; Van Kins Sjoerd; Paul Christiaan Van Schaik Jan
Original assignee: Viscon Group Holding B V
Priority date: 2023-05-03
Filing date: 2023-05-03
Publication date: 2024-11-14

Abstract

The present invention relates to a Petri dish storage assembly that comprises a plurality of Petri dish units and a Petri dish cartridge. The present invention further relates to said Petri dish cartridge, to a system for unloading the Petri dish cartridge, and to a system for loading the Petri dish cartridge. According to the present invention, the Petri dish storage assembly comprises a plurality of Petri dish units, and a Petri dish cartridge configured to hold the plurality of Petri dish units arranged in a stack. The Petri dish cartridge comprises a tubular member having a first opening and a second opening arranged at a first end and an opposite second end of the tubular member, a first sealing member configured to be removably coupled to the first end of the tubular member for sealing the first opening, a second sealing member configured to be removably coupled to the second end of the tubular member for sealing the second opening, and a movement limiter arranged inside the tubular member and configured for allowing Petri dish units to be arranged in the tubular member through the first opening while preventing Petri dish units from leaving the tubular member through the first opening.

Description

PETRI DISH STORAGE

The present invention relates to a Petri dish storage assembly that comprises a plurality of

Petri dish units and a Petri dish cartridge. The present invention further relates to said Petri dish cartridge, to a system for unloading the Petri dish cartridge, and to a system for loading the Petri dish cartridge.

Petri dishes are known in the art. A Petri dish is a shallow transparent dish with a lid that for example biologists use to hold growth medium in which cells can be cultured. For example, cells of bacteria, fungi, or plant material can be grown or cultured in a Petri dish. Within the context of the present invention, the combination of the Petri dish with the lid is referred to as a

Petri dish unit.

In contemporary biological research and/or production facilities, many steps are automated. For example, dispensing or aspiration of liquids into or from Petri dishes can be performed using robotic arms that are provided with suitable nozzles. These steps can only be performed after removing the lid from the Petri dish. At the same time, it is preferred to keep the lid on the Petri dish as long as possible to avoid any contamination or other disturbance of the culturing process inside the Petri dish.

Automation of steps improves the throughput of a given system. Accordingly, a problem arises in contemporary systems in that the steps required for selecting a Petri dish unit among a plurality of Petri dish units for processing becomes a limiting factor. For example, selecting a Petri dish unit among a plurality of Petri dish units is performed manually. In general, in contemporary systems, the process of carrying and handling multiple Petri dishes is quite cumbersome, thereby limiting the throughput of the system.

It is an object of the present invention to provide a Petri dish storage assembly in which these problems are at least partially resolved.

According to a first aspect of the present invention, a Petri dish storage assembly is provided as defined in appended claim 1. It comprises a plurality of Petri dish units, and a Petri dish cartridge configured to hold the plurality of Petri dish units arranged in a stack. The Petri dish cartridge comprises a tubular member having a first opening and a second opening arranged at a first end and an opposite second end of the tubular member, respectively, wherein the first and second openings are each configured for allowing a Petri dish unit to be arranged into and/or extracted from the tubular member along a longitudinal axis of the tubular member.

The Petri dish cartridge further comprises a first sealing member configured to be removably coupled to the first end of the tubular member for sealing the first opening, and a second sealing member configured to be removably coupled to the second end of the tubular member for sealing the second opening. The cartridge further comprises a movement limiter arranged inside the tubular member and configured for allowing Petri dish units to be arranged in the tubular member through the first opening while preventing Petri dish units from leaving the tubular member through the first opening.

Using the movement limiter, Petri dishes can be stacked by inserting them through the first opening. When the tubular member is filled completely, the first and second openings can be sealed using the first and second sealing members, respectively.

The Petri dish cartridge with the plurality of Petri dishes arranged as a stack inside the tubular member can be used for automatic handling. For example, after having removed the first and second sealing members, the Petri dish unit closest to the first opening can be pushed. This will result in the Petri dish closest to the second opening to be pushed out of the tubular member.

This process can be repeated until all Petri dish units are removed from the tubular member. The steps of pushing the Petri dish units through the first opening and collecting ejected Petri dish units at the second opening can be automated.

An inner dimension of the tubular member may correspond to a maximum outer dimension of the Petri dish units. For example, the inner dimension of the tubular member may be substantially identical to or slightly larger than the maximum outer dimension of the Petri dish units. This allows a close fit between the Petri dish units and the tubular member such that little to no relative movement between the tubular member and the Petri dish units is generated when transporting the Petri dish cartridge holding the Petri dish units. To this end, the Petri dish units preferably have an identical shape and size.

In some embodiments, the movement limiter extends inside the tubular member when it allows a Petri dish unit to pass through the first opening. In such embodiments, the inner dimension of the tubular member may be slightly larger than the maximum outer dimension of the Petri dish units. For example, the inner dimension of the tubular member could be 90 mm, whereas the maximum outer dimension of the Petri dish units could equal 96 mm. The movement limiter can be accommodated in the space between the Petri dish units and a wall of the tubular member.

In other embodiments, the movement limiter extends fully inside a wall of the tubular member when it allows a Petri dish unit to pass through the first opening. In such embodiments, the inner dimension of the tubular member may be substantially equal to the maximum outer dimension of the Petri dish units. For example, the movement limiter may comprise a latch that is slidably received in the wall of the tubular member. This latch may be spring biased and may be provided with a slanted or chamfered side that faces the first opening. When Petri dish units are pushed into the tubular member through the first opening, they will engage the latch and push the latch against the spring bias force into the wall of the tubular member. When the Petri dish units have moved past the latch, the latch will regain its original position due to the spring bias force. As the opposing side of the latch is not slanted or chamfered, Petri dish units exerting a force onto the latch from this side will not cause the latch to move inward.

The tubular member may comprise a hollow cylinder of which an inner radius corresponds to a maximum outer dimension of the Petri dish units. For example, the inner radius of the hollow cylinder may be substantially identical to or slightly larger than the maximum outer dimension of the Petri dish units. Other cross-sectional shapes of the tubular member, and/or shapes of the Petri dish units are not excluded. However, to prevent the abovementioned relative movement, the Petri dish units and tubular member should have complementary shapes at least in a plane perpendicular to the longitudinal axis of the tubular member.

Multiple tubular members may be provided in a single housing. In such a system, the unit configured for arranging the Petri dish units inside a respective tubular member and for pushing onto the Petri dish units for ejecting a Petri dish unit through the second opening of a respective tubular member, and the unit for collecting an ejected Petri dish unit at the second opening of a respective tubular member may have a fixed position, for example relative to a supporting frame.

In this system, the housing and the tubular members arranged therein are rotated to bring a respective tubular member into alignment with the abovementioned units. In this embodiment, the tubular members resemble the chambers of a revolver. However, the present invention is not limited to such embodiment. Alternative arrangements such as an inline buffer or hotel storage could be used.

The first and/or second sealing member may comprise a base and a rim extending from the base, wherein the rim is provided on an inside thereof with a primary coupling member, and wherein the tubular member is provided, near the first and second ends, with a secondary coupling member that is configured to be coupled with the primary coupling member. In addition, the Petri dish storage assembly may further comprise, for the first and/or second sealing member, a first sealing ring connected to the base or to an edge of the tubular member, wherein the first sealing ring is configured to provide a sealing between the first end or second end of the tubular member and the base when the first or second sealing member is coupled to the tubular member, respectively. The first sealing ring may be connected and/or fitted to the base of the respective sealing member or to the edge of the tubular member. For example, a base of the first and/or second sealing member, or the edge of the tubular member, can be provided with a recess in which the first sealing ring is partially received.

The primary and secondary coupling members may comprise mutually corresponding threading.

The tubular member may comprise a tubular body and, for the purpose of coupling with the first and/or second sealing member, a sleeve having an inner surface with which itis or is configured to be arranged around the tubular body near the first and second opening, respectively,

and wherein the secondary coupling member is formed and/or provided on an outer surface of the sleeve. The assembly may further comprise a second sealing ring arranged in between the tubular body and the sleeve. The second sealing ring may be connected and/or fitted to the sleeve, or to the tubular body. For example, the sleeve can be provided on its inner surface or the tubular body on its outer surface with a recess in which the second sealing ring is arranged. Furthermore, the sleeve can be removably mounted around the tubular body. As an example, the sleeve is made from at least partially resilient material.

The movement limiter may comprise a resilient protruding member extending inward from an inner wall of the tubular member in a direction away from the first opening. The resilient protruding member can be configured to be bent towards the inner wall by a Petri dish unit when arranging this Petri dish unit in the tubular member through the first opening, and to block a Petri dish unit from leaving the tubular member through the first opening. Alternatively, the movement limiter may comprise a protruding member that is hingedly coupled to and inward extending from an inner wall of the tubular member in a direction away from the first opening. In this case, the protruding member can be configured to pivot or hinge towards the inner wall by a Petri dish unit when arranging this Petri dish unit in the tubular member through the first opening, and to block a

Petri dish unit from leaving the tubular member through the first opening. In both cases, Petri dish units are able to pass through the first opening in one direction only, namely from outside to inside of the tubular member. In both cases, a plurality of said protruding members can be provided, wherein the protruding members are arranged spaced apart.

The movement limiter may comprise a resilient ring or sheet that is arranged inside the tubular member. For example, an outer edge of the ring or sheet may be fixedly positioned in and/or fastened to the tubular member. The resilient ring or sheet may have an inner opening of which a size is smaller than the Petri dish units. The resilient ring can be configured to deform when Petri dish units are pushed through the inner opening with sufficient force, while preventing deformation as a result of the Petri dish units inside the tubular member resting on the resilient ring or sheet that would allow the Petri dish units to leave the tubular member.

A distance between the first and second sealing members, when arranged on the tubular member, may correspond to an integer times a height of a single Petri dish unit. For example, the distance between the first and second sealing members may correspond to n times the height of a

Petri dish unit, wherein n is a non-zero integer. This allows a stack of n Petri dish units to be arranged in the tubular member while preventing or limiting movement of the Petri dish units during transport of the cartridge.

Alternatively, the first and second sealing members can be at least partially resilient along the longitudinal axis of the tubular member. In this case, a distance between the first and second sealing members when arranged on the tubular member and with no Petri dish units arranged in the tubular member can be slightly smaller than an integer times a height of a single Petri dish unit.

This allows the plurality of Petri dish units to be clamped in between the first and second sealing members.

The plurality of Petri dish units can be arranged as a stack of Petri dish units in the tubular 5 member. Alternatively, the plurality of Petri dish units is arranged outside of the Petri dish cartridge.

According to a second aspect, the present invention provides a Petri dish cartridge configured as the Petri dish cartridge of the Petri dish storage assembly described above.

According to a third aspect, the present invention provides a system for unloading a filled

Petri dish cartridge of the abovementioned Petri dish storage assembly. This system comprises a holder for holding the Petri dish cartridge. The system further comprises an engaging member, and a drive unit for bringing the engaging member into the tubular member of the Petri dish cartridge through the first opening of the tubular member to thereby push on a first end of the stack of the

Petri dish units such that a Petri dish unit on a second end of the stack of Petri dish units is moved through the second opening out of the Petri dish cartridge. The system further comprises a collecting unit for collecting the Petri dish unit that has moved through the second opening from the Petri dish cartridge.

According to a fourth aspect, the present invention provides a system for loading an empty

Petri dish cartridge with a plurality of Petri dish units using the abovementioned Petri dish storage assembly. This system comprises a holder for holding the Petri dish cartridge, an engaging member, and a drive unit for bringing the engaging member into the tubular member of the Petri dish cartridge through the first opening to thereby push a Petri dish unit that has been arranged in between the first opening and the engaging member into the Petri dish cartridge. Preferably, the drive unit is configured to move an end of the engaging member that is configured to engage the

Petri dish unit beyond the protruding member.

In the abovementioned systems for unloading and loading a Petri dish cartridge, the engaging member may comprise a piston rod, and the drive unit can be configured for performing a retracting or extracting movement of the piston rod, wherein an end of the piston rod is configured to engage a Petri dish unit for the purpose of loading or unloading the Petri dish cartridge. The drive unit and engaging member can for example be formed using a pneumatic, electric, or hydraulic cylinder.

Next, the present invention will be described in more detail referring to the appended drawings, wherein identical or similar components are referred to using the same reference signs, and wherein:

Figure 1 illustrates an embodiment of a Petri dish cartridge in exploded view according to the present invention;

Figure 2 illustrates a cross-sectional view of the Petri dish cartridge of figure 1;

Figures 3A and 3B illustrate detailed cross-sectional views of the second sealing member and first sealing member, respectively, of the Petri dish cartridge of figure 1;

Figure 4 illustrates a system for unloading a Petri dish cartridge in accordance with the present invention; and

Figure 5 illustrates a system for loading a Petri dish cartridge in accordance with the present invention.

An exploded view of an embodiment of a Petri dish cartridge 10 is shown in figure 1. It comprises a tubular member 1. which has a tubular body 1A that is for example made of

Polycarbonate or another thermoplastic material. Tubular member 1 has a first end El and a second end E2. At first end E1, tubular member 1 has a first opening and at second end E2, tubular member 1 has a second opening.

Petri dish cartridge 10 is configured for holding a plurality of Petri dish units 9 that each comprise a Petri dish 91 and a lid 92. The dimensions and shape of Petri dish units 9 in a plane perpendicular to the longitudinal axis of tubular body 1A match the inner dimensions and shape of tubular body 1A in that plane, respectively. As an example, lid 92 may have a circular shape with an outer diameter of 90 mm. In this case, tubular body 1A has a cylindrical shape with an inner diameter of 96 mm. It should be noted that other complementary shapes and dimensions are possible for tubular body 1A and Petri dish units 9.

The first and second openings can be closed using a first sealing member 3A and second sealing member 3B, respectively, wherein sealing members 3A, 3B could be identical. This is shown in more detail in figure 2 and figures 3A and 3B.

First and second sealing members 3A, 3B each comprise a base 31 from which a rim 32 extends. On an inner surface of rim 32, a threading 35 is provided.

As shown in figure 1 and figure 2, near first end E1 and second end E2, respective sleeves 2A, 2B are provided which are provided with a threading 4 arranged on their outer sides. As shown in figures 3A and 3B, sleeves 2A, 2B are provided on their inner surfaces with a recess in which a sealing ring 6B is provided. When sleeves 2A, 2B are arranged around tubular body 1A, sealing rings 6B provide a sealing between sleeves 2A, 2B and tubular body 1A. Alternatively, the recess is provided in tubular body 1A instead of sleeves 2A, 2B.

First and second sealing members 3A, 3B can be coupled to tubular member 1. To this end, a user grabs a gripping member 33 formed in base 31 of sealing member 3A, 3B and rotates sealing member 3A, 3B relative to tubular member 1. This will cause threading 35 and threading 4 to become coupled.

Base 31 of sealing members 3A, 3B is provided with a recess in which a sealing ring 6A is provided. When sealing members 3A, 3B are properly fastened, sealing ring 6A will be pressed against an upper edge of sleeve 2A, 2B or tubular body 1A. Sealing ring 6A ensures that no to little air leakage is possible between the inside of tubular member 1 and the outside through clearances between sealing member 3A, 3B and tubular body 1A and/or sleeve 2A, 2B, respectively. As discussed above, air leakage between sleeve 2A, 2B and tubular body 1A is prevented using sealing ring 6B. Hence, together, sealing rings 6A, 6B provide an airtight sealing of tubular member 1. Alternatively, the recess for sealing ring 6A can be provided in the upper edge of sleeve 2A, 2B or tubular body 1A.

Bases 31 comprise an inward protruding part 34. In this latter part, gripping member 33 is defined. As shown in figure 2, inward protruding parts 34 of first and second sealing members 3A, 3B mutually define a length L along the longitudinal axis of tubular member 1 along which Petri dish units 9 can be arranged in tubular member 1. Inward protruding parts 34 are configured for clamping or confining Petri dish units 9 along the longitudinal axis.

Cartridge 10 is particularly well suited for accommodating a plurality of identical Petri dish units 9. A Petri dish unit 9 may have a height hl. Length L may in this case substantially correspond to an integral times height hl. When sealing members 3A, 3B are at least partially resilient along the longitudinal axis of tubular member | when they are arranged on tubular member 1, the stack of Petri dish units 9 may have a height hl that is slightly larger than length L measured when no Petri dish units 9 are arranged inside tubular member 1. To accommodate Petri dish units 9, sealing members 3A, 3B will deform allowing Petri dish units 9 to be clamped in between sealing members 3A, 3B.

As shown in figure 2, cartridge 10 may comprise an optional handle § allowing a user to carry cartridge 10.

Figure | further depicts movement limiter 7 that is arranged inside tubular member 1 as shown in figure 2 and figure 3B. Movement limiter 7 comprises a ring-shaped base 71 from which aplurality of resilient elements 72 protrude in a direction away from the first opening and away from an inner wall of tubular body 1A.

When a Petri dish unit 9 is inserted through the first opening, elements 72 are pushed towards the inner wall of tubular body 1A allowing Petri dish unit 9 to be arranged inside tubular member 1. However, elements 72 prevent Petri dish units 9 to move in the opposite direction, i.e. from inside tubular member 1 through the first opening to outside tubular member 1.

Figure 4 illustrates system 100 for unloading Petri dish cartridge 10. It comprises a holder 110 for Petri dish holding cartridge 10. It further comprises a pneumatic, electric, or hydraulic cylinder 130 from which a piston rod 131 extends. Piston rod 131 is able to make a back-and-forth movement along the longitudinal axis of tubular member 1.

By causing piston rod 131 to move into tubular member 1, a lowest Petri dish unit 9A of the stack of Petri dish units 9 inside Petri dish cartridge 10 can be engaged. This causes an upper

Petri dish unit 9B of the stack of Petri dish units 9 to be pushed out of cartridge 10. A further pneumatic, electric, or hydraulic cylinder 120 with piston rod 121 can be used for manipulating

Petri dish unit 9B. For example, Petri dish unit 9B can be collected to start a sequence of steps to be performed on the contents of Petri dish unit 9B. It should be noted that the present invention is not limited to cylinder 120 and piston rod 121. Instead, other units for collecting the Petri dish units that have moved through the second opening from cartridge 10 can be used. Similarly, the present invention is not limited to cylinder 130 and piston rod 131. Instead, other engaging members and drive units can be used for engaging Petri dish units inside tubular member 10.

Figure 5 illustrates the process of arranging Petri dish unit 9A inside Petri dish cartridge 10. In the left figure, Petri dish unit 9A is arranged in between piston rod 131 and the first opening of tubular member 1 of cartridge 10. By moving piston rod 131 upward, Petri dish unit 9A is pushed into tubular member 1. There it will push resilient members 72 to the side, allowing it to move further into tubular member 1. More in particular, piston rod 131 moves into tubular member 1 such that a bottom surface of Petri dish unit 9A is pushed beyond resilient members 72 allowing the latter to move back to their original position. In this position, resilient members 72 will prevent

Petri dish unit 9A from falling out of Petri dish cartridge 10 when held in the upright position as shown in figure 5.

Figure 5 illustrates loading of Petri dish cartridge 10 through the first opening of tubular member 1. However, the present invention is not limited thereto. Another possibility for loading cartridge 10 comprises moving piston rod 131 through the first opening inside tubular member to a position near the second opening. There, a Petri dish unit 9 can be inserted into tubular member 1 via the second opening. Once inside tubular member 1, Petri dish unit 9 is supported by piston rod 131. Lowering the latter allows for a next Petri dish unit 9 to be placed inside tubular member 1.

This process can be repeated until the first placed Petri dish unit 9 no longer requires support from piston rod 131 but is supported by resilient members 72. Once completely filled, cartridge 10 can be closed using first sealing member 3A and second sealing member 3B.

It should be noted that the present invention is not limited to resilient members 72 as movement limiter. Rather, the movement limiter may comprise a protruding member that is hingedly coupled to and inward extending from an inner wall of the tubular body 1A in a direction away from the first opening. In this case, the protruding member can be configured to pivot or hinge towards the inner wall by a Petri dish unit when arranging this Petri dish unit inside the tubular member through the first opening, and to block a Petri dish unit from leaving the tubular member through the first opening. In this case, the protruding member need not be resilient.

In the above, the present invention has been explained using detailed embodiments thereof.

However, the present invention is not limited to these embodiments. Instead, various modifications are possible without deviating from the scope of the present invention, which is defined by the appended claims and their equivalents.

Claims

CONCLUSIONS

1. A Petri dish storage assembly comprising: a plurality of Petri dish units (9, 9A, 9B), each Petri dish unit comprising a Petri dish (91) and an associated lid (92); a Petri dish cassette (10) adapted to store the plurality of Petri dish units arranged in a stack, the Petri dish cassette comprising: a tubular member (1} having a first opening and a second opening arranged at a first end (E1) and an opposite second end (E2) of the tubular member, respectively, the first and second openings each being adapted to facilitate a Petri dish unit being arranged in or removed from the tubular member along a longitudinal axis of the tubular member; a first sealing member (3A) adapted to be removably coupled to the first end of the tubular member for sealing the first opening; a second sealing member (3B) adapted to be removably coupled to the second end of the tubular member for sealing the second opening; and a movement limiter (7) arranged within the tubular member and adapted to allow Petri dish units to be inserted into the tubular member arranged through the first opening, while preventing Petri dish units from exiting the tubular portion through the first opening.

2. A Petri dish storage assembly according to claim 1, wherein an internal dimension of the tubular part corresponds to a maximum external dimension of the Petri dish units.

3. A Petri dish storage assembly according to claim 2, wherein the tubular part comprises a hollow cylinder having an internal radius corresponding to a maximum external dimension of the Petri dish units.

4. Petri dish storage assembly according to any of the preceding claims, wherein the first and/or second sealing part comprises: a base (31) and a rim (32) extending from the base, the rim being provided on an inner side thereof with a primary coupling part (35), and the tubular part being provided near the first end and the second end with a secondary coupling part (4) adapted to be coupled to the primary coupling part.

5. A Petri dish storage assembly according to claim 4, further comprising, for the first and/or second sealing member, a first sealing ring (6A) connected to the base or to an edge of the tubular member, the first sealing ring being adapted to provide a seal between the first end or the second end of the tubular member and the base when the first or second sealing member is coupled to the tubular member, respectively.

6. Petri dish storage assembly according to claim 5, wherein a base of the first sealing part and/or the second sealing part, or the edge of the tubular part, is provided with a recess in which the first sealing ring is partially received.

7. Petri dish storage assembly according to claim 5 or 6, wherein the primary and secondary coupling parts comprise mutually corresponding threads.

8. Petri dish storage assembly according to any one of claims 4 to 7, wherein the tubular part comprises a tubular body (1A) and, for coupling to the first sealing part and/or the second sealing part, a sleeve (2A, 2B) having an inner surface with which it is or is adapted to be arranged around the tubular body adjacent to the first opening and second opening, respectively, and wherein the secondary coupling part is formed and/or arranged on an outer surface of the sleeve.

9. A Petri dish storage assembly according to claim 8, further comprising a second sealing ring (6B) arranged between the tubular body and the sleeve.

10. Petri dish storage assembly according to claim 9, wherein the sleeve on its inner surface or the tubular body on its outer surface is provided with a recess in which the second sealing ring is arranged.

11. Petri dish storage assembly according to any one of claims 8 to 10, wherein the sleeve is removably mounted around the tubular body.

A Petri dish storage assembly according to any preceding claim, wherein the movement restrictor comprises a resilient projection (72) extending inwardly from an inner wall of the tubular member in a direction away from the first opening, the resilient projection being adapted to be deflected toward the inner wall by a Petri dish unit when said Petri dish unit is disposed in the tubular member through the first opening, and to prevent a Petri dish unit from exiting the tubular member through the first opening.

13. A Petri dish storage assembly as claimed in any one of claims 1 to 11, wherein the movement restrictor comprises a projection pivotally coupled to and extending inwardly from an inner wall of the tubular member in a direction away from the first opening, the projection being adapted to pivot or pivot toward the inner wall through a Petri dish unit when such Petri dish unit is disposed within the tubular member through the first opening, and to prevent a Petri dish unit from exiting the tubular member through the first opening.

14. A Petri dish storage assembly according to claim 12 or 13, comprising a plurality of said protruding parts, wherein] the protruding parts are arranged at a distance from each other.

15. A Petri dish storage assembly according to any preceding claim, wherein the movement restrictor comprises a resilient ring or plate arranged within the tubular portion, the resilient ring or plate having an inner opening having a dimension smaller than the Petri dish units; the resilient ring being adapted to deform when the Petri dish units are pushed through the inner opening with sufficient force, while preventing deformation due to the Petri dish units resting in the tubular portion on the resilient ring or plate, which deformation would allow the Petri dish units to leave the tubular portion.

16. A Petri dish storage assembly according to any preceding claim, wherein a distance between the first and second sealing members, when arranged on the tubular member, corresponds to an integer number of times the height of a single Petri dish unit.

17. A Petri dish storage assembly according to any preceding claim, wherein the first and second sealing members are at least partially resilient along the longitudinal axis of the tubular member, and wherein a distance between the first and second sealing members when arranged on the tubular member and without Petri dish units arranged in the tubular member is slightly less than an integer times the height of a single Petri dish unit, thereby allowing the plurality of Petri dish units to be clamped between the first and second sealing members.

18. A Petri dish storage assembly according to any preceding claim, wherein the plurality of Petri dish units are arranged as a stack of Petri dish units in the tubular portion.

19. A Petri dish storage assembly according to any preceding claim, wherein the plurality of Petri dish units are arranged outside the Petri dish cassette.

20. Petri dish cassette (10) configured as the Petri dish cassette of the Petri dish storage assembly as defined in any of claims 1 to 19.

A system (100) for unloading the Petri dish cassette (10) from the Petri dish storage assembly according to claim 18, comprising: a holder (110) for holding the Petri dish cassette; an engagement member (131); a drive unit (130) for inserting the engagement member into the tubular portion of the Petri dish cassette of the Petri dish storage assembly through the first opening of the tubular portion to thereby push on a first end of the stack of the Petri dish units such that a Petri dish unit (9B) at a second end of the stack of Petri dish units is moved out of the Petri dish cassette through the second opening; a collecting unit (120) for collecting the Petri dish unit moved through the second opening of the Petri dish cassette.

22. A system (200) for loading the Petri dish cassette (10) of the Petri dish storage assembly according to claim 19, comprising: a holder (110) for holding the Petri dish cassette; an engagement member (131); a drive unit (130) for inserting the engagement member into the tubular portion of the Petri dish cassette through the first opening to thereby

Petri dish unit (9A) of the plurality of Petri dish units disposed between the first opening and the engagement member to be pushed into the Petri dish cassette.

23. The system of claim 22, wherein the drive unit is adapted to move the end of the engagement member adapted to engage the Petri dish unit past the protruding portion.

24. System according to any of claims 21 to 23, wherein the engagement member comprises a piston rod, the drive unit being adapted to perform a retracting or extending movement of the piston rod.