CN120393834B

CN120393834B - A flow cytometry antibody premixing device

Info

Publication number: CN120393834B
Application number: CN202510898877.5A
Authority: CN
Inventors: 汪玲; 吴竹君; 芮火飞; 李慧明
Original assignee: First Affiliated Hospital of Nanchang University
Current assignee: First Affiliated Hospital of Nanchang University
Priority date: 2025-07-01
Filing date: 2025-07-01
Publication date: 2025-09-05
Anticipated expiration: 2045-07-01
Also published as: CN120393834A

Abstract

The present invention relates to the field of cell detection technology, and in particular to a flow cytometry antibody premixing device. It comprises a box body with a chamber, an elastic movable part extending into the chamber and connecting with the box body, and two notches and gaps are provided on the side wall of the elastic movable part to form two movable flaps. When there is no external force squeezing, the two movable flaps tend to extend and fit toward the notches and gaps to form a closed space in the chamber below the movable flaps; an annular body is installed on the inner wall of the elastic movable part, and when there is external force squeezing, the annular body is deformed to form a closed space in the chamber below the annular body; an EP tube is installed in the chamber for premixing flow cytometry antibodies. The present invention can ensure that the EP tube in the box body is always in a closed state isolated from the outside world during the process of configuring the antibody mixture, thereby reducing contact with the outside world and reducing the risk of contamination of the antibody mixture.

Description

Flow cell antibody premixing device

Technical Field

The invention relates to the technical field of cell detection, in particular to a flow type cell antibody premixing device.

Background

The flow cytometry is a single-cell quantitative analysis and separation technology by utilizing a flow cytometry, can carry out multi-parameter high-speed analysis and separation on small particle substances such as cells, microorganisms and the like, has the characteristics of quantification, flexibility, rapidness and the like, and is one of the cell quantitative analysis technologies at the forefront of the current stage.

Some specific reagents are very important for flow cytometry techniques, such as fluorochrome-labeled antibodies against specific cellular antigens. The inspector will end up determining the best available antibodies, luciferin and combinations thereof by optimizing each regimen to increase accuracy and reduce errors and variances. Antibody mixtures are a very useful tool in clinical protocols laboratories, helping to detect consistency. The antibody mixture is prepared by combining the single antibodies for analysis into a tube, and has the advantages of low cost, flexible customization and the like compared with the direct purchase of the antibody mixture prepared by a detector, and each monoclonal antibody must be titrated separately to realize the optimal signal-to-noise ratio separation when the antibody mixture is prepared.

When more antibodies need to be mixed in preparing the antibody mixture, the EP tube for preparing the antibody mixture is kept in a continuously open state, and the continuously open state of the EP tube increases the risk of contamination of the antibody mixture when a tester performs a preparation operation.

Disclosure of Invention

The present invention aims to at least ameliorate one of the technical problems of the prior art. To this end, the invention proposes a flow cell antibody premixing device.

The technical scheme of the invention is as follows:

A flow cell antibody premixing device, comprising:

the box body is provided with a cavity, and a through hole is formed in the surface of the box body;

The elastic movable piece penetrates through the through hole and extends into the cavity, the elastic movable piece is connected with the surface of the box body, the pipe diameter of the elastic movable piece, which is far away from the surface of the box body, is gradually contracted and is used for the pipette to penetrate through and extend into the cavity, two gap gaps are formed in the side wall of the elastic movable piece to form two movable petals, and when the elastic movable piece is extruded without external force, the two movable petals tend to extend and fit with the gap gaps to enable the cavity below the movable petals to form a closed space;

The annular body is arranged on the inner wall of the elastic movable piece and is positioned above the movable valve, and when the annular body is extruded by external force, the annular body deforms so that a cavity below the annular body forms a closed space;

and an EP tube installed in the chamber for premixing the flow cell antibodies.

In one possible solution, further, the annular body includes:

The limiting strips are distributed in an annular interval mode, and a gap is reserved between every two adjacent limiting strips;

And each sealing belt penetrates through the gap to be respectively connected with two adjacent limiting strips to form an annular closed loop, and the sealing belts are used for deforming the annular body when the sealing belts are extruded by external force so as to enable the cavity below the annular body to form a closed space.

In one possible technical solution, further, the sealing belt has an arc profile deviated from the limit bar, and when the sealing belt is extruded by an external force, the sealing belt stretches near the direction of the limit bar so as to increase the area of the area surrounded by the annular body, and a displacement space is provided for the pipette.

In one possible solution, further, the annular body further includes:

one end of the clamping piece is connected with the side wall of the limit strip deviating from the elastic movable piece.

In one possible technical solution, further, the sealing strip has a first side arc and a second side arc, wherein the first side arc is an inner side arc close to the surface of the limit strip, the second side arc is an outer side arc deviated from the surface of the limit strip, and the arc length of the first side arc is greater than the arc length of the second side arc.

In a possible technical scheme, further, keep away from spacing the fastener tip approaches elasticity moving part inner wall sets up, the fastener encloses into the screens clearance with spacing upper surface and elasticity moving part inner wall for the closing belt passes, the holistic seal of hoisting device, wherein the fastener is used for increasing the spacing effect of screens clearance.

In one possible technical solution, further, the sealing strip is made of an elastic material, so as to facilitate the compression and expansion to seal the gap.

In a possible technical scheme, further, two movable petals are symmetrically distributed, so that the movable petals can be uniformly supported outwards when being pressed conveniently to ensure that the pipette is vertically moved downwards, and the situation that the pipette touches the movable petals due to deformation asymmetry is avoided.

In a possible solution, further, a groove is provided on the inner side of the tank for fixing the EP tube.

In one possible technical scheme, further, any side face of the box body is provided with visual glass, so that the box body is convenient to observe.

According to the flow type cell antibody premixing device, the EP pipe provided with the antibody mixture in the box body can be ensured to be in a closed state isolated from the outside in the whole process before and after the antibody is prepared, so that the contact with the outside is reduced, and the pollution risk of the antibody mixture is reduced. The concrete steps are as follows:

At least two movable petals are formed by arranging at least two notches at the middle lower end of the elastic movable part, a supporting force is generated between the surface of the liquid-transferring gun barrel nozzle ejector and the inner wall of the limit strip in the process of entering the elastic movable part, the movable petals are outwards spread, the nozzle ejector and the disposable nozzle cone conveniently enter a cavity of the box body, and the limit effect of the clamping part on the sealing strip ensures that the sealing strip maintains a tight sealing fan ring gap state in the process of penetrating the fan ring gap between the limit strips so as to isolate external contact;

In the process of opening the lower end of the movable valve, the lower end of the cavity of the elastic movable part enclosed by the movable valve is communicated with the cavity of the box body, so that the whole formed by at least two limiting strips is a complete annular body under the penetration of the sealing strip, the whole is conveniently separated from the upper end of the cavity of the elastic movable part, the tightness of the whole pipetting gun in the process of entering the device is ensured when antibodies are mixed, and the risk of antibody mixture pollution caused by continuous opening of an EP tube is reduced.

Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are needed in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and that other drawings can be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 is an overall schematic of a flow cell antibody premixing device in accordance with an embodiment of the present invention;

FIG. 2 is a schematic view showing the opening and closing of a door of a flow cell antibody premixing device according to an embodiment of the present invention;

FIG. 3 is a schematic view of the structure of an elastic movable member of a flow cell antibody premixing device according to an embodiment of the present invention;

FIG. 4 is a schematic view of another view of the elastic movable member of the flow cell antibody premixing device according to an embodiment of the present invention;

FIG. 5 is a schematic diagram of the annular body structure of a flow cell antibody premixing device in accordance with an embodiment of the present invention;

FIG. 6 is a cross-sectional view of a flow cell antibody premixing device prior to deformation in accordance with an embodiment of the present invention;

FIG. 7 is a partial enlarged view of a flow cell antibody premixing device prior to deformation in accordance with an embodiment of the present invention;

FIG. 8 is a deformed internal cross-sectional view of a flow cell antibody premixing device in accordance with an embodiment of the present invention;

FIG. 9 is an enlarged partial cross-sectional view of a deformed flow cell antibody premixing device in accordance with an embodiment of the present invention;

FIG. 10 is a schematic illustration of deformation of the annulus of a flow cell antibody premixing device before and after compression in accordance with an embodiment of the present invention;

FIG. 11 is a plan view of the lower and upper ends of a stop bar of a flow cell antibody premixing device according to an embodiment of the present invention;

FIG. 12 is a comparison of the overall detail deformation of the stop bars and gaps of a flow cell antibody premixing device in accordance with an embodiment of the present invention;

FIG. 13 is an overall detail view of the stop bars and the detent gaps of a flow cytometric antibody premixing device according to an embodiment of the present invention.

Reference numerals:

The box body 1, the chamber 101, the groove 102, the visible glass 103 and the switch door 104;

An elastic movable piece 2, a gap 201 and a movable flap 202;

a pipette 3, a nozzle ejector 31, and a disposable nozzle cone 32;

a ring-shaped body 4;

EP tube 5:

The limit bar 41, the gap 410, the closing band 42, the clamping piece 43 and the clamping gap 430.

Detailed Description

The following detailed description of embodiments of the application, with reference to the accompanying drawings, is illustrative of the embodiments described herein, and it is to be understood that the specific embodiments described herein are merely illustrative of the application and are not limiting of the application.

It will be understood that when an element is referred to as being "fixed to" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and/or" as used herein includes any and all combinations of one or more of the associated listed items.

The terms first, second, third and the like in the description and in the claims and in the drawings are used for distinguishing between different objects and not for describing a particular sequential order. Furthermore, the terms "comprising," "including," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion. For example, a series of steps or elements may be included, or alternatively, steps or elements not listed or, alternatively, other steps or elements inherent to such process, method, article, or apparatus may be included.

Only some, but not all, of the details relating to the application are shown in the accompanying drawings. Before discussing the exemplary embodiments in more detail, it should be mentioned that some exemplary embodiments are described as processes or methods depicted as flowcharts. Although a flowchart depicts operations (or steps) as a sequential process, many of the operations can be performed in parallel, concurrently, or at the same time. Furthermore, the order of the operations may be rearranged. The process may be terminated when its operations are completed, but may have additional steps not included in the figures. The processes may correspond to methods, functions, procedures, subroutines, and the like.

As used in this specification, the terms "component," "module," "system," "unit," and the like are intended to refer to a computer-related entity, either hardware, firmware, a combination of hardware and software, or software in execution. For example, a unit may be, but is not limited to being, a process running on a processor, an object, an executable, a thread of execution, a program, and/or being distributed between two or more computers. Furthermore, these units may be implemented from a variety of computer-readable media having various data structures stored thereon. The units may communicate by way of local and/or remote processes such as in accordance with a signal having one or more data packets (e.g., second unit data from another unit interacting with a local system, distributed system, and/or across a network).

Example 1

As shown in fig. 1 to 13, the present embodiment provides a flow cell antibody premixing device, which includes:

the box body 1 is vertically arranged and is provided with a cavity 101, and a through hole is formed in the surface of the box body 1;

The elastic movable piece 2 passes through the through hole and extends into the cavity 101, the elastic movable piece 2 is connected with the surface of the box body 1, the pipe diameter of the elastic movable piece 2 far away from the surface of the box body 1 is gradually contracted and is used for the pipette 3 to pass through and extend into the cavity 101, two gap gaps 201 are formed in the side wall of the elastic movable piece 2 to form two movable petals 202, when the pipette 3 is extruded without external force, under the elastic action of the elastic movable piece 2, the two movable petals 202 tend to extend and fit with the gap gaps 201 to enable the cavity 101 below the movable petals 202 to form a closed space, when the pipette 202 is extruded with external force, the two movable petals 202 are gradually unfolded in a direction deviating from each other, the lower ends of the two movable petals 202 are in a separated state from each other in a clinging state, and when the disposable tap 32 of the pipette 3 completely enters the cavity 101, the disposable tap 32 is limited by the lower ends of the two movable petals 202;

the annular body 4 is arranged on the inner wall of the elastic movable piece 2 and is positioned above the movable valve 202, and when the annular body 4 is extruded by external force, the annular body 4 deforms so that a closed space is formed by the cavity 101 below the annular body 4;

An EP tube 5, mounted in said chamber 101, for premixing the flow cell antibodies.

It should be noted that, the elastic movable member 2 is integrally formed as a semi-closed hollow circular truncated cone structure, and the upper surface thereof has an opening for being communicated with the outside, wherein the pipe diameter of the elastic movable member 2 far away from the surface of the box body 1 gradually contracts, specifically, the area S1 enclosed by the edge of the upper end of the elastic movable member 2 is larger than the integral area S2 formed by the end face of the lower end of the elastic movable member 2.

In this embodiment, the pipette 3 is a universal pipette, and includes a nozzle ejector 31 and a disposable nozzle cone 32, wherein the disposable nozzle cone 32 is mounted at the bottom end of the nozzle ejector 31.

In this embodiment, the ring body 4 includes:

the plurality of limiting strips 41 are distributed at intervals in a ring shape, a gap 410 is arranged between every two adjacent limiting strips 41, and in the embodiment, the gap 410 is a fan-shaped gap;

and the sealing strips 42 penetrate through the gaps 410 to respectively connect the two adjacent limiting strips 41 to form an annular closed loop, and when the sealing strips are extruded by external force, the annular body 4 deforms to enable the cavity 101 below the annular body 4 to form a closed space.

In this embodiment, the closing band 42 has an arc profile deviating from the limit bar 41, as shown in fig. 12 (a), which is a schematic view of the limit bar before being deformed by compression. When the sealing belt 42 is pressed by an external force, the sealing belt is stretched in a direction approaching to the limit strips 41 to enlarge the area of the area surrounded by the annular body 4, so as to provide a displacement space for the pipette 3, as shown in fig. 12 (b), and the clearance is enlarged after the limit strips are deformed by compression.

In this embodiment, the closing band 42 has a first side arc L1 and a second side arc L2, where the first side arc L1 is an inner side arc close to the surface of the limit bar 41, the second side arc L2 is an outer side arc deviated from the surface of the limit bar 41, and the arc length of the first side arc L1 is greater than the arc length of the second side arc L2.

As shown in fig. 10, fig. 10 (a) is a schematic diagram of the annular body before being pressed, when the annular body is not deformed, the area surrounded by the whole inner side edge formed by the limit strip 41 is P1, the whole inner side surface formed by the limit strip 41 is attached to the lower end surface of the nozzle ejector 31 of the pipette 3, fig. 10 (b) is a deformed schematic diagram of the annular body after being pressed, when the annular body is completely deformed, the area surrounded by the whole inner side edge formed by the limit strip 41 after being pressed is P2, the cross-sectional area of the upper end of the nozzle ejector is S3, so that S1> S3 > P2> P1 is satisfied, and the cavity of the elastic movable piece surrounded by the movable piece 202 can accommodate the disposable nozzle cone 32 of the pipette 3.

It should be noted that the sealing strip 42 is made of an elastic material, so as to be unfolded when being pressed to seal the gap 410 between the limiting strips 41.

In this embodiment, the ring body 4 further includes:

One end of the clamping piece 43 is connected with the side wall of the limit bar 41 deviating from the elastic movable piece 2. The end of the clamping piece 43 far away from the limiting bar 41 approaches the inner wall of the elastic movable piece 2, that is, the clamping piece 43 is wholly in an outward radial form, the clamping piece 43, the upper surface of the limiting bar 41 and the inner wall of the elastic movable piece 2 enclose a clamping gap 430 for the closed belt 42 to pass through, so that the tightness of the whole device is improved, and the clamping piece 43 is used for increasing the limiting effect of the clamping gap 430.

It should be noted that, in this embodiment, the two movable petals 202 are symmetrically distributed, so that the movable petals 202 are uniformly supported outwards when pressed to ensure that the pipette 3 moves vertically downwards, and avoid the pipette 3 touching the movable petals 202 due to asymmetric deformation.

In this embodiment, a groove 102 is provided on the inner side of the case 1 for fixing the EP tube 5, so that the disposable tip cone 32 having the antibody sucked therein can be inserted into the EP tube 5. The elastic movable piece 2 is positioned right above the groove 102, so that the pipette gun is convenient for premixing cell antibodies.

Example 2

This example was further modified based on example 1 to provide a flow cell antibody premixing device in which,

At least one side surface of the box body 1 is provided with visible glass 103, so that the operation process can be conveniently observed.

One side of the box body 1 is provided with a switch door 104, so that the EP pipe 5 is conveniently placed in the box body 1. The joint of the switch door 104 and the box body 1 is provided with a sealing ring, which is used for improving the tightness of the chamber 101 and reducing the risk of pollution of the antibody mixture.

The embodiment provides a flow cytometry antibody premixing method, which comprises the following steps:

s1, premixing preparation, namely opening an EP pipe cover, clamping an EP pipe body by forceps, putting the EP pipe body into a groove in a box body through a switch door, and closing the switch door;

s2, absorbing the antibody, namely mounting a disposable nozzle cone at the lower end of a nozzle ejector of the pipette, adjusting the liquid absorption capacity of the pipette, and absorbing the flow cell antibody;

S3, sealing and pipetting, namely vertically and downwards moving the whole pipetting gun from the upper end of the elastic movable piece, and when the disposable nozzle cone moves to the lower end of the cavity of the elastic movable piece, attaching the surface of the nozzle ejector to the inner wall of the limit strip. As shown in fig. 11 (a), in the plan sectional view of the lower end of the limit bar, as the tube diameter of the nozzle ejector of the pipette in contact with the inner wall of the limit bar gradually increases due to downward movement of the pipette, the limit bar is pressed to increase the fan ring gap, thereby increasing the area enclosed by the limit bar, wherein as in fig. 11 (b), in the plan sectional view of the upper end of the limit bar, the chamber is isolated from the external environment by the extrusion of the limit bar, and a closed environment is formed in the chamber. Due to the limiting effect of the clamping gap, in the process of increasing the fan ring gap, one end of the sealing belt is changed from vertical penetrating through the fan ring gap to oblique penetrating through the fan ring gap, and the whole stress of the sealing belt is in a straightened state so as to seal the fan ring gap. The area enclosed by the two limiting strips is increased, the movable petals are driven to be gradually unfolded outwards, the lower ends of the two movable petals are in a separated state from a clinging state, when the movable petals are completely unfolded, the upper end of the mouth tube ejector is limited by the limiting strips, the lower end and the middle end of the disposable mouth cone and the mouth tube ejector enter a sealed cavity, and antibodies in the disposable mouth cone are pushed into the EP tube along the tube wall of the EP tube;

S4, after the pipette is pipetted, the pipette is withdrawn, namely the whole pipette is vertically moved upwards to the nozzle ejector and is not extruded and limited by the lower ends of the two movable petals, as the middle end of the nozzle ejector is extruded and limited by the lower ends of the two movable petals, the lower ends of the movable petals are in a separated state, the disposable nozzle cone is favorably moved from the cavity to the lower ends of the cavities of the elastic movable parts, when the nozzle ejector is gradually retracted and extruded without external force, the sealing belt and the movable petals are reset under the elastic action of the elastic movable parts, and the two movable petals tend to extend and attach to the gap so that the cavity below the movable petals forms a closed space, and finally the pipette is removed from the elastic movable parts to finish one-time pipetting;

s5, repeating pipetting, namely repeating the steps S2-S4, sequentially adding the antibodies to be mixed into the EP tube until the last antibody is pushed into the EP tube, and repeatedly sucking a pipetting gun to mix the antibodies until the antibodies are completely mixed;

s6, collecting a mixed sample, namely opening a switch door, virtually covering a tube cover of the EP tube on a tube opening of the EP tube by using tweezers, avoiding sprinkling during taking out, clamping the tweezers above a tube body of the EP tube, taking the EP tube containing the antibody mixture out of a groove in a box body, and tightly covering the tube cover for later use.

In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings are merely for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the device or element being referred to must have a specific orientation, be configured and operated in a specific orientation, and therefore should not be construed as limiting the invention.

In the description of the present specification, reference to the terms "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiments or examples.

It will be apparent that the described embodiments are only some, but not all, embodiments of the application. Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application for the embodiment. The appearances of such phrases in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. Those of skill in the art will explicitly and implicitly understand that the embodiments described herein may be combined with other embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the application without making any inventive effort, are intended to be within the scope of the application.

Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made therein without departing from the spirit and scope of the invention as defined by the appended claims and their equivalents.

Claims

1. A flow cell antibody premixing device, comprising:

the box body (1) is provided with a cavity (101), and a through hole is formed in the surface of the box body (1);

The elastic movable piece (2) passes through the through hole and extends into the cavity (101), the elastic movable piece (2) is connected with the box body (1), wherein the pipe diameter of the elastic movable piece (2) far away from the box body (1) is gradually contracted, the pipe diameter is used for a pipette gun (3) to pass through and extend into the cavity (101), two gap gaps (201) are formed in the side wall of the elastic movable piece (2) so as to form two movable petals (202), and when no external force is extruded, the two movable petals (202) tend to extend and fit with the gap gaps (201) so that a closed space is formed in the cavity (101) below the movable petals (202);

the annular body (4) is arranged on the inner wall of the elastic movable piece (2) and is positioned above the movable valve (202), and when the annular body (4) is extruded by external force, the annular body (4) deforms to enable the cavity (101) below the annular body (4) to form a closed space;

an EP tube (5) mounted in the chamber (101) for premixing the flow cell antibodies.

2. The flow cell antibody premixing device according to claim 1, characterized in that the ring-shaped body (4) comprises:

The limiting strips (41) are distributed at intervals in a ring shape, and a gap (410) is formed between every two adjacent limiting strips (41);

and the sealing belts (42) respectively penetrate through the gaps (410) to connect the adjacent two limit strips (41) to form an annular closed loop.

3. Flow-cell antibody premixing device according to claim 2, characterized in that the closing band (42) has an arc-shaped profile deviating from the limit bar (41).

4. The flow cell antibody premixing device according to claim 2, characterized in that the ring-shaped body (4) further comprises:

one end of the clamping piece (43) is connected with the side wall of the limit strip (41) deviating from the elastic movable piece (2).

5. A flow cell antibody premixing device according to claim 3, characterized in that the closing band (42) has a first side arc and a second side arc, wherein the first side arc is an inner side arc close to the surface of the stop strip (41), the second side arc is an outer side arc deviating from the surface of the stop strip (41), the arc length of the first side arc being larger than the arc length of the second side arc.

6. The flow-through cell antibody premixing device according to claim 4, characterized in that the end of the clip (43) remote from the limit bar (41) approaches the inner wall of the elastic movable member (2).

7. The flow cell antibody premixing device according to claim 5, characterized in that the closing band (42) is made of an elastic material.

8. The flow cell antibody premixing device according to claim 1, characterized in that two movable lobes (202) are symmetrically distributed.

9. The flow cell antibody premixing device according to claim 1, characterized in that the inside of the tank (1) is provided with a groove (102).

10. Flow-cell antibody premixing device according to claim 9, characterized in that the tank (1) is provided with a visual glass (103) on either side.