Device for heating a container

Abstract

Device for heating a container Assembly formed of a container and a device for heating the container, the heating device comprising: - a housing; - a heating element contained in the housing and defining a cavity for receiving the container, intended to heat the latter by dry conduction. Figure for the abstract: Fig. 4

Description

Title of the invention: Device for heating a container Technical field

[0001] The present invention relates to a device, and more generally to an assembly, for enabling the controlled heating of a container. In particular, the present invention relates to a device for heating a test sample, for example a biological material placed in solution. Prior art

[0002] There are many heating devices designed to heat a container and which can operate by conduction or convection. Examples include bottle warmers, wax heaters, thermostatic baths, electric heating mantles, or even hot plates. These different devices are used in extremely varied contexts and conditions of use. In particular, laboratory equipment such as thermostatic baths, electric heating mantles or laboratory hot plates require careful handling. Furthermore, this equipment has a significant cost. Common equipment, such as wax heaters or bottle warmers, is very limited in its use and relatively imprecise in the temperatures reached.

[0003] However, in the case where one wishes to carry out tests involving chemical reactions, an inaccuracy in the temperature is likely to lead to variability in the results, which is detrimental to their interpretation and the reliability of the test.

[0004] In addition, devices operating on the bain-marie principle involve a greater risk of burns in the event of accidental spillage, due to the projection of the liquid constituting the bath. Statement of the invention

[0005] There is a need for a heating device for heating a container in a controlled manner, which is compact, lightweight and accessible to the general public, and which is safe to use.

[0006] There is also a need for an improved heating device for quickly reaching a given temperature.

[0007] There is further a need for a device for maintaining a given temperature without exceeding it.

[0008] The invention aims to meet all or part of these needs. Summary of the invention

[0009] The subject of the invention is an assembly formed of a container and a device for heating the container, the heating device comprising:

[0010] -a housing;

[0011] - a heating element contained in the housing and defining a receiving cavity of the container, intended to heat the latter by dry conduction.

[0012] The assembly according to the invention advantageously makes it possible to limit the risks of burns, due to the absence of liquid at the interface between the container and the heating element. Thus, in the event of accidental overturning of the device, if the container is closed, there is no risk of projection, except in the event of breakage of the container.

[0013] The device according to the invention can make it possible to control the temperature to which the container is heated quickly and precisely, and by lower value.

[0014] Such a device can also make it possible to reach a given temperature in a reduced time.

[0015] Generally speaking, unlike bottle warmers, wax warmers or water baths, conduction by dry contact, in other words without heating fluid, and with low inertia makes the temperature rise much faster. In addition, the invention provides a container heating assembly that is compact, lightweight and safe for the user.

[0016] The cavity may have a shape complementary to the external shape of said container. This makes it possible to maximize the heat exchange surface between the container and the heating element.

[0017] Preferably, more than 80% of the container is inserted into the cavity, better still more than 90% of the container is inserted into the cavity. This makes it easier to hold the container in the device, and covering the container with a hood reduces the risk of breakage of the container in the event of accidental overturning of the device. This also makes it possible to have a large exchange surface and a more uniform temperature of the wall of the container.

[0018] Such an assembly makes it possible in particular to obtain a compact assembly while maximizing thermal exchanges and thus improving thermal performance.

[0019] The container may in particular be a tubular container having an external diameter greater than or equal to 2 cm and less than or equal to 3 cm.

[0020] The assembly is particularly suitable for carrying out tests on samples, quickly and easily, without the need for laboratory equipment.

[0021] The heating element may comprise a heating sleeve composed of a ceramic-coated heating resistor.

[0022] Generally, the resistor is preferably covered with a material with low mass and low thermal inertia.

[0023] The heating sleeve may be a split collar.

[0024] The heating element may include a heating sleeve clamp, the clamp adjusting the inner diameter of the heating sleeve so that the container fits into the cavity of the heating element with a sufficiently small clearance to allow heating of the container by dry conduction. Heat losses are advantageously limited. The collar can be adjusted by tightening a screw, a temperature sensor such as a thermistor being positioned in direct contact with said screw. Such an arrangement makes it possible to have a good image of the temperature of the collar with the temperature sensor.

[0025] In particular embodiments, the assembly comprises a temperature regulator configured to heat the container to a predefined temperature, and optionally maintain this predefined temperature for a predetermined period of time, the temperature being in the range [70°C; 110°C], better still in the range [90°C; 100°C], and preferably, this temperature is maintained for a period of time greater than or equal to 3 minutes and / or less than or equal to 10 minutes.

[0026] This temperature control can help limit the risk of burns by not exceeding certain temperatures. The control can also help not to exceed temperatures that could damage the contents of the container by heating to too high a temperature.

[0027] The temperature controller may be a PID (proportional, integral, derivative) controller. In particular, the PID controller may have a proportion gain Kp of between 0.2 and 0.4 and a proportion gain Ki of between 0.05 and 0.15.

[0028] The housing may comprise a base having an opening through which the container is intended to be introduced into the base, and a cover hinged on the base between an open position and a closed position.

[0029] In particular, the cover can be pivotally mounted around an axis of rotation substantially parallel to an axis of insertion of the container into the base and into the cavity of the heating element.

[0030] In the closed position, the hood retains the container in the housing, and limits, or even blocks, access to hot surfaces of the device or container.

[0031] Furthermore, the heating device may comprise a contact switch arranged such that the closed position of the switch is triggered by rotation of the cover, when the latter pivots into the closed position, the switch being configured such as to prevent heating when the switch is open.

[0032] Thus, heating of the container can be conditioned by the closing of the hood, improving user safety. This also makes it possible to limit energy consumption, by stopping the heating as soon as the device is opened. This can also limit handling, if necessary, by avoiding having to press a button to stop the heating.

[0033] In embodiments of the invention, the cover is attached to a rod positioned within the housing and having a stop element for contacting with the switch when the hood is in the closed position, the switch being in the closed position when it is in contact with the stop element.

[0034] The assembly may further comprise a thermally insulating container closure cap. Heat losses are advantageously limited, and handling of the container is made easier.

[0035] The cover may have a side opening, so that it can engage on a container not completely inserted into the cavity. This makes it possible to easily maintain access to the container cap to extract it from the device, once the cover is in the open position.

[0036] The heating element may be arranged in a support thermally insulating the heating element from the housing, the support being fixed to an upper part of the housing, and in particular when the housing comprises a base and a cover, the support is fixed to an upper part of the base.

[0037] In order to ensure electrical safety of the heating device, a fuse and an earth wire may be positioned in a lower part of the support. In particular, the fuse may be a thermofuse or a resettable safety thermostat, also called a resettable Klixon.

[0038] The bottom of the support may comprise a slot having the general shape of an angular sector (i.e. a quarter), the apex of the angular sector being located substantially in the center of the bottom of the support. Preferably, the slot comprises a widening at the apex of the angular sector, the opening angle of the angular sector being greater than or equal to 15° and less than or equal to 45°. Brief description of the drawings

[0039] The invention may be better understood by reading the detailed description which follows, a non-limiting example of its implementation, and by examining the attached drawing, in which

[0040] [Fig.l] is a longitudinal section of an example of a heating device according to the invention,

[0041] [Fig.2] represents a heating element,

[0042] [Fig.3] represents the heating device in the open position (Fig 3b) and in closed position (Fig 3b),

[0043] [Fig.4] is an exploded view of the heating device,

[0044] [Fig.5] shows in cross section the heating device,

[0045] [Fig.6] shows a top view and a bottom view of the element support heating,

[0046] [Fig.7] is a graph illustrating an example of a heating law.

[0047] In the remainder of the description, identical elements or elements with similar functions bear the same reference sign. Their description is not repeated with respect to each of the figures, only the main differences between the embodiments being mentioned. Detailed description

[0048] Figures 1 to 6 illustrate an assembly 1 according to the invention, comprising a container 2 and a device 3 for heating the container.

[0049] The heating device 3 comprises a housing 30 having a base 35 and a cover 36, and a heating element 32 contained in the housing, defining a receiving cavity 34 of the container. The cavity 34 is arranged so as to allow the container to be heated by dry conduction, that is to say without liquid at the interface between the heating element and the container, unlike the water bath. The base comprises an upper part 351 and a lower part 352.

[0050] The container 2 may be, as illustrated, a tubular container, preferably with rotational symmetry. Preferably, the container has a maximum external diameter D greater than or equal to 2 cm and less than or equal to 3 cm.

[0051] The container may in particular be a test tube or a sample tube, in particular a standard one.

[0052] The container may be made of mineral glass or thermoplastic material resistant to the temperature of use, in particular polypropylene or polyethylene.

[0053] Preferably, the container is made of a material resistant to the temperature of use and chemically neutral.

[0054] By chemically neutral is meant a material which does not produce any chemical reaction when the latter is in contact with a composition intended to be introduced into the container.

[0055] Preferably, the container is made of a transparent or semi-transparent material.

[0056] In some embodiments, the container may be made of a metal alloy, which may be opaque. The nature of the material of the container may improve the conduction of heat within the container.

[0057] The container may in particular be intended to contain a solution for carrying out a chemical test, requiring the solution to be heated to a given temperature and / or for a given duration.

[0058] The biological material to be analyzed can be inserted into the container, for example consisting of capillary fibers.

[0059] In particular, the assembly according to the invention can be arranged so as to allow the chemical analysis of hair.

[0060] The container may be closed by a thermally insulating sealing plug 22, as illustrated in [Fig.l]. In particular, the plug may be formed, at least in part, by a thermally insulating foam 22i. The cap may comprise a central part 222, for example made of elastomer or a non-cellular and flexible plastic material, which is fixed on the neck of the container to close it, and a concentric outer part, formed by said insulating foam 22i, which extends over more than the height of the central part.

[0061] The height of the container and that of the cavity are such that preferably more than 70%, better still more than 80%, even better still more than 90% of the container is contained in the cavity 34.

[0062] The outer surface of the part of the container received in the cavity can come into direct contact with the heating element 32, apart from the insertion clearance.

[0063] As illustrated in [Fig.2], the heating element 32 may comprise a heating sleeve 38 composed of a ceramic-coated resistor.

[0064] The heating element 32 can be connected to a power supply, via a connector 62.

[0065] The heating sleeve 38 may be a split collar, as illustrated.

[0066] A clamp 40 can grip the heating sleeve 38, the clamp adjusting the inner diameter d of the heating sleeve at manufacture so that the container fits into the cavity of the heating element with a sufficiently small clearance to allow heating of the container by dry conduction and insertion or extraction of the container without forcing.

[0067] The clamping collar 40 can in particular be adjusted by tightening a screw 42. In addition, a thermistor 44 or any other temperature sensor can be positioned in direct contact with said screw 42. A ground wire 74 can be connected to the screw 42, to guarantee electrical safety.

[0068] The heating element 32 may be disposed in a support 48 thermally insulating the heating element from the housing, as illustrated. In particular, the support 48 may comprise a thermal insulator 46 coating, at least partially, the heating element.

[0069] A thermal fuse 66 is preferably positioned in the lower portion of the support.

[0070] The bottom of the support may comprise a slot 68 having the general shape of an angular sector. The apex of this sector is preferably located substantially in the center of the bottom of the support. In addition, the slot 68 may comprise a widening 70 at the apex of the sector. The opening angle 0 of the angular sector may be greater than or equal to 15° and less than or equal to 45°. Such a support 48 allows deformability and the possibility of adjusting its internal diameter by tightening a screw 72 engaging two opposite uprights of the support 48. The latter can thus be tightened onto the heating element.

[0071] The support 48 can be fixed, as illustrated in [Fig.6], to an upper part of the housing 30, in particular to the upper part 351 of the base.

[0072] The support 48 is for example screwed to the upper part of the base 35, by means of screws 50, as illustrated in [Fig.4].

[0073] The cover 36 is movable, as shown in [Fig. 3], between an open position shown in Figure 3a and a closed position shown in Fig 3b.

[0074] The cover 36 may include a lateral opening 52.

[0075] The cover 36 can be mounted pivoting about an axis of rotation X substantially parallel to an insertion axis Y of the container in the cavity of the heating element. The cover pivots in a horizontal plane.

[0076] A contact switch 54 may be positioned in the heating device, as seen in [Fig. 5], this switch being for example fixed on the lower part 352 of the base, the switch 54 being arranged so that the closed state of the switch is triggered by rotation of the cover, when the latter pivots into the closed position, the control circuit of the heating element being configured so as to prevent heating when the switch is open.

[0077] The cover 36 may be fixed to a rod 56 positioned inside the housing and comprising a cam 58 intended to come into contact with the switch 54 when the cover is in the closed position, the switch being brought into the closed position by the cam 58.

[0078] Preferably, the device comprises a temperature regulator 60 configured to control the heating element so as to heat the container to a predefined temperature, and maintain this predefined temperature for a predetermined period of time, the temperature being in the range [70°C; 110°C], better still in the range [90°C; 100°C] for a period of time greater than or equal to 3 minutes and / or less than or equal to 10 minutes.

[0079] The temperature regulator 60 may comprise a microcontroller, which controls, for example, via an optocoupler a power component, making it possible to control the electrical supply of the heating element as a function of the measurements detected by the thermistor and the regulation law. The power component may be an optotriac.

[0080] The heating device may include a visual or audible indicator 64 informing the user of the operating status of the device. For example, the visual or audible indications may indicate that the device is heating, that the predefined temperature has been reached, that the predetermined period of time has elapsed, that the device is open. In particular, the visual or audible indications may emanate from a screen, an LED, or a buzzer.

[0081] The temperature regulator may in particular be a PID regulator (proportional, integral, derivative), whose proportion gain Kp is notably between 0.2 and 0.4 and therefore the proportion gain Ki is notably between 0.05 and 0.15.

[0082] The PID regulator makes it possible to have a heating law in the form of a ramp R. The graph in [Fig.7] shows, with a measurement step of 500 ms, curves C1, C2, C3 which trace the evolution of the temperatures obtained at the level of the contents of the container over time during operation of the heating device illustrated in figures 1 to 6. Curves C1 to C3 were obtained during three successive tests aimed at heating the container to a set temperature of 100°C and then maintaining this temperature for a period of at least 5 minutes.

[0083] Curve C4 corresponds to the difference between curves C1 and C3. These curves show that the predefined temperature of 100°C can be reached relatively quickly and maintained, with a degree of accuracy of approximately 10°C.

Claims

Claims

1. Assembly (1) formed of a container (2) and a device (3) for heating the container, the heating device comprising: - a housing (30); - a heating element (32) contained in the housing and defining a receiving cavity (34) of the container, intended to heat the latter by dry conduction.

2. Assembly according to the preceding claim, the container (2) being a tubular container having an external diameter (D) greater than or equal to 2 cm and less than or equal to 3 cm.

3. Assembly according to one of claims 1 and 2, in which the housing (30) comprises a base (35) having an opening through which the container is intended to be introduced into the base, and a cover (36) articulated on the base between an open position and a closed position.

4. Assembly according to claim 3, the cover (36) being pivotally mounted around an axis of rotation (X) substantially parallel to an axis of insertion (Y) of the container in the base and in the cavity of the heating element.

5. Assembly according to one of claims 3 and 4 in which the heating device comprises a contact switch (54) arranged so that the closed position of the switch is triggered by rotation of the cover, when the latter pivots into the closed position, the switch being configured so as to prevent heating when the switch is open.

6. Assembly according to the preceding claim, the cover being fixed to a rod (56) positioned inside the housing and comprising a stop element (58) intended to come into contact with the switch when the cover is in the closed position, the switch being in the closed position when it is in contact with the stop element.

7. Assembly according to any one of claims 3 to 6, the cover (36) comprising a side opening (52).

8. An assembly according to any preceding claim wherein the heating element (32) comprises a heating sleeve composed of a ceramic-coated heating resistor.

9. Assembly according to the preceding claim, the heating sleeve being a split collar.

10. An assembly according to one of claims 8 and 9, the heating element comprises a clamping collar (40) of the heating sleeve, the clamping collar adjusting the inner diameter of the heating sleeve so that the container fits in the cavity of the heating element with a sufficiently small clearance to allow heating of the container by dry conduction.

11. Assembly according to the preceding claim, the collar being adjusted by tightening a screw, a temperature sensor (44) such as a thermistor being positioned in direct contact with said screw.

12. An assembly according to any one of the preceding claims, comprising a temperature regulator (60) configured to heat the container to a predefined temperature, and optionally maintain this predefined temperature for a predetermined period of time, the temperature being in the range [70°C; 110°C], better still in the range [90°C; 100°C], preferably, the temperature being maintained for a period of time greater than or equal to 3 minutes and / or less than or equal to 10 minutes.

13. Assembly according to claim 12, the temperature regulator (60) is a PID (proportional, integral, derivative) regulator, the proportion gain Kp of which is in particular between 0.2 and 0.4 and the proportion gain Ki of which is in particular between 0.05 and 0.

15.

14. Assembly according to any one of the preceding claims comprising a plug (22) for closing the thermally insulating container.

15. An assembly according to any one of the preceding claims, the heating element being arranged in a support (48) thermally insulating the heating element from the housing, the support being fixed to an upper part (35i) of the housing, in particular when the housing comprises a base and a cover, the support is fixed to an upper part of the base.

16. An assembly according to the preceding claim wherein a fuse (66) and an earth wire are positioned in a lower portion of the holder.

17. Assembly according to one of claims 15 and 16, the base of the support comprising a slot (68) having the general shape of an angular sector, the apex (70) of the angular sector being located substantially in the center of the base support, preferably the slot comprising a widening at the apex of the angular sector.

18. Assembly according to the preceding claim, the opening angle (0) of the angular sector being greater than or equal to 15° and less than or equal to 45°.

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