EP0826420A1 - Heating device for laboratory glassware - Google Patents

Abstract

A heater for glass articles such as test tubes, flasks or beakers used in a laboratory, consists of a support (19) with a heating collar designed to receive inserts (7) of a heat conducting material, preferably aluminium, which are shaped to hold glass vessels. Each insert (7) is cylindrical, shaped to fit inside the heating collar, and has a cavity to receive a particular type of vessel. The outer surface of the collar has a mesh guard or an insulating jacket of rock wool or similar material to prevent any direct contact with it, and the collar itself has an electric heating element, a reflector and a fastening, preferably threaded, to adjust its diameter.

Description

The invention relates to an electric heating device for laboratory glassware, in particular test tubes, flasks, beakers, comprising a heating element in the form of a crown delimiting a housing opening in its upper part and capable of being closed, at any one of its ends, to using retractable sealing means.

The present invention relates to the technical field of manufacturers of equipment for experimentation in laboratory or during practical sessions in colleges and high schools.

Thus, the invention is more particularly part of the framework of experiments requiring a contribution of heat, a temperature rise.

The most commonly used material for this purpose is the spout Bunsen. This device has the advantage of being of a simple to use, convenient and inexpensive. He introduces however the disadvantage of running on gas which can be particularly dangerous when entrusted to young, inexperienced students.

Another particularly sensitive risk is at the level of maintenance and possibly obsolescence of the installations. Note that the supply lines for Bunsen burners consist of rubber hoses that have some lifetime. So it is essential to change them regularly and within the deadlines set by the manufacturer, respecting certain precautions under penalty of incurring risks of accidents whose severity is easily imaginable. he It should also be noted that if these basic precautions are actually taken, there remains the risk inherent in a upstream installation old or faulty. The maintenance of a installation is often difficult and awkward, and possible leaks may not be detected before incident. From a financial point of view, such a difficulty is translates into increased operating costs, bringing a nuance to the inexpensive nature of the use of beak Bunsen itself.

An alternative to the Bunsen burner has been proposed by the manufacturers laboratory equipment and practical work under the form of an electric heater.

This device makes it possible to approach performance and reach high temperatures, the heating temperature which can possibly be regulated. Said device makes it possible to heat various containers held in vertical position only. Besides a complex operation, the manufacture of this device the makes it unsuitable for mass production. The consequence is a high cost price.

More particularly, such a device comprises a body of cylindrical and hollow heating. It is, moreover, opening into its upper part. In addition, it has a ceramic envelope inside which are arranged heating resistors surrounding a well in particular metallic. Heating is provided by of said electrical resistances, the heating power can be adjusted. This device is powered electric directly connected to the mains.

This type of device proves to be inconvenient to use. His lack of flexibility combined with a high cost price not a suitable tool for practical work sessions high schools and colleges requiring, in most cases, preferably several devices, for multiple uses. So, the use of such a device is better suited to professional laboratories or research centers but very little in schools.

Also, the present invention aims to remedy the disadvantages mentioned above by proposing a heating device inexpensive, reliable, low-risk electrical the user and his environment, adaptable according to the type of equipment used and conditions of use.

To this end, the invention relates to a heating device laboratory glassware, in particular tubes with tests, flasks, beakers, comprising a heating body in crown shape defining a housing opening into its upper part and able to be closed, to any one of its ends, using sealing means retractable, characterized in that the heating body is defined by a heating collar, while the means retractable shutters are in the form of inserts made of thermal conductive material, preferably aluminum, and define, as the case may be and in combination with said heating collar, either a heating support or a container for receiving said glassware or the like.

According to the invention, said inserts are machined from a material thermal conductor, especially aluminum, and can adopt two preferential forms: on the one hand a tablet and on the other hand a cylinder.

The simplicity of the shape as well as the type of incoming material in the composition of such an insert, allow to propose advantageously retractable shutter elements little expensive because they are likely to be easily machined in a widely used metal.

Also, this ease of implementation makes it possible to propose inserts of various diameters and shapes, not only suitable to heating collars with different internal diameters, but also being suitable for heating various types of laboratory equipment, including test tubes, beakers, flasks, even tubes of columns of distillation.

In addition, some of these inserts are cleverly made so that they can be used for heating several types of containers. Indeed, the structure of heating collars is such that said closure elements retractable can be inserted inside the device, either by its upper end, or by its part lower. Thus, depending on the shape of the insert, it can can also be used for heating one or more test tubes when it is placed in the bottom of the collar, than to be used for heating a beaker by inserting said closure element retractable in the upper part of the device.

Advantageously, these inserts are mounted inside the heater and particularly disassembled easy, making it easy to use and versatile, perfectly suited to work sessions practices of high schools and colleges.

According to another characteristic of the present invention, the heating device comprises a support structure provided with means of tilting the heating collar. Such a characteristic advantageously allows to modify the inclination and / or orientation of said heating collar so as to adapt to the heating conditions of the different types of glassware.

This allows, in particular, to tilt test tubes in order to reduce the risk of projections or, at least, steer so as not to cause injury which may results in a significant increase in security.

When a heating collar is capable of being covered by a tube inside which circulates a fluid to be heated, a such a support structure can advantageously contribute to support, maintain and / or fix this tube, for example at within a facility, particularly a distillation facility.

• la figure 1 est une vue schématisée de dessus et partielle du dispositif de chauffage ;
• la figure 2 est une figure schématisée et en élévation du dispositif de chauffage;
• la figure 3 est une vue schématisée d'un exemple de réalisation de moyens d'obturation escamotables;
• la figure 4 est une vue schématisée et en coupe, similaire à la figure 3, correspondant à un autre mode de réalisation de ces moyens d'obturation escamotables ;
• les figures 5, 6, et 7 sont des vues de variantes de réalisations des pièces escamotables principales représentées figure 3 et 4;
• les figures 8 à 13 représentent des exemples d'utilisation des divers moyens d'obturation escamotables présentés figures 3 à 7 montées à l'intérieur du collier chauffant.

The invention is set out below in more detail with the aid of drawings representing only one embodiment.

• Figure 1 is a schematic top view and partial of the heating device;
• Figure 2 is a schematic and elevational figure of the heating device;
• Figure 3 is a schematic view of an exemplary embodiment of retractable closure means;
• Figure 4 is a schematic sectional view, similar to Figure 3, corresponding to another embodiment of these retractable closure means;
• Figures 5, 6, and 7 are views of alternative embodiments of the main retractable parts shown in Figure 3 and 4;
• Figures 8 to 13 show examples of use of the various retractable closure means shown in Figures 3 to 7 mounted inside the heating collar.

The invention relates to a heating device 1 for parts of laboratory glassware, including test tubes, beakers, flasks, distillation column tubes. This device has been shown schematically in Figures 1 and 2 of the attached drawings.

The heating device 1 comprises a heating body defining an interior heating volume 2.

In fact, this crown-shaped heating body defines a housing opening in its upper part and consists by a heating collar 3.

This heating collar 3 integrates in its volume one or more heating resistors supplied with electric current by via a connection cable 4 provided for this purpose. This cable can be connected to a power source possibly including means for mechanically regulating or electronically the temperature.

Thus, according to a first embodiment, the crown that defines the heating collar comes in the form of a annular ring formed by an electrical resistance internally wound and surrounded by a reflector.

According to another particularly advantageous embodiment, the heating collar 3 has an axial slot 5 which extends over its entire height. Furthermore, said heating collar 3 includes clamping means making it possible to modify the diameter by acting on the spacing between the two lips bordering said slot. Said clamping means can be presented, according to a preferred embodiment of the invention, in the form of a screw-nut system 6, such as visible in Figure 1.

Furthermore, according to the invention, said heating collar 3 can be closed at any of its ends using retractable sealing means 7. This makes it possible to define, as the case may be and in combination with said heating collar 3, either a heating support or a container for glassware reception.

Advantageously, the retractable closure means 7 are are in the form of inserts 7A, 7B made of conductive material thermal especially aluminum, adopting the form preferential, either of a pellet 7A, or of a cylinder 7B of section substantially adjusted to the internal section of the collar heating 3.

FIG. 3 represents an insert having a pellet shape 7A which is placed inside the heating collar 3, preferably in the upper or lower part of this last. In this regard, this pellet 7A has, at the edge peripheral 8, a shoulder 9 subdividing this patch 7A in two parts 10, 11, one of which 10 has a section substantially adjusted to that of the internal diameter of the collar heater 3, the other 11 being of increased section. Such a configuration facilitates the implantation of the patch 7A in the heating collar 3 since it suffices to bring the shoulder 9 of this pad 7A resting on the upper edge or edge bottom of this heating collar 3.

More particularly, when this pellet 7A is disposed in the lower part of the heater like the shown in FIG. 8, the heating volume thus defined comprises a flat bottom 12 and opens out in its upper part. he is of large capacity and can contain several pieces of glassware, in particular test tubes, coming to rest on the flat bottom 12. Keeping this insert in place inside a heating collar 3 with an axial slot 5 is made by tightening of said heating collar around part 10 of the pad 7A. In the particular case of a heating collar in the form of an annular ring, keeping the insert in place can be done using auxiliary fastening means such as that clip means secured to said insert and / or said heating collar.

When this type of insert in the form of a 7A pellet is arranged in the upper part of the heating device, this then serves as a heating support on which can take up pieces of glassware of various shapes. To optimize the thermal conduction between the containers and said pad 7A, its external surface 13 to the heating volume can be machined to have a shape complementary to that of said containers. As shown, respectively, Figures 7 and 8, this surface 13 will be flat in the case of the use of beakers, but will be concave if is to heat balloons.

FIG. 4 represents a cylinder-shaped insert 7B, of section approximately adjusted to the internal section of the heating collar 3 and advantageously provided with a rim peripheral 14 which is located in its lower part 15 in the framework of the embodiment represented in this FIG. 4, but which could very well be arranged in the upper border. Such a design is also shown in Figure 6. A such peripheral flange 14 is intended, here again, to take support on the upper edge or as appropriate the lower edge of the heating collar 3 and thus ensuring the correct positioning of this insert 7B in the latter.

According to the invention, such a cylindrical insert 7B can be provided with at least one housing 16 for the reception of a given glassware as shown in Figures 4 to 6, 10, 12 and 13. According to a preferred embodiment, the one or more housings 16 have a section, in particular cylindrical, approximately adjusted to the diameter of glassware, in particular test tubes, which they are intended to contain. We will note, by the way, that in case of multiple dwellings these can be of identical or different section.

It will be observed that this heating device is able to operate in the absence of said sealing means retractable 7. Under these conditions the heating collar 3 defines a heating volume leading to each of its extremities. This type of configuration then makes it possible to have inside said heating volume of the glassware parts, in particular a distillation column passing right through leaves said heating collar 3.

According to the invention, the heating device 1 comprises thermal protection means 17 avoiding direct contact with the heating collar 3 and therefore the risk of burns. According to a preferred embodiment, these means of thermal protection 17 are in the form of a grid 18 of diameter appreciably greater than that of the collar heating 3. One can still imagine equipping said collar heating 3 of an insulating protective jacket other such than a rock wool coat or equivalent.

The heating device 1 further comprises a structure support 19 provided with means 20 for tilting the collar 3. Such a characteristic ensures the heating, especially of test tubes under conditions similar to those provided by a Bunsen burner. According to a mode advantageous embodiment, said tilt means 20 are have the form of an arm 22 mounted articulated at least around a horizontal axis and at one of its ends 23, on said support structure 19, this arm 22 being provided, at its opposite end 24, of the heating collar 3. In this regard, this heating collar 3 can, according to a preferred embodiment, being drowned in a plastic shell constituting the end 24 of the arm 22.

As regards the support structure 19, this is present in the form of a base 25 on which can be mounted, directly, the arm 22. According to another mode of embodiment, also shown in Figure 2, on this base 25 can be erected a post 26 at the end upper 27 from which the arm 22 is hinged.

According to another possible embodiment, said means tilt 20 consists of a ball joint system integrated into the support structure, for example in the form of a simple base.

These tilt means 20 are further supplemented by clamping and blocking means for immobilizing said arm 22 or directly the heating collar 3 in a position data not related to support structure 19.

The use of heating collars such as those described above is particularly advantageous and adapted to this type of use, knowing that the maximum temperatures accessible by means of these collars are of the order of those reached with a Bunsen burner.

Another advantage of this invention is that the supply of the heating collars is done electrically allowing, not only an unrivaled flexibility in the choice of the working temperature, but also lets imagine a temperature control system so mechanical, and / or electronic in a more configuration evolved from the device.

Claims (10)

Glassware electric heater laboratory, in particular test tubes, flasks, beakers, comprising a heating body in the form of a delimiting crown a housing opening in its upper part and able to be closed at any of its ends, using retractable sealing means (7), characterized in that the heating element is defined by a heating collar, while that the retractable closure means (7) are present under the shape of inserts (7A, 7B) made of thermal conductive material, preferably aluminum, and define, as appropriate and in combination with said heating collar (3), ie a support or a container for receiving said glassware or other. Heating device according to claim 1, characterized by the fact that said sealing means retractable (7) consist of an insert in the form of a patch (7A) of cross-section adjusted to the internal cross-section of the heating collar (3). Heating device according to claim 2, characterized by the fact that a pellet (7A) comprises, in peripheral border (8), a shoulder (9) subdividing this patch (7A) in two parts (10, 11) one of which (10) has a section substantially adjusted to that of the internal diameter of the heating collar (3), the other (11) being of increased section, said shoulder (9) being intended to bear on the edge upper or lower edge of said heating collar (3). Heating device according to claim 1, characterized by the fact that the sealing means retractable (7) consist of an insert in the form of cylinder (7B) of section approximately adjusted to the section internal of the heating collar (3) and able to be provided with at least a housing (16) for receiving a type of glassware given, such as test tubes. Heating device according to claim 4, characterized by the fact that said cylinder-shaped insert (7B) has a peripheral rim (14) located in its lower part (15) or in its upper part and intended to rest on the lower edge or, as the case may be, the upper edge of the heating collar (3). Heating device according to any one of previous claims, characterized in that it includes thermal protection means (17), such as a grid (18) or a rock wool coat or equivalent, able to prevent direct contact with the collar heating (3). Heating device according to any one of previous claims, characterized in that it comprises a support structure (19) provided with means tilt (20) of the heating collar (3). Heating device according to claim 7, characterized by the fact that said tilting means (20) are in the form of an articulated arm (22), at less around a horizontal axis and at one of its ends (23), on said support structure (19), this arm (22) being provided, at its opposite end (24), with the heating collar (3). Heating device according to any one of previous claims, characterized in that the crown defined by said heating collar (3) is present in the form of an annular ring constituted by a internal electrical resistance wound surrounded by a reflector. Heating device according to any one of claims 1 to 8, characterized in that said collar heater (3) has an axial slot (5) as well as clamping means (6), preferably of the screw-nut type, allowing to modify the diameter.

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