Sublimation apparatus for protecting bees from insects

Abstract

The invention relates to a sublimation device for protecting bees from arthropod pests, which device comprises a kettle with a heated interior space, a lid, at least one heating device, and has a steam outlet tube. The invention is characterized in that the kettle (4) has a thickened bottom. In the thickened bottom two intersecting blind holes (11) are formed, such that the axes of the blind holes are at an angle to each other, wherein one of the blind holes leads directly from the bottom of the kettle or through the side wall of the kettle (4) to the heated interior space (6), and the other of the blind holes leads to a space outside the kettle (4). A bottom outlet tube (5) is arranged in the blind hole (11) leading to the space outside the kettle (4), and a steam release tube (2) is arranged in the blind hole (11) leading directly from the bottom of the kettle to the heated interior space (6). The end of the steam release tube (2) leading to the interior space (6) is arranged spaced apart below the lid (3).

Description

TECHNICAL FIELD

[0001] The present invention relates to an oxalic acid sublimation device suitable for use in a beekeeping site, the device comprising a kettle, at least one heating means, and a steam outlet pipe. The sublimation device according to the invention enables optimization of the sublimation process and greatly reduces the risk of oxalic acid condensation occurring in the outlet pipe. Thereby, the oxalic acid sublimation device allows easier, faster and more energy-efficient operation and requires less maintenance. BACKGROUND

[0002] The Asian honeybee mite is one of the most widespread pests in honeybees. It is very important to control (i.e. to keep the number below a given threshold) the varroa mite, because it damages the health of the bee colony by spreading viral diseases, and its uncontrolled proliferation often leads to the loss of the colony. One of the well-established methods of mite control is oxalic acid sublimation or oxalic acid vaporization (various terms are used; in English literature the term "vaporization" is used more frequently, while in Hungarian the method is widely referred to as "sublimation", the latter term is used hereinafter), in which crystalline oxalic acid (H2C2O4·2H2O) is sublimed at high temperature (typically 190-230 °C) in a sublimation device, and the generated steam is introduced into the interior of the beehive. When the high-temperature oxalic acid steam cools down and absorbs the ambient moisture, it condenses on the inner surfaces of the beehive and forms a thin layer of oxalic acid crystals, thus providing the mite control effect. Oxalic acid dihydrate starts to sublime at a temperature of 157 °C; if it is heated above 235-240 °C, it increasingly converts into formic acid, which is harmful to the bees.

[0003] Beekeepers apply a suitably configured device to perform the above-mentioned oxalic acid treatment. The prior art contains various sublimation solutions; the present invention improves the following solution: in which, in addition to the outlet pipe, the heated kettle is sealed during the sublimation process, the oxalic acid dihydrate is sublimed due to the overpressure generated in the kettle as a result of heating, and the oxalic acid steam is released from the kettle and introduced into the beehive through the outlet pipe of the kettle.

[0004] The prior art device is described with respect to Figures 1 and 2. The kettle body 4 of the device is made of metal with good heat conduction properties. The most commonly applied heating element is a tubular band heater (also known as a clamp heater) attached to the outside of the kettle body 4. A temperature sensor is arranged in an opening 7 arranged at the bottom of the cylindrical kettle body 4. This sensor is used to control the band heater by turning it on and off, thus maintaining the kettle body 4 at the desired temperature. The upper outlet pipe 9 through which the oxalic acid vapour is released under pressure is located close to the lid of the kettle body 4, arranged at the cylindrical side surface of the kettle body 4. It is necessary to arrange the upper outlet pipe 9 at the top of the kettle body 4, otherwise (i.e. if the outlet pipe is located at the bottom), because the crystallization water contained in the oxalic acid dihydrate placed in the internal space of the kettle body 4 reaches boiling first, the oxalic acid would leave the kettle body in liquid state. However, because the upper outlet pipe 9 starts from the upper part of the kettle body 4, the oxalic acid can only escape in the form of vapour. Two types of arrangement have become very popular. In one of the arrangements, the oxalic acid is released through the upper outlet pipe 9 (such a solution is applied in the Oxalika PRO device). In the case of another prior art solution, the oxalic acid leaves the device through a curved outlet pipe 10.

[0005] (such a solution is applied in the SzublimOx, Varroa-Ox, Provap, etc.).

[0006] In this technical solution, the curved outlet pipe 10 extending horizontally or at an angle from the top is bent down and, at the point where it reaches the bottom of the kettle body 4, it is bent again by 90 degrees, thus allowing the sublimation process to be performed using the device also through the lower inlet of the beehive (with landing board).

[0007] A similar solution is also disclosed in the patent document US 10,757,921 Bl. This solution is also applicable to band heating, where the oxalic acid vapour is discharged through an upper outlet pipe protruding from the lid of the kettle body.

[0008] Another prior art technical solution is presented in the utility model TW20190213843 specification, in which the cylindrical side surface is heated by a burner, the vapour outlet pipe passes along the cylindrical surface and (from the outside) under the kettle body, and has a curved shape at the bottom.

[0009] The devices applying the most widely used technical solution described above can have the following problems:

[0010] The application of a band heater is not optimal, because when oxalic acid is fed into the device, it falls to the bottom of the kettle 4 and takes heat away from it. As a result, the temperature sensor detects a drop in temperature and switches on the band heater. However, the heat provided by the band heater reaches the bottom of the kettle 4 after a long delay (the control has a large time constant) and, as experience has shown, this results in severe overheating, or in the case of PID temperature control, a slow rise in temperature and large temperature fluctuations.

[0011] In the first solution, because the upper outlet pipe 9 is attached to the relatively thin cylindrical side wall of the kettle 4, the upper outlet pipe cannot be sufficiently heated, i.e. the end of the upper outlet pipe has a tendency to cool down to a critical temperature at which a portion of the oxalic acid vapour flowing through the upper outlet pipe condenses, which (sooner or later) clogs the upper outlet pipe. Removing the oxalic acid condensate is a very time-consuming job. Unfavourable (cold or windy) weather further increases the frequency of clogging. The arrangement of the upper outlet pipe 9 is not optimal, because in order to ensure that the oxalic acid is released completely in vapour form, the outlet pipe must be located at the top of the kettle 4, whereas the end of the outlet pipe is preferably located at the bottom of the device, so that the oxalic acid can enter the beehive outlet above the landing plate. The result is the same as in the case of the second solution, i.e. the oxalic acid vapour is introduced into the beehive through the curved outlet pipe 10. The length of the curved outlet pipe 10 is located in the outside space, and its curved shape increases the tendency of the curved outlet pipe 10 to cool down, thus increasing its tendency to be clogged, while the curved shape makes the cleaning of the outlet pipe (which is also time-consuming in itself) more difficult and cumbersome. In addition to this, the bending, brazing and / or welding of the curved outlet pipe 10 is a labour-intensive and time-consuming operation.

[0012] Another disadvantage of the solution comprising the curved outlet pipe 10 is that, in order to achieve the curved shape required for it, the curved outlet pipe is made of soft metal, usually soft copper, which has a tendency to become softer over time and to break during use.

[0013] The object of the present invention is to eliminate the disadvantages of the prior art solutions, by providing an improved outlet pipe for releasing oxalic acid vapour, and to achieve a more optimal heating system, as well as a kettle having these improved features and being producible in series.

[0014] The present invention is based on the insight that, in the case of an outlet tube arranged near the bottom of the kettle, and in the case of an outlet tube that is as short as possible and has as simple a configuration as possible, while being made of a material that has sufficient strength, sublimation can be achieved in a more preferred manner through the hive outlet. We have also realized that the interior of the kettle can be configured in such a way that the boiling oxalic acid dihydrate cannot flow out through the outlet tube arranged in the bottom, i.e. so that only oxalic acid vapor can leave the device. According to our further insight, the provision of an outlet that extends as short as possible, and arranging it as close as possible to the heating means, results in advantageous temperature conditions, which can suitably ensure the temperature required to prevent the condensation of oxalic acid. SUMMARY

[0015] Thus, the technical solution according to the invention is a sublimation device for protecting honeybees from pests of the phylum Arthropoda, which device comprises a kettle having a heated interior space, a lid, at least one heating means, and has a vapor outlet tube. The invention is characterized in that the kettle has a thickened bottom. Two intersecting blind holes are formed in the thickened bottom, such that the axes of the blind holes are at an angle with respect to each other, wherein one of the blind holes leads directly from the bottom of the kettle or through the side wall of the kettle to the heated interior space, and the other of the blind holes leads to a space outside the kettle. A bottom outlet tube is arranged in the blind hole that leads to the space outside the kettle. Furthermore, a vapor release tube is arranged in the blind hole that leads directly from the bottom of the kettle to the heated interior space. The end of the vapor release tube that leads to the interior space is arranged spaced apart below the lid.

[0016] According to one preferred embodiment of the invention, the intersecting blind holes are perpendicular to each other.

[0017] According to another preferred embodiment of the invention, the vapor release tube is constituted by the blind hole that leads through the side wall of the kettle to the heated interior space, or a vapor release tube is arranged in the blind hole.

[0018] Another preferred embodiment of the invention is characterized in that the heating means is realized as at least one, and preferably at least two, heating cartridge, which heating cartridge is preferably arranged next to the bottom outlet tube.

[0019] In yet another preferred embodiment of the invention, the lid comprises an oxalic acid dropper, which is suitable for facilitating the feeding of oxalic acid into the device.

[0020] In another preferred embodiment of the invention, a hole suitable for accommodating a temperature sensor is arranged below the heated interior space of the kettle. BRIEF DESCRIPTION OF DRAWINGS

[0021] In the following, the sublimation apparatus according to the present application will be described with reference to the exemplary embodiments with respect to the accompanying drawings, in which

[0022] Figure 1 shows a cross-sectional view of a currently marketed prior art solution comprising a top-mounted straight outlet pipe,

[0023] Figure 2 shows a cross-sectional view of a currently widely used prior art solution comprising a curved outlet pipe,

[0024] Figure 3 a perspective cross-sectional view of the kettle body of the apparatus according to the present application is shown,

[0025] Figure 4 a cross-sectional view of the kettle body of the apparatus according to the present application is shown, and

[0026] Figure 5 a bottom outlet of the kettle body of the apparatus according to the present application is shown, as well as the location of the heating cartridges. DETAILED DESCRIPTION

[0027] Figures 1 and 2 show the configuration of the kettle body applied in the prior art apparatuses as described above in the background section. As can be seen in Figure 3 and Figure 4 the kettle body 4 of the sublimation apparatus according to the present application comprises a thickened bottom having a thickness of 7-50 mm; in the exemplary embodiment, preferably 30 mm. Two intersecting blind holes 11 are formed in the thickened bottom of the kettle body 4 such that the axes of the blind holes 11 are at an angle with respect to each other, advantageously, the two blind holes are perpendicular to each other, wherein one blind hole leads directly or through the side wall of the kettle body 4 to the heated interior space 6, and the other blind hole leads to the space outside the kettle body 4. A bottom outlet pipe 5 is arranged in the (preferably horizontal) blind hole 11 leading to the space outside the kettle body 4. The bottom outlet pipe 5 is suitable for transporting oxalic acid vapour to the hive entrance. In the exemplary embodiment, at least one, but preferably two heating cartridges 8 are arranged on each side of the bottom outlet pipe 5 (see Figure 5), so that the heating cartridges surround the bottom outlet tube 5, heating the latter from close range. The heating device can also be a belt heater, since by arranging the tubes according to the invention, the required function can also be achieved with a belt heater. Further, in the (preferably vertical) blind hole 11 leading directly to the heated interior space 6, the steam release tube 2 is arranged. In the case where the (advantageously vertical) blind hole 11 is formed in the side wall of the kettle body 4, the invention can be implemented such that the steam release tube 2 is constituted by this blind hole 11. The air release tube 2 and the bottom outlet tube 5 can be fixed in the blind hole 11 by pressing, screwing, or any other means apparent to the person skilled in the art. Due to the intersecting configuration of the blind hole 11, oxalic acid steam can escape freely through the blind hole under pressure. The length of the steam release tube 2 is chosen such that it does not come into contact with the lid 3 attached to the kettle body 4, i.e. the steam release tube is spaced apart from the lid. In the case where a blind hole 11 leading to the interior space 6 is formed in the side wall of the kettle body 4, this hole communicates with the interior space 6 through an opening provided spaced apart from the lid 3 below the lid. This configuration ensures that oxalic acid steam can enter the steam release tube 2, and at the same time, liquid oxalic acid boiling in the water of crystallization due to heating can be prevented from flowing out of the tube. Advantageously, an oxalic acid drip tube 1 is provided in the lid 3 to facilitate the feeding of oxalic acid into the apparatus. After the oxalic acid has been fed into the apparatus, the drip tube 1 is sealed, so that the kettle body 4 can be pressurized and oxalic acid steam can only escape through the bottom outlet tube 5. Advantageously, the hole 7 is provided below the heated interior space 6 of the kettle body 4, close to the heating device (in our example, two heating cartridges 8, which are opened or closed based on the measured temperature value).

[0028] The apparatus according to the invention has the following advantages:

[0029] - By means of the temperature sensor located directly below the heated interior space 6, a temperature drop caused by the feeding of oxalic acid dihydrate into the heated interior space 6 is detected, thereby opening the heating cartridges 8. In this way, a fast reaction time (low time constant) temperature control can be achieved.

[0030] - The steam release tube 2 is located in the heated interior space 6, regardless of the temperature of the outer space, so it does not cool down and oxalic acid cannot condense in it.

[0031] - The bottom outlet tube 5 starts from the thickened bottom of the kettle body 4 and is located exactly between the two heating cartridges 8, so it does not cool down easily and therefore oxalic acid cannot condense in it.

[0032] - the bottom outlet pipe 5 is easy to machine since it is configured separately from the release pipe and is free from bends / folds. Therefore, advantageously, the bottom outlet pipe is made of a solid material (e.g. copper, brass, etc.) so that it can also withstand the mechanical loads caused by the weight of the device during operation, thus the bottom outlet pipe is suitable to support the overall weight of the device.

[0033] - the solution relating to the bottom outlet pipe 5 allows the sublimation treatment of the bee colony through the hive outlet.

[0034] - the device according to the present application can be manufactured applying general CNC machining techniques, i.e. without the need for handwork, brazing or welding.

[0035] - in case of larger series continuous manufacturing, the configuration can be modified so that the steam release pipe 2, which is shown separately machined in the figures, can also advantageously be manufactured by molding, or even as a cavity formed in the wall of the kettle 4.

Claims

1. A sublimation device for protecting honey bees from arthropod pests, said device comprising a kettle having a heated interior space, a lid, at least one heating means, and having a steam outlet tube, characterized in that, The pot body (4) has a thickened bottom in which two intersecting blind holes (11) are formed, the axes of which are at an angle to each other, wherein one of the blind holes leads directly from the bottom of the pot body (4) or through the side wall of the pot body (4) to the heated interior space (6), and the other of the blind holes leads to a space outside the pot body (4), and a bottom outlet tube (5) is arranged in the blind hole leading to the space outside the pot body (4), and a steam release tube (2) is arranged in the blind hole (11) leading directly from the bottom of the pot body to the heated interior space (6), wherein the end of the steam release tube (2) leading to the interior space (6) is arranged spaced apart below the cover body (3).

2. The sublimation apparatus of claim 1, wherein, The intersecting blind holes (11) are perpendicular to each other.

3. The sublimation apparatus of claim 1, wherein, The steam release tube (2) is formed by the blind hole (11) leading through the side wall of the pot body (4) to the heated interior space (6).

4. The sublimation apparatus of claim 1, wherein, The steam release tube (2) is arranged in the blind hole (11) leading through the side wall of the pot body (4) to the heated interior space (6).

5. The sublimation apparatus of claim 1, wherein, The heating device is implemented as at least one heating cartridge (8) arranged next to the bottom outlet tube (5).

6. The sublimation apparatus of claim 1, wherein, The cover body (3) comprises an oxalic acid dropper (1) which is suitable for facilitating the feeding of oxalic acid into the apparatus.

7. The sublimation apparatus of claim 1, wherein, A hole (7) suitable for accommodating a temperature sensor is arranged below the heated interior space (6) of the pot body (4). A hole (7) suitable for accommodating a temperature sensor is arranged below the heated interior space (6) of the pot body (4).

Images