DE3639717A1 - Device for generating water vapour - Google Patents

Abstract

In devices for generating water vapour to humidify the air it is usual to heat the water indirectly by heater elements or to pass electricity through the water by means of electrodes. Both methods suffer from high consumption of energy and an evaporation capacity that depends on the proportion of lime in the water. In the case of the heater elements, this is due to the limescale deposits and the resultant poorer heat transfer, and in the case of electrodes, the limescale deposits cause an increase in the contact resistance. The invention remedies both these problems regarding energy consumption and the demand for uniform output by having the container with the water positioned at least partly in a microwave field generated by a microwave generator. Direct absorption of energy by the water molecules occurs, so that lime in the water can have no effect on the heating up. Furthermore, at the surface the separation of water molecules into the vapour phase is promoted, providing savings in energy as well in a surprising manner.

Description

The invention relates to a device for generating of water vapor, especially for humidification, be standing out of a container filled with water, the is provided with water vapor outlet openings and in which thermal energy is added to the water.

Devices for generating water vapor used especially for air humidification. Thereby fluctuations in natural humidity balanced or generally higher moisture level created. This has both beneficial out effects on humans, since its mucous membranes he can respond to infectious attacks as well on wooden objects, technical devices, food as well as production processes.  

This is how drying out of wooden objects and an associated crack formation prevented. At technical devices are electrostatic charging and material embrittlement prevented. As an an example telecommunications technology should be mentioned here. At Lebensmit tle, especially dairy products, becomes a constant Maturation process and a constant water content aims. In production processes, the textile to call industry where a constant humidity makes the fibers supple, which makes the trouble-free processing at high ar speed is extremely important. Finally, in the paper industry, paper Processing prevents static charges.

In addition, there are also areas of application for Devices for generating steam, in which air humidification is not the primary focus. Steam saunas, medical content are worth mentioning lation devices and steam ironing devices.

There are already different principles of humidification device or the generation of water vapor known, the the generic terms evaporation, atomization and evaporation  can be summarized.

Evaporators suck or blow room air with the help of a Fan through or over constantly wetted with water Material of various qualities, the Air enriches with moisture. This creates Ver evaporative cold. The disadvantages of an evaporative air humidifiers are the high indirect energy consumption by lowering the room temperature, moreover they are unsanitary, because ge sucked in room air long bacteria, viruses and germs into the water and the Fan generates disturbing noises and drafts. The Performance is only dependent on the room temperature low.

Atomizers smash the water into microfine moles coolers (aerosols) that enrich the room air with water. Evaporative cold also arises here. The disadvantages of the atomizing humidifier are like evaporators the high energy consumption by lowering the room temperature rature, the formation of bacteria, viruses, etc. and that particularly loud noise. Because the minerals in the water are released into the room air, this happens so-called lime precipitation. There are systems knows who mine the water to be atomized beforehand  Realize, but the effort is usually quite large and only partially effective.

Evaporators heat the water and give rise to it the steam to the room air. Lowering the room temperature temperature does not occur because no evaporative cooling ent stands. Evaporators work silently, germs become killed by boiling and minerals remain in the Device. Some of the disadvantages, as with the after whose principles exist in working humidifiers thus do not occur with evaporators. Therefore but suffer the previously known after the evaporation principle working devices at a very high Energy consumption (electricity consumption) and other system contingent defects.

DE-PS 20 14 338 is a device for Generation of water vapor for air humidification known where the water in a container is there is heated by that electrodes in the water ge dives and electricity is passed through. In addition to the Ge Drive that the electrodes calcify and therefore none Power line is more possible, there is the undesirable Possibility of a detonating gas development and an electro chemical decomposition of the electrodes. Besides, that is Conductivity of the water varies widely as it  depends on the salt composition.

From DE-PS 26 42 911 is a humidifier direction known in which a heating element in a Evaporation chamber is arranged. With this warmth The heat gradient between the heating is transferred element and the water exploited. Because the heating element for this purpose a significantly higher temperature than the boiling water takes on, it comes to the waiter area for limescale. These lead to a ver deterioration of the heat transfer, so that now with a even higher temperature must be worked. The Maintenance is accordingly high and the le Life of such heating elements is low. A driving with demineralized water is very expensive.

The invention has for its object a Vorrich device for generating water vapor, in particular for To create humidification, which in addition to a ver reduction of nucleation as well as drafts and noise low energy consumption and low heat consumption lusts, avoids calcifications and thus a safe, low-maintenance operation.

This object is achieved in a device for production of water vapor according to the preamble of claim 1  by the features specified in the characterizing part solved.

The thermal energy is in front of the invention direction supplied by a microwave field. Because what is a polar medium, the water molecules when trying to face the high frequency changes to adapt the microwave field to thermal vibr staggered. In doing so, they absorb a large one Part of the energy present in the microwave field. Like this with the heating does not go from a discrete heating element, but is in each of the molecules themselves evoked. There are large temperature gradients do not follow.

So there is no hard-encrusted limescale stanchions. A key cause of a gradual the resulting reduction in performance is thus eliminated. This applies even if it emerges from the water accumulated lime components on the tank bottom or put down on the walls. Of particular note is that significantly lower than discrete heating elements Energy consumption, which is surprisingly one poses. This is precisely because it is after the first Principle of thermodynamics may not play a role,  the way in which the energy is supplied to a medium.

With the microwave irradiation of water appears however, a particularly favorable detachment effect of the Adjust surface molecular layers. This leads already to an intense evaporation without it a temperature increase in the total amount of water up to to the boiling point.

Apart from that, however, the microwave energy also better concentrate on the medium of water. Inso there is no unwanted warming of the surroundings air or surrounding objects instead.

In a development of the invention, the container made of a non-metallic, non-polar material, preferably made of plastic, glass or ceramic.

This selection of materials will heat the Avoided container walls. In the aforementioned This leads to a reduction in radiation losses and to a concentration of microwaves energy on water content.

In a first embodiment of the invention, this is the  Microwave field generating generator inside the Container arranged.

This configuration results in a high energy concentration tration reached. In addition, only a small Ab shielding effect is required because most of the micro wave energy already on the way through the water is absorbed. In addition, the Er generation of microwaves inevitable heat loss released directly to the water and leads to it Way to an albeit moderate increase in temperature.

In a further development of this version, the Microwave field generating generator radiation opening conditions that point in different directions.

This configuration contributes to a homogeneous heating and improves efficiency.

In a modified embodiment, this is the Microwave field generating generator outside the Container arranged.

Since here the available volume for the Housing the microwave generator is larger,  offers this possibility for devices in particular high performance.

In a further development of this embodiment, the the generator generating the microwave field into several Ge nerator units divided ver around the container divides are arranged.

This configuration lends itself to high-performance projects devices for the production of water vapor as they are needed in the industry. The one after the next education subdivision ensures that a homogeneous microwave field distribution is achieved and so a correspondingly homogeneous heating takes place finds.

In a further modification, this includes the micro generator generating a wave field tion, e.g. a waveguide, at least partially around the container and several in rich direction of the container-facing radiation openings for Mi owns crown waves.

With this solution, the same performance as meet with the above, but here is one  higher profitability to be expected as with a single microwave generator has a higher effect is to be achieved and on the short way around the Containers around practically no in the microwave oven loss to reduce performance is visible.

In a practical embodiment, the container and the generator of the microwave field from surrounded by a metallic shielding cage in which Steam outlet openings are arranged.

This shielding cage has several at the same time beneficial effects. For one, he holds the Mi radiation from humans and animals or plants that are in the vicinity on the other hand it prevents the escape of Microwave energy and thus ensures that the Mi crown wave energy inside the shielding cage is preferably absorbed in the water of the container.

In training of the latter configuration a heat between the container and the shielding cage insulation zone with heat-insulated spacing and loading strengthening agents formed.  

The heat insulation zone ensures that that of the warm water radiated in the container does not heat can immediately transfer to the environment. Rather bil a warming sheath surrounds the container contributes to the absorbed microwave energy instead to compensate for heat losses for steam formation is used.

The shielding cage is preferably in the form of a microwave trained as a reflector.

This measure ensures that the water penetrating microwave radiation not in the shield is absorbed by the cage but one more time the water in the tank is directed and so another absorption can take place. Furthermore this will also cause undesirable heating of the Shielding cage and thus a risk of burns Avoided touch.

The shielding is in one embodiment of the further training cage is double-walled and has an inside outer and outer coat. The steam outlet The outer ends of the openings are more labyrinthine Channels formed that lead from the inside to the outside.  

The double design of the shielding cage an even better shielding of non-absorbed micro wave energy reached. At the same time is also through the further air layer between the shielding cages the heat insulation increases. Because with a single-walled Shielding cage the problem of water vapor outlet opening also escaping microwave beam lungs exists, this undesirable appearance double wall in connection with the Fix the labyrinthine design of the channels. These Channels act for the non-absorbed microwaves radiation as a trap.

In a further development of the invention, the container comprises a water level control device.

This ensures that the microwave energy is always delivered to the same volume of water and thus the evaporation conditions are predictable are. However, it should be emphasized that the water level regulation not such a strict compliance needs a certain level, like one in the water immersed heating element. This is because even if the water level is low, the micro wave energy is absorbed by this volume of water,  but then a higher specific energy supply takes place finds.

The water level control device is preferably through a freshness arranged outside the microwave field water vessel formed of much larger volume. The This fresh water container is connected to the container.

This configuration comes without mechanical control means because the water level is based on the principle of commun decorative tubes is observed. The danger of one Nucleation due to the longer downtime of the water in the fresh water container doesn't matter because also by microwave radiation, and here in more effective than a heating element, a disinfectant effect occurs.

The device is in a variable power range operated, the microwave field is advantageous generating generator in amplitude and / or Pulse-pause ratio adjustable. To this An electrical or electronic control can be used in this way erable, for the microwave generator very gentle Be influence the evaporation performance.  

Further developments and advantageous embodiments of the Invention result from the claims, the description exercise and the drawing, in which several execution examples games are illustrated.

Show it:

Fig. 1 shows a schematic cross section through a first embodiment of the device with a innenlie constricting microwave generator,

Fig. 2 shows a schematic cross section through a second embodiment of the device with a außenlie constricting microwave generator from a plurality of generator units,

Fig. 3 shows a schematic cross section through a third embodiment of the device with a außenlie constricting microwave generator and a microwave line,

Fig. 4 is a schematic cross section through an embodiment of the device before highlighting con structive designs of a multi-part shielding cage with an internal microwave lengenerator, and

Fig. 5 is a schematic cross section through an embodiment of the on device with a double walled shield and a fresh water tank.

The embodiments shown in FIGS. 1-5 egg ner device for generating water vapor have as common features a container 12 filled with water 10 , which is provided with a water vapor outlet opening 14 . The container 12 consists of plastic or a ceramic mass, that is, a material without polar molecular formations. The container 12 is located in a shielding cage 28 for microwaves, which is provided in the upper region with one or more water vapor outlet openings 30 . Between the container 12 and the shielding cage 28 , a heat insulation zone 32 is formed.

In FIGS. 1-3 several embodiments for the arrangement and configuration of a field generating a microwave generator 16 are shown. In Fig. 1, the generator 16 is inside the loading container 14 and has ver on its outer circumference dividing radiation openings 18 for microwaves. In FIGS. 2 and 3, the generator is disposed outside the loading hälters 12th

Fig. 2 shows a proposal with several Ge generator units 20 , the 12 in the direction of the container facing radiation openings 22 for microwaves and Fig. 3 shows an arrangement in which only a micro wave generator 16 is present, but the microwave energy via a microwave line 24 is distributed and emitted via radiation openings 26 . The micro wave line 24 , for example a waveguide, surrounds the loading container 12 almost completely and the radiation openings 26 are each directed towards him.

Fig. 4 shows structural details of the shielding cage 28th In this illustration, the microwave generator 16 is not shown for reasons of clarity. The shielding cage 28 consists of segments, for example in the form of angled metal sheets, which are not integrally connected to one another. They can therefore be easily dismantled for maintenance work. The microwave radiation emerging through the gaps is small compared to the rest of the surface.

With small and medium power this leads to sufficient shielding so that outside the shielding the measurable microwave field remains below the permissible limit values. For spatial fixation and for better insulation of the container 12 in the shielding cage 28 , spacing and fastening means 34 made of heat-insulating material, for example made of plastic, rock wool or ceramic, are provided and the cavities are filled with heat-insulating material.

If the scouring effect of a single-walled shielding cage 28 is not sufficient because of a particularly high output of the microwave generator 16, a double-walled shielding cage can also be made from an inner jacket 36 and an outer jacket 38 , as shown in FIG. 5. In this embodiment, the continuous and interrupted areas of the inner and outer jacket 36 , 38 overlap, so that there is no direct, straight-line connection from the inside to the outside. This applies in particular to channels 40 through which water vapor reaches water vapor outlet openings 30 . The channels 40 and the rest of the space between the jackets 36 and 38 acts as a radiation trap for the microwave rays. The intensity of the microwaves decreases sharply after repeated reflection and the associated absorption.

As a further development of a water level regulation of the water 10 in the container 12 , the embodiment in FIG. 5 shows a fresh water vessel 42 which communicates with the container 12 via a connecting line. Since the volume of the fresh water vessel 42 is significantly larger than that of the container 12 , there is hardly any lowering of the water level even after the evaporation of a considerable amount of water in the container. Since the fresh water vessel 42 is arranged outside the shielding cage 28 , there is no heating of the supply water here.

To operate the device according to the invention, an electromagnetic vibration lying in the microwaves range is generated by means of the microwave generator 16 . The radiation emerging from the outlet openings as a result of this electromagnetic vibration penetrates the surroundings of the microwave generator 16 and forms a microwave field. Substances made of non-polar molecules are penetrated without weakening the microwave radiation. However, if there are substances made of polar molecules, such as water in the microwave field, the molecules are caused to vibrate as a result of the electromagnetic radiation, but energy is absorbed from the microwave field due to the inertia of the molecules. This energy leads to heating of the substance made of polar molecules.

In the device according to the invention, the water 10 present in the container 12 is heated in a targeted manner, while the container 12 is not heated by absorption of the microwave energy. It only heats up via the heat emitted by the water 10 .

In the course of the heating, especially the water molecules located in the surface area of the water 10 easily pass into the vapor state. This event occurs at relatively low temperatures, that is, below the boiling point of the water, so that surprisingly less energy is consumed than was the case with previously known devices.

For the construction of the microwave field, it is in principle irrelevant whether the microwave generator 16 is in the container 12 or outside. However, both configurations have advantages from case to case. Thus, in the embodiment according to FIG. 1, the inevitable heat loss of the microwave generator 16 is also given off directly to the water and contributes to its heating. In addition, the microwave radiation is so strongly absorbed when it passes through the water 10 that only a little external shielding is necessary and the ambient radiation remains below certain limit values.

On the other hand, with the solutions according to FIGS. 2 and 3, a significantly higher microwave energy can be coupled into the water 10 , since the outer surface is larger and the volume available for the microwave generator 16 is larger.

The energy that is not absorbed by the water 10 when the microwave radiation passes through the first time is not lost in the embodiments presented. Rather, the rays are reflected by reflection on the walls of the shielding cage 28 and are thus returned to the water. For this purpose, the shielding cage 28 is simultaneously designed as a reflector, which is achieved by using highly conductive materials with a smooth surface. The portion of microwave energy absorbed in the shielding cage 28 can thus be kept low.

The air located between the container 12 and the shielding cage 28 forms a heat insulation zone 32 which prevents heat from the container 12 from being dissipated directly to the surroundings and deteriorates the efficiency. In the embodiment of FIG. 5, the heat insulation is further improved by using the second outer jacket 38.

The embodiment according to FIG. 4 shows a modification of an arrangement of the microwave generator 16 in a central recess of the container 12 , which is accessible from below. As a result, the microwave generator 16 , which is not in the water 10 here, can be easily replaced or maintained.

The intensity of the microwave field can be Adjust the steam requirement accordingly by the Amplitude of electromagnetic vibrations or Pulse-pause ratio is changed.

The device works silently because there is no space  air circulation or atomization takes place and also no strong boiling phenomena occur, as they do when heating with heating elements are known. Especially Another highlight is the sterilizing effect. Because the water molecules in the germs are flat if exposed to the microwave field, the direct heating of these polar molecules to a ver Change in the molecular structure and thus a killing germination.

Lime deposits also impair the function not because it supplies energy to the water molecules don't stand in the way. In the event of lime failure and on there is no hard incrustation of their salts, because there are no concrete crystallization nuclei, such as represents a known heating element. So the performance of the device remains above lan constant over time, which is also beneficial for the war intervals. The maintenance work itself are easy because of the presence of lime can be easily removed.

Claims (14)

1. Apparatus for generating water vapor, in particular for air humidification, consisting of a container ( 12 ) filled with water ( 10 ) which is provided with water vapor outlet openings ( 14 ) and in which the water ( 10 ) is supplied with thermal energy since characterized in that the container ( 12 ) is at least partially with the water ( 10 ) in a microwave field generated by a micro wave generator ( 16 ) angeord net. 2. Device according to claim 1, characterized in that the container ( 12 ) consists of a non-metallic, non-polar material, preferably made of plastic, glass or ceramic. 3. Apparatus according to claim 1 or 2, characterized in that the generator ( 16 ) generating the microwave field is arranged inside the container ( 12 ) consisting of a material shielding the microwave radiation. 4. The device according to claim 3, characterized in that the generator generating the microwave field generator ( 16 ) pointing in different directions from beam openings ( 18 ) for microwaves. 5. Apparatus according to claim 1 or 2, characterized in that the generator ( 16 ) generating the microwave field is arranged outside the container ( 12 ). 6. The device according to claim 5, characterized in that the generator generating the microwave field generator ( 16 ) in a plurality of generator units ( 20 ) is arranged divided among the containers ( 12 ) and each generator unit ( 20 ) has radiation openings ( 22 ) for microwaves has, which point in the direction of the container ( 12 ). 7. The device according to claim 5, characterized in that the generator generating the microwave field generator ( 16 ) comprises a microwave line ( 24 ), for example a waveguide, which is guided around the container ( 12 ) at least partially and several in Rich direction of the container ( 12 ) facing radiation openings ( 26 ) for microwaves. 8. Device according to one of the preceding claims 1-7, characterized in that the container ter ( 12 ) and the generator generating the microwave field generator ( 16 ) are surrounded by a metallic shielding cage ( 28 ) in which water vapor outlet openings ( 30 ) are arranged . 9. The device according to claim 8, characterized in that between the container ( 12 ) and from the screen cage ( 28 ), a heat insulation zone ( 32 ) with heat-insulating spacing and fastening means ( 34 ) is formed. 10. The device according to claim 8 or 9, characterized in that the shielding cage ( 28 ) is designed as a micro wave reflector. 11. Device according to one of claims 8-10, characterized in that the shielding cage ( 28 ) is double-walled from an inner ( 36 ) and an outer jacket ( 38 ) and that the water vapor outlet openings ( 30 ) the outer ends of a labyrinthine form channels ( 40 ) leading from the inside to the outside. 12. Device according to one of claims 1-11, characterized in that the container ( 12 ) comprises a water level control device ( 42 ). 13. The apparatus according to claim 12, characterized in that the water level control device ( 42 ) by a fresh water vessel ( 42 ) is formed much larger volume than that of the container ( 12 ), which is arranged outside the microwave field. 14. Device according to one of claims 1-13, characterized in that the generator ( 16 ) generating the microwave field is adjustable in amplitude and / or in the pulse-pause ratio.