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Title:
DEVICE FOR TRANSMITTING HEAT AND MATERIAL BETWEEN LIQUID AND GAS
Document Type and Number:
WIPO Patent Application WO/2001/016546
Kind Code:
A1
Abstract:
A device for heat and mass exchange between a gas and a liquid is equipped with a downwardly pointing spread-blade and a structure for even distribution of liquid onto a section of the spread-blade's width. The device comprises: an element (2) fixed at opposite edges of the spread-blade and pointing downwards, and an initiating structure for directing the liquid towards the stretching elements (2). The stretched liquid film (1) forming a generally vertical liquid curtain of plane shape is contacted by the gas on both sides. Several liquid films (1) can be advantageously arranged in parallel. The liquid film (1) can be permanently maintained after being initiated.

Inventors:
Czintos, Csongor (Csáky u. 3, Kecskemét, H-6000, HU)
Application Number:
PCT/HU2000/000093
Publication Date:
March 08, 2001
Filing Date:
August 28, 2000
Export Citation:
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Assignee:
Czintos, Csongor (Csáky u. 3, Kecskemét, H-6000, HU)
International Classes:
F28F25/04; (IPC1-7): F28F25/02; F24F6/04
Foreign References:
US4372897A
US5226935A
US4980098A
DE2534524A1
US44119301A
US4980098A
Attorney, Agent or Firm:
DANUBIA PATENT AND TRADEMARK ATTORNEYS (Bajcsy-Zsilinszky út 16, Budapest, H-1051, HU)
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Claims:
CLAIMS
1. Device for the transmission of heat and material between gas and liquid equipped with a downward pointing spreadblade and a structure to conduct evenly the liquid onto a section of the spreadblade's width, with the characteristic that it has a longitudinal stretching element at the two extremities of the referred section to stretch the edges of the liquid film formed from the liquid streaming down on the referred section of the sheet, with the stretching elements pointing downward, to initiating structures for spreading downwards the liquid film along the stretching elements, which conduct supplementary liquid onto the stretching element.
2. The device as claimed in claim 1 characterized in that the stretching elements converge downwards.
3. The device as claimed in claim 1 or 2 characterized in that the structure conducting the liquid onto the spreading element is equipped with a basin or tray with an open liquid level having a weir crest and the spreadblade is connected to the weir crest.
4. The device as claimed in claim 3 characterized in that the structure conducting the liquid onto the spreadblade is equipped with guiding elements arranged in the basin or tray, to make the flow of the liquid even, which are basically in a parallel position to the weir crest.
5. The device as claimed in any of claims 14 characterized in that the initiating structure comprises of the section of the stretching element laid on the spreadblade. within which the stretching elements converge.
6. The device as claimed in claim 3 or 4 characterized in that the initiating structure comprises of the holes or depressions made on the wire crest, connected to the section of the stretching element laid on the spreadblade.
7. The device as claimed in any of claims 16 characterized in that the lower extremity of the stretching elements is located in a respectable and that an additional spreadblade and two stretching elements are connected to the receptacle.
Description:
Title Device for Transmitting Heat and Material Between Liquid and Gas Technical Field The subject of the invention is a device for the transmission of heat and material between liquids and gases or more precisely, a stretched liquid film humid heat exchanger, that is, a device aiding the transmission of heat and material at the boundary layer (surface) of liquids and gases, with the aid of a substrate-free stretched liquid film created in the gas space, which can be cascade connected onto each-other (in tandem). The device contains a downward pointing spread-blade and a structure conducting the liquid evenly onto a section of the blade's width.

Such a liquid film or liquid lamella-type transmitter if multiplied, can be set-up as rows of lamellas or multi-lamella transmitters.

Background Art A task emerging frequently in the different areas of engineering is to make heat and material transmission more intensive between liquids and gases. Depending on the task and the primary medium, this could be heating, cooling, introduction of gas, degasification, ventilation, evaporation or condensation. It is a well known fact that the characteristic processes taking place in the course of the transmission of heat and material are very similar, so much so that should we refrain form conscientiously blocking one of the processes, several and multi-directional processes could take place simultaneously.

Different solutions have been developed to increase transmission in the numerous areas of use. The aim of the majority of these solutions was to increase the surface area as the most obvious method, but a number of solutions either conscientiously or through experience improved the heat or material transmission factor.

The heat and material transmission processes between liquids and gases have enormous significance in almost all areas of environment protection, in the most important areas of heat energetic as well as in a number of areas in the chemical and food industry, and thus the improvement their efficiency is a very important task. Better and more efficient solutions will bring

us closer to the better protection of the environment and to the conservation of its original state.

US 44119301 describes a solution with an downward pointing spread- blade associated to an structure conducting liquid onto it, which takes the liquid evenly onto a section of the blade's width. The evenly distributed liquid falls off the edge of the blade in free fall and for a time it falls in the form of a liquid film.

In the absence of guiding, the edges of the liquid film are shaped freely by the effect of surface tension and gravitation. As a natural consequence of the surface tension, the liquid tries to take-up a circular cross-section. For this reason the width of the liquid film will decrease in a very short distance, while the thickness of the liquid film increases. Therefore this known solution is not effective. In the absence of guiding, the liquid film becomes unstable as a consequence of the smallest airflow, and especially the condition of the lower edge is uncertain, and therefore in order to set-up several liquid films in parallel, side-by-side, created with the aid of spread-blade it is necessary to make the distance between the films relatively big, resulting in a poor utilisation of space.

US 4980098 describes the use rod shaped elements onto which liquid is poured through a gap. The rod shaped elements are placed very near each other in a close-set manner and a liquid film could accidentally form between them (under certain flow conditions). The close-set spacing is necessary because to total surface of the strands must be sufficiently big. In the case of the liquid film in the solution referred to, turbulent flow cannot form due to the relative nearness of the rod shaped elements, since the adherence to the surface slows the liquid down to such an extent that the formation of turbulence can be completely excluded.

A clear disadvantage of this solution is the per chance nature of liquid film formation, the impossibility of regulating it and its uncertainty. An other disadvantage is the"utilisation"of both sides of the strands for film forming, as the experiences show that in such cases the film on the one side or on the other side pulls away the other in a random variation turning the forming and sustaining of the liquid film chancy. This can only be prevented if the volume of the liquid poured onto the strands is as much as required to fill up all

intermediate spaces, but in such cases a large amount of excess liquid incapable of participating in the transmission process flows away, impairing significantly efficiency.

The stabilisation of the film-state, the stretching of the film to the largest possible surface and the determination of the angle of incidence of the strands is not included in the subject of the patent referred to above.

General Disclosure of the Invention The object of invention is to develop a device operating with better efficiency by reducing the disadvantages of the solutions referred to above.

A further aim of the invention is to improve he space utilisation of the device.

We have achieved the objectives set forth with a new type of device in comparison to the earlier solutions.

The task to be solved with the aid of the invention is the creation of a larger surface, more stable liquid film using la smaller amount of liquid.

We have solved the task in accordance with the invention, with the development of a device suitable to carry out heat and material transmission between liquid and gas, with the device having a downward pointing spread- blade and an structure conducting liquid evenly onto a section of the blade's width. According to the invention the device also includes a longitudinal stretching element located at the extremities of the referred section of the spread-blade, rod or strand, to stretch the edges of the liquid film made by liquid streaming downwards, with the stretching elements pointing downwards, two initiating structures for extending the liquid film downwards along the stretching elements, conducting additional liquid onto the stretching element.

According to the invention a new effect is introduced relative to the solution applied by patent US 4980098, since as a result of placing the strands at an angle and sufficiently far from each-other, and of the auto-threading system, the liquid film stretches and the flow in the interior of the film turns from linear to turbulent (or possibly transient), causing a significant increase of the heat and material transmission. (This is substantiated by our measurement results too.)

The invention stretches the ad-hoc moving, labile, approximately triangular shaped liquid screen of the solution offered by patent US 44119301 onto a liquid film of almost double geometric surface and less then half thickness, having a multiple transmission coefficient from the aspect of transmission. If stretching is not applied, the essential feature is lost.

The very complicated liquid distribution system in patent US 44119301 becomes superfluous, because the stretched film, according to the invention, evens up and distributes the inhomogenities of the supplie water in a far broader interval than that referred to.

In case of a preferred form of implementation the stretching elements converge downwards.

The structure conducting the liquid onto the spread-bled can have: -a basin or tray containing liquid with a free level, with a weir-crest, and the spread-blade is connected to the weir-crest.

The structure conducting the liquid onto the spread-blade should have a guide in the basin or tray to even out the flow of the liquid, and the guide and the weir-crest should be in a parallel position.

The section of the stretching element laid on the spread-blade within which the stretching elements converge could form the initiating structure.

A hole or dent made on the weir-crest and connected to the section of stretching element laid on the spread-blade could also form the initiating structure.

For an especially advantageous implementation the lower end of the stretching elements are located in the receptacle with an additional spread- blade and two stretching elements connected to the receptacle. With this solution it is possible to make a device containing several superposed liquid films arranged in cascade.

The device, according to the invention, for aiding the transmission of heat and material at the interfacing surface of liquids and gases in any direction, contains approximately plane, substrate free liquid film-sheet rows contacting with the gas on both surfaces, made in the free-flow or forced flow gas and placed in parallel to each-other and the direction of the gas flow, in a perpendicular and close-set arrangement, where heat and material pass

simultaneously from one medium into the other through the phase boundary surface of the liquid lamellas.

The liquid with an adequate flow volume is conducted into an exactly horizontal tray made of corrosion resistant steel or UV stabilised plastic, open on the top, having a weir-crest and if necessary, equipped with guide element and guide wall on the inner side in such a manner, that the inlet of the liquid causes the least possible of disturbing waves or flows; after the tray is filled the liquid drops over the weir-crest and forms a practically free-falling, continuous and stable liquid film.

The tray is equipped with a pair of stretching rods or strands made of the same material as the tray or some other suitable material, set either at an angle depending from the viscosity and surface tension and the flow characteristics of the gas of the liquid, or self-setting, capable of limited flexible movement if required, which serves the purpose of auto-stretching the liquid film, and the rods are located at the outlet plane of the weir-crest, at the edges of the liquid film-sheet section. The preferred cross-section of the rods or strands is circle or polygon.

For automatically initiating the formation of the liquid film an initiating structure is provided, which ensures that the water begins streaming through a slot 43 onto the rod 32, said slot is formed in the weir crest at its extreme end above the rod 32. thereby forming of the liquid film is initiated as it were drawn between the pair of rods 32, then the film is kept stretched by the rods 32 by the surplus quantity of water flowing through the slots 43 and trickling down the rods 32, thereby also providing additional water supply for the free-falling liquid film getting thinner and thinner due to its growing velocity and causing thereby lengthening the path until the water falls into drops.

The downward flow of the liquid already spilled over is guided at the edge of the weir crest section over the rod 32 by the structure ensuring the automatic threading of the liquid film which forms part of the tray, with the aid of a stop, conducting the liquid starting at the edge of the weir crest towards the interior of the film, thereby also providing additional water supply for the free- falling liquid film getting thinner and thinner due to its growing velocity and causing thereby lengthening the path until the water falls into drops.

The material of the weir-crest should withstand eventual abrasion, mechanical, physical (e. g. radiation) and chemical actions, and in the event of biologic uses microbes should not be able to adhere to it.

The egressing edge of the weir crest should preferably be knife-like sharp to prevent the back-flow of the liquid that would disturb the formation of liquid film or result in the formation of sediments.

The operation of the device can be enhanced by the use of additives.

The liquid onto which additive has been mixed can withstand surface tensions several orders of magnitude higher than that of the primary liquid without degrading the heat and material transmission coefficient in respect of the primary medium.

The device can create the liquid film in the form of sectional units, making thereby possible the splitting of the gas flow in order to prevent the creation of a stable laminar flow.

The bottom of the liquid film must not be allowed to break freely into drops. Therefore the difference in the height of the upper and lower basins depending on the viscosity and temperature, should be determined in such a manner that the liquid film sheet be set-up in the interior of the basin, and so the noise (gurgle) generated by the droplets and the unnecessary eddying can be prevented.

Short description of the drawinqs The invention will be described in detail on the basis of the exemplary embodiments shown in the attached drawings. In the drawings : Figure 1 shows a schematic design of a single unit version of the device, according to the invention for transmitting heat and material between liquids and gases, Figure 2 shows a front-view of the tray of the device shown in figure 1 with connected stretching elements and two types of initiating structures, Figure 3 is a side-view of figure 2, Figure 4 is a sectioned view showing three versions of a lower part at the bottom edge of the weir crest of figure 3 in an enlarged scale,

Figure 5 shows a side-view of a room vaporiser set up on the basis of the version shown on figure 1 and mounted behind a heater, Figure 6 shows a schematic view of the room vaporiser of figure 5 complemented with a blower wall-side and intended to be mounted next to a wall, Figure 7 shows the internal structure of a counterflow, multi-lamella transmitter built into the air-channel, made up from cascade units placed side-by-side and in file, with symbolic casing, Figure 8 shows the schematic site design of a unit with cascade arrangement suitable to form two liquid lamellas, Figure 9 shows the side-view of a cross-flow multi-lamella transmitter, viewed from the end of the trays used to create the liquid lamellas, Figure 10 is the front-view cut of the multi-lamella transmitter shown on figure 9, Figure 11 shows the site view of an enlarged part of the multi-lamella transmitter shown in figure 9.

Detailed description of the preferred implementation forms Figure 1 shows the preparation of the liquid film in accordance with the invention. The structure of the device required to prepare the stretched liquid film 1 is the following : The incoming liquid 18 is conducted into a tray 3. When the tray 3 is filled-up the liquid spills over the horizontal weir crest 6, arriving in a free-fall into the lower receptacle 22 in the form of liquid film 1. Initially the weir crest 6 is bowed, with a radius of 1-10 cm; the liquid which leaves the tray 3 with a lateral velocity vector adhering to the bow turns it to almost vertical direction, and its lower part acts as a spreading blade ensuring the even drainage of the liquid. There are stretching strands 2 at the two extremes of the weir-crest 6 positioned in an arrangement suitable to ensure that the liquid film is stretched to the maximum, physically possible stable size. The two strands are not necessarily vertical, they are positioned to converge from the theoretic vertical direction 8 towards the interior of the liquid film 1 with a convergence angle between 0-10 degrees. The lower end of the stretching strands are mechanically set or weighted down in the required position. The liquid arrives to

the bottom of the weir crest through an automatic drawing system as shown in figure 2 thereby ensuring the automatic redrawing after a stoppage or at the initiation. The distance and angle of the stretching strands 2 and the maximum height of the liquid film depend on the liquid, its viscosity and surface tension, and the value can be calculated in an exact manner. In the case of water-air the optimal distance is 25-50cm, the convergence angle is 3-10 degrees, and then the maximum film height is 60-90cm, depending on the temperature and the velocity of the air flow. Over these values, as a result of the free-fall, the velocities in the interior of the film are so high that the film is torn. Knowing the concrete pair of media in question, the difference in height between the lower basin 22 and the water level 27 of the tray 3 should be adjusted in a manner that avoids the rupture of the film prior to its arriving into the lower basin 22.

The stretching strands 2 can be of a monolithic form, as in our case, from metal or plastic material, e. g. PVC, but the optimal material to be used must be selected on a case by case basis.

The stretching strand can be made from spinned fibres or fibres fit together in some other manner, it can be rigid or flexible, rod or rod like. The selection depends on the media, the velocity of the gas flow and the evenness of the flow.

The cross-section of the stretching strand can be a circle, polygon, open or closed profile, or can be made by spinning. The characteristic diameter is 1- 8 mm.

The upper end 2a of the stretching strand 2 should be formed to allow fastening. Fastening should preferably be done by either biting or clamping the thickened end 2a of the stretching strand 2 into a bore 48 made onto an end- plate 5 of the tray 3. The cooled down water arriving into the lower basin should either be recycled (pump 11, piping 23) or drained to the next process step 19in question.

The steady, even flow of the water is provided by at least one guide 4a built into the tray 3 ; the same could be achieved by the adequate arrangement of the tray 3.

The upper bowed section 6of the weir crest 6 conducts the liquid smoothly onto the lower, vertical section, which is a plane sheet with a thin, 0.1-

0.5 mm blade like bottom edge thereby ensuring that the adhering liquid deviate the film from the vertical position as little as possible. (A number of patents discuss in detail the correct arrangement of the weir crest, although the edge arrangement is not protected by patent).

Room air vaporisation equipment is one of the most characteristic non industrial utilisation.

The pump 11 pumps the water to be evaporated, poured into the lower basin 22 onto the upper tray 3 through the pipe 23. Once the tray 3 is filled, the water spills over the weir crest 6 and forms a liquid film 1 while free falling between the stretching strands 2. The cycle is closed at the lower end of the film flowing back into the lower basin 22. The evaporated water is replaced through the refilling hole 47. A blower 45 could be built in to provide a more intensive evaporation of the water, which moves, preferably sucks the air, in parallel with the plane of the liquid film. Water level sensor 46 ensures the minimal water level thereby preventing the dry running of the pump. (The water level sensor 46 could also be connected to a float-valve thereby ensuring automatic replenishment). The horizontal position of the device can be adjusted with the aid of adjusting bolts in the manner shown in figures 5 and 6.

Figure 2 auto-threading system.

The liquid gets to the weir crest 6 from the tray 3 through an auto- threading system then falls freely. The purpose of the auto-threading system is to get additional liquid to the edge of the liquid film 1 on the edge of the weir crest 6 (onto the stretching strands 2), thereby ensuring that the liquid starting to spill over at the lower end of the weir crest 6 sprinkles down every time (and not by chance) first at the edge of the weir crest 6, thereby initiating the formation of the liquid film 1. With the intensification of the spill-over the liquid film triangle formed between the lower edge of the 6 weir crest and the stretching strands 2 will grow until the triangles drawn in the two sides come together and clamp giving a final form to the liquid film 1. An other task of the additional liquid conducted onto the stretching strands 2 is to provide replenishment for the film which would break-off thereby maximising its strainability.

The figure shows two solutions : a hole is formed on the left extrem of the weir crest to ensure supplementary liquid, or the same purpose could be achieved by directing the stretching strands more towards the centre. The hole should have a cross section 1.5-4 times the square of the initial liquid film thickness. For the solution shown on the right side, the skewness to approach the other stretching strand should be set to ensure that the additional water getting initially onto the stretching strand should be 1.5-4 times the square of the initial liquid film thickness! In our case the stretching strand is made of solid material, its end 2a is fastened onto the bore 48 formed on the en-plate 5 of the tray 3, its section 2b snugs up to the weir crest 6 following its shape, and, viewing from the front, deflects the liquid at a Gamma angle guiding it towards the centre of the weir crest 6.

The stretched liquid film created with the aid of the stretching strands is stable, breaking only in case of very strong air flows, but even then, it returns to the original, desired state due to the auto-threading system.

Figure 3 Canting of the liquid film Although the plane of the film will become tilted (at a Delta angle) with the canting of the stretching strands, but the surface will increasingly approach the perfect plane. Whether this is necessary and to what extent, should be determined knowing the media-pair and the conditions of the task..

Figure 4 Forming the edge of the weir crest. The weir crest can be straight as at 6a, blade-like as at 6b or slightly bent back as at 6c, having thereby the initial angle of the liquid film (the angle between the velocity vector at the moment of leaving the lower edge of the weir crest and the vertical) point slightly (0-20 degrees) forward, thereby minimising the bending back of the film.

The canting of the theoretic middle surface of the liquid film is closely connected with the canting of the stretching strands (Figure 3).

Figures 5. and 6. shows the placing of a room air humidifier behind a radiator The figure shows the device in a version suitable to be mounted between the wall and the radiator.

The minimum space required is 70 mm which is available in case the radiators are mounted in a regular manner.

The replenishment of the water evaporated from the device can be safely and comfortably accomplished from the side.

The special advantage of the arrangement is that the air warmed-up by the radiator flows upward causing intensive evaporation. The circulation is ensured, since the air of the room needs to be humidified only during the period of heating.

The device is fixed behind the radiator 38 with the aid of a suspension girder 50, longer than the horizontal length of the device, which sits on the radiator clips 52, and also suspends the device 10 through the two adjusting screws 36 with the help of the nuts 51.

The radiator clips are sure to stand the weight of the device as its weight even when filled up must not exceed 8 kgs.

For the arrangement described above it is not necessary to build in a supplemental blower because the radiator heats at the time of the device's operation providing the necessary gravitational air circulation.

Figure 7 shows the site view of a counterfiow humid heat-exchanger block This device is essentially different from those described above ; with its help it is possible to make the liquid and gas counterflow in a quasi-parallel direction. In order to accomplish this it is necessary to place air baffles 37 in the space between the liquid lamellas-segments set beside each-other with the appropriate lateral distance (and also in the space between the external casing 25 of the transmitter). Their function is to guide the gas flow into the proper direction. The air baffles 37 are positioned in such a manner that allows the gas to flow characteristically along the streamline 28 thereby forcing the air to pass through the liquid lamellas. The number of liquid lamella segments is not limited.

8. Connecting stretched liquid films in series If the 1 stretched liquid film is not conducted into the basin 22, but into a characteristically identical tray 3, the film formation is then continued in an

identical manner to the formation of the first film, and the films are connected in series.

The positioning of the trays in respect of each-other is naturally determined by the task.

The stretching strand should preferably made of rigid material in the following manner: The strand is made of solid matter, its middle section 2c is bent with the purpose of positioning the strand accurately at the arrival to the lower tray. The two straight legs of the strand 2 are bent upwards in an angle corresponding to 90 degrees minus beta, and then offsetting section 2d at an angle gamma to the perpendicular, guiding thereby the water streaming down on it towards the interior of the film. The guiding starts at the section 2b of the stretching strand. Section 2b fits to the curved surface of the weir crest 6, section 2d to the surface of the straight part of the weir crest 6 thereby preventing the water from flowing under it.

The lower extreme of the stretching strand 2 is not fastened, as it is located below the water level in the tray located below, and movement in any direction can only occur to the effect of significant forces.

The arrangement of the lead string as shown in figure 2 ensures the automatic threading of the liquid film, that is, the self induced formation of the film after occasional breaks or at the start of the process.

Figures 9 and 10 Cross-section of purely cross-flow multi-lameila transmitter.

The figure shows the cross sections of a purely cross-flow humid heat exchanger, mountable in the air channel. The flow of the liquid is four staged, five rows of planes are placed in parallel, and 2x24 stretched films are installe in tandem.

The air flow is practically parallel to the liquid lamellas, having a speed of 0,5-3m/sec passing through an inlet tube 12, a 13 diffuser, forming the heat exchanger itself, a confuser 17 and through an outlet piping 16.

Trays 3 are fixed to a tray support frame 7 in the arrangement shown in figures 7 or 9 and 10. The ease of mounting and dismounting, replacement, the unchanged position of the remaining trays during replacement and the

replacement being positioned in the exact same place and manner are important aspects in the arrangement.

The installation of the tray support frames 7 with an accuracy of 0.1 mm corresponds to the normal manufacturing accuracy. It is not necessary to provide separately for the horizontal positioning of the trays, since the horizontal positioning of the complete heat exchange unit is a simple engineering task.

The liquid 18 to be cooled (water) is poured into an upper distribution basin 21, where an overflow 20 ensures the quasi identical level of the liquid.

At the bottom of the basin 21 there are holes 34 formed as shown in figure 11, through which a precisely determined volume of liquid flows into the upper row of trays, and spilling over the weir crest with 6 a damped flow as shown and detailed in figure 1, forms a liquid film 1. The lower part of the liquid film 1 gets into the tray placed below it and the cycle starts anew. The cycle starts as many times as the number of tray rows above each-other (four in our case). The tray rows are placed behind each-other at a distance permitting the flow of the cooling air, in our case 1-10 cm. The ideal distance depends on the velocity of the gas flow, the angle of entry, the flow volume of water, the surface tension, viscosity temperature and pollution of the participating media.

From the lowermost tray the liquid still in a stretched form gets into a lower receptacle 22 exiting it by way of a tube 19. If required however, there are regulating fixtures 24 and a recirculating pump 11 to recirculate the liquid.

Then the liquid is taken into the upper basin 21 for further cooling. This recirculation may be necessary for instance in the case of gas washing or evaporation, when not only the heat contents of the liquid needs to be changed.

The gas 28 flow streamlines in the device shown in figures 9 and 10 are almost horizontal, with an even distribution.

The liquid lamella groups placed side by side and below each-other are called liquid lamella segments. By placing several lamella segments behind each-other (in tandem) the transmitter can be made multi-staged on the gas side too, in the case of these figures they are five staged. The determination of the distance between the segments is a task of dimensioning, the figure shows

immediate closeness, whit the trays directly connected to both sides of the tray support frame 7.

The turbulent flow of the gas is ensured by the stretching strand 2 at the front en of the lamellas, the gap between the liquid films 1 and the penetrability of the small air channels.

The velocity of the gas flow in the heat exchanger determines the maximum height of the liquid film 1. The velocity of the air cross-flow arriving at an angle not larger than 10 degrees relative to the plane of the film for water-air pair has been found empirically to be about 0.5-3. m/sec.

Figure 11. Conduction of water into the uppermost tray The operation of the multi-lamellas transmitter demands that the liquid pass over the weir crest 6 as smoothly as possible. Therefore it is practical to use flow guides, or to arrange the tray in the manner shown in figure 1 in order to force the flow onto a constrained path where the direction of the waves, crosswise relative to the longitudinal axis of the tray, can be turned to longitudinal.

Furthermore, the even and continuous distribution of the liquid between the numerous tray rows necessary in the case of larger devices must also be solved.

The 18 in-flowing liquid arriving at the basin 21 swells up to the level 27, thereby ensuring precisely the proper and desirable pressure at the bottom 35 of the basin. The liquid streams down through gaps 34 and wire crest 33 onto a support sheet 32. The support sheets 32 bite the bottom of the basin in a self- locking manner with the aid of the fangs 31. The lower edge of the support sheet 32 is fully immersed in the water of the tray 3 to ensure that the water streaming down arrives into the tray without swashing. The transversal and longitudinal dimensioning of the gap 34 ensure that the water streaming down are of the exact volume required for the formation of the film.

The gap 34 can be replaced by suitably dimensioned bores too.

The liquid input can also be solved in other ways.

Example: Description of the device utilisable with cooling towers. (see figures 9 and 10).

The air channel elements showing in the figures are naturally not necessary in this case.

The prospective parameters of the heat exchanger required in a cooling tower: 10 storeys or levels, 5-15 film lamella segments behind each-other (in tandem).

The gap between the different sections provides for the free or forced vertical flow of the air without having to cover to long horizontal distance in the plane of the liquid film 3. Thereby mixing is ensured while the gas-side laminar flow is prevented.

The trays are placed as high up from the water level of the basin as necessary to ensure the optimal surface of the formed stable liquid film lamella 1. This should preferably be a height of 40-100 cm and a width of 25-45 cm.

The liquid film 3 should clearly form the largest possible continuous surface thereby ensuring the longest possible sustainement of the film phase and the best possible distension of the film.

The ventilating air flows freely or in other occasions in a forced flow between the lamellas 1 located usualiy in pairs directly behind each-other and contacts both surfaces (internal and external) of the liquid film 1. The velocity of the ventilation air should be maintained at 0.1-3 m/sec to avoid disrupting the continuity of the film, blowing the film away.

The tray 3 should preferably be made of stainless steel or plastic, and its suspension alone or in groups ensures a perfectly horizontal rim-line.

The distance between the trays should be chosen to avoid contact between the lamellas 1 even at a maximum wind pressure as this would disrupt the formation of the liquid film 1, or would break the film already formed. The distance. between trays should preferably be 1-50cm. The width of the trays 3 should be about 1-1 Ocm.

In order to improve efficiency, the units of the multi-lamellas transmitter can be connected in series or in parallel. Storeys can be formed from the rows of trays 3 placed side-by-side as shown in figures 7,9 and 10 in such a manner that the liquid film 1 always arrive in the tray 3 located below it. The most even possible flow of the liquid is an important aspect when shaping the trays, as

large turbulence passing through the weir crest would disturb the formation of lamellas.

In practical use, in power plants, 10-15 lamellas can be placed above each-other (on say 10-15 levels), and as a result, the liquid temperature differential can be as much as 10-18 °C.

Description of a device for use in the chemical industry.

Mixing heat exchangers are used in many places at the chemical industry. These devices are used to provide heat and material transmission between liquids and gases in counterflow or cross flow. The efficiency of this process can be significantly improved with the use of our invention.

The precondition for use in the chemical industry: the material should not react with any of the components of any of the media, the temperature should not be close to the solidification point or freezing point, and there should not be materials prone to precipitation or polluting particles or material.

The use is practical because of the simplicity of assembling the tray and the speed of handling.

The advantages of using multi-lamella transmitter : 1.-waste water purification (figures 7,9 and 10) The above figures show the device suitable for the purification of waste water partially only. A significant difference is that the trays must be far more robust and coarse, and when selecting the material of the trays it is important to select plastic material to which the live sludge does not cling and is not given to becoming oily.

No special manufacturing technology is required. All components are made of standard material (preferably corrosion resistant steel or plastic), The oxygen dissolving capacity is excellent The invention, from the aspect of environment protection reduces the noise emission of the sewerage plant to almost zero, as neither the high noise level of the compressors nor the sputtering of the surface aerators appear.

The so colled hydraulic resistance, the"source of loss", the operating loss resulting from the pump's coefficient of efficiency and the resistance of the very short tube section can be kept at a minimum through the architecture of the device.

The loss heat of the pump is fully used to heat the waste water replacing at least in part the surface evaporation loss. (This very same loss heat in the case of the deep aerators exits primarily into the air-space of the compressor house, and secondarily onto the surrounding pure air along the aerials as net loss).

It can be installed in the desired size and configuration, preferably as several smaller units connected individually.

This solution does not require deep aerator basin (as opposed to the 5.5-6.5 m effective depth required by the current most sophisticated deep aerator systems a depth of only 1.5-2.5 m is sufficient). The basin depth actually required needs to be determined taking into consideration other aspects of the sewerage technology in the course of the complex planning.

The investment cost of the sewerage plant can be significantly reduced, as the compressor, compressor house, air-preparation, air supply system, deep

and large size aerator basin and the connected water insulation problems, etc. need not be considered.

Ease of maintenance : Excellent regulating capability. (See above) Partly due to the possibility of stopping and sectioning at will, and partly with the regulation of the pump.

Small structural weight thereby allowing the construction of mobile devices easy to install. During maintenance cranes might not be needed to remove the trays, the suitably dimensioned devices can be moved with human power.

An operational advantage of the device is that the multi-lamella aerator is fully above the surface of the waste water and thus eventual failures area easily detectable.

The device can be installed into the majority of the waste water purification systems operating today without any limits and major modifications.

As a result of its operating principle, the transmission processes are not limited to the envisaged oxygen input but significant cooling and evaporation take place simultaneously, which although degrade the operation of the sewerage plant in winter, in summer however the heat removed from the waste water for evaporation increases significantly the oxygen adsorbing capacity of the waste water. At times it is necessary to remove obnoxious gases from the waste water, and this process too takes place simultaneously.

Mobile systems can be installed anywhere at any time the only requirement being the availability of power supply (e. g. in aerated sand and grease traps in waste water pre-aerator systems, aerated piping, structure for the distribution of re-circulated sludge, in aerobe sludge stabilisation, aerated post-purification lakes).

In the case of new installations the plant can be so planned that the residual pressure of the arriving waste water would be sufficient for getting the waste water to the aerating trays.

2.-Water purification (figures 9 and 10) The device to be used in the purification of water is identical to that shown in figures 9 and 10 both in principle and arrangement. No special manufacturing technology is required. All components are made of standard tubes (corrosion resistant steel). All components are stationary (except for the bladed wheel) thus operational abrasion, failure cannot occur.

The coefficient of efficiency is excellent. The device can be installed in any size and configuration.

The ventilation area can be reduced saving thereby significant investment costs. There is no need for technology buildings with high foundation engineering costs.

Ease of maintenance: the trays and lamellas can be adjusted, replaced and cleaned while the others are operating and the dismounting, cleaning and replacement of the different elements can be accomplished in a very short time too.

The device can reduce the technologic times as the better oxygen introduction achieved by it accelerates the biologic-chemical processes.

Excellent regulating capability. (See above) Partly due to the possibility of stopping and sectioning at will, and partly with the regulation of the pump.

Small structural weight thereby allowing the construction of mobile devices easy to install. During maintenance cranes might not be needed to remove the trays, the suitably dimensioned devices can be moved with human power.

An operational advantage of the device is that the stretched liquid film is fully above the surface of the water and thus eventual failures area easily detectable.

As a result of its operating principle, the material transmission processes are not limited to the envisaged oxygen input but significant evaporation take place simultaneously, which although is not favourable in winter, especially in case of surface water taking, in summer however the cooling increases significantly the oxygen adsorbing capacity of the waste water.

Figure 3. Thermal water degasifications (see figures. 9 and 10) The device can be installed in any size and configuration.

Ease of maintenance : the trays and lamellas can be adjusted, replaced and cleaned while the others are operating and the dismounting, cleaning and replacement of the different elements can be accomplished in a very short time too.

There is no danger of clogging.

Small structural weight thereby allowing the construction of mobile devices easy to install. During maintenance cranes might not be needed to remove the trays, the suitably dimensioned devices can be moved with human power.

As a result of its operating principle, the material transmission processes are not limited to the envisaged oxygen input but significant evaporation and convective heat exchange take place too, which aids significantly the cooling of the thermal waters.

4.-Improvement of the oxygen supply of rivers and open waters.

Does not require special manufacturing technology. All components are made of standard material, are robust and simple, thereby eliminating the danger of damages during eventual reconstruction or lifting-out.

All components are stationary (except for the bladed wheel) thus operational abrasion, failure cannot occur.

The coefficient of efficiency is excellent.

The device can be installed in any size and configuration.

Ease of maintenance : the trays and lamellas can be adjusted, replaced and cleaned while the others are operating and the dismounting, cleaning and replacement of the different elements can be accomplished in a very short time too.

The device can reduce the technologic times as the better oxygen introduction achieved by it accelerates the biologic processes.

Excellent regulating capability. (See above) Partly due to the possibility of stopping and sectioning at will, and partly with the regulation of the pump.

Small structural weight thereby allowing the construction of mobile devices easy to install. During maintenance cranes might not be needed to remove the trays, the suitably dimensioned devices can be moved with human power.

The multi-lamelia aerator cannot be made onto a float but can be installed rapidly an safely on a stage.

An operational advantage of the device is that the multi-lamella aerator is fully above the surface of the water and thus eventual failures area easily detectable.

It can be installed without limits and significant changes into all natural and artificial systems currentty in operation..

As a result of its operating principle, the material transmission processes are not limited to the envisaged oxygen input but significant evaporation take place simultaneously, and as a result, in summer cooling increases significantly the oxygen adsorbing capacity of the waste water, and the comfort of the living environment.

5.-Cooling back the cooling water of power machines (figures 9 and 10) (here the stretched liquid film heat exchanger operates in the form of a counterflow heat exchanger, where the liquid and gas contact freely at all points without auxiliary surfaces, their surface having increase relative to the previous solutions and the transmission coefficient is ideal).

Naturally, the cooling back of all technologic cooling liquids, e. g. oil, water are included too, where contact of the liquid and air is permitted. (e. g. plastic industry, machining industry, metallurgy, steel industry, etc.) The surface in the device is twice of that of liquid film heat exchangers used up to now.

Simple manufacturing, installation.

Problem free operation, hardly sensitive to pollution.

Here the width of the tray depends only on the requirement of ensuring the flow of the liquid, thus high lamella density can be achieved which is a very big advantage in the utilisation of volume.

Since in this case no pollution needs to be considered due to the clean water, the tray can be made of a single material, no additional rim, etc. are required.

The noise level of the cooling towers can be reduced from 120-125 dB to 30-45 dB, if the lower extremity of the liquid film is not allowed to break up into

drops, the stable liquid film is placed instead into the basin area located below or into the tray of the lower stair.

6. Mixing heat exchangers and mixing condensers. (figures 9 and 10) As their name reflet, the media participating the transport process contact directly. The aim is generally to increase the surface. The principle of the stopping-disk liquid film device considered currently the most sophisticated, resembles the principle of our stretched liquid film heat exchanger, but its energy demand is far higher. By placing the stretched liquid films in parallel is possible to achieve s surface competing in dimensions with the surface created by the pulverisation system used up to now, and with the simultaneously exhibited better heat and material transmission coefficient its transmission is better.

Steam condensers represent a special area of use, here the in-flowing dead steam upon meeting the large surface can condense immediately and the water side leaching resistance is not big either.

It is a very great advantage relative to the pulverisation that liquid drops do not get into the gas flow thereby making precipitation dsinecessary.

Degasifiers (figures 9 and 10) To reduce or remove obnoxious or undesirable gases from natural waters, e. g. thermal water. Due to the simplicity of the arrangement the intensive material transmission removes gases most efficiently.

Evaporators. A process similar to the above and extensively used in the chemical industry is where one (ore more) components are removed from a solution containing several liquids of different boiling points by increasing the temperature (distillers). Here too the stretched liquid film humid heat exchangers can be used to advantage, facilitating the liberation of the material being removed.

Gas washers for paint sprayer and other gas washers. In these cases the exceedingly large dimension of the liquid film and its almost plane shape can be made use of. In the washers used up to now either spraying system was used where the liquid was sprayed into the gas in the form of droplets, or the gas was conducted along a liquid film poured over a stop-wall, where the pollutants, (e. g. paint droplets, dust, etc.) retaining their direction of motion

could not avoid crashing and penetrating into the liquid film (and were removed with the liquid). The liquid film can be placed into the gas flow in any number and at any angle., the angle depending on the velocity of the air flow, the number of liquid films in tandem and the required precipitation efficiency.

It is a very great advantage relative to the pulverisation that liquid drops do not get into the gas flow thereby making precipitation disnecessary.

Room humidifier, dust and odour remover, air purifier figure 11.

Under our climatic conditions, during the winter heating season, as a side effect of the generally used central heating the air of the rooms become necessarily dry and dusty. It is of public knowiedge that this condition causes the disease of the respiratory track, or in milder cases, causes unpleasantness.

The regulation of the humidity of rooms has not been solved yet. (99% of the rooms are heated, from among them about 2-3% are air-conditioned and this figure will increase slowly only in the near future!). For this reason a number of room humidifiers have been developed, with the aim of introducing as much water as possible into the air of the room. These devices characteristically are not suitable to clean the air in general.

The geometry of the stretched film permits the room humidifier to have an aesthetic design. Due to its quite operation it can be used in any kind of room. At the same time, its large surface makes it suitable to remove the dust, aromatic material and microbe always present in the air.

It is a decorative element. Architecture, space design has been using the eyes pleasing sight of moving water. Numerus plashes, fountains, cascading water-flows make use of the eyes pleasing play of water.

The stretched liquid film is very showy, it has an almost socking effect. It has the effect of a real water surface which attracts the eyes. Moreover, this water surface is positioned in an astonishing vertical manner. The thin liquid films allows the use of special effects, as the use of coloured liquid films, creation of laser pictures on the surface, coloured illumination, etc.

The liquid film hile acting as a decoration element, can simultaneously carry out the tasks of humidifying, the air and making it free of dust.

The areas of application are public areas, community areas, restaurants, houses.