EP0142595B1 - Method and apparatus for the treatment of pouring water during the pouring by enrichment with co2 and h2co3 - Google Patents

Abstract

1. Process for the preparation of watering water by means of enrichment with CO2 and H2 CO3 , in which CO2 gas which is constantly under pressure is introduced into the water which is flowing through a pipe which has a pressure and temperature approximately identical to those in a normal water supply pipe, characterized in that the watering water is led through a straight flow-channel section forming an impregnation zone and in the process the pressure of the watering water is, at least two partial areas which are at a distance in the flow direction and in each case at the circumference of the flow, momentarily reduced to below the pressure of the CO2 gas by means of an abrupt change in the flow speed, the external liquid layers of the watering-water flow in the impregnation zone being led in each case, at the areas of abrupt pressure reduction, over thin, shoulder-like, cross-sectional widenings of the flow channel section, and in that the watering-water flow is, in each case in the areas of momentarily reduced pressure, ultra-finely impregnated with the CO2 gas, these liquid layers being in each case maintained, immediately after each shoulder viewed in the direction of flow, in a free flow connection with the CO2 gas supply chamber via a plurality of bores corresponding to the shoulder width.

Description

The invention relates to a process for the treatment of irrigation water by enrichment with C0 ₂ and H ₂ C0 ₃ , in which in the through a line with the pressure and temperature approximately equal to those flowing in a conventional water supply line continuously pressurized CO ₂ gas is introduced, as well as an arrangement for carrying out the method, which has an elongated, straight flow channel section which is connected at one end to a pressure source for irrigation water and at the other end to a pouring system or a collecting container and which connects to an impregnation zone with a circumferential connection has a C0 ₂ pressure gas source.

Numerous methods and arrangements for mixing different substances are known.

DE-PS 866 341 describes an arrangement for introducing C0 ₂ into the pressurized water supply line of an irrigation system. An injector is mentioned as a means of introducing C0 ₂ without this being described in detail. Such an injector system, however, is shown in FR-PS-1 171 059. This has a straight flow section through which one of the two media to be mixed flows. In this flow channel, several short pipe sections are arranged consecutively with increasing diameter, the ends of which are overlapped to form an annular gap. The pipe section of the largest diameter is designed with respect to the straight channel so that this also forms an annular gap with the channel. The flow in the channel is thus continuously divided into several partial flows. A device for supplying the second of the media to be mixed is provided centrally on the inlet side of the tube section of smallest diameter, which device introduces this second medium into the flow in a finely distributed manner, e.g. B. sprayed. This is a system in which turbulence that promotes the mixture is generated in a straight flow channel of constant cross-section by a flow control system of several differently dimensioned pipe sections, into which the second medium is injected or sprayed on the inlet side.

From DE-OS-3 117 797 a device for enriching aquarium water with carbon dioxide is shown and described, in which a C0 ₂ gas zone is provided in a device through which the aquarium water is passed in a swirled form.

Finally, from the US-PS-2 899 971 the water feed line z. B. a washing machine a metering device to add an additive, for. B. automatically initiate a water softener. For this purpose, the flow velocity of the water is changed by the formation of a nozzle or a gradual change in the flow cross section. At the end of this section, in which the speed change takes place, a line for the additive opens into a mixing chamber area. At a distance from the mixing chamber area, several holes are provided which are open to the atmosphere and through which small amounts of air can be drawn in. These vents have the purpose when the water supply to the household machine, e.g. B. washing machine, is switched off to prevent a vacuum in the supply line for the water, through which with the additive, for. B. the softener mixed water from the mixing chamber area is sucked back into the water supply. The line section in front of the mixing chamber area should therefore be ventilated by the air sucked in through the bores, and the vacuum that may be present there should be eliminated.

In contrast, the invention relates to a method for treating irrigation water by enrichment with C0 ₂ and H ₂ C0 ₃ . In contrast to water for aquariums or household machines, irrigation water is often required in large quantities in glasshouses and garden centers as well as in agriculture, which also requires corresponding amounts of CO ₂ if impregnation is desired. It should be noted that when the impregnated irrigation water is applied to the plant crops, the water, which is usually applied under pressure, is released to atmospheric pressure. Here are released in large in a conventional manner with C0 ₂ impregnated water amounts of CO ₂ gas, the lost. In addition, in all known methods and arrangements for impregnating water with CO ₂ gas, considerable proportions of the gas in the water are present in relatively large bubbles. These can have considerable disadvantageous consequences in the piping and application systems for the irrigation water. cause. These vesicles clog capillary-like flow paths, such as z. B. be used in the droplet pouring method or in the spraying of water enriched with fertilizers. The flow is impeded by the bubbles.

Furthermore, the release of uncontrollable amounts of CO ₂ leads to a more precise metering of the CO ₂ proportion in the water that is supplied to the plants or the soil becoming impossible. What is said for CO ₂ gas also applies to H ₂ C0 ₃ , since between the physically dissolved portion of C0 ₂ in the water and the portion chemically bound as carbonic acid in the water there is a ratio of about 1000: .

The invention has for its object the method specified at the outset and the arrangement used to carry out the method to further develop in such a way that a much more precise metering of the amounts of C0 ₂ gas and H ₂ C0 ₃ supplied to the plants and the soil with the water is possible and the liquid is so impregnated with C0 ₂ that disturbances from larger bubbles in the liquid are not to be feared and C0 ₂ losses when applying the irrigation water are largely avoided, so that the treatment of cultures with C0 ₂ - impregnated liquid even on a large scale, eg. B. nurseries or farms can be used in an economical manner.

This object is achieved according to the method by the features of claim 1 and with respect to the arrangement used to carry out the method by the features of claim 7. During operation the liquid flows through the straight flow channel section with complete filling. The annular shoulders at the cross-sectional widening points extend radially and are very narrow compared to the flow cross-section. The same applies to the bores, which are each arranged in a ring shape directly behind each shoulder in the wall of the flow channel. These holes represent free flow connections between the flow channel and an outer gas distribution chamber surrounding the channel, in which the CO ₂ gas is kept under a predetermined pressure. This pressure is equal to or less than the mean static pressure in the water flow of the flow channel. For practical reasons, it may be appropriate to set the C0 ₂ gas pressure equal to the delivery pressure in the distribution system used to distribute the impregnated irrigation water.

In the plane of each extension shoulder, the total flow cross section becomes larger and thus the flow velocity of the liquid flow in the flow channel becomes smaller. However, the flow layers near the inner wall of the flow channel are forced in the area of the cross-sectional expansion level to travel a larger distance than the other liquid layers, since they have to flow over the shoulder. The speed of these external layers of liquid is therefore currently greater when such an annular shoulder flows over them, so that the pressure in the area immediately below the shoulders also drops momentarily. This drop in pressure is narrowly limited to the areas below the shoulders. This instantaneous pressure drop acts in the area of the bores arranged directly behind the shoulder in such a way that CO ₂ gas is forcibly transferred into the flow channel through the bores and initially mixes there primarily with the external liquid layers. Due to the immediately following and progressing with increasing distance from the shoulder plane in the overall flow with regard to speed and pressure, the C0 ₂ content is rapidly homogenized in the overall flow.

Since the water is impregnated with C0 _2, in contrast to the known methods, by momentarily generating a negative pressure in partial areas of the water flow, the liquid is impregnated very fine, ie free of larger bubbles. In this, the CO ₂ gas in the liquid is so small and so finely divided that the expansion of the liquid during the application, e.g. B. when spraying or raining, gas losses occurring are very low. So that the impregnated with C0 ₂ gas liquid even in large quantities, for. B. economically in horticultural companies or in agriculture. The proportion of CO ₂ gas and H ₂ CO ₃ supplied to the plants or the soil can also be determined much more precisely, since there is no significant risk of impairments due to uncontrollable gas losses during the application.

The liquid impregnated in this way is largely free of disruptive bubbles, so that it can be applied reliably and without interference even by capillary delivery systems.

Even if several shoulder-like extensions in the flow direction are provided, the overall expansion of the cross section in the impregnation zone is small, so that the speed and the pressure in the flow in front of the impregnation zone and behind the impregnation zone differ only slightly.

The subclaims represent advantageous developments of the new method and the new arrangement.

Under "irrigation water" is normal water or with fertilizer salts or the like, z. B. understood pesticides, enriched water. “Normal” CO ₂ absorption capacity is understood to mean the absorption capacity of normal, ie not chemically pure, water.

While the new method and the new arrangement are primarily described in connection with the treatment of casting liquid, the person skilled in the art can see that they can also be used with particular advantage in the treatment of other liquids with other gases for other purposes.

The new process enables irrigation water to be treated in a way that approximates the conditions that occur in a particularly optimal form in nature in the areas of the earth close to the roots. There in nature, the required negative pressure is generated by the root system as such and the C0 _{2 is} partially emitted by the root system itself or made available as soil-based C0 ₂ , the C0 ₂ in gaseous form at approximately atmospheric pressure and atmosphere Temperature is present.

In the case of large flow cross-sections, it can be useful to direct the liquid flow as a ring flow through the impregnation zone in order to ensure better mixing of the liquid with the CO ₂ gas quantities absorbed.

A further measure, which substantially supports the fine impregnation and promotes the homogeneous mixing of the liquid, is that the gas impregnation zones are followed by further flow channel sections with shoulder-like extensions and underlying bores, which are used for the back-mixing of already completely impregnated liquid with the liquid flowing through the flow channel.

The new arrangement can be used to feed the impregnated liquid directly to a tapping point or consumer point so that the impregnated liquid can be dispensed directly. At consumer points with different purchase quantities, however, it is advantageous if the new arrangement is combined with a supply pressure container in which a supply of finely impregnated liquid is kept ready, the inflow of the liquid taking place through the arrangement according to the invention and the outflow from the liquid supply on the other hand, it is shielded or offset so that any relatively large bubbles present have sufficient time to rise upwards into the gas space in the liquid supply.

The invention is explained below with reference to a schematic drawing of an embodiment.

In the single figure, a pressure vessel with the arrangement according to the invention is shown in vertical section.

In the example shown, the pressure vessel 1 consists of a pressure jacket 2 and cover 3 and bottom 4. A liquid quantity 8 between the minimum fluid level 26 and the maximum fluid level 27 is maintained in the pressure vessel by the sensors shown. In any case, a head space 7 remains above the liquid, which through line 5 with the carbon dioxide gas, under a predetermined pressure of z. B. is kept filled up to 6 bar. The gas is supplied, for. B. via a pressure sensor. a pressure reducer. A drain 6 for the impregnated liquid from the liquid supply 8 is provided in the bottom of the container 4. An impregnation system 9, which is built into the cover 3, is arranged offset in the horizontal direction with respect to the outlet 6. The system 9 has a central throughflow channel, which is connected on the inlet side to a source of pressurized water via a connector 10. The system 9 can e.g. B. sealed by means of flange 11 in the cover 3. In the example 3 shown, the impregnation system 9 has impregnation zones 12a, 12b, 12c lying one behind the other in the flow direction. Before each impregnation zone, the clear width of the liquid flow channel is widened in steps, as shown at 13a, 13b, 13c. As a result, the flow velocity of the liquid changes suddenly as it enters an impregnation zone. Immediately behind the diameter widening are bores 14a, 14b, 14c which are distributed in a shower-like manner and which open into the gas head space 7. In operation, the gas is thus sucked out of the gas head space 7 through the bores 14, so that gas and liquid mix. Since the entering gas remains primarily in the area of the outer layers of liquid, the abrupt widening of the diameter and the resulting abrupt changes in the flow conditions as the liquid enters the next impregnation zone ensure an intimate homogenization of all layers of the liquid flow, which also improves the renewed gas absorption or subsequent impregnation in the subsequent stage. At least two such impregnation zones 12a, 12b are necessary in order to obtain the required fine impregnation.

In order to further promote the elimination of relatively larger gas bubbles in the liquid, the impregnation system 9 is followed by a further channel section 15 axially. In the example shown, this has two backmixing zones 16a, 16b. Here, too, the clear width of the liquid flow channel is changed abruptly before entering a backmixing area to promote mixing. These backmixing areas 16a, 16b serve to promote mixing and homogenization and to reduce the proportion of larger bubbles. For this purpose, the system 15 has an outer jacket 18, closed off from the gas space 7, the lower open edge of which ends below the lowest liquid level 26 in the amount of liquid 8. Through the open end 21 of the jacket and through a downstream outlet opening 20 of the liquid flow channel, already impregnated liquid can be sucked in under the suction effect of the regions 16a, 16b and admixed to the liquid flow in the system 15. The outlet 25 of the system is also below the deepest liquid level 26, so that the escaping liquid cannot entrain any gas in larger bubbles from the head space 7.

The lateral displacement of the outlet 25 of the system 15 relative to the outlet 6 of the liquid supply ensures that any larger bubbles in the liquid have enough time to rise through the liquid supply 8 into the head space 7, so that they do not pass through the liquid withdrawal and thus through the line 6 can be carried away.

If liquid is introduced through the inlet 10, the liquid takes up gas from the head space 7 in the manner described. The liquid keitspiegel 26 rises due to the liquid supplied. The head space 7 is reduced in volume. If this reduction in volume is greater than the gas absorption of the liquid, the pressure in the head space 7 increases at the same time, so that the gas supply via the supply line 5 is switched off. If the gas absorption by the liquid is greater, gas continues to be fed into the head space 7 during the impregnation, so that the pressure is maintained in this space. The pressure in the gas space can, for example, on the line pressure of the irrigation network, z. B. at a pressure up to 6 bar or above.

If the systems 9 and 15 are used for the single delivery or direct delivery of impregnated liquid, the pressure vessel 1 is omitted. The impregnation system 9 is surrounded by a jacket, the annular space of which is connected to the pressurized gas source, while the jacket 18 of the backmixing system 15 at the lower end, as indicated at 22, remains closed. In this case, the flow channel for the liquid continues, as indicated at 6a, to the point of withdrawal.

The difference between the smallest and the largest liquid level 26 or 27 is such that when liquid is removed individually from the pressure vessel 1, the supply of liquid through the systems 9 and 15 is not too frequent, so that a pump supplying the liquid to the inlet 10 is not constantly on - and needs to be switched off.

When supplying large tapping points, the flow cross-section for systems 9 and 15 is significantly increased. In order nevertheless to ensure an intimate, homogeneous mixing across the cross-sectional area of the liquid flow, it is expedient to use a displacement body 30 in the systems 9 and 15, which displaces the liquid in an annular flow through the system. As shown, the displacement body 30 could be gradually or stepwise enlarged in diameter or could also be designed as a smooth cylinder body in the direction of flow.

The cross-sectional shape and cross-sectional change of the body 30 depends on the volume to be enforced and must ensure that the desired abrupt change in speed of the liquid is achieved from the impregnation zone to the impregnation zone.

The arrangement described works reliably both for direct dispensing and for the depicted indirect dispensing of impregnated liquid, namely in a pressure range of approximately 1 bar upwards. The arrangement is therefore particularly suitable for use in horticultural businesses, agriculture and forestry since it can be used for all pressure conditions which occur there, since any compression of the gas in water which is disadvantageous in practice is avoided because of the reduced impregnation pressure. In the commercial sector, the C0 ₂ gas pressure is the same as the output pressure.

Claims (12)

1. Process for the preparation of watering water by means of enrichment with CO₂ and H₂C0₃, in which C0₂ gas which is constantly under pressure is introduced into the water which is flowing through a pipe which has a pressure and temperature approximately identical to those in a normal water supply pipe, characterized in that the watering water is led through a straight flow-channel section forming an impregnation zone and in the process the pressure of the watering water is, at at least two partial areas which are at a distance in the flow direction and in each case at the circumference of the flow, momentarily reduced to below the pressure of the C0₂ gas by means of an abrupt change in the flow speed, the external liquid layers of the watering-water flow in the impregnation zone being led in each case, at the areas of abrupt pressure reduction, over thin, shoulder-like, cross- sectional widenings of the flow channel section, and in that the watering-water flow is, in each case in the areas of momentarily reduced pressure, ultra-finely impregnated with the C0₂ gas, these liquid layers being in each case maintained, immediately after each shoulder viewed in the direction of flow, in a free flow connection with the C0₂ gas supply chamber via a plurality of bores corresponding to the shoulder width.

2. Process in accordance with Claim 1, characterized in that the C0₂ gas is maintained at a pre-determined pressure in a supply chamber near to the impregnation zone, and the outer liquid layers of the watering-water flow in the areas where pressure is momentarily reduced under the gas pressure in the supply chamber are brought into a direct flow connection with the C0₂ gas in the supply chamber.

3. Process in accordance with Claim 1 or 2, characterized in that at least one further area is provided at a distance after the last of the C0₂ impregnation areas, in which further area the pressure is momentarily reduced by means of an abrupt change in the flow speed in the circumferential area of the watering-water flow, and the watering-water flow which is ultra-finely impregnated with C0₂ gas is, for the purposes of mixing back in, brought into a direct flow connection with a partial stream of the watering water, which partial stream branches off at the end of the impregnation zone.

4. Process in accordance with one of Claims 1 to 3, characterized in that the watering-water flow leaving the impregnation zone is led, below the liquid level, directly into a watering-water supply which is ultra-finely impregnated with C0₂ and is within a pressure container, in fact is laterally displaced to a container outlet leading to the withdrawal places, in that a pre-determined delivery pressure is maintained over the liquid level, in a C0₂ gas head space, and in that the C0₂ in the gas head space is kept in a constant flow connection with the circumferential areas, which in each case have momentarily reduced pressure, of the watering-water flow in the impregnation zone.

5. Process in accordance with one of Claims 1 to 4, characterized in that the impregnation-zone watering-water is fed directly, with a pressure between 1 bar and 6 bar, from a supply pipe or from a pressure pump.

6. Process in accordance with one of Claims 1 to 5, characterized in that the watering water is led through the impregnation zone in the form of a cylindrical annular-flow.

7. Arrangement to carry out the process in accordance with Claim 1 with an elongated, straight, flow channel section which at one end is joined to a pressure source for watering water -and at its other end is connected to a watering system or a storage container and which has an impregnation zone with circumferential connection to a C0₂ pressure gas source, characterized in that the flow channel section (13) is widened in the cross-section, in each case by thin annular shoulders (13a - 13c), in at least two areas which are arranged at a distance in the flow direction, in that in the flow direction, in each case directly after each shoulder, a ring of narrow bores (14a - 14c) corresponding to the annular shoulder freely penetrate the wall of the flow channel section (13), which bores open outwards into a CO₂ pressure gas chamber (7), in that a device is provided in order to maintain the pressure in the CO₂ pressure gas' chamber (7) at a pre-determined value, and in that the feed pressure of the watering water and the dimension of the annular shoulders are calculated in such a manner that by means of an abrupt change in speed of the external watering-water flow layers in the area of the annular shoulders, the pressure of the watering water is momentarily lowered below the pressure in the C0₂ pressure gas chamber (7).

8. Arrangement in accordance with Claim 7, characterized in that the flow channel section (13) has at least one further area (16a, 16b) which is subsequently added at a distance to the other areas (12a - 12c), which additional area has in each case an annular, shoulder-like cross-sectional widening (17a, 17b) and a bore ring (22a, 22b) which is associated with the said widening, these bores opening into a distribution channel (19) which, for the purposes of the branching off of part of the watering water which is already ultra-finely impregnated with C0₂ is, near the outlet end (25) of the flow channel section, connected with the watering-water flow.

9. Arrangement in accordance with Claim 7 or 8, characterized in that the outlet end (25) of the flow channel section (13) opens out below the liquid level (26) of a pressure container (3) which contains an impregnated watering-water supply, the outlet (6) of which pressure container is clearly arranged laterally displaced in relation to the flow channel section (13).

10. Arrangement in accordance with Claim 9, characterized in that a device to maintain a C0₂ gas atmosphere at a pre-determined pressure is associated, above the liquid level, with the head space (7) of the pressure container.

11. Arrangement in accordance with Claim 10, characterized in that the bores (14a - 14c) in the C0₂ impregnation areas open out freely into the C0₂ gas head space (7) of the pressure container (3), directly below the annular shoulders (13a - 13c) of the flow channel section (13).

12. Arrangement in accordance with one of Claims 8 to 11, characterized in that an elongated displacement body is concentrically arranged in the flow channel section (13).

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