BRPI0803322A2 - air flow-adjusted flow irrigation and aeration drip system - Google Patents

Abstract

The present invention relates to an air flow-adjusted water flow drip system that elevates water through a water inlet pipe (11) and then distributes water and air together by gravity. Airflow is introduced above half the water column height into a water inlet pipe (11). The water and air outlet bifurcation (13) above the water level (4) is connected to the water and air elevation pipe (12) to accumulate water and promote the interval flow of water and air through the water pipe. drip (14). Thus, the water flow is defined by the controlled air flow by adjusting the air pressure (20). Since it does not involve tubes with an approximate diameter of 3 mm, it is a system little susceptible to clogging that allows adjustment of water flow between 1.0 mL.h-1 and 1000 ml.h-1. Flow adjustment and shutdown in this system is pneumatic. It is also a system compatible with drip controllers according to porous capsules that become air permeable on dry soil.

Description

Invention Patent Report: "AIR FLOW ADJUSTED FLOW DRYING SYSTEM FOR IRRIGATION AND FLOW".

FIELD OF INVENTION

The present invention relates to a new plant drip system which enables the application of even small water flows with low clogging capability without placing too much strain on the filtration system. The system controls water flow and closure by adjusting air pressure. The system is also compatible with a drip controller for automatic soil moisture management. The system can be applied to irrigation of orchards, gardens and domestic environments. By allowing reduced flow rates of liquid with suspended particles, it is a system that can be useful in specialized applications of substrate irrigation, fertigation and even in the application of liquids that have surface tension within the range that water assumes between zero and 60 ° C. .

BACKGROUND OF THE INVENTION

There are numerous drip systems developed mainly from 1970 to apply near water to the root system of plants to save water, prevent erosion and reduce the leaching of mineral nutrients. Appropriate systems for applying drip concepts have encouraged numerous drip developments, some of which are fixed to radial drip manifolds, also called "bubblers", in which the water flow can be adjusted in each of the drip tubes. Despite developments, while drip technology remains expensive and often involves fragile, short-lasting, maintenance-free drip systems. Difficulties of this type have inhibited more extensive drip application, which is still a much less widely used method than drip technology. grooves and sprinkling, although it has many advantages, including the most efficient application of water.

Some of the most important aspects regarding the characteristics of available drip systems, according to the state of the art, were listed by Gilad in 1972 (Gb 1392000), when he described in Israel the preparation of drippers less subject to clogging than micro drippers. tube, making use of injected plastic body containing a maze for water flow. In these labyrinth pathways the moving body of water is forced to sudden changes in its flow direction, which causes energy dissipation, pressure, without the need for holes as thin or tubes as long as the microtubes. With larger holes in the maze and smaller diameter entrances, these drippers were smaller and less subject to clogging. Fifteen years later this foundation was refined in Israel when Gorney in 1987 (US4655397) introduced the vortex dripper. In this new system there are also sudden changes in the direction of water flow along a path with rounded winding designs needed to promote localized vortex circulation. Even with this additional improvement, however, it has only partially been able to meet the criteria of ideality for a dripper, which according to Gillad (GB 1392000) are: a) uniform and low flow drip delivery; b) no clogging of drippers even without the use of sophisticated water filtration systems; c) small drip units for ease of transport and assembly.

Hardison in 1975 (US 3910500) describes an irrigation system very similar to modern drip systems, which also enable the application of soluble mineral nutrients in so-called fertigation. This invention involves the use of a system with at least two sand filters, so that irrigation can proceed while cleaning one of these sand filters by backwash. The use of fertigation systems, as described above, associated with drip, has brought valuable agricultural possibilities, but has further increased the severity of dripper clogging, which remains the major limitation for drip and hose hoses.

Another difficulty for the operation of the defrosting systems is the water pressure. A solution for irregular topography systems where level curves have been raised is described by Boice in 2005 (US 6953156), which uses intermediate float reservoirs at each of the main levels. This water is carried to the hoses with the drippers. The system, however, is complicated to implement because the hoses are positioned, not directly along the contour lines, but rather at a slight unevenness, so that the water pressure is the same throughout the drip hose. Stable water flow, according to the proportionality between the flow and the pressure difference, when the flow resistance is determined by the viscous water transport system, several drippers have been developed that make use of flexible membrane compression and other mechanical devices. drip control devices, such as those considered here, have a flow proportional to the viscosity of the water and, therefore, are devices in which the flow is strongly temperature dependent, since the viscosity of water and other liquids decreases approximately linearly with inverse temperature (MOORE, WJ Physical chemistry. New Jersey : Prentice-Hall, 1972, 977 p.).

Flexible tube and membrane systems include ode Mullett in 1977 (US 4037791) in Australia using a small diameter collapsible micro tube traversed by a copper wire. In these systems, the drippers are placed inside the hose. The increase in water pressure in the hose compresses the micro tube proportionally, because the pressure inside the microtube is lower and is reduced to atmospheric at its outlet. Thus, the water pressure in the hose causes the diameter reduction of the micro tube and thus keeps the dripping flow almost constant over a range of working pressures. The inserted copper wire in the micro tube inhibits the growth of roots or algae and prevents clogging. System feeding is the plurality of micro tubes inserted into the hose, which is a difficulty in fabrication and is a cause of pressure loss in the inner hose, the section of which is partially obstructed by microtubes. Temperature variations in this system cause flow variations not only by the effect of temperatures on water viscosity, but also by the effect of temperature on the components of the plastic materials that make up the dripper. Marans in 1998 (US5820029) in the United States developed a compact dripper to insert externally into plastic hoses. This dripper makes use of a tortuous three-dimensional meander topped by a flexible membrane, which gives this dripper the characteristic of isothermal flow, almost independent of pressure. Similar device of water pressure compensation which makes use of external compression of a membrane is that described by Daigle in 1999 (WO 9902273). Other drippers, in contrast, control the flow through a porous plastic element such as, for example, the Carmo system in 1984 (PI 8402982) developed for use in subsurface irrigation. Porous plastic element of this type, provided that it is elastic, can not only control the flow but also compensate for pressure variations using elastic porous elements. Thus, Smith in 1982 (US 4344576) describes a miniature dripper coupled to irrigation hoses using a plastic, elastic, vaporous membrane placed between the dripper outlet at atmospheric pressure, a rigid and internal perforated clamping plate directly in contact. with water at the pressure inside the hose. As the pressure inside the hose rises, it hardens and punctures the porous and elastic plastic element to give it a practically constant flow within a range of working pressures. These drippers resolve the issue of adjustment with greater or lesser quality. However, they are devices that are still susceptible to clogging caused by irrigation water impurities and suctioned soil impurities. Further, according to Rafi in 2004 (WO 2004098269) which describes in a drip system that uses a small water pressure, pressure controlled drippers of the type mentioned in this paragraph: require high pressure and therefore cause high energy consumption. .

Pressure compensation systems developed with rigid mechanical components include those making use of floats as described by Recanati in 1985 (EP 0222966) of Italy, in which a float adjusts the water level of an open chamber to the atmosphere and then the flow is adjusted into a hole. Similar but more complex is the dripper developed by Mossem 1985 (US 4509692). Also float is the dripper developed by Goodmanem 1988 (US 4753394) which has an elongated structure for insertion into the ground and for irrigation hose leveling. Gonçalves in 2007, in document PI0504094-9, describes a system of optionally timed float pots and a restricted outlet that is not subject to clogging in order to improve irrigation uniformity, using a system that requires low water pressure. Quite different is the pressure compensation through a mold that pushes a spring like that described by Eckstein in 1987 (US 4653695). Other pressure compensation systems are those of water flow, adjusted with a ball that hits a grooved top like described by Mendenhall in 1988 (US4726527). All devices considered in this paragraph, to a lesser extent the latter, are unlikely to clog, either because they involve self-cleaning moving components, or because they have low water pressure inside, so that the flow is controlled in diameter restriction. high. However, the reduction in water viscosity due to temperature increase also causes substantial variations in the adjusted flow rate in these drippers dependent on the passage of water through constraints.

For the problem of dripper clogging, in addition to filter development, a number of improvements have been made to the drippers, some of which are called self-cleaning drippers, although they are not necessarily better than some of the hard-dripping drippers described. in the previous paragraph. A self-cleaning dripper described by Pearce in 1973 (GB 1450684) involves a system in which water and impurities cross a spiral resistor surmounted by a flexible membrane. During the passage of impurity the flow control is impaired, but in general impurity is expelled from the dripper. Another dripper called self-cleaning was described by Werner in 1977 (US 4059228) and contains a series of deformable elements mounted on a more complex structure.

Among the less clogged drippers are also those with anti-siphon mechanism, such as the one developed by Ruskin in 2006 (US 2006255186), which uses a flexible membrane to seal the water outlet when the irrigation water flow is closed. This avoids that the water tension developed in some parts of the hose causes suction of particles from the dripper, which causes clogging, especially in underground systems without protective structures to house the drippers. Rather than an anti-siphoning mechanism, Cohen in 1998 (US 5829686) describes an outlet dripper containing small claws facing toward the water outlet that prevent suction of soil particles that would clog the dripper. Self-cleaning or non-self-cleaning depression-compensated drippers described in the last two paragraphs generally require the use of water under high pressures, and consequent additional energy consumption. Additionally, as in the other drippers considered the reduction of water viscosity due to temperature increase is a factor of substantial increase in flow, which causes a 63% increase in water flow, for example, while the temperature increases from 10 to 30 ° C.

There are also systems with rustic flow adjustment and little clogging, for example for wastewater irrigation. A system of this type is described by Pollock in 1982 (US 4317539) in Edinburgh, in which the water pressure in a set of pipes with a diameter of at least one inch is adjusted in a barostat, which causes excess pressure to dissipate over return water return to the wastewater reservoir. Pressure difference is established by adjusting the flow rate by threading sleeves to level-tipped raised PVCl tubes and containing, at the top, elongated, longitudinal-threaded threads through which water flows. The system is little prone to clogging because it involves the flow of water through a slot with a width of the order of millimeters. The system, however, requires individual flow adjustment on the drippers, and does not allow for greater accuracy.

An alternative to prevent clogging has been the use of high flow drippers, with which water is applied for short periods of time, as described in the Spencer system in 1974 (US 3797741). Of course, high flow drippers make use of larger diameter constraints and thus are less susceptible to clogging impurities. As a matter of fact, this approach to de-temporizing the application of water has been used in many different systems, and perhaps for this reason most drippers today are manufactured for flow rates between 0.5 and 4.0 liters / hour. Possibly, the need to manufacture drippers with larger diameter restrictions, less likely to clog, is the reason for the lack of commercial drippers with a flow rate much lower than 0.5 liters / hour, which would be important, for example, in growing plants on wettable substrates. hard, like coconut fiber. Thus, of course, commercial drippers that had nominal discharges ten to one hundred times smaller and were not susceptible to clogging would be most welcome on the market. In addition, high-flow drippers on low hydraulic conductivity soils cause runoff and obstruction of oxygen inlet through air-filled macro pores, while in highly permeable soils, on the other hand, facilitate subsoil and mineral denutrient leaching. Inspecting, cleaning and / or replacing drippers is often a daunting task because it involves a large number of drippers per unit area, which can only be individually cleaned if the cleaning is done quickly and economically by hand. of work. Alternatively, it would be feasible if all drippers in a system were capable of cleaning simultaneously, for example, with the method proposed by Keren in 2006 (US 0144965) which uses clean water at a pressure lower than a pressure threshold value for pressure compensated drippers, whose resistance to water flow decreases in this condition. On the other hand, dripper replacement, when this is possible, is generally a low quality process as the fixing burrs cause damage to the pipe during dripper removal, so that after a new dripper is fitted Leakage is common. Thus, dripper clogging has caused great bonuses to producers, who generally discard dripper pipes after just over a year of use. ,

Dripping in addition to water and soluble mineral nutrients may also apply oxygen for underground irrigation of compacted soils where oxygen transport to the roots is restricted. In this sense, Mazzei in 2004 (US2004005193) presents a system of application of water and micro air bubbles, in a device that prevented uneven irrigation, caused by accumulation of natubulation air. According to this document, air bubbles are reasonably stable, but they progressively separate from water and the air accumulates in the highest places from whose drippers mainly air flows. Thus, in the system in question there is a water level sensitive device that allows air to escape and prevents the passage of water. This reduces the variability of irrigation at the same time that oxygen is supplied to plants. However, uneven distribution of air bubbles can cause drip variability and localized air application variability. Another way to apply air to improve soil aeration and plant productivity is through the Potts drip system proposed in 2005, US 6959882. This system involves the use of 35 kPa soil water pressures and 2 kW pressures. , 5 to 25 kPa for air application. In this case, air and water applications occur separately in time. In these systems the water flow in the drippers is also influenced by temperature through its effect on water viscosity.

The use of air in combination with irrigation systems may also target irrigation management at controlled water stresses as described by Caibo in 2000 (PI 0004264). In this document, the use of forced air passage through porous capsules with critical stresses or bubbling pressures (Pb) defined in the manufacture is described. The system works linearly for the soil water tension, as if it were a tensiometer, which operates between zero and a water voltage of magnitude equal to the Pb module. The uses of the gaseous irrigation control system are for measuring the voltage of the soil water and irrigation tensiometric management, with or without automation, but this is not a specific system for adjusting water flow in drippers.

Other documents that also describe the use of air in drip irrigation systems refer to US4519546 and US 4781687 patent systems utilizing air bladder and air bladder, respectively, to control pressure and flow for agricultural and medical applications, respectively. Physically, these systems also have temperature-dependent flow rates and the effect of this factor on water viscosity. US 4174067 utilizes a source of pressurized liquid; a means (usually a plastic pipe with small slits) for conducting the source liquid to individual irrigation points; a source of compressed air connected to the liquid passage and a control to temporarily stop the liquid supply and to supply compressed air and thus the air is used as a tool to unclog the drippers, drip slots.

Drip manifolds and hoses radially attached to a head, as described in US 2004074997 (Sacks, 2004), allow convenient connection to water manifolds and at the same time have a simple way of adjusting flow for drippers, including the possibility of closure for the exchange of hoses in a register. Other "bubbler" drip radial dispensers are described in documents such as: de Olson (1991, US5054690) which has a small filter and several drippers; Mendenhall System (1988, US 4726527) which uses flow controlled outputs through metal ball drippers; and Goodman's system (1988, US 4753394), which makes use of a float to reduce pressure and level kurtosis manifolds to conduct water. Radial drip distributors. They facilitate fruit irrigation and are useful in gardening, but they do not involve novelties in terms of how they control the flow of water, or the ways to reduce the clogging of drippers.

The need to reduce soil water evaporation, competition from invasive plants and dripper clogging by suction of soil particles has been some of the main reasons for the development of drip protection accessory structures. Thus, in the York & York system in 1992 (US 5102259), for subsurface irrigation, a widened and capped base device is used in which the dripper is protected. The installation is made in a depth-depth cavity suitable for irrigation. In the 2003 Ogi system (US 2003017001), water and oxygen are carried to the roots in compacted soils, especially in urban environments, by a porous tube of adequate length. In this system, water flows down the sides of the porous wall of the sandbar device. In the 1988 Mangels & Candy depletion shield (US 4765541), the water emitter is placed in a capping cylinder in which the dripper is inserted. Some drippers specifically have an elongated body for insertion into the soil and also allow for subsurface irrigation to the appropriate depth, such as the 1979 Hartmann dripper (US 4153380), which uses a float and a hole to adjust water flow. .

In order to reduce the difficulties considered above, the present invention describes a simple and practical irrigation system, which even enables the application of very low water flows. The proposed system innovates by adjusting the water flow by applying an air flow that elevates the water that then flows into dripping pipes, in which the air flow and the water flow itself are adjusted. Applying air and water in a single tube is a system in which the flow rate can be adjusted, turned on and off pneumatically. In addition, the system may supply the roots with oxygen in the case of compacted soils, or may use air input as the triggering energy for irrigation management using a gaseous irrigation control device. {SUMMARY OF THE INVENTION

The present invention relates to an air flow-adjusted flow drip system that elevates water in a water inlet pipe (11) and then conducts it with air through a drip pipe. Thus, since airflow adjustment systems are unlikely to clog, then the application of airflow-adjusted drip is also unlikely to clog, even if water flows are reduced to the order of 1.0 mL.h " 1. The conduction joint air and water is a differential of the present system, whose flow can be adjusted and pneumatically turned off.In addition, the system is compatible with a drip controller, using drip caps sensors, which become air permeable when in equilibrium with soils under water stress greater than a given critical characteristic value of the sensor Unlikely to be suspended particulate matter clogging the present irrigation system is suitable for traditional irrigation, fertigation, pesticide application and even special spraying with other surface tension liquids. preferably greater than 0.040 N / m.

The present invention relates to an irrigation and aeration drip system characterized by having an air compressor (19); water reservoir (17); lid (18); overflow tube (2); float (3); container (15) containing hole (16) in the upper region; air distributor (8); restriction (9); air inlet pipe (10); water inlet pipe (11); water and air lift pipe (12); bifurcation (13) connecting the water and air lift pipes (12), water inlet pipe (11) and drip pipe (14). The system of the present invention is characterized by comprising the following steps in operation:

(a) water inlet through the water inlet pipe (11) contained in the water reservoir (17), the level of which is adjusted by a water depression controller, overflow pipe (2) and float (3), for example;

b) air inlet from the air compressor (19) through a pipe (7) to the air distributor (8) from which the air flow is controlled by passing a restriction (9);

c) passage of air through the air inlet pipe (10) causes a. water inlet in the water inlet pipe (11) which is opened in the base (6); d) in the crossing between the water inlet pipes (11) and the drainage pipe (14) the pressure is accommodated in the water inlet pipe. water ear (12);

e) from the water and air lift pipe (12) water and air are passed to the drip pipe.

The system of the present invention may have float pressure control (3) replaced by differential valve (36) without loss of performance. These valves are particularly useful for the use of the present invention.

In the system of the present invention the drippers may preferably be arranged in radial or panel arrangement and may flow through a subsurface applicator to improve localized application and to reduce the possibility of clogging at the outlet of the drip tube (14) or at the outlet. of defrost controllers (32).

The system of the present invention is ideal for dispensers with an undetermined number of drippers. Because it enables reduced liquid flow adjustments, even with suspended particles, it is a system that can be useful in specialized applications for substrate irrigation where low flow rates and ideal use with fertigation are ideal.

BRIEF DESCRIPTION OF THE FIGURES

Figure 1: Illustration of the drip distribution system, arranged in an arrangement, with a view of two drippers on the sides.

Figure 2: Mini compressor, air exhaust pressure regulator, rnanometer and air distributor.

Figure 3: Detail of a drip pipe connected to a radial irrigation distribution system for use in shrubs and gardens.

Figure 4: A device in which the flow of water carries air with the aid of a water and open air riser to the atmosphere in order to introduce air and prevent siphoning from generating loss of flow adjustment.

Figure 5: Irrigation device using air or other gas, introduced together with water to close the water outlet in irrigation management, according to porous elements that become impermeable to air as the soil is sufficiently moistened as per the sensor characteristic. Figure 6: Scheme of application of the drip system in a single-protection underground structure (A) and in a protective underground structure containing a drip controller (B).

Figure 7: Drip device with water flow adjusted by a flow of air, or other carrier gas, mounted on a panel in which the differential valve controls the water level or reference pressure in the system.

Figure 8: Device with seven panel-mounted drip tubes in which the flow rate of each water outlet is adjusted by its air flow, as in Figure 7.

Figure 9: Air flow-adjusted, or other gas, drip-mounted drip device in pressurized assembly, connected to three irrigation controllers with porous element groundwater voltage sensors. Figure 10: Adjusted water flow chart depending on the air flow in the drip system (Fig. 1), operating with a 3 mm internal diameter lifting and drip tube.

Figure 11: Graph of air flow and water flow through a drip device (Fig. 4) operating with a 7 cm water column pressure gradient and having 3 mm internal diameter riser and drip tubes.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to an air flow adjusted water flow drip system. The system is convenient not only for practically drip clogging-free operation, even when operating with very low water discharges, but also as a way of applying air through the drip tubing when soil aeration is required or improved. automatic irrigation control, driven by compressed air.

According to the present invention, the drip system is composed of the following elements (Figure 1): water reservoir (17), cap (18), overflow pipe (2), float (3), container (15), distributor (8), restriction (9), air inlet pipe (10), water inlet pipe (1), water and air lift pipe (12), bifurcation (13), drip pipe (14) . In Figure 1 it is further shown that a pressure controller, overflow tube (2) and float (3) adjust the water level for a plurality of drip tubes (14) from the water inlet tube (1). )under pressure. Control of water pressure to level (4) is done by closing the overflow pipe (2) by the float rubber (3). The water reservoir (17), with lid (18), has internally a container (15) for the float (3) to which the overflow pipe (2) and other components are attached. This container (15) also has an upper orifice (16) for balancing with atmospheric pressure and orifice (5) in the base for entering water.

To produce drip (Figure 1), air enters through air distributor tube 7, has its flow controlled at a restriction (9), passes through air inlet tube (10), raises water in the inlet tube. water (11), which is opened in the base (6) and goes to the drip tube (14). A bifurcation (13) couples the tubes (11), (12) and (14) in the system. At the crossing between the tubes (11) and (14) the pressure is accommodated by the water and air lifting tube (12). The water and air lift pipe (12) is critical so that the average water flow obtained is not influenced by the height at which the tip of the drip pipe (14) is placed. This effect is obtained by the fact that water accumulates in the water and air elevation pipe (12) and then spontaneously flows through the bifurcation (13) and pipe (14). In this interval flow, the rapid fall of water may cause additional air drag which is sucked through the water and air lift pipe (12) thereby preventing the occurrence of siphoning and allowing air to be conveyed through the drainage pipe. Thus, the average air flow exiting to the drip tube 14 is not necessarily equal to the inlet air flow used to adjust the drip flow.

It is important that the drip tube is always placed with downward inclination so that air and water flow out. It is also important that the air and water lift tube 12 have a diameter of the order of 5 to 7 mm so that the spear escapes without dragging water droplets during the time the water pressure increases until spontaneous flow occurs. .

In Figure 2 it is observed how an air compressor (19), for example, the membrane injects adjusted air flows into the drip system, using the restrictions (9). In place of the air compressor a compressed air cylinder or other gas such as N2 can also be used. The adjustment of the air flows can be done in two steps: first, the air pressure in the air pressure relief valve (20) is adjusted, in the case of the use of a membrane compressor, and then the air pressure is determined. air flow under standardized restrictions (9). These airflow capillaries (9) may be of various types, for example, but not limited to, prepared with flexible electric wire segments, which contain capillary air passages between the cylindrical metal filaments disposed within the plastic wrap of the wire. The restriction should preferably adjust for the largest air flow required to obtain the highest water flow in the dripper that you wish to use during the crop cycle. Thus, reducing the working air pressure at the air pressure control valve (20) according to the manometer reading (21) reduces the drip flow to the value required under a given condition. If another type of compressor, or air or compressed gas tank is used, then the air pressure adjustment is made and the non-exhaust depression adjustment valve, which does not cause any change in system operation.

Drip shutdown is achieved by turning off the dear compressor (19), or by reducing the pressure at the air pressure control valve (20). Of course, the water flow is reduced to zero if the applied air pressure less than the height difference between the air inlet of pipe 10 and the water surface level (4), which is zero pressure in the system.

Adjustment of air flow through all air inlet tubes (10) simultaneously is achieved by regulating the air pressure in the air depression control valve (20). The constraints (9) and the air distributor (8) are accommodated on the radial drip distributor top (22) (Figures 1, 2 and 3), or on top of the panel drip systems (Figures 7, 8 and 9). The location of the top flow control constraints (9) is important so that no water movement occurs for the air constraints (9), which would cause temporary obstruction to the flow of air flow.

For timed use the air compressors can be turned off directly by an electrically actuated or valve solenoid-actuated timer. During plant development the amount of water applied may be increased by increasing the irrigation time or alternatively by increasing the air pressure at the air pressure control valve (20). The system of Figure 1 is seen from above in Figure 3 to show how can be the radial distribution of the drip hoses. In this arrangement water is taken from the main pipe (23) through the water inlet pipe (1). Both radial drip arrangement and panel arrangement (Figure 8) are effective ways to apply drip to individual plants in orchards and gardens.

For operation without an air compressor, in a slightly clogged embodiment, the dripper can operate at the flow rate by obtaining a water column height pressure through a restriction (24) (Figure 4). In this system with pressurized water (1) and pressure control with overflow pipe (2) and float (3), air is drawn into the drip pipe (14) as water accumulates in the water lift pipe. and air (12) sufficiently to be accelerated at flow intervals in a process that sucks and drags air through the pipes 26 and 14. In this embodiment, the outlet bending height (13) for the drip pipe (14) it is below the water level (4), so that the small water flow rate is spaced with the introduction of air into the drainage pipe. The optional cover (25) is for cleaning the restriction (24) with a steel frame. This simplified system does not allow the flow and pneumatic closure controls of the irrigation, described for the preferred system, which uses air compressor.

Drip according to soil moisture

Figures 5 and 6 show an irrigation controller that is driven by air driven in this drip system. As water and air introduced through the drip tube (14) into the drip controller chamber (32), the rising air separates from the water occupying the base. On damp ground (35) (Figure 6) the porous sensor capsule (31) remains impermeable to air and thus air accumulates slowly in the dewatering controller chamber (32) until the float (27) sinks and closes. the water outlet pipe (29) by compressing the sealing rubber (28). In this state the pressure in the deflector controller (32) increases and the drip ceases. When in the drying phase the soil water tension exceeds a critical value characteristic of the sensor, then the irrigation controller air (32) passes through the tube 30 and escapes through the porous capsule of the sensor (31) and the water accumulates. again causing the float (27) to rise and dripping to resume until the soil moistens again. Porous capsule sensors, called Irrigas, with different bubbler pressures, critical stresses, are commercially available (BR PI 0004264), so this is a new way of applying this drip system associated with porous decapsule sensors. The difference, in this humidity control application, is that both water archers are introduced through a single tube, which facilitates field applications.

Since the air and water pressures induced by the present invention system in the drip controller are less than 1 meter of water column, then it is simple to demonstrate by the relationships between force, water outlet pipe section area (29) and pressure that the weight of the float required to close the water outlet (29) is small and may even be less than five grams. Therefore, it is known that these drip controllers (32) can be manufactured with miniature dimensions, ie with a total volume of 50 milliliters and even. Miniaturization facilitates the economic viability of controllers because they are cheaper and more aesthetically suitable for potted plants and daytime environments.

A specific detail of the drip through the irrigation controller is that in this case there is no need for uniformity in water flow.

Thus, in this application there is an interesting freedom of choice for the air compressor, which neither needs to generate stable air pressure nor constant air pressure. Thus, they may be used in conjunction with the present invention, but not limited to, solar panel driven air compressors and thermo-compressors as illustrated by Caibo & Silva (Irrigation System for Irrigation Management: Fundamentals, Applications and Developments. Brasilia: Embrapa Vegetables, 174 p, 2005, ISBN 85-86413-07-0).

The air flow to the drip tube 14 depends on the air flow through the compressor, the amount of air that is lost through the water and air riser tube 12, and the amount of air that enters the lift tube. water and air (12) when, at intervals, water flows into the drip tube (14). In drip controller systems (32), when the drip controller closes water accumulates to a maximum value in the water and air lift pipe (12), while air flow continues to escape, in this case without dragging water, up to that the drip controller (32) opens again. Subsurface drip

In Figure 6A a dripper applies subsurface irrigation aided by the drip tube (14) inserted into a protective tube (33) with perforations (34) and arbitrary dimensions, for example, 50 mm in diameter by 600 mm deep into a bush. In figure 6B the drip pipe (14), together with the drip controller (32) make use of a similar protective pipe (33) for irrigation. This protection tube (33) is an accessory that enables irrigation to be applied to the desired depth. Soil particles and root growth are possible causes of clogged pipes and drippers, especially when using subsurface irrigation. Pipe protection (33) with perforations (34) is a cheap accessory that can be sized and even prepared in the field to reduce this problem in the system.

Differential valve system

Figure 7 illustrates a simple system with entrained water flow using a differential valve (36) to adjust the inlet water pressure (1). This system differs from the system illustrated in Figure 1 by the use of a differential valve (36) to control the pressure in place of the float (3), and in that it is a panel mount that can be attached to different supports with greater ease. All other components used are analogous to those described in Figures 1 and 2. The difference between this differential valve system and the system illustrated in Figures 1 and 2 is that at the beginning of operation of this system the water pressure or level (4) is adjusted at the valve. differential (36) before starting the air compressor (19).

To do this, remove the differential valve cap (36) and tighten or loosen the internal spring. The air flow adjustment is also made through a restriction (9). This trapping through the pipe (10) enters the pipe (11) and raises the water through the water and air lift pipe (12). This elevation of water causes interval flow, whenever water accumulates in quantity in tube 12. Interval flow of water for dripping in hose (14), with air drag, occurs with the passage of these fluids through the bifurcation (13). Drip valve using differential valve can also be applied to a panel with multiple drip outputs. Figure 8 illustrates a drip system with air flow entrained water flow with differential valve (36) in a panel with 7 outlets for vessel drip (14) and a water dispenser at the base (40). The system of Figure 8 is just a practical enlargement of the same components as Figure 7 to cater for dripping a larger number of plants.

The pressure stability with which water enters the water pressure control differential valve (36) or the overflow pipe system (2) and float (3) should be of the order of 20% or better and preferably at rated pressure. from 20 to 50kPa. This is important because pressure adjustments, ie water levels, made by these valves must be accurate to within 0.1 to 0.4 kPa. The differential valves (36, 38) considered in this invention are similar to those used for liquefied petroleum gas pressure control in that the outlet pressure can be adjusted as a differential compared to the reference pressure applied to the central membrane.

The system can also be used more precariously for operation without air compressor. In this case, as illustrated in Figure 4, it is the water pressure gradient that drags the air flow using the water lift tube ear (12), which allows air to be introduced into the drip tube (14). For air compressor operation, in a slightly more clogged embodiment, the dripper may operate at the obtained water flow by dissipating a pressure from the water column through a restriction (24) (Figure 4). In this system with pressurized water (1) and pressure control with overflow pipe (2) and float (3), air is drawn into the drip pipe (14) as water accumulates in the water and air lift tube. (12) in sufficient amounts to be accelerated at flow intervals in a process that sucks and drags through tubes 26 and 14. In this embodiment, the height of the outlet bifurcation (13) to the drip tube (14) is lower at water level (4), so that the small flow of water is spaced with the introduction of air into the drip tube. The optional cover (25) is for cleaning the restriction (24) with a steel wire. This simplified system • does not allow the flow and pneumatic shutoff controls of the irrigation, described for the preferred system, which uses compressed air by air compressor or air cylinder or other compressed gas.

Air flow controlled water flow dripping in a pressurized system, as illustrated in Figure 9 is more complex and only allows the use of a drip tube per water pressure control differential valve (36). Thus, pressurized systems as illustrated in Figure 9, preferably should be coupled to one or more drip controllers (32) connected to the long length of the drip tube (14) to irrigate various plants or pots (37).

The pressurized system can also be mounted with a float (3) making an airtight, non-leaking reservoir and safety valve resting. This option, however, is not illustrated, because it is a more difficult system to dismantle and because it requires more care.

The pressurized system illustrated in Figure 9 makes use of compressor (19), and air pressure controller for introducing controlled air flow through a restriction (9). A water flow control differential valve (36) adjusts the pressure directly to the water inlet pipe (11) according to the gaseous pressurization acting on its reference. The gaseous pressurization of the reference is applied using the restriction (39), which receives controlled pressure air from the differential air pressure control valve (38). The differential valve of. air depression control (38) is also hermetically connected (41) to the top of the water and air lift pipe (12). The total water pressure at the differential valve outlet (36) is equal to the pressure set on its internal spring, plus the air pressure set at the differential air pressure control valve (38). Water flows to the drip tube (14) at intervals, making use of the air and water lift tube (12) as a means of adjusting water pressure in the same manner as has been explained for the apparatus of Figures 1, 7 and 8. A The difference in the pressurized system in Figure 9 is that the obstruction of the water flow in the drip pipe causes gas pressure increase in the water and air lift pipe (12), where the pressure with the closed system approaches the pressure in the pressure control valve. (20), which is read on the pressure gauge (21). This response is what happens, for example, when the water flow in the irrigation controllers (32) is closed. The quality of the pressurized system is to enable the movement of water from the drip tube (14) with greater pressure. This additional pressure is valuable if it is difficult to position the drip tube downward with sufficient inclination for water and air to flow without restriction. This additional pressure, therefore, contributes to the water movement overcoming any "bellies" along the drip tube (14).

By default, the pressurized system would be costly to irrigate only one plant. Thus, the pressurized system is more interesting by coupling a plurality of irrigation regulators along the drip tube (14), as illustrated in Figure 9.

Another quality of this pressurized system is to apply drip irrigation at regulated water tension to the air pressure control valve (20).

Thus, for example, with commercially available 15 kPa Irrigas miniature porous capsule sensors, dripping at water voltages ranging from 5 kPa to 10 kPa can be safely applied. The equation used in the system conforming to PI 0004264 is: T = Pb - p, where T is the soil water tension, Pb is the porous element's burst pressure and p is the applied air pressure.

For the sake of safety, due to the variability of commercially available porous capsule sensors, and the fact that the pressures to start bubbling are greater than the pressures to stop bubbling, then it is advisable to use air pressures p such that p <0.6xPb .

Differential pressure regulators, differential valves (36) and (38) should preferably behave similarly to the controllers used for LPG flow control in that they allow fine and stable pressure adjustments from 5 cm to 300 cm of water column. by adjusting the spring pressure. Differential valve (36) The spring is hidden by threading and sealing the air inlet in the reference. In the valve (38), the spring pressure adjustment can be seen, to facilitate the adjustments as read in pressure gauge (21).

System Adjustments

In the systems illustrated in Figures 1, 7, 8 and 9 the rising height of the water measured in relation to the surface or water level (4) must be less than the distance between the hole (6) in the pipe base (11) and the insert. from the air inlet pipe (10), from which water flows levelly through the bifurcation (13), to the deflate pipe (14). This condition ensures that air can raise water through the pipe.

(11), without the occurrence of air bubbling in the hole (6) of the tube (11).

From the point of view of water flow the diameter of the pipes and the type of connection between the pipes 10 and 11 are relevant. Tube (11) should have a diameter of 2 to 4 mm in order as smaller diameters restrict water flow and with larger diameters the system may cease to function due to loss of stability as air rises through the water from the pipe without raising it above the bifurcation (13).

The water and air lift pipe (12) should have a diameter of the order of 5 to 7 mm, and sufficient height to hold water and allow air to rise through the water retained in the pipe (12). After sufficient accumulation of water, the water and air riser pipe (12) prevents water from siphoning because it allows air to flow freely into the drip pipe (14), while water flows spontaneously through the fork (13) and through the pipe drip (14) without forming sufficient vacuum to cause siphoning.

Experimentally, the effect of decreasing the water pressure gradient between the water level (4) and the fork outlet (13) in the range from 80 mm to 20 mm is modest. Thus, an elevation of 50 to 80 mm is a safeguard against minor deviations in water pressure adjustment, whether on float (3) or differential valve (36) .The error in water pressure adjustment on these accessories (3, 36 ), preferably should be less than 10 mm. If the variations are greater then it is important to adjust the inlet water pressure in the system. This is done by using water from a water box or a pressure control valve in the line. A 20 kPa valve would be adequate.

Physical aspects

Accordingly, the drip system of the present invention is much less influenced by temperature than other drippers, because its operation depends more on water surface tension and air viscosity than water viscosity which is the most important physical variable relating to temperature and temperature. flow in other types of drippers. The system also has the quality of applying water flow and air flow simultaneously in a single pipe for drip irrigation and soil aeration applications.

The term water used in the present invention refers to water, solutions, and other liquids with surface tension preferably greater than 0.030N / m. In the present irrigation system there is the possibility of irrigation only with water and also with the application of nutrients through solutions and suspensions (fertigation).

According to the present invention, water and solutions refer to: a) Water, fluid without impurities which by its size or agglomeration may cause clogging of tubes 11, 13, 14 or 29. In agricultural practice the elimination of these impurities involves in general the use of sand filters, for example; b) Solutions with mineral nutrients, called nutrient solutions, which contain essential mineral elements, such as nitrogen and potassium, which promote plant development. These solutions are usually prepared by dissolving water-soluble salts; Suspensions refer to relatively stable, unmoulded suspensions that may clog the tubes.

One caution with the dripperlines of this invention is to prevent the "belly" hollowness in the hose from exceeding half the total water column height of the system. For this, drip pipes (14), with a maximum length of 3 meters, should preferably be disposed downwards. The tip of the drip tubing can be fixed to align the tubing and facilitate flow. The use, pressurized systems and the installation of the distributors, panel, for example, installed about one meter above ground level or the table with pots assist in the proper functioning of these systems. In this regard it is also important to note that as the use of drip controllers the installation height of the drip dispensers becomes more critical, without these devices there is no problem that these devices are installed at a height greater than 1.0 m. With the use of drip controllers the additional pressure given needs to be discounted as per the formula treated with pressurized systems of Figure 9.

For correct operation, it is important to check the air pressure in the manometer (21). Accidentally shutting off the air compressor (19) reduces air pressure and turns irrigation off. Thus, maintaining the set pressure is an indication that the system is applying the correct water flow.

The drag of water by an air flow in this system is a phenomenon that depends on temperature through its modest influence on increasing the viscosity of gases, air, on decreasing surface tension of water and which is also influenced by the stronger effect of increasing temperature to reduce Thus, between zero and 40 ° C the water viscosity decreases almost threefold, from 0.018 poise to zero Celsius to 0.0065 poise at 40 ° C, while in the same temperature range the surface tension of the water is reduced by only 8%. At the same time, and most importantly, the viscosity of gases, air, is proportional to the root of the absolute temperature, so that this viscosity increases by about 7%, rather than decreasing, in the temperature range considered. The influence of these three properties on the system of the present invention is dominantly weighted, however, for the effect of temperature on air flow through constraints (9) and (39), which is mediated by increasing air viscosity as a function of temperature. On the other hand, the dragging of the water in the pipes (11, 12 and 14) depends on the work required to move water and air bubbles according to the surface tension of the water, the viscosity of the water, the pipe shrinkage and the diameter of the pipe used. case around 3 mm. Thus, due to the dominant role of air flow and surface tension of water, the system of this invention has a water flow influenced by temperature differently from that which occurs in other drippers, whose flow is controlled according to restrictions in which only the viscosity Water is generally the property most influenced by temperature.

Another physical aspect of dripping is the wettability of the medium. Thus, currently, soils, due to pollution, and the substrates, by their organic components, have particles coated with hydrophobic substances that make water retention difficult. In order to properly irrigate in such cases, the availability of a drip system such as the one of the present invention that enables the application of very small plots is important. Applied under sufficiently low drip flow rates, even in these media it enables the development of a demolishing bulb that can approach spherical, less elongated, in the soil, or that can dampen the entire vessel substrate. This watering is fundamental because it enables the roots of the plants to better explore the environment from which they draw water and essential nutrients for their development.

Usage examples

Following are some examples of use of the drip irrigation system of the present invention. These examples represent a better way of elucidating the operation of the system and do not limit the present invention.

Airflow induced water flow test

Figure 10 illustrates the typical variation of water flow as a function of the applied air flow "in the dripper of this invention. In the case of this test, air entered 50mm below water level (4) which was raised to 50mm above this level. drip pipe (14) The flexible black PVC drip pipe had a length of 1.0 meter, an inner diameter of 3.0 mm and was accommodated with a height difference of 250 mm with respect to the water level. (4), for the test In Figure 10, it is found that the water flow initially increases linearly with the air flow, according to a slope of approximately 0.5. as low as 5 milliliters per hour if capillary restraints (9) are used which allow, for example, an air flow of 100 milliliters per hour using an air pressure of 20 kPa at the air compressor outlet (19). between air flow and pressure applied through restriction (9) is given by the modified gas Poiseuille equation (MOORE, W.J.Physical chemistry. New Jersey: Prentice-Hall, 1972, 977 p.). For small pressure differences, however, the linear approximation can be made, neglecting the compressibility of this fluid. Thus, by reducing the pressure from 20 to 1 kPa the air flow is reduced from 100 milliliters per hour to 5 milliliters per hour, and according to Figure 10 this air flow would determine a water flow in the order of 2.5 milliliters per hour. hour. A relevant detail in this case is that the applied air pressure must account for the difference in the level of insertion of the air inlet pipe 10 into the pipe 11, with reference to the water surface level (4). -.

The maximum water flow illustrated in Figure 10 is not high compared to typical commercial drip values, which usually have flow rates between 0.5 and 4.0 liters per hour. Reduced drip flows, however, are one of the valuable aspects of the present system, as applied flows should not cause soil siltation, nutrient leaching below root depth, or cause maintenance of substantial soaked soil volumes as the dripper exits. . In the latter case the proposed system still helps because it forces the introduction of air along with water.

Airflow carried by water flow

Figure 11 shows the experimentation of the system without the use of the compressor (illustrated in Figure 4). In this experiment it is found that the water flow adjustment of the system of Figure 4 is easily accomplished by setting the water pressure gradient or column. Even more interesting is that air flow, as well as water flow, was also controlled by the applied water pressure gradient, this without saturation effect within the range of studied water column gradients. In the experimentation of the system, the drip occurred through a 1.0 meter long plastic tube, with an internal diameter of 3.0 mm and with the outlet located 250 mm below the insertion of the water elevation tube (12). simulates a less favorable situation than the installation with the system placed at a higher height, for example, one meter. Still, it should be borne in mind that the air flow in the water-entrained air system is controlled less tightly than the air-entraining water flow, since in the field the height of the drip outlets is uneven.

Claims (17)

1. Irrigation and aeration drip system characterized by having the water flow adjusted by air flow. 2. Irrigation and aeration drip system characterized by having air compressor (19); water reservoir (17); lid (18); overflow tube (2); float (3); container (15) containing hole in the upper region (16); air distributor (8), restriction (9); air inlet tube (10); water inlet pipe (11); water and air lifting pipe (12); bifurcation (13) by connecting the air and water lift pipes (12), water inlet pipe (11) and drip pipe (14). Irrigation and aeration drip system according to claims 1 and 2, characterized in that it comprises the following steps: a) water inlet (6) through the water inlet pipe (11) and water level (4) set by the controller pressure control with overflow pipe (2) and float (3), b) air inlet from the air compressor (19) through an air pressure control valve (20) and pipe (7) to the air distributor ( 8) where the air flow is controlled through standardized constraints (9) and driven by the pipe (10) c) the air flow through the air inlet pipe (10) raising the water in the open water inlet pipe (11) d) at the crossing between the water inlet pipes (11) and the drip pipe (14), by the bifurcation (13), placed above the controlled water level (4), the excess pressure is accommodated. in the water and air lift pipe (12), where part of the air escapes into the atmosphere; e) from the lift tube (12) water and air are pushed through the bifurcation (13) to the drip tube (14). Irrigation and aeration drip system according to claim 3, characterized in that the air flow control is carried out by the steps of: a) adjusting the air or gas pressure from the air compressor (19) or air cylinder compressed or other gas in a pressure control valve (20) b) determination of air flow under standardized constraints (9) c) downward flow of water through the drip tube (14) from the installed system that the water level (4) is preferably one meter or more above ground level or above the potable area to be irrigated. Irrigation and aeration drip system according to claims 1, 2 and 3, characterized in that it controls the flow of water, liquids and nutrient solutions with sufficient surface tension to be raised through the lie-12 tubes by adjusted air flow. Irrigation and aeration drip system according to claims 1, 2 and 3, characterized in that the liquid inlet (11) and drip (14) pipes have an internal diameter of 2 to 4 mm. Irrigation and aeration drip system according to claims 2 and 3, characterized in that the water and air lift pipe (12) with a diameter of the order of 5 to 7 mm allows the accumulation of water pressure while part of the air flows through the water in the pipe. Irrigation and aeration drip system according to claims 1, 2 and 3, characterized in that the flow adjustment and drip shut-off can be achieved by reducing the pressure in the air depression control valve (20) or turning off the air compressor (19). Irrigation and aeration drip system according to claim 1, 2 and 3, characterized in that the regulation of the water pressure can be done in a differential valve (36) instead of a float (3). Irrigation and aeration drip system according to claim 9, characterized in that it can be mounted in the form of a panel with a water dispenser at the base (40) and several drip outlets (14). Irrigation and aeration drip system according to Claims 1 to 10, characterized in that it conducts air and water in a single drip tube (14) to which a drip controller (32) which is provided with the water to close can be connected. water output in irrigation management, according to the response of porous capsule sensors (31) that become air permeable as the soil dries above a critical sensor voltage. Irrigation and aeration drip system according to claim-9, characterized in that the drip has the flow of water controlled by the flow of air in a pressurized system to enable air and water movement even through small elevations along of the drip tube (14). Irrigation and aeration drip system according to claim 12, characterized in that a drip tube with an adjusted outlet pressure can be used on a water pressure differential regulator (36) by means of a reference air pressure produced in an air differential valve ( 38) in pressurized system. Irrigation and aeration drip system according to Claim 13, characterized in that it allows the connection of drip controllers (32) connected in series to the single drip tube, which feeds these water and air irrigation controllers by providing irrigation control according to with water tension in the ground. Irrigation and aeration drip system according to any one of claims 12 to 14, characterized in that it comprises the following steps: a) the air compressor (19) introduces controlled air flow through a restriction (9); water flow control differential valve (36) adjusts the pressure directly in the water inlet pipe (11) according to the gaseous pressurization acting on its reference c) the gaseous pressurization of the reference is applied using the restriction ( 39) receiving air at a differentially controlled pressure from the air pressure control differential valve (38) fed by the air compressor (19); d) the air pressure control differential valve (38) is also hermetically connected to the top of the pipe. water and air lift (12) for differential air pressure adjustment e) the total water pressure at the differential valve outlet (36) is equal to the pressure set on its inner spring a at the air pressure set on the air pressure control differential valve (38); f) used with an irrigation controller, drip closes when air accumulation in the drip controller chamber (32) causes the float (27) ) rest on the water outlet tube (29). Irrigation and aeration drip system according to any one of Claims 1 to 15, characterized in that it enables use in combination with a subsurface applicator. Irrigation and aeration drip system according to any one of claims 1 to 16, characterized in that the drippers may be arranged in a variety of arrangements including radial and panel arrangement.