|Title of Invention||
A CONTINUOUS MOVE CENTRE-PIOVT MOBILE IRRIGATOR
|Abstract||A center-pivot mobile irrigator to water a field, said mobile irrigator comprising: (a) stationary central pivot; (b) a movable segmented radial element extending radially away from said center pivot; (c) plurality of spraying elements supported on said radial element spaced along its length; (d) a plurality of wheeled tower frames for supporting said segmented radial element; (e) each of said tower frame having an independent drive means; and (f) controller means for controlling each of said drive means independently and synchronously to maintain collinearity of the various segments of said radial element.|
|Full Text||FORM - 2
THE PATENTS ACT, 1970
(39 of 1970)
THE PATENTS RULES, 2003
(Under section 10 and rule 13)
SOLAR POWERED, CONTINUOUS MOVE CENTRE-PIVOT MOBILE IRRIGATION SYSTEM.
MR. KELKAR PADMAKAR WAMAN
an Indian National
43/2, Erandwana, Off Karve Road, Pune - 411038
THE FOLLOWING SPECIFICATION DESCRIBES THE INVENTION.
Field of the Invention:
This invention relates to centre pivot mobile irrigation systems for farmlands.
Background of the Invention:
Irrigation is the artificial application of water to soil. In crop production it is not only used to replace missing rainfall in periods of drought, but also to protect plants against frost. Additionally, irrigation helps to suppress weed growing in rice fields. In contrast, agriculture that relies only on direct rainfall is sometimes referred to as dryland farming or as rainfed farming. The earliest method of irrigation as known through archeological surveys dates back to 6th century BC. Traces of canal were found which can be dated back to these times and are located in locations such as the Zana Valley of the Andes Mountains of Peru and the United States of America. The Indus Valley Civilization located in Pakistan and North India also had an extensive network of canals for practicing large scale agriculture. Flowing overground water such as rivers and streams can be directed to flow through canals. This kind of irrigation coupled with swelling of lakes due to annual flooding necessitated the need to build reservoirs and storage systems. This propelled the way towards sophisticated irrigation. The advent of pumps saw groundwater quickly being removed from aquifers and suitably used for specific purposes. Artificial storage of water through rains provided a substitute for drawing out underground water.
The water that is stored is finally distributed in fields. Various types of irrigation techniques differ in how the water obtained from the source is distributed within the field. The aim is to supply the entire field uniformly
with water such that each plant/portion of the field receives the appropriate volume of water without wastage.
Surface irrigation is a technique wherein, water flows over the land by simple gravity flow in order to wet it and to infiltrate into the soil. They can be subdivided into furrow, borderstrip or basin irrigation. Furrows and ridges form alternate crests and troughs of soil moulded to achieve those shapes in order to limit the exposure of soil to water. Basin irrigation provides for water-logging facility.
Localized irrigation is a system wherein, water is distributed under low pressure through a piped network, in a pre-determined pattern, and applied as a small discharge to each plant. This method includes drip irrigation, spray or micro-sprinkler irrigation and bubbler irrigation. Drip irrigation is a method of localized irrigation wherein, water is delivered at or near the root zone of plants. This type can be the most water-efficient method of irrigation, if managed properly, since evaporation and runoff are minimized. In sprinkler or overhead irrigation, water is piped to one or more central locations within the field and distributed by overhead high-pressure sprinklers or guns.
In recent years, centre pivot systems have come into widespread use as very effective means for irrigating farmland. A conventional centre pivot, mobile irrigation system includes a plurality of towers spaced apart and aligned in a row. Each tower comprises a frame having upper and lower portions. At the top or upper portion of each frame is a structure for supporting one end of an irrigation pipe section in a horizontal disposition and for coupling that pipe
section to another pipe section. The sections of irrigating pipe extend from one tower top to the next, for a total distance up to as much as one half mile. One end of the irrigation pipe is connected to a water source located adjacent a stationary or immobile pivot tower. The lower portion of each tower frame/carriage is connected to a pair of driven wheels. Each carriage is provided with a drive motor, preferably a 3 phase, 440 volts electric motor. Each of the mobile towers in conventional systems is of essentially identical construction, while the pivot tower is supported atop a concrete slab resting on its legs and is anchored in place on the concrete slab with chains, cables or the like, to prevent the pivot tower from moving while the rest of the irrigation system was rotating about the location of the stationary pivot tower.
Sprinklers are located at spaced intervals along the irrigation pipe. An electric cable for 440 volts, 3 phase electric power supply is laid along the pipe line and water or irrigation fluid supply from a water source like water pump entering the pipeline at the fixed tower/mast. Collector rings and electrical system control box are also provided to deliver power to the mobile irrigator. The motion of wheel mounted carriages causes the pipeline to revolve around the fixed tower/mast and the sprinklers sprinkling water to irrigate a large circular area within a field.
The movement of the towers is achieved as follows:
1. The last tower moves for a predetermined time depending upon the speed of operation, at full speed, and stops.
2. The sensor at the tower next to the last tower senses its position with respect to the last tower. If it finds that it is lagging behind by preset
angle (factory setting by mechanical fixture), the tower moves at full speed, and goes ahead, may be more ahead.
3. Similar action takes place at the tower next to the tower as described above,
4. Thus, the total movement of the Pivot takes place in a zigzag (snaky) action.
5. This movement may create more stresses on the components used for the structure.
6. There cannot be even distribution of water throughout the area.
7. Probability of the tower going out of limits and making the machine misaligned, ultimately stopping the same is quite high, as the towers always move with full speed.
8. High Power 3 Phase Motors are required to operate the machine.
9. High Voltage (440 Volts AC) is required to drive the machine, which requires very high safety constraints, as the machine is required to be operated in the fields, with rain, snow, water and heat.
10. As all the towers start and stop quite often, there is a great risk of slipping of tyre in the muddy conditions of the farm. Firstly, it is very difficult to detect this condition; the tyre gets worn out, thus reducing the efficiency, making the machine quite unreliable. If it goes unnoticed for a long time, water may be wasted.
11. Constant stopping and starting of the entire machine, also results in jerking motion of the entire configuration. This is relayed onto the trusses and joints of the machine, resulting in increased wear and tear of the machine.
There are several drawbacks or limitations of this mobile irrigator. The mobile irrigator known in the prior art requires high power 3 phase motors to operate the mobile irrigator and high voltage, (440 volts 3 phase AC) electric supply is required to operate each motor of the intermediate tower/wheel mounted carriages, which required very high safety constraints, as the mobile irrigator is used in open fields, thereby exposed to dust, rain, snow, humidity, storm and heat.
It is quite risky to lay the 440 volts electric wires/cables along the pipeline which is metallic as there are chances of electrocution and hazardous accidents, Further, it is essential to have collector rings/commutators to provide electric power supply to the mobile irrigator. The mobile irrigator moves continuously around the fixed tower/mast in a circle, throughout 360 degrees. The collector rings are the most vulnerable part, as there is sparking due to dust, corrosion due to humidity and other harsh atmospheric conditions, resulting into repeatedly break down and higher maintenance. Frequent start, stop operations of each intermediate tower puts lot of strain on all the mechanical and electrical components used in the mobile irrigator. Since each tower starts from zero speed there is a great problem of slipping of tyres of the carriages, particularly in the muddy conditions of the farm land, thus reducing the reliability and efficiency of the mobile irrigator. This also results into uneven water distribution/sprinkling and improper irrigation causing reduced yield of agricultural crops. Further, the mobile irrigator needing high voltage electric power supply cannot be used in remote areas where there is no electricity or the power supply is limited to single phase supply.
United States patent No. 6755362 describes an irrigation system for conveying a fluid from fluid source. The irrigation system may include several irrigator spans capable of reaching tens to hundreds of acres of the field, or the irrigation system may only include only a few irrigator spans capable of reaching only a few acres. The irrigator spans are moved about the center pivot tower by a drive system. Each irrigator span includes its own drive system for moving the span radially about the center pivot tower. A first drive system moves the first irrigator span. A second irrigator span extends from the distal end of the first irrigator span and a second drive system moves the second irrigator span. A potentiometer which is used in combination with an alignment bar and an actuator operates as an alignment mechanism which interconnects the first irrigator span and the second irrigator span to maintain alignment between the first irrigator span and the second irrigator span within a predetermined limit. The system is characterized by one of the drive systems being variable speed and the alignment mechanism including a potentiometer for measuring the magnitude of misalignment between the first and second irrigation spans for varying the speed of one of the drive systems. The speed of one of the drive systems is varied to realign the first irrigator span and the second irrigator span to maintain the predetermined limit.
United States patent No. 6254018 describes a system for an alignment control for long centre pivot systems having an elongated water pipe extending outwardly from a center pivot structure with the water pipe being supported upon a plurality of drive units which propel the water pipe around the centre pivot structure. Each of the drive units includes a drive means such as an electric motor which is actuated by a mechanical linkage at each
drive unit span joint, which operates a micro-switch, which in turn starts and stops the electric motor on the drive unit to keep it in line with the next span. A first GPS control is provided at the centre pivot structure which functions as a stationary reference. A second GPS control is positioned on the centre drive unit near the centre length of the water pipe. A third GPS control is mounted on the outermost or last drive unit. A computer-operated control system is operatively connected to the centre drive unit where the second GPS control is located. The first, second and third GPS controls are operatively connected to the computer-operated control system. The computer-operated control system computes an approximate straight line between the centre pivot structure and the last drive unit and selectively operates the drive means on the centre drive unit so that the centre drive unit will be positioned or maintained within some tolerance of the approximate straight line between the centre pivot structure and the last drive unit. The computer-operated control system may continuously compute the approximate straight line or periodically compute the approximate straight line. As stated, the centre drive unit includes an alignment control which normally controls the movement of the centre drive unit. The computer-operated control system may override the alignment control on the centre drive unit when the position of the centre drive unit exceeds some tolerance from the approximate straight line. The irrigation system may further include a system control for stopping all of the drive units when the last drive unit has reached the predetermined position. The irrigation system may further include a system control for reversing the direction of the irrigation system when the last drive unit has reached a predetermined position in the field. Further, the irrigation system may include a selectively operable end gun sprinkler at the outer end of the water pipe which is actuated when the last
drive unit reaches a predetermined position in the field and which deactuates the end gun sprinkler when the last drive unit has reached a particular position in the field.
United States patent No. 5613641 describes a hydraulic control apparatus for hydraulically powered center pivot irrigation systems which utilizes dual-spool, four-way hydraulic valves for controlling the movement of inner support towers, and a pressure controlled directional valve with a dedicated high pressure line to control the direction and speed of the outer tower and hence of the entire system. One of the spools controls the clockwise movement of the irrigation system, while the second spool controls system movement in the counter clockwise direction. Should an inner support tower malfunction and fail to move, the outer sections can be driven back into realignment by simply reversing the hydraulic pressure in the two primary lines.
United States patent No. 5255857 describes a device to maintain the alignment of two articulated elongate members, particularly adjacent spans of a mobile irrigator or pivot, there being a flexible joint between the spans, connecting them together and having freedom of rotation about the x- and y-axis and limited freedom to rotate about the z-axis, the joint including a sensor device for sensing movement and converting same to electrical energy for feeding to a computer for correcting alignment. The sensor may be a Hall Effect device or an optical sensor device.
United States patent No. 4580731 describes a control apparatus for use in an irrigation system having a plurality of conduit sections pivotally joined at
sets of adjacent ends and selectively operable drivers for moving the conduit sections in a forward direction. Each control apparatus maintains the relative alignment of a pair of joined conduit sections. It includes a conduit misalignment indicator having two indicating portions which are directly relatable in position to the relative alignment of the two conduit sections. Further, Hall-effect sensors positioned on one indicating portion opposite from a magnet positioned on the other indicating portion provide for sensing of the relative alignment of the conduit sections. A digital electrical circuit converts the sensor signals into a control signal for initiating operation of the driver when the conduit sections are in lagging misalignment and terminating operation when the conduit sections are in leading misalignment. The apparatus may be used with a direction indicator to initiate operation of the driver when the conduit misalignment exists for the given direction of travel. Also, the two indicating portions may be disposed on a misalignment multiplier which increases the sensitivity of the apparatus to the relative alignment of the two associated conduit sections.
The above mentioned patents of the prior art work on the principle of aligning the misaligned structural members, thus causing snaky/zigzag motion. This motion stresses the said structural members and thus results in its wear and tear. As a result, there is a need in the art for an irrigation system to overcome the problems and limitations of the prior art.
Objectives of the Invention:
One object of this invention is to uniformly water a field.
Another object of this invention is to uniformly water any given field.
Yet another object of this invention is to provide a continuous irrigation system.
Still another object of this invention is to prevent misalignment of segments of arm of centre-pivot mobile irrigator.
Still another object of this invention is to provide real-time instantaneous correction to prevent misalignment.
An additional object of this invention is to overcome the snaky zigzag movement of the system of the prior art.
Still, an additional object of this invention is to power the system using natural resources.
Summary of the Invention:
A centre-pivot irrigation system in accordance with this invention envisages a continuous moving mobile irrigator maintaining a substantially linear configuration at all times. Constant move for the centre-pivot irrigation system greatly improves the uniformity of water distribution, thus increasing the agricultural output. As all the towers are moving constantly almost all the times, the problem of slipping of tyre in the mud is greatly reduced, increasing the overall efficiency of the operating system, because the tower is not required to start and stop all the time and every time.
According to one embodiment of this invention there is provided a centre-pivot mobile irrigator to water a field comprising: (a) a stationary central pivot;
(b)a movable element extending radially from said centre pivot; (c) said radial element supporting a plurality of spraying elements spaced
along its length; (d)said radial element having a plurality of segments joined end to end to form said radial element adapted to articulate with respect to each other to move collinearly along a substantially arcuate path;
(e) each segment having a proximal and a distal end;
(f) the distal end of a first segment being connected to the proximal end of another to form an articulated flexible joint;
(g)a wheeled frame for supporting said segment and adapted to move at a controlled speed proportional to the speed of the outermost wheeled tower frame to maintain collinearity;
(h)one member of the set of the wheeled tower frames at the distal end of the outermost segment and the remaining members of the set around said articulate joints;
(i) drives for driving each said wheeled tower frame/element of the set;
(j) control elements for controlling each of said drives;
(k) control element for the drive of the outermost wheeled tower frame adapted to provide feedback signals to the control element associated with the penultimate intermediate wheeled tower frames;
(1) said control element of the penultimate intermediate wheeled tower frame adapted to provide feedback signals to the control element associated with the previous intermediate wheeled tower frame; and
(m) a central control element adapted to control the angular displacement of the outermost drive and in turn provide control and speed signals to the controller of the other drives to prevent misalignment of said segments of said radial element from its operative linear configuration.
According to another embodiment of this invention, the end wheeled tower frame is provided with a feedback from its drive to its control element to maintain the desired speed.
According to another embodiment of this invention, each control element of a wheeled tower frame is adapted to provide feedback to a control element of a previous wheeled tower frame to provide corrective actions in case of misalignment.
According to yet another embodiment of this invention, flow of water is facilitated through said radial element from its proximal end to its distal end.
According to yet another embodiment of this invention, a pump draws water and relays it to said radial element though a vertical pipe at said centre-pivot.
According to yet another embodiment of this invention, said vertical pipe at said centre-pivot is provided with a bearing with coupler to facilitate the rotation of pipe in a complete 360 degree revolution.
According to still another embodiment of this invention, there are provided flexible couplings at each articulated joints such that they connect the distal
end of one segment with the proximal end of another segment, thus allowing some degree of motion at said articulated joints.
According to still another embodiment of this invention, there is provided a flow controller element to regulate the flow of water.
According to another embodiment of this invention, said water flow is proportional to the speed of said mobile irrigator.
According to an additional embodiment of this invention, said drive for driving each wheeled tower frame comprises a bi-directional DC motor.
According to yet an additional embodiment of this invention, said wheeled tower frame comprises a pair of wheels; an operative front wheel and an operative back wheel, axles of said front and back wheels are aligned in a radially outward direction with respect to said centre-pivot.
According to still an additional embodiment of this invention, said drives are driven by atleast one power source selected from a group consisting of electricity/solar/alternating current/direct current/gas/tractor/solid/fuel/liquid fuel/mixed fuel.
According to yet another embodiment of this invention, said central control element provides speed signal to said end wheel tower frame and said intermediate wheeled tower frames.
According to still another embodiment of this invention, said control elements of intermediate wheeled tower frames provide speed signals to their respective drives which are fractions of speed of said end wheeled tower frame.
According to .still another embodiment of this invention, a sensor is provided at each said articulated joint which works in conjunction with its respective control element. Each sensor has a first threshold parameter and a second threshold parameter. If both threshold parameters are violated, the machine stops. If the first threshold parameter is breached, a misalignment signal is generated and relayed to a previous wheeled tower frame placed in the direction towards the centre-pivot. Thus, corrective measures can be applied to the corresponding wheeled tower frames to maintain a substantially linear configuration. A slip-timer also works in conjunction with the sensor and corrective assembly. If no corrective action is applied for a preset time according to said slip-timer, the mobile irrigator stops. This is important in cases of slipping in mud, uneven terrain or the like unusual circumstances.
According to another embodiment of this invention, said central control element is governed by user-defined programmable parameters such as speed of rotation, direction of motion, mode of operation and the like control parameters.
According to another embodiment of this invention, said central control element is governed by manual switches such as starting clockwise motion, starting counter-clockwise motion, starting end-gun spray, and the like
modes of operation. This also includes manual re-alignment in case the system is misaligned.
According to an additional embodiment of this invention, said control element of wheeled tower frame comprises:
(a) a micro-controller with embedded software adapted to calculate the
desired speed with respect to input parameters and as a fraction of end
wheeled tower frame; (b)said micro-controller adapted to calculate and relay its speed
parameters to another micro-controller of a previous wheeled tower
frame to prevent misalignment between said segments of said radial
arm; (c) a sensor assembly calibrated to assess the movement with respect to
next tower in the outward direction toward the end wheeled tower
frame and relay the same to said micro-controller to provide a
commensurate electrical signal; (d)a manual calibration assembly adapted to input the number of towers
in said mobile irrigation system;
(e) a motor drive adapted to receive inputs from said micro-controller;
(f) a motor driven by said motor drive; and
(g)a power supply assembly adapted to drive each of the said assembly of said tower controller.
According to yet another embodiment of this invention, said centrally located control element comprises:
(a) a micro-controller with embedded software adapted to:
i. receive parameters such as temperature, direction of motion, start, stop, refresh, rate of motion, rate of flow, timing for activation and de-activation of slip-timer, nature of field, distance for clockwise movement, distance for counter-clockwise movement and the like user-defined functions; and ii. transmit parameters for controlling each said intermediate control element and said end control element to prevent misalignment; (b)an alpha-numeric display to display the parameters of said microcontroller; and (c) a LED display adapted to display the selected operations;
According to still another embodiment of this invention, a last arm extends out of the articulated joint supported by end wheeled tower frame. Distal end of the last arm is provided with an end-spray gun. Said last arm can also be a retractable arm adapted to retract into and out of said radial element to cover irregularly shaped fields.
According to another embodiment of this invention, said power source is a hybrid power source comprising:
(a) solar panels adapted to absorb solar energy;
(b)a charge controller adapted to work in conjunction with said solar
panel to control the flow of energy being relayed to a battery; (c)a step down isolation transformer adapted to reduce the voltage
received from an alternating current source; (d)a rectifier filter adapted to convert alternating current source into a direct current output;
(e) a switch adapted to select said solar power source or said alternating current source; and
(f) a battery bank adapted to store energy before relaying it to said wheeled tower frames.
According to another embodiment of this invention, said control elements are connected to each other through a two-wire signal loop.
According to an additional embodiment of this invention, said articulated joint has freedom of rotation about the x-axis and the y-axis.
Brief Description of the accompanying Drawings:
The invention will now be described in accordance with the accompanying drawings in which:
Figure 1 illustrates a front view of the centre-pivot mobile irrigation system alongwith its electrical systems;
Figure 2 illustrates the electrical wiring and signaling diagram for a centre-pivot mobile irrigation system;
Figure 3 illustrates a front view of the centre-pivot mobile irrigation system along with its sprinkling system;
Figure 4A illustrates a front view of the radially extending element between two wheeled frames along with its supporting truss assembly;
Figure 4B illustrates an auxiliary view of the radially extending element between two wheeled frames along with its supporting truss assembly;
Figures 5 A and 5B illustrate a flexible coupler fitted over segments of pipe located at an articulated joint of a centre-pivot mobile irrigator;
Figure 6 illustrates a front profile and a side profile of a wheeled tower frame of the centre-pivot mobile irrigator system;
Figure 7 illustrates a plan view of the mobile irrigation system including the area under cultivation covered by it;
Figure 8 illustrates a plan view of a centre-pivot mobile irrigator system adapted to irrigate a semi-circular field;
Figure 9 illustrates a block diagram of a hybrid power source for a centre-pivot mobile irrigation system;
Figure 10 illustrates a block diagram for a logic control element mounted on the centre pivot of a centre-pivot mobile irrigation system;
Figure 11 illustrates a block diagram for a standard tower control element mounted on each of the towers of a centre-pivot mobile irrigation system; and
Figure 12 illustrates a block diagram for a logic system of a centre-pivot mobile irrigation system in accordance with this invention.
Detailed Description of the accompanying Drawings:
Figure 1 illustrates a front view (300) of the mobile .irrigation system in accordance with this invention alongwith its electrical systems. A centrally located pivot (10) is attached to a radially extending element (12). This element (12) is built of a plurality of segments (14) articulated by joints (16). The joints (16) are supported by wheeled tower frames (18, 20 22). A set of wheeled tower frames comprises a plurality of standard intermediate wheeled tower frames (18, 20, 22) and one end wheeled tower frame (24). All the wheeled tower frames (18, 20, 22, 24) include a control element (26, 30, 32, 34) calibrated and adapted to calculate the speeds of the corresponding wheeled tower frames (18, 20, 22) with respect to the end wheeled tower frame (24). Another control element (36) located at the centre pivot (10) provides input signals and DC power (90) to each of the wheeled tower frames (18, 20, 22, 24). A sensor (27) is located at each of the joints (16). A two wire current loop (28) provides the electrical connections between the control elements (26, 30, 32, 34) of the wheeled tower frames (18, 20, 22, 24). A centrally located logic control element (36) provides signals to the control element (26, 30, 32) of each of the standard intermediate wheeled tower frames (18, 20, 22) and to the control element (34) of the outermost wheeled tower frame (24). Each wheeled tower frame provides feedback signals to the previous wheeled tower frame. The end wheeled tower frame (24) is provided with a feedback assembly (72) from its motor to its control element (34). This feedback assembly (72) measures and maintains the required speed of the end wheel. The intermediate wheeled tower frames (18, 20, 22) pre-calculate their respective speeds in relation to the end tower frame (24).
A sensor (26) is provided at each of the articulated joints (16) of the mobile irrigator, which works in conjunction with the control element (26, 30, 32) of the respective wheeled tower frame (18, 20, 22). The sensor senses the misalignment outside of its threshold value, and relays a signal in relation to the misalignment to its previous control element towards the centre-pivot. Thus, the previous control element takes note of this misalignment and alters its speed to maintain a substantially linear alignment. Thus, the feedback assembly provides for compensatory adjustments in the respective speeds in relation to the next wheeled tower frame towards the end tower frame to maintain a substantially linear alignment. This system and method prevents misalignment of the segments and the wheeled tower frames.
Figure 2 illustrates the electrical wiring diagram for a mobile irrigation system in accordance with this invention.
The mobile irrigator in accordance with this invention is driven by a hybrid power source. One of the sources it derives its energy from is the solar power source. Solar panels (50) in conjunction with a charge controller (52) generate energy which is stored in a battery bank (54). It powers a logic control element (56) located at the central pivot and also the other control elements (26, 30, 32, 34) and motors (88, 86, 84, 70) at the wheeled tower frames via DC power lines (90). Speed signal is supplied from the centrally located logic control element (56) to each of the intermediate standard tower control elements (26, 30, 32) and to the end tower control element (34). The logic control element (56) receives user-defined programmable parameters such as speed of rotation, flow of water, direction of motion and the like. The logic control element is also governed by switches such as the pressure
switch (60), endgun water spraying switch (62), clockwise limiting switch (64), and the counter-clockwise limiting switch (66). The logic control element (56) of the central pivot drives each of the tower control elements (26, 30, 32, 34) and provides speed signal to each of the intermediate towers. The end tower control element (34) receives the input parameters as defined by the user in relation to speed. The speed signals are transmitted by a two wire 0-20 mA or 4-20 mA system. The current in the series system remains constant and thus same signal is delivered to all the standard intermediate tower control elements and to the end tower control element. The signal does not change with the length of the cable. This is a fail safe type of system. If one line or point is disconnected, the total system will come to halt, rather than operating in an odd manner. The end tower control element (34) drives a bi-directional motor (70) connected to the end tower and receives feedback from it (72). The control elements at the intermediate wheeled tower frames pre-calculate the desired speeds as a fraction of the speed of the end wheeled tower frame.
Sensors at joints sense the misalignment between segments and signals in relation to misalignment (82) are transmitted in feedback form from a standard intermediate control element to a previous standard intermediate control element i.e. from the distal end to the proximal end. Each of the intermediate standard control elements (26, 30, 32) drive their respective motors (88, 86, 84) and consequently the respective wheeled tower frames.
Figure 3 illustrates an irrigating assembly of the centre-pivot mobile irrigation system in accordance with this invention.
A centrally located pivot (10) comprises a water inlet means (102) into which water drawn from a pump is relayed. Segments of pipe (12) facilitate
the flow of water from the centre pivot (10) to the distal end of the system. A bearing with coupler (106) is provided at the centre pivot (10) to facilitate the rotation of the pipe (12) in a complete 360 degrees revolution. Flexible couplings (114) are provided at the articulated joints supported by wheeled tower frames (18, 20, 22, 24). These couplings (114) provide for some amount of degree of freedom such that the segments of pipe at the articulated joint have a tolerable liberty of motion before they are linearly aligned in cases of misalignment and also to allow uninterrupted flow of water through the articulated joints. Flow of water (108) is from the proximal end to the distal end of the mobile irrigator system. Sprinklers (110) are placed throughout the length of the pipe (104), spaced apart from each other to provide uniform irrigation. An end corner gun (112) is provided at the farthest end to cover areas outside of a circular field. The discharge of a sprinkler (110) and the distance between two sprinklers (110) is selected such that there is even distribution of water. Thus, the farthest sprinkler has the highest discharge, as it has to cover maximum area.
Figure 4A illustrates a front view of the radially extending element between two wheeled tower frames along with its supporting truss assembly. Figure 4B illustrates an auxiliary view of the radially extending element between two wheeled tower frames along with its supporting truss assembly. The distal end of one segment of pipe (116) is screwed to the proximal end of another segment of pipe (117) through its flanged ends (118). An assembly of trusses (119) supports these segments of pipes (116, 117). The truss members between two wheeled tower frames have a proximal end which is free and a distal end which is connected to a wheeled tower frame. A flexible coupler (114) at the articulated joint (16) provides some degree of
motion and an interrupted flow between the rigid segments of pipe located on either end of said articulated joint (16).
Figures 5A and 5B illustrate a flexible coupler (114) fitted over segments of pipe at an articulated joint to provide a connection between the distal end of one segment of pipe and the proximal end of another segment of pipe. The distal end of the first segment (14) is provided with a male part (17) which engages with the female part (19) located at the proximal end of the second segment (15). This forms a secure aligned connection. The flexible coupler slides over these two segments at the respective distal and proximal ends. An L-shaped plate (21) slides in between the pipe (14) and the flexible coupling (114) to ensure a firm leak-proof assembly.
Figure 6A illustrates a front profile of a wheeled tower frame of the centre-pivot mobile irrigator in accordance with this invention. Figure 6B illustrates the side profile of a wheeled tower frame of the centre-pivot mobile irrigator in accordance with this invention.
A pair of wheels (120) is driven by a geared, low voltage permanent magnet DC motor (122). The wheels are connected to an articulated joint (124) through a supporting structure (126, 128) for the said joint (124). The supporting structure (126, 128), the joint (124), the tyres (120, and the DC motor (122) form the wheeled tower frame.
Figure 7 illustrates a plan view of the mobile irrigation system in accordance with this invention including the area under cultivation covered by it. A centrally located pivot point (10) is the centre of a circle being defined by
the centre-pivot irrigation system in accordance with this invention, the radius of this circle being the length of the radially extending element (140). Areas of the field outside the circumference of the circle as shown by the reference alphabets A, B C, and D, will be irrigated by an end gun (112) placed at the farthest tip of the radial element (140).
Figure 8 illustrates a plan view of a mobile irrigator system in accordance with this invention adapted to irrigate a semi-circular field. The pivot point (10) is located on the diametrical edge of the semi-circular field. The irrigator in accordance with this invention is adapted to move in both clockwise and counter-clockwise direction. One end of the semi-circular field includes a first barricade (160) to operate a switch which limits the clockwise motion of the irrigator, and the irrigator reverses its direction of motion. A diametrically opposite end of the semi-circular field includes a second barricade (162) to operate a switch which limits the counterclockwise motion of the irrigator, and the irrigator reverses its direction of motion. The automatic reversal of modes of the mobile irrigator takes place only if the auto-reverse mode of the system is activated.
Figure 9 illustrates a block diagram of a hybrid power source for a centre-pivot mobile irrigator.
A first power source is by way of solar energy. Solar panels (50) absorb solar energy. A charge controller (52) controls the amount of charge and works in conjunction with said solar panels (50) to produce power. This power is stored in a battery bank (54) before it is relayed to the necessary assemblies. When there is sun and the photo-voltec voltage is more than the battery voltage, the charge controller (52) starts delivering the charge to the
battery bank (54). If the battery voltage rises above the set overcharge voltage, the charge controller cuts off the charging of the battery (54), thus protecting the battery (54). When the photo-voltec voltage goes lower than the battery voltage, the charge controller (52) cuts off charging and thus avoids the heating of the solar panels. Basically, the solar power is a constant current source and there is no problem of short circuit of solar panels.
An alternate power source is an alternating current source. A step-down isolation transformer (170) reduces the voltage being supplied from the mains (172). A rectifier filter connected with the transformer (170) converts the alternating current into direct current before being relayed to the necessary assemblies.
A switch (176) selects the power source from the solar power source and the electric power source.
Figure 10 illustrates a block diagram for a logic control element mounted on the centre pivot of a centre-pivot mobile irrigation system in accordance with this invention.
The logic control element comprises a manual input means, a programmable input means, a processing means, an output means, a display means, a synchronisation means and a storage means.
Said processing means comprises a micro-controller (190) with embedded software. Manual input parameters include speed of operation (192), start (200), stop (194), clockwise mode of operation (196), counter-clockwise mode of operation (198), keyboard (202) for entering and programming additional user-defined functions, arrow keys (204) for selecting preprogrammed functions, misalignment threshold parameters (206), water flow
rate (208), temperature (210), auto-reverse functionalities (212), auto-restart functionalities (214), limits for clockwise movement (216), limits for counter clockwise movement (218) and the like features. The microcontroller is supported by a non-volatile random access memory (220) for storage of input and output parameters and a real time clock (222) for autostart and auto-stop features of the mobile irrigator system. The output of the micro-controller (190) is visible on an alpha-numeric display (224) and also on a LED (Light Emitting Diode) indicator (226). The LED indicator (226) is adapted to display whether the irrigator is operating in the clockwise direction (228), whether the irrigator is operating in the counter-clockwise direction (230), an alarm (232) incase misalignment over the acceptable threshold value takes place, and a stop indicator (234) to display if the irrigator is at rest. Signals from the micro-controller (190) are in digital format and are converted to analog signals by the digital to analog converter (236). The analog signals are fed to a voltage to current converter (238) from which it is relayed through a two-wire current loop (28). A separate assembly (240) provides power to all the blocks of the logic control element. During its first installation or in cases of misalignment before starting the centre-pivot mobile irrigator, a manual alignment needs to be carried out. The control element at the centre pivot is provided with a manual clockwise operation switch and a manual counterclockwise operation switch. If, upon installation, the segments of the radial arm have formed a snaky zigzag pattern, then the manual clockwise/counterclockwise switch is operated. The selection of the switch depends on the direction that the end tower controller needs to move such that it aligns with the penultimate tower. The switch is kept pressed at all times. Once the end tower aligns with the penultimate tower, both towers now start moving in a linear configuration. As soon as
the operator sees this, he chooses the direction of motion to operate the manual switch such that the penultimate tower alongwith the end tower is aligned with the tower previous to the penultimate tower. This procedure continues until all the towers are in a substantially linear disposition.
Figure 11 illustrates a block diagram for a standard tower control element mounted on each of the towers of a centre-pivot mobile irrigation system in accordance with this invention.
The standard tower control element located at each of the wheeled tower frames comprises a processing means, an input means, and an output means. Processing means includes a micro-controller (250) with embedded software. Input parameters include settings for the number of towers (252) and the position of towers (252). A sensor linkage system (254) links the sensor assemblies of one tower with its next operative and previous operative tower. The microcontroller calculates the speed of its corresponding tower in relation to the end tower to prevent misalignment. The sensor system (256) receives feedback from the next operative tower and in conjunction with its corresponding sensor system, provides a corrective action to maintain a substantially linear position at all times. A current source (258) relays current to a current to voltage converter (260). Output from the current to voltage converter (260) is relayed to an analog to digital converter (262) to be fed to the micro-controller (250). The microcontroller (250) computes the necessary parameters and transmits the same to drive a geared DC motor (264) via a digital to analog converter (266) and via a DC motor drive (268) with current limit and dynamic breaking option. A separate assembly (270) provides power to all the block of the logic control element.
Each sensor has a first cut-off threshold parameter and a second threshold cut-off parameter. Total misalignment occurs when the second threshold cutoff parameter has been breached. Partial misalignment occurs when only the first threshold cut-off has been breached. This provides for corrective action based on feedback from the next tower and adequate speed signals to the tower under consideration. To prevent total misalignment, each control element is also provided with a slip-timer. This timer is pre-set such that if the first threshold cut-off has been breached and no curative measure has taken place within the set period of time, the machine stops. This prevents the irrigator to advance into a further misaligned configuration.
Figure 12 illustrates a block diagram for a logic system of a centre-pivot mobile irrigation system in accordance with this invention. A logic control element (30) receives a preset user-defined time and speed setting. The logic control element (30) is governed by control parameters such as manual switches; right hand limit switch (282) and the left hand limit switch (284) to control the movement in clockwise or counterclockwise directions. The logic control element (30) provides inputs in relation to desired speed (288) of motion to each of the intermediate control elements (26, 30, 286) and the end tower control element (34). The end tower control element drives its motor and receives feedback (72) from the motor regarding the actual speed of the end tower. This feedback mechanism (72) helps maintain the desired speed at all times. Each of the intermediate tower control elements (26, 20, 286) drive their motors at speeds with are fractions of the end tower speed. Each tower control element provides feedback to its previous tower control element. A misalignment signal (82)
is generated if there is any misalignment between the two sides of an articulated joint as sensed by its respective sensor. The control element takes note of the misalignment signal and powers-up or powers-down the associated DC motor to maintain an approximately linear configuration of the entire mobile irrigation system in accordance with this invention. All the control elements are driven by a hybrid power source (312).
Exemplary embodiments of computations with respect to speed of motion
and distance travelled are explained as follows:
1) Calculations with respect to speed are described below:
Assume a centre-pivot mobile irrigator with 3 intermediate standard control
elements and 1 end tower control element.
Let the end tower (tower4) speed be SI.
Let Tower3 be the tower nearest to the end tower (tower4).
Assuming that the towers are equidistant from each other and that the distance of tower 3 from the centre pivot is equal to the spaced apart distance of the equidistant towers,
Speed of Tower 3 = Six
Total _ Number _of _ Towers
= 75% of Speed of End Tower (Tower4).
Similarly for the remaining intermediate towers,
Speed of Tower 2 = S1 x 2/4 = 50% of Speed of End Tower (Tower4).
Speed of Tower 1 = S1 x 1/4 = 25% of Speed of End Tower (Tower4).
If End Tower (Tower4) speed is set at say 1000 rpm or linear speed of End
Tower (Tower4) is 4 feet/minute,
1st Tower will move at 750 rpm or 3 feet/minute;
2nd Tower will move at 500 rpm or 2 feet/minute;
3rd Tower will move at 250 rpm or 1 feet/minute.
2) Calculations with respect to distance are described below: Assuming that the centre-pivot mobile irrigator in accordance with this invention completes 1 revolution per hour, it can be inferred that the end tower completes one complete revolution about the centre-pivot. Let the centre-pivot mobile irrigator have 3 intermediated standard towers (tower l, tower 2, and tower 3) and 1 end tower (tower4).
Let the distance between tower4 and centre-pivot be 100 metres. Distance travelled by tower4 (i.e. circumference) = 2(pi)100= 628 metres. Therefore, speed of travel is 628 metres per hour.
Let the distance between tower 3 and centre-pivot be 75 metres. Distance travelled by tower 3 (i.e. circumference) = 2(pi)75= 471 metres. Therefore, speed of travel is 471 metres per hour, which is equal to 75% of speed of tower4.
Let the distance between tower 2 and centre-pivot be 50 metres. Distance travelled by tower 2 (i.e. circumference) = 2(pi)50= 314 metres. Therefore, speed of travel is 314 metres per hour, which is equal to 50% of speed of tower4.
Let the distance between tower l and centre-pivot be 25 metres. Distance travelled by tower l (i.e. circumference) = 2(pi)25= 157 metres. Therefore, speed of travel is 157 metres per hour, which is equal to 25% of speed of tower4.
Typically, the sensor in accordance with this invention operates within 4.5 degrees in both the clockwise and counter-clockwise directions. The total allowable span is 9 degrees on both the clockwise and counter-clockwise directions, after which the machine is misaligned.
In view of the wide variety of embodiments to which the principles of the present invention can be applied, it should be understood that the illustrated embodiments are exemplary only. The illustrated embodiments should not be taken as limiting the scope of the present invention. For example, the interactions between the components may be taken in sequences other than those described, and more or fewer elements may be used. While various elements of the preferred embodiments have been described as being implemented, other embodiments implementations may alternatively be used, and vice-versa.
Dated this 18th day of June 2007
|Indian Patent Application Number||1175/MUM/2007|
|PG Journal Number||33/2012|
|Date of Filing||18-Jun-2007|
|Name of Patentee||KELKAR PADMAKAR WAMAN|
|Applicant Address||43/2, ERANDWANA, OFF KARVE ROAD, PUNE-411 038,|
|PCT International Classification Number||F16K1/14,F16K31/524|
|PCT International Application Number||N/A|
|PCT International Filing date|