WO2000049373A1

WO2000049373A1 - Water meter

Info

Publication number: WO2000049373A1
Application number: PCT/IL1999/000106
Authority: WO
Inventors: Moshe Fisher
Original assignee: Moshe Fisher
Priority date: 1999-02-18
Filing date: 1999-02-18
Publication date: 2000-08-24
Also published as: IL138960A0

Abstract

Apparatus for controlling a volume of liquid from a controllable source of liquid dispensed by a liquid-dispensing system having at least one liquid dispenser that dispenses liquid at a first flow rate, the apparatus comprising: a liquid outlet through which the liquid flows at a second flow rate from the controllable source; and a volume sensor that provides a signal responsive to a volume of liquid dispensed by the liquid outlet; wherein the controllable source of liquid is turned off when a volume of liquid dispensed by said liquid outlet reaches a given volume.

Description

WATER METER FIELD OF THE INVENTION

The invention relates to metering water and in particular to controlling amounts of water used for agricultural and domestic irrigation of plants. BACKGROUND OF THE INVENTION

In our densely populated industrialized world provision of water for domestic, industrial and agricultural use has become a major concern and commercial activity. Clean water cannot be taken for granted and in efforts to supply water of appropriate quality for human use, water is mined, stored, bottled, treated, purified and transported over large distances. Water has become an expensive commodity that must be husbanded and conserved and is a commodity that will almost certainly become more expensive as world population and level of activity increase.

Agriculture in particular is a water intensive industry that consumes a major portion of the world's water resources. Significant effort is continuously being invested to improve the efficiency with which water is used in home and industrial agriculture. Plant irrigation systems comprising various methods and devices for dispensing water to plants in controlled amounts and at controlled times have been developed for optimizing plant irrigation in home gardens, hothouses, public gardens, crop fields and orchards.

Generally, a plant irrigation system comprises a pump that supplies water to a manifold to which a plurality of water dispensing devices, hereinafter referred to as "water dispensers", such as sprinklers, sprayers or drippers is connected. Each water-dispenser may supply water to a single plant or a few plants, such as a tree or a few trees in an orchard, or to a limited region of a lawn, garden, or crop field. The amount of water that a plant or planted region receives from a water-dispenser in the irrigation system is controlled by turning the pump on and off. The pump in turn is often controlled by timers or may be controlled responsive to output signals from various sensors such as temperature sensing devices, lysimeters, or sensors that determine soil-water content or evaporation rates.

Research and development aimed at providing methods and devices for controlling how much water an irrigation system provides plants is ongoing and there is a market for new and simple devices for controlling irrigation systems.

SUMMARY OF THE INVENTION An aspect of some preferred embodiments of the present invention relates to providing an irrigation system that delivers controlled quantities of water to plants. According to an aspect of some preferred embodiments of the present invention the irrigation system delivers a predetermined quantity of water to each plant or planted region irrigated by the irrigation system. In some preferred embodiments of the present invention the predetermined quantity of water is the same for all plants or planted regions irrigated by the irrigation system. In some preferred embodiments of the present invention the predetermined quantity of water is different for at least two plants or planted regions irrigated by the irrigation system.

An aspect of some preferred embodiments of the present invention relates to providing an apparatus, hereinafter referred to as a "water monitor", for controlling amounts of water provided to a plant or to a planted region by an irrigation system.

According to an aspect of some preferred embodiments of the present invention, the water monitor comprises a receptacle for receiving water and at least one sensor, hereinafter referred to as a "volume sensor", for sensing the volume of water in the receptacle. The at least one volume sensor provides an output signal responsive to a volume of water that it senses. According to an aspect of some preferred embodiments of the present invention, during times that the irrigation system is operating, water flows into the receptacle at a rate that is known relative to a rate at which the irrigation system delivers water to irrigate plants.

According to an aspect of some preferred embodiments of the present invention, flow of water in the irrigation system is controlled responsive to the volume of water in the receptacle that is sensed by the at least one volume sensor.

An aspect of some preferred embodiments of the present invention relates to controlling the amount of water dispensed by each water-dispenser of an irrigation system comprising a manifold to which a plurality of water dispensers is connected.

An irrigation system in accordance with a preferred embodiment of the present invention comprises a plurality of preferably identical water dispensers connected to a manifold and a suitable valve or water pump that controls whether water is supplied or not supplied to the manifold. The irrigation system comprises a water monitor in accordance with a preferred embodiment of the present invention. Preferably, one of the dispensers, hereinafter referred to as a "monitoring dispenser", is coupled to the water monitor so that all water that flows out of the manifold through the monitoring dispenser flows into the receptacle of the water momtor. Therefore, when the irrigation system is operating, the rate at which water fills the receptacle is substantially equal to the rate at which each water-dispenser of the irrigation system delivers water to a plant or a planted region being irrigated by the irrigation system. The pump or valve is preferably controllable to be turned off responsive to a signal generated by the volume sensor of the water monitor when a volume of water in the receptacle is equal to a predetermined volume of water.

For simplicity of presentation it is assumed hereinafter that a water pump controls water flow to the manifold and that each water-dispenser delivers water to a single plant.

In accordance with a preferred embodiment of the present invention, the irrigation system is controllable to provide an irrigation cycle during which each plant irrigated by a water-dispenser of the irrigation system receives a same desired volume of water.

An irrigation cycle begins when the pump is turned on to provide water to the manifold and ends when the pump is turned off by a signal from the water monitor. Prior to the beginning of the irrigation cycle the receptacle contains a first volume, which may be equal to zero, of water. The water monitor is set or calibrated to provide a signal to shut off the pump when the volume of water in the receptacle is equal to a second volume of water. The difference between the first and second volumes of water is known and equal to the desired volume of water that is to be delivered to a plant by a water-dispenser of the irrigation system.

At the beginning of an irrigation cycle, when the pump is turned on, water from the manifold flows out the water dispensers to irrigate plants. Water from the manifold flows out the monitoring dispenser and fills the receptacle. When a signal from the volume sensor indicates that the volume of water in the receptacle has increased to the second volume of water the signal from the volume sensor turns off the pump. As a result, the pump is on and water flows into the manifold only for a period of time that it takes water that flows through the monitoring dispenser to fill the receptacle with the desired quantity of water. To the extent that all water dispensers connected to the manifold dispense water at a rate equal to the rate at which the monitoring dispenser dispenses water, each plant irrigated by a water-dispenser receives the desired amount of water.

There is therefore provided, in accordance with a preferred embodiment of the present invention, an apparatus for controlling a volume of liquid from a controllable source of liquid dispensed by a liquid-dispensing system having at least one liquid dispenser that dispenses liquid at a first flow rate, the apparatus comprising: a liquid outlet through which the liquid flows at a second flow rate from the controllable source; and a volume sensor that provides a signal responsive to a volume of liquid dispensed by the liquid outlet; wherein the controllable source of liquid is turned off when a volume of liquid dispensed by the liquid outlet reaches a given volume. Preferably the apparatus comprises a receptacle that accumulates liquid dispensed by the liquid outlet. Preferably, the volume sensor senses the volume of liquid in the receptacle. Preferably, the receptacle comprises a valve controllable to be open or closed, wherein when the valve is open liquid drains out of the receptacle through the valve. In some preferred embodiments of the present invention the valve is manually controlled. In some preferred embodiments of the present invention the valve is controllable to be open and closed responsive to a signal generated by the volume sensor.

In embodiments in which the valve is opened and closed responsive to a signal generated by the volume sensor, preferably, the valve is opened responsive to a signal generated by the volume sensor when the volume sensor senses the given volume. Preferably, the valve is closed responsive to a signal generated by the volume sensor when the volume sensor senses that a desired volume of liquid is drained from the receptacle.

Preferably the source of liquid is turned on responsive to a signal generated by the volume sensor when the desired volume of water is drained from the receptacle. Preferably, the source of liquid is turned on following a delay after receiving the signal from the volume sensor. The delay is preferably adjustable.

In some preferred embodiments of the present invention the volume sensor comprises: a float that floats on the surface of the liquid in the receptacle; and at least one switch having first and second states and a trigger such that when the trigger is contacted the switch switches from the first state to the second state and the volume sensor generates an output signal; wherein the trigger is mounted at a height inside the receptacle so that when the volume of the liquid in the receptacle is equal to the given volume, the level of the liquid brings the float to the given height so as to contact the trigger. Preferably, the height of the trigger is adjustable so as to adjust the magnitude of the given volume. There is further provided, in accordance with a preferred embodiment of the present invention, an irrigation system according comprising: an apparatus according to a preferred embodiment of the present invention; a manifold connected to the water-source; and at least one water-dispenser connected to the manifold that dispenses water at the first flow rate when the water-source is on. In some embodiments of the present invention, each of the at least one water dispensers dispenses water at a same first flow-rate. In other preferred embodiments of the present invention the at least one water dispenser comprises at least two water-dispensers and the first flow rates for at least two water-dispensers are different. In some preferred embodiments of the present invention, the second flow rate in the liquid outlet is equal to a first flow rate of at least one of the water-dispensers.

In some irrigation systems, in accordance with a preferred embodiment of the present invention the liquid outlet comprises a shunt connected to the manifold, so that when water flows in the manifold the shunt diverts a known portion of water flowing in the manifold to flow through the shunt.

There is further provided in accordance with a preferred embodiment of the present invention a composite irrigation system comprising: a manifold for delivering water from a water source; a plurality of irrigation systems according to a preferred embodiment of the present invention; wherein the manifold of each of the plurality of the irrigation systems is connected by a valve to the manifold and wherein the apparatus of the irrigation system controls the valve.

BRIEF DESCRIPTION OF FIGURES The invention will be more clearly understood by reference to the following description of preferred embodiments thereof read in conjunction with the figures attached hereto. In the figures, identical structures, elements or parts which appear in more than one figure are labeled with the same numeral in all the figures in which they appear. The figures are listed below and: Fig. 1 shows schematically an irrigation system comprising a water monitor, in accordance with a preferred embodiment of the present invention; Fig. 2 shows schematically another irrigation system comprising a water monitor, in accordance with a preferred embodiment of the present invention; and

Fig. 3 shows schematically an irrigation system comprising a plurality of water monitors, in accordance with a preferred embodiment of the present invention. DESCRIPTION OF PREFERRED EMBODIMENTS Fig. 1 shows schematically an irrigation system 20 irrigating a plurality of plants 22, in accordance with a preferred embodiment of the present invention. Irrigation system 20 preferably comprises a water pump 24 that pumps water from a water source (not shown) to a manifold 26. A plurality of preferably identical water dispensers 28 (only three are shown in Fig. 1 by, way of example) is coupled to manifold 26 using methods known in the art. Each water-dispenser 28 irrigates, by way of example, a single plant 22.

Irrigation system 20 comprises a water monitor 30, in accordance with a preferred embodiment of the present invention. Water monitor 30 comprises a receptacle 32 having a bottom 34 an outlet spigot 36 preferably controlled by a manual valve 38 and a water volume sensor 40 for sensing the volume of water in receptacle 32. A monitoring dispenser 42, preferably identical to water dispensers 28 is connected to manifold 26 and positioned so that water that flows out of momtor dispenser 42 enters receptacle 32.

Preferably, volume sensor 40 generates a signal on a control line 44 responsive to a volume of water it senses in receptacle 32. Preferably, control line 44 is connected to water pump 24 using methods known in the art so that a signal from volume sensor 40 shuts off water pump 24. Preferably, volume sensor 40 senses a volume of water in receptacle 32 by sensing the height of the volume of water in receptacle 32 and when water reaches a predetermined height in receptacle 32, a signal generated by volume sensor 40 shuts off water pump 24. Determining the predetermined height at which volume sensor 40 generates a "shut-off signal is referred to as calibrating water momtor 30.

Many different types of sensors are known in the art that can be used for volume sensor 40 and many different ways are known by which a signal from volume sensor 40 can be used to shut off pump 24. For example, volume sensor 40 might comprise a float and a microswitch having an activation trigger. The microswitch is mounted to receptacle 32 so that the activation trigger is at a certain height above bottom 34 of receptacle 32. The float floats on the top of the water in receptacle 32. When water in receptacle 32 reaches a level such that the float reaches the certain height at which the activation trigger is located, the float touches the trigger and the microswitch generates a shut-off signal. The microswitch is positioned at a height above bottom 34 so that the shut-off signal is generated when receptacle 32 is filled with a desirable volume of water.

In some preferred embodiments of the present invention, volume sensor 40 provides a signal having a voltage that is responsive to the height of water in receptacle 32. The height is sensed by a change in resistance of a component of sensor 40, which change is caused by contact of the component with the water. When the signal voltage reaches a threshold voltage indicating that water in receptacle 32 has reached a desired height, the voltage activates a switch to shut off pump 24. The threshold voltage is controllable so as to determine the desired height at which water pump 24 shuts off.

Other sensors or means for measuring the volume of water in receptacle 32 and generating a signal in response to the measured volume that shuts off water pump 24, in accordance with a preferred embodiment of the present invention, will occur to persons of the art. Irrigation system 20 is controllable, in accordance with a preferred embodiment of the present invention, to provide an irrigation cycle during which a substantially same desired volume of water is delivered to each one of plants 22. Prior to the beginning of an irrigation cycle receptacle 32 is preferably empty and water monitor 30 is calibrated so that when water fills receptacle 32 to a height indicated by dashed line 46 a signal from water sensor 40 turns off pump 24. Height 46 is determined so that a volume of water that fills receptacle 32 to height 46 is equal to the desired volume of water that is to be delivered to each plant 22.

The irrigation cycle begins when pump 24 is turned on. Water then begins to flow out of each of dispensers 28 to deliver water to each of plants 22 at preferably substantially the same rate. Water also flows out of monitor dispenser 42 to fill receptacle 32 at substantially the same rate that water flows out of each of dispensers 28. In Fig. 1 receptacle 32 is shown at a time after the beginning of an irrigation cycle at which receptacle 32 is partially filled with water from monitoring dispenser 42. The water is indicated by wavy lines 48 and has reached a level indicated by a wavy line 50 that is below height 46. When water 48 from monitoring dispenser 42 fills receptacle 32 with the desired volume of water, water level 50 in receptacle 32 reaches height 46 and a signal from volume sensor 40 turns off water pump 24. Monitoring dispenser 42 delivers water to receptacle 32 at the same rate that each of dispensers 28 deliver water. Therefore, at the time that the signal from volume sensor 40 shuts off water pump 24, each of dispensers 28 has delivered the desired volume of water to each of plants 22. To begin the irrigation cycle over again, receptacle 32 is preferably drained of water by opening valve 38 of spigot 36 and water pump 24 is turned on.

In the preferred embodiment of the present invention described above, an irrigation cycle begins with receptacle 32 empty and the volume of water delivered to a plant 22 during an irrigation cycle depends upon the height to which water monitor 30 is calibrated. Changing the calibration height of water monitor 30 changes the volume of water delivered to a plant 22 in an irrigation cycle.

Alternatively, a volume of water delivered by irrigation system 20 to a plant 22 in an irrigation cycle can be determined by a volume of water in receptacle 32 at the beginning of the irrigation cycle. The calibration height of water monitor 30 is fixed at a first height. At the beginning of an irrigation cycle receptacle 32 is filled with water to a second height. The volume of water delivered to a plant 22 in an irrigation cycle is equal to the volume of water that must be added to receptacle 32 to raise the level of water in receptacle 32 from the second level to the first level. Changing the second height changes the amount of water delivered to a plant 22.

In accordance with a preferred embodiment of the present invention, to aid in determining to which second height to fill receptacle 32 in order to deliver a desired amount of water to a plant 22, receptacle is formed so that the level of water in the receptacle is visible.

Preferably, receptacle 32 is graduated to enable accurate visual estimation of a volume of water in the receptacle corresponding to a given level of water in the receptacle.

In some preferred embodiments of the present invention, monitoring dispenser 42 is not identical to water dispensers 28. However, the ratio of the flow rate at which monitoring dispenser 42 fills receptacle 32 to the flow rate at which water is delivered by a dispenser 28 is known. In this case, a volume of water needed to fill receptacle 32 in order for volume sensor 40 to generate a shut-off signal is determined to be equal a volume of water to be delivered to a plant 22 times the known ratio.

Fig. 2 shows another irrigation system 60, in accordance with a preferred embodiment of the present invention. Irrigation system 60 is very similar to irrigation system 20 except that irrigation system 60 comprises a controller 62. Controller 62 receives signals generated by volume sensor 40 on a signal line 64 that indicate a volume of water in receptacle 32. Signals from controller 62 on a signal line 66 that connects controller 62 to pump 24 control pump 24 to be on or off. Furthermore, whereas in irrigation system 20 spigot 36 is opened or closed by a manually operated valve 38, in irrigation system 60, spigot 36 is opened or closed by a valve 68 controlled by signals generated by controller 62 on a signal line 70. Preferably controller 62 comprises a clock (not shown) that provides timing signals and controller 62 is programmable to control water pump 24 and valve 68 responsive to both timing signals from the clock and signals from volume sensor 40. In accordance with a preferred embodiment of the present invention, irrigation system

60 is programmable to automatically provide a sequence of irrigation cycles that delivers predetermined quantities of water to each of plants 22 at a desired frequency. For example, assume that controller 62 is programmed to shut off pump 24 when water in receptacle 32, which is shown at a level indicated by a wavy line 70, reaches a first height 72. After controller 62 turns off pump 24 controller 62 is programmed to open valve 68 in order to drain water from receptacle 32. Valve 68 remains open until water in receptacle 32 drops to a second height 74, at which time controller 62 closes valve 68. After a desired time delay, as measured by suitable signals from the clock, from a time that controller 62 turns off pump 24, controller 62 is programmed to turn on pump 24. Programmed in this way, irrigation system 60 will periodically irrigate each of plants 22 during irrigation cycles that recur periodically following time intervals equal to the desired time delay. The amount of water that each plant 22 receives during an irrigation cycle is equal to the volume of water needed to raise the level of water in receptacle 32 from second height 74 to first height 72.

Other, and more complicated, ways of programming irrigation system 60, or an irrigation system in accordance with a preferred embodiment of the present invention that is similar to irrigation system 60, will readily occur to persons of the art. For example, controller 62 can be programmed to change the volumes of water that plants 22 receive in different irrigation cycles by changing second height 74 according to a desired program. Or, delay times between irrigation cycles can be changed according to a desired program.

Fig. 3 shows another irrigation system 80 in accordance with a preferred embodiment of the present invention. Irrigation system 80 is advantageous in that it can deliver substantially the same volumes of water to a large number of plants substantially independent of drops in water pressure in pipes that provide water to dispensers that deliver water to the plants.

Irrigation system 80 preferably comprises a water pump 82 that provides water to a main manifold 84. A plurality of preferably identical secondary manifolds 86 (only three of which are shown) is connected to main manifold 84. A plurality of preferably identical water dispensers 28 (only three of which are shown) is connected to each secondary manifold 86 and each water-dispenser 28 is shown in Fig. 3, by way of example, irrigating a single plant 22.

Each secondary manifold 86 is connected to main manifold 84 by a valve 88 that is controlled to be open or closed by a water-monitor 30, in accordance with a preferred embodiment of the present invention. Water flows into each water-monitor 30 from its secondary manifold 86 via a monitoring dispenser 42 that is preferably identical to dispensers 28. The dimensions of each secondary manifold 86 and the number of dispensers 28 connected to it are chosen to prevent substantial differences in flow rates of the dispensers 28 that might result from water pressure drop along the secondary manifold. As a result, when irrigation system 80 is operating, dispensers 28 on a same secondary manifold 86 deliver water to plants 22 at substantially the same flow rate. Irrigation system 80 is capable of delivering in an irrigation cycle the same amounts of water to each of a large numbers of plants 22 substantially independent of drops in water pressure along main manifold 84. For example, assume that water-monitors 30 are calibrated so that a same desired volume of water must flow into each water-monitor 30 before the water- monitor 30 generates a signal to close the valve 88 that it controls. Assume that pump 82 is on and that an irrigation cycle of irrigation system 80 begins at a certain time at which all valves 88 are opened simultaneously.

At the certain time, each water-dispenser 28 begins to deliver water to the plant 22 that it irrigates. Because of pressure drop in main manifold 84 however, flow rates of water dispensers 28 that are connected to secondary manifolds 86 closer to pump 84 may be greater than flow rates of dispensers 28 connected to a secondary manifold 84 farther from pump 82. However, each valve 88 is closed only after the water-monitor 30 that controls it receives the same desired volume of water. As a result, each dispenser 28 continues to deliver water to the plant 22 that it irrigates until the total volume of water delivered to the plant 22 is substantially equal to the desired volume of water. The volume of water received by a plant 22 during an irrigation cycle is substantially independent of a flow rate at which it receives the water.

Therefore, even if the flow rate at which the plant 22 receives water depends upon pressure drop in main manifold 84, the volume of water that the plant 22 receives is substantially independent of the pressure drop. Pressure drop in main manifold 84 may determine times after the beginning of the irrigation cycle at which valves 88 close. Valves 88 of secondary manifolds 86 that are closer to pump 82 may close earlier than valves 88 that are farther from pump 82. However pressure drop in main manifold 84 will not affect substantially the volume of water delivered to each of plants 22. In the claims and specification of the present application, each of the verbs, "comprise",

"include" and "has", and conjugates thereof, mean that the object or objects of the verb are not necessarily a complete listing of all the components, elements or parts of the subject or subjects of the verb.

The present invention has been described using non-limiting detailed descriptions of preferred embodiments thereof. Variations of the embodiments described will occur to persons of the art. The detailed descriptions are provided by way of example and are not meant to limit the scope of the invention, which is limited only by the following claims:

Claims

1. Apparatus for controlling a volume of liquid from a controllable source of liquid dispensed by a liquid-dispensing system having at least one liquid dispenser that dispenses liquid at a first flow rate, said apparatus comprising: a liquid outlet through which said liquid flows at a second flow rate from said controllable source; and a volume sensor that provides a signal responsive to a volume of liquid dispensed by said liquid outlet; wherein said controllable source of liquid is turned off when a volume of liquid dispensed by said liquid outlet reaches a given volume.

2. Apparatus according to claim 1 comprising a receptacle that accumulates liquid dispensed by said liquid outlet.

3. Apparatus according to claim 2 wherein said volume sensor senses the volume of liquid in said receptacle.

4. Apparatus according to claim 3 wherein said receptacle comprises a valve controllable to be open or closed, wherein when said valve is open liquid drains out of said receptacle through said valve.

5. Apparatus according top claim 4 wherein said valve is manually controlled.

6 Apparatus according to claim 4 wherein said valve is controllable to be open and closed responsive to a signal generated by said volume sensor.

7. Apparatus according to claim 6 wherein said valve is opened responsive to a signal generated by said volume sensor when said volume sensor senses said given volume.

8. Apparatus according to claim 7 wherein said valve is closed responsive to a signal generated by said volume sensor when said volume sensor senses that a desired volume of liquid is drained from said receptacle.

9. Apparatus according to claim 8 wherein said source of liquid is turned on responsive to a signal generated by said volume sensor when said desired volume of water is drained from said receptacle.

10. Apparatus according to claim 9 wherein said source of liquid is turned on following a delay after receiving said signal from said volume sensor.

11. Apparatus according to claim 10 wherein said delay is adjustable.

12. Apparatus according to any of claims 2-11 wherein said volume sensor comprises: a float that floats on the surface of said liquid in said receptacle; and at least one switch having first and second states and a trigger such that when said trigger is contacted said switch switches from said first state to said second state and said volume sensor generates an output signal; wherein said trigger is mounted at a height inside said receptacle so that when the volume of said liquid in said receptacle is equal to said given volume, the level of said liquid brings said float to said given height so as to contact said trigger.

13. Apparatus according to claim 12 wherein said height of said trigger is adjustable so as to adjust the magnitude of said given volume.

14. An irrigation system comprising: apparatus according to any of the preceding claims; a manifold connected to said water-source; and at least one water-dispenser connected to said manifold that dispenses water at said first flow rate when said water-source is on.

15. An irrigation system according to claim 14 wherein each of said at least one water dispensers dispenses water at a same first flow-rate.

16. An irrigation system according to claim 14 wherein said at least one water dispenser comprises at least two water-dispensers and wherein said first flow rates for at least two water- dispensers are different.

17. An irrigation system according to claim 15 or claim 16 wherein said second flow rate in said liquid outlet is equal to a first flow rate of at least one of said water-dispensers.

18. An irrigation system according to any of claims 14-17 wherein said liquid outlet comprises a shunt connected to said manifold, so that when water flows in said manifold said shunt diverts a known portion of water flowing in said manifold to flow through said shunt.

19. A composite irrigation system comprising: a manifold for delivering water from a water source; a plurality of irrigation systems according to any of claims 14-18; wherein the manifold of each of said plurality of said irrigation systems is connected by a valve to said manifold and wherein said apparatus of said irrigation system controls said valve.