Patent Application
20140261693
1. Field of the Invention
The present invention relates to irrigation and, in particular, to a system and method for controlling irrigation systems to prevent freezing in irrigation systems and components.
2. Discussion of the Related Art
It is known to shut down irrigation systems during the colder months to prevent the freezing of water within the main supply and lateral lines for prevention of damage to such lines. During the fall season, it is common to employ local irrigation contractors to evacuate water from their underground irrigation systems in an effort to prevent the water lines from freezing. Typically, before an irrigation system is shut down, an operator has to manually drain or forcibly purge the water from the irrigation system. Similarly, when warmer months arrive, the contractor has to return to the irrigation system site to energize the irrigation system.
This process, more commonly referred to as winter shut down or winterization, can be a source of frustration for home and business owners in trying to schedule the service at the most optimal time as well as the possibility of system damage at the time of service or discovering it in the spring when the system is energized. For example, forced air evacuations of automatic irrigation systems are sometimes performed at dangerously high pressures and flow rates and can result in immediate as well as long-term system damage to critical irrigation components, i.e. valves, vacuum breakers, spray heads, rotors and pipe connections. Further, if damage of this nature is not discovered at the time of spring start-up, significant collateral damage can result, including, but not limited to, erosion, seed washout, sink hole formation, property flooding and plant species termination.
Known irrigation equipment freeze protection systems either conduct a temperature threshold-induced automatic shutdown and draining of the main line of the system, hot water injection into the main and lateral zones, or a continual weeping of main line water until a full system manual shutdown can be performed. Such systems can activate automatically based on input from air and/or water temperature sensors. In addition, systems that rely on temperature sensors may respond to an unusual single day drop in temperature and prematurely activate the winterization system for the entire winter prior to the actual arrival of colder temperatures.
Several embodiments of the invention provide methods and apparatus for winterization of an irrigation system to prevent freezing during the colder months.
In one embodiment, an irrigation system comprises: an antifreeze supply unit coupled to a water line of the irrigation system, the antifreeze supply unit including a storage container containing a liquid antifreeze; and a control unit in communication with the antifreeze supply unit, the control unit being configured to send a signal to the antifreeze supply unit and the antifreeze supply unit being configured to inject at least some of the liquid antifreeze from the antifreeze storage container into the water line in response to receiving the signal from the control unit.
In another embodiment, a control unit for controlling an irrigation system comprises: a memory storing temperature thresholds of at least one of air and water temperatures associated with a geographical location of the irrigation system, the memory including at least a lower temperature threshold; an output configured to be in communication with an antifreeze supply unit including an antifreeze storage container coupled to a water line of the irrigation system; and a processor coupled to the memory and the output; wherein the processor is configured to generate a signal at the output upon a determination by the processor that at least one of air and water temperature approaches the lower temperature threshold, the signal being configured to cause the antifreeze supply unit to inject at least some of the liquid antifreeze from the antifreeze storage container into the water line.
In yet another embodiment, a method for controlling an irrigation system comprises: outputting a signal from a control unit of an irrigation system comprising a water line and an antifreeze supply unit coupled to the water line and including an antifreeze storage container containing a liquid antifreeze, wherein the control unit comprises a processor and memory containing instructions executable by the processor; receiving the signal at the antifreeze supply unit; and injecting, responsive to the signal received at the antifreeze supply unit, at least some of the liquid antifreeze from the antifreeze storage container of the antifreeze supply unit into the water line.
The above and other aspects, features and advantages of several embodiments of the present invention will be more apparent from the following more particular description thereof, presented in conjunction with the following drawings.
Corresponding reference characters indicate corresponding components throughout the several views of the drawings. Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of various embodiments of the present invention. Also, common but well-understood elements that are useful or necessary in a commercially feasible embodiment are often not depicted in order to facilitate a less obstructed view of these various embodiments of the present invention.
The following description is not to be taken in a limiting sense, but is made merely for the purpose of describing the general principles of exemplary embodiments. The scope of the invention should be determined with reference to any claims supported by this specification.
Reference throughout this specification to “one embodiment,” “an embodiment,” “some embodiments” or similar language means that a particular feature, structure, or characteristic described in connection with the embodiment/s is included in at least one embodiment of the present invention. Thus, appearances of the phrases “in one embodiment,” “in an embodiment,” “some embodiments” and similar language throughout this specification may, but do not necessarily, all refer to the same embodiment(s).
Furthermore, the described features, structures, or characteristics of the invention may be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided to provide a thorough understanding of embodiments of the invention. One skilled in the relevant art will recognize, however, that the invention can be practiced without one or more of the specific details, or with other methods, components, materials, and so forth. In other instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring aspects of the invention.
Referring to
Water to the system 10 is supplied from a main water supply 18 and flows via a master or gate valve 19 through a main water line 15, a plurality of lateral water lines 22a, 22b, and 22c, and a plurality of zone valves 24a, 24b, and 24c (under control by the irrigation controller 12) to a plurality of sprinklers 25a, 25b, and 25c. It will be appreciated that while three water lines 22a, 22b, and 22c having been shown as branches of the main water line 15, the system 10 can include any number of lateral water lines branching from the main water line 15. As discussed in more detail below in reference to the embodiment of
The main irrigation controller 12, which controls water flow in the main line 15 and the lateral zones 22a, 22b, and 22c of the irrigation system 10 during the normal irrigation operation of the system 10, is configured to output activation signals (e.g., 24 volt A/C power signals) to respective ones of a plurality of lateral activation lines depicted by the dashed lines 21a, 21b, and 21c, each coupled to a respective zone valve 24a, 24b, and 24c located in a region to be irrigated. The presence of an activation signal on a given activation line 21a, 21b, 21c causes the opening of the respective zone valve 24a, 24b, 24c, and the absence of such activation signal results in the closing of the zone valve. As is well known, each zone valve 24a, 24b, and 24c controls water flow to one or more sprinkler devices 25a, 25b, and 25c, drip lines and/or other irrigation devices that may be coupled to each valve 24a, 24b, and 24c. Typically, the watering devices (e.g., 25a, 25b, and 25c) coupled to a given zone valve 24a, 24b, and 24c define a watering zone.
While the main irrigation controller 12 is shown in
In an embodiment depicted in
In another embodiment, the winterization control unit 214 can include a processor 216 electrically coupled to a power supply 218 and a memory 220, as shown in
As discussed in more detail below, the winterization control units 14, 114, and 214 can be coupled to the main irrigation controller 12 directly via a wired or wireless connection or an interface. Alternatively, the winterization control units 14, 114, and 214 can be implemented as a part of the main irrigation controller 12. For example, any one of the winterization control units 14, 114, and 214 may be implemented as a module that is configured to be inserted into a modular main irrigation controller.
In the embodiment illustrated in
In another embodiment illustrated in
While the winterization control unit 314 and the main irrigation controller 312 have been illustrated in
In the embodiment illustrated in
The connector 442 can include pins that carry power and data signals from the winterization control unit 414 to the main irrigation controller 412. While one module mounting location 440 has been shown in
The connector 442 permits the processor 416 of the winterization control unit 414 to send signals to and/or receive signals from the controller 413 (for example, a microcontroller or control system) of the main irrigation controller 412. For example, the processor 416 of the winterization control unit 414 can send a signal via an electrical connection 437 through the connector 442 and the module mounting location 440 to the controller 413 of the main irrigation controller 412 to either shut off electrical power, or to provide electrical power to the main irrigation controller 412. It is to be appreciated that such a signal can be generated by the processor 416 in response to an input such as a command entered manually by a user via the user interface 428 and/or an input such as a command initiated at a central station or a central controller remote to the winterization control unit module 414.
While the winterization control unit 414 and the main irrigation controller 412 have been illustrated in
In the embodiment depicted in
In the embodiment illustrated in
As shown in
The winterization control unit 14 also has a water temperature input via a connection 34 from a water temperature sensor 36 coupled to the main water line 20. It will be appreciated that the connection 34 can be wired or wireless. The water temperature sensor 36 can be coupled to the main water line 15 to measure the fluid (e.g., water, or a mixture of water and liquid antifreeze 105) temperature in the main water line 15. In one approach, the water temperature sensor 36 includes circuitry and a transmitter configured to send signals to the winterization control unit 14. The water temperature sensor 36 can be programmed to perform water temperature measurements at predetermined intervals or continuously, and to send signals including water temperature measurement data at predetermined intervals, or in real time, to the winterization control unit 14.
With reference to
Downstream of the control valve 40, the system 10 can include a flow sensor 41 coupled to the main water line 15 and in communication with the winterization control unit 14 via a connection 43, which can be a wired or a wireless connection. In one approach, the flow sensor 41 includes circuitry and a transmitter configured to send signals to the winterization control unit 14, as discussed in more detail below.
As shown in
With further reference to
In the illustrated embodiment, the antifreeze supply unit 100 includes a housing 102 and an antifreeze storage container 104 positioned at least in part within the housing 102. It is to be appreciated that the antifreeze storage container 104 can be located entirely within the housing 102, partly within the housing 102, or entirely outside of the housing 102. For example, the antifreeze storage container 104 may be physically separate from the housing 102 of the antifreeze supply unit 100 and connected by one or more pipes to the housing 102 of the antifreeze supply unit 100. In one approach, the housing 102 of the antifreeze supply unit 100 is a valve box. The antifreeze storage container 104 may have a capacity of between about 5 gallons to about 10 gallons and can include a spout 108 with a removable cap 110 that allows a user such as a homeowner or a contractor to easily replenish the level of the liquid antifreeze 105 in the antifreeze storage container 104. Conversely, the spout 108 can be used to drain the antifreeze storage container 104, if necessary. Preferably, the liquid antifreeze 105 is non-toxic, biodegradable, and environmentally safe.
In one approach, the liquid antifreeze 105 is a relatively pure mixture including food-grade propylene glycol. Propylene glycol is a generally clear, odorless, tasteless, non-volatile, viscous liquid with a melting point of −59° C. and a boiling point of 188.2° C. Propylene glycol is in a class of compounds known as organic alcohols. It has a relatively low vapor pressure and is thus non-volatile in nature. Similar to a more well-known antifreeze, ethylene glycol, which is commonly used in automotive coolant applications, propylene glycol is extremely miscible with water. In one approach the liquid antifreeze 105 can include a color dye to add color and distinguish the liquid antifreeze 105 from pure propylene glycol (which is colorless) to visibly indicate that the liquid antifreeze 105 is not meant for human consumption. It is to be appreciated that instead of propylene glycol, the liquid antifreeze 105 can include other suitable compounds, for example, methanol, ethanol, sodium chloride solution, or polyethylene glycol, or the like, or mixtures thereof.
With further reference to the embodiment of
In one approach, the pump 106 of the antifreeze supply unit 100 includes internal logic circuitry and a processor configured to receive power and/or data signals from any one of the winterization control units 14, 114, 214, 314, and 414, and, in response to the received signals, to cause the liquid antifreeze 105 to be injected from the antifreeze storage container 104 into the main water line 15. In another approach, the antifreeze supply unit 100 can include an input, implemented into, or electrically coupled to the pump 106, that can receive an electrical signal (e.g., an A/C power signal) from the winterization control unit 14 that would cause the pump 106 to inject the liquid antifreeze 105 into the main line 15. In yet another approach, the antifreeze supply unit can be configured such that it lacks the pump 106, and the antifreeze storage container 104 is a pressurized container configured to, upon the opening of a valve, to deliver the liquid antifreeze 105 to the main water line 15.
In one approach, the processors 16, 116, 216, 316, and 416 of the winterization control units 14, 114, 214, 314, and 414 are programmed to analyze trends in data received from the air temperature sensor 32 and the water temperature sensor 36. To that end, the memory 20, 120, 220, 320, and 420 of each winterization control unit 14, 114, 214, 314, and 414 can include stored historical values and trends of air temperatures, water temperatures, and ground temperatures associated with the geographical location (for example, based on zip code) where the irrigation system 10 is located. In addition, the memory 20, 120, 220, 320, and 420 of each winterization control unit 14, 114, 214, 314, and 414 can include predetermined minimum and maximum temperature thresholds, which, when approached, would trigger the winterization control units 14, 114, 214, 314, and 414 to initiate the winterization cycle, as described in more detail below. In one approach, the processors 16, 116, 216, 316, and 416 of the winterization control units 14, 114, 214, 314, and 414 are programmed to analyze the air temperature readings received from the sensors 32 and 36 over a predetermined time interval (for example twice daily, once daily, every other day, once every two days, once a week, or any other suitable interval). This analysis is performed in view of the air and water temperature historical trend values to predict whether the air and/or water temperature trend is approaching the predetermined maximum or minimum temperature threshold stored in the memory 20, 120, 220, 320, and 420 of the winterization control units 14, 114, 214, 314, and 414.
The winterization control units 14, 114, 214, 314, and 414, in addition to being programmed to measure and respond to trends in temperature, can have specific calendar dates stored in their memories 20, 120, 220, 320, and 420. The specific calendar days (when reached) can cause the winterization control units 14, 114, 214, 314, and 414 to either initiate the winterization cycle, or to exit the winterization cycle and return to normal operation of the irrigation system 10. For example only, the winterization control units 14, 114, 214, 314, and 414 can be programmed with a date of November 1, November 15, or December 1, on which, regardless of the temperature trends determined based on temperature sensor input, the winterization control units 14, 114, 214, 314, and 414 would begin the winterization cycle. Similarly, the winterization control units 14, 114, 214, 314, and 414 can be programmed with a calendar date of February 15, March 1, or March 15, on which, regardless of the temperature trends, the winterization control units 14, 114, 214, 314, and 414 would begin to exit from the winterization cycle and return to the normal irrigation operation of the system 10. In some embodiments, these calendar dates may be stored as a result of manual user input to the winterization control unit. In addition, the winterization control units 14, 114, 214, 314, and 414 can be programmed such that a user such a homeowner or contractor user can override the stored temperature trends and calendar dates by and initiate or exit from the winterization cycle by a manual input. In different embodiments, this manual input from the user can be directly provided at the physical location of the winterization control units 14, 114, 214, 314, and 414, or remotely, for example, from a central station or a mobile hand-held unit. In one approach, to enable reception of remote user inputs, the winterization control units 14, 114, 214, 314, and 414 include a network card and/or a wireless receiver adapted to receive user input from a remote internet server via a wired or wireless (e.g., satellite or cellular) connection.
During the colder months when air temperature typically begins a negative trend, and the processors 16, 116, 216, 316, and 416 of the winterization control units 14, 114, 214, 314, and 414 determine, for example, that the air temperature data received over a predetermined time period from the air temperature sensor 32 indicates a predictable trend that the air temperature will go below the low temperature threshold stored in the memory 20, 120, 220, 320, and 420 within a predetermined period of time (for example, three days, one week, 10 days, etc.), the processors 16, 116, 216, 316, and 416 are programmed to initiate a winterization cycle, which is described in more detail below. In one approach, the winterization control units 14, 114, 214, 314, and 414 can include a visual indicator or an audible alarm that indicates to a user such as a homeowner or a contractor that the winterization cycle is about to begin or has begun. In one approach, the visual indicator or audible alarm can optionally indicate to the user that the water supply 18 to the main water line 15 has been shut off.
Generally, during the winterization cycle of the exemplary system 10 depicted in
In one aspect, the liquid antifreeze 105 is introduced from the antifreeze storage container 104 of the antifreeze supply unit 100 into the main water line 15 via the one way injection port 46 at a predetermined pressure until the concentration of the liquid antifreeze 105 required to protect the irrigation system 10 down to the minimum expected air and/or ground temperature is reached. As discussed in more detail below, the process of injecting the antifreeze solution 105 from the antifreeze storage container 104 of the antifreeze supply unit 100 into the main water line 15 continues until the main line 15 and all the lateral lines (e.g., 22a, 22b, and 22c) of the irrigation system 10 have been treated with the liquid antifreeze 105.
With reference to FIGS. 1 and 8-10, one method of operation of the irrigation control system 10 will now be described. While reference will be made to the winterization control unit 14 of
With reference to
As discussed above and depicted at step 506, the winterization control unit 14 receives ambient air temperature data and water temperature data at predetermined intervals from the air temperature sensor 32 and the water temperature sensor 36, respectively. At step 508, the processor 16 of the winterization control unit 14 can access the historical temperature trends stored in the memory 20 and determine whether the trend in the received air temperature readings is such that the air temperature is likely to approach the predetermined low temperature threshold stored in the memory 20 of the winterization control unit 14. If the answer is “yes,” at step 510, the processor 16 of the winterization control unit 14 determines whether the received water temperature readings indicate a trend that the water temperature in the main water line 15 will remain above a minimum threshold temperature, for example, above a minimum threshold of 35° F. or 2° C. (in one specific example, the threshold is 1.67° C.). It is understood that the minimum threshold is preferably near the freezing point of the liquid normally present in the lines, e.g., with water, the minimum threshold may be a value within a range of between 1-7° C.
If the temperatures in the main water line 15 are determined by the winterization control unit 14 to be below the predetermined minimum threshold, at step 512, a temporary irrigation system shutdown is performed where the winterization control unit 14 executes a temporary irrigation system shutdown in step 514 after which steps 506 and 508 are repeated. If the winterization control unit 14 determines at step 508 that the air temperature is not at (or below) the predetermined low temperature threshold, the main irrigation controller 12 reverts back to its normal operation mode, shown by the arrow going from step 508 back to step 500 in
If, however, the winterization control unit 14 determines, at step 508, that the air temperature is at or below the predetermined temperature threshold, and determines, at step 510, that the in-pipe water temperature is at or below the predetermined low temperature threshold, the winterization control unit 14, at step 516, begins the execution of an extended system shutdown for winter, otherwise known as winterization cycle, or simply winterization. If the winterization control unit 14 includes a visual indicator to alert the user that the winter shutdown has been initialized, at step 518, the winterization control unit 14 causes the visual indicator (e.g., an LED light) to be illuminated. In another approach, the visual indicator is a message on a display of the winterization control unit 14, or an audible alarm signal.
At step 520, the processor 16 of the winterization control unit 14 cross-references antifreeze concentration values associated with the zip code where the winterization control unit 14 is located. In one approach, the antifreeze concentration values are preset by a user and stored in the memory 20 of the winterization control unit 14. Next, in one approach shown in step 522, the winterization control unit 14 sends a signal (e.g., an electrical power signal or a data signal) that turns off electrical power to the main irrigation controller 12, shutting the main irrigation controller 12 down. For example, as shown in
With the main irrigation controller 12 being shut down, at step 524, the winterization control unit 14 sends a signal (e.g., an electrical power signal or a data signal) to the control valve 40 via the connection line 38 to switch input from the water supply 18 in the main water line 15 to the liquid antifreeze 105 in the antifreeze concentrate delivery line 44. At step 526, the winterization control unit 14 activates a selected one of irrigation zones 22a, 22b, and 22c coupled to the zone valves 24a, 24b, and 24c, respectively.
Then, at step 528, the winterization control unit 14 sends a signal that causes the pressure reducing valve 48 to assume a position adapted to provide a predetermined flow rate desired for injecting the liquid antifreeze 105 from the antifreeze storage container 104 of the antifreeze supply unit 100 into the main water line 15. Finally, at step 530, the winterization control unit 14 sends a signal to the antifreeze supply unit 100 via the connection 54 that causes the antifreeze supply unit 100, and more specifically, the pump 106 of the antifreeze supply unit 100, to dispense the liquid antifreeze 105 from the antifreeze storage container 104 of the antifreeze supply unit. The liquid antifreeze 105 is dispensed from the antifreeze storage container 104 at a flow rate and pressure directed by the signal received by the antifreeze supply unit 100 from the winterization control unit 14 into the main water 14 until the predetermined concentration of the liquid antifreeze 105 in the main water line 15 and each irrigation zone 22a, 22b, and 22c is achieved.
In one approach, the signal from the winterization control unit 14 is generated by the processor 16 and sent via the connection 54 to a logic circuitry located within the pump 106 of the antifreeze supply unit 100, with the logic circuitry being adapted to interpret this signal and initiate the injection of the liquid antifreeze 105 from the antifreeze storage container 104 of the antifreeze supply unit 100 into the main water line 15. In another approach, the signal from the winterization control unit 14 is generated by the processor 16 and sent via the connection 54 to a logic circuitry located away separate from the pump 106, for example, on the housing 102 of the antifreeze supply unit 100, or to an electrical input directly coupled to the pump 106, or indirectly coupled to the pump 106 via the housing 102 of the antifreeze supply unit 100 or via another intermediate device.
In one aspect, flow in the main line 15 is controlled by an electronic proportioning valve (not shown) located upstream of the control valve 40 and measured using the flow sensor 41. The flow sensor 41 can include circuitry and a transmitter configured to transmit the flow rates measured in the main water line 15 to the winterization control unit 14. The winterization control unit 14 is programmed to interpret the information received from the flow sensor 41 regarding the flow rate in the main water line 15 to determine a desired pressure and operating speed of the pump 106 of the antifreeze supply unit 100 for introducing the liquid antifreeze 105 from the antifreeze storage container 104 of the antifreeze supply unit 100 into the main water line 15.
With reference now to
As the lateral zones 22a, 22b, and 22c are sequentially activated and the antifreeze solution 105 is introduced into them, a pressure reading signal from the pressure sensor 28 attached to the main line 15 can be sent to the winterization control unit 14 at step 536. When the pressure reading signal is received from the pressure sensor 28, at step 538, the processor 16 of the winterization control unit 14 interprets this pressure reading signal to determine whether the liquid antifreeze 105 has reached the last spray head of a sprinkler (e.g., 25c).
If the answer at step 538 is no, at step 540, the winterization control unit 14 de-energizes the zone currently receiving the antifreeze solution 105 and activates the next zone in the sequence such that each zone 22a, 22b, and 22c of the system 10 is sequentially treated until the entire system 10 is filled with the antifreeze solution 105. If the answer at step 538 is yes, the winterization control unit 14 sends a signal to the control valve 40 via the connection 38 to turn the water supply off via the gate valve 19 at step 542.
With the control valve 40 being set to off with relation to the water supply 18, and preferably, with the gate valve 19 being set to off, the zones 22a, 22b, 22c and the pump 106 of the antifreeze supply unit 100 are de-energized at step 544. As described above, when the desired concentration of the liquid antifreeze 105 is reached in the main water line 15 and all lateral lines 22a, 22b, and 22c (detectable by flow rate/line length calculation or a change in pressure from a change in fluid density being emitted from spray heads), the pump 106 of the antifreeze supply unit 100 can be deactivated (to stop the injection of the liquid antifreeze 105 into the irrigation system 10). This deactivation of the pump 106 of the antifreeze supply unit 100 can be accomplished via a signal sent from the winterization control unit 14 to the antifreeze supply unit 100, or via a signal sent from a sensor (e.g., pressure sensor 28) to the antifreeze supply unit 100.
Also at step 544, pressure from the main line 15 is relieved through a drain port on the pressure reducing valve 48, and the control valve 40 is set to antifreeze input. Then, at step 546, the winterization control unit 14 is set to a lower power “sleep mode”, temperature protection limits are set, and the temperature trend monitoring mode is enabled, allowing the winterization control unit 14 to monitor the winterization cycle operation of the system 10. The temperature protection limits can be stored in the memory 20 of the winterization control unit 14 and represent a range of water temperatures (for example, +17° F. (20% by volume propylene glycol); +4° F. (30% by volume propylene glycol), −13° F. (40% by volume propylene glycol), −28° F. (50% by volume propylene glycol)) acceptable during the winterization cycle.
During the winterization cycle, the system 10 is preferably in a temperature monitoring, low power state designed to consume a minimal amount of power. This low power state includes both the winterization control unit 14 and the main irrigation controller 12. During the winterization cycle, the winterization control unit 14 can, at predetermined intervals, emerge from the sleep mode to receive temperature readings of the air, water, and/or ground temperatures. For example, during the winterization cycle, the air temperature sensor 32 and the water temperature sensor 36 can measure air and water temperatures, respectively, at predetermined intervals, and send signals containing air temperature and water temperature data to the winterization control unit 14.
Using the data received from the sensors 32 and/or 36, the temperature trending algorithm programmed into its processor 16, and optionally, the historical temperature data stored in its memory 20, at step 548, the winterization control unit 14 determines if the temperature of the irrigation system 10 is stable or appearing to migrate toward a warm temperature where freezing is no longer an issue, or a temperature below which the system 10 is no longer protected by the particular concentration of the liquid antifreeze 105 injected into the system 10 during the first winterization cycle. If the answer at step 548 is yes, in other words, if the processor 16 predicts that the temperatures are likely to approach one of the pre-defined upper and lower limits, the winterization control unit 14 determines whether the air and/or water temperature is expected to exceed the upper trend limit or the lower trend limit at step 550.
If the temperature trend is predicted by the processor 16 of the winterization unit 14 to drop below the temperature determined to be the minimum acceptable temperature based on the amount of liquid antifreeze 105 injected into the system 10, the winterization control unit 14 will conduct a partial system power up and begin an immediate purge of the main line 15 and the lateral lines 22a, 22b, and 22c, similar in sequence to the first winterization cycle (steps 518-530), using a higher concentration of the liquid antifreeze 105 necessary to obtain an increased level of protection against freezing (for example, 20% by volume propylene glycol freezes at +17° F.; 30% by volume propylene glycol freezes at +4° F.; 40% by volume propylene glycol freezes at −13° F.; and 50% by volume propylene glycol freezes at −28° F.). In this case, at step 552, the processor 16 of the winterization control unit 14 recalculates the expected minimum temperature of the system 10 and determines the liquid antifreeze 105 concentration necessary to sufficiently prevent the system 10 from freezing.
Then, referring again to
With reference back to
The processor 16 of the winterization control unit 14 is programmed to execute a system start-up, which can start with the gate valve 19 controlling the water supply 18 being turned back on at step 558. Next, in step 560, the winterization control unit 14 indicates that the normal irrigation operation mode has been turned on. The winterization control unit 14 can include a visual indicator in the form of an LED light or an on-screen message that indicates whether the normal irrigation mode is on or off.
The system start-up is preferably performed such that the liquid antifreeze 105 is purged from the system 10 slowly at reduced pressures to avoid aspiration of the liquid antifreeze 105 into the surrounding air. Referring to
While the antifreeze solution is being flushed from the system 10, the winterization control unit 14 is programmed to determine whether a pressure signal has been received from the pressure sensor 28. If at step 568, the winterization control unit 14 determines that the pressure signal has not yet been received from the pressure sensor 28, the winterization control unit 14 continues to flush the liquid antifreeze 105 from the selected zone 22a (as indicated by the arrow looping back from step 568 to step 566). If, on the other hand, the winterization control unit 14 determines at step 568 that the pressure signal has been received from the pressure sensor 28, the winterization control unit 14 sends a signal that causes the pressure reducing valve 48 to fully open and to run the selected zone 22a for a predetermined period of time, for example, 30 seconds. It will be understood that 30 seconds has been selected by way of example only, and that any other suitable time interval can be used, for example, 20 seconds, 45 seconds, one minute, 2 minutes, or more.
In step 572, the flow sensor 41 measures the flow in the selected zone 22a and determines whether the flow is as expected by checking the measured flow rate against flow rate values stored in the memory 20 of the winterization control unit 14. If the flow sensor 41 sends information to the winterization control unit 14 that the flow in the selected zone 22a is not as expected (e.g., unexpected flow fluctuations are present), or if a leak in the main line 15 is detected, the winterization control unit 14 is programmed to send a signal (e.g., a power signal or a data signal) that shuts down the system 10 in step 574. In one approach, the winterization control unit 14 includes an audible alarm that indicates that the flow rate is too high or too low. Then, at step 576, the winterization control unit 14 remains in shutdown mode until an input is received from the user that the zone where the flow rate was too low or too high, or where the leak was detected, has been repaired. Once such an input or signal indicating that repair has been completed is received at step 576, the winterization control unit 14 proceeds to flush the antifreeze solution from the remaining zones as steps 566-572 are repeated.
If, in step 572, the flow sensor 41 sends information to the winterization control unit 14 that the flow in the selected zone 22a is as expected, the winterization control unit 14 continues to cause the antifreeze solution to be purged from the selected zone 22a. The lateral zones 22a, 22b, and 22c are preferably purged sequentially. At step 578, a pressure reading signal from the pressure sensor 28 attached to the main line 15 is sent to the winterization control unit 14. When this signal is received from the pressure sensor 28, the processor 16 of the winterization control unit 14 interprets it to determine whether the last zone has been purged of the antifreeze solution. If the winterization control unit 14 determines, based on the received pressure signal, that not all zones have been purged yet, the winterization control unit 14 proceeds to flush the antifreeze solution from an appropriate zone and the steps 566-578 are repeated. If, on the other hand, the winterization control unit 14 determines that all zones have been purged, the winterization control unit 14 proceeds to relinquish control of the irrigation system 10 to the main irrigation controller 12 and enters standby mode until the next winterization cycle.
With reference to
In one approach depicted in step 602, the outputting of the signal by the winterization control unit in step 608 can be in response to receiving, at the winterization control unit, at least one of air and water temperature data from at least one sensor, for example one or more of sensors (e.g., sensors 28, 32, 36). In one approach shown in step 604, the outputting of the signal by the winterization control unit in step 608 can be in response to a determination, at the winterization control unit, that the air and/or water temperatures received from the temperature sensors (e.g., sensors 32 and/or 36) are exhibiting a trend that is approaching a predetermined temperature threshold. The predetermined temperature threshold can be, for example, a minimum acceptable temperature for the system to be in normal irrigation operation. As described above, the minimum acceptable temperature can be stored in the memory of the winterization control unit.
In another approach depicted in step 606, the outputting of the signal by the winterization control unit in step 608 can be in response to receiving a manual user input, for example, a command to initialize the winterization cycle. As described above, the user input to initialize the winterization cycle can be provided at the location of the winterization control unit (e.g., by manual manipulation of the user interface 228) or via a wired or wireless connection from a remote location such a central station or a central controller. In a variation of step 606, the manual user input resulting the outputting of the signal by the winterization control unit in step 608 can be a calendar date (triggering the start-up of the winterization) previously entered or selected through manual user input by the user into the winterization control unit 14, where the reaching of the stored calendar date triggers the outputting of the signal.
In some embodiments, steps 602 and 604 and/or 606 and/or variations can be considered to result in a generic step of determining by the winterization control unit that winterization of the irrigation system is to be initiated (activated) or deactivated, which then leads to the performance of step 608.
In step 610, the signal that is output by the winterization control unit in step 608 is received at the antifreeze supply unit (e.g., antifreeze supply unit 100). As discussed above, the signal sent by the winterization control unit to the antifreeze supply unit can be an electrical signal (e.g., an A/C power signal) and/or a data signal that is sent via a wired connection or wirelessly. In one approach, the antifreeze supply unit can include logic circuitry adapted to interpret the signal received from the winterization control unit. For example, such logic circuitry can be implemented into or coupled to a pump (e.g., pump 106) that forms a part of the antifreeze supply unit and which is coupled to the antifreeze storage container (e.g., container 104).
Next, the method includes injecting, responsive to the signal, at least some of the liquid antifreeze 105 from the antifreeze storage container 104 of the antifreeze supply unit 100 into the water line (e.g., water line 15) (step 612). As discussed above, the injecting step 612 may include activating the pump (e.g., pump 106) of the antifreeze supply unit 100 to initiate the injection of the liquid antifreeze 105 from the antifreeze storage container 104 via a connection (e.g., connection 44) into the main water line 15. In one approach, the antifreeze supply unit 100 may lack the pump 106 and the antifreeze storage container 104 of the antifreeze supply unit 100 may be a pressurized container that can inject the antifreeze solution 105 into the connection 44 and the main water line 15 when a valve (not shown) coupled to the pressurized container is opened in response to the signal (e.g., a power signal and/or a data signal) received at the antifreeze supply unit 100 from the winterization control unit 114. Some embodiments of the exemplary automatic irrigation freeze protection system 10 described above have advantages over currently known systems at least because they eliminate the need for homeowners to schedule winterization service calls and save the homeowners operation costs and aggravation of being dependent on the availability of a service person to winterize their irrigation systems should the need arise.
As described above, in some embodiments, the winterization control unit 114 outputs an additional signal to terminate the injection of the liquid antifreeze 105 into the main line 15. For example, in some cases, the liquid antifreeze 105 is injected for a specific length of time or until a certain pressure in the main line 15 is obtained. In some embodiments, an output from the winterization control unit 114 is not needed in order to terminate the injection. For example, the antifreeze supply unit (e.g., unit 100) is configured to inject antifreeze solution for a predefined length of time.
By eliminating the need to schedule a winterization service call with an irrigation system contractor, the homeowner or the light commercial property owner is assured that the automatic irrigation system 10 is being winterized at the optimal time each and every year without having to be concerned whether the system 10 has been exposed to extreme cold temperatures which could have resulted in freeze damage to the system 10. In addition, the system 10 utilizes a much safer and effective means of providing freeze protection to the automatic irrigation system by winterizing and spring actuation of the system at lower pressures and flow rates.
While the invention herein disclosed has been described by means of specific embodiments, examples and applications thereof, numerous modifications and variations could be made thereto by those skilled in the art without departing from the scope of the invention set forth in the claims.
