AU2014203806B2 - Sensor and System including a Sensor - Google Patents

Abstract

-17 Abstract In one aspect, there is provided a sensor for detecting a level of a liquid in a vessel, the level of the liquid moving between a filled condition and a dry condition, the sensor including: a body including a receptacle; a first opening arranged to allow fluid communication between the receptacle and the liquid contained in the vessel; a second opening arranged to allow fluid communication between the receptacle and the external environment; and wherein the second opening is adapted to be selectively movable between an open state in the dry condition, and a closed state in the filled condition; and wherein in the dry condition, the second opening is in the open state so as to allow the liquid to enter receptacle via the first opening and displace gas within the receptacle via the second opening; and wherein in the filled condition, the second opening moves to the closed state such that the receptacle provides a seal between the second opening and the liquid within the receptacle. 24 25 10 16 4 Figure 1 29 35 36 48 26 33 - - 44 39 Figure 2 Figure 3

Description

-1 SENSOR AND SYSTEM INCLUDING A SENSOR Technical Field [001] The invention relates to a sensor and system including a sensor. More specifically, the invention relates to a fluid level sensor and a watering system including a fluid level sensor. Background [002] Watering systems are often used to automate the supply of water to plants. Typically, such systems include a timer connected to a flow control device which is fitted to a water supply. The timer may be programmed to selectively open the flow control device so as to allow water to flow from the supply to the plants. [003] It is well known that plants need to be watered on a regular basis to promote growth and the well-being of the plant. However, if the plant is overwatered there may be a detrimental effect on the health of the plant such as the rotting of the roots. [004] When a timer based water system is used, the plant may be watered at the preselected time intervals irrespective of whether there has been any natural rainfall, or whether or not the plant requires water. [005] Accordingly, a disadvantage of these watering systems is the lack of feedback to the watering system in relation to the water requirements of the plant. [006] The invention described herein seeks to overcome one or more of the above mentioned disadvantages or at least provide a useful alternative. Summary [007] In accordance with a first aspect there is provided, a sensor for detecting a level of a liquid in a vessel, the level of the liquid moving between a filled condition and a dry condition, the sensor including: a body including a receptacle; a first -2 opening arranged to allow fluid communication between the receptacle and the liquid contained in the vessel; a second opening arranged to allow fluid communication between the receptacle and an external environment; and wherein the second opening is adapted to be selectively movable between an open state in the dry condition, and a closed state in the filled condition; and wherein in the dry condition, the second opening is in the open state so as to allow the liquid to enter receptacle via the first opening and displace gas within the receptacle via the second opening; and wherein in the filled condition, the level of the liquid within the receptacle is at a filled level and the second opening moves to the closed state such that the receptacle is sealed between the second opening and the liquid within the receptacle and the body is adapted so that as the level of the liquid in the vessel moves from the filled condition to the dry condition, the level of the liquid within the receptacle is at least temporally maintained toward the filled level. [008] In one form, the body includes the first opening leading to the receptacle, first opening being shaped to provide a water tension seal between the receptacle and the vessel, the water tension seal being breakable when the vessel is in the dry condition thereby allowing the liquid within the receptacle fall to an emptied level. [009] In another form, the sensor includes a level sensor and the second opening includes a fluid control device in communication with the level sensor, wherein the level sensor is configured to detect the liquid level within the receptacle so as to allow the fluid control device to move between the open state at the emptied level, and the closed state at the filled level. [0010] In another form, the fluid control device is an air solenoid valve. [0011] In another form, the level sensor is configured for communication with a further liquid control device, the liquid control device being fitted to a liquid supply so as to allow selective filling of the vessel when the level sensor detects the receptacle is at the emptied level. [0012] In another form, the further liquid control device is a water solenoid valve.

-3 [0013] In another form, the body is a container, the container including the first opening at a first end, the second opening at the second end and at least one side wall extending between the first and second ends so as to define the receptacle. [0014] In another form, the at least one sidewall includes a flange arranged to be seated in use against an inside surface of the vessel so as to provide a water tension seal between the container and vessel. [0015] In another form, the container includes at least two opposing side walls and the flange is provided in the form of inward facing wings extending along each of the opposing side walls. [0016] In another form, the flange is arranged to skirt the at least one sidewall. [0017] In another form, the container is self-supporting so as to stand vertically from vessel. [0018] In another aspect there is provided, a watering system including a sensor as described above, the watering system including a control unit and a water control device in electrical communication with the sensor, the water control device being fitted to a water supply conduit to selectively supply water in response to a signal from at least one of the sensor and control unit. [0019] In accordance with another aspect there is provided, a watering system including a sensor as described above, the watering system including a solar panel and a water control device in electrical communication with the sensor, the solar panel being configured to power the sensor and the water control device, and the water control device being fitted to a water supply conduit to selectively supply water in response to a signal from the sensor. [0020] In accordance with another aspect there is provided, a kit including a watering system as described above, the kit including a tray in which the senor and a plant are receivable.

-4 [0021] In one example, the tray includes a drain adapted to slowly drain water from the tray. Brief Description of the Figures [0022] The invention is described, by way of non-limiting example only, by reference to the accompanying figures, in which; [0023] Figure 1 is a side view illustrating a watering system including a sensor located within a vessel; [0024] Figure 2 is a side view illustrating the sensor; [0025] Figure 3 is a top view illustrating the sensor; [0026] Figure 4 is a side view illustrating a second example of the sensor; [0027] Figure 5 is a top view illustrating the second example of the sensor; [0028] Figure 6a is a side view illustrating the vessel in a dry condition and the sensor at an emptied level; [0029] Figure 6b is another a side view illustrating the vessel being filled between the dry condition and the filled condition; [0030] Figure 6c is another a side view illustrating the vessel being drained between the filled condition and dry condition; [0031] Figure 6d is another a side view illustrating the vessel being substantially drained toward the dry condition with the water level in the sensor being at least temporarily maintained at a full level; [0032] Figure 7a is a schematic diagram showing connections between the sensor, control and power components and a water solenoid valve; and -5 [0033] Figure 7b is a schematic diagram showing connections between the sensor, the water solenoid valve and a solar panel. Detailed Description [0034] Referring to Figure 1, there is shown a sensor 10 for detecting a level of a liquid in a vessel 12. The sensor 10 may be provided in isolation or as part of a watering system 20 as is shown in Figure 1. [0035] The vessel 12 may be in the form of a tray 14, such as a plastic tray, in which a plant 16 and/or a potted plant is 18 may be received. The vessel 12 is adapted to contain a fluid, such as water, which is used to hydrate the plant 16 and/or soil of the potted plant 18. [0036] The level of the liquid within the vessel 12 may be controlled by the watering system 20 to move between a filled condition in which the liquid is at a high water mark (HW) and a dry condition in which the liquid is substantially drained and/or dried, such as by evaporation, from the vessel 12. [0037] The sensor 10 includes: a housing body 22 including a receptacle 24; a first opening 25 arranged to allow fluid communication between the receptacle 24 and the liquid contained in the vessel 12; and a second opening 26 arranged to allow fluid communication between the receptacle and the external environment. [0038] The second opening 26 is adapted to be selectively movable, between an open state in the dry condition, and a closed state in the filled condition. In this example, the second opening 26 includes a fluid control device 30 which is configured to move the opening between the open state and the closed state. [0039] The sensor 10 includes a level sensor 28 in communication with the fluid control device 30. The fluid control device 30 may be provided in a variety of forms including an air valve which may be self actuated or electrically actuated. In this example, the fluid control device 30 is provided in the form of an air solenoid valve -6 36. The air solenoid valve 36 is in electrical communication with the level sensor 28 either directly or indirectly via a control unit 34. The air solenoid valve 36 may be an IS09001 Brass 12V 1/4" Electric Solenoid Valve which may be varied depending on the electrical configuration of the system. [0040] The level sensor 28 is configured to detect the liquid level within the receptacle 24. The liquid level within the receptacle 24 may be different to the liquid level within the vessel 12. The liquid level within the receptacle 24 may move between a filled level and an emptied level and the level sensor 28 is configured to detect these levels so as to allow the fluid control device 30 to move between the open state in the emptied condition, and the closed state in the filled condition. [0041] More specifically, the level sensor 28 controls the electrical current flow to the air solenoid valve 36 such that movement of the level sensor 28 between the full level and the emptied level activates and deactivates the air solenoid valve 36 thereby allowing air to pass through the second opening 26. [0042] In this example, the level sensor 28 may be in the form of a horizontal or side mounted float switch 29. Theses type of sensors are commonly available and are not described in detail herein. However, in general terms these types of sensors include an articulated sensor body 31 having a first portion 33 connected to the body 22 and second portion 33 having a float 23. The first and second portions 33, 35 are pivotally connected to one another. There are electrical contacts between the first portion 33 and the second portion 35 which change state when the first portion 33 and second portion 35 are moved from a first position substantially in line with one another to a second position in which the first portion and second portion are angled relative to one another and/or substantially perpendicular to one another. Accordingly, the float is pivotally raised when liquid fills the receptacle and this in turn changes the electrical state of the level sensor 28 thereby communicating the level in the receptacle 24 to other components of the system such as the air solenoid valve 36. The level sensor 28 may also be provided in the form of a vertical float switch 37 which is further described in relation to Figures 4 and 5 below.

-7 [0043] The watering system 20 also includes a water solenoid valve 40 in electrical communication with the sensor 10. The water solenoid valve 40 is in electrical communication with at least one of the level sensor 28, control unit 34 and the air solenoid valve 36. The water solenoid 40 may be fitted to a pressurised water supply conduit which in this example is provided in the form of a pipe 42. When the water solenoid 40 is opened the water flows through the pipe 42 and into the potted plant 18. The pipe 42 may also be arranged to deliver the water directly into the vessel 12. The water solenoid valve 40 may be a Ehcotech - 1/2" Electric Solenoid Valve NSF61 Potable Water 12VDC 24VDC/VAC 110/120VAC G28E - which may be varied depending on the configuration electrical configuration. [0044] The tray 14 may be fitted with a slow-release drain 27. This ensures that the water level in the tray 14 does not permanently remain at the high water level and assists to inhibit soaking of the roots of the plant 16. The drain 27 is located at a relatively small height above the bottom surface of the tray 14 such that once the water has drained to the level of the drain 27 only a relatively shallow bath of water remains in the bottom of the tray 14. This shallow bath of water may be readily evaporated to the surrounding environment and, as will be further detailed below, trigger a new watering cycle to begin. [0045] Referring now to Figures 2 and 3, the sensor 10 is shown in more detail. The body 22 may be provided as a cylindrical container 44. The container 44 includes a first end or base 46 which provides the first opening 25 and a second end or top 48 which provides the second opening 26. A sidewall 39 extends between the first end 46 and the second end 48. The receptacle 24 is provided by an internal volume 50 of the container 44 between the first end 46 and the second end 48. [0046] The first end 46 includes a skirting flange 52 which in use is seated against an inside surface of the vessel 12. The skirting flange 52 is dimensioned to project laterally outwardly from the container 44 so as to provide a substantially flat disc shaped contact surface area with the inside surface of the vessel 12. As will be further detailed below, in use the shape and configuration of the skirting flange 52 assists to provide a water tension seal between the container 44 and the inside surface of the -8 vessel 12. The length of the skirting flange 52 may be about 10mm, the height of the container 44 may be about 50mm and the diameter may be about 50 mm to 70 mm. [0047] The container 44 may be formed of any suitable material which allows the container 44 to be self supporting and able to stand vertically from the container 44. Importantly, the container 44 should also be able to withstand a negative pressure within the receptacle 24. Such suitable materials may include metals and plastics. In this example, the container 44 is formed from brass. [0048] In this example, the first and second openings 25, 26 are shown at opposing ends 46, 48 of the container 44. However, other configurations of similar openings and conduits may also be utilised. For example, the second opening 26 may be provided on the sidewall 39 of the container 44 and the second opening 26 could be provided by series of conduits located at the first end 46 of the container 44. [0049] Referring now to Figures 4 and 5, there is shown a second example of the sensor 10 in which like numerals denote like parts. In this example, the body 22 of the sensor 10 is provided in the form of a square or rectangular shaped container 47 in and the level sensor 28 is provided in the form of vertical float switch 37 which is fitted to the top 48 of the body 22. In this example, the first and second openings 25, 26 are also shown at opposing ends 46, 48 of the container 47. [0050] The body 22 includes four sidewalls 39 including a first pair of opposing sidewalls 41 and a second pair of opposing sidewalls 43. The first set of opposing sidewalls 41 include the inward facing flanges 52 or wings 45 and the second set of opposing side walls 43 simply terminate with a straight edge 49. The receptacle 24 is provided by the internal volume 50 of the container 44 between the first end 46 and the second end 48. [0051] In this example, the housing body 22 may be constructed from 0.8 mm brass plate. Dimensions of the housing body 22 may include a length "L" of about 70 mm, a width about "W" of 50mm and a height "H" of about 50mm. other variations of the housing body 22 may have different dimensions. Unlike the first example of the housing body 22, in this example the flanges 52 are inward facing to provide wings 45 -9 extend only a long the first set of opposing sidewalls 41 which are provided on the long axis of the housing body 22. This assists with the ease of construction and to make the overall dimensions of the sensor 10 smaller. Having the inward facing wings 45 on only two sides of the housing body 22 provides adequate sealing to retain a water tension seal between the container 47 and the inside surface of the vessel 12. The length of the wings 45 is about 10mm. [0052] The air solenoid valve 36 is configured in a similar manner to that described above in relation to the first example of the sensor 10 and is fitted to the top 48 of the body 22 alongside the vertical float switch 37. The vertical float switch 37 is commonly available type and is not described in detail herein. However, in general terms, these type of vertical float switches 37 include a float 51 and a sensing stem or rod 53 which including magnetic components and a reed switch configured to provide an electrical signal when the float 51 moves vertically on the sensing stem 53 thereby providing the electrical signal as to the water level with the receptacle 24 of the sensor 10. One suitable switch is the Mini Stainless Steel Float Level Switch Model No. SSF-09. The vertical float switch 37 is sealed with the top 48 of the body 22 so as to be airtight and extends downwardly into the receptacle 24 so that the float 51 is contactable with the water in use. In this example, the water solenoid valve 40 may be a N/C 12V DC 1/2" Electric Solenoid Valve which may be varied depending on the configuration electrical configuration. [0053] Referring now to Figures 6a to 6d, the operation of the watering system 20, in particular, the operation of the sensor 10 is shown in more detail. It is noted that the sensor 10 illustrated is the first example as described in Figures 2 and 3. However, the second example of the sensor 10 as described in relation to Figures 4 and 5 may also be used. [0054] Beginning with Figure 6a, the fluid level in the vessel 12 is shown in a dry condition in which the fluid is substantially drained from the vessel 12. The level within the receptacle 24 is at an emptied level. In this condition, the level sensor 28 is in a lowered on position which causes the air solenoid valve 36 to move the second opening 26 to the open state. The level sensor 28 being in the lowered position also -10 causes the water solenoid valve 40 to open which allows water to flow via the conduit 42 into the vessel 12. [0055] Referring now to Figure 6b, the vessel is shown in a partially filled state between the dry condition and the filled condition. In this intermediate filling state the air solenoid valve 36 is open and the water solenoid valve 40 is open. Liquid from the vessel 12 enters the receptacle 24 via the first opening 25 and the liquid level inside the receptacle 24 begins to rise. In this intermediate filling state, the liquid level inside the receptacle 24 is generally similar to that within the vessel 12. [0056] As the liquid level within the receptacle 24 rises a gas, more specifically air, is displaced by the rising liquid level and the gas escapes, as shown by arrow A, through the second opening 26 which is in an open state as controlled by the air solenoid valve 36. The second opening 26 needs to be sufficiently large to allow the gas to escape at a sufficient rate to prevent the container 44 from becoming buoyant. [0057] Referring to Figure 6c, the liquid level within vessel is shown in the filled condition and the receptacle 24 of the sensor 10 is shown at a full level in which the liquid level within the vessel 12 and the receptacle 24 are substantially equal. At the full level, the level sensor 28 moves into an off position which closes the water solenoid valve 40 and closes the air solenoid valve 36. The watering system 20 now remains in a standby mode and the water slowly drains via the drain valve 27 or is otherwise utilised by the plant 16 or lost to the surrounding environment by evaporation. [0058] Referring to Figure 6d, the liquid level within the vessel 12 is shown in a partially drained condition between the filled condition and the dry condition. In this condition the liquid level within the receptacle 24 of the sensor 10 is at least temporarily maintained at the full level. This is achieved by both the sealing between the second opening 26 and the liquid level within the receptacle 24 and the water tension seal provided between the flange 52 and the vessel 12. [0059] More specifically, as the liquid level in the vessel 12 drops a negative pressure develops in a void between the closed second opening 26 and the surface of the liquid -11 within the receptacle 24. This negative pressure creates a resultant force which urges the container 44, more specifically the flange 52, against the inside surface of the vessel 12. The water captured between the flange 52 and the inside surface of the container 44 assists to seal the fluid at the full level within the receptacle 24. [0060] Once the fluid within the vessel 12 becomes substantially drained or dried out the water captured between the flange 52 and the inside surface of the container 44 is drawn out which breaks the water tension seal and allows the liquid to flow out of the receptacle 24 into the vessel 12. This causes the liquid level within the receptacle 24 to move from the full level to the emptied level which in turn causes the level sensor 28 to return to the on position as is shown in Figure 6a. This again initiates a filling cycle of the watering system 20 in which the air solenoid valve 36 and the water solenoid valve 40 are open. [0061] Accordingly, in view of the above it may be appreciated that the watering system 20, in particular the sensor 10, allows the liquid to slowly drain from the vessel 12 and substantially dry out before refilling the vessel 12. This allows the water level in the vessel 12 to naturally fall over an extended period of time and become relatively dry before being refilled. This reduces the risk of the plant becoming exposed to overwatering and more closely resembles the natural water cycle that the plant is exposed to. Furthermore, if the plant 16 and the vessel 20 are exposed to rainfall or another water source which naturally refills the vessel 12, the sensor 10 will delay triggering the watering system 20 into a refilling cycle. [0062] Referring now to Figure 7a, a schematic of the watering system 20 is provided which shows the control unit 34 in more detail along with the electrical connections between the control unit 34, the water solenoid 40, the air solenoid 36 and the level sensor 28. In this example, the control unit 34 is relatively simple and includes a relay 60, a switch 62 and a battery 64. The switch 62 may be a hand operated switch used to toggle the watering system 20 between an on state and an off state. In the on state, the switch 62 completes the electrical circuit to the float switch 28. [0063] Accordingly, when the float switch 28 is moved to an on state, the float switch 28 provides an electrical signal to both the air solenoid 36 and water solenoid 40 -12 thereby moving both of these likewise to an on or open state. Similarly, when the full level is reached within the sensor 10, the level sensor 28 moves to an off state which in turn moves the water solenoid 40 and the air solenoid 36 to closed or off states. [0064] Other methods and configurations for controlling and connecting the system may also be apparent to a person skilled in the art. For example, the battery 64 may be removed from the system replaced with a solar panel, as is described below with reference to Figure 7b. Alternatively, a solar panel may be added to the system which charges the battery 64. The relay 60 may also be removed from the circuit provided the current and voltage of the components are appropriately matched and/or configured. [0065] Figure 7b shows a second example whereby the watering system 20 includes a solar panel 70 which directly powers the float switch 28, the air solenoid valve 36 and the water solenoid 40. In this configuration, the float switch 28, the air solenoid valve 36 and the water solenoid 40 are only powered when the solar panel 70 is generating current which occurs when there is sunlight incident on the solar panel 70. This has been found to be a suitable configuration as watering is most often required when the sun is shining. However, whilst this is a simple configuration, in some situations the system 20 may further include the battery 64 and the solar panel 64 may be configured to charge the battery 64. The battery 64 may power the system 20 in a similar arrangement to that described above in relation to Figure 7a. [0066] In this example, the solar panel 70 may be a typical 10 Watt solar panel and the float switch 28 and the air solenoid valve 26 are electrically matched with the solar panel 70 for suitable operation. Accordingly, when the float switch 28 is moved to an on state, the float switch 28 provides an electrical signal to both the air solenoid 36 and water solenoid 40 thereby moving both of these likewise to an on or open state. Similarly, when the full level is reached within the sensor 10, the level sensor 28 moves to an off state which in turn moves the water solenoid 40 and the air solenoid 36 to closed or off states. Due to the possible intermittent power, in this configuration, to the water solenoid 40 and the air solenoid 36 are configured to be in a normally closed state and only open when powered. As has been described about the electrical components such as the float switch 28, the air solenoid valve 36 and the water -13 solenoid 40 are all 12 volt, although the voltage of these components may be varied as required. The battery 64 as described above may be any suitable 12 volt battery. [0067] As may be appreciated from the above, there has been provided a watering system, in particular a sensor for a watering system, which advantageously allows a vessel, such as a tray in which a plant such as a potted plant is located, to only be refilled with water as required by the plant. In particular, the sensor is advantageously configured to allow the water level in the tray to substantially become dry before triggering a watering cycle to refill the tray. This assists to alleviate problems associated with overwatering plants and provides a watering system which is responsive to the natural water cycle including rainfall and evaporation. [0068] The reference in this specification to any known matter or any prior publication is not, and should not be taken to be, an acknowledgment or admission or suggestion that the known matter or prior art publication forms part of the common general knowledge in the field to which this specification relates. [0069] While specific examples of the invention have been described, it will be understood that the invention extends to alternative combinations of the features disclosed or evident from the disclosure provided herein. [0070] Many and various modifications will be apparent to those skilled in the art without departing from the scope of the invention disclosed or evident from the disclosure provided herein.

Claims (15)

1. A sensor for detecting a level of a liquid in a vessel, the level of the liquid moving between a filled condition and a dry condition, the sensor including: a body including a receptacle; a first opening arranged to allow fluid communication between the receptacle and the liquid contained in the vessel; a second opening arranged to allow fluid communication between the receptacle and an external environment; and wherein the second opening is adapted to be selectively movable between an open state in the dry condition, and a closed state in the filled condition; and wherein in the dry condition, the second opening is in the open state so as to allow the liquid to enter receptacle via the first opening and displace gas within the receptacle via the second opening; and wherein in the filled condition, the level of the liquid within the receptacle is at a filled level and the second opening moves to the closed state such that the receptacle is sealed between the second opening and the liquid within the receptacle and the body is adapted so that as the level of the liquid in the vessel moves from the filled condition to the dry condition, the level of the liquid within the receptacle is at least temporally maintained toward the filled level.

2. The sensor according to claim 1, wherein the body includes the first opening leading to the receptacle, the first opening being shaped to provide a water tension seal between the receptacle and the vessel, the water tension seal being breakable when the vessel is in the dry condition thereby allowing the liquid within the receptacle fall to an emptied level.

3. The sensor according to claim 2, wherein the sensor includes a level sensor and the second opening includes a fluid control device in communication with the level sensor, wherein the level sensor is configured to detect the liquid level within the receptacle so as to allow the fluid control device to move the second opening between the open state at the emptied level, and the closed state at the filled level. -15

4. The sensor according to claim 3, wherein the fluid control device is an air solenoid valve.

5. The sensor according to claim 3 or claim 4, wherein the level sensor is configured for communication with a further liquid control device, the liquid control device being fitted to a liquid supply so as to allow selective filling of the vessel when the level sensor detects the receptacle is at the emptied level.

6. The sensor according to claim 5, wherein the further liquid control device is a water solenoid valve.

7. The sensor according to claim 2, wherein the body is a container, the container including the first opening at a first end, the second opening at a second end and at least one side wall extending between the first and second ends so as to define the receptacle.

8. The sensor according to claim 7, wherein the at least one sidewall includes a flange arranged to be seated in use against an inside surface of the vessel so as to provide the water tension seal between the container and vessel.

9. The sensor according to claim 8, wherein the container includes at least two opposing sidewalls and the flange is provided in the form of inward facing wings extending along each of the opposing sidewalls.

10. The sensor according to claim 8, wherein the flange is arranged to skirt the at least one sidewall.

11. The sensor according to any one of claims 8 to 10, wherein the container is self supporting so as to stand vertically from vessel.

12. A watering system including a sensor as defined in any one of the previous claims, the watering system including a control unit and a water control device in electrical communication with the sensor, the water control device being fitted to a -16 water supply conduit to selectively supply water in response to a signal from at least one of the sensor and control unit.

13. A watering system including a sensor as defined in any one of claims I to 11, the watering system including a solar panel and a water control device in electrical communication with the sensor, the solar panel being configured to power the sensor and the water control device, and the water control device being fitted to a water supply conduit to selectively supply water in response to a signal from the sensor.

14. A kit including a watering system as defined in claim 12 or claim 13, the kit including a tray in which the senor and a plant are receivable.

15. The kit according to claim 14, wherein the tray includes a drain adapted to slowly drain water from the tray.