Abstract:
A self-watering plant container for a flower pot. The container base defines a cavity for holding the flower pot and an interior chamber for retaining water therein. The base has a first aperture in its outer wall that opens into the chamber and water is introduced therethrough. A plug seals the same. A channel extends between the chamber and cavity allowing water to flow therebetween. Water accumulates in the cavity and flows through openings in the bottom of the flower pot. The base includes a second aperture through which a hollow tube extends into the chamber. The tube provides a mechanism for bringing the system into equilibrium by permitting atmospheric air pressure to balance the water levels in the chamber and cavity. The container includes an electronic sensor that transmits a signal to a remote electronic device to indicate when water must be added to the container.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Technical Field 
         [0002]    This invention generally relates to gardening. More particularly, the invention relates to plant containers. Specifically, the invention relates to a self-watering plant container that includes a water retaining chamber having a tube inserted therein to allow for atmospheric regulation of the water level in the chamber and in an adjacent flower pot-retaining cavity in the container. 
         [0003]    2. Background Information 
         [0004]    The common and basic approach to watering plants is to do so in timely intervals, adding water manually to either the surface of the soil or to a water trap positioned beneath the container. At the time of watering, the soil is soaked to the point of saturation. Water is gradually withdrawn from the soil by the plant and additional water evaporates from the soil into the air. After several days, the soil drys out and then the over-saturated watering takes place yet again. The watering and drying cycles tend to shock the plant in the container and reduces the chances of the plant flourishing. It would be preferable to have a system in which a constant level of hydration is experienced. That way, the plant has a steady supply of water from which to draw and does not experience the cyclical shock of over-watering followed by drought. 
         [0005]    Several prior art patents have addressed this issue and have disclosed a variety of self-watering plant containers. One such device is disclosed in U.S. Pat. No. 4,219,967 issued to Hickerson. Hickerson discloses a base having a liquid retaining reservoir therein. A separate flower pot container is provided to interlock in a recess in the base. The flower pot container interlocks with a lip in the upper surface of the reservoir and extends upwardly and outwardly away from the upper surface of the reservoir. The flower pot container includes an aperture in its lower surface. An absorbent pad is provided. A first portion of the pad is retained within the reservoir in the base and a second portion of the pad rests on the interior surface of the flower pot container. A flower pot is received within the flower pot container and rests on the second portion of the pad. The first portion of the pad absorbs liquid from the reservoir and transmits the same to the second portion of the pad in the interior of the flower pot container. As the flower pot includes an opening in its bottom wall, water is transmitted from the second portion of the pad into the soil retained within the flower pot. The reservoir includes a lateral channel through which water may be introduced into the reservoir. 
         [0006]    U.S. Pat. No. 4,244,147 issued to Geddes discloses a flower pot holder that includes a base and a flower pot container retained within the base. The base includes a liquid reservoir. The flower pot container includes an enlarged opening in its bottom wall that is in communication with the reservoir. An absorbent pad is placed on the interior bottom wall of the container and between the interior bottom wall and a flower pot. A wick extends between the absorbent pad and the reservoir. The base is bulbous at its upper end, includes a narrow vertical section and a wider bottom support. The base includes a weight to ensure that the top-heavy base does not accidentally fall over. 
         [0007]    U.S. Pat. No. 4,343,109 issued to Holtkamp discloses a self-watering plant container. The container comprises a base that includes an open reservoir therein. Base further includes a shelf that is retained a spaced distance above the bottom interior surface of the base. The shelf is supported on a plurality of legs that extend downwardly to engage the bottom interior surface of the base. The upper surface of the shelf is provided with an absorbent pad. The upper surface of the shelf further includes an aperture therein. A portion of the absorbent pad is detached from the remainder of the pad and extends downwardly through the aperture and into liquid retained within the reservoir. As with the previously described flower pots, water travels up through the wick portion of the absorbent pad and saturates the pad resting on the shelf. A flower pot is positioned on the absorbent pad and water is transmitted through apertures in the base of the flower pot and into the soil retained therein. 
         [0008]    U.S. Pat. No. 4,932,159 issued to Holtkamp, Sr. discloses a wick insert that is placed into the opening in the bottom of a flower pot. A length of the wick insert extends outwardly from the opening and is placed into a reservoir. Liquid from the reservoir moves up the wick by capillary action and into the soil in the flower pot. 
         [0009]    Canadian Patent No. 2028721 issued to Cavallaro et al discloses an outer container which acts as a reservoir. An inner container is engaged with the outer container and is configured to retain the flower pot therein. The inner container has a hole in its base and a length of a wick is inserted through the hole and into the liquid retained in the outer container. A length of the wick is coiled and rests on the interior surface of the inner container. The flower pot is placed on top of the coiled wick and water moves through the wick and into the soil by capillary action. The inner container may also include an aperture in its upper surface for air circulation. 
         [0010]    Canadian Patent No. 2330059 issued to Lai discloses a flower pot container comprising a transparent outer wall and a concave inner wall. A soil holder is retained within the concave portion of the inner wall and the soil and plant are placed on an upper surface of the soil holder. A chamber for retaining water is defined between the inner and outer walls. The soil holder comprises a disk that has air vents extending through it and a plurality of water holes that extend between an upper and a lower chamber. The upper chambers of the soil holder retain a quantity of soil therein. The inner wall defines a hole through which a small tube is inserted. Water flows through the hole and tube from the chamber, into the lower chambers of the soil holder and then through the holes therein into the upper chambers of the soil holder. A float mechanism is attached to the tube to regulate the water flow into the inner pot and thereby controls the amount of water that is transmitted into the soil in the upper chambers of the soil holder. The outer and inner pots have nesting tubes to permit air to flow from the outside into the concave region of the inner wall and beneath the soil holder. 
         [0011]    There is therefore a need in the art for an improved self-watering plant container that is free of wicks and is regulated by the plant&#39;s consumption of water in the soil. 
       SUMMARY OF THE INVENTION 
       [0012]    The device of the present invention comprises a self-watering plant container for retaining a flower pot therein. The container includes a base defining a cavity for holding the flower pot therein. The base further defines an interior chamber for retaining a quantity of water and has a first aperture in its outer wall that opens into the chamber. Water is introduced into the chamber through the first aperture and a plug is used to seal the same. At least one channel extends between the chamber and the cavity to permit flow of water therebetween. Water accumulates in the bottom of the cavity and is able to flow into openings in the bottom end of the flower pot. The base also includes a second aperture through which an elongated hollow tube extends into the interior of the chamber. The end of the tube is disposed a spaced distance away from the interior bottom surface of the base. The tube provides a mechanism for bringing the system into equilibrium by permitting atmospheric air pressure to balance the water levels in the chamber and cavity. The container preferably includes an electronic sensor that transmits a signal to a remote electronic device to provide warning that the water level in the container has dropped below a preset value. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]    The preferred embodiments of the invention, illustrative of the best mode in which applicant has contemplated applying the principles, are set forth in the following description and are shown in the drawings and are particularly and distinctly pointed out and set forth in the appended claims. 
           [0014]      FIG. 1  is a perspective view of the self-watering plant container in accordance with the present invention; 
           [0015]      FIG. 2  is an exploded perspective view of the container of  FIG. 1 ; 
           [0016]      FIG. 3  is a cross-sectional front view of the container; 
           [0017]      FIG. 4  is an enlarged partial cross-sectional front view of the plant container showing the effect of atmospheric pressure through the tube; 
           [0018]      FIG. 5  is a cross-sectional front view of a second embodiment of a self-watering plant container in accordance with the present invention; 
           [0019]      FIG. 6  is a cross-sectional front view of a third embodiment of a self-watering plant container in accordance with the present invention; and 
           [0020]      FIG. 7  is a cross-sectional front view of a fourth embodiment of a self-watering plant container in accordance with the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0021]    Referring to  FIGS. 1-5 , there is shown a self-watering plant container in accordance with the present invention and generally indicated at  10 . Container  10  comprises an outer shell  12  and an inner shell  14 . Inner shell  14  is smaller than outer shell  12  and nests within outer shell  12 . Outer and inner shells  12 , 14  preferably are fabricated from a suitable thermoplastic polymeric material but can also be made from any other type of plastic, glass, acrylic, wood, ceramic, clay, metal etc. Furthermore, any of the component parts of container  10  may be made of clear or tinted plastic material or any color or combination of transparent, tinted or colored components. Furthermore, outer and inner shells  12 ,  14  may be of any desired shape included but not limited to cylindrical, conical, square, triangular and semicircular. 
         [0022]    Outer shell  12  comprises a bottom wall  16  with a peripheral side wall  18  extending upwardly away therefrom and terminating in an upper edge  20 . Bottom wall  16  and peripheral side wall  18  define and surround a chamber  2222  that is sized to receive inner shell  14  and to act as a reservoir for water  24 . A plurality of spacers  26  extend downwardly away from bottom wall  16 . Spacers  26  are adapted to rest upon a resting surface  28 , creating a gap  30  between bottom wall  16  and surface  28 . Gap  30  permits air to circulate beneath outer shell  12  and thereby keeping surface  28  dry and free of condensation. Spacers  26  preferably are an integral part of outer shell  12  and are of any shape and pattern, and may be disposed anywhere on bottom wall  16  that will enable outer shell  12  to be adequately supported on surface  28 . 
         [0023]    Inner shell  14  comprises a bottom wall  32  with a peripheral side wall  34  extending upwardly away therefrom. Side wall  34  preferably is frusto-conical in shape and terminates in a horizontally-oriented, annular first flange  36 . It will of course be understood that any other desired shape, such as a conical shape, may also be utilized. A vertically-oriented, annular second flange  38  extends upwardly from first flange  36  and terminates in an annular lip  40 . When inner shell  14  is nested into chamber  22  of outer shell  12 , lip  40  rests on upper edge  20  of outer shell  12 . Outer shell  12  may, alternatively rest on upper edge  20  or may interlock therewith. The engagement between outer shell  12  and inner shell  14  preferably is such that the connection permits the two components to be disassembled, yet when assembled provides an air tight connection between them. An appropriate sealant may also be applied between upper edge  20  and lip  40  to ensure this air tight connection. Inner shell  14  defines a cavity  42  that is shaped to receive a flower pot  44  therein. Flower pot  44  is a standard or regular flower pot of the type that includes an opening  45  in a bottom wall  47  thereof. Bottom wall  32  of inner shell  14  includes a plurality of raised ribs  46  that are separated from each other by depressions  48 . Ribs  46  may be of any suitable size and shape and are positioned so that flower pot  44  may rest thereon. 
         [0024]    Side wall  34  of inner shell  14  defines a plurality of channels  50  therein. Channels  50  extend directly between chamber  22  and cavity  42  and permit water  24  to flow between chamber  22  and cavity  42 . Depressions  48  ensure that water  24   a  in cavity  42  will flow into the region between bottom wall  32  of inner shell  14  and bottom wall  47  of flower pot  44 . The opening  45  in flower pot  44  allows water  24   a  from cavity  42  to seep into flower pot  44  and move upwardly in the soil  49  through capillary action. The roots of the plant  51  growing in soil  49  consume water from soil  49 . Opening  45  also allows water retained within soil  49  to seep out of flower pot  44  and into cavity  42  if flower pot  44  is watered directly into soil  49  and there is little to no water in chamber  22  and chamber  42 . 
         [0025]    The first flange  36  of inner shell  14  defines a first aperture  52  therein. A rim  54  preferably extends upwardly and outwardly from first flange  36  and surrounds first aperture  52 . A plug  56  is received in first aperture  52  to close off access to chamber  22 . Rim  54  provides a guide when filling with water and helps support plug  56  when inserted in first aperture  52 . First flange  36  further defines a second aperture  58  therein. An elongated, hollow tube  60  extends through second aperture  58  and into chamber  22  when inner and outer shells  14 , 12  are engaged with each other. Tube  60  has an upper end  60   a  that engages the exterior surface of first flange  36 . Upper end  60   a  is an annular lip but may be any suitable connection between first flange  36  and tube  60 . This connection must provide an airtight seal around the upper end  60   a  of tube  60 . Tube  60  has a second end  60   b  that is disposed within chamber  22  and is spaced a distance h 1  ( FIG. 4 ) from bottom wall  16  of outer shell  12 . Tube  60  includes a longitudinal bore  62  that acts as a passageway for air so that tube  60  functions as a breather in chamber  22 . Tube  60  terminates proximate the bottom wall  16  of outer shell  12  in a region that typically will be below the level of water retained in chamber  22 . Without tube  60 , chamber  22  would be substantially air tight and a vacuum effect would resist the flow of water through channels  50  from chamber  22  through to cavity  42 . Tube  60  permits atmospheric pressure to regulate the water levels in chamber  22  and cavity  42 . 
         [0026]    Container  10  may further be provided with a water level indicator of some suitable type. Outer shell  12  may include indicators  64  on side wall  18  thereof to indicate a maximum and a minimum water level in chamber  22 . The indicators  64   a ,  64   b  may take the form of a raised or colored line. Alternatively, or additionally, container  10  may include an electronic sensor and display  66  to measure and indicate the water level in chamber  22 . 
         [0027]    Container  10  is used in the following manner. Plug  56  is removed from first aperture  52 . Water is introduced through first aperture  52  and into chamber  22  until the water level  68  reaches the maximum water level indicator  64   a . Water will flow into bore  62  of tube  60  during filling of chamber  22 . Water level in cavity  42  will increase slightly during filling of chamber  22 . Once sufficient water has been added to container  10 , plug  56  is reinserted into first aperture  52  to seal access to chamber  22 . Water level  68  in chamber  22  is at a distance “h+h 1 ” ( FIG. 4 ) from bottom wall  16  of outer shell  12 . A quantity of water  24  from chamber  22  flows through apertures  50  in inner shell  14  and accumulates in cavity  42  to a height of h 2  from the bottom wall  16 . A lesser quantity of water flows from cavity  42  through opening  45  in flower pot  44  and into the soil  49 . The water rises upwardly through soil  49  by capillary action until the system reaches a state of equilibrium. 
         [0028]    The plant  51  withdraws water from the soil  49  in flower pot  44  and some of the water therein also evaporates. As water is consumed from soil  49  by plant  51  and by evaporation, the equilibrium in the system is disturbed and water is drawn slowly into the soil  49  from cavity  42 , and subsequently from chamber  22 . As this continues, the water level  68  is lowered in chamber  22  so that the size of h ( FIG. 4 ) decreases. This equilibrium disturbance will be maintained until the water level  68  in the chamber  22  drops below the second end  60   b  of tube  60 . During filling, the water level in chamber  22  will be equal to the water level in bore  62  of tube  60 . After plug  56  is reinserted, the water level in bore  62  decreases first and drops reaching the second end  60   b  of tube  60 . After water level in bore  60  reaches second end  60   b  of tube  60 , water consumption begins from water chamber  22  and water level is decreasing in chamber  22  due to water consumption by plant  51 . After water level  68  in chamber  22  drops below the second end  60   b  of tube  60  reaching h 1  ( FIG. 4 ) water level  68  and water level  24   a  will equalize, h 1 =h 2 . 
         [0029]    The length and dimensions of the bore  62  of tube  60  play a factor in the equilibrium of the system. The Applicant believes that the system operates using the principles of Bernoulli&#39;s equation. The hydrostatic equation is based on the assumption that as there is very slow water consumption by plant  51 , the rate of water flow through apertures  50  is sufficiently close enough to a standstill condition that in a given time period, such as  1  second, there is no water consumption inside cavity  42  of inner shell  14 . Based on this assumption and using the illustration of  FIG. 4 , the following equations apply: 
         [0030]    Pa=atmospheric pressure 
         [0031]    P=air pressure inside the chamber 
         [0032]    h, h 1 , h 2 =water column heights/hydrostatic pressure 
         [0033]    g=gravity 
         [0034]    μ=resistance in apertures and water surface strain 
         [0035]    ξ=water specific density 
         [0000]        Pa+ξ gh 2+μ= Pa+ξ gh 1   (1) 
         [0000]        Pa−ξ gh 1= P+ξ gh    (2) 
         [0036]    Due to plant water consumption, the quantity of water h 2  in cavity  42  is decreasing. This fact creates a condition when the equilibrium of equation (1) is disturbed. 
         [0000]        Pa+ξ gh 2+μ&lt; Pa+ξ gh 1 
         [0037]    Water  24  from the chamber  22  seeps through channels  50  and into cavity  42  of inner shell  14 . Simultaneously, air enters through tube  60  into chamber  22  until the conditions of equation (1) and (2) are not fulfilled and equilibrium is established again. Due to plant water consumption, this slow process will continue until the water level  68  reaches end  60   b  of tube  60 . 
         [0038]    It has been found through experiment that container system  10  functions well when bore  62  of tube  60  has an 8 mm inside diameter, the end  60   b  of tube  60  is disposed 7 mm above apertures  50 , and inner shell  14  has four apertures  50  that are each 2 mm in diameter. 
         [0039]    Sensor  66 , if provided, has a probe that extends through a third aperture in first flange  36  and into chamber  22  to monitor the water level  68  therein. When the water level  68  reaches a preset minimum amount, sensor  66  transmits a signal, such as an instant message, to a remote electronic device such as to a preset phone number. The message will indicate to the receiver that the water level in container  10  is low. The message may, of course, include any other pertinent information, such as which of several self-watering containers is transmitting the signal, how much water remains in the container etc. The message may be repeated at specified time intervals and for a preset time period. The message is repeated until container  10  is refilled or sensor  66  is disabled or cleared. This disablement or clearing can be done remotely from the preset phone number. 
         [0040]    Water dosage from this system is optimum at all times and is regulated by the plant&#39;s own water consumption. Water flows from chamber  22  into cavity  42  and directly into opening  50  in flower pot  44 . Container  10  does not utilize any intermediary such as a wick, soil stand or float mechanism to regulate water flow from chamber  22  into flower pot  44 . 
         [0041]    While the first preferred embodiment has been illustrated and described as an outer and inner shell that are joined to each other at the upper ends of the side walls it will be understood that outer and inner shells may be molded with blow-molding technology to form a single, integral, unitary member (not shown) with apertures  58 ,  52  and  50  formed therein. Furthermore, the bottom of the inner shell of such a unitary member may or may not be resting on the interior surface of the outer shell thereof. 
         [0042]    A second embodiment of a self-watering plant container in accordance with the present invention is shown in  FIG. 5  and generally indicated at  110 . The components of container  110  are substantially identical to those of container  10  with the exception that the outer and inner shells  112 ,  114  are molded with blow-molded technology to form a single, integral unitary unit  180  with apertures  58 ,  52  and  50  formed therein; and having a large opening at a bottom end thereof. A cap  182  is provided to close off the large opening, thereby closing off container  110  and creating a watertight chamber therein. Cap  182  interlockingly engages a bottom edge  184  of unit  180 . Spacers  126  are provided on a bottom surface of cap  182  and serve the same purpose as spacers  26  in container  10 . A probe from sensor  166  may extend through a third aperture in the upper surface of unit  180  and into the water chamber to monitor the level of water  168  therein. 
         [0043]    A third embodiment of a self-watering plant container in accordance with the present invention is shown in  FIG. 6  and generally indicated at  210 . The components of container  210  are substantially identical to those of either container  10  or container  110  (as illustrated) with the exception that the second aperture  258  is formed in plug  256 . Tube  260  is sealingly connected to the plug  256  and extends downwardly therefrom into the chamber  222  between outer shell  212  and inner shell  214 . Tube  260  terminates a spaced distance away from bottom wall  216  of container  210 . 
         [0044]    A fourth embodiment of a self-watering plant container in accordance with the present invention is shown in  FIG. 7  and is generally indicated at  310 . The inner and outer shells  314 ,  312  of container  310  may be joined together or integrally formed as previously described. Container  310 , however, also includes an additional aperture  370  defined in first flange  336 . Aperture  370  sealingly receives a check-valve  372  therein. Check-valve  372  functions as both a maximum water level indicator and as a water overflow valve. The plug  356  utilized in container  310  may also be provided with an aperture  358  therethrough and a filling valve  374  may be sealingly received through aperture  358 . A pressurized water source (not shown) may be connected to filling valve  374  to rapidly introduce water into chamber  322 . In this embodiment of the invention, water can alternatively be introduced into chamber  322  through tube  360  by attaching a pressurized water source to an adapter  376  engaged with tube  360 . 
         [0045]    It will be understood that container  10  does not need to retain a flower pot  44  but can instead have the soil  49  and plant  51  retained directly within cavity  42 . In this instance, it will be preferable to include a sponge type of material (not shown) resting on wall  32  so that apertures  40  do not become clogged with soil  49 . 
         [0046]    It will further be understood that apertures  52  and  58  may be formed anywhere on the outer surface of container  10  that will permit the device to function as described above. 
         [0047]    In the foregoing description, certain terms have been used for brevity, clearness, and understanding. No unnecessary limitations are to be implied therefrom beyond the requirement of the prior art because such terms are used for descriptive purposes and are intended to be broadly construed. 
         [0048]    Moreover, the description and illustration of the invention are an example and the invention is not limited to the exact details shown or described.