a plant watering apparatus , as shown in fig1 - 4 includes several features from applicant &# 39 ; s co - pending united states patent application ser . no . 870 , 849 , to be u . s . pat . no . 4 , 805 , 342 . the disclosure of this application and patent are herein incorporated fully by reference . the invention provides an apparatus which will supply a plant 10 with water at a substantially constant rate over an extended period of time . the plant 10 is typically potted in soil 14 contained by a suitable grow pot structure 18 . the invention provides a housing 20 which can be supported alongside the grow pot 18 . this can be accomplished by the hangers 24 which have downwardly opening hook portions 26 adapted to engage a top edge 28 of the grow pot 18 . a closed liquid reservoir 32 can be provided in the housing 20 and includes a means for introducing a liquid 34 into the liquid reservoir 32 . the liquid is usually water , but can also be other liquids and solutions necessary or helpful to plant growth . an opening 36 can be formed through which liquid can be introduced into the liquid reservoir 32 . a suitable neck structure 38 can extend outwardly from the opening 36 so as to provide a seat for closure structure such as the cap 40 . the cap 40 can engage the neck 38 by any suitable means , including cooperating threading , but preferably should form a substantially hermetic seal of the opening 36 . at least one outlet conduit 44 communicates with the liquid reservoir 32 through an outlet opening 48 . the outlet opening 48 will normally be positioned substantially at the bottom of the liquid reservoir 32 so as to provide for a more complete discharge of liquid 34 . a pressurization means is provided to apply a gas pressure to the liquid reservoir 32 . the gas pressurization means could comprise a bottled compressed gas , although a preferred structure is the gas compressor 52 which receives air through a gas inlet 54 and releases the air at a gas outlet 56 . one or more openings can be provided in the housing 20 if necessary to allow an adequate air flow into the compressor 52 . the compressor 52 is powered by a motor 60 which can receive energy from a suitable source , such as an electrical outlet . it is preferable , however , to provide a battery 62 which can be mounted within the housing 20 so as to make the apparatus completely portable . a gas accumulation tank 66 is preferably also provided for a more constant gas pressure and to avoid excessive cycling of the compressor 52 . gas is transferred from the gas outlet 56 of the compressor 52 to the tank 66 by a suitable gas transfer conduit 72 . gas exits the tank 66 through a second gas transfer conduit 68 , and is passed to the liquid reservoir 32 through an inlet opening 74 . the pressurized gas applies a pressure to the liquid 34 in the liquid reservoir 32 , which pressure forces the liquid through the outlet opening 48 and discharge conduit 44 . a pressure regulator 70 can be provided between the gas storage tank 66 and the liquid reservoir 32 , as in the second gas transfer conduit 72 , to reduce the pressure of the gas reaching the liquid reservoir 32 to a desired value . an adjustment knob 71 can be utilized to increase or decrease the pressure reaching the liquid reservoir 32 , as desired . it will be understood that an increased gas pressure will generally lead to an increased liquid flow rate through the discharge conduit 44 , and that a decreased pressure will result in a decreased liquid flow rate . a presently preferred pressure is between about one - half psig and about three - fourths psig . structure is preferably provided for regulating the flow of liquid through the discharge conduit 44 . this structure can include one or more discharge openings 78 which can be formed in various small dimensions to prevent the rapid release of water . the discharge openings can be formed in the sides of the conduit 44 or in a suitable nozzle 79 as shown . one suitable method of forming the discharge openings 78 would be to use laser technology to create very small and precise discharge openings . additionally , regulating structure such as a needle valve 82 can be provided , flow through which can be controlled by an adjustment knob 86 . structure is preferably provided to avoid excessive operation of the air compressor 52 . a gas pressure sensor switch 90 is adapted to sense gas pressure in the system , preferably in the tank 66 , and to open and switch off operation of the compressor 52 when the pressure has risen to a set point maximum . the switch 90 is adapted to close , and to actuate the compressor 52 , when the pressure has fallen to a set point minimum . these set points can vary depending on the particular dimensions and flow rates which are required , although a set point minimum of about 5 psig and a set point maximum of about 30 psig are presently preferred . a liquid level switch , here the float switch 94 , is provided in the reservoir 32 to prevent excessive cycling of the compressor 52 in the event that all of the liquid is discharged from the reservoir 32 . the float switch 94 includes a float 96 connected to an actuating arm 98 at a pivotal connection 100 . the arm 98 is adapted to make contact with a switch member 104 whenever the level of the liquid 34 in the reservoir 32 is above a minimum value . this closes the switch 94 to permit operation of the compressor 52 . the switch member 104 is biased against the arm 98 , and when the level of the liquid 34 falls below the set point minimum , the switch member 104 is extended to a position where the float switch 94 is opened and operation of the compressor 52 is prevented . this will prevent excessive cycling of the compressor 52 whenever the liquid 34 has been substantially discharged from the reservoir 32 . the control of the compressor 52 by the gas pressure sensor switch 90 and the float switch 94 is more easily understood with reference to the circuit diagram in fig5 . the compressor 52 , battery 62 , gas pressure sensor switch 90 , and float switch 94 can be conveniently provided in a simple series circuit . an open condition in either the gas pressure sensor switch 90 or the float switch 94 opens the series circuit and prevents operation of the compressor 52 . a simple manual switch , such as the switch 108 , can be provided to permit manual shutdown of the system . suitable components for the invention can be selected from several that are currently available . the air compressor can be a model 70 , manufactured by the marbuchi company , hong kong . a suitable air pressure sensor switch is the 20d10 manufactured by airlogic in racine , wis . a preferred pressure regulator is rsm - oo - loo manufactured by the wilkerson company of denver , colo . the battery is selected primarily to suit the requirements of the compressor motor , and a 6 - volt battery is presently preferred . the housing 20 can be formed from any suitable material , although high - density plastics are presently preferred for their strength and resistance to corrosion . the housing 20 can be provided in several alternative forms , although the semi - circular construction shown in the figures is preferred . this form permits a wrap - around engagement to the plant grow pot 18 , and can easily be molded into separate liquid reservoir and gas tank compartments . a compressor compartment 110 can also be formed in the housing 20 to contain the compressor 52 , motor 60 , battery 62 , pressure regulator 70 , and various conduits and wiring . a removable cover 114 can be provided to permit access to the compressor compartment 100 , especially to change the battery 62 . this invention can be embodied in several alternative forms without departing from the spirit or essential attributes thereof , and accordingly , reference should be made to the following claims , rather than to the foregoing specification , as indicating the scope of the invention .
plant irrigation apparatus is provided with a reservoir . water is placed inside the reservoir filling a portion of its volume . a pressurized gas is also introduced into the reservoir . the water is forced by the gas pressure out of the reservoir through at least one outlet conduit communicating with the water in the reservoir . water leaves the outlet conduits through at least one discharge outlet . the apparatus can include structure for hanging the apparatus from a plant grow pot . gas pressurization apparatus is utilized to provide a substantially constant supply of pressurized gas in the reservoir .