with reference to fig1 , the apparatus includes a water pipe adaptor 100 that can be glued , threaded , or otherwise connected in series with a water pipe in an irrigation system . a treatment liquid input port 102 extends at least partly upward from the water pipe adaptor , and an exchangeable treatment liquid container 104 can be attached to the treatment liquid input port 102 by a water tight connection 106 , thereby supporting the treatment liquid container in an at least partly inverted orientation so that treatment liquid 108 contained in the treatment liquid container 104 drains toward the water pipe adaptor 100 . in the embodiment of fig1 , water flowing through the water pipe adaptor past the treatment liquid input port creates a low pressure suction according to the venturi effect , thereby enhancing the tendency for liquid from the treatment liquid container to flow into the irrigation system . fig2 illustrates a preferred embodiment of the present invention wherein a section of a pvc water pipe has been removed and the ends of the remaining pipe have been inserted and glued into the ends 200 of the water pipe adaptor 100 . the connection 106 between the treatment liquid input port 102 and the treatment liquid container 104 includes a female threaded section in the treatment liquid input port that is compatible with a male threaded section at the outlet of the treatment liquid container 104 . a washer 202 , similar to a standard garden hose washer , provides a water tight seal between the treatment liquid container 104 and the treatment liquid input port 102 . a disk - shaped barrier 204 partially blocks the flow of liquid into the treatment liquid input port . treatment liquid flows into the treatment liquid input port 102 through a hole in the barrier 204 that is located near the center , where the venturi effect suction is strongest . the hole is sized so as to allow the contents of the treatment liquid to flow from the treatment liquid container into the irrigation system at a desired rate , which in some preferred embodiments causes the entire contents of the treatment liquid container to enter the irrigation system in approximately 10 minutes . one or more additional holes are located near the perimeter of the barrier 204 , where the venturi effect is weaker , so as to allow water and / or air flowing through the irrigation system to enter the treatment liquid container and displace the treatment liquid . the embodiment shown in fig2 includes structural reinforcement 206 that enhances the ability of the treatment liquid input port to support the weight of a treatment liquid container . fig3 a illustrates a preferred embodiment that is similar to the embodiment of fig2 , except that the connection 300 between the treatment liquid input port and the treatment liquid container includes a male threaded section on the treatment liquid input port that is compatible with a female threaded section on the outlet of the treatment liquid container . fig3 b illustrates the same embodiment as fig3 a , in a configuration where the treatment liquid container has been removed and a replacement cap 302 is positioned to be attached to the treatment liquid input port in its place , so as to provide a water tight seal . fig3 c illustrates the embodiment of fig3 b with the replacement cap installed . as mentioned with regard to fig2 , some preferred embodiments include a barrier 204 that partially blocks the flow of liquid into the treatment liquid input port . a hole near the center of the barrier allows treatment liquid to flow into the irrigation system at a desired rate . with reference to fig4 a , in some of these preferred embodiments the barrier 400 includes a protrusion 402 that is shaped and sized so as to break a membrane that seals the outlet of a pre - filled treatment liquid container . in various embodiments , the membrane is made from coated paper , rubber , plastic , or a similar material , and can include scoring to facilitate penetration by the protrusion 402 . in fig4 a , a hole 404 in the center of the protrusion 402 allows liquid from the treatment liquid container to flow into the treatment liquid input port at a desired rate . additional holes 406 located near the perimeter of the barrier 400 , where there is less venturi effect suction , allow water and / or air flowing through the irrigation system to enter the treatment liquid container and displace the volume vacated by treatment liquid flowing into the irrigation system . fig4 b shows the barrier 400 of fig4 a installed in the connecting section 106 of a treatment liquid input port . some preferred embodiments do not include the additional holes 406 shown in fig4 a , but instead provide a treatment liquid container that is collapsible . in still other preferred embodiments , the treatment liquid is held within a collapsible bag or membrane located inside of a ventilated bottle or other supporting container . fig4 c illustrates a preferred embodiment in which treatment liquid 108 is contained within a collapsible bag 408 that is physically supported by a rigid or semi - rigid container 104 that includes ventilation holes 410 so as to allow air to fill the container 104 as the treatment liquid 108 enters the irrigation system and the bag 408 collapses . fig5 a illustrates a preferred embodiment similar to the embodiment of fig2 , except that the structural reinforcement 206 is larger and surrounds the lower portion of the treatment liquid container 104 . in addition , the water pipe adaptor 100 includes a constricted section 500 with a reduced inner diameter that causes water to flow more rapidly and thereby further increases the venturi effect suction . fig5 b shows the same embodiment from the front . fig5 c illustrates a replacement cap 502 that is compatible with the embodiment of fig5 a and fig5 b . the replacement cap 502 includes a connecting section 504 with male threads that is compatible with the connecting threads 106 of the treatment liquid input port 102 . the sides of the replacement cap 502 approximate the sides of the treatment liquid container near its threaded outlet , and the top of the cap includes a handle 506 to facilitate grasping the replacement cap and rotating it so as to engage and disengage it with the treatment liquid input port . fig5 d shows a top view of the replacement cap of fig5 c . fig5 e illustrates the embodiment of fig5 a and fig5 b , with the replacement cap of fig5 c and fig5 d installed . fig6 a illustrates the embodiment of fig1 attached to an in - ground sprinkler system . the sprinkler system includes a plurality of controlling check valves 600 that supply water to a series of pipes 602 delivering water to sprinkler heads 604 throughout the area to be irrigated , thereby delivering a shower of water 606 from each sprinkler head that approximates the effects of natural rainfall . the pipes 602 are located below grade 608 , so as to minimize the visibility of the irrigation system and also reduce tripping and other hazards . the water pipe adaptor 100 of the present invention is connected above grade in series with a water pipe that flows from a check valve 600 vertically downward to a below grade pipe 602 , and is oriented so as to support an exchangeable treatment liquid container inverted at an angle of approximately 45 degrees . fig6 b illustrates the embodiment of fig6 a attached to a horizontal section of water pipe of a similar sprinkler system . in this sprinkler system , the check valves 610 are separate from the control valves ( not shown ). fig6 c illustrates a preferred embodiment that is able to support treatment liquid containers that are too heavy to be supported by a treatment liquid input port , even with structural reinforcements . in this embodiment , the treatment liquid container is supported by a stand 612 resting on legs 614 that extend to the ground 608 . the treatment liquid input port 102 extends vertically at right angles to the water pipe adaptor 100 , which is connected in series to a horizontal section of pipe located below grade . fig7 a illustrates a preferred embodiment that includes a chamber 700 for housing one or more instances of the present invention and protecting them from exposure to the weather . in the embodiment of fig7 a , the chamber is located below grade 608 , except for the uppermost part and the covering lid 702 . in similar embodiments , it is located either above grade or only partly below grade . the chamber 700 includes one or more docking modules 704 , each of which rests on the bottom of the chamber and is able to support the weight of a treatment liquid container 706 , 708 and each of which includes a connecting section similar to the connecting section of fig2 or fig3 b ( not shown in fig7 a ), connectable to the outlet of a treatment liquid container 706 , 708 . in this embodiment , vent holes 712 , 714 are included in the bottoms of the treatment liquid containers ( i . e . near the parts of the containers that are uppermost when the containers are inverted and in use ) that allow air to enter the containers and displace the treatment liquid as it enters the irrigation system . venturi effect suction ensures that a negative pressure is applied to the treatment liquid container when the irrigation water is flowing , and gravity ensures that no treatment liquid escapes through the vent holes when the irrigation water is not flowing . in the embodiment of fig7 a , the vent holes 712 , 714 are sealed until use by sealing flaps glued over the vent holes . the flaps can be easily removed by pulling on one end of each flap that is left unglued and thereby easily graspable . in fig7 a , the flaps are shown partly removed 712 on two of the treatment liquid containers 706 , and not yet removed 714 on the third treatment liquid container 708 . similar vent holes and sealing flaps are used in other preferred embodiments over the full range of treatment liquid container sizes . in fig7 a , one of the treatment liquid containers 708 is shown positioned in preparation for connecting to its docking module 702 , so as to more fully show the shape of the treatment liquid container and the threaded connecting section 710 at its outlet . fig7 b is a top view of the embodiment of fig7 a , where the covering lid 702 has been omitted for visual clarity . the connecting sections 716 of the treatment liquid input ports can be seen in the central parts of the docking modules 704 . when a treatment liquid container 708 is not installed , a replacement cap similar to the cap shown in fig3 b 302 is used to seal the connecting section 716 of a treatment liquid input port . fig8 a is a side view of a preferred embodiment that uses a pressure differential rather than venturi effect suction to extract treatment liquid from the treatment liquid container . the pressure differential causes water to flow naturally into the treatment liquid container 104 and displace the treatment liquid . therefore , unlike embodiments that rely on venturi effect suction , there is no need for the treatment liquid container 104 to be collapsible , and there is no need for vent holes 406 such as the ones illustrated in fig4 a and fig4 b . the pressure differential in fig8 a is created by a constriction 500 that creates a region of higher water pressure 800 immediately upstream of the constriction 500 , and a region 802 of lower water pressure immediately below the constriction 500 . a water inlet tube 804 is connected between the region of higher pressure 800 and the treatment liquid container 104 , and a treatment liquid outlet tube 806 is connected between the treatment liquid container 104 and the region of lower pressure 802 . when water flows past the constriction 500 , the pressure differential causes some of the water to by - pass the constriction 500 and flow instead through the treatment liquid container 104 , thereby introducing liquid treatment 108 into the water flow . in the embodiment of fig8 a , the constriction 500 is tapered , so as to allow the flow of water to remain as laminar as possible . fig8 b illustrates an embodiment similar to the embodiment of fig8 a , except that it includes a water diverter 807 that intercepts some of the water flowing through the high pressure region 800 of the water pipe adaptor 100 and diverts it into the water inlet channel 804 . in this embodiment , the pressure differential caused by the constriction 500 and the physical interception of the water provided by the water interceptor 807 both serve as mechanisms that cause water to flow into the treatment liquid container 104 . the result is that more water flows into the treatment liquid container due to the combination of both mechanisms than would flow due to either mechanism alone . fig8 c presents a top view of the tapered constriction 500 , the water diverter 807 , and the distal end of the water inlet tube 804 from the embodiment of fig8 b . fig8 d illustrates the flow of water through the embodiment of fig8 b . as water flows through the restriction 500 , some of the water by - passes the restriction 500 and flows instead from the high water pressure area 800 upstream of the constriction 500 into the water diverter 807 , through the water inlet tube 804 , and into the treatment liquid container 104 . there the water mixes 808 with the treatment liquid 108 and increases the liquid pressure inside of the treatment liquid container 104 . this causes a mixture of water and treatment liquid to leave the treatment liquid container 104 through the treatment liquid outlet tube 808 and flow into the lower pressure area 802 of the water pipe adaptor 100 downstream of the constriction 500 . the process continues until the treatment liquid container 104 is fully diluted with water , and all of the treatment liquid 108 has been extracted from the treatment liquid container 104 . in some embodiments , the treatment liquid container 104 is transparent and the treatment liquid 108 is colored and / or at least partly opaque . in these embodiments , the color of the liquid in the treatment liquid container 104 can be seen to gradually turn clear as the treatment liquid 108 is diluted until none is left in the treatment liquid container 104 . the treatment liquid container 104 can then be removed and discarded , and a replacement cap 502 can be installed in its place . fig8 e illustrates the flow of water in a preferred embodiment similar to the embodiment of fig8 b , except that the treatment liquid 108 is contained in a flexible bag 408 , such that water entering the treatment liquid container 104 through the water inlet tube 804 is not mixed with the treatment liquid 108 , but instead fills the space 810 between the flexible bag 408 and the treatment liquid container 104 , thereby applying pressure to the flexible bag 408 and forcing treatment liquid 108 through the treatment liquid outlet tube 806 and into the lower pressure area 802 of the water pipe adaptor 100 downstream of the constriction 500 . the process continues until all of the treatment liquid has been extracted from the treatment liquid container 104 , at which point the empty flexible bag 408 seals the treatment liquid exit tube 806 and stops the flow of water through the treatment liquid container 104 . fig8 f is a side view of an embodiment with the treatment liquid container 104 removed . the embodiment is similar to the embodiment of fig8 b , except that the distal ends of the water inlet tube 804 and the treatment liquid outlet tube 806 both terminate in adjacent hollow points 812 that protrude into the treatment liquid input port 102 and are able to penetrate a membrane 814 that seals the treatment liquid container 104 . this allows the treatment liquid container 104 to be conveniently installed without a user coming into contact with the treatment liquid 108 . in various embodiments , the membrane 814 is made from coated paper , rubber , plastic , or a similar material , and can include scoring to facilitate penetration by the protruding hollow points 812 . a washer 816 similar to a common garden hose washer forms a water - tight seal between the treatment liquid container 104 and the treatment liquid input port 102 . fig8 g is a side view of the embodiment of fig8 f configured with a cap 502 installed in the treatment liquid port 102 so as to seal the treatment liquid input port 102 when not in use . the threaded area 504 of the cap 502 is hollow , so as to make space for the adjacent hollow points 812 at the distal ends of the water inlet tube 804 and the treatment liquid outlet tube 806 that protrude into the treatment liquid input port 102 . fig8 h is a side view of a preferred embodiment similar to the embodiment of fig6 c that uses an annulus as a constriction 500 , so as to create a pressure differential using only a short length of the water pipe adaptor 100 . in this embodiment , the water pipe adaptor 100 is buried below grade 608 , and the treatment liquid input port 102 extends vertically above grade 608 from the water pipe adaptor 100 . the exchangeable treatment liquid container 104 is supported by a stand 612 resting on legs 614 on the ground 608 . in the embodiment illustrated in fig8 h , water flowing through the inlet tube 804 mixes with treatment liquid 108 in the treatment liquid container 106 . in similar embodiments , as discussed in reference to fig8 e above , the treatment liquid 108 is contained in a flexible bag 408 and is forced into the water pipe adaptor 100 by water filling the space between the flexible bag 408 and the treatment liquid container 104 . fig9 a illustrates a preferred embodiment similar to the embodiment of fig7 a , but including a constriction ( not shown ) in each water pipe adaptor . in a similar manner to the embodiment of fig8 b , in this embodiment adjacent hollow , pointed distal ends 812 of water inlet channels 804 and treatment liquid outlet channels 806 protrude into the treatment liquid input ports 704 so as to penetrate breakable membranes that seal the ends of the treatment liquid containers 706 , 708 as the treatment liquid containers 706 , 708 are attached to the treatment liquid input ports 704 . unlike the embodiment of fig7 a , in this embodiment water flows into the treatment liquid containers 706 , 708 as the treatment liquid 108 is extracted . hence , there is no need for the air vents ( 712 , 714 in fig7 a ) that are included in the embodiment of fig7 a . fig9 b presents a top view of the embodiment of fig9 a with all of the treatment liquid containers 706 , 708 removed . other modifications and implementations will occur to those skilled in the art without departing from the spirit and the scope of the invention as claimed . accordingly , the above description is not intended to limit the invention except as indicated in the following claims .
an apparatus and method are disclosed for applying fertilizer , weed killer , pesticides , and other botanical treatment liquids through an in - ground irrigation system using an inexpensive , easily installed apparatus with exchangeable treatment containers . an adaptor connects in series with an irrigation pipe and supports an inverted treatment container . treatment liquid enters the irrigation system due to gravity , venturi effect suction , a pressure differential caused by a constriction in the adaptor , and / or a diverter that diverts water into the container . embodiments include a cap for sealing the adaptor , a barrier with a hole that controls treatment dispensing rate , a constriction for increased venturi suction , and / or a protrusion that penetrates a membrane seal on a pre - filled container . treatment liquid can be dispensed from a collapsible bag inside the treatment container . embodiments with large containers include structural reinforcements or separate supporting stands . some embodiments include a closable chamber that protects the apparatus from weather .