CA1225832A

CA1225832A - Hydroponic unit

Info

Publication number: CA1225832A
Application number: CA000431164A
Authority: CA
Inventors: Bruce Duncan
Original assignee: Individual
Current assignee: Individual
Priority date: 1983-06-24
Filing date: 1983-06-24
Publication date: 1987-08-25

Abstract

ABSTRACT OF THE DISCLOSURE
A hydroponic apparatus includes a pair of containers, one of which is a growing container and the other of which is a second growing container or a liquid reservoir, and a U-tube interconnecting the bottoms of the containers. Liquid contain-ing nutrients is caused to oscillate between the containers by the injection of air under pressure into the horizontal arm of the U-tube.

Description

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This invention relates particularly but not exclusively to a hydroponic apparatus.
When growing plants hydroponically, liquid containing nutrients must be circulated in the growing container. There are a variety of devices intended to perform such ~unction.
Examples of such devices are described in United States Patents Nos. 2,983,076, issued to P.D. Merrill on May 9, 1961 and ~,016,677, issued to H. Julinot on April 12, 1977. Both of the ~atents describe somewhat complicated devices for supplying water to a growing chamber. The Merrill device includes a pump and valve structures which must be supplied with each unit.
The Julinot device utilizes air bubbles to supply nutrients to tha plants. The tube for supplying the air bubbles has a special design, and consequently would be somewhat expensive to manu-~actur~. Obviously, it would be advantageous to simplify thestructure for supplying water and nutrients to the plant growing container.
The object of the present invention is to provide a r~latively simple, pneumatically operated hydroponic apparatus.
Accordingly, the present invention relates to a hydro-ponic apparatus of the type including at least a first growing container ~or growing plants, a second plant gxowing or reservoir container, and a liquid inlet duct in each of said first and s~cond containers, said apparatus comprising subst~ntially U-~5 shaped tube means for interconnecting said inlet ducts; and a .

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gas inlet in said tube means for introducing gas under pressureinto said tube means, whereby a pressure differential is estab-lished in first one vertical arm and then in the other vertical arm of said tube means to cause the liquid to oscil]ate between 5 said containers.
The invention will now be described in greater detail with reference to the accompanying drawing, which illustrates a preferred embodiment of the invention, and wherein the single ~i~uxe is a schematic partly sectioned side elevation view of 1~ a growing apparatus in accordance with the present invention.
Referring to the drawing, the basic elements of the ~rowing apparatus are a pair of containers 1 and 2, and a sub-stantially U-shaped tube 3 extending between the containers 1 and 2. One of the containers 1 and 2 is a growing container, and the other container is a second growing container or a fluid reservoir. Of course, the growing container(s) is provided with the appropriate support for a plant or plants. The tube 3 in-cludes a pair of vertical arms 4 and 5, and a horizontal section interconnecting such vertical arms. An inlet 7 is provided in the hoxizontal section 6 of the tube 3 for introducing air under pressure into the tube. The tube 3 is formed of plastic, metal or ceramic, and need not be of uniform cross-sectional area or wall thickness. The vertical arms 4 and 5 of the tube 3 enter the containers 1 and 2 at the level of the lowest desired fluid level in the containers. The distance between the bottom of the ... ~ :. . ~
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containers 1 and 2 and the horizontal section 6 of the tube 3 is equal to or greater than the vertical distance between the lowest and highest liquid levels in the containers 1 and 2.
In operation, with liquid in the containers 1 and 2 and the tube 3, compressed air is injected through the inlet 7 into the hoxizontal section 6 of the tube 3. The compressed air ~>xoduces air bubbles which accumulate in the section 6 and then in the vertical arms 4 and 5. Ultimately, the gas to liquid ratio becomes higher in one of the arms g and 5, i.e. there is a pxessure differential across the vertical section 6 of the tube 3. The liquid in the arm 4 or 5 with the highest pressure head flows through the horizontal section 6 of the low pressure arm 4 or 5, carrying the gas bubbles being produced in the hor-i~ontal section 6.
The flow of liquid to the low pressure arm g or 5 con-tinues until the liquid level on the high pressure side of the tube is decreased to a level at which either the air is drawn in-to the top end of the arm 4 or 5, or the head pressure of the hi~h pressure arm becomes lower than the pressure in the low

2~ px~ssure arm 4 or 5. Then, the pressure differential across the horizontal section 6 of the tube 3 reverses, and the flow of liquid and gas bubbles is reversed initially to increase the pressure differential and then to maintain the differential to ensure a continuous liquid flow. Thus, the fluid in the tube 3 continuously oscillates between the two containers 1 and 2 until , ~,%5~33~

the injection of gas is stopped. Of course, liquid can be added to the system from time to time to replace liquid lost to the plants or by evaporation.
As will be appreciated, apparatus according to the present invention could also be utilized in any environment, ~or ex~mple in sewage treatment systems or in photographic processing, whexe it is advantageous to oscillate fluid between ~ne or more containers or tanks.

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Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE PROPERTY
OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. An apparatus of the type including at least a first container, a second container, and a liquid inlet duct in each of said first and second containers, said apparatus comprising substantially U-shaped tube means for interconnecting said inlet ducts; and a gas inlet in said tube means for introducing gas under pressure into said tube means, whereby a pressure differ-ential is established in first one vertical arm and then in the other vertical arm of said tube means to cause the liquid to oscillate between said containers.

2. A hydroponic apparatus of the type including at least a first growing container for growing plants, a second plant growing or reservoir container, and a liquid inlet duct in each of said first and second containers, said apparatus com-prising substantially U-shaped tube means for interconnecting said inlet ducts; and a gas inlet in said tube means for intro-ducing gas under pressure into said tube means, whereby a pressure differential is established in first one vertical arm and then in the other vertical arm of said tube means to cause the liquid to oscillate between said containers.

3. An apparatus according to claim 1, wherein said first and second containers are plant growing containers.

4. An apparatus according to claim 2, wherein said second container is a plant growing container.

5. An apparatus according to claims 1, 2 or 4, wherein said containers are normally at substantially the same level during use, and the distance between the bottoms of said contain-ers and the horizontal section of said tube means is at least equal to the vertical distance between the highest and lowest liquid levels in containers.