BACKGROUND

The present invention is directed to deep water culture hydroponic systems, and more particularly to nutrient solution circulation equipment and methods for such systems.

Deep water culture (DWC) hydroponic systems are widely used. Such systems generally include individual growing buckets interconnected by a common pipeline for (a) circulating nutrient solution to the buckets and (b) maintaining a common liquid level in the buckets. Various designs are used, depending on the number of buckets in the system.

The most commonly used designs are bottom systems, such as those manufactured by Current Culture H2O, especially under the UNDER CURRENT® trademark. These systems feature an “epicenter” or reservoir tank, which serves as the nutrient mixing tank and usually includes a float valve to maintain a pre-set liquid level. The epicenter tank feeds nutrient solution to one or more rows of growing buckets connected to the epicenter tank by the common pipeline, which is near the bottom of the tanks. At the end of each row, a pump is provided to draw nutrient solution from the pipeline and return it to the epicenter tank. This design creates a circulation in which nutrient flows from the epicenter tank, progresses from one tank to the next in a sequential or serial order, and then returns to the epicenter tank. This design often includes a system air pump and bubblers in each grow tank to oxygenate the nutrient solution.

Unfortunately, existing bottom systems have a number of shortcomings in their design and performance.

First, existing bottom systems generally require a large diameter (2.5″ or more) pipeline to enable nutrient solution circulation and to maintain a common nutrient solution level in the tanks by gravity. Accordingly, labor and material costs are relatively high. Installation and assembly require skill and precision to assure proper leak-free operation. Tanks become rigidly constrained to each other.

Second, existing bottom systems use progressive or sequential circulation, which leads to variation in nutrient solution quality delivered to each bucket. Circulation rate is limited in order to assure gravity equalized tank levels. As a result, plants are not consistently maintained in equal nutrient environments. This manifests itself in roots seeking nutrient and growing into the circulation piping between tanks, potentially partially blocking circulation of nutrient.

Third, in existing bottom systems, nutrient concentrations and pH level must be adjusted as plants grow. These adjustments are slow to make in bottom systems. Chemicals must be added slowly to the epicenter tank to avoid shocking the plants, particularly the plants in the first buckets downstream of the epicenter. This process reduces the time that system operators have for other tasks.

SUMMARY

The aforementioned problems are overcome by the present invention.

In a first embodiment of the invention, the DWC nutrient circulation system supplies the grow tanks in parallel and empties the grow tanks at essentially the same rate as the tanks are filled. Therefore, each grow tank receives the same volume and the same quality of nutrient solution, and the level of the solution across grow tanks is equal.

The hydroponic system of the first embodiment includes a plurality of grow tanks arranged in pairs, a circulation pump having an inlet and an outlet, a nutrient supply line fluidly connecting the outlet of the circulation pump to the grow tanks, and a tank drain line fluidly connected to the grow tanks. Each of the grow tanks is fluidly connected in parallel between the nutrient supply line and the tank drain line. The system further includes (a) a pump suction line fluidly connected to the inlet of the circulation pump and (b) a plurality of bridge connectors each fluidly connecting the tank drain line to the pump suction line.

This first embodiment of the DWC plumbing system provides a number of advantages over known systems. The DWC system maintains equalized tank solution levels across the grow tanks, and the system delivers fresh nutrient to the grow tanks essentially simultaneously in essentially equal volumes. The DWC system enables the use of relatively small diameter pipe, fewer and simpler tank connections, and a consistent method for scaling system size from two to virtually any number of tanks operating together. The DWC system eliminates the need for the series connection of grow tanks. The DWC system enables flexible grow tank configurations and connections, which simplify setup, operation, and maintenance, all using relatively low-skilled labor. The DWC system enables grow tanks to be individually moved or removed for cleaning.

In a second embodiment of the invention, the DWC system includes a nutrient supply tank fluidly connected to the circulating pump intake through a valve arrangement. This enables fresh nutrients and/or pH change chemicals to be added to the system through the nutrient supply tank. The contents of the nutrient supply tank are drawn into the pump suction line and are mixed with the recirculating solution from the grow tanks. The mixture or blend is pumped through the piping, and is injected into the grow tanks in a relatively short time, essentially simultaneously and in essentially equal amounts to each grow tank.

This second embodiment of the DWC plumbing system provides a number of advantages over known systems. For example, the DWC system enables the relatively simple, safe, and rapid adjustment of nutrient and pH levels of the nutrient solution, thereby reducing the risk of shocking the plants.

These and other advantages and features of the invention will be more fully understood and appreciated by reference to the description of the current embodiment and the drawings.

