LARGE SCALE HYDROPONIC SYSTEM

The specification discloses a large scale hydroponic system including a plurality of grow tanks interconnected in a subsystem, and a reservoir. The reservoir is connected to the grow tanks through a pump that outputs nutrient fluid through a nutrient supply line. The nutrient supply line is connected to the grow tanks through a subsystem supply line. The subsystem supply line supplies fresh nutrient fluid to each of the grow tanks in the subsystem at substantially the same time. Excess nutrient fluid is exits the grow tanks through an overflow line, which is connected to the reservoir and returns the excess nutrient fluid to the reservoir. A drain line may be connected to the grow tanks to allow the nutrient fluid to be removed from the grow tanks. The drain line is connected to the reservoir and returns the removed nutrient fluid to the reservoir.

BACKGROUND OF THE INVENTION

The present invention relates to hydroponic systems, and more particularly to large scale hydroponic systems.

Recirculating deep water culture (RDWC) hydroponic systems are widely used. Many growers favor RDWC hydroponic systems because of their speed of plant growth and their size of harvest. In an RDWC system, plants are suspended in grow buckets of liquid nutrient with just their roots in contact with the nutrient. Grow buckets are interconnected by piping and a pump that continuously recirculates the liquid nutrient. RDWC hydroponic systems maintain the same liquid level in all grow buckets. Therefore, the number of buckets that may be serviced by a single pump is limited.

There are two known methods for providing equal liquid levels. The first, and most commonly used, method is a bottom system, such as that manufactured and sold by Current Culture H2O, especially under the UNDER CURRENT® trademark. These systems feature an “epicenter” or reservoir tank, which serves as the nutrient adjustment and 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. The rows of growing buckets are connected together in a chain via large diameter pipe segments. 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. Put another way, nutrient passes successively into and out of each bucket near the bottom. The pump draws the nutrient from the end bucket in the chain and pumps it back into the first bucket in the chain, so that there is a continuous recirculation of nutrient through the sequence of grow buckets. This design often includes a system air pump and bubblers in each grow tank to oxygenate the nutrient solution and thereby increase plant growth rate.

In this first method, the rate of flow of the nutrient solution is limited so that all the bucket levels may equalize through the pipe connection. The size of the pump may be determined by the rate of flow limitation, the size of the pipe feeding the chain of grow buckets, and the number of grow buckets. For example, a large system of this type may have four rows of grow buckets with each row of grow buckets containing no more than 12 grow buckets. The interconnecting pipes within each row are joined by headers at each end so that the grow buckets in each row may communicate and maintain the same liquid level. Flow circulates from the epicenter tank into the header feeding the first bucket in each row and progresses into each successive bucket in the row to the end bucket and then into the header from which the pump suction line draws the nutrient and pumps it back into the epicenter. This is a “closed” system, meaning the same nutrient is cycled continuously within the system.

This first method has several disadvantages.

First, these 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. And the tanks become rigidly constrained to each other.

Second, these 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 these systems, nutrient concentrations and pH level must be adjusted as plants grow. These adjustments are slow to make in these 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.

The second method, manufactured and sold by Hydra Unlimited under the HydraMax® trademark, features a circulation system in which nutrient is pumped into each grow bucket through circulators which aspirate air and inject oxygenated nutrient into the grow bucket. Each grow bucket receives the same flow rate of fresh aerated nutrient at the same time, rather than progressively, one bucket after the other as in the first method. The movement of flow out of each bucket is equalized and controlled by a pump and piping network designed to balance the amount of flow out of each bucket, maintaining an equal liquid level in the buckets. Like the first method, this is a closed system. This method does not utilize a separate air pump and mixes air and nutrient in a one to one ratio by volume for efficient oxygenation. Systems of this type may have up to 100 grow buckets.

Unfortunately, existing hydroponic systems may not be well suited to very large growing operations that may have thousands of plants. First, the systems of the types described above divide the plants into relatively small, closed groups, which may not be desirable for large scale growing operations. Each closed system requires its own pump and its own nutrients; and a large number of closed systems requires more oversight, nutrient monitoring instrumentation, and labor than desired.

Commercial growing operations tend to use a centralized nutrient system that is typically delivered to the plants in drip systems with the plants growing in rock wool or other inert grow media. These systems have reduced nutrient management costs. RDWC systems have superior plant growth when compared to drip systems, but the cost of known RDWC systems for large scale operations has been undesirably high. While the growth of individual plants is superior in deep water culture compared to drip systems, the cost is undesirably high in operations of this scope.

SUMMARY OF THE INVENTION

In a first aspect of the present invention, a large scale hydroponic system may include a plurality of grow tanks and a nutrient reservoir. Each of the plurality of grow tanks may include an overflow outlet and a drain outlet. A nutrient supply system may interconnect the nutrient reservoir to each of the plurality of grow tanks in parallel. A nutrient overflow system may interconnect the overflow outlet of each of the grow tanks in parallel with the reservoir. A drain return system may interconnect the drain outlet of each of the grow tanks in parallel with the reservoir.

In a second aspect of the present invention, a large scale hydroponic system may include a plurality of grow tanks and a reservoir containing nutrient fluid. Each grow tank may include a circulator. The grow tanks may be arranged in subsystems of grow tanks that are connected together. A circulation pump may be connected to the reservoir at its inlet and to a nutrient supply line at its outlet. The nutrient supply line may be connected to at least one subsystem supply line. The subsystem supply line may be connected to a plurality of circulator supply lines, which each may be connected to the circulator of one of the grow tanks. Pressurized nutrient fluid may flow from the circulation pump through the nutrient supply line, into the subsystem supply line, and to the circulator supply lines. The circulator may aerate the nutrient fluid and inject the aerated nutrient fluid into the grow tank. The nutrient fluid may be provided to each of the grow tanks in the subsystem at substantially the same time.

An overflow line may be fluidly connected to the reservoir and to at least one subsystem overflow line. Tank overflow lines may connect each grow tank in a subsystem to the subsystem overflow line. Nutrient fluid may flow out of the grow tanks through the tank overflow lines, the subsystem overflow line, and the overflow line into the reservoir.

In a first refinement of the present invention, a drain line may be fluidly connected to the reservoir. A plurality of tank drain lines may connect each of the grow tanks to a subsystem drain line, which in turn may be connected to the drain line. A plurality of valves may be connected between the grow tank and the subsystem drain line. When the valve is in an open position, the nutrient fluid may drain from the corresponding grow tank and into the reservoir. In one aspect, each of the plurality of valves is normally in a closed position.

In a second refinement of the present invention, a subsystem drain line may be fluidly connected to the reservoir. A plurality of tank drain lines may each connect one of the grow tanks to the subsystem drain line. A valve between the subsystem drain line and the reservoir may regulate the flow of nutrient fluid between the subsystem drain line and the reservoir. When the valve is in an open position, the nutrient fluid may drain from each of the grow tanks in the subsystem.

In a third aspect of the present invention, the subsystem overflow lines may be fluidly connected to an overflow receptacle. An overflow pump may be connected to the overflow receptacle at the overflow pump's inlet and to an overflow line at the pump's outlet. The overflow pump may transfer the nutrient fluid from the overflow receptacle through the overflow line to the reservoir.

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

DESCRIPTION OF THE CURRENT ASPECTS

Various aspects of a large scale hydroponic system including a reservoir and subsystems of grow buckets are shown and described herein.

A large scale RDWC hydroponic system is shown and described. In one aspect, the system may include a network of circulators for each grow bucket. The grow buckets may alternately be referred to as grow tanks. The circulators may aerate and inject fresh nutrient substantially simultaneously into each grow bucket. At the same time, the system may drain an equal amount of nutrient from each grow bucket and returns it to the central reservoir. The system may be described as an “open” system because it includes a centrally maintained nutrient, common to all grow buckets, independent of the number of grow buckets in the system. The system may reduce nutrient management costs, simplify plumbing, and uniformly nourish all plants. Individual rows of plants may be excluded or included in the recirculating circuit. This gives an operator the ability to operate the facility at full or partial capacity. It also may give the operator the ability to easily place additional grow buckets into service without interrupting the operation of existing grow buckets. The system allows RDWC to be functional and practical for large scale hydroponic agriculture.

In one aspect, a large scale hydroponic system may include a plurality of grow tanks and a nutrient reservoir. Each of the plurality of grow tanks may include an overflow outlet and a drain outlet. A nutrient supply system may interconnect the nutrient reservoir to each of the plurality of grow tanks in parallel. A nutrient overflow system may interconnect the overflow outlet of each of the grow tanks in parallel with the reservoir. A drain return system may interconnect the drain outlet of each of the grow tanks in parallel with the reservoir.

All of the connections described herein allow for fluid communication.

InFIG.1, a large scale hydroponic system100according to one aspect is shown. The hydroponic system100may include a plurality of grow tanks110. The grow tanks110may alternately be referred to as grow buckets. Each grow tank110may contain one plant. The grow tanks110may be arranged in rows and the grow tanks110in each row may be interconnected through a system of pipes as shown and described in more detail with reference toFIG.2. In one aspect, connecting the grow tanks110in rows as needed may create groups of plants that mature at progressive intervals to provide continuous harvesting. Put another way, planting the plants one row at a time may allow each row of plants to mature at a different time from the other rows to provide continuous harvesting. Each row of grow tanks110may be referred to as a subsystem, for example, subsystem112.

As shown inFIG.1, the system100may include a grow table102on which the grow tanks110and their associated plumbing may be placed and/or arranged. In one aspect, more than one grow table102may be connected in series to create larger subsystems112. The liquid level in each grow tank110in the subsystem112may be maintained at substantially the same level as all of the other grow tanks110in the subsystem112. In one aspect, the liquid level in each of the grow tanks110in the subsystem112may be within half an inch of the liquid level in the other grow tanks110in the subsystem112. The system100may include a reservoir120. The reservoir120may provide a central location where nutrient concentrations may be monitored and controlled. The reservoir120may contain an amount of a nutrient fluid. The reservoir120may have a different level of nutrient fluid than the level of nutrient fluid in the grow tanks110. In one aspect, a nutrient supply170may be connected to the reservoir120. The nutrient supply170may be continuously or periodically added to the reservoir120either manually or automatically. A circulation pump130may be connected to the reservoir120at its inlet. The outlet of the circulation pump130may be connected to a nutrient supply line140. In one aspect, a circulator valve (not shown) may be at the outlet of the circulation pump130. When the circulator valve is in a closed position, the circulator valve may prevent the flow of nutrient fluid between the reservoir120and the grow tanks110. In one aspect, the circulator valve in the closed position may prevent the flow of nutrient fluid between the reservoir120and the nutrient supply line140even if the level of nutrient fluid in the reservoir120and in the grow tanks110are different. When the circulator valve is in an open position, nutrient fluid may flow from the reservoir120to the nutrient supply line140through the circulation pump130.

A plurality of subsystem supply lines142may branch off of the nutrient supply line140to carry the nutrient fluid to the grow tanks110. The subsystem supply lines142may alternately be referred to as subsystem nutrient supply lines or circulator supply lines. The subsystem supply line142may supply fresh nutrient to each grow tank110in its subsystem. The nutrient fluid that flows through the nutrient supply line140may be pressurized. In one aspect, the subsystem supply lines142and the nutrient supply line140may form one integral component.

In one aspect, a subsystem supply line542and a nutrient supply line540may be connected through a subsystem nutrient supply valve502as shown inFIG.5. When the subsystem nutrient supply valve502is in the open position, nutrient fluid may flow from the nutrient supply line540to the subsystem supply line542. When the subsystem nutrient supply valve502is in the closed position, nutrient fluid may be prevented from entering the subsystem supply line542from the nutrient supply line540. In one aspect, the subsystem nutrient supply valve502may be in the normally open position. In one aspect, the subsystem nutrient supply valve502may be used to adjust the pressure of the nutrient fluid flowing to the grow tanks110.

FIG.2shows a single grow bucket110and its plumbing according to one aspect. In one aspect, the grow tanks110may have at least one leg214extending from a bottom surface of the grow tank110that defines a space below the grow tank110to allow the plumbing to run underneath the grow tank110. The subsystem supply line142may be connected to a plurality of circulator supply lines144. There may be one circulator supply line144for each grow bucket110. As shown inFIG.2, each circulator supply line144may be connected to a circulator210. The circulator210may aerate the nutrient fluid and inject the aerated nutrient fluid into the grow tank110. As shown inFIG.2, the circulator210may aerate the nutrient fluid by way of a snorkel212. The circulator210may be mounted to a wall of the grow tank110. As shown inFIG.2, the circulator210may be mounted in a corner of the grow tank110. As shown inFIG.2, in one aspect, the circulator210may be configured to inject the aerated nutrient fluid near the bottom of the grow tank110. In an alternate aspect, the circulator210may inject the aerated nutrient fluid at any other suitable location of the grow tank110. In an alternate aspect, the circulator supply line144may be directly connected to the grow tank110.

In one aspect, each of the circulator supply lines144may be connected to the subsystem supply line142through a circulator supply valve. The circulator supply valve may restrict the flow of nutrient fluid from the subsystem supply line142to the circulator supply lines144. Put another way, the circulator supply valve may restrict the flow of nutrient fluid to the grow tank110. When in the open position, the circulator supply valve may permit the flow of nutrient fluid from the subsystem supply line142to the circulator supply line144. When in the closed position, the circulator supply valve may restrict the flow of nutrient fluid from the subsystem supply line142to the circulator supply line144. In one aspect, the circulator supply valves may be in the normally open position.

Returning toFIG.1, an overflow line150may be connected to the reservoir120. A subsystem overflow line152may branch off of the overflow line. The subsystem overflow line152may carry the excess nutrient fluid removed from each grow tank110to the overflow line150where it is returned to the reservoir120. The size of the subsystem overflow line152may vary in size depending on the number of grow tanks110in the subsystem112. For example, a two inch subsystem overflow line152may be used with a subsystem112containing 30 grow tanks110. In one aspect, placing the grow tanks110on the grow table102elevates the grow tanks110with respect to the reservoir120, which may allow for easier flow of the nutrient fluid in the overflow line150and a drain line160(described in more detail below) due to the force of gravity. In one aspect, as shown inFIG.5, the overflow line may be angled with respect to the ground plane to ease movement of the nutrient fluid from the grow tanks110to the reservoir120.

As shown inFIG.2, a tank overflow line220may be connected to the subsystem overflow line152. The overflow assembly may be mounted to the sidewall of the grow tank110at the desired liquid level. The tank overflow line220may be in fluid communication with the nutrient fluid in the grow tank110through a port222in one side of the grow tank110. In one aspect, as the nutrient fluid flows into the grow tank110an equal amount of nutrient fluid may be removed from the grow tank110through the tank overflow line220and returned to the reservoir120. In one aspect, the amount of nutrient fluid removed from the grow tank110may depend on the level of nutrient fluid already present in the grow tank110. For example, if the amount of nutrient fluid added to the grow tank110and the amount of fluid already present in the grow tank110when combined does not rise to the height of the port222, no nutrient fluid will be removed from the grow tank110.

As shown inFIG.1, the hydroponic system100may include a drain line160. The drain line160may be fluidly connected to one or more subsystem drain lines162and the reservoir120. In one aspect, the subsystem drain line162may assist in keeping a uniform flow rate across all of the circulators210in a subsystem112. In one aspect, the subsystem drain line162may help to keep a substantially uniform nutrient fluid level in each of the grow tanks110in the subsystem112. In one aspect, the subsystem drain line162may help to keep uniform aeration across all the grow tanks110in the subsystem112. In one aspect, the subsystem drain line162may assist in creating a uniform recirculation rate to all grow tanks in the subsystem112. In one aspect, the nutrient fluid may move through the drain line160using the force of gravity. The subsystem drain line162may be connected to at least one tank drain lines362for each grow tank110as seen inFIG.3. As shown inFIG.2, the tank drain line362may be in fluid communication with its corresponding grow tank110through a drain port230. Each drain port230may contain or be in connection with a valve. When the valve is open, the nutrient fluid may flow out of the grow tank110and into the subsystem drain line162and drain line160. When the valve is closed, the nutrient fluid may only leave the grow tank110through the subsystem overflow line152. In one aspect, the valves may be in a normally closed position. The drain line160may allow the fluid to be drained from each of the grow tanks110individually or as a subsystem. This allows individual grow tanks110or subsystems of grow tanks112to be added to or removed from the hydroponic system100as needed without impacting the other grow tanks110or subsystems in the system100. In one aspect, the fluid may be drained from the grow tanks110to facilitate cleaning the grow tanks110between growing cycles. In one aspect, the subsystem drain line162may allow a more powerful circulator210with a higher flow rate to be used in the system by draining more nutrient fluid from each of the grow tanks than may be removed by the subsystem overflow line152.

In one aspect, a drain line valve may be installed between each subsystem drain line162and the drain line160. When the drain line valve is in the closed position, the nutrient fluid may be maintained in the grow tanks110through the subsystem supply lines142and subsystem overflow lines152. When the drain line valve is in the open position, the nutrient fluid in all of the grow tanks110in the subsystem112may leave the grow tanks110and return to the reservoir120through the drain line160. In one aspect, the drain line valve may be in a normally closed position.

FIG.6shows a portion of a large scale hydroponic system according to one aspect. As shown inFIG.6, in one aspect, the subsystem drain lines162may connect to a grow table drain line164. The grow table drain line164may be connected to the drain line160. A drain line shut-off valve166may be installed between the grow table drain line164and the drain line160. When the drain line shut-off valve166is closed, it may prevent nutrient fluid from exiting the grow tanks110. When the drain line shut-off valve166is open, it may allow the nutrient fluid to exit the grow tanks110and return to the reservoir120. In one aspect, the drain line shut-off valve166may normally be in the closed position.FIG.7shows a back view ofFIG.6. InFIG.7, the drain line160is shown running underneath the grow table102. In one aspect, the drain line160may be sloped to facilitate flow of the nutrient fluid to the reservoir120. The drain line160is preferably located at the opposite end of the grow table102from the nutrient supply line140and the overflow line150. As shown inFIG.6, the subsystem supply lines142and the subsystem overflow lines152are closed at the end of the grow table with the drain line160. This may prevent the drain line160from crossing over any other pipe lines.

In one aspect, all or a portion of the plumbing of the grow tank110is designed to be modular. The grow tank110may be attached to a portion of the subsystem supply line142and the subsystem overflow line152. These portions may be attached to the subsystem supply line142and the subsystem overflow line152of another grow tank110to form a subsystem. The grow tank110may be connected to the drain line160through a port in the bottom of the grow tank110. The drain line160may also be modular.

In one aspect, there may be more than one subsystem of grow tanks110in the hydroponic system100. As shown inFIG.1, there are three subsystems of grow tanks110. Each subsystem may have its own plumbing as described above with reference to the subsystem112. Each subsystem may receive nutrient fluid from the supply line140, move nutrient fluid to the overflow line150, and drain nutrient fluid to the drain line independently from all other subsystems. As shown inFIG.1, the grow tanks110in each subsystem are arranged in a straight line on the grow table102. In an alternate aspect, the grow tanks110in each subsystem may be arranged in any suitable orientation.

InFIG.8, a front view of a hydroponic system800according to one aspect is shown. The hydroponic system800may have a plurality of grow tanks810. Each grow tank810may be connected to a subsystem supply line842which, in turn, may be connected to a nutrient supply line840. Each grow tank810may be connected to a subsystem overflow line852. As shown inFIG.8, the subsystem drain line862may terminate in an open end over an overflow receptacle854. The overflow receptacle may collect the overflow from one or more subsystems. In one aspect, the subsystem drain line82may be coupled to the overflow receptacle854. In one aspect, the subsystem drain lines82may join to a receptacle drain line (not shown) that may output the nutrient fluid into the overflow receptacle854. An overflow pump856may have an outlet and an inlet. The inlet of the overflow pump856may be connected to the overflow receptacle854. The outlet of the overflow pump856may be connected to the overflow line850. When the overflow pump856is running, the overflow pump856may transfer the nutrient fluid from the overflow receptacle854to the reservoir (not shown) through the overflow line850. If the number of grow tanks in the system is increased to the point where the inflow is above the design limit of the overflow pump856, the size of the overflow pump856may be increased.

As shown inFIG.8, there may optionally be a level switch858in the overflow receptacle854. The level switch858may start in a position that blocks the inlet of the overflow pump856. As nutrient fluid enters the overflow receptacle854, it may lift the level switch858toward the top of the overflow receptacle854. When a sufficient amount of nutrient fluid enters the overflow receptacle854(put another way, the nutrient fluid reaches a preset point), the level switch858may be raised enough that it does not obstruct the inlet of the overflow pump856and the overflow pump856may turn on. As the overflow pump856removes the nutrient fluid from the overflow receptacle854, the level switch858may be lowered until it covers the inlet of the overflow pump856. When the level switch858covers the inlet of the overflow pump856, the overflow pump856may turn off. In one aspect, the overflow pump856may be sized to maintain a flow rate equal to or greater than the inflow rate from the subsystem overflow lines852. In one aspect, the size of the overflow pump856may be selected based on the inflow rate from the subsystem overflow lines852and the pressure drop in the overflow line850returning the nutrient fluid to the reservoir.

An exemplary large scale hydroponic system is now described. The flow rate of nutrient fluid both into and out of each grow tank110may be of 0.7 gallons per minute (“GPM”) or 42 gallons per hour (“GPH”). The nutrient fluid may be supplied through the nutrient supply line140at a supply pressure of 5 pounds per square inch (“PSI”). At that supply pressure, each circulator may consume 0.002 horsepower. For a large scale hydroponic system with 2500 grow tanks, the total power consumption by the circulators may be 5 horsepower. The exemplary large scale hydroponic system may be supplied by one or more large capacity pumps. If one large pump is used, its output may be connected to a manifold and nutrient supply lines may be routed from the manifold to individual grow tables. If multiple pumps are used, pump inlets may be independently connected to the reservoir and their outputs may be connected to individual grow tables without the need to feed a common output manifold. This may maximize the performance of each pump and eliminate the potential problems of balancing multiple pumps feeding the same manifold.

In one aspect, the grow tables may each support multiple rows (subsystems) with 15 or 16 buckets each. If the exemplary system utilizes an overflow receptacle, the total circulation rate for a 2500 grow tank system may be 1750 GPM. In one aspect, the system may utilize more than one overflow receptacle and more than one overflow pump to reduce pipeline pressure drops. This may reduce the size of overflow pump required.