1. Field of the Invention
This invention relates to the field of filtration equipment for Marine Aquariums. More specifically, the invention comprises of a biopellet reactor intended to remove or reduce nitrates and phosphates from marine aquarium water.
2. Description of the Related Art
There currently several biopellet reactor designs available. The primary function of a biopellet reactor is mix tank water with bio-degradable plastic pellets. Naturally occurring bacteria in the aquarium water utilize the biodegradable plastic pellets as a carbon source for metabolism allowing them to grow and multiply on the surface of the pellets. In addition to utilizing the pellets as a carbon source, the bacteria also draw phosphate and nitrate from the aquarium water as sources of phosphorus and nitrogen which are necessary for cell growth and replication. Nitrate and phosphate are also used by algae and other nuisance aquarium inhabitants so biopellet reactors have been shown to improve overall aquarium water quality and reduce the growth of nuisance organisms.
A standard biopellet reactor provides several functions in an aquarium filtration system. First, it provides a retaining system that allows tank water to pass through the pellets without allowing the pellets to escape into the main tank. Second, it allows water from the main tank to pass through the pellets, delivering available nitrate and phosphate to the bacteria growing the pellets. Additionally, it allows a return path for that water to reenter the main tank. Finally, it provides enough water flow through the pellets to keep them suspended or “Fluidized” within the water being treated. During normal function, the desired bacterial growth on the pellet surface creates a bacterial film. That film is sticky and without proper flow and motion, the pellets will stick to each other and clump up. Clumped pellets and lack of proper flow can lead to the generation of compounds such as sulphur dioxided which are detrimental to the aquarium. The water passing through the pellets is also sufficiently strong as to strip some of the bacterial film from the pellets. This stripped film exits the reactor where the bacteria can then be extracted from the water with another filter such as a protein skimmer, or they may be consumed by other tank inhabitants such as corals. By removing the bacteria that consumed the phosphate and nitrate within the tank water, those compounds are effectively eliminated from the tank
Current designs in use fluidize the pellets by utilizing an electric water pump to pump tank water at high velocity through the pellets inside a chamber separated from the tank water by the pump itself on one end and a screen on the other with openings sufficiently small as to prevent the vast majority of the pellets from escaping the reaction chamber. Water passing through the screen then reenters the main tank system. The biopellets are denser then water so they naturally sink to the the bottom of the chamber. In existing systems, the fluidizing is accomplished by directing the flow of the pumped water in the chamber into, or through the biopellets resting in the bottom of the reaction chamber. These devices direct the water from the top down, with the water stream deflecting off the bottom of the reactor causing up currents which fluidize the pellets, or from the bottom up through small holes which direct water current straight upward, lifting the pellets with them. Alternatively, fluidization has also been achieve with a combination of the above with the mechanical mixing of the pellets by a water flow driven stirring device. These methods of fluidization do not provide uniform or consistent suspension of the pellets within the system, or they rely on moving (mechanical) parts to do so. The present invention utilizes no moving parts and provides uniform fluidization of the pellets within the reactor.
The present invention comprises a biopellet reactor with a unique method of pellet fluidization. The reactor is setup and operated in the same way as existing reactors. It consists of an inlet pipe which directs water from an external water pump into the base of the reactor. The water is forced through a cyclonic fluidizing plate into the reaction chamber from below the pellets. The unique shape and configuration of the fluidizing plate creates upward pressure and a cyclonic effect on the water and pellets above it, causing the pellets to be fluidized in a uniform and controllable fashion. At the top of the reactor is screen plate that allows the water that has passed through the reactor to return to the tank through a pipe, while retaining the biopellets in the reaction chamber.
The distance of the exit hole from the outside edge of the fluidizing plate 19 is constant regardless of plate diameter. The width of the exit hole 20 is dependent upon expected flow rate of the biopellet reactor. The height of the exit hole is fixed to a size small enough to prevent the biopellets from passing through to the base chamber if the pump is turned off. Acceptable width is such that the summation of the surface areas of the exit holes is large enough to allow the total flow rate of water passing through the plate to match or exceed the flow rate necessary for proper fluidization of the biopellets.
During operation, water passes through the fluidizing plate from bottom to top. It enters the plate with an upward vector and the pass through holes alter the direction of flow to be parallel to the top surface of the plate. The position of the exit holes in the top of the plate near the outside walls of the reactor force the water to flow in a circular motion around the reactor chamber as it rises toward the top of the reactor. The biopellets are lifted above the fluidizing plate by the pressure created by the flow of water over the top surface of the fluidizing plate. This creates a layer of water above the plate which completely suspends the mass of pellets. The cyclonic motion of that layer causes the biopellets above it to spin and mix around the chamber. This rotation generates centrifugal force on the pellets which forces them toward the walls of the chamber. Gravity pulls the pellets back down toward the fluidizing plate. The combination of the uplifting force generated but the fluidizing plate, centrifugal and gravitational forces balance out to confine the mass of biopellets into a fully suspended band which is spinning and mixing within the chamber. The use of an external gate or ball valve to control the input flow of water can control the size, location and motion within the mass of biopellets.
Although the preceding description of the invention contains many details, it should not be taken as limiting the scope of the invention but rather providing illustration of a present working model. For example, the diameter of the fluidizing plate/media reactor and the number or size of the outlet holes can very depending on the overall size of the reactor. Small diameter reactors require fewer holes and smaller holes in the fluidizing plate to achieve the same functionality. Such alterations would not materially alter the nature of the invention and would in fact be necessary to achieve proper function. Thus, the scope of the invention should be fixed by the following claims rather then and specific examples provided.
This Application claims the benefit of U.S. Provisional Patent Application No. 62/118,609, filed Feb. 20, 2015, the entire contents of which is incorporated herein by reference.