Triple drain apparatus for an aquaculture recirculation system

Abstract

Triple drain apparatus for an aquaculture system tank for reducing water input requirements and minimizing breakdown of solids whereby the solids are larger and more concentrated when removed from a solids settling device. Water flow is split by the apparatus into a side box fluid stream which flows into a side box coupled to the tank, and both a clean fluid stream and a high solids fluid stream which flow into a center drain. The center drain comprises a central stand pipe coupled to a clean water outlet, a sump coupled to a high solids fluid outlet and a collection plate separating the tank and the sump. The center drain may include a mortality trap coupled to a mortality outlet and the sump, whereby the collection plate separates the mortality trap from the sump, to provide means for easily removing dead fishes and large debris from the tank.

1 . Triple drain apparatus for installation in a tank of an aquaculture system, the tank having a substantially cylindrical tank side wall and a tank bottom wall and configured to receive incoming water entering the tank with a momentum substantially tangent to the tank side wall and a velocity of about 100-120 cm/sec, the triple drain apparatus comprising:
 a side box configured for attachment to an outside side wall of the tank distally from a bottom wall of the tank, the side box having at least a first compartment configured to receive a side box fluid stream from the tank and to expel the side box fluid stream for treatment;   a stand pipe having a first end and a second end, and configured for installation concentrically within the tank whereby the first end of the stand pipe is positioned below a surface of water in the tank and the second end of the stand pipe extends through the bottom wall of the tank to an outlet, the stand pipe having openings which are proximal to the bottom wall of the tank, when installed in the tank, for passing a clean fluid stream from the tank into the stand pipe, the openings being sized to prevent fish from passing into the stand pipe and to produce a clean fluid stream velocity of less than 10-20 cm/sec when the clean fluid stream passes into the stand pipe;   a conical sump configured for installation concentrically with the stand pipe and extending below the bottom wall of the tank whereby the conical sump is coupled to the bottom wall of the tank to permit a high solids fluid stream to pass from the tank into the conical sump, and including a collection plate having perforations sized to prevent the passage of fish and configured for separating the tank and the conical sump when the conical sump is installed whereby the conical sump temporarily contains solids passing through the collection plate in a high solids fluid stream; and,   a solids outlet proximal to a vertex of the conical sump and configured for directing the high solids fluid stream to a solids settling device.   
     
     
         2 . A triple drain apparatus according to  claim 1  and configured as an assembly. 
     
     
         3 . A triple drain apparatus according to  claim 1  and for installation in a tank having a conical bottom wall. 
     
     
         4 . A triple drain apparatus according to  claim 1  including a side box fluid stream valve means for controlling the volume of the side box fluid stream. 
     
     
         5 . A triple drain apparatus according to  claim 1  wherein the second end of the stand pipe couples to a clean fluid outlet, and the clean fluid outlet couples to a second compartment of the side box, wherein the second compartment of the side box is configured for receiving the clean fluid stream and for expelling the clean fluid stream from the second compartment for treatment. 
     
     
         6 . A triple drain apparatus according to  claim 1  wherein the openings in the stand pipe are slots. 
     
     
         7 . A triple drain apparatus according to  claim 5  including a clean fluid stream valve means for controlling the volume of the clean fluid stream entering the openings in the stand pipe. 
     
     
         8 . A triple drain apparatus according to  claim 1  wherein the perforations in the collection plate are slots. 
     
     
         9 . A triple drain apparatus according to  claim 1  wherein the solids settling device is a solids concentrator comprising:
 a generally cylindrical shaped portion vertically coupled to a generally conical shaped portion; 
 diffuser piping concentric to the solids concentrator between the cylindrical shaped portion and the conical shaped portion, the diffuser piping configured for coupling to the solids outlet and comprising a plurality of spaced openings to produce an upward laminar flow of fluid in the solids concentrator of less than 2 cm/sec when the high solids fluid stream passes through the diffuser piping into the solids concentrator; and, 
 a vertical pipe outlet having a first end positioned to receive fluid from the upward laminar flow of fluids and the second end coupled to a concentrator fluids outlet; 
 wherein solids in the high solids fluid stream concentrate in the generally conical shaped portion of the solids concentrator to be removed. 
 
     
     
         10 . A triple drain apparatus according to  claim 9  wherein the upward laminar flow velocity produced by the diffuser piping is less than 1 cm/sec. 
     
     
         11 . A triple drain apparatus according to  claim 9  wherein the solids concentrator further comprises a generally disc-shaped diffuser plate positioned proximal the first end of the vertical pipe outlet and oriented in a direction perpendicular to the laminar flow. 
     
     
         12 . A triple drain apparatus according to  claim 9  wherein the volume of the high solids fluid stream is controlled by a high solids fluid stream valve means. 
     
     
         13 . A triple drain apparatus according to  claim 1  and further comprising a mortality trap configured for installation concentric with the stand pipe and conical sump in the bottom wall of the tank whereby the mortality trap sits within a substantially circular recess in the bottom wall of the tank above the conical sump, the mortality trap having a substantially cylindrical trap side wall which couples with the conical sump, wherein the collection plate separates the mortality trap and the conical sump whereby the high solids fluid stream passes through the mortality trap into the conical sump and dead fish and solids collected by the collection plate are temporarily contained in the mortality trap. 
     
     
         14 . A triple drain apparatus according to  claim 13  and further comprising a mortality outlet configured for removing a mortality fluid stream containing dead fish and solids from the mortality trap, a first end of the mortality outlet configured for coupling to the trap side wall proximal to the collection plate and a second end of the mortality outlet configured for coupling to a third compartment of the side box upon installation of the apparatus in the tank whereby the third compartment receives the mortality fluid stream, the third compartment being configured to expel the mortality fluid stream from the third compartment for treatment through a screened third compartment outlet having openings sized to prevent passage of fish. 
     
     
         15 . A triple drain apparatus according to  claim 14  wherein the volume of the mortality fluid stream is controlled by a mortality fluid stream control means coupled to the mortality outlet.