Fish grow best if a constant oxygen level is maintained in the tank, but the consumption by the fish varies according to what they eat and how active they are. To maintain as constant oxygen level as possible, different amounts of oxygen have to be dosed at different times.
The AGA oxygen dosing cabinet is designed to do just that. Emphasis is placed on its simple, flexible structure, with the option to expand with additional modules if the conditions change.
Function
The dosing cabinet distributes and controls the oxygen from the distribution network to the tank using the customer’s own PLS system. The dosing cabinet is divided into two separate sections, one for normal operation and one for emergencies. The oxygen used for operation is dosed through two rotameters. One of the rotameters feeds oxygen for normal consumption and has to be adjusted gradually according to the oxygen consumption. The other rotameter is fitted in series with a solenoid valve. This valve is controlled by the output saturation in the tank and opens to allow additional oxygen when needed, to keep the oxygen saturation at a constant level in the fish tank.
Constant oxygen levels
This way the oxygen level for the fish can be kept at a constant level at all times which then will keep the oxygen consumption as low as possible. The oxygen flow through both rotameters are adjusted manually by a built-in needle valve in the rotameter.
Emergency oxygen
Should any problems occur with operation of the fish tank like a stop in the water flow or a drop in the oxygen level the emergency solenoid valve will open and distribute oxygen to the water by means of perforated hoses located at the bottom of the tank.. The oxygen distribution is set by means of a needle valve on the emergency outlet in the dosing cabinet. The dosing cabinet is controlled by the customer’s PLS system, which opens and closes the solenoid valves when needed. Alternatively, the solenoid valves can be connected to the main power supply and will open automatically in the event of a power failure.
The illustration shows a cabinet for three tanks, with distribution for operating oxygen and emergency oxygen. This cabinet has a separate pressure regulator for emergency oxygen (optional feature).
