Venturi Oxygenators are an essential piece of equipment for all recirculating hydroponic systems.
They require a pressurised flow to operate and function on the reserve pressure emitted from the main hydroponic recirculation pump.
The Venturi is a “T” shaped device which has a small internal orifice before an air inlet on the “T” branch. This creates a suction action as pressurised water flows through the orifice
The Venturi should be installed about 300mm below the surface of the tank solution on the bypass of a pump.
The pump bypass sends a proportion of pressurised nutrient solution back into the tank as it is fed out to the crop.
A 20mm pipe is attached to the “Air Inlet” on the Venturi. The tip of this pipe should be installed under the overhang/eave on the pump room roof so that the air that is sucked in, is dust free and cool and is well away from the surface of the tank where waste gas will be present.
As a pressurised solution is passed through the Venturi it creates a suction action which injects oxygen into the passing flow. This oxygen bubbles up under the surface of the tank solution.
Waste Gas Removal
Plants emit their waste material as a gas from the root system. This waste gas is heavier than air.
In recirculating NFT systems the waste gas will gradually make its way back to the mixing tank in the pump room as part of the gravity fed return solution.
When the Venturi injector is in operation it emits a vast quantity of bubbles beneath the surface of the mixing tank solution.
These fresh oxygen bubbles rise to the surface and force any stale waste gas towards the top of the mixing tank where it can be removed with an extraction fan mounted on the tank roof, or by or a natural breeze blowing through vents in the roof of the tank. The roofs of tanks should always be well ventilated for this purpose.
Oxygenation
The removal of the waste gas allows the gravity fed return solution to cascade through clean air as it falls onto the surface of the tank solution.
The combined process of a nutrient solution cascading through clean air and the injection of fresh air bubbles beneath it, greatly increases the dissolved oxygen content of the nutrient solution.
The Venturi also assists in mixing any nutrient stock solutions as they are added to the tank.
The suction side of the Venturi can also be connected to an ozone generator, and the suction action will draw any ozone from within the generator and inject it into the passing flow.
The Venturi is supplied with 40mm Inlets and Outlets and a 20mm Air Inlet Branch.
It should be a mandatory part of every pump room system.
Please talk to Pure Hydroponics for pricing and shipping.
