The Aeration Unit comprises an open tank equipped with a paddle stirrer. A variety of diffusers is included. The dissolved oxygen content of the water in the tank is measured by means of an oxygen electrode and dissolved oxygen meter. The equipment consists of a base and backboard standing on four rubber feet. Mounted on the base is the clear acrylic water tank which has a capacity of 24.5 liters. On the front of the tank is a depth scale and at the base a drainage tap. The lid of the tank is partially removable to allow filling. On the fixed part of the lid are mounted the stirrer motor, stirrer and clamping positions for the temperature probe, oxygen probe and aerator tube. Air is supplied by an electrically driven pump through a control valve and flow meter to a diffuser, adjustable for position, within the tank. The meter supplied gives an additional direct reading of water temperature. Air is supplied to the tank by means of a pump with filter and silencer assembly is controlled by a valved flow meter discharging through the aerator tube. Three diffusers, sparger tube, treble airstone and single airstone, may be separately attached to the aerator tube. Operating from internal batteries, the meter may be used for field trials independently of the apparatus. Variable speed adjustment of the stirrer paddle provides different levels of turbulence in the tank. The oxygen/temperature meter is mounted on the backboard with the connecting leads to the appropriate probes.
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