These small propeller type meters are supplied with two propellers, one for very low flows (up to 0.3 m/s) and another for higher flows (up to 2.0 m/s) .
These small propeller current meters (Small Ott, Oss PC1 and Seba Mini) are useful for measuring very low flows, as long as the water isn't too shallow.
They have a propeller attached to a horizontal shaft and output one contact closure per revolution. The small Ott C1 has wiping type contacts and the C2 a magnetic reed switch.
These meters are quite delicate and are shipped in a metal box with two propellers, oil, a dismantling tool and a Gurley wading rod adapter.
The meters are rated at NIWA's rating tank located just north of Christchurch at Kainga. We rate the meters on a Gurley wading rod, unless specifically requested otherwise. Therefore gaugings should also be done on this type of rod.
The meter connects to a counting device, such as the NIWA Current Meter Counter, with a simple cable.
We can advise on, supply, hire, service and calibrate small propeller type current meters and can supply accessories from our Christchurch store.