Field Calibration Unit for Tipping Buckets

In response to hydrologists requests for a device to calibrate 8" (203 mm) Tipping Bucket Gages in the field, Rickly Hydrological has developed a Field Calibration Unit. It is a light, portable device that allows the hydrologist to perform calibration tests effectively. The advantage of using a Field Calibration Unit is that Tipping Bucket Gages can remain fixed in their location and are therefore only out of service for a very short period of time.

To calibrate a rain gage, the Field Calibration Unit nozzle is unscrewed from the cylinder, which is in turn filled with water to the very top. The nozzle is then screwed back on the cylinder and placed through the holding plate which sits on the catch of any Tipping Bucket Gage.

When the tap on the Field Calibration Unit is closed, the air is entrapped in the cylinder. When the tap is turned, a vacuum is created and the water is released down through the nozzle and into the Tipping Bucket Gage. A preset volume (653 ml) water will discharge through the Tipping Bucket Gage. This process is to be repeated a second time for accurate calibration. Calibration conforms to ISO 7309 specifications.