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.
1001-097
Field Calibration Unit with 100 mm/hr Discharge Nozzle
2 lbs.
1001-099
Field Calibration Kit c/w 50, 100, 200, 300 & 500 mm/hr.
Nozzles 2 lbs.
1001-100
50 mm Nozzle 0.2 lb.
1001-101
100 mm Nozzle 0.2 lb.
1001-102
200 mm Nozzle 0.2 lb.
1001-103
300 mm Nozzle 0.2 lb.
1001-104
500 mm Nozzle 0.2 lb.
The Model 3512 Calibration Unit is a laboratory device
that when connected to a water supply, will discharge a
pre-set volume (653 ml) of water through one or two
Tipping Bucket Gages and display the number of tips.
International Standards Performance Specifications have
been set for the 200 mm and 8" (203 mm) standard tipping
bucket gages.
The outer enclosure of the tipping bucket gage is
removed before being placed on the mounting table. While
observing the level on the gage, the leveling knobs are
adjusted underneath the mounting table to level the rain
gage.
The siphon is then removed from the enclosure of the
tipping bucket rain gage and cleaned thoroughly. And then
is screwed directly into the siphon coupling on the
calibration stand.
Calibration is started by turning on outlet valve and
recording the number of tips after all the water is
drained from the container.
The gage is then adjusted to achieve the correct number
of tips in accordance with the gages calibration
specifications. This process is repeated for various
nozzle sizes and a minimum of three runs is recommended
for each nozzle.
1001-110
Double Calibration Unit 140
lbs.
