Observator RIMCO RIM-FVU User manual

Manual | RIM-FVU Field Verification Unit (FVU)
Status: Final | Not confidential
Page 1 | 13
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Manual
RIM-FVU Field Verification Unit (FVU)
Version: 20200309
Status: Final
Confidentiality: Not confidential
Date: 09 March 2020
Author: Ludovic Grosjean
www.observator.com

Manual | RIM-FVU Field Verification Unit (FVU)
Status: Final | Not confidential
Page 2 | 13
V20200309
Document history
The Observator range is in continuous development and so specifications may be subject to change
without prior notice. When in doubt about the accuracy of this document, contact the Observator Group.
Reference documents
Type of document / tool
Product type and name (incl. url)
Manual
RIM-FVU
Revision history
Date
Amendments
Company, position
2017-07-31
Initial document creation
Observator Australia,
Document Controller
2017-10-24
Updated warranty conditions
Observator Australia,
Document Controller
2018-04-09
Introduced document control
Observator Australia,
Document Controller
2019-08-09
Quality review
Observator Australia,
Operation Manager
2019-08-27
Update product name
Observator Australia,
Document Controller
2019-08-30
Compress document images
Observator Australia,
Document Controller
2020-01-30
Updated document format
Observator Australia,
Document Controller
2020-03-09
Updated maintenance section
Observator Australia,
Document Controller
Procedure sign-off:
Date
Company, position
Status
2019-07-15
Observator Australia, Document Controller
Finished
2019-12-06
Observator Australia, Managing Director
Approved
2020-02-10
Observator Group, Communication Officer
Approved
Distribution list
Date
Company, position

Manual | RIM-FVU Field Verification Unit (FVU)
Status: Final | Not confidential
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Summary
Thank you for purchasing an Observator Instruments Field Verification Unit (FVU). The RIMCO RIM-FVU
is a simple unit for the verification of tipping bucket rain gauges calibrations in the field. The FVU is ideal
for hydrologists who do rain gauge maintenance checks in remote locations. The RIM-FVU is
manufactured to exact tolerances and can produce repeatable volumes when used in accordance to this
manual. As such, the RIM-FVU can be used as a primary standard in field and laboratory calibrations of
rain gauges.
The RIM-FVU comes with an approximate 200mm/hr nozzle as a standard.

Manual | RIM-FVU Field Verification Unit (FVU)
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Table of contents
1Applications .........................................................................................................................5
2Safety ....................................................................................................................................6
3Specifications.......................................................................................................................7
4What you will find in the box..............................................................................................8
5Calibration............................................................................................................................9
5.1 Calibration validation........................................................................................................................... 9
5.2 Maintenance......................................................................................................................................12

Manual | RIM-FVU Field Verification Unit (FVU)
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1 Applications
Typical use of the RIM-FVU device includes many types of applications:
1. In the factory.
2. Upon receipt by the reseller or end user.
3. In the field.
RIM-FVU products are also ideal for rain gauge calibrations and validations.

Manual | RIM-FVU Field Verification Unit (FVU)
Status: Final | Not confidential
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2 Safety
For correct functioning of the Observator RIM-FVU, the calibration unit must be installed
according to the installation instructions.
Always clean and dry the RIM-FVU after use.
After end of life, please dispose of this product according to your local regulations or
return it to the manufacturer.

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3 Specifications
Field Verification Unit dimensions
Length
374mm
Diameter
60mm
Weight
564.5g
Capacity
653mls
Nozzle flow
200mm/hr (approximately)
Material body
Polyvinyl Chloride (PVC) and PERSPEX®
Material vent / nozzle
Stainless steel
Material funnel mount
Acrylic
Case details
Case construction
Acrylonitrile Butadiene Styrene (ABS)
Length
515mm
Width
434mm
Depth
225mm

Manual | RIM-FVU Field Verification Unit (FVU)
Status: Final | Not confidential
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4 What you will find in the box
When the product is delivered, this is what you will find in the box:
Items found in the box
Field Verification Unit
RIM-FVU
Allen key
Funnel mounting plate
Instrument case
Nozzle
Allen key
Funnel mount
FVU cartridge

Manual | RIM-FVU Field Verification Unit (FVU)
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5 Calibration
5.1 Calibration validation
Rain gauge calibration using the RIM-FVU is performed as outlined below. Repeat the calibration check at
least once for more accurate results.
1. Unscrew the nozzle from the RIM-FVU and make sure the valve, on the opposite end is closed.
2. Fill in the cylinder with clean water until the top.

Manual | RIM-FVU Field Verification Unit (FVU)
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3. Reattach the nozzle to the RIM-FVU.
4. Flip the RIM-FVU and position it on top of the rain gauge through the mounting plate on the catch of
the rain gauge.
Note: Wet the rain gauge system prior to the calibration check to try to minimise any irregularities with
your readings.

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5. Open the siphon valve. The water will flow out of the RIM-FVU to the tipping bucket rain gauge at a
predetermined rate. The number of tips can either be audibly counted or digitally counted (these can be
bought as an option), or the counts can be retrieved from a data logger and checked against calibration
specifications.
6. With an approximate volume of 653mls, the tip count should be around 101, but can vary with each
unit. Check the label for expected tip counts.
7. The Field Verification Unit comes with a 1.5mm nozzle orifice as standard for field verification. The unit
can be ordered with a 0.9mm orifice nozzle if it is necessary to perform a calibration to the Australian
Standard (AS3580.14). Drain time is around six minutes with a 1.5mm nozzle and up to twenty minutes
with the 0.9mm nozzle.
8. You will need to do the test repeated times to achieve ±2 tips counted on two progressive runs*, then
the instrument is within acceptable calibration limits. If not, then the tipping bucket limit screws will have
to be adjusted until an acceptable result is obtained after several passes
(*) Special note:
Please be aware that tip counts can vary
from tube to tube.

Manual | RIM-FVU Field Verification Unit (FVU)
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5.2 Maintenance
The RIM-FVU is relatively maintenance-free apart from routine cleaning. This is performed with the
following:
•fresh water;
•warm water;
•mild soapy solution.
Manually clean the Field Verification Unit using a fine tool to clean the nozzle hole.
Figure 5.A: The tool should fit in the hole as a close fit (not too tight and not too loose).
Important: Do not use any solvent as it will damage the FVU.

Manual | RIM-FVU Field Verification Unit (FVU)
Status: Final | Not confidential
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© Copyright –Observator Group
Since 1924 Observator has evolved to be a trend-setting developer and supplier in a wide variety of
industries. Originating from the Netherlands, Observator has grown into an internationally oriented
company with a worldwide distribution network and offices in Australia, Germany, the Netherlands,
Singapore and the United Kingdom.
www.observator.com