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10. Building a flowmeter pit
G.L.
Transducer
s
Stainless Steel Band
V path method: d+1200mm
Z path method: d/2+1200mm
- In principle, when measurement is of underground pipe, it is suggested to prepare dedicated
flowmeter pit.
- It is not necessary to prepare a flowmeter pit in the case of indoor or outdoor piping, but proper footing
should be planned for transducer mounting and equipment adjustments where the pipe is located
high off the floor or when pipe diameter is large.
Building a flowmeter pit
1. Select pit site (taking into consideration the following points)
1) Straight section of pipe is required for installation of transducers as explained under Part 5.
2) Consult manufacturer if an adjustable valve or pump is used.
3) To prevent noise interference or signal attenuation, coaxial cable used transducers and main
unit should be less than 30m.
2. Size and construction of flowmeter pit
1) Using above schematic as reference, determine size of flowmeter pit based on actual piping
position and conditions. Height of pit should allow person to stand while working.
2) Implement countermeasures for floods such as drainage gutters, etc. (Install water pump where
water is liable to accumulate or flood.)
3) Consult Manufacturer for other specific conditions. (Above dimensions are ideal and not the
minimum required.)
Transducer installation
1. Strip paint/coating from piping surfaces at transducer mounting locations and fix transducers
on piping using the accessory mounting fixtures. When mounting transducers according to the
"V" method, the distance separating the transducers should be about the diameter of the pipe.
If the "Z" method is used, the distance should be one half of the diameter.
2. After installing and adjusting the transducers, remove transducer mountings, and coat pipe
surface with anti-rust paint.
16
Manhole
Water drainage 500×500×d300
Coaxial cable
G.L.
Flowmeter Pit
>600mm
Pipe Dia (d)
Fastening
Fixture
Foot Step
>600mm
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