D-1401 & D-1402 Portable Metering System Installation and Operation Guide • 03-17
14
3.4
REM OVAL OF THE M ETER
CAUTI ON
Remember, the meter may be under high pressure, and while removal of the meter is basically the
reverse of the insertion procedure detailed above, care must be taken to ensure that the meter is
supported against the pipe pressure before the position clamping nut is loosened. Failure to do this
will allow the pressure to suddenly and rapidly force the meter from the pipe causing serious injury.
CAUTI ON
Prior to removal of the meter, make sure that you are standing on a secure platform and have both hands
available to manipulate the flow meter.
First support the flow meter against the pipe
pressure by holding the electronics enclosure firmly
in hand BEFORE loosening the position clamping
nut.
The effort which will be required is the same as
that required for insertion of the meter and should be
calculated according to the formula in the prior section
covering insertion of the meter. This effort will be 0.11
times the pipe pressure.
If your footing is not secure,
or if your ability to hold the meter limited for any
reason, DO NOT loosen the clamping nut.
SLOWLY
loosen the position clamping nut and
carefully and
slowly
allow the pressure to force the meter out of the pipe.
This is not at all difficult, but you must not let go of the meter until it is fully withdrawn into the
hot tap adapter. After the meter is completely withdrawn, you may close the isolation ball valve.
The main cause of damage to meters comes from accidentally closing the valve on the turbine
assembly. To avoid this, gently rotate the meter by twisting the electronics enclosure back and
forth (twist the stem, do not bend it) while you slowly close the valve. If the valve touches any
part of the meter, you will feel it as you are twisting the meter. If the valve touches anything, it
means the meter is not fully withdrawn. Usually a gentle twisting motion while withdrawing the
meter will clear any obstruction and permit the meter to withdraw completely. (Excessive build-
up on the stem may require the hot tap ‘ O’ ring to be lubricated with silicone.)
After the valve is completely closed, you can safely unscrew the hot tap adapter from the valve.
Partially unscrew the adapter and allow pressure to vent from the hot tap adapter. There will be
very little water in the hot tap adapter; however, a small bucket or pan should be held under the
valve to catch any spilled water.
!
!