3-14
Chapter 3 Starting and Stopping this Device
3-2-3 Open Tank and Sealed Tank (Dry Leg) Liquid Level Measurement
(1) Preparing for Operation
(i) Important points
Warning
When clearing vents and drains, check the direction in which material will come out in
order to avoid any contact with the human body. There is a danger of scalding and other
harmful health effects. If the process fluid is harmful to the human body, take safety
measures such as wearing goggles or a mask so that it does not adhere to the skin or the
eyes, become inhaled, etc.
Caution
Check that the process is in manual control mode. If it is in automatic control mode, be
sure to switch it to manual control mode before starting work.
In terms of piping, before commencing operation of this device as shown below, the
master valves, drain valves, drain plugs, gas vent plugs, and the stop valve of the three-way
manifold valve must be closed on both the high pressure and low pressure sides. In
addition, check that the equalizer valve of the three-way manifold valve is open (see
Figures 2-37 and 2-38).
(ii) Calculating the setting range
To find the setting range based on calculation, see section 3-10.
(iii) Zero point check and calibration
Procedure
(1) Open the high pressure side and low pressure side gas vent plugs, drain plugs, and stop valves
of the three-way manifold valve, and open the pressure-receiving part to the atmosphere. At
this time, if fluid remains in the pressure-receiving part, remove it, being careful not to damage
the diaphragm.
(2) Using the communicator, check the device output. If the output is not zero, calibrate the zero
point. For information regarding the zero point calibration procedure, see the operation manual
for the communicator.
(3) After finishing calibration and checking, close the high-pressure side and low-pressure side gas
vent plugs, the high-pressure side drain plug, the high-pressure side stop valve for the three-way
manifold valve, and the equalizer valve.
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