Yokogawa EJA110A - Manual (Page 33)

IM 01C21B01-01E 7-1
7. OPERATION
7. OPERATION
7.1 Preparation for Starting
Operation
The Model EJA110A, EJA120A and EJA130A
pressure transmitter measures the flow rates and the
pressure of liquids, gases, and steam, and also liquid
levels. This section describes the operation procedure
for the EJA110A as shown in Figure 7.1 (vertical
impulse piping type, high-pressure connection: right
side) when measuring a liquid flow rate.
NOTE
Check that the process pressure tap valves,
drain valves, and 3-valve manifold stop valves
on both low pressure and high pressure sides
are closed, and that the 3-valve manifold equal-
izing valve is opened.
(a) Follow the procedures below to introduce process
pressure into the impulse piping and transmitter.
1) Open the low pressure and high pressure tap valves
to fill the impulse piping with process liquid.
2) Slowly open the high pressure stop valve to fill the
transmitter pressure-detector section with process
liquid.
3) Close the high pressure stop valve.
4) Gradually open the low pressure stop valve and
completely fill the transmitter pressure-detector
section with process liquid.
5) Close the low pressure stop valve.
6) Gradually open the high pressure stop valve. At this
time, equal pressure is applied to the low and high
pressure sides of the transmitter.
7) Check that there are no liquid leaks in the impulse
piping, 3-valve manifold, transmitter, or other
components.
(b) Venting Gas from the Transmitter Pressure-detector
Section
Since the piping in the example of Figure 7.1 is
constructed to be self-venting, no venting operation
is required. If it is not possible to make the piping
self-venting, refer to Subsection 7.5 for instructions.
Leave the equalizing valve open even after venting
gas.
(c) Turn ON power and connect the BT200.
Open the terminal box cover, and connect the
BT200 to the SUPPLY + and – terminals.
(d) Using the BT200, confirm that the transmitter is
operating properly. Check parameter values or
change the setpoints as necessary. See Chapter 8 for
BT200 operation.
If the transmitter is equipped with an integral
indicator, its indication can be used to confirm that
the transmitter is operating properly.
F0701.EPS
Orifice
Tap valve
(high pressure)
Tap valve
(low pressure)
3-valve manifold
Drain valve
(high pressure)
Stop valve
(low pressure)
Stop valve
(high pressure)
Equalizing valve
Figure 7.1 Liquid Flow Measurement