Yokogawa EJX115A - Manual (Page 26)

<5. Installing Impulse Piping>
5-1
IM 01C25K01-01E
5. Installing Impulse Piping
5.1 Process Piping Installation
Precautions
The manifold contains a small-bore orifice. For
the transmitter of a high pressure connection right
side, the orifice is placed facing such a direction
as to enable normal flow measurement when fluid
is flowed from right to left (as viewed from the
front). If the orifice is removed from the manifold,
it must be replaced facing the correct direction.
(For disassembly and reassembly procedures, see
Subsection 8.4.4)
Pay careful attention to the following points when
routing the process piping and connection the
process piping to the transmitter.
5.1.1 Connecting Process Piping to the
Transmitter
(1) Confirming the Process Fluid Flow
Direction (Figure 5.1)
The mark “ ” on the manifold indicates the
direction in which the process fluid is flowed (from
right to left). When connecting the process piping
to the process connector, confirm the process fluid
flow direction.
F0501.ai
Flow direction(from right to left)
Manifold
Orifice name plate
Process connector
(low pressure side)
Process connector
(high pressure side)
Process connection
(outflow side)
Process connection
(inflow side)
Bolt
Figure 5.1 Manifold and Flow Direction Indication
(2) Tightening the Process Connector
Mounting Bolts
The transmitter is shipped with the process
connector mounting bolts only loosely tightened.
After connecting the process piping, tighten these
bolts uniformly to prevent leaks with a torque of 39
to 49 N·m {4 to 5 kgf·m}.
(3) Removing the Process Connector Port
Dustproof Cap
The process connector port threads are covered
with a plastic cap to exclude dust. This cap must be
removed before connecting the piping. (Be careful
not to damage the threads when removing this cap.
Never insert a screwdriver or other tool between the
cap and port threads to remove the cap.)
5.1.2 Routing the Process Piping
(1) Relationship between Process Fluid
and Manifold Locations (For the vertical
impulse piping type)
If condensate (or gas) generated in the process
piping were allowed to accumulate, then it would be
necessary to remove it periodically by opening the
drain (or vent) plug. However, this would generate a
transient disturbance in the pressure measurement.
Therefore, the process piping must be routed so
that any condensate (or gas) generated in the
process piping will not accumulate in the pressure-
sensing assembly of the transmitter.
NOTE
• If the process fluid is a gas, then as a rule the
manifold must be located at the downside of
the pressure-sensing assembly. (Figure 5.2)
• If the process fluid is a liquid, then as a rule
the manifold must be located at the upside of
the pressure-sensing assembly. (Figure 5.3)
(2) Pipe Size for Process Piping
Use a 15 mm (1/2-inch) pipe for process piping
connection to the process connector.