Yokogawa EJA115 - Manual (Page 25)

IM 01C22K01-01E 5-1
5. INSTALLING IMPULSE PIPING
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 9.4.4)
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 Direc-
tion (Figure 5.1.1)
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.EPS
Flow direction(from right to left)
Manifold
Orifice name plate
Process connector
(low pressure side) Process connector
(high pressure side)
Process connection
(outflow side)
Bolt
Process connection
(inflow side)
Figure 5.1.1 Manifold and Flow Direction Indication
(2) Tightening the Process Connector Mount-
ing Bolts
The transmitter is shipped with the process connector
mounting bolts only loosely tightened. After connect-
ing 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 im-
pulse piping type)
If condensate (or gas) generated in the process piping
were allowed to accumulate, then it would be neces-
sary 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 conden-
sate (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 5.1.2)
• 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 5.1.3)