Yokogawa EJA110A - Manual (Page 27)

IM 01C21B01-01E 5-2
5. INSTALLING IMPULSE PIPING
F0502.EPS
Nipple
Nipple
Process
connector
Ball head
lock nut
Pipe
Ball head
lock nut
Process connector
bolts
50 mm(2-inch) pipe
Pipes
3-valve
manifold
Impulse piping
Vent plug
(optional)
Stop valve
(low pressure side)
Equalizing valve
(balancing)
Stop valve
(high pressure side)
Figure 5.1.1b 3-Valve Manifold (Pipe-Mounting Type)
᭿ Direct-Mounting Type 3-Valve Manifold
(Figure 5.1.1c)
1) Mount the 3-valve manifold on the transmitter.
(When mounting, use the two gaskets and the four
bolts provided with the 3-valve manifold. Tighten
the bolts evenly.)
2) Mount the process connectors and gaskets on the top
of the 3-valve manifold (the side on which the
impulse piping will be connected).
Bolts
Process
connector
Gasket
Gasket
Process
connector
Bolts
Stop valve
Stop valve
3-valve
manifold
3-valve
manifold
Equalizing valve
Equalizing
valve
Stop valve
Impulse
piping
Impulse
piping
Stop valve
F0503.EPS
Figure 5.1.1c 3-Valve Manifold (Direct-Mounting Type)
NOTE
After completing the connection of the transmit-
ter and 3-valve manifold, be sure to CLOSE the
low pressure and high pressure stop valves,
OPEN the equalizing valve, and leave the
manifold with the equalizing valve OPEN.
You must do this in order to avoid overloading
the transmitter from either the high or the low
pressure side when beginning operation.
This instruction must also be strictly followed as
part of the startup procedure (Chapter 7).
5.1.2 Routing the Impulse Piping
(1) Process Pressure Tap Angles
If condensate, gas, sediment or other extraneous
material in the process piping gets into the impulse
piping, pressure measurement errors may result. To
prevent such problems, the process pressure taps must
be angled as shown in Figure 5.1.2 according to the
kind of fluid being measured.
NOTE
• If the process fluid is a gas, the taps must be
vertical or within 45
°
either side of vertical.
• If the process fluid is a liquid, the taps must be
horizontal or below horizontal, but not more
than 45
°
below horizontal.
• If the process fluid is steam or other condens-
ing vapor, the taps must be horizontal or above
horizontal, but not more than 45
°
above hori-
zontal.
[Gas]
Pressure
taps
Process
piping
[Steam] [Liquid]
45
°
45
°
45
°
45
°
45
°
45
°
F0504.EPS
Figure 5.1.2 Process Pressure Tap Angle (For Horizontal
Piping)