Emerson FISHER LR128 Series, Instruction Manual, Page: 6 / 28

BLOCK VALVE STRAINER BLOCK VALVE
TYPE MR98H
TYPE LR128
MAIN VALVE
TYPE 112 RESTRICTOR
A
C
D
ALTERNATE PILOT
EXHAUST PIPING
NON-RESTRICTIVE
VENTS AND PIPING
ALTERNATE PILOT
EXHAUST PIPING
TYPE MR98H PILOT
TYPE LR128
MAIN VALVE
TYPE 112 RESTRICTOR
D
C
A
CONTROL LINE
ALTERNATE CONTROL LINE
STRAINER
HAND VALVE
STRAINER
BLOCK VALVE
MAIN PRESSURE LINE
!
3. The standard pilot mounting position is as shown
in Figure 1. Rotate the bonnet (key 2, Figure 11) or
the pilot (Figure 16) for other mounting positions.
4. An upstream control line is required and must be
installed – as shown in Figure 3 – into the 1/8 NPT
connection in the pilot body assembly (Figure 16).
Do not make the upstream pipeline connection in
or directly downstream of a turbulent area such
as a swage or elbow. A filter or strainer may be
installed in the control line upstream of the pilot
to provide clean fluid. Inspect and clean this filter
regularly to make sure it is not plugged, which can
prevent proper pilot operation.
5. Run a supply pressure line from the upstream
pipeline to the restrictor inlet (use 3/8 NPT outer
diameter tubing or larger). Install a filter or strainer
upstream of the restrictor, if needed, to keep the
supply source from clogging the restrictor or pilot.
Inspect and clean this filter regularly to make sure
it has not been plugged which can prevent proper
relief valve or backpressure operation.
6. Apply a good grade of pipe compound to the
external pipeline threads for a threaded body
or use suitable line gaskets for a flanged body.
Use approved piping procedures when installing
the relief valve or backpressure regulator.
When used in relief valve service, the
Type LR128 may leak toxic chemical to
the environment. In toxic or hazardous
liquid service, leaked chemical may
accumulate and cause personal injury,
death or property damage due to
escaping fluid.
To prevent such injury or damage,
provide piping or tubing to vent the
hazardous liquid to a remote, safe
location away from air intakes or any
hazard-prone location. The exhaust
piping must be designed and installed to
guard against excessive flow restriction.
Protect the vent line or stack opening
against condensation or clogging.
For safety during shutdown, vent valves
are required immediately upstream
and downstream of the main valve on a
backpressure or bypass installation.
7. If system operation during maintenance is required,
install isolating and vent valves as needed.
Figure 3. Typical Type LR128 Installation Schematic
WARNING
A - VENT (TO DOWNSTREAM PIPING)
C - TO TYPE LR128 LOADING CHAMBER
D - PILOT SUPPLY (FROM UPSTREAM)
RELIEF PRESSURE CONTROL BACKPRESSURE CONTROL
BLOCK VALVE
NON-RESTRICTIVE
VENTS AND PIPING
ALTERNATE PILOT
EXHAUST PIPING
BLOCK VALVE
BLOCK VALVE
ALTERNATE PILOT
EXHAUST PIPING
TYPE MR98H
TYPE 112 RESTRICTOR
TYPE 112 RESTRICTOR
CONTROL LINE
ALTERNATE CONTROL LINE
TYPE MR98H PILOT
TYPE LR128
MAIN VALVE
TYPE LR128
MAIN VALVE
STRAINER
STRAINER
STRAINER
HAND VALVE
MAIN PRESSURE LINE
6
Type LR128