PILOT SUPPLY CONNECTION: 1/4 NPT PIPE
CONNECTS TO UPSTREAM PILOT SUPPLY TAP
LOADING CONNECTION: 1/4 NPT PIPE CONNECTS TO
TYPE LR128 DIAPHRAGM LOADING PORT
OUTLET CONNECTION: 1/4 NPT PIPE
CONNECTS TO PILOT INLET CONNECTION
OPTIONAL LOADING CONNECTION:
1/4 NPT NORMALLY PLUGGED
11B5004-A
!
Figure 4.
Type 112 Restrictor
Maintenance
Relief valve or backpressure regulator parts are
subject to normal wear and must be inspected
periodically and replaced as necessary. Due to the
care Emerson takes in meeting all manufacturing
requirements (heat treating, dimensional tolerances,
etc.), use only replacement parts manufactured or
furnished by Emerson. Also, when lubrication is
required, use a good quality lubricant and lightly coat
the recommended part.
The frequency of inspection and parts replacement
depends upon the severity of service conditions,
applicable codes and government regulations and
company inspection procedures. Table 8 lists possible
relief valve or backpressure regulator issues and
solutions for them.
Regular inspection of the restrictor
is recommended to ensure optimum
performance. Refer to the Type 112
Restrictor Maintenance section.
Likewise, debris in the process fluid
may clog the restrictor. Install strainer
upstream of the regulator to prevent
debris from clogging the restrictor.
Regular inspection, maintenance and
cleaning of the strainer is recommended
to ensure optimum performance.
Recommended Type 112 Restrictor
Settings and Restrictor Setting Guide
(Table 4 and Figure 5)
This guide can be used to adjust performance
according to application conditions. The recommended
initial setting is “6” for the 1, 2 and 3 in. sizes and “8”
for the 4 in. size (see Table 4).
WARNING
CAUTION
Type LR128 Main Valve Trim
Parts Maintenance
Instructions are given for complete disassembly and
assembly. The main valve may remain in the pipeline
during maintenance procedures. Key numbers are
referenced in Figures 11 through 15.
Avoid personal injury or damage
to property from sudden release of
pressure or uncontrolled process
fluid. Before starting to disassemble,
carefully release all pressures
according to the Shutdown procedure.
Use gauges to monitor inlet, loading
and outlet pressures while releasing
these pressures.
Disassembly
Disassembly of Type LR128
1. Shutdown, isolate and depressurize the main valve
and pilot according to the shutdown procedure.
2. Remove the cap screws (key 3). Lift up and
remove the bonnet (key 2) from the body (key 1).
Provide adequate support to the bonnet
when disassembling Type LR128
relief valve or backpressure regulator
installed in a vertical installation or
other application where the bonnet is
not oriented upward. Without adequate
support, the bonnet may fall and cause
physical injury when the cap screws
are loosened.
8
Type LR128