Emerson PENBERTHY LC Series Instrucciones de instalación, uso y mantenimiento - Página 5
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PENBERTHY SERIES LC FLAT GLASS GAGES
INSTALLATION, OPERATION AND MAINTENANCE INSTRUCTIONS
5.4 Nut retorquing
Nut re-torque is vital to the operation of a liquid
level gage because gaskets take permanent
'set' under initial bolt loading at assembly.
Tightening of nuts before installation to values
specified in Table 3 is necessary to insure
pressure retaining capabilities of a liquid
level gage to specific design ratings. The user
must refer to the liquid level gage model and
assembly number and to the purchase order
or tag to determine materials of construction.
SAFETY INSTRUCTIONS
Before placing the liquid level gage into initial
operation, torque values must be verified. From
factory testing to installation, gasketing may take
'set' reducing closure force. Retorquing before
operation reduces chance of leakage or gasket
'blow out'.
Using a torque wrench, tighten nuts in 5 ft·lb
(7 Nm) increments following the 'Z' pattern
sequence in Figure 1, until the torque values
shown in Table 3 for the specific liquid level
gage are reached. For multiple section gages,
torque the center section(s) and progressively
work toward the ends of the gage.
If bolting, gasketing or glass on any repaired
section of a multi-section gage is disturbed,
all sections must be checked for integrity and
retorqued as necessary.
WARNING
Failure to comply with the proper torquing
sequence or force value can lead to leakage,
gasket blow-out or glass breakage resulting in
gage failure, serious personal injury or property
damage.
Note: depending on gage size there may be
less bolting than shown in Figure 1. Start at the
center and follow the 'Z' pattern outward to the
limit of bolting on a specific gage.
TABLE 3 - BOLT TORQUE VALUES
Gasket material
RLC and TLC w/Grafoil
(standard)
®
RLC and TLC w/non-asbestos (optional)
Top-chem 2000
®
PTFE and PCTFE (Kel-F
)
®
25% glass filled PTFE
All models with FKM (Viton
) or elastomeric (optional)
®
TLC with PCTFE (Kel-F
) shields (optional) 0.063" (1.6 mm)
®
5.6 Belleville washers (optional)
Belleville washers are used to reduce the need
to retorque nuts. This is especially important
for gages subject to pressure and/or thermal
cycling. The conical washers allow for material
expansion and contraction while maintaining
axial bolt loading and, therefore, compression
on the gasket.
Model RLC gages require 7 washers per nut,
model TLC gages require 4 washers per nut
(8 per bolt). Washers should be assembled with
the cupped side facing the gage cover. Refer to
Figure 2 for proper washer assembly.
Note: the following procedure is to be done on
only one side of a transparent gage.
Using a torque wrench, tighten nuts in 5 ft·lb
(7 Nm) increments following the 'Z' pattern
sequence found in Figure 1 until the torque
values shown in Table 3 are reached.
6 OPERATION
Before initializing liquid level gage operation,
check that all installation procedures
have been completed. Use only qualified,
experienced personnel who are familiar with
liquid level gage equipment and understand
the implications of the tables and all the
instructions thoroughly. Check to determine
that all connections are pressure tight. Ensure
that nuts have been retorqued to their proper
values as specified in Table 3. Remove self stick
caution tape from the glass and inspect to be
sure that glass is clean and free of any damage
such as cracks, scratches, pits and chips.
ft·lb (Nm)
20 to 25 (27 to 34)
35 to 40 (48 to 54)
20 to 25 (27 to 34)
20 to 25 (27 to 34)
19 to 22 (26 to 30)
10 to 15 (14 to 20)
20 to 25 (27 to 34)
FIGURE 1
Nut tightening sequence
FIGURE 2
Belleville washer position
Belleville
washer
Cover
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