Replacement Of Packing; Torque Specifications - Fisher MR95L Instruction Manual

MR95 Series
BODY SIZE
In. DN
1/4 - - - -
1/2 15
3/4 and 1 20 and 25
1-1/2 and 2 40 and 50
1. Reduce spring case bolt's torque by 30% when using Ethylenepropylene (EPDM) diaphragms.
10. If the unit has metal diaphragms (see Figures 4
and 5):
a. (Applicable only for the lower diaphragm head
of Types MR95H, MR95HT and MR95HD, 1-1/2
and 2 in. / DN 40 and 50.) Find the pusher
post (key 10) and place on a surface with the
larger flat surface down and the thread stem up
(metal diaphragm pusher post has a recessed
diameter in the bottom surface). Then, find
one smaller composition gasket (key 29) and
fit it over the threaded end of the pusher post.
Find and take one of the diaphragm heads and
slip it over the threaded end of the pusher post
with the chamfered side of the diaphragm head
toward the gasket. Take a second gasket and
place it over the threaded end of the pusher
post on top of the diaphragm head.
b. Replace one of the two large diaphragm gaskets
(key 19) on the surface of the body (key 1) that
will support the diaphragms (key 12). There will
be two diaphragms used per regulator, except
for Types MR95L and MR95LD, 1/4 NPT with
2 to 6 psi / 0.14 to 0.41 bar spring range setting
which use only one metal diaphragm (the
metal diaphragm is in between two diaphragm
gaskets). Another diaphragm gasket will be
placed on top of the second metal diaphragm.
The raised surfaces of the metal diaphragms
should be placed in the unit so that they are
facing toward the assembler (toward the spring)
except only when one metal diaphragm is
being used then the raised surface should be
facing down (towards the body). See Figure 2
as reference.
11. Reassemble in the reverse of the above
procedures. Lubricate the upper spring seat
(key 9) and the exposed threads of the adjusting
screw (key 15) with anti-seize lubricant. Install the
cap screws (key 16) in a crisscross pattern and
tighten to finger tight only.
12. To ensure proper slack in the diaphragm, install
the adjusting screw (key 15, for Types MR95L,
MR95H, MR95HP and MR95HT) or handwheel
(key 38, Types MR95LD and MR95HD), if
completely removed and turn it clockwise. This
16
Table 8. Torque Specifications
SPRING CASE BOLTS
(1)
FT-LBS N•m
6 to 8 8 to 11
10 to 13 13 to 18
24 to 30 33 to 41
40 to 50 54 to 68
ORIFICE
FT-LBS N•m
6 to 8 8 to 11
34 to 38 46 to 51
50 to 60 68 to 81
180 to 200 244 to 271
allows proper positioning of the diaphragm
(key 12) to permit full travel of the valve plug
(key 4). Finish tightening the cap screws (key 16).
See Table 8 for proper torque values.
13. Complete reassembly procedures and turn the
adjusting screw (key 15) or handwheel (key 38)
to produce the desired outlet pressure. For
Types MR95L, MR95H, MR95HP and MR95HT,
tighten the jam nut (key 17) to maintain the
desired setting.

Replacement of Packing

(Types MR95LD and MR95HD only)
Leakage around the adjusting screw may indicate
worn packing material. Follow the instructions below to
replace the packing rings.
1. Shut down the regulator. Refer to "Shutdown"
section for the proper procedure.
2. Take out the machine screw (key 41) and lift off
the washer (key 44) and handwheel (key 38).
3. Unscrew the packing box (key 32). Unscrew the
packing nut (key 35) and the packing follower
(key 34) off of the adjusting screw (key 33).
4. Unscrew and pull the adjusting screw (key 33) out
through the bottom of the packing box (key 32).
5. Pull out the old packing (key 36) and replace it with
three new packing rings. Replace the packing box
gasket (key 37). Lubricate packing box gasket with
general purpose Polytetrafluoroethylene (PTFE) or
lithium grease.
6. Reassemble the stuffing box unit by returning
the adjusting screw (key 33) to the inside of the
stuffing/packing box (key 32). Slip the packing
follower (key 34) onto the adjusting screw and
into the packing box. Screw on the packing nut
(key 35).
7. Put the stuffing/packing box (key 32) back onto the
spring case (key 2). Set the handwheel (key 38) and
washer (key 44) on the adjusting screw (key 33) and
screw in the machine screw (key 41).
PLUG GUIDE
FT-LBS N•m
50 to 58 68 to 79
75 to 90 102 to 122
100 to 125 136 to 169
170 to 200 230 to 271