Fisher 4195 KB Series Instruction Manual page 61

4195KA, KB, and KC Series
5. Tighten the machine screw (key 98) and the set
screw in the hex nut to fasten the drive bracket as-
sembly in that position.
Setting the Capsular Element Travel Stops
1. For the full span stop—Apply process pressure
equal to 5 percent greater than capsular element
range. Then perform the following as appropriate:
For positive or compound pressure with a three-
capsule stack, loosen the machine screws (key 139)
that secure the travel stop (key 83) to the mounting
plate (key 77). Slide the travel stop until it is just touch-
ing the end of the capsule stack. Tighten the travel
stop mounting screws to lock it into position. Decrease
the input pressure to 100 percent of the capsular ele-
ment range and make sure the capsule stack is not
contacting the travel stop (key 83).
For positive or compound pressure with a two-
capsule stack, loosen the set screw (key 87) in the
travel stop nut (key 86) between the travel stop (key
83) and the capsule stack. Slide the nut along the dia-
phragm capsule extension (key 130) until it just
touches the travel stop (key 83). Tighten the set screw
to lock the travel stop nut in position. Decrease the
input pressure to 100 percent of the capsular element
range and make sure the travel stop nut is not contact-
ing the travel stop (key 83).
For vacuum pressure, loosen the set screw (key
87) in the travel stop nut (key 86) on the end of the
diaphragm capsule extension (key 132 or 133). The
nut is located on the opposite side of the travel stop
(key 83) from the capsule. Slide the nut along the dia-
phragm capsule extension until it just touches the trav-
el stop (key 83). Tighten the set screw to lock the trav-
el stop nut in position. Decrease the vacuum to 100
percent of the capsular element range and make sure
the travel stop nut is not contacting the travel stop
(key 83).
2. For the zero stop—perform the following as ap-
propriate:
If the lower limit of the capsular element range is
0 psig, adjust the process pressure to 0 psig. Slide the
zero travel stop nut (key 86) along the diaphragm as-
sembly extension until it is approximately 1/64-inch
(0.4 mm) away from the travel stop. Tighten the set
screw to lock the travel stop nut in position.
If the lower limit of the capsular element range is
other than 0 psig, adjust the process pressure to 5
percent below the capsular element range lower limit
and slide the travel stop nut (key 86) along the dia-
phragm extension until it just touches the travel stop
(key 83). Tighten the set screw. Increase the input
pressure to the capsular element range lower limit and
5–28
make sure the travel stop nut is not contacting the
travel stop (key 83).
Aligning the Capsular Element Linkage
1. Adjust the process pressure to 75 percent of the
capsular element range. The drive flexure (key 79)
should be straight and horizontal. If it is not, proceed
as follows:
a. Loosen the screw on the pivot adjustment arm
on the long pivot clevis assembly (key 78) and the
two screws mounting the drive flexure.
b. Adjust the length of the pivot adjustment arm so
that the drive flexure is parallel to the centerline of
the capsules. Tighten the screw to set the length of
the pivot adjustment arm in that position.
See figure 5–20. The adjustment arm of
the long pivot clevis assembly is con-
nected to a shaft that turns on bushings
at each end of the shaft. In the next
step, position the shaft so that both
bushings ''float'' inside the bearings
and do not rest against the end of either
bearing.
c. Before retightening the drive flexure screws,
hold the long pivot clevis assembly shaft in the
middle of the bushing end play. Be sure neither
bushing is resting against the inside end of either
bearing.
d. Tighten the drive flexure screws to hold the piv-
ot clevis assembly shaft in position.
2. Set the linearity adjustment screw on the short piv-
ot clevis assembly so the two arms of the short pivot
clevis assembly are parallel. The linearity adjustment
screw should be near the center of its slot.
3. Make certain that the process pointer and pointer
subassembly are aligned as shown in figure 5–15. If
not, loosen the zero adjustment locking screw and ad-
just the process pointer zero adjustment screw to align
the process pointer and pointer subassembly. Tighten
the zero adjustment locking screw.
4. Adjust the process pressure to 50 percent of the
capsular element range.
5. Loosen the screw on link 5 (key 88) and adjust the
link length so that the pivot arms of the short pivot cle-
vis assembly (key 89) and the long pivot clevis assem-
bly (key 78) are parallel. Tighten the screw.
6. Complete the maintenance calibration by perform-
ing the zero and span adjustments in the following pro-
cedure.
Note