TITLE:
NO.:
KEROTEST MODEL-1
REV.: 10
GATE VALVE
DATE: 7/12/07
OPERATIONS MANUAL
PAGE: 10 OF 35
This report is the property of Kerotest Manufacturing Corp. 5500 Second Avenue, Pittsburgh, PA 15207 and may not be
copied by any means without the expressed written consent of Kerotest. It is intended for the sole purpose of helping
Kerotest customers evaluate Kerotest products and may not be released to any third party or otherwise used in any
manner injurious to the interests of Kerotest
.
PRIMARY REPACKING PROCEDURE – EARLY DESIGN BEFORE (1988)
CONDITION 1 – VALVE UNDER PRESSURE
(REFER TO DRAWING ON PAGE 12)
1.
Open valve fully. Backseat to form a seal between lower thrust washer (12) and stem
shoulder (11).
2.
Remove nut (1), and operating square (2).
3.
Remove two of the cap screws (3). Replace with two all thread studs (size and length
recommended in table above). Thread all thread studs into cover until they bottom.
Install a nut on each stud and tighten. Remove all remaining cap screws (3).
4.
Slowly and evenly loosen the two nuts on the all thread studs, watching that the studs
do not unthread from cover as the nuts are turned. (If gland rises as the nuts are
loosened, backseat seal has not been obtained. Retighten nuts, replace and retighten
missing bolts, and then reattempt backseat seal.) Continue to loosen nuts until the top
of the nuts are flush with the top of the safety studs.
5.
Rotate stem slowly with open end wrench on stem square (10) until pressure pops
packing. Backseat immediately.
Caution:
Grip end of wrench and keep fingers clear. Pressure may slam gland against
wrench when packing pops.
6.
If packing does not pop out, replace gland, retighten nuts on all thread studs, and
replace and tighten remaining cap screws (3). Close valve tightly and turn to Secondary
Procedure for early design and continue with fourth step.
7.
Remove nuts and gland (4). Upper thrust washer (6) may remain in gland (4) or on
stem (10).
8.
Remove top packing adapter (7), v-rings (8), and lower packing adapter (9).
9.
Lubricate new parts with light oil and insert in packing chamber as follows: Lower
packing adapter (9), v-rings (8), and top packing adapter (7).
Note:
A slight leak in the backseat seal can cause difficulty in replacing the v-rings; a
straightened paper clip or smooth wire can be used on the side of the v-rings to allow
pressure to vent until the adapter can be quickly inserted and the gland bolted down.
