All components of the Swiveldisc Gate Valve are shown and named in Figure A.

Routine Maintenance
Routine maintenance consists of a periodic tightening of the gland to prevent packing leakage. No other routine maintenance is required.

Adding a Ring of Packing Under Pressure
 When, after repeated adjustment, the gland has bottomed on the chamber shoulder, it is possible to add packing rings without removing the valve from service. Use the following procedure:

1. If possible isolate the valve and allow pressure to bleed off.
2. Open the valve fully and torque onto backseat. (See Table 2 for allowable torque).
   When the valve is pressurized the valve backseat provides pressure enhanced positive sealing. This does not provide the two valve protection which some saftey standards call for, proceed only as a last resort.
3. Check to see that leakage has stopped.
   CAUTION!  If leakage persists do not proceed without isolating the valve from system pressure.
4. Remove the handwheel to prevent loss of backseat seal due to accidental movement of the stem.
5. Unscrew the gland to full open height on the yoke bushing.
6. Open ring at split for insertion around the stem. (For steam service, Garlock 98 carbon filament packing is recommended.)
7. Slide ring into the chamber and compress it by tightening down the gland. Do not add more than one packing ring at a time. Rotate the rings so that splits are 90° apart Do not add more rings than can be accomodated by the straight bore portion of the chamber I.D. (See Table 2 for allowable gland torque.)
8. Reassemble handwheel and rotate the handwheel several times in both directions to "seat" packing. Tighten gland again, if necessary, to complete the seal. (NOTE: The stems are rising, nonrotating type and do not turn.)