Fisher A41 Instruction Manual page 8

D Flange Studs: Install two or more line flange studs into the line flanges to help hold the valve in position while
centering the valve. Carefully center the valve on the flanges to ensure disc clearance.
D Select and install two pipeline gaskets.
D Flange Cap Screws: If line flange cap screws are used, be certain the cap screw threads engage the tapped holes to a
depth equal to the flange cap screw diameter.
4. Install the remaining line flange bolts to secure the valve in the pipeline. Tighten the bolts in a crisscross pattern to
ensure proper alignment of the valve with the flanges.
Packing Adjustment and Shaft Bonding
WARNING
Personal injury could result from packing leakage. Valve packing was tightened before shipment; however, the packing
might require some readjustment to meet specific service conditions.
CAUTION
Excessive tightening of packing will accelerate wear and could produce higher rotating friction loads on the valve stem.
1. For PTFE or graphite packing: Tighten standard packing follower nuts only enough to prevent shaft leakage.
Excessive tightening of packing will accelerate wear and could produce higher rotating friction loads on the valve
stem. If necessary, refer to the Packing Maintenance section.
2. ENVIRO-SEAL Packing Systems will not require this initial re-adjustment. Refer to the separate ENVIRO-SEAL Packing
System for Rotary Valves Instruction Manual (D101643X012) for repair and adjustment procedures.
3. For hazardous atmosphere or oxygen service valves, read the following Warning, and provide the bonding strap
assembly mentioned below if the valve is used in an explosive or hazardous atmosphere.
WARNING
The valve drive shaft is not necessarily grounded to the pipeline when installed. If the process fluid or the atmosphere
around the valve is flammable, personal injury or property damage could result from an explosion caused by a discharge of
static electricity from the valve components.
Standard PTFE packing is composed of a partially conductive carbon-filled PTFE female adaptor with PTFE V-ring packing.
Standard graphite packing is composed of all conductive graphite ribbon packing rings. Alternate shaft-to-valve body
bonding is available for hazardous service areas where you feel the the standard packing is not sufficient to bond the shaft
to the valve (see the following steps).
For oxygen service applications it is necessary to provide alternate shaft-to-valve body bonding (see the following steps).
4. Attach the bonding strap assembly (key 131, figure 5) to the shaft with the clamp (key 130, figure 5).
5. Connect the other end of the bonding strap assembly to the valve flange cap screws.
6. For more information, refer to the Packing Maintenance section below.
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