Installation, Operation & Maintenance Manual
10
Top-Transfer 2" Angle Valves A-720, A-721, A-721-B and A-724 Series
4 OPERATING PROCEDURE
4.1 OPENING THE VALVE
NOTICE:
Operation of the valve must conform with all applicable CTC, AAR, DOT specifications
(Parts 173.31, 174.67, etc.), other governmental bodies, and the operating instructions of your company.
NOTICE
4.1.1
Wrench-tighten the nuts a little bit at a time, going alternately in a crisscross pattern, from 1 to 3, then 2 to 4. Do not tighten
down too much on one side because this will shift the valve at an angle and may make it impossible to get a tight gasket seal.
CAUTION:
Do not use an extension or cheater on the valve handle. If it does not move freely, report this to
the tank car supervisor. The tank may be pressurized, contain solidified product, or the valve may be jammed.
4.1.2
Examine the pipe plug. Be sure its threads are clean, free from corrosion, not worn or crossed. Also, examine the threads
on the side port to see that they are in good operating condition.
4.1.3
This valve has an adjustable packing gland. Routine maintenance consists of periodic inspection and adjustment of the packing
nut (item 8) to compensate for the stem seal wear. This may be done by loosening the gold locknut (item 21) and tighten the
packing screw to 65 ft-lb using a 1-1/16” wrench. More frequent observations are recommended under extreme operating
conditions. Unnecessary overtightening will cause excessive frictional drag on the valve stem. Then torque the locknut (Item 21)
to 65 ft-lb in order to keep the packing screw from unwinding during operations.
CAUTION
Plug
Figure 4-1 Plug and Packing Locknut
Packing Locknut
