Installation, Operation & Maintenance Manual
26
Top-Transfer 2" Angle Valves A-720, A-721, A-721-B and A-724 Series
NOTICE
NOTICE
CAUTION
NOTICE:
It is essential to establish a periodic retesting and preventative maintenance program with angle valves.
The DOT and AAR have set forth a retesting interval that should be considered the maximum length of time
between tests. If your company’s experience indicates that a short interval is advisable, a program with more
frequent retesting should be implemented.
NOTICE:
New O-rings should be installed when a valve is retested.
NOTICE:
It is the responsibility of the car owner to develop a maintenance and qualification program that
ensures the valve and fittings meet the performance specifications. Midland’s guidelines are meant to assist in the
development of the maintenance and qualification program.
NOTICE:
Midland identifies the replacement of the face plate or outlet flange, on a Midland angle valve, not to be
a part of the Resealing, Rebuild or Remanufacturing of the valve or fitting. The face plate or outlet flange may be
changed as a regular part of maintenance, without the removal from the railcar. All proper assembly techniques,
torque specification as well as leak testing are required to be performed to ensure the proper performance
requirements are met.
CAUTION
:
The repair procedure for a mounted valve is intended only as a temporary repair. Once a product is
unloaded and pressure is relieved. The valve should be removed for further repairs and full requalification.
8 MAINTENANCE
8.1 PRIOR TO MAINTENANCE TASKS PERFORMED
8.1.1
Required Tools
8.1.1.1
Obtain the required tools and supplies before attempting maintenance procedures. Table 1-3 outlines some suggested tools
that will be needed.
8.2 LEAK REPAIR ON A MOUNTED VALVE
8.2.1
Inspect the valve for leaks according to your company’s procedures for this testing. To repair packing gland area leak, loosen
the packing lock nut, then wrench the packing screw down slowly until the leak stops. Then turn another 1/4-turn and lower
the locknut on the packing screw.
