UNITED 3900F Series, Инструкция по установке и обслуживанию

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INSTALLATION
It is strongly recommended that instruction manuals supplied by the valve manufacturer be reviewed in detail before installing
butterfl y valves.
1. Handle valves carefully when positioning, avoiding contact or impact with other equipment, vault walls or trench walls.
2. Valves are to be installed in accordance with the manufacturer’s instructions.
3. Where practical, valves in buried installations should be located in unpaved areas, unless otherwise indicated in plans and
specifi cations.
4. Foreign material in a butterfl y valve can damage the rubber seat when the valve is operated. Be sure valve interiors and
adjacent piping are clean and free of foreign material when making a valve-to-pipe-joint connection.
5. Prepare pipe ends and install valves in accordance with the pipe manufacturer’s instructions for the joint used. Do not use a
valve as a jack to pull pipe into alignment. The installation procedure should minimize the bending of the valve/pipe connection
with pipe loading.
6. Concentrically center the valve disc between the mating fl anges.
7. Make sure the valve disc, when opened, will not contact the pipe port. This is especially necessary on pipe with linings and
when wafer valves are used. Check manufacturer’s recommendations for minimum pipe inside diameter require for clearance.
8. Buried valves installed with valve boxes shall be installed so that the valve box does not transmit shock or stress to the
valve actuator as a result of shifting soil or traffi c load.
9. When valves are installed in vaults, the vault design shall provide space for removal of the valve-actuator assembly for
purposes of repair. The possibility of groundwater or surface water entering the valve and the disposal of the water should be
considered. The valve operating nut should be accessible from the top opening of the vault with the tee wrench.
TESTING
When rubber-seated butterfl y valves are used to isolate sections of a line for testing, it is important to realize that these valves
are designed or factory adjusted to hold rated pressure only. Test pressures above valve rated pressure may cause leakage
past the rubber seat and damage to the valve.
1. In order to prevent time lost searching for leaks, where feasible, it is recommended that excavations for buried valves not be
backfi lled until after pressure tests have been made.
2. Seat leakage can occur from foreign material in the line. If this occurs, open the valve 5°-10° to obtain high-velocity fl ushing
action, then close. Repeat several times to clear seats for tight shutoff .
3. Seat leakage can result from a rotational shift in the position of the disc with relation to the body seat. Readjust the closing
stop in the valve actuator assembly.
RECORDS
On completion of installation, the valve location, size make, type, date of installation, number of turns to open, direction of
opening, and any other information deemed pertinent should be entered on the owner’s permanent records.