SVF FS7 Series Installation, Operation And Maintenace Manual Download Page 2

Page: 2 / 5

[email protected] • [email protected] • Visit our website: www.SVF.net • Specifications subject to change without notice

www

SVF

.net

Please visit www.SVF.net for the latest updates on this document. All data posted on our website supersedes all prior publications • [Document # SVF_FS7_IOM • 10/21/2013]

INSTALLATION, OPERATION & MAINTENANCE FOR SVF

SERIES FS7 BALL VALVES

FS7 Series Ball Valves

I N C O R P O R A T E D

Flow Controls

IOM-FS7

INSTALLATION
The valve may be installed for flow or vacuum in either
direction. Carefully exclude pipe sealants from the
valve cavity. When installing, use standard gaskets
suitable for the specific service. Tighten flange bolts
or studs evenly.

OPERATION
SVF valves provide tight shut off when used under
normal conditions and in accordance with SVF’s
published pressure/temperature chart. If these valves
are used in a partially open (throttled) position seat life
may be reduced.

SVF valves have ¼ turn operation closing in a clockwise
direction. It is possible to see when the valve is open
or closed by the position of the wrench handle. When
the wrench is in line with the pipeline, the valve is open

Any media which might solidify, crystallize or polymerize
should not be allowed to stand in the ball valve cavities
unless regular maintenance is provided. If minimal
maintenance is required, SVF offers steam jacketed
ball valves.

TORQUE REQUIREMENTS
Torque ratings are subject to variations depending on
the length of time between cycles and the media in
the system.

Breakaway torque is that force which must be exerted
to cause the ball to begin to open. Operating torque
requirements will vary depending on the length of time
between cycles, media in the system, line pressure
and type of valve seat.

MAINTENANCE
With self-wiping ball/seats, SVF valves have a long,
trouble free life, and maintenance is seldom required.
But, when necessary, valves may be refurbished, using
a small number of components, none of which require
machining.

SVF valves are designed for easy service and
assembly in the field. The following checks will help
to extend valve life, or reduce plant problems.

SVF ball valves utilize live-loaded stem seals featuring
Belleville washers (disk springs) that maintain constant
pressure on the Stem Seal area even under a wide
range of pressure and temperature fluctuations. If
stem leakage is evident proceed as follows:

STEM LEAKAGE
Examine the disk springs (Belleville washers) for
damage. If in good condition tighten the gland nut
until disk springs are firmly compressed, then back
nut off 1/16

of a turn. If damaged, dismantle the

stem down to the gland, fit new disk springs with
their outer edges touching, replace and retighten
using gland nut. Further maintenance necessitates
dismantling of the valve.

LEAKAGE AT BODY JOINT
Check for tightness at the body connector bolts.
If loose, tighten body bolts. Excessive force will
damage the bolts. (See Table A below)
If there is still leakage it will be necessary to dismantle
the valve and replace the body seals.

IN-LINE LEAKAGE
Check that the valve is fully closed. If leakage occurs
while the valve is in the closed position, a seat or
ball sealant surface may be damaged and it will
be necessary to disassemble the valve.

NOTE: If Stem leakage and leakage at body joint are
not cured by the simple means described above,
it will be necessary to dismantle the valve. If there is
no stem leakage the stem assembly should not be
touched.