QM-Nr: FB_BMA_01-R-0804engl_3
Erstellt/
Prepared
: am/
on:19/11/2015
Genehmigt/
Approved: am
/
on19/11/2015
13 / 16
by ROFI S.A.R.L.
Attention !
Bolted connections must never be slackened on valves under pressure and only tightened
in case of emergency (e.g. leakage) in accordance with Accident Preventions Regulations (UVV),
permitted torque and under expert supervision using the proper tools
.
Spring loaded stuffing boxes must also be checked for tightness during operation, and tightened as
necessary (see point 4.1). It should be noted that the stuffing box must seal without a major increase of
friction at the spindle. We recommend that regular checks be carried out during operation.
6. Maintenance
Because of their hazard potential valves are comparable with other pressure vessels and as such are
governed by the relevant Accident Prevention Regulations (UVV). Before undertaking maintenance and
assembly work, make sure that the valve is not under pressure or temperature and that the system before
and after the valve is completely blocked of. Valves must be regularly serviced to ensure trouble free
operation. Typical maintenance points include checking glands, lubricating spindles, function checks. At
less frequent intervals valves should be closely inspected for wear and shut down to change lubricants
and gland packing. It is not feasible to recommend specific intervals owing to the wide variety of unknown
factors involved, such as the position of the valve within the plant configuration, the medium, operating
cycle, temperature change loadings and so forth. The user should call upon his experience as plant
operator to specify inspection and maintenance intervals.
6.1. Gland packing, Bonnet-flange-seals and Replacement
The gland seals the gap between body and spindles against loss of medium. The packing materials are
selected to suit the particular requirements - as far as known to us -and long life can normally be
anticipated. If packing does require replacement however, proceed as follows: The packing cavity must be
opened in accordance with the Accident Prevention Regulations (UVV) with the valve at ambient
temperature and not under pressure. The old packing must be removed completely before the new one is
fitted. The empty cavity and gland contact faces must be thoroughly cleaned. Ensure that the turndown
bolts on the gland ring are eased. If using slotted packing rings, the ring gaps must be offset by 120-180
degrees to one another. Once repacking is complete, operate the valve several times and if necessary the
gland bolts further tightened down (see point 4.1). The gland must be checked for tightness during
operation. If required it should be re-tightened since a leaking packing can be quickly destroyed by
erosion.
Attention !
It is not allowed to repack a valve when the valve is under pressure. Even when the valve
has a backseat device. Since the sealing effect of this back seat can be greatly reduced after a
short time of operation through dirt, wear or corrosion, however with an attendant hazard for
fitters when slacking off the gland screws
.