Jafar 4499 Посібник з експлуатації та технічного обслуговування - Сторінка 4
Переглянути онлайн або завантажити pdf Посібник з експлуатації та технічного обслуговування для Блок управління Jafar 4499. Jafar 4499 10 сторінок. Return butterfly valves double eccentric
Друкувати сторінкуVersion marking
I – horizontal pipeline,
II – vertical pipeline, bottom-up flow,
III – vertical pipeline, top-down flow.
Lever position from the perspective from the flow direction:
R – right,
L – left.
Due to the difficulty in achieving the tightness within the scope of 0-1.6 MPa, as is required certain pressure
against the flap while closing and opening, two scopes of the closing tightness are determined:
W – 0.3-1.6 MPa,
N – 0.03-0.6 MPa.
Minimum opening pressure
Marking example:
return butterfly valve 4499 DN300 for installation II, for operation within the scope of low pressures,
return butterfly valve of cat. no. 4499 DN300-II-L-N.
Operation requirements:
Avoid the installation of butterfly valves near bends, T-pieces and curvatures.
In order to reduce the hydrodynamic effect (impact), it is recommended locating the butterfly valve at the
distance of 5xDN (i.e. distance of the flange from the curvature).
Avoid installing in diagonal pipelines.
In case of projected or existing hydraulic impacts or turbulence, use butterfly valves for the nominal pressure
higher by one degree, e.g. PN -2.5 MPa or decrease pressure Prob-1.0 MPa.
The safe hydraulic impact load is to be found in Table 2.
Table 2
Dnom
Hydraulic load-Mg
(for PN16)
A properly mounted butterfly valve should work automatically. Check whether the manually lifted (to
the flow-through position) lever with a disc returns after being released without resistance to the closed position.
Perform a trial without pressure nor flow.
Disturbances in the return butterfly valve's operation can be divided into:
closing leakiness,
casing leakiness,
excessive opening pressure,
noisy operation (impacts).
As for the closing leakiness, check whether the mounted butterfly valve is intended for such a pressure
scope as at pt. 4. If so, the seal could have been broken (item 5). It should then be replaced by loosening the bolts
and removing the cap (item 3).
As for the casing leakiness:
leakage from underneath the cap (item 3): as above, replace the seal (item 5).
leakage on the lever pivot (item 4) side: knock out the lever pin by removing the lever and supporting
weight, remove the cover, replace the sealing rings (o-rings),
leakage on the rear cover side: replace the o-ring sealing.
too high an opening pressure or noisy operation: high friction resistance at pivots in the bearing: remove
by the proper positioning of the supporting weight at the lever. Loosen the bolt and position the weight
properly, then tighten the bolt locking the weight.
≥
0.03 MPa.
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