Flanged and clip closure connection and adjust the flow with the flue butterfly valves are available in nominal pressure ≤PN0.6MPa, nominal diameter ≤DN3000mm, temperature ≤450 ℃, the medium is air, flue gas dust and gas and other industries.
Flue butterfly valve is suitable for adjusting the flow rate within the specified range and the closure.Flue butterfly valve compared with metal seal butterfly valve, butterfly valve in the conditions of use, structure and technical requirements, and leak rate test and test methods are different.
Metal seal butterfly valve minimum standard E-class gas maximum allowable leak rate: 200 × DN (mm3 / s).
Butterfly valve highest standards of A-level flue gas maximum allowable leak rate: L 0 = K × DN2 × √P × 10-6
Where L 0 — maximum allowable leakage rate, Nm3 / h.
K — A level leak factor
DN — butterfly valve nominal diameter, mm
P — test pressure, MPa.
From the above analysis standards and formulas, flue butterfly valve A level leak rate significantly higher than standard metal seal butterfly valve leak rate E-class standards. In the butterfly valve DN1200 caliber, for example, metal seal butterfly E-class standard maximum allowable leak rate
200 × DN = 200 × 1200
= 240 000mm 2 / s
= 0.014 4m3 / min
A level standard flue butterfly maximum allowable leak rate (according to 0.6MPa Nominal)
L0 = K × DN2 × √P × 10- 6
= 7.3 × 12002 × √600 000 × 10 – 6
= 8143Nm3 / h
= 136Nm3 / min
Analysis by the formula, flue butterfly valve and metal seal butterfly valve on the structural design and test methods are different, the flue butterfly valve sealing requirements significantly lower metal seal butterfly valve, its regulation characteristics similar to metal seal butterfly valve.
What are the technical requirements of the flue gas butterfly valves?
Flue gas butterfly valve flange dimensions, the sealing surface in the form of both ends of the flange bolt holes d0 axis with respect to the flange of the position tolerance, the minimum length of the structure and the valve seat diameter bore axis is to follow certain standards and technical requirements.
Flue gas butterfly valve flange dimensions and sealing surface in the form of regulations according to API609, and flue gas butterfly valve flange sealing surface should be perpendicular to the channel axis, coaxial with the axis should smoke butterfly valve channel, flange sealing surface should be parallel to each other at both ends of its axis its parallelism by API609 accuracy, connecting flange structure according to the need to allow the bolt hole threaded flange bolt holes at both ends of the axis relative to the flange d0 position tolerance bore axis as defined, the flange connecting flue gas butterfly valve structural length required to API609, and to connect the flue gas butterfly valve clip length of the structure in accordance with the provisions of API609, the nominal diameter of 2000 mm greater than the length of the flue gas butterfly valve structure according to user requirements to determine the seat of the minimum diameter It shall not be less than the specified.
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