Masoneilan 39003 Series, Инструкция по эксплуатации

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Instructions EM39003 - 05/10
39003 Series High Performance butterfly Valves
5
1.7 Operating Pressures
All Masoneilan HPbVs may be applied to full AnSI ratings.
However, different materials of construction may affect the
rated pressure. The shut-off pressure rating is determined by
the valve shaft and disc materials as well as the seat design,
and is reflected on the metal identification tag attached to the
valve.
1.8 Seat Alternatives
Masoneilan HPbVs have three alternatives, all of which are
bi-directional.
Soft Seats
provide tight shut-off to zero leakage specifications.
Standard Soft Seat material includes virgin TFE or reinforced
TFE (RTFE).
Fire-Safe Seats are designed for critical piping applications
in installations such as Refinery and Petrochemical Plants.
These seats are a combination of both metal and soft seats
with the metal seat being designed to function during and after
a fire. Valves of this type are referred to as “Fire-Safe” and are
tested to meet API 607 “Fire-Safe” specifications and operation
criteria.
Metal Seats are well suited for higher temperature applications
and provide shut-off to AnSI b16.104 Class IV.
1.9 Offset Disc Design
All Masoneilan HPbVs have both off-set discs and eccentric
shafts. The off-set is applicable to the disc edge seating surface
relative to the shaft center line. by off-setting the seating
surface from the rotational center line, a contact with the seat
is possible throughout the 360° circumference. The shaft is
eccentric in the body by 0.060 inches and this enhances seat
life by imparting a camming action to the disc as it rotates both
in and out of the seat. Seat wear points are eliminated at the
top and bottom of the disc and operating torque is reduced.
Soft Seat
Profile
Fire-Safe
Seat Profile
Metal Seat
Profile
Figure 3
Figure 4
Figure 5
Figure 6