4 Valve Description
16 of 72
0570.81/22-EN
Variants
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Stem protecting tube
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Stem protecting tube with position indicator (≥ DN 250)
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Stem protecting tube with position switch (≥ DN 250)
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Position switch(es) mounted on yoke (≤ DN 200)
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Bypass
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Drain branch
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Barrier water connection
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Electric actuators
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Bevel gear and spur gear (recommended from ≥ DN 700)
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Installation kit for actuators and manual gearboxes
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Seat/disc interface made of wear-resistant and corrosion-proof Stellite
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Stem made of 1.4122
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TA-Luft-compliant model (with or without spring loading) for applications to
VDI 2440 at temperatures ≤ 250 °C and > 250 °C (400 °C maximum)
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Other flange designs or butt weld end designs
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Inspections to technical codes such as TRD/TRB/AD2000 – German Steam Boiler /
Pressure Vessel Regulations – or to customer specification
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≥ DN 900 on request
4.3.1.3 Function
Design
The gate valve comprises the pressure-retaining parts, i.e. body 100 and yoke 166, the
functional unit (stem 200, wedge/disc holder 367 and flexibly mounted wedge discs
360), and the actuating element.
Function
The valve is actuated using a handwheel, manual gearbox or electric actuator.
Sealing
Body 100 and yoke 166 are connected by studs 902.1 or grub screws 904 and nuts
920.1, and the joint is sealed to atmosphere by joint ring 411.1.
The seating faces of body 100 and wedge discs 360 are hard-faced. Gland packing
461, which seals off stem 200, is tightened via gland follower 452 by means of studs
902.3 or hinged bolts and nuts 920.2.
