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HANDWHEEL
The spoked handwheel is fabricated from steel pipe. The hub is
coupled with the yoke sleeve by means of a tongue.
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YOKE SLEEVE
The yoke sleeve is made from cast aluminium bronze having high
resistance to wear and a high melting point. It is designed to
permit removal from the bonnet or the yoke whilst the valve is
in service. Gate valves 6" class 600 and above are fitted
ball thrust bearings.
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GLAND
AND FLANGE
They are in forged steel and are supplied in two pieces, self
aligning design to permit the gland to descend parallel to the stem
even if the eyebolts are unevenly tightened.
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GLAND
BOLTS AND NUTS
The forged steel gland bolts are of the eyebolt type which can
be swung outward for ease of gland repacking. They are fixed
to the bonnet by hinge pins.
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 BONNET
BOLTING
Bonnet studs and nuts are manufactured from alloy steel to the
relevant ASTM standard.
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BODY The body
is in cast steel and is carefully designed in all its details. The
basic dimension, i.e. wall thickness, face to face and flanges
comply with the relevant API and ANSI standards. The body-to-bonnet
flange is circular, expect in the Class 150 which is oval. The
body-to-bonnet joint are flat face on Class 150 valves,
male-and-female on Class 300 and ring joint on Class 400 and above.
The body is threaded for renewable seats. Bosses are provided for
drain taps or by-pass piping.
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 BONNET
The bonnet is in cast steel. It is machined to accept yoke sleeve
and incorporates a stuffing box dimensioned in accordance with the
API standard.
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 BONNET
BUSHING
The bonnet bushing or backseats is in forged stainless and forms
part of the trim. Special attention is given to its machining.
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STEM
The stem is in
forged stainless steel and is part of the trim. The stem is provided
with a T head. A ground backseat is provided to ensure a perfectly
tight seal to the stuffing box when the valve is fully open. The
stem is ground to minimize friction and prevent damage to gland
packing. The threading is trapezoidal ACME type. Dimensions comply
with the API 600 standard.
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 SEAT
RINGS The
rings are in forged stainless and are part of the trim. They are
completely threaded outsider and notched on their inner surface to
ease installing and dismantling. Special attention is given to the
sealing surface which are ground and lapped for a perfectly seal.
Welded-in-seat rings may be supplied upon request.
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WEDGE
The wedge is part of the trim. It is forged stainless steel for
diameters up to 12" and is in cast steel for larger valves. It
is normally supplied as the solid wedge type. It is connected to the
stem by means of a T joint. The guides on each side of the wedge are
machined. Special attention is given to the seating surfaces which
are ground and lapped.
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REMARKS:
A lantern ring is furnished only on request, in this case the
stuffing box shall be tapped and fitted with an NPS 1/4 plug.
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