internally and externally and lined with 11 gage (3.04 mm0.1196 inch) 410
stainless steel plate where body comes in direct contact with coal.
Construct inlet skirt of not less than 6 mm 1/4 inch thick 410 stainless
steel with outlet body plates constructed of 10 mm 3/8 inch thick mild
steel lined with 11 gage (3.04 mm0.1196 inch) 410 stainless steel plate.
Construct water collecting trough of not less than 11 gage (3.04 mm0.1196
inch) 410 stainless steel plate and containing water sprays for flushing.
Valve body shall have dust-tight steel gate assembly cover with molded
gasket for removal of gate without removing the coal valve. Provide a
hinged access panel not less than [_____] by [_____] mm inches in the
direction of gate travel with compression-type latches over the water
collecting trough for removing obstructions.
2.9.16.2
Valve Gate
Slope gate plate toward water collecting trough and mount it on large ball
bearing rollers with 16 gage (1.52 mm0.0598 inch) stainless steel shells
equipped with felt grease seals and stainless steel grease retainers.
Provide rollers with grease fittings extended through the valve body for
pressure lubrication. Gate shall be U-shaped with ladder racks on both
sides and shall be constructed of not less than 16 mm 5/8 inch thick mild
steel lined with 11 gage (3.04 mm0.1196 inch) 410 stainless steel plate.
Gate design shall be such that supporting rollers, racks, and pinions are
located completely out of the coal stream. Racks shall be cold formed and
self-cleaning, with stainless steel, self cleaning pinions over racks.
2.9.16.3
Operating Shaft
Mount in ball bearings with felt seals, stainless steel shells, stainless
steel grease retainers, and grease fittings. Mount a reduction gear on the
gate shaft and provide an ample gate clearance pocket in the body to ensure
ease of operation through a standing column of coal. Handwheel for
operating the valve shall be not less than 457 mm 18 inches in diameter.
2.9.17
Chutes
Construct coal chutes dusttight as indicated of not less than 6 mm 1/4 inch
thick 410 stainless steel plate. Weld chutes with flanges located as
indicated to facilitate equipment and chute section removal.
Flanges
shall be not less than 10 mm 3/8 inch thick steel and gasketed to maintain
dust-tight seal. Poke holes and access panels shall be provided where
indicated.
2.9.18
Coal Presence Indicators and Equipment Response Switches
May be of the following types and shall be interlocked with the coal
handling controls to indicate equipment failures, coal stoppages, and
provide for a semi-automatic system. Enclosures for components shall meet
the requirements of NEMA Type 7, Class I, Division I, Groups C and D, and
NEMA Type 9, Class II, Division I, Groups E, F, and G.
2.9.18.1
Type A - Diaphragm Type Presence Indicator
Pressure-sensitive to presence of coal consisting of housing, diaphragm,
limit switches, wiring, and mounting bracket flanges. Housing shall be
either cast iron, stainless steel, or protected cast aluminum, with
synthetic diaphragm as recommended for coarse slightly abrasive materials.
Diaphragm deflection shall actuate a limit switch to indicate coal
presence. Design unit so that maintenance, diaphragm replacement and
SECTION 15502N
Page 114
Previous Page
