EMERSON Manuals Hardseat Blow-Off Valves, Yarway-EN

YARWAY HARDSEAT BLOW-OFF v ALv ES INTEGRAL YOKE DESIGN

How to operate and service hardseat blow-off valves (integral yoke design).

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Hot discharge from this device can cause severe Seat and disc design, with stellite sealing burns. Discharge must be piped or directed away surfaces. Beveled end of steel disc has so no one will be endangered. This device must welded- in stellite facing and inlet and outlet be insolated, vented and cool to the touch before nozzles have integral welded in stellite seats. repairing or inspecting.

This stellite provides smooth hard-wearing surfaces at these important points. Lip on end disc checks wire drawing and protects bearing faces against cutting action of blow-down.

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valve is usually installed with flow entering below seat. The valve should be opened rapidly and fully, to increase life of working parts; never blow down with valve partly open. note When installed in tandem combination, the Yarway hardseat blow-off valve, angle body, welded hardseat blowing valve nearest to boiler will ends. Operating and servicing instructions identical for have flow entering below seat. This blowing angle and straightway hardseat valve. valve should be opened last, closed first; the sealing valve, farthest from boiler, should be c ARe of h ARdse At v Alves opened first, closed last. Both valves should be opened rapidly and fully to increase life of lubrication working parts; never blow down with valves Keep hardseat valves well lubricated. partly open. Proper lubrication is extremely important.

Oil stem threads frequently. Yarway Sv- 650 (or equivalent) superheat mineral oil is recommended for these points.

cleaning or clearing All internal parts of the Hardseat valve can be removed without disconnecting the body from the line. If inside of valve must be cleaned or if a foreign body lodged in the valve prevents seating of the disc, disassemble as follows: 1. Loosen the two gland nuts and remove split gland bushing. 2. Turn handwheel past full open position to jack the packing and stuffing box bushing out of the stuffing box. 3. Break tack weld on yoke bushing and back out this bushing. 4. Remove internal parts through top of yoke. When valve is reassembled, yoke bushing note must be tack welded in place to prevent Yarway hardseat blow-off valve, straightway body, accidental loosening of the bushing while welding ends, in closed position valve is in service. It is also advisable to be sure to keep disc clear of seat during reassembly of yoke bushing.

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