Ring piston replacement for EHT valve

Hi

I want to replace Ring Piston P/N:1U5069x0012, for EHT valve. i check the documentation but i can not find any procedure for replacing ring. would you please help me?

Thanks in advance

Youri

  • MOH,

    As per page 19 of the EHT instruction manual for NPS 1 1/2x1 through NPS 8x6, “Constructions other than TSO trim
    1. To install the piston rings and seal rings (keys 8 and 30), proceed as appropriate:
    For an EHD valve (figure 18), if it is necessary to install new piston rings, the replacement piston rings will arrive in one piece. Use a vise with smooth or taped jaws to break a replacement piston ring into halves. Place the new ring in the vise so that the jaws compress the ring into an oval. Compress the ring slowly until the ring snaps on both sides. If one side snaps first, do not try to tear or cut the other side. Instead, keep compressing until the other side snaps. The piston ring can also be fractured by scoring and snapping over a hard surface such as a table edge. Sawing or cutting is not recommended,”. ( www.emerson.com/.../instruction-manual-fisher-ehd-ehs-eht-valves-nps-1-1-2x1-through-nps-8x6-en-134942.pdf )

    For EHT NPS 8 through NPS 14 page 14, “For an EHD valve, if installing a new piston ring, the replacement piston ring will arrive in one piece. Use a vise with smooth or taped jaws to break this replacement piston ring into halves. Place the new ring in the vise so that the jaws compress the ring into an oval. Slowly compress the ring until the ring snaps on both sides. If one side snaps first, do not try to tear or cut the other side. Instead, keep compressing until the other side snaps.
    Remove any protective tape or covering from the valve plug and stem assembly, and set it on a protective surface. Then place the piston ring in the piston ring groove with the fractured ends matched.
    For an EHT valve, install the seal ring (key 8) onto the valve plug (key 3). Install the ring with the open side facing the seat ring end of the valve plug for a flow‐down application (view B of figure 14) or with the open side facing the valve stem end of the valve plug for a flow‐up application. Slide the backup ring (key 9) onto the valve plug. Secure with the retaining ring (key 10). For an EHT valve with a Whisper Trim Level D cage, install the piston ring (key 30, figure 14) using the procedure given in the EHD instructions immediately preceding this paragraph.”. ( www.emerson.com/.../instruction-manual-fisher-ehd-eht-nps-8-through-14-sliding-stem-control-valves-en-125064.pdf )

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    Richie

    Richard L Ritter III, PMP, MBA | Technology Specialist - Reliability Services | Final Control

    Emerson Automation Solutions

    Richard.Ritter@Emerson.com