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Tapco Slid Valve

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This topic contains 12 replies, has 2 voices, and was last updated by  Anonymous 10 years, 8 months ago.

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  • #3621


    Gents, I want to learn more from your valuable experience in this field, so what is the required routine maintenance for FCC slide valves (hydraulic unit) during normal operation and what is shutdown maintenance requirement for the slide valve system. Also from your experience what are the most expected problems from these valves during normal operation. Thanks………….

  • #6832


    There are several questions that must be answered before a complete and pertinent answer can be given to this question. Drop me a line at and we can get your question answered.

  • #6177


    During nrml operations you may expect
    1.   Guide purge may turnoff due to catalyst choking,
    2.   When there is a loss of signal to DCS, you may have to take it on handwheel
    3.   Catalyst may leak through the stem.
    and so on… these are some which we have faced.

  • #6155


    have you operators cycle the valve +/-3% remote while one is local to verify response…. atleast weekly.  as previously mentioned, verify your purges are properly in services


  • #6077

    Walter Stinson

    There are operational problems that could occur because of the slide valve itself OR there could be operational problems that could be caused by the Electro-Hydraulic Control System and Valve Actuator. If you have some specific concerns you may contact me at

  • #5990


    Past issues with Slide valves (FCCU) Unit

    • Hydraulic Oil –  Low Level, High/Low Temp (Cold Weather) Hydraulic Fluid type
    • Main Filter pluggage,and with a servo valve,  it malfunctioned due to a built in filter problem, Valve started moving on its own
    • Valve deviation alarm (Stuck)  from SP due to Catalyst build up on Valve guides, operation now purge blast and Stroke off line Valve one per shift, constant purge on all guides and body, or pump problem unable to move valve
    • Small PSV on Hydraulics releasing , set to low or just failed


  • #5989


    Dear Guest,
    There are a lot of questions that need to be asked to better define specific answers.
    However, note the following general comments:
    a) Please clarify comments on Hyd-Fluid
    Level Level can be from leak or loss of Nitrogen pre-charge gas in accumulators.
    High & Low Fluid Temp ???
    Fluid Type – Specify Mfg and fluid designation
    b) Filter problems ?  Have you done fluid analysis to determine cleanliness? I can send you Fluid Filtration Handbook.
    c) Deviation alarm – How have you determined sticking was from slide valve and not lack of actuator thrust?
    d) Note that excess purging can cause excess internal erosion and valve damage. Do you have maintenance record from last overhaul that would show clearances set for valve internals?
    e) Were pump problems from worn pump or was problem loss of pressure caused by PSV?
    Are these problems resolved?   Do you know valve design type?
    You may contact me directly @

  • #5734


    I can send you a procedure for them I wrote, if you need one. Whats your email?

  • #5524


    Could you send me the procedure on my email SRINIVAS997@GMAIL.COM?

    Thanks in advance.

    Srinivasa Rao Pinnam.

  • #5500


    while commissioning we have observed that LVDT not responding ie giving a constant output even though valve is changing position.

  • #5499


    Answer may depend on type of Feedback. However, note that if you have a Tapco system with MTS feedback transducer the problem may be the servo valve amplifier. You note valve is still “changing position” so I would assume it is still controlling on auto control.
    If this is the case it would mean the LDT (Linear Displacement Transducer) is still functioning and allowing auto/servo control. The servo amplifier circuit board can still control the closed-loop circuit after its output signal (signal back to control room) is lost.

    This circuit board output is a typical control component and can be caused to fail by things like a lightning strike.
    Does this look like the failure you have found? Do you have continued control but no position signal back to the control room?

    Slide-Valve Wally
    Stinson Valve-Actuation LLC

  • #4678


    We use Bafco slide valves out of Pennsylvania and have rarely had issues. We use this hydraulic system for both slide valves, our regen/Rx differential valve, expander bypass valve, CO boiler inlet and bypass valves. Mechanically, these valves are superior. We go 4-5 years between maintenance on them, including hydraulic fluid filter change out. I highly recommend them to anyone having issues with their hydraulic valve systems.

  • #4677


    Just a note: Bafco does make a reliable hydraulic actuator and control system. Don’t get this confused with the manufacturers of the slide valves and butterfly valves as Bafco does not make valves. You do make a valid point of reference in that a clean hydraulic system is normally a reliable system whether it’s a Bafco, Tapco, BLAC or MEA system.

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