valve opening time taking more than required

hi 

can anyone help me,

valve operating pressure minimum is 58 psi, and normally the valve air fail position is close.

so when i am giving the pressure @ 58 psi, the valves start to open, but it is taking more time to open. it is taking 28 second to open against 18 second,

so what to do so that the valve should open completely within 18 seconds,

please help

  • Hello , great question - I have taken the liberty of moving your inquiry to the valves group where I believe it you will get a quicker response.

    Best Regards,

    Rachelle McWright: Business Development Manager, Dynamic Simulation: U.S. Gulf Coast

  • Hi Wazid. What is the model of the positioner and the model and size of the actuator? Is this a new problem?
  • In reply to MOH:

    Hi Wazid. John is correct at starting at what you have. If you currently have a volume booster between the positioner and the actuator then it may need adjustment to the bypass setting. The booster will improve speed of response performance, knowing the positioner and actuator size will enable a decision about the flow capacity of the volume booster to use. There are several sizes available to meet performance requirements.

    Kurtis Jensen  |  Instruments Product Manager | Fisher

    T (+1) 641 754-2511  |  Mobile: (+1) 641 485-1805

    kurtis.jensen@emerson.com

     

  • In reply to kkjens:

    Dear Sir, the type of valve is ON/OFF valve type, and its size is 6 inch. and we are using solenoid valve to operate, and there is no any volume booster or positioner.
  • In reply to John Brinson:

    Dear John
    There is no positioner at the valve, and the model of the actuator is CBA930-SR60-CW and the size of the actuator is 6".
  • In reply to Wazid Hasan:

    Hi Hasan
    i think, this is due to low flow rate, you can check flow rate of regulator, solenoid, and tubing size.
  • You need to check the tubing size and the Cv of the solenoid valve   I suspect that you need to increase both or increase the air pressure available to the actuator.  You should also check the torque requirement for the valve and make sure that the actuator is sized correctly for your supply air pressure

  • Wazid,
    Can you please provide the SOV model & AFR model in order to check the flowrate.
  • Hello.
    For CBA930-SR60-CW air stroke to open in 18 sec, you will require a total system Cv above 0.4 (that is all controls accessories in the supply line) and air supply source flow rate above 7 SCFM.
  • In reply to Rajeev Sivam:

    Hi Sir,
    The model no of SOV is "WSNFET 8327B102 24/DC and the S.No of AFR is DRN0714-0533
  • In reply to Wazid Hasan:

    Wazid, This solenoid is 0.56 Cv to pressurize the actuator and 0.49 Cv to exhaust. I recommend that you go to the higher flow solenoid, WSNFET8316A381 24/DC. This solenoid has a Cv of 1.5. This will help with your opening and closing response times.

    Bill Reeson

    Global Project Pursuit & Strategic Account Manager | ASCO

    Emerson

    T +1 973 966 2097 | M +1 973 495 8561

    Bill.Reeson@Emerson.com

  • In reply to Bill Reeson:

    I agree with Bill to increase flow capacity of solenoid.

    Kurtis Jensen  |  Instruments Product Manager | Fisher

    T (+1) 641 754-2511  |  Mobile: (+1) 641 485-1805

    kurtis.jensen@emerson.com