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  • Users: shobi
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  1. shobi

    Centrifuge Instrumentation

    Thank you jmw, you finally got my drift. We have a 25 years old centrifuge process (26 birds all together in parallel configuration). They are used to centrifuge raw bitumen (oil sand industry) to remove solids (5 to 10% fines). Right now we don't have any kind of instrumentation on the process...
  2. shobi

    Failure Rate Data for 61508 / 61511

    I think your best bet would be to ask your manufacturer. For most of their product Emerson (Rosemount) have a 3rd party evaluation on their website.
  3. shobi

    Orifice Flange Tap Location For Steam Measurement

    When dealing with steam application it is important to protect the transmitter from possible over temperature conditions. The best way to do this is to take the impulse piping out the side of the process piping into the outlet of a Tee. Another steam transmitter installation I did in the past...
  4. shobi

    Steam Flash Drum Level Control Valve

    By the sound of it, I think the problem is the dowstream piping has a long run and in upward direction. This will cause your valve to cavitate because of downstream pressure build up caused by high mixed phase velocity. Of course it does not help when the size of the valve is less than 1/2 of...
  5. shobi

    Process Signal Wiring Standard

    Please refer to NFPA 79 or look for article 725 in NEC book.
  6. shobi

    I need comprehensive text about controll system

    I would recommend, Liptak (Process Control), Fundamentals of Industrial Controls, Continuous process control, and understanding distributed process system for control. These are good reference books and are available from ISA.
  7. shobi

    Orifice Flange Tap Location For Steam Measurement

    Steam DP transmitter tubing should slope downwards toward the DP cell and include a "dead leg" or pigtail.If either the condensate levels or both legs of DP cell can not be kept at the same height, the difference in elevation (levels or diaphragms) will cause a DP offset that must be compensated...
  8. shobi

    FLOW ELEMENT AND CONTROL VALVE

    As a general rule "control valves and abrupt enlargements must be installed an adequate distance downstream of the flowmeter to minimize downstream pipe effect"
  9. shobi

    Centrifuge process instrumentation

    Hello everyone, I am interested in instrumentation used to automate these type of centrifuges, especially in mining industry. If you have any first hand experience with them please write back. I am particularly interested in Bird's centrifuges. I have found very little information on their...
  10. shobi

    Centrifuge Instrumentation

    Hello everyone, I am interested in instrumentation used to automate these type of centrifuges, especially in mining industry. If you have any first hand experience with them please write back. I am particularly interested in Bird's (manufacturer) centrifuges. I have found very little information...
  11. shobi

    Scroll Type Centrifuges

    I am interested in instrumentation used to automate these type of centrifuges, especially in mining industry. If you have any first hand experience with them please write back. I am particularly interested in Bird's centrifuges. I have found very little information on their actual design and...
  12. shobi

    What Letters Shell I use for Gas and Flame Detectors?

    "BE" or "BA" stand for Burner Element and Burner alarms respectively. At our plant we use "BSE" for burner safety element or BE, BI or BM for Burner elemnt, Burner indicator or Burner Scanner. All the gas detectors and alarms are designated as AIT or ASH etc for analyzers. Thanks
  13. shobi

    Mechanical Needs Instrumentation Advice

    The only way I know to do it is via Hart Modem, available from emmerson (rosemount), and AMS (asset management suit) software. I don't know if Hart modem can work stand alone or you need complete package. Ask your nearest sales rep. The demo version of this package will cost approx. 1500 - 2000...
  14. shobi

    Control valves used as trips?

    SAFCON It's Your Call A control valve can be used in lieu of a separate safety shutdown valve for SIS applications. One technique is to install a solenoid in series with the valve positioner, downstream of the positioner output. The solenoid valve is operated by a SIS signal when a process...
  15. shobi

    Control valves used as trips?

    ISA-S84.01 section 7.4.3.1 specifically prohibits the use of a control valve from the basic process control system (BPCS) as the only final element for SIL 3. It goes on to say, "A safety review shall be required to use a single BPCS control valve as the only final element for SIL 1 and...
  16. shobi

    Control valves for oxygen service

    The primary concern with process valving in oxygen service is related to the propensity of pure oxygen to ignite whether incompatible material, unfavorable process conditions, or unanticipated events are introduced to the process. Among the acceptable materials of construction for valves used...
  17. shobi

    Pump safeties

    Beside usual safety instrumentation I would also consider an Automatic Recirculation Valve. This valve protects centrifugal pumps from damages that may occur during low-flow operations. Minimum flow protection is accomplished with an automatic, modulating bypass that assures smooth pump...
  18. shobi

    Measurement flow

    There are few options available. One old fashion way is to use a by-pass around the meter, so you can service/inspect your meter without interrupting the process. The other option is to buy an integral coupling (from rosemount). Rosemount also has a newer model 3051S which enables you direct...
  19. shobi

    Inherent Control Valve Characteristics

    Igor, Here is the guideline. First, check your process and find out what the "delta P" across the valve is at the minimum required flow rate and what the "delta P" is at the maximum flow rate. Establish a ratio between the two. If the ratio is less than 2:1, choose a linear...
  20. shobi

    Acceptance Forms

    I am in a process to develop acceptance forms for instrument source inspection, and installed instruments. Can some one guide me in the right direction please.

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