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  • Users: omby
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  1. omby

    HART communicators

    Cheers for that danw2. I'll look into the Meriams... Agree with disposable batteries, it makes life easier, and have had minimal experience of Pactware which seemed - as you state - a lot of effort to interrogate transmitters not previously saved.
  2. omby

    HART communicators

    Have you had experience with this model danw2? I was after something fairly basic and more at the cheaper end of the market. Thanks omby
  3. omby

    HART communicators

    Hi, Can anyone reccomend a basic up to date HART field communicator for an industrial environment to connect to a stand alone transmitter for set up and calibration? Fairly happy with the now discontinued Emerson 375 & 475's but the ones I've tried lately either dont have full set-up...
  4. omby

    positioning of orifice plate

    Zdas04, the system 'works' as its part of an air/gas ratio system for a burner which is linked via a dcs to a combustion management system. The system works out gas times, heat required, air/gas ratio's etc and feedback is provided by accumulated heat and rate of temp rise being compared against...
  5. omby

    positioning of orifice plate

    Thanks Dan, those are the sorts of things I'm after. Jim, I have had experience of averaging pitot tubes and have already considered them but the gas mix in the main can be prone to condensate and I think this may be an issue with such a device. I know the current installations are not ideal...
  6. omby

    positioning of orifice plate

    Ok. How do you arrive at that figure?
  7. omby

    positioning of orifice plate

    I'm afraid we're stuck with them at present. Installation of new isolation valves downstream have meant altering the main as they are bigger than those used previously. The orifice plate installation wasn't ideal to start with, and since I joined the current project (which is not a new...
  8. omby

    positioning of orifice plate

    I have some queries regarding the positioning of an orifice plate in a vertical gas main approx 30 inches in diameter. Ideally it should be positioned with 10 straight pipe diameters upstream and 5 downstream. Assuming I only have 10 straight pipe diameters in total (a 90 degree bend at one...
  9. omby

    thermally conductive gels/pastes

    Thanks. I'll drop them a line and get more info. regards omby
  10. omby

    thermally conductive gels/pastes

    Does anyone know of, or could recomend any commercially available gels or pastes that I could use to conduct teperature to the tip of a thermocouple that is inserted into a hole drilled in a refractory brick. The gel/paste needs to be able to withstand upto 200 degs c and must not set solid as...
  11. omby

    optical pyrometry on conveyor belts

    Well, perhaps I should have missed the word 'Optical' off the thread tagline. I'm really just after the simplest, most reliable non-contact method of measuring a generally low temperature ore product that travels on a conveyor (and as such has a variable bed depth), and is suitable in an...
  12. omby

    optical pyrometry on conveyor belts

    The product is a sintered ore that is delivered from one part of a process to another via a rubber based conveyor belt. It is supposed to be suitably cooled before being put on the transfer belt and the pyro is to check that cooling process is working ok to protect the conveyor. Unclesyd, I...
  13. omby

    optical pyrometry on conveyor belts

    Has anyone had any experience of measuring the temperature of a product on a conveyor belt? Is optical pyrometry the best method? If so, does the depth of material on the coveyor affect the reading by any great amount? Are pyro's accurate at lower ranges of temperature measurement? ie <60 degs...
  14. omby

    Thermocouple basics

    Hi Waross, As I understood things..... the junction of two dissimilar metals would produce a voltage equivelent to the difference in temp between the hot and cold end of the wires. The linearity and amount of voltage produced is dependant on the types of wire used, hence the different temp...
  15. omby

    Thermocouple basics

    Waross, I think you missunderstand my problem. The converter card always adds the 10 degs ambient cj temp to the mV I inject. I am happy with this, and inject the equivelent mV of 990 degs at the card to give me an o/p equivelent to 1000 degs. When I connect my mV injector to the compensating...
  16. omby

    Thermocouple basics

    Thanks Dan. Thermocouple extension cable (compensating cable) is used from the t/c head to the tc/mA converter card. The 20 degrees is the difference in temp of the compensating cable between the field connection (30 degs) and the substation (10 degs). If I inject in the substation...
  17. omby

    Thermocouple basics

    Thanks Dan, I was reasonably sure I was right on that, but after discussing it will a colleague, I had sown seeds of doubt in my mind. I am happy that in the field, my test equipment will be isothermal, but what about the compensating cable? From the original example I gave the end I am...
  18. omby

    Thermocouple basics

    This is one point causing confusion. I always thought that due to the law of intermediate metals that because the internal wiring of the injector, leads, and point at where I am injecting in the field are all at the same 30 degrees c, that yes, other hot and cold junctions are made, but the...
  19. omby

    Thermocouple basics

    I wish to test a thermocouple loop by injecting a millivoltage from in the field where the thermocouple terminates to compensating cable, back to a substation and a thermocouple/mA convertor card with cold junction compensation. Lets say the field temp is 30 degrees c and the substation temp is...
  20. omby

    accuracy and error measurement

    Yes, I was thinking along the same lines. Once I had calculated an overall error for the physical system, I could apply it to flows adjusted for the minimum, expected, and maximum possible densities of the gas.

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