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Microwave Works

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  1. Jul 26, 2015 #1
    If I tightly packed oily sand in my microwave and turned it on would it heat the sand and oil? If paraffin and salt water were present would it heat everything? Could I send the microwaves to the oven from 1 mile away thru a peice of metal conduit?
     
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  3. Jul 27, 2015 #2

    sophiecentaur

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    Microwaves will travel through a metal tube or 'waveguide' with an appropriate cross section. However, you need to launch the wave into the waveguide in the right way.
    I would not advise that you get involved with modifying a microwave oven. There is a dangerous amount of power available (hundreds of Watts!!) which can harm the human body.
    You would need a professional level of knowledge to design, build and operate microwave equipment with that sort of Power. I will refer this to the Mods because it is a potentially dangerous practice and PF is not into that sort of thing, I'm afraid.
    PS There are plenty of experiments that can be done using fairly inexpensive, low power equipment. You could approach the subject that way.
     
  4. Jul 27, 2015 #3

    Dale

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    At Garyt, as sophiecentaur mentions, we can discuss the physics of microwaves here, but not the modification of microwave ovens (if you are asking this level of question then you do not have the knowledge to safey make modifications).

    Microwaves can be routed through a waveguide, which is a tube of the right size. It would certainly be substantially lossy over long distances.
     
  5. Jul 27, 2015 #4
    In an answer to my orginal question, It was stated that:Microwaves can be routed through a waveguide, which is a tube of the right size. It would certainly be substantially lossy over long distances. What is the correct size and define lossy. I am not modifying a microwave, just wondering if microwaves would work in a certain application in the oil field.

    It was also stated that: Microwaves will travel through a metal tube or 'waveguide' with an appropriate cross section. However, you need to launch the wave into the waveguide in the right way. What would the appropriate cross section look like? How big would it be? What is needed to launch microwaves in the correct way?
     
  6. Jul 27, 2015 #5

    DEvens

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  7. Jul 27, 2015 #6

    davenn

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    One of the most common ways is with a monopole probe element in the waveguide an electrical 1/4 wave length from the closed end of the guide
    its good for power levels up to 5 - 10 Watts or so
    Another method is mounting a Gunn Diode at that same position instead of a probe ... Gunn Diode oscillators have power levels up to approx. 500mW

    For really high power methods 10's to 100's of Watts cavity oscillators such as magnetrons and klystrons are used. These cavity oscillator units are coupled directly to the open end of the waveguide

    Waveguides are essentially high pass filters. That is, they have a lower frequency cutoff value
    depending on the specific type of WG. there is a whole range of WG's covering freq's from around 1000 MHz to 100+ GHz
    for example WR75 is designed to cover the ~ 8 - 11GHz.
    whereas WR42 is designed for ~ 18 - 26 GHz and 10 GHz wont pass through it without severe attenuation


    Dave
     
    Last edited: Jul 27, 2015
  8. Jul 27, 2015 #7

    Drakkith

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    See this link for an overview of waveguides: http://www.navymars.org/national/training/nmo_courses/NMO1/module11/14183_ch1.pdf
    Input/output methods are covered starting at the bottom of page 28.
     
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