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Microwave stirrer add-ons

  [vote for,

Last week I saw an idea on here, whose identity I now cannot remember, that inspired me to think of a device that would go inside a microwave oven, stuck to the ceiling or wall, to stir your food/drink as it was rotated by the turntable. Alas, that's already been invented: [1]. I also saw one that replaces the turntable with a magnetic stirrer (with gearing so it's faster): [2]. Today I saw another device to stir the contents of a microwave oven: [3].

However, that one today inspired me to think again of the other kind of stirrer that a microwave oven might have, the mode stirrer. (Last week, when I had been thinking of posting a food stirrer, I was thinking I'd have to say that it wasn't the usual kind of stirrer for a microwave oven to have.) A mode stirrer is usually used in microwave ovens without turntables; it scatters the radio waves around in a changing way so that there aren't hot and cold spots in the food. (The turntable accomplishes the same by rotating the food through the nodes and antinodes of the standing waves.)

But why not combine the two? Indeed, a few microwave ovens do have both a turntable and a mode stirrer. But most don't. So, to add a stirrer to turntable-only models, I have come up with something. Two somethings, actually.

The first is a small stirrer wheel, looking like a center-of-gravity symbol (circle with alternating quarters filled and empty) made of sheet metal, mounted on a tiny self-adhesive base. Its axis is vertical. Its edge has a soft rubber tire. It pops off the base for cleaning. Just put it inside your microwave oven, on the (cleaned) floor, next to the turntable, and slide it until its tire makes good contact with the edge of the turntable. Make sure it's not touching the walls. Then, while holding it in place, pull the red tab underneath the base. This pulls the adhesive pad's backer off, starting from the far side, so it sticks down without disturbing its position.

Hidden in the middle of the base is a tiny spring-loaded metal point, pointing downward, connected to the axle that the stirrer wheel rotates on. On first use, the microwaves will charge up the stirrer to a high voltage, as with any other metal in the microwave oven that isn't connected to the enclosure. This will cause a spark between the metal point and the floor of the microwave oven, blasting through the paint. The spring will then drive the point into contact with the bare metal, at which point the stirrer will be (electrically) part of the enclosure, and will no longer present a spark or arc hazard.

Obviously, when the turntable turns, the stirrer will spin much faster (because it's much smaller) and the cooking will be more even. Being in the corner and no higher than the turntable, it won't get in the way.

I was going to say the second was even simpler, but it turns out to be more complex now that I think about it properly. Actually (coming back up here now that I've written the description of it) it's at about the same level of complexity. It primarily consists of a piece of sheet metal just smaller than the glass turntable, with some holes in it. The edge is rolled under so that it's not sharp. The top has a non-slip rubber coating. You simply place it between your turntable and the frame under the turntable that has three little wheels on it. You also replace those wheels with the included metal ones. You also sand the paint off of the floor of the microwave oven where those wheels roll, or just wait for them to clean the paint off themselves in the same manner as an electric train self- cleans its tracks. As the turntable turns, the holes in the disc do too, stirring the waves.

N/A [2018-12-13]

notexactly, Dec 13 2018

[1] Food stirrer that attaches to the ceiling https://www.bookofj...r-even-heating.html
Found a page with actual details, a minute after saying none existed. Product page is still down, though [notexactly, Dec 13 2018]

[2] Turntable motor-powered magnetic stirrer [PDF] https://www.belart....tions/937040040.pdf
[notexactly, Dec 13 2018]

[3] 3D-printed milk stirrer https://www.thingiverse.com/thing:1468471
Mounts on the cup and uses a stick that sticks into the corner to drive the stirrer [notexactly, Dec 13 2018]

[4] How to replace the stirrer holder [YT] https://www.youtube...watch?v=MOIwT2feBOs
[notexactly, Dec 13 2018]


       Mode stirrers have to be interposed between the magnetron waveguide and the oven chamber to work effectively. Since the geometry of the node/antinode pattern within the chamber is - without a stirrer - fixed, there is no guarantee that your add-on device will have any significant effect on the energy distribution if it doesn't by chance intercept a node.
8th of 7, Dec 13 2018

       The stirrer in [4] doesn't seem to be located // between the magnetron waveguide and the oven chamber //, though I guess, because it was designed in from the beginning, they were able to design it to intercept a node. Perhaps the small add-on stirrer should come with some heat-sensitive paper to be used to map the standing wave pattern in your microwave oven to find the best place to install it. The platter-sized stirrer should be large enough to intercept several nodes.
notexactly, Dec 13 2018


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