July 04, 2020, 12:23:10 PM
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Topic: Need help identifying this container/Dewar  (Read 225 times)

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Offline boattow

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Need help identifying this container/Dewar
« on: June 19, 2020, 11:55:52 AM »
Hello,
I'm working on trying to recreate the findings from a scientific paper.  I'm an electronics guy, not chemistry and this is more of a chemistry problem than an electronics one.  I need to purchase a container but have had no luck finding one after many hours of searching.  I wrote to the authors with no response.  Attached is a picture of it.  I believe it is pyrex glass.  I suspect it is going to hold somewhere around 175ml to 200ml and is 5 to 7 inches long.  I would greatly appreciate it if anyone can point me to this.  What it's called or where I can buy one. 
Thanks for any help.
CS

Online hollytara

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Re: Need help identifying this container/Dewar
« Reply #1 on: June 20, 2020, 12:01:18 AM »
A "Dewar flask" is a double-wall flask where the inner space is evacuated - it is also called a "vacuum flask" or "Thermos" (usually the latter if sold for keeping food hot or cold). This was invented by Sir James Dewar back in the 1800s.

In the lab, it is often used to store cryogens, like liquid nitrogen.  The vacuum provides thermal insulation from the environment.  Lab Dewars are typically silvered - this increases the insulating power.

Typically you would get a Dewar from a glass company - Ace Glass and Kontes are two big outfits, or big lab supply companies like VWR or Fisher also carry them.  If the one you need isn't stock, they will make it custom. 


Offline rolnor

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Re: Need help identifying this container/Dewar
« Reply #2 on: June 20, 2020, 06:06:56 AM »
They are also sold on ebay but rather expensive even if they are pre-owned.

Offline boattow

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Re: Need help identifying this container/Dewar
« Reply #3 on: June 20, 2020, 06:46:48 AM »
Thank you for the responses.  If you look at the picture I posted in the original post, the center is hollow.  Looking at it from the top, it would look like a donut shape.  This container must be made of glass because it will have silver foil strips applied to the outside to form a coaxial cavity resonator.  Capacitors will be utilized to create a tuned circuit.  It sounds like this was custom made but I really thought it was an off the shelf item.  Thanks again.

Offline rolnor

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Re: Need help identifying this container/Dewar
« Reply #4 on: June 20, 2020, 07:46:13 AM »
If you need exactly these dimensions you will need to order this from a lab-glass maker, it will not be cheap I think. Normaly Dewar-flasks are silver-coated.

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