Sciencemadness Discussion Board
Not logged in [Login ]
Go To Bottom

Printable Version  
Author: Subject: thermometers

Posts: 38
Registered: 28-5-2008
Location: USA
Member Is Offline

Mood: hyper

[*] posted on 13-2-2010 at 10:35

For a distilling head what kind of thermometer would you use. A full immersion(Its immersed in vapor?) Or what. I never gave it much thought tell I was getting ready to buy some new ones. Thanks.
View user's profile View All Posts By User
International Hazard

Posts: 2956
Registered: 18-1-2007
Location: UTM
Member Is Offline

Mood: LaGrangian

[*] posted on 13-2-2010 at 12:21

Thermometers are calibrated to a mark on the stem. For a distilling head you would want one that is calibrated such that the measuring portion (bulb to line) is in the head. The bulb should be just below the takeoff so that the thermometer measures the vapor temperature as it enters the cooling part of the still. Measure the distance from the top of the still head to the takeoff and order your thermometer calibrated over that distance. Some still heads have a ST built in to accept a thermometer with a ST taper. I have two like this. I prefer the Teflon adapters because they are adjustable and thermometers without the taper are much easier to get. Plus the same thermometers can be used in certain types of melting point apparatus.

"When you let the dumbasses vote you end up with populism followed by autocracy and getting back is a bitch." Plato (sort of)
View user's profile View All Posts By User
Arthur Dent
International Hazard

Posts: 546
Registered: 22-10-2010
Member Is Offline

Mood: entropic

[*] posted on 23-1-2011 at 10:38

Sorry to revive this antique thread, but I have a quick newbie question about thermometers...

I have this old Stansi mercury thermometer (Germany), 30 cm long, with a yellow line background, rated from -20C to 110C, with an eyelet at the end to hang. Looking at the back, it does have a mark about 2/3 of the way up, right next to the brand name.

That means that when I use the thermometer, I must push it down the rubber stopper so that 2/3 of the body is inside the vessel, right?

It doesn't matter if it's in the liquid or just above it... it just has to be right at that mark on the stopper, correct?

I have been using a digital thermometer ever since i've started my home chemistry endeavors and it's fairly accurate (boiling distilled water at about 102C, hey, I paid ten bucks for it!) but for some experiments where the liquid will be boiling for a long time, I decided to pull out this old thermomether which I really never used, and I just want to set it up right.

The vessels I'll be using are a 3-neck 250ml boiling flask or a 1L erlenmeyer flask with a 3-hole rubber stopper.


P.S.: After googling a bit, I learned that Stansi was purchased by Fisher Scientific in 1967, so yeah, it's a vintage thermometer, probably older than my miserable old carcass... LOL

--- Art is making something out of nothing and selling it. - Frank Zappa ---
View user's profile View All Posts By User

  Go To Top