Ss Brewing Technologies Giveaway!

Home Brew Forums > Home Brewing Beer > Automated Brewing Forum > RTD help
Reply
 
LinkBack Thread Tools
Old 06-05-2013, 04:39 PM   #1
Bensiff
Mind Your Business
HBT_SUPPORTER.png
Feedback Score: 0 reviews
 
Bensiff's Avatar
Recipes 
 
Join Date: Mar 2008
Location: , Washington, the state
Posts: 4,480
Liked 305 Times on 245 Posts
Likes Given: 53

Default

Looks like I made my mistake in ordering my kettle as I didn't switch out the thermowell where a dial thermometer with a 1/4" stem fits for a TC fitting. So now I need a plan for an RTD. I really like the Auber setups with deluxe cable as I want to be able to disconnect easily at the kettle. however they don't seem to make one with a 1/4" probe and 1/2" npt connector. Aubers customer service suggested I pack the thermowell with thermal grease but that seems like it would turn into an insulating compound used that way. I thought about turning the thermowell into an RTD probe but can't find 3 lead RTDs so don't know how I would accomplish that unless I'm missing something in how those are wired. My other thought is to get a prebuilt probe in the correct diameter casing and cut the wires to tie into an auber style quick release.

Any thoughts on how to proceed would be helpful.

__________________

VOTE, n. The instrument and symbol of a freeman’s power to make a fool of himself and a wreck of his country.

Bensiff is offline
 
Reply With Quote Quick reply to this message
Old 06-05-2013, 05:19 PM   #2
rmaloney86
Feedback Score: 0 reviews
Recipes 
 
Join Date: Jun 2012
Location: Milford, Delaware
Posts: 98
Liked 8 Times on 7 Posts
Likes Given: 22

Default

Could you explain your kettle setup a little more please? What kind of kettle, where you got it from (I'm in the market for a larger kettle) The thermowell currently attached is a weldless set up that fits 1/4" npt? I must not be picking up what your putting down.

__________________
rmaloney86 is offline
 
Reply With Quote Quick reply to this message
Old 06-05-2013, 06:32 PM   #3
crane
Feedback Score: 0 reviews
Recipes 
 
Join Date: Sep 2011
Location: San Diego, CA
Posts: 295
Liked 27 Times on 24 Posts
Likes Given: 1

Default

If you take apart one of the auber RTD sensors you will find that they use a 2 wire RTD with ~2" inch leads. They solder one white wire to one of the leads and two red wires to the other lead. This is how you make a 3 wire RTD out of an RTD with only 2 leads.

Also thermal grease is not an insulator. It is a thermal conductor and works very well for conducting heat. You will definitely want to use it inside the thermal well if you make your own sensor.

__________________
crane is offline
 
Reply With Quote Quick reply to this message
Old 06-05-2013, 08:31 PM   #4
Bensiff
Mind Your Business
HBT_SUPPORTER.png
Feedback Score: 0 reviews
 
Bensiff's Avatar
Recipes 
 
Join Date: Mar 2008
Location: , Washington, the state
Posts: 4,480
Liked 305 Times on 245 Posts
Likes Given: 53

Default

Quote:
Originally Posted by rmaloney86
Could you explain your kettle setup a little more please? What kind of kettle, where you got it from (I'm in the market for a larger kettle) The thermowell currently attached is a weldless set up that fits 1/4" npt? I must not be picking up what your putting down.
It's from stout tanks. Thermowell has 1/2" female npt that has a 1/4" diameter probe going roughly 3" into the kettle. It is all integrated, not weldless.
__________________

VOTE, n. The instrument and symbol of a freeman’s power to make a fool of himself and a wreck of his country.

Bensiff is offline
 
Reply With Quote Quick reply to this message
Old 06-05-2013, 08:40 PM   #5
Bensiff
Mind Your Business
HBT_SUPPORTER.png
Feedback Score: 0 reviews
 
Bensiff's Avatar
Recipes 
 
Join Date: Mar 2008
Location: , Washington, the state
Posts: 4,480
Liked 305 Times on 245 Posts
Likes Given: 53

Default

Quote:
Originally Posted by crane
If you take apart one of the auber RTD sensors you will find that they use a 2 wire RTD with ~2" inch leads. They solder one white wire to one of the leads and two red wires to the other lead. This is how you make a 3 wire RTD out of an RTD with only 2 leads.

Also thermal grease is not an insulator. It is a thermal conductor and works very well for conducting heat. You will definitely want to use it inside the thermal well if you make your own sensor.
I have only used thermal grease when building a computer which uses the thinnest of layers if it so I was worried that loading up a 1/4" tube with it would slow heat transfer. But I suppose an air gap would be pretty bad too so something has to be in there.

So would you recommend ripping apart an auber and housing the internals in the kettles integrated thermowell packed with thermal grease, building my own from the ground up, or just using the standard auber probes in a thermowell packed with thermal grease? In the latter option I would imagine the auber probe would have a few mm of grease between it and the kettles thermowell wall.
__________________

VOTE, n. The instrument and symbol of a freeman’s power to make a fool of himself and a wreck of his country.

Bensiff is offline
 
Reply With Quote Quick reply to this message
Old 06-06-2013, 01:36 PM   #6
crane
Feedback Score: 0 reviews
Recipes 
 
Join Date: Sep 2011
Location: San Diego, CA
Posts: 295
Liked 27 Times on 24 Posts
Likes Given: 1

Default

Quote:
Originally Posted by Bensiff

I have only used thermal grease when building a computer which uses the thinnest of layers if it so I was worried that loading up a 1/4" tube with it would slow heat transfer. But I suppose an air gap would be pretty bad too so something has to be in there.

So would you recommend ripping apart an auber and housing the internals in the kettles integrated thermowell packed with thermal grease, building my own from the ground up, or just using the standard auber probes in a thermowell packed with thermal grease? In the latter option I would imagine the auber probe would have a few mm of grease between it and the kettles thermowell wall.
You don't need to load up the entire thermal well with grease. You really only need enough to make good contact between the RTD tip and the tip of the thermal well.

I wouldn't buy an auber RTD just to take it apart. It would be a lot cheaper to buy an RTD element with 1-2" leads on it and solder on three wires. I was just using that as an example of how 3 wire RTD sensors are constructed. If you are lucky you may be able to find out from auber the exact RTD they are using in their probes and buy some from Digikey or mouser.

I so wouldn't take the auber sensor and shove it into the thermal well. Stainless steal is t the best thermal conductor so adding an additional layer of it will slow down your sensors response to changes and possibly introduce an increasing offset as the water temp moves farther away from the ambient air temp.
__________________
crane is offline
 
Reply With Quote Quick reply to this message
Old 06-06-2013, 05:55 PM   #7
Bensiff
Mind Your Business
HBT_SUPPORTER.png
Feedback Score: 0 reviews
 
Bensiff's Avatar
Recipes 
 
Join Date: Mar 2008
Location: , Washington, the state
Posts: 4,480
Liked 305 Times on 245 Posts
Likes Given: 53

Default

Quote:
Originally Posted by crane

You don't need to load up the entire thermal well with grease. You really only need enough to make good contact between the RTD tip and the tip of the thermal well.

I wouldn't buy an auber RTD just to take it apart. It would be a lot cheaper to buy an RTD element with 1-2" leads on it and solder on three wires. I was just using that as an example of how 3 wire RTD sensors are constructed. If you are lucky you may be able to find out from auber the exact RTD they are using in their probes and buy some from Digikey or mouser.

I so wouldn't take the auber sensor and shove it into the thermal well. Stainless steal is t the best thermal conductor so adding an additional layer of it will slow down your sensors response to changes and possibly introduce an increasing offset as the water temp moves farther away from the ambient air temp.
Wouldn't I need to fashion a Wheatstone bridge than? Does anyone have a design for this?
__________________

VOTE, n. The instrument and symbol of a freeman’s power to make a fool of himself and a wreck of his country.

Bensiff is offline
 
Reply With Quote Quick reply to this message
Old 06-06-2013, 07:20 PM   #8
orangehero
Feedback Score: 2 reviews
Recipes 
 
Join Date: Apr 2010
Location: Northeast
Posts: 912
Liked 108 Times on 59 Posts
Likes Given: 184

Default

So what's the problem with using this?
http://www.auberins.com/index.php?ma...roducts_id=261

This would be exactly the same as the stout setup only with an RTD instead of a dial thermometer. Fill the thermowell with mineral oil or thermal compound to improve response time (again just like stout).

I think the difference in delay would barely be noticable (if at all) between such a setup and just having the probe stick directly into the mash.

__________________
orangehero is offline
 
Reply With Quote Quick reply to this message
Old 06-06-2013, 08:42 PM   #9
Bensiff
Mind Your Business
HBT_SUPPORTER.png
Feedback Score: 0 reviews
 
Bensiff's Avatar
Recipes 
 
Join Date: Mar 2008
Location: , Washington, the state
Posts: 4,480
Liked 305 Times on 245 Posts
Likes Given: 53

Default

Quote:
Originally Posted by orangehero
So what's the problem with using this?
http://www.auberins.com/index.php?ma...roducts_id=261

This would be exactly the same as the stout setup only with an RTD instead of a dial thermometer. Fill the thermowell with mineral oil or thermal compound to improve response time (again just like stout).

I think the difference in delay would barely be noticable (if at all) between such a setup and just having the probe stick directly into the mash.
That is pretty much exactly what I wanted but I was worried about the response time going through two metal casings and a thick thermal grease layer between the two.
__________________

VOTE, n. The instrument and symbol of a freeman’s power to make a fool of himself and a wreck of his country.

Bensiff is offline
 
Reply With Quote Quick reply to this message
Old 06-07-2013, 03:14 PM   #10
crane
Feedback Score: 0 reviews
Recipes 
 
Join Date: Sep 2011
Location: San Diego, CA
Posts: 295
Liked 27 Times on 24 Posts
Likes Given: 1

Default

Quote:
Originally Posted by Bensiff

Wouldn't I need to fashion a Wheatstone bridge than? Does anyone have a design for this?
No. You would hook this up just like any other 3 wire RTD.
__________________
crane is offline
 
Reply With Quote Quick reply to this message
Reply



Quick Reply
Message:
Options
Thread Tools