Pid Control - Sensors (thermocouple)

[Crazy]

I have a T on the exit of my herms with the thermocouple. I prefer this to having the probe on the exit into the mash as I know exactly what temp my wort is at as it passes through the herms, Screwtop put me onto this and I think my consistency has improved because of it (thanks Screwy).

Andrew

Is your heat exchanger on the herms direct heating the wort or as mine is heating the water around a copper coil that caries the wort? I have been playing with probe positions latley to try and get as even a temp as possible through the mash and have found about an inch under the surface on the opposite side of the tun seems to work the best but I am still not compleatly happy.

Cheers Derrick

 

[Gout]

ok i have a sensor and a fitting that fits (found it in my box of bits) however i am not sure of the best way to fit it.

Stainless T pipe. if it goes in one way (pic one) it only leaves about 2mm around the sensor for the fluid - i think a big restriction?

pic 2 its just in the flow at the tip - giving good flow but maybe poor sensor placement

can anyone tell me the best method

 

[Gout]

Does anyone know where i can get 1/4 NPT barbs and or a fitting i can use to attach one of these T pieces to a copper pipe (used in my herms coil)

My setup is far less stainless the schooey's example so i will have a plastic pipe as my herms outlet into the tun - insulated. The same as above T piece, and somehow attach the T to the copper coil like a compression fitting or as a last attempt 1/4 NPT barb and a plastic pipe to join them. This will not be the final solution but i want something to start with and then play about to get everything set up as i like, then improve my fittings setup.

Anywhere in Melbourne would be nice, i would even use brass if bunnings or the likes have them - as i said to get this just set up.

I looked at swagelok but the amount of fittings, names, materials etc confused the heck out of me

 

[egolds77]

I have a sensor at the exit of the heat exchanger which then runs back into the Mash Tun esky through a 30cm of tubing which flows into the esky at the opposite end of the esky outlet. The Mash Tun sensor is at the exit, which flows back to the heat exchanger. My theory is that these are the two points that you are trying to equilise/match. You don't want to over heat the wort past your mashing temp with your heat exchanger so at the heat exchanger outlet makes the most sense. So far with my system setup it seems to work really well. Once the Mash recirculation has sabilised, there is only a 0.2 degree C difference between the 2 points.

My HERMS heat exchanger heats water surrounding the copper coil which the Wort is flowing through.

:icon_chickcheers:

 

[kirem]

probe from auberins, float switches from jaycar, water solenoids borrowed

fittings from beerbelly

custom fabricated SS HEAT EXCHANGER

View attachment 28729

 

[Gout]

Hi Elton, i plan to have it on the exit of the HERMS coil which returns to the mash like you. My only issue is introducing the sensor into that possition as its a liquid tight 1/4" NPT so i have a T thats the correct thread but i now need to add this to the system - copper pipe or a barb.

cheers

 

[Gout]

Kirem, thats the sensor and the T so i think thats a great help ( i will have a look for something similar)

thanks

 

[kirem]

inside the heatexchanger

View attachment 28730

 

[kirem]

Kirem, thats the sensor and the T so i think thats a great help ( i will have a look for something similar)

thanks

I had to get 1/2inch to 1/4inch threaded bush/reducers. there is a correct name for them. perhaps if you order them from beer belly and just tell him you want the same thing I ordered.

Otherwise I'll try and remember what the correct name is for the part.

 

[Gout]

ah thanks, i was looking like mad and could not spot a 1/4" barb. thats a shame as i cant use all these T's i have. But that would help resolve the flow issue i had around the sensor within the T.

cheers

 

[kirem]

ah thanks, i was looking like mad and could not spot a 1/4" barb. thats a shame as i cant use all these T's i have. But that would help resolve the flow issue i had around the sensor within the T.

cheers

the T and barb are 1/2"

the 1/2inch thread is welded on the outlet of the heatexchnager

the 1/2inch to 1/4inch adapter fits the T so the probe can screw into it.

 

[Gout]

I now have the sensor setup and barbs for a test setup tomorrow or friday, and reading the instructions for the PID i see there is a Auto tune - function. Can i do this with a test run with only water? or do i need to mimic a brew (with grain)

does this mean the PID needs a tune for different size batches?
Is it safe to tune it on a real beer (if i need to use grain to tune it)

cheers

 

[raven19]

Bump - PM also sent Gout, keen to hear how this turned out in your brewery.

 

[Gout]

G'day Raven, the sensor and HERMS system now works a treat! i love it!

The first T was small and it got blocked up a few times - a real pain in the bum. I upgraded it to 1/2" (beerbelly) and a reduction thread thingy (Geordi SS) and barbs (Beerbelly) and now its great- holds temp within lets say 0.2deg (and everytime i look its spot on temp)

I must admit to being a bit lazy on the build (as i have just returned to uni as a oldish fart) but in the current state its working really well
If you require any further info then please let me know - i am not the best herms brewer but would love to help another brewer as many have me!

edit:

I have added a second PID to control the HLT - overkill but it looks good in the control box having 2 of the same and to be honest at the slight extra cost i was happy to use something i already knew how to use. The stainless sensor also worked well so i wanted to stick with it.

SSR i had some but the ones on the web site also work well http://www.auberins.com

mains power - so legal warnings apply

 

[kevin_smevin]

Anyone know of a PT100 RTD sensor that comes with a 1/2inch BSP thread. Really want to avoid having to use a heap of adaptors etc.

 

[razz]

Anyone know of a PT100 RTD sensor that comes with a 1/2inch BSP thread. Really want to avoid having to use a heap of adaptors etc.

Would you settle for 1/4" yum yum yum?

 

[schooey]

Anyone know of a PT100 RTD sensor that comes with a 1/2inch BSP thread. Really want to avoid having to use a heap of adaptors etc.

See post 18 of this thread. Small head PT100 RTD, high accuracy version (+/- 0.1C)... $45 from pacific sensortech. Fitting was $21 from T&S Valves. IMO, buy the cheapo PID, they all run very similar logic programmes and are basically calculators on roids, and spend your money on the probe that gives you the best accuracy.