how to mount RTD to 12' dia vessel? 1

[USAeng]

Have to figure out how to mount the attached RTD to a 12' diameter stainless tank. It conditions biogas and currently is doing so. Best suggestion so far is large stainless hose clamp. Don't know where to get one that big though. Any other suggestions? I thought about welding it to the tank but not safe with the biogas in it and will also be getting 4" of insulation on top of that - so changing in the future is going to be tricky no matter what unless there is a good solution

 

[USAeng]

it is measuring outside temp of the tank for freeze protection

 

[IRstuff]

seemed to be at least a few hits when I searched:

http://www.amazon.com/Stainless-Steel-Hose-Clamp-1Pair/dp/B005JWGBGQ/ref=pd_sim_sbs_indust_2

Some thermal compound to improve thermal conductivity is probably in order

TTFN
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[USAeng]

12 foot diameter vessel

 

[IRstuff]

Oh, sorry. Nonetheless, since the only part that needs to look like a clamp is the last few inches, so of you have welding capability, I might suggest cutting a large hose clamp and welding a steel band in the middle to augment the length, since there is no structural strength required, other than to hold the sensor against the tank.

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[SnTMan]

Steel banding, like used for shipping, etc?

Regards,

Mike

 

[hacksaw]

tack welding is the usual means

clamps are not suitable, someone is pulling your leg with that one

 

[USAeng]

I thought the clamp deal was BS too... Except it is coming from the manufacturer's sales engineer. Kinda sad. Maybe we can weld a sleeve that the pad can slide into so it can be replaced. My only worry is first we will have to purge all that gas and second we have to make it so the rtd can be replaced without damaging any insulation

 

[USAeng]

I should say it is coming from the heat tracing manufacturer sales engineer. Not the RTD

 

[LittleInch]

Why don't you use a temp transmitter designed to be strapped on rather than trying to use your current version which looks wholly unsuited to not being glued or otherwise fixed to the surface? Think laterally.

I tried "strap on temperature sensor" into MR google and plenty came up. (Make sure you add the "temperature sensor" bit or you get some different results....) Plenty of those have straps - hell my hot water tank has one very much like that...

My motto: Learn something new every day

Also: There's usually a good reason why everyone does it that way

 

[JStephen]

You CAN get hose clamps that would physically fit. No idea about how well the idea would work, but lack of length isn't the issue:

http://www.mcmaster.com/#catalog/120/296/=qmwfju

I would guess the supplier that suggested it was accustomed to mounting stuff on pipes.

 

[USAeng]

Supplier is looking into different type of RTD. I totally agree there must be something better. Thanks for the nudge in the right direction!

 

[MintJulep]

Peel and stick!

http://www.omega.com/pptst/SA1-RTD.html

 

[MikeHalloran]

"Band-It" clamps comprise a small clip and a length of strap pulled from a roll, tensioned and cut by means of a special tool and clinched with a hammer, so 12 foot diameter is no problem. I'm guessing that stainless would be a better choice in this application, but aluminum is available for light duty stuff like retaining insulation covers.

Once installed, they look like hose clamps; the sales engineer might have seen them installed somewhere.

McMaster-Carr carries them. See 5422K28 and related items.

They also carry a no-special-tool equivalent 5540K11 that looks interesting, but with which I have no experience.





Mike Halloran
Pembroke Pines, FL, USA

 

[moltenmetal]

Be careful with adhesives because the last thing you want is heat trace trying to warm up a sensor which has come away from the heated surface. Then again, the heat trace guys are just going to hold it in place temporarily with aluminum foil tape. The insulation is what ultimately will hold this together. No insulation supports on the tank? The insulators, when nobody is looking, will use a stud welder to pop little studs onto the tank. Yes, it violates ASME (it is a weld to the pressure boundary, after which a repeat of the hydrotest is required, which they will not do), and yes it's done all the time.

12' is a LONG way to go round with a clamp. I'd suggest pallet banding rather than trying to string together hose clamps into a 12' diameter loop. You can attach an RTD to that easily enough.