Why, oh why, can't this just fit together like Legos?!

February 22, 2012 10:03 PM

Plumbing/Science Equipmentfilter: I have a process air heater that I bought from Omega but I have no idea how to connect the 4in non-threaded duct and the 1in threaded pipe outlet from my blower. Help please!

I'm a researcher trying to hook up a simple air heater between my air blower and my air manifold, but how do I make them connect?

I'm looking for a way to install this:
http://www.omega.com/pptst/AHF_HEATER.html

It's a flanged air duct that has three bolts in the flange. I need to connect a 1 inch threaded outlet from an air blower to a 4 inch non-threaded pipe where the hot air will go. The only problem is that I have no idea how to install it (without welding) in a way that is air tight and does NOT use adhesive (I need to take it apart periodically).

(Bonus points if I can buy the solution at Granger.)

posted by wuzandfuzz to technology (8 answers total)

Are you sure this (apparently tiny) blower with a 1" outlet can move enough air to keep the heater from overheating? Seems a little unlikely...

Do you want to mount the blower to the flanged or non-flanged end of the heater? Do you know what type of thread is on the 1" blower outlet?
posted by jon1270 at 1:28 AM on February 23, 2012

I've found McMaster-Carr's online catalog helpful in the past. Their search engine lets you put in a single term and brings up lots of categories, and it has helpful images. (even though I think the prices at Granger may be better in some cases). Also, give the guys a call at either and see if they can help you find what you want; I've found them really helpful in the past, even when I'm asking completely bizarre questions (which you're not).
posted by sciencegeek at 4:05 AM on February 23, 2012

Jon, Yeah, the blower moves a ton of air. The heater is low wattage anyway - it maxes out at low power.

I want to mount the blower to the flanged side - on the blower side it's just 1in NPT pipe. Seems like there should be a flanged, threaded pipe I could bolt onto the heater flanges and put a nipple in between w/ teflon tape and call it a day, but the size is quite irregular - 2 3/8!

That's why I'm hoping the hive mind has come across some sort of simple, pipe connecting adjustable solution that doesn't require custom fabrication. any engineers or mechanics out there with a simple tool or part I can buy?
posted by wuzandfuzz at 8:27 AM on February 23, 2012

Sounds like you could just attach a floor flange to the blower outlet, drill some new holes in the floor flange and bolt it to the heater flange. If the floor flange's major diameter isn't large enough, then you might have to stick another piece of sheet metal in there to make up the difference. The tools required wouldn't be anything fancy.
posted by jon1270 at 8:44 AM on February 23, 2012

Okay, let's try this link.
posted by jon1270 at 8:45 AM on February 23, 2012

I also use the same heaters in my research. The heater itself is not air tight. Well my size wasnt. Maybe yours is constructed differently. There is a rivet on the opposite end from the flange. I cut the flange off and put the heater inside a larger pipe and sealed the mounting bolt holes with high temperature silicone. Then it was pipe fittings all around. Use good pipe sealant or teflon tape to make pipe threads gas tight. That was important for me because I was measuring flow up stream of the heater.

Omega has a guide on their site to calculate minimum flow rate to prevent burn out.
posted by KevCed at 10:48 AM on February 23, 2012

ok so to recap:

I searched McMasters. McMasters is MUCH better for searching than Grainger! I found it easiest and fastest to search McMasters, then buy on grainger since I have one a few blocks away.

On the non-flanged end:
I ended up using a pipe repair clamp, which is a heat-resistant (180F) 2.5in diameter rubbery tube (neoprene) with a circular clamp providing pressure to seal it down. I checked for leaks via soap and man, it is not going ANYWHERE. No real leaks. Wide dia heaters like this are usually for high flow low psi apps like mine anyway.

One the flanged end:
I clamped a floor flange per Jon's suggestion that was threaded on the inside to the flange. I bought three tiny C-Clamps, a 700F rated gasket, and stuck it all together. Checked for leaks, and it is also SOLID. no leaks, for such a janky build.

Other notes:
my purchased heater pipe/element was airtight. all welded. Junctions even. if you need a cheapo way to get this done the omega model is easy to play with. Still haven't wired up the PID but the air flow transfer is leak-free.

Also, with three C-Clamps/Floor Flange, this thing is HEAVY. Find out what the weight of everything is not just temp resistance.
posted by wuzandfuzz at 11:07 PM on February 25, 2012

Glad to hear it worked out leak-free but a word of caution about the neoprene clamp.

I originally used a the same thing (from McMaster even) on the upstream (unheated air) connection and it melted. We figured it was not just radiation from the heater wire whose temperature is high enough to glow red/orange during operation but also conduction from shell which was not safe to touch meaning at least 60-70C (140-160F) but possibly hotter.

I was in the mid range of flow for my heater, heating to 80C. If you are in the high-flow range or have a lower-power heater the element and shell of the heater might be cooler and you could avoid melting the clamp.
posted by KevCed at 6:27 AM on February 26, 2012