Pictures of the new heat exchanger I built.

[KBRENNY]

Here are some pics of the new heat exchanger I built. I run it inline before the little giant 4HT propane water heater to give it a little boost and reduce the frequency of having to find someplace to fill up the propane tank. The main pipe is sched 80 seamless 4", the inner tubes are 3/4" sched 80, the end plates are 1/4". All 304 stainless steel.

these are the components before welding, I had the end plates water jet cut.

this is the center assemble before it was welded

after the welding shop was done

I wrapped the entire tube with fiberglass insulation
then fabricated a cover out of aluminum
cutting out holes for the fittings and feet

It holds a steady 175 to 180 while cleaning at a normal speed but will reach 200 if I am making an extra forwards and backwards dry stroke at 500 psi and 12.5 flow

 

[TimP]

That's pretty awesome for one exchanger. That's definitely gonna save you some money. And it probably didn't cost you too much to build, how does it effect your TM as far as back pressure etc? I wonder how long that exchanger will take to pay for itself in LP savings.

 

[The Preacher]

dude, ya do some kick ass stuff!

 

[Jay D]

TOO cool for school. I wish I welded that good, much the less stainless.

 

[Shawn Forsythe]

What did you get for a back-pressure reading at the engine manifold?

 

[KBRENNY]

I do not know the back pressure created by the heat exchanger but I know the engine RPM has not changed at all. It runs the same RPM range as it did before the install. This HX is installed after the muffler which should create more back pressure than the HX. I am not sure on propane savings yet as I filled my propane tank up as soon as I was finished with the install and marked the hours on the unit. I will let you know when I have to fill up with propane again. The water coming out of the HX was hot enough to cause the thermostat on the little giant to stop firing because of the waters inlet temp so I have now had to turn up the little giant so it will actually fire when wanding. Before the HX I was running 240 ATM and 220 ATW, Now I am running 255 ATM and 230 - 235 ATW, and the propane burner is firing at least 1/2 as much as before.

 

[Shawn Forsythe]

It's always a good idea to know the resultant backpressure after you add ANYTHING to the exhaust system, especially to an existing silencer setup. I'm not saying it's applicable, because you don't know unless you test, but any exhaust (even stock), can already be close to permissible limits.

 

[Mike Draper]

I pretty much copied your design with a few changes then installed the HX in place of the muffler beneath my van. Works very well. Only difference is I added more circle plates every 4 inches down the pipes so the water would have to work it's way from the inlet to outlet. I'm getting 290 at the truck now with this setup. However, I first run the water through a large coolant HX that brings the water to about 195-200 before in enters the exhaust hx. Actually less back pressure now then before with the muffler on. And no, it's not much louder. Sounds like I have a flowmaster muffler on now. Wrapped it with Header wrap too.

 

[Greenie]

Mike, this is tied into the van's exhaust, what provisions do you have in place for a releif valve when water isn't flowing, also what about freezing in the winter?

 

[Mike Draper]

Well, that's a good question. Whenever I'm driving I open the hot water relief valve and that's lets the pressure out. I have a hose that runs straight down through the floor of the van. (their is always pure steam coming out of it when I'm driving) Having the valve open doesn't neccesarily let water out, just pressure. As far as freezing goes, I have a heated garage and that won't be a problem. Whenever I'm driving or the van is running that won't be a problem either. However, there is still an in and outgoing line, they could possibly freeze. So far when the van is running steam slowly circulates through both of these lines up to a bypass I've made in the upper part of the van. I've also ordered some specialized flexible insulation tubes that will go around the stainless lines that can handle exhaust temps, but also help keep it from getting to cold ( also I can contain the heat loss in the winter). All in all it's rather simple setup, however it might not be for the everyday carpet cleaner especially in cold climates. I"m going to post some pics here when I get some time in the next couple of days or weeks. Or maybe post a video with a youtube link.

 

[floorguy]

i tell you what...build me one and i will give it the floorguy SOA..

seriously though...if you did in fact, let me know how much...i have been wanting one off the engine for sometime...and to get rid of my damn blower one...(damn it makes things difficult)

besides greenie would like to hear from ME on it :wink:


ohhhh and dont lie about the freezing....you guys up there are about the only place that could FREEZE OVER HELL

 

[Greenie]

look forward to pics.

 

[Mike Draper]

new pic's of temp gauge at the machine. Sorry about the size of pic's

 

[TimP]

If all the kinks could be worked out in this design I think it would be pretty awesome. You could get rid of restriction in blowers in these PTO systems with blower exchangers etc. And get the heat from the exhaust and have true single wand mini vortexes. We could run the blowers at full RPM and let them breath. Just think of the fuel savings.....

 

[Larry Cobb]

Kevin;

Nice work on the HX.

I would install the HX before the muffler to deliver more heat from the engine.

Then you could use a less restrictive muffler to minimize the engine back pressure
(I have one).

I would also replace the flex pipe with bent tubing. The flex will be the weakest link in your entire exhaust system.

Larry

 

[AshleyMckendree]

Very Nice... but where did you get your supply's?

I have never been able to track down a SS pipe supply of anything larger than 3' OD

 

[Mike Draper]

Steel fabrication or machine shops in your area might have some supply or can lead you in the right direction. I run Schedule 40 wich is plenty thick and it's not seamless. Neither is the other guy schedule 80. If it was really seamless it would have been machined out of a solid piece of stainless steel, wich would probably result in a$1500 price tag for that little piece. My sched 40 was about 6" round and 3-3.5 feet long, About $90.00 a foot. If you can't find any, e-mail me and I'll get you in touch with my local steel mill, they have it in stock.

 

[TimP]

I can get galvanized steel pipe as my inlaws run a fence biz. But it will rust out over time I'm sure.

 

[Larry Cobb]

Ashley;

We have 5" SS Tubing end cuts left over from our HX's.

How long did you need ?

I'll trade you for a REAL PTO TM.

Larry