Flash boiler project #2

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FSR402

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This project was inspired by Brewpastor and my craftsmanship by BM.

After reading BP's thread about the flash boiler idea I knew I had to do this. Most of my brew day is spent waiting for things to heat up. And I'm moving up to 30 gallon batches soon so this is only going to get worse.

So I quickly slapped together something that I thought may work. It was 20 feet of 3/8 copper tube rolled into a stainless charcoal starter tube and placed onto an extra burner a friend gave me. It worked for the most part but was not very efficient. With the tap water coming in at 67* I was able to hit a exiting temp of 192* at a flow rate of one gallon at 3 and a half minutes. And with a very small move of the valve it was down to 130*. This was with the burner kicking for all it had. and wide open water flow would get me to about 90*.

With a little more thought and looking around the house I found a Korny keg that I had that was shot. The gas in port threads were all screwed up. Perfect I thought, so I cut the bottom off, removed the rubber handles with a screwdriver and a map gas torch. Took the keg and burner to work where I welded 4 plates to the burner to hold the keg. Then I placed the keg on the burner and fired up the plasma cutter. Cut holes thru the plates and the keg at the same time then cut two slots up the sides to have a place for the tubing to go thru.
I then took 50 feet of 3/8 copper tubing and rolled it around a 4" PVC pipe. I rolled it up the length for the keg and then back down.
My thought was that if the water was going in and then up, then down and out it would give it two points it would be in contact with the flame and spend more time in the intense heat.

My test run tonight went well and I see room for improvement.

Tap water coming in was 63*
at full flow I was getting a flow rate of 3 gallons per minute.
With the burner at full bore and water at full flow I hit a max temp out of 113* (a 50* increase)
It took some playing with flame and water flow but I managed to hit my mash in temp that I need of 175* at a flow rate of .555 gallons per minute (one gallon took 1:52). Not as fast as I would like but I think I can get this better. I was not able to get a good flame (a lot of yellow fire) so I will add some air holes around the lower part of the keg near the burner.

The valve was still really touchy. There was a point where it was to fast or two slow so I think I'm going to add another valve either inline with the one I have or on the out port . My thought is that it would allow me more control and get me out of that touchy point in the valve.

But this may be perfect the way it is. I'm not looking to rid myself of my HLT just get the water into there either at temp or damn close to it. I brew using water from my hot water tap (water heater is 3 years old and always gives me clean water) so in this case my water would be going in at 120*, with a full flow rate of 3 gallons per minute with a temp increase of 50* that would put me within 5* of my mash in temp of most my beers.

This would mean that I could be mashing in (theatrically) in 1-2 minutes. As it is it takes about a minute to fill the HLT then about 30 minutes to heat it.
My next thought was that once I go to a pump system I'll be able to pump the wort from the MLT thru the boiler and into the kettle. Not getting it to boiling but I'm shooting for like 200 - 205* so then it would not take me long at all to get 40 gallons to a boil.

Here are my pics, now post your thoughts.
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That's awesome! Do you have any more pics of the construction? Keep us posted!
 
No I put it together at work and I did not have a camera there.

It's held together with two 3/8-16 rods and nuts on the outsides. The coil is sitting on the top rod holding it up about 4 inches above the burner.
 
So you have the tap water pumping through the copper over the flame? And by the time it comes out it is super heated?
 
Yes from tap water to 300 deg F superheated steam in one step in stainless steel tubing, steam is mixed with circulating wort for step mashing. At .8 gpm this will give a 49 deg F. rise in temperature at max boiler fire on old system. This steam into wort method makes step from 125 to 152 deg F. possible in about 11 minutes with 13 lbs grain and 1.3qt/lb water ratio. Temperature control is by turning burner down as wort from mash increases in temperature, boiler water flow is held constant at 3 GPH. Dilution of the wort is not a problem as the water used is less than 2 qts during step cycle.
 
As kladue said, you need to eliminate that heat chimney in the center of your apparatus there - I'd bet 50% of your heat is lost there, going straight up and out, path of least resistance. Get a steel tube with a plate on one end and stick it in there, you'll probably get much better than a 50 deg single pass rise.

I use a pressure cooker to steam mash, I do all my heating/boiling on the stove, I can get my mash (usually about 14lb) from protein rest to saccarification in 12-15mins. Heating with only steam, 9qt pressure cooker 1/3 full of water.
 
Ok that make sence, did not even think of that. I'll see what I can get the coils to do, that stuff is hard to bend now, or if I can't bend them enough I'll try the plug down the center. :mug:
 
Do you leave the corny lid in when you boil? Are the dip tube ports providing enough of a vent for exhaust? One Idea I had was to get a single chromed out header for a car and attach it to the side of the corny. That'd redirect the exhaust and be bitchin' all at the same time.
 
I'd put a capped 2" pipe down the center and leave the lid off. If you don't provide an exhaust, a lot of the heat will be lost out the bottom. I'm surprised that you're not totally thrilled with 1/2 gallon per minute performance. It takes much longer to bulk heat. IOW, heating 5 gallons of strike water would normally take longer than 10 minutes.
 
Do you leave the corny lid in when you boil? Are the dip tube ports providing enough of a vent for exhaust? One Idea I had was to get a single chromed out header for a car and attach it to the side of the corny. That'd redirect the exhaust and be bitchin' all at the same time.

What I did was I had the corny lid in the hole but it was hanging there and off to one side. I could move it around to vent it more or less.

I have cut 2 inches off the bottom of the corny now to get more air to the fire but have not played with it to see if it worked.

The plan was to do a 25 gallon batch of BM's Centennial Blonde this past weekend but my founds ran short so I pushed it back a few more weeks. Maybe by the end of the month.

As for the rate of flow I'm fine with it. But I think that if I can get a better (read more) heat out of the full flow it would be a lot easier to control the temp with just changing the flame.

My idea is I would run the water thru this and into my HLT where I can make adjustments as needed.
Once I get a pump I plan to use this to help get things to a boil faster also. Could even use it (with light flame) to do step mashes and mashouts.
 
So did you have an all rubber top, or just a corny with a single handle? I don't have a mapp torch, but I do have a propane one for plumbing...think I could melt the rubber that way?

As to valves for control, I'd be careful about putting one on the out....you don't want the potential to build pressure in the system unless you want steam burns, etc.

Good info on keeping room on the bottom....I figured the burner had an adjustable orifice for intake, but I guess that's not enough.

I am so stoked to do this. I'm thinking about mounting the thing to a diamond plate base and putting it on the bottom shelf of my new rig. If I can find some cheap chromed exhaust tubing, I might even use that for intake/exhaust...
 
So did you have an all rubber top, or just a corny with a single handle? I don't have a mapp torch, but I do have a propane one for plumbing...think I could melt the rubber that way?

As to valves for control, I'd be careful about putting one on the out....you don't want the potential to build pressure in the system unless you want steam burns, etc.

Good info on keeping room on the bottom....I figured the burner had an adjustable orifice for intake, but I guess that's not enough.

I am so stoked to do this. I'm thinking about mounting the thing to a diamond plate base and putting it on the bottom shelf of my new rig. If I can find some cheap chromed exhaust tubing, I might even use that for intake/exhaust...


Mine had the rubber top. Used the mapp gas to heat it and a regular screwdriver to pry it off. Then I used the toruch to burn off the rest. Then I sand blasted it to get it looking better.

As it was the burner did not change from half to full open and the flame was nothing like it was with nothing on it. So I know it was not getting enough air.


I really think this will make a brew day a lot faster, even more so once I get a pump.
 
I'd just like to say...there is NOT enough discussion about such an awesome piece of equipment. C'mon guys....we're on the verge of going sub 4 hours on an all-grain brew!
 
Instead of cutting up a corny keg why not use a 6" dia. piece of stove pipe as the tube. When you install the burner you need about 3-4" of clearance between top of burner to the bottom of the coils , and a gap between burner and tube for additional air to let gas burn completely. As to the tubing the coils need to be spread to completely fill inside of pipe so the hot gasses have to go through coils instead of up a central chimmney, here is an example Picasa Web Albums - Kevin - Boiler. Here is a reason that the flash boiler speeds up my brew day, from cold start to temperature in 45 secondsPicasa Web Albums - Kevin - Boiler Test. With a mass flow controller and a pid controller with a 0-5VDC output, one could automate the gas flow control for maintaining temperatures.
 
I looked at the stove pipe at lowe's, but it ain't nearly as pretty as the SS. Maybe I could go that route to work out the bugs, then sacrifice a corny to the beast.

I plan on using 50' of 1/2" copper tube from a B3 immersion chiller (because it's what I have) and trying to coil it at varying diameters in a spiral...kind of a helix, I guess. I don't think I'll be able to make it as pretty as that SS tube you used. Hopefully the 1/2" copper won't be too big to properly heat the water....I guess I could slow things down so the water spends more time in there. Maybe I'll get some time to do this over the weekend.
 
Don'T kill the immersion chiller because that much tubing is overkill, get 25' of 3/8" copper tube and roll it around 3" plastic pipe to make a coil, then spread coils horizontally to fill pipe. This should work even better than the stainless tube because of better heat transfer with copper tube. After tuning up the design in the stove pipe then sacrifice a corny keg for finished product, or better yet use the corny keg as a heat shield for the 6" inner pipe.
 
As luck would have it, I also have my original IC (25' of 3/8") from when I first got started. I wasn't sure if 25' would be enough...as BP and FSR402 both used 50' of 3/8" copper. What kind of gpm at 180F do you think I can expect with 25'?
 
I was going to go with the stove pipe but I had a keg that was no good so I used that..
If I get some time I think I'm going to uncoil mine and re coil it. The coils right now are so tight to eachother that I can't do much more with it. We will see uncoiling 50' of tube is not going to be a lot of fun.
 
The 25' of 3/8" copper is almost equal in surface area to the 40' of 1/4" SS tube in old boiler, you should be able to hit 1 GPM @180 as the copper is a much better heat conductor than the SS tube. Feed cold water in the top and hot out bottom for best effiency with single tube boiler, bottom up with multiple tube boilers because of dissolved air in water blocking flow with air bubbles in tubes.
 
Man...I bent the tubing without a bender....my hands are frickin sore! I kinked it a couple times on accident, but it all fits. No way could I coil it at 3", more like 4-5. I did my best to cram it all into a 6" stovepipe, and I put a flattened elbow at the top. It looks kinda cool, sorta like a supercharger. I guess I'll try it when I brew on saturday.

On another note, how did you guys cut the bottom off your cornies? I have a jigsaw and a cutoff tool, but I worry about doing it on such a rounded surface.
 
Man...I bent the tubing without a bender....my hands are frickin sore! I kinked it a couple times on accident, but it all fits. No way could I coil it at 3", more like 4-5. I did my best to cram it all into a 6" stovepipe, and I put a flattened elbow at the top. It looks kinda cool, sorta like a supercharger. I guess I'll try it when I brew on saturday.

On another note, how did you guys cut the bottom off your cornies? I have a jigsaw and a cutoff tool, but I worry about doing it on such a rounded surface.

When I rolled mine I rolled it around a 4" pvc pipe and it was easy until I started rolling it back down over the coils.

To cut the keg I used my sawzall with a 12 inch blade.
 
It is easier to wind the tube around the 3-4" pipe, then un bend coils to an oval shape, then adjust angle between ovals to overlap the coils to eliminate the chimney effect. I cheated and used a pipe threading machine to rotate pipe and controlled the coil winding tension by gripping the SS tubing while wearing leather gloves.
 
It is easier to wind the tube around the 3-4" pipe, then un bend coils to an oval shape, then adjust angle between ovals to overlap the coils to eliminate the chimney effect. I cheated and used a pipe threading machine to rotate pipe and controlled the coil winding tension by gripping the SS tubing while wearing leather gloves.

That is soooo cheating..... as punishment I think you should send it to me
 
I suppose I have an unfair advantage in the boiler building area as supervising industrial instrumentation installation projects has side benefits in tools and material leftovers.
 
For the boiler it is a STEC SEC 4500 20 LPM flow, and main burner is a STEC SEC 4550 30 LPM flow. These were purchased on Ebay for about $75 each a couple years ago for use on the phase 2 brewery system. These units require +15V and -15V power and a 0-5VDC control signal. Other manufacturers have units that use a single 24V supply and have similar flow ranges.
 
I can't believe more people aren't doing this in their rigs. There's some obvious kinks to work out, but it's a relatively small unit and it actually has a worthwhile function. I see stirrers, etc. added to rigs, but I'm not sure about the real benefit.

We'll see how my version turns out. I pretty much mangled the tubing, but it looks like it'll still flow. I may eventally end up scrapping it after I work the bugs out and going with 2-4 10 ft sections. I figure 10 feet is probably easier to manage than 25, and then you can just interlace the coils and hook them up to the in/out tees.
 
This has really got me thinking. My problem is my entire set up is electric. I already have an external heat exchanger for my HERMS but it only has about 18' of 1/2 copper in there. I wonder if I use my EHLT and my HERMS heat exchanger in conjunction if I will be able to lower the time it takes to heat my water. I was thinking of having the HLT filled with water and the heating element on and pumping that through the heat exchanger and back to the HLT. I think that it should cut some time off, granted it will not be as fast as the flash boiler but should help.

mike
 
I think the act of recirculating while heating will really make a difference. I plan on doing an experiment and seeing if it's quicker to fill slowly directly from the boiler or to just fill the hlt and recirc while the boiler is heated.

I just had a thought.....if you're a guy like me having problems with the deadspace in the center of the coils, what if you stuck something in there? a 3" piece of ducting with a cap pointing down....to redirect the heat to the sides and out if the center? The heat should come more in contact with the coils that way.....and you could probably turn the burner down too.....
 
The heating time would be the same but you'd be able to regulate the temp more easily.

If you're using tap water input, the only way to regulate the output temp is either flame control (hard to do via automation) or flow control (also not the easiest thing to do). If you fill your HLT and recirc through the flash boiler, you could cut both the gas flow and pump as soon as you reach your desired temp with one simple on/off controller.
 
All very true. In another post, you made the point that inline heating is quicker, i.e. a 0.5 gpm flow rate would heat 5 gals in 10 mins. vs. the 45 mins we see with bulk heating. That seems to make sense to me.

One concern I have is the thermal mass of the water...a small amount of heated water trickling into an unheated keggle is gonna drop in temp quickly. Maybe if you dumped a gallon of hot tap water in first to preheat, you could counteract this.
 
hmmm.......this could be done also with an old gas grill. just put the coil horizontal...


Probably, but there's something to be said for heat rising all the way past the coil in a vertical fashion...like a CFC but in reverse....
 
I think, though, that having a flat grill flash heater that sits on an already useful piece of equipment DESIGNED to keep heat and heat all around the area --- it's like an Alton Brown "multi-tasker" - you can turn off the water then cook burgers, then turn the water back on. :)
 
That's a good point.....for that matter, you could FSR402's original design with the charcoal chimney starter. Install the coil, fill that sucker to the brim with charcoal, and fire it up! Charcoal briquets get up to 800F in some places.....you could definitely heat 10 gallons of water with a full chimney. You could probably still install ducting at the top to address the venting issue. Charcoal's pretty cheap too....you'd probably get at least 5-10 brews out of a $5 bag of the cheap stuff.
 
That's a good point.....for that matter, you could FSR402's original design with the charcoal chimney starter. Install the coil, fill that sucker to the brim with charcoal, and fire it up! Charcoal briquets get up to 800F in some places.....you could definitely heat 10 gallons of water with a full chimney. You could probably still install ducting at the top to address the venting issue. Charcoal's pretty cheap too....you'd probably get at least 5-10 brews out of a $5 bag of the cheap stuff.

That or use the propane grill, then you have hot dogs going on the upper rack while water is heating in the lower rack. :)
 
You could do that, but my concern is that simply laying a coil on the grate isn't as much focused, intense heat as placing it into a chimney with red hot coals or a burner with direct heat. The burner on a propane grill is probably much lower BTU's than a turkey fryer burner, too...
 
All very true. In another post, you made the point that inline heating is quicker, i.e. a 0.5 gpm flow rate would heat 5 gals in 10 mins. vs. the 45 mins we see with bulk heating. That seems to make sense to me.

One concern I have is the thermal mass of the water...a small amount of heated water trickling into an unheated keggle is gonna drop in temp quickly. Maybe if you dumped a gallon of hot tap water in first to preheat, you could counteract this.


That's an easy fix, fire up the burner under the Kettle/HLT just enought to over ride the heat loss.
 
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