In-Sink-Evaporator

[Cedar Eater]

First, let me say that this project was inspired by Fyreaway's e-Vaporator, an evaporator that uses the heating element from a domestic water heater (Edit: Do not use this method. Better options emerged later. Keep reading the thread. -- CE) to boil sap in a custom-designed stainless steel pan. He grabbed the best name for this class of evaporators and his is the best design I've seen. It's more versatile and has a higher capacity than my build. It can be used to make finished syrup and it can reheat syrup for bottling. Due to the shape of his pan, it takes very little liquid to cover the heating element. That's not the case with my repurposed kitchen sink. I'm just hoping my design will boil sap more cheaply than propane.

I started with an old, used, deep, stainless steel, kitchen sink that I picked up beside a road a long time ago, thinking I would eventually add it to my deer camp. It had a sign on it that said "FREE", which happens to be my favorite price. It didn't look as if it had ever contained nuclear waste or anything that came out of a bio-warfare lab, so I plan to just scrub it with whatever it takes to make it look clean and then boil water in it a few times before putting it into service for evaporating sap.

I could have paid somebody to drill the 1-1/4" hole for the heating element in it, but I wanted to do as much as possible on this build and of course, to save money. Stainless steel is hard and difficult to work with. Most cutting tools available from a hardware store are ill suited for working with it. But I knew of two ways to make clean round holes in stainless steel without resorting to expensive special tools, a step bit or a hole saw. If you don't have a drill press available, you will probably want to use a step bit. It's hard to control a hole saw with a handheld drill. Step bits aren't cheap, but I did find one that looks suitable at bargainfittings.com, a popular source for home brewing fittings and tools.

Cheapest 1-1/4" Step Bit I've Found (http://www.bargainfittings.com/index.php?route=product/product&product_id=114)

I have a small drill press, and my plan was to run it very slowly and cool whatever tool I used with oil during the cut, but I had to remove the pedestal and the table from it and mount it at the edge of my workbench in order to get the sink close enough to get the hole as close to the bottom of the sink as I could get it while still drilling through a flat surface. I also had to mount some plywood spacers to the workbench to offset the sink for the bulge for the drain hole. Here's a pic of the drill press setup.

http://i.imgur.com/OM9wDxK.jpg

A new bimetal hole saw is cheaper than a step bit if you already have the arbor for it. I set my drill press to operate at the lowest speed setting, which is 760 RPM. Rather than pushing the spindle down, I used one hand to hold the sink against the workbench and I used my knee to push the sink up against the drill. That left one hand free to deal with cooling the saw. I decided to offset the hole from the center line a bit to make the drain well easier to get a hand into for cleaning after the element is installed. I drilled a 1/8" pilot hole, then used two more larger bits before using a 1/4" bit that matched the pilot bit of the arbor. I got a good clean round hole that only required a little deburring with a round file. I don't think the hole saw is still sharp enough to cut another hole in stainless steel, despite the fact that I cooled it almost continuously with WD40 while drilling the hole, but it did the job. This is the hole before deburring.

http://i.imgur.com/IK1mLjV.jpg


This is the fit of the heating element before deburring. I actually had to screw the element in, but after deburring, it was just a tight fit.

http://i.imgur.com/N7I8ABx.jpg

This is the inside with the heating element in place.

http://i.imgur.com/jNI7nz3.jpg

I can only add four images to a post so I'll continue in the next post.

[Cedar Eater]

Standard heating elements are threaded 1" NPSM, not 1" NPT, so I've ordered a special 1" NPS locknut with an O-ring groove (http://www.bargainfittings.com/index.php?route=product/product&product_id=95) to snug the element against the sink wall. When this arrives, I'll be able to test with 120 VAC.

The next major hurdle with a sink is dealing with the drain hole. Ideally, you want to be able to drain from it using a 1/2" or larger pipe, but it's a huge hole. I could pay someone to weld a plate across and then drill a hole and put a bulkhead fitting through it, but I'm going to try using the drain fitting that came with it. I disassembled it, because it was installed with plumbers putty. I think I can get a food grade sealant after I clean all the old gunk off. There's a food grade red RTV available from Amazon, but I may have to use a large nitril gasket. Here's the funnel section next to the hole it fits through.

http://i.imgur.com/VrkjuiV.jpg

I cut the spokes using ordinary wire cutters. I'll probably have to file the nubs off.

http://i.imgur.com/LuQMjed.jpg

I reassembled the drain with an ordinary steel SAE washer in it. It fit very well. It has the 7/8" hole that would be required to fit a male 1/2" bulkhead fitting. If I can find a stainless steel replacement, I think I can find O-rings and gaskets to get a tight seal. I can test without a working drain, but I will definitely want it working before I boil sap.

http://i.imgur.com/rA2lcLV.jpg

[Fyreaway]

The pictures didn't attach, at least from this computer. I'll try a different machine and see if it's a local problem.

Sounds like you're almost ready to make syrup! The fancy nut with the o-ring groove is the cat's pajamas. The squishy washer that comes with the heating element is good for one fitting. It gets all wonky and you'll never get a good seal the second time. Can't wait to see how you handle the drain. I really like the thought of using a bottom drain. Just bought stock in WD-40 so go drill some more holes.

[Cedar Eater]

The pictures didn't attach, at least from this computer. I'll try a different machine and see if it's a local problem.

Sounds like you're almost ready to make syrup! The fancy nut with the o-ring groove is the cat's pajamas. The squishy washer that comes with the heating element is good for one fitting. It gets all wonky and you'll never get a good seal the second time. Can't wait to see how you handle the drain. I really like the thought of using a bottom drain. Just bought stock in WD-40 so go drill some more holes.

I needed to edit the links to imgur to get the photos to show. I won't be making syrup in it for a while, but hopefully I'll be boiling water soon.

[Fyreaway]

Got the pics and she looks great. The bulkhead fitting should be an easy find and a nice solution.

[Cedar Eater]

I ordered a 1/2" MNPT bulkhead fitting (http://www.homebrewing.org/SS-Hex-Nut-Weldless-Bulkhead-12-MPT-_p_5020.html) last night. With any luck, the SS washer that comes with this fitting will fit the drain assembly. I'm looking for cheap 1/2" SS full port ball valves now.

[Fyreaway]

The bulkhead fitting looks really nice. The low profile on the wet side of the sink will give almost a total drain.

[67HEAVEN]

Loving this stuff. Keep it coming.

It's great to be looking at this now and not at the beginning of the next sap season.

[Cedar Eater]

The bulkhead fitting looks really nice. The low profile on the wet side of the sink will give almost a total drain.

That was my thinking. there was another one with a coupling that stood up about an inch and could have a strainer of some sort threaded into it, which I'm guessing is for draining wort, but this one seems ideal for a liquid that isn't chunky.

[Cedar Eater]

Loving this stuff. Keep it coming.

It's great to be looking at this now and not at the beginning of the next sap season.

Thanks. I like your idea of finding a kitchen sink cabinet, but I'm picturing leaving this out on my deck, next to the gas grill. So I might build a frame from pressure treated deck boards. I might also put a faucet in with a garden hose connection for washing and maybe doing some boiling of corn or potatoes while grilling. I would probably need to have a SS heat shield to keep food from touching the element, but that doesn't seem too challenging.

I found this for anyone who wants a ready-made e-Vaporator on a smaller scale.

Condensate Evaporator Pan - 15 Quart 240 VAC (http://www.globalindustrial.com/p/hvac/service/maintenance-tools/supco-commerial-condensate-evaporator-pan-15-quart-240-volt)

There are smaller 120 VAC models also.

[paulrich]

good info can be found on Heat Source Comparison including electric http://www.kegkits.com/heat_sources.htm

[paulrich]

From that site I found this interesting info

BTUs from 120V or 240V Electric

Everything changes with electricity. When you use a submerged electric element your heat source is 100% surrounded by your wurt and the only heat that escapes is the heat that is radiating through the sides of your pot & escaping through the top. This means that almost 100% of the energy you put into your electric element gets transferred to your wurt. And at an overall efficiency is 90% or better, you will need 24,639 BTUs from electricity.

One watt of electricity = 3.41 BTU/hr, so 24,639 BTUs will require approximately 7225 total watt/hrs. Actual cost to you depends on your local utility rate but at North Alabama’s current rate of $0.08416 per KWh and adding 25% more electricity for mash & sparge, and the electricity cost of brewing a 10 gallon batch will be about $0.75.

[paulrich]

Do check the other info interesting info that can be used.

Electric Brewing
Heat Source Comparison
About BTUs
Boil Control
Mash Control
Sizing Wires
Wiring Diagrams
Calculating BTUs
Brewery Wiring
FOTEK SSRs
Temperature
Sensors

[Cedar Eater]

The special locknut and the 1/2" bulkhead fitting arrived today. Unfortunately, the washer on the bulkhead fitting isn't large enough to do what I want. It looks like I'll have to get a washer that's close but oversized and then modify it to fit. I boiled 16 gallons of birch sap down in the Kenmore Sugar Dryer today so at least I got that much accomplished.

[saphound]

I found this for anyone who wants a ready-made e-Vaporator on a smaller scale.

Condensate Evaporator Pan - 15 Quart 240 VAC (http://www.globalindustrial.com/p/hvac/service/maintenance-tools/supco-commerial-condensate-evaporator-pan-15-quart-240-volt)

There are smaller 120 VAC models also.

Man, that would be perfect if it were about twice that size. I wonder if this company realizes their evaporator pans could have a maple sap application. I bet a deeper 30qt model with a draw off valve would be a big seller. I'd buy one right now. Maybe someone should tell them.

[Cedar Eater]

In case anyone is thinking of attempting to make a sink-based evaporator, I can report that I found a stainless steel flat washer that I think will work at the bottom of the drain. It was sized for a 3/4" bolt. Washers are typically about 1/16" oversized for the bolts they are made for. This one had a .812" hole diameter (ID) and a 1.75" OD which fit well in the collar of the drain well. The washer ID had to be increased for the 1/2" NPT bulkhead fitting, which has a diameter of 27/32" (.840"). I went old school with a round file (bastard cut) for about 1/2 hour to get the fit that I wanted. This washer has to contact the O-ring, so a 7/8" hole might have been too big. I also used Red RTV for sealing the drain well through the 3-1/2" drain hole in the sink. It has to set for 24 hours, so I won't be testing until the day after tomorrow. I have a neoprene gasket at the bottom of the drain well to seal the washer to the funnel section. That might not be able to take the heat, so I'll be prepared for a leak there. I've got 1/2" 304 SS full port ball valve ordered from Amazon for less than $8 plus shipping. I can test before that gets here by just capping the bulkhead fitting.

[Fyreaway]

CE,
I assume your sink will be mounted to a stand of some sort. Will you run the drain straight down or give it a turn to make access easier? One thing I learned was to put the valve at the very end of the drain. It's no fun having to lick the syrup off the floor when it drips.

[Cedar Eater]

CE,
I assume your sink will be mounted to a stand of some sort. Will you run the drain straight down or give it a turn to make access easier? One thing I learned was to put the valve at the very end of the drain. It's no fun having to lick the syrup off the floor when it drips.

I'm planning to put it on a high stand with room to slide a pot for finishing right underneath to pour into. The valve will be vertical, very close to the drain. I'm tall and having it up high works better for me.

[Cedar Eater]

I guess I jumped the gun by using a water heater element. I could have made it cheaper by looking at spa components. They work in everything from strong acid to strong base and they install through small holes in flat surfaces. Here's an example.

Spa Heater Element. (http://www.spadepot.com/shop/Universal-Flo-Thru-Spa-Heater-Element-10-P803C707.aspx)

[67HEAVEN]

They work in everything from strong acid to strong base...

I confess to not understanding what strong base is.

[Fyreaway]

That's pretty neat. The only other heater I considered was from a dishwasher. That flow-through tube housing would work as an inline preheater too. Nice find!

[Cedar Eater]

I confess to not understanding what strong base is.

Highly alkaline, high pH, opposite of acidic (low pH), caustic.

[Cedar Eater]

That's pretty neat. The only other heater I considered was from a dishwasher. That flow-through tube housing would work as an inline preheater too. Nice find!

I think I might get one of these and put it through the bottom of my sink, then run both elements with opposite legs from the 240V feed as an intermediate wattage between either element at 120V and either at 240V. That way I can have an element down lower in the sink.

[Cedar Eater]

I was talking with some family members about this project and I learned that one of my cousins is a materials engineer and that he welds stainless steel, so I broke my rule about not getting professional help. I talked with him about this project and he convinced me that it would be safer to weld than to rely on RTV gaskets for the drain of the sink. So I took the job to him. He thinks that the sink is probably only 24 guage, but he welded the entire funnel section to the bottom of the sink and he welded the washer across the bottom of the funnel. The heat warped the sink's floor a little, and he said it was his first experience welding stainless that was that thin. But he managed to get a tight seal and he worked for syrup, so I'm very happy with the result.

http://i.imgur.com/LGEtOr1.jpg

I brought it home, installed the bulkhead fitting, leak tested it (it passed), installed the heating element, finished filling the sink with hot water, and plugged it in to a 120 VAC receptacle. There's currently about 8 gallons in the sink. The temp slowly rose up over a period of two hours to 161 degrees and just doesn't seem to want to get higher. I have my doubts that adding insulation will get the temp up to boiling temp, so I will have to add more heat. The easiest way will be to get the voltage up to 240 VAC, but I also ordered a spa heater element to install in the sink. It will make the sink that much more useful., because the new element will be much closer to the floor and will require less sap to immerse it. My plan is to selectively switch the elements on and to change their voltage by flipping switches. I will then have watt options of 1125, 1375, 2500, 4500, 5500, 5875, 6625, and 10,000, but the feeder circuit will not be able to feed both elements for long if either or both are at 240V.

[bkeith]

All this talk of immersed elements made me think: Why not repurpose a deep fryer, either domestic counter top, or larger commercial unit?

New thread, go!

[Cedar Eater]

All this talk of immersed elements made me think: Why not repurpose a deep fryer, either domestic counter top, or larger commercial unit?

New thread, go!

I personally haven't seen a countertop unit with a huge surface area. Evaporation rate is proportional to surface area. A larger commercial unit would be expensive. On top of that, having the element in direct contact with the liquid is more efficient, but having an element in direct contact with fats and oils results in coking, so I've never seen a food unit that had direct contact with the element.

[bkeith]

Many home units use immersed elements now. Commercial units have for a long time.

True, surface area isn't great, but it would be a convenient way to do small batches, or use as a finisher.

http://www.walmart.com/ip/Deep-Fryer-Electric-2500-Watt-Commercial-Unit-Restaurant-Frying-Deep-Fryer-New/29603407

[Cedar Eater]

Many home units use immersed elements now. Commercial units have for a long time.

True, surface area isn't great, but it would be a convenient way to do small batches, or use as a finisher.

http://www.walmart.com/ip/Deep-Fryer-Electric-2500-Watt-Commercial-Unit-Restaurant-Frying-Deep-Fryer-New/29603407

That's pretty cool. I guess I hadn't seen any modern deep fat fryers. That has a low watt density element to keep from coking up (the length of the element is a giveaway), and it looks like it would make a good finisher. I was also thinking of using a half size or smaller steam table pan with a spa element. That could have a drain valve in the bottom.

[Cedar Eater]

I'm rewiring the spa disconnect to provide power to my back deck for the sink and for an electric stove that I'm going to use as a smoker, so I'm waiting on parts rather than just kluging in a connection to the sink, but I did manage to build a stand for the sink.

http://i.imgur.com/d43ceGh.jpg

[Cedar Eater]

I think I found the exact model of the sink I'm using and I haven't seen a cheaper SS sink in this size class. It's less than $60 without a drain fitting and it ships free from Zoro. It's the Elkay K125224 (https://www.zoro.com/elkay-drop-in-sink-25-in-l-k125224/i/G8634762/).

If you don't want to weld a plate across the drain opening, Amazon has food grade high temperature Red RTV sealant that should work fine for this drain fitting (http://www.amazon.com/Moen-22036-Composite-Assembly-Stainless/dp/B0012C52RQ/ref=pd_sim_hi_3?ie=UTF8&refRID=0XYY46XM557Y12HE8HJ7).

[Cedar Eater]

I added a 5500 Watt spa heater element to my sink, filled the sink right to the top (>8 gallons) powered up the element with 240 VAC and in about an hour, I had this

http://i.imgur.com/TW1GdmO.jpg

It's a rolling boil right above the element. During the installation of the element, I made the mistake of not offsetting the holes far enough to keep the element from touching the wall. The terminals for the element are not centered, so the holes for them have to be offset. It only just barely touches in the curved part at the bottom of the wall, so it will cost me a little of the efficiency as the element directly heats the sink, but SS is a really poor conductor of heat, so I decided not to bother plugging the hole and moving the element over. If there's ever a Sink II, it will be better.

The holes for the teminals are 1/2" and they are spaced 1-1/4" apart. Precision on the spacing is important, because the element is very rigid in that dimension. Not exceeding the 1/2" hole size is also important, because the elements have an o-ring seal. I started by drilling 1/8" holes in the bottom of the sink and that was the hardest part of the drilling. Once those two holes were through, it was easy to increase the hole size using only ordinary titanium drill bits.

The spa heater element is a much better option than the water heater element. It only took two gallons of water to immerse the spa heater element, whereas it took more than four to fully immerse the water heater element, because that had to be mounted on the wall above the curve. I would not use a water heater element in Sink II.

I think the titanium elements might be a better option than the stainless steel elements. I might add one to compare them to the stainless steel equivalent. They cost more, but they should have a longer life. I'm interested in keeping the surface temp of the elements down to minimize caramelization on the element. I had considered using two elements and switching them to 120V as soon as possible, but I did an experiment with an infinity switch from an electric range. That's the typical twist type switch that usually has a minimum keep warm setting and a scale from low to high, or 1 to 6. They are 240V switches, but they cycle on and off, which has the effect of giving an average current that's lower than the current of a straight connection and would heat the element and the wiring less.

I haven't been able to find an infinite switch that can pass more than 15 Amps. I tried a switch that was rated at 11.5 Amps, which would mean it was feeding 2760 watts. It brought the water temp up to 180 degF. I added another 1125 Watts from the water heater element and that brought the steady state temp up to 200. Amazon sells a universal 15A replacement switch that would pass 3600 watts. If 3600 is enough, running a 5500 watt element at 3600 average would cut down on the skin temp of the element. I think I'll try one.

[Fyreaway]

Now that's a really nice build. The spa heater was a great find. The longer element should help a lot with the sugars burning on. I found that running a 4500 watt element at about 3600 watts would keep up to 5 gallons boiling steady. It would be nice to get the full pan boiling as fast as possible but it's more important to be able to hold that temp until it's time for pancakes. I think you're really going to like needing only 2 gallons to cover the element and get the heat going. If you can control the sap addition you might find that keeping the level lower will use less energy to keep a good boil.

[Cedar Eater]

Thanks. Now that I've got this one, I'm thinking of using what I've learned to make the cheapest electric evaporator I can. One 6" deep full size steam table pan, one 5500W spa heater element and one 15A infinite range switch will produce a 3600W eevaporator with about 1.5 sqft of surface area. Due to the smaller footprint, it would take even less to immerse the element. I think I can get the total under $90. Maybe even under $80. Anybody who already has the steam table pan might be able to do a conversion for less than $60. It wouldn't take many gallons to pay that off vs. propane. Three of those could be fed from a 50A welder, pool , or spa circuit and would have about 4.5 sqft of surface area. Two of those would have 50% more surface area than your e-Vaporator design or my sink, and they could be fed with a 30A RV hookup circuit. One could be fed with an extension cord from an electric dryer circuit. They wouldn't be as convenient, but there's always something to be said for cheap.

Edit: The infinite switch turned out to be a bad idea and the 5500W element was too much for the steam table pan. I dropped it to a 4000W element and controlled it with a simple 2-pole on-off switch. I documented the design in the DIY Electrical Evaporator Design (http://mapletrader.com/community/showthread.php?26094-DIY-Electrical-Evaporator-Design-Page-1) thread. I would only feed two of these from a 50A circuit. It looks they will have an evap rate of about 1.5 gph, but I haven't done a real world test with sap in March-April conditions yet.

[Cedar Eater]

I wired a 10 kW PWM controller that I got for under $20 from eBay in to the 5500W element. I'm waiting on 2 pole 30A switches for each element (and sap of course). I hope to use this one pretty soon.

[Cedar Eater]

I boiled sap in the kitchen sink for the first time last night. It was a roiling success. I'm getting almost 3 gph using only the 5500W spa element. I started with five gallons of cold sap and both elements switched on. Within five minutes I had vapor rising off the sap surface. In the fourth photo you can see the foam initially gathering above the elements. Within 15 minutes I had a rolling boil. I turned the long water heater element off to keep it from becoming exposed and only used the spa element after that. This tells me that I could run two sinks of this size on one 50A 240V circuit and achieve a 5+ gph boil rate. This sink combined with my electrified steam table pan will give me a roughly 4 gph boil rate. I'm planning to use a fan blowing across these surfaces to boost the boil rate and decrease the condensation on the metal awning roof that now covers my deck.

1364313640136381364113642

[Cedar Eater]

I removed the controller from the circuit for the 5500W heating element so I could use it for a smoker. The 5500W element is so well behaved that the controller was pointless. I now just switch the element with a 2-pole 30A switch.