I made another RIMS in 2000 and have hacked on it since then.  A lot of changes in design were made, but the basic principles are the same as those detailed on this page.  If your already familiar with this page, skip to the  Current RIMs Page.
 

The wort exit fitting is soldered together from 1/2" copper pipe fittings. Here's a drawing of the wort exit fitting.

The sight gauge is attached to the tun with a bulkhead fitting cobbled together from 1/4" copper tubing fittings. The assembly is very similiar in design to that used on the tun outlet (details above). 1/4" copper tubing attaches the bulkhead fitting to 3/16" ID vinyl tubing which is the actual sight gauge. The vinyl tubing is supported by a portion of the RIMS stand. Also connected to the copper tubing is a "solid-state" liquid level transducer which I hope to interface with the system controller so that pump speed is automatically controlled.

The current RIMS uses a manifold made from the outer stainless steel sheath of tubing intended for connecting plumbing fixtures to piping. Two 60" sections were used. One end of each section connects to the 1/2" copper tee in the bottom of the tun via 1/2"x3/8" copper solder type adapters (the 1/2" end is a male type- it inserts into the tee). They are NOT soldered to the tee, therefore, the manifold can be removed easily for cleaning. The sheathing ends go over the 3/8" adapter ends now on the tee and were fastened to them via wrapping with 22 AWG stainless wire. Now for the hard to describe part- how to fit 10' of sheathing into the bottom of the RIMS tun (I'd furnish a drawing but my CAD program doesn't do spirals...). One of the pieces of the sheathing is fashioned into a loose spiral (leave a space between each revolution of the spiral). The other is fashioned into a similiar spiral that lies between the revolutions of the first spiral. Picture a yen-yang thingee with the arms continuing to sprial outward. To hold the manifold into this shape, I used stuck 4 pieces of stainless steel wire laterally through the manifold. The manifold works great. It allows a better flow than the old false bottom. There's only about 1/2" of friction loss at a flow of 3/4 GPM with a 8# pale ale mash. It's also very easy to construct.

The heater chamber is made along typical RIMS lines with 1-1/2" diameter Cu pipe and fittings. Finding someone to sell a short lenght of the 1-1/2" pipe was the most difficult part of making the RIMS! This ain't a hardware store item- look in your area for a plumbing supply house- the place plumbers buy thier stuff.

The only real departure from the typical chamber is the incorporation of a 1/4" needle type valve at the very bottom of the chamber. I've noticed that even with 2-3 hot water flushes after mashing a batch, brown crud material collects in this portion of the chamber between uses. The valve allows all of the water to be drained since this point is the low point in my system. At the business end of the heater chamber is 1.5" x 0.5" x 1.5" copper solder type tee. The end the heater fits into was cut off so that only about 1/2" remained- this gets the wort-in pipe closer to the bottom of the heater to help ensure there's flow at this portion of the heater. Into this end a 1.5" male solder x 1" female copper female threaded adpater is soldered. The soldered end was cut off a bit to match the lenght of the end of the tee. The aforemetioned drain valve has compression end fittings and is fitted to this portion of the heater chamber with via a 3/4" long piece of copper tubing that's soldered to a hole drilled in this part of the tee. Locating this hole by eye-balling where the base of the heater element will be and drilling a 1/4" hole just above that point.

The heating element is 240 VAC, 4500 W, 16-3/8" long low watt density hot water heater element ($11.89 from Johnstone Supply Stock #N87-129). Whatever you use has gotta be of the "low watt density" type to avoid scorching of your wort. Picture a long U that's folded-back on itself (if you cut it transversly though it's center, you'd see 4 pieces of heater element). A gasket that comes with the heater fits between the element and the end of the chamber- do NOT depend on the thread engagement to make a leak-tight seal! The heater is a just a bit difficult to screw into the end of the chamber since, although both are 1" diameter, the adapter is pipe (i.e. taper) threaded while the heater element is straight threaded. Use a bit of care to avoid cross-threading. I used teflon tape applied to the heater threads- it's used to lubricate the joint for fitting-up and not for making it leak-tight!

<--- Drawing
I hope the drawing is pretty self-explatory 'cause I tired of typing... . I used the stirrer for mashing-in and as needed for unsticking a stuck bed since RIMS ver. 5 "evolved" before I had a chance to try running it constantly during the mash and otherwise playing around with it...

I used a ice cream freezer motor (something like 30-60 PRMs). It would not stir a stuck mash, so I made the motor removable so a crank could be attached. Took at least 20 ft.-lbs. of torque to start the stirrer turning with a stuck bed! Maybe a shallower pitch on the blades would help... My choice for power would be a DC gearmotor. That way you can easy change the RPMs (via a variable voltage power supply or a simple PWM circuit) to get optimum stirring. For an AC gearmotor, choose one with a universal type motor so a reqular lamp dimmer can be used to vary the RPMs. Oh yeah, the couplings that are soldered to the blades have vertical kerfs sawn in them so that each blade can be secured to the shaft by tightening the hose clamp that goes over the kerfed portion of the coupling. This allows you to add and remove blades as well as adjust their spacing. 

The controller is my own design. A schematic appears below. It's brain is a $49 Basic Stamp II made by the fantastic folks at Parallax Inc. This gizmo is real computer on a 24 pin IC! Really! It's connected it to a PC via a serial port and programed and debugged in Basic. Once programmed, it can be disconnected from the PC. It has 16 i/o lines can be configured via the programming to do all sorts of amazing things like serial i/o for talking to other Stamps, PCs or other chips, reading resistances, counting pulses or measuring their width, generating DTMF for dialing phones, controlling X-10 wireless Radio Shack 120VAC control modules, pulse width modulation, ect. An amazing device!!!

<--- Controller Schematic 

More Controller Info

• Two conductor sheilded twisted cable is used for connecting the thermistors to the STAMP.  I've since switched to zip cord- fancy cable isn't needed.
• I used MOC3031 opto-isolators. They have a zero-crossing feature which I feel is important in reducing EM interference problems and also reducing the heat dissipated.
• The triacs are Teccor 400V, 15A isolated type, available from Digi-Key as part no. Q4015L5-ND for $2.61 (as of 9/96). They also have the MOC3031 opto-isolator.
• I mounted the controller in 3 enclosures. There's a 4"x4" gang box which holds 2 duplex receptacles. Two outlets are controlled by the triacs- the RIMS and sparge water tank heaters are plugged into these outlets. The other 2 are just wired to the 12 ga., 3 conductor flexible cord that supplies power to the RIMS. The heatsink onto which the triacs are mounted is fastened to this box. Aside the 4x4 box, I have a box which holds the optocouplers and a small 5 VDC linear power supply for the controller. The box also includes jacks for the 3 thermistor cables and a DB-9 socket. The foregoing boxes are screwed to the RIMS' frame. The remainder of the circuit components are in a 4x6" plastic box that's attached to the DB-9 socket via a 8' or so piece of sheilded 9 conductor cable. This allows me to place the controller beside a chair for easy monitoring. If you want to try a different mounting arrangment, take steps to ensure the EMF and spikes the triacs generate don't interference- i.e. scrambling of the STAMPS's brain and such.
• Use a 120VAC circuit protected by a GFCI. Having a GFCI doesn't eliminate the need for grounding tho'! Every piece of exposed metal needs to be well grounded. I wrapped and soldered some 12 ga. copper wires onto the RIMS plumbing for this purpose. Soldering isn't a "code approved" method tho'. A grounding cable clamp would be more acceptable.
• I power my system via a 120 VAC, 20 amp. circuit. With 4.5kW, 240 VAC rated heating elements the average current is about 9.5A. A 15A circuit should work if there's no other big loads on the circuit.
• Mount the triacs onto heat sink(s). The heat sink I used is grossly oversized (2x4x1/2" and about 6 oz. or so). The heat sink is just barely above ambinent temperature during operation.
• Stamp i/o pin 15 is used for connection to a PC serial port. I've since found out that the programming port (Stamp pins 1-4) can be used for this function also with a bit of wire swapping. This frees up i/o pin 15 for another use. In addition, since this port is bidirectional, one can use the PC it's connected to as the operator interface and brains for the system.
• I used the handy Maxim MAX232 RS-232 chip and 50' of 2 conductor, 22 ga. zip-cord to tie the Stamp to a PC. I've another Stamp project which transmits data to a PC reliabily over 30' of ordinary phone wire without the MAX232 but, YMMV! On a related note, the Stamp doesn't output "real" RS-232 levels and some Stamp users have reported problems getting their Stamps to talk to some models of portable PCs even with short serial cables. There are some fixes for this problem I'm told. The MAX232 chip would surely be one fix. Desktop PCs are reportly immune to this problem.

The display shows the temperature at both RIMS thermistors, the RIMS set point, the elapsed time and the on/off status of both of the heaters. The temperature of the water in the hot water tank and it's set point can be displayed via pressing one of the keys. The set points for both the RIMS and hot water tank can be changed at any time via the key pad. When the set point is changed, the controller asks if the elapsed time should be reset (that's what the Dallas DS1302 real time clock chip is for). Until I incorporated a timer, I often forgot to keep track of rest times. This function is also available separately via the key pad is is handy for timing sparges as such. The piezo element doesn't do much at this point- it just emits soft beeps indicating when the heaters are on- different beeps for the two heaters. Since the STAMP is programmable, it's possible to program the entire mash schedule and let the controller take it from there. As the textbooks say, this is left as an exercise for the student :-).

The controller also includes an optional serial transmit only link to a PC with the PC acting soley as a data logger. I've written a simple little program for the PC that captures the data stream and writes it to a file for later analysis (holler if you want a copy). Some of the resulting time/temp graphs appear below. The data was imported into 123, distilled to 1 sample/sec. from the 2-3 samples/second in the raw data and graphed. Both mashes were done with the heater programmed to turn off with a wort temp. > 2 degF above the setpoint and a flow of abour 0.5 GPM. You'll note that the temperature at the heater discharge continues to rise for another 2-3 seconds after the heater power is killed before peaking at 5 degF or so above the setpoint then pretty dropping rapidly. These peaks are much higher with lower wort flows- another good reason for making the best false bottom you can. OTOH, one could use a proporational or PID control algorithim rather than the simple "bang-bang" one I used...

For those of you who want a simpler electronic thermometer or controller, Ken Schwartz has written a very nice page here.

Here's the main piece of the Stamp programming.

This is the other, supporting piece of the programming.

<--- A complete mash cycle

The grain bill for the above mash was 8# of pale ale malt, 1/2 # flaked barley, 1# crystal malt and 2 oz. of black malt. Yeild was 31 p/pt/gal. Below is a detailed graph which better shows the controller's performance:

<--- Detail graph

Vent Pipe An old HomeBrew Digest post recommended putting a vent pipe at the top of the false bottom. Do NOT do this! The pump will suck air big time! As Rick Calley (web site) said, about the best use for them is as a handle for removing the false bottom. OK, air vent(s) (which you open after filling the RIMS with water and close before starting the pump) may be required if you've not done as I've told ya and have trapped air pockets in the pump suction line- air pockets in this section of the plumbing are a "bad thing" and should be eliminated by proper arangement of the piping and not compensated for with air vents.

False Bottoms A phil's phase bottom (which phloats!) does not work with the pump I use- it caused way too much flow restriction. Dion (web site) uses one, but his system uses a "real" RIMS pump. I ran an experiment with a previous incarnation of my system to determine where most of the friction loss on the suction side of the pump takes place. I had a sight gauge attached to the piping between the tun and pump and to the tun just above the old false bottom (now replaced with a manifold) and ran a mash (7# of pale ale malt and a bit of roasted barley) noting the difference in levels (i.e. pressure) between that gauge and the one in the pump suction piping. Most of the loss was in the grain bed- 8" there and another 2" in the false bottom and piping (all 1/2" copper) to the point where the lower sight guage attaches. Almost all of the later loss is in the false bottom/grain bed interface since the flow was only about ~1/2 GPM. A similar mash with the new manifold had only a 1/2" pressure drop in the manifold and piping and a higher flow rate (about 3/4 GPM).

Pump Suction Piping Do NOT use tubing which becomes soft at mashing temperatures between the tun outlet and the suction side of the pump! My first try used pretty heavy wall 3/8" ID vinyl tubing (disk sink sprayer hose) which rather promptly collapsed completly shut. Since this was with a phil's phalse bottom and it's big pressure drop, the pump sucked the tubing closed rather promptly and tightly!

Stoppers I use rubber stoppers for mounting the thermistors in the plumbing. Do not try to fill the system without the one in the suction piping inserted or operate the pump without the other one inserted (DUH!). Yeah, I've done each of these bone-headed things!

HeatersDo NOT operate the heaters without fluid (duh!). If you use alot of sparge water, it's quite easy to do with the heater in the HTL. Consider putting in a level switch affair which'll cutout the heater at a low water level. Do NOT operate the RIMS heater without flow through the heater chamber for it'll reportly rather promptly scorch and perhaps even boil the wort in the heater chamber. If you are the type that's sometimes forgetful, consider electronically interlocking the heater with the pump. Unlike my misadventure with the rubber stoppers, I've not done either of these things- yet...

Cleaning Run at least a batch of hot water through the system as a flush immediately after mashing. I flush twice, once with tap water then recirc with a gallon or so of 168 degF water for ~5 minutes. Flush out the water via the recirc hose then drain well while the system is still hot and leave all the valves open to allow a bit of air to circulate. When system cools, close valves and otherwise seal up the system. Before using, I recirc. a gallon or so of warm tap water for ~5 minutes and sometimes bring it up to 168 degF or so. In the 20 or so batches so far- the 3 times I've pulled the heater for inspection I've not noted a crud buildup problem on the heater element as others have reported. I think trying to maximize the recirc. flow, using a long low watt density element and using the heating element control stragety I use have alot to do with this.

To be continued I'm sure there are lessons I've forgotten and others I've yet to learn...

The forgoing details the way the first (circa '97) RIMS evolved up unti 2000 when I built another RIMS.  As of 2/02, it's kinda like the one detailed on this page except for the following:

• The tuns is a Rubbermaid 50 qt. rectangular picnic cooler.  The recirc flow has increased dramatically due, I think, to the much shallower grain bed relative to the old plastic pail tun.  Kinda surprisingly, there was no detectable loss of efficiency.
• It has a slotted copper manifold instead of one made from SS mesh.  I much perfer the mesh but I found it very difficult to mount and secure in the bottom of the tun.  I tried wiring it down to plastic needle point mesh, but the thing wouldn't lie flat on the bottom of the cooler (the mesh isn't stiff enough).  Plus it just plain looked bad.
• The return manifold can be adjusted in height in the same manner, but the manifold is a single, straight  peice of 1/2" copper pipe with holes drilled in it's side so the wort is directed across the top of the grain bed.
• It uses a March MDX-3 pump from  Moving Brews (a great outfit!).  I sure miss the old RIMS's 12VDC pump since speed control was a breeze.  The speed of the March pump apparently can't be speed controlled- I've tried a ceiling fan speed controller, a dimmer and even a variable transformer- even the later gave terrible performance.
• There's no stirrer (a round peg in a rectangular hole....)   I miss the stirrer!
• The heater chamber is mounted with it's terminal end up.  This eliminated the need for the funky.stupid drain valve I used on the one detailed on this page.  Also, the heater is screwed into the chamber via a 1" hose thread fitting soldered to a drilled-out end cap atop the 1.5" pipe.  I like this better since the hose threads are straight- just like those on the heater element.
• Changed the controller schematic and programming so that I/O pin 15 is free (it had been used for sending mash data to a connected PC via a 2 wire serial connection). The new serial link is 2 way and uses the programming port (physical pins 1-4 on the Stamp). I've dispensed with the Maxim RS232 driver with great results- communications are excellent at 1200 baud over 100' of cheap flat type telephone cable.
• I now use one of Scott Edwards serial LCD "BackPacks" instead of the parallel interface on detailed on this page.   This frees up several I/O pins (which I've not used yet...) and, more importantly, it greatly simplifes programming and resulted in smaller a program, so I...
• Added a function to the controller program which allows the dT to be changed "dynamically" via the keys on the controller.  (The dT is the difference between the setpoint and the temp. at the thermistor located downstream of the heater- if the programmed dT is exceeded, the controller cuts the heater off).Kinda useless for me tho' since the old 2 degF dT gives good results with no worries of scorching or denaturing the enzymes.
• I've run a scond 120 VAC circuit so the program was changed to allow the RIMS and HLT tank heaters to be on at the same time.
• Added DPDT switches to provide Hand-Off-Auto control for the heating elments in addition to...
• Added a controller funtion which allows the heaters to be turnned on/off via sone keystrokes thereby passing the automatic control.  The program makes the beeper emit a terrible noise so I won't forget!

Future Improvements

If you've read this far, you might have forgotten I'm now using a different RIMS.  In that case, recheck the Needed Revisions section above for what's changed.

I'd like to add to the programming by extending the temperature range. If the temperature is below 125 degF, the controller treats it as 255 degF and you have to manually control the heaters by plugging them into one of the receptacles without triac control until the temp. is >= 125 degF.

Another BIG improvement is the addition of some hard and software to automatically control the level of water in the tun during sparging and to automatically control the RIMS pump speed based on the level of wort in the sight gauge.

Use an old PC for the "brians". The system will still a the Stamp, but only as a interface to the RIMS.  I like this 'cause I could keep my brewing notes/log on the PC rather than on scraps of paper.   At least that's the theory!

Credits/Links
There's an old saw about standing on the shoulders of others who've gone before you... here's some of the very kind fellow homebrewers who've shouldered the previous work in RIMS design. I'm deeply indebted to them!

• Rodney Morris- the inventor of RIMS!
• Dion Hollenbeck- author of a forthcoming RIMS book. ( web site)
• Rick Calley- a great gadeteer! (web site)
• Ken Schwartz- THE electrified brewing expert! (web site)
• Keith Royster I had a lot of help from Keith! (web site)

Emile van de Logt- a great HERMS system

Legal Mumbo-Jumbo:
Use any and all of the above for your own use for FREE! Use the stuff and make money with it and I want some of the $$$! Use any and all of the above at your own risk. It works for me but may not for you, i.e. YMMV.