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.
<--- Drawing
of the heater chamber
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!
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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.
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Block Diagram
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!!!
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Schematic
More Controller Info
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:
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. It is detailed on here.
Add code to the programming to extend the temperature range. If the mash or HLT 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.
Add 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. The homebrewed solid state liquid level transducer would be a good way to start.
Use an old PC for the "brains". Retain the Stamp, but use it only as an interface to the transducers and triacs. I like this 'cause I could keep my brewing notes/log on the PC rather than on scraps of paper.
Return to my Main Page
c.d. pritchard,
r?, 10/05
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