Rebuilding a pair of 2 group Lineas adding pressure profiling

by **Rosscopico0** on Wed Dec 09, 2009 3:38 pm

Hi all,
Im new here.
I have been a barista for a few years but have a background in electronics & fiber optics. I also like to tinker....

I have bought both of Todd's 2 group Lineas & will be doing the rest of the rebuild, as well as a few mods. Here is the link to his thread La Marzocco Find...What have I gotten into!

So Im going to rebuild them one at a time. While Im at it, I figure I might as well do a few mods.
I'll be doing the PID upgrade first.
Im thinking I will also insulate the boilers as well for greater thermal efficiency. Anyone know if this will cause problems with the PID unit?

Im thinking that since the machines dont have pumps, I might as well get myself a TMFR pump & controller & be done with it. Any ideas how much these cost?

http://users.rcn.com/erics/ · by **erics** on Wed Dec 09, 2009 4:12 pm

Any ideas how much these cost?

The TMFR Pump/Motor and Drive are about $300. But to that you need to add in:

Properly configured Fuji PXG4 Controller ~ 269
Pressure Transducer ~ 155
Regulated Power Supply ~ 44
Project Box ~ ?
Miscellaneous Wire, Terminal Strips, Connectors ~ ?
Blood, Sweat, Tears ~ ?

It "ain't" inexpensive BUT see this for a somewhat less expensive but still very effective and neat manual control setup:

'Pressure Profiling' With The Fluid-O-Tech TMFR Pump - Or, Wholesale Copying Greg Scace's Ideas

by **Rosscopico0** on Wed Dec 09, 2009 11:03 pm

Hi Erics, Thanks for your reply.

This will be a test subject for me, if it goes well, Ill implement the changes in the FB/70 3 group at work.
I want the repeatable aspect for a busy cafe.
Also I eventually want to do a 4 group Linea with separate temps & profiles on each brew boiler, for a guest SO espresso as well as the staple Blackcat.

I would love a pair of Chronos keypads, not a fan of the AV keypads. Prefer manual controls but I like the integrated timer.
Want to put in some barista lights & maybe a reflective strip a la the Slayer machine.
I hate the standard steam knobs, thinking of making an Synesso style side lever.

Thinking of using pressure & temp sensors very close to the groupheads & using the internal flowmeter (I suspect it just sends pulses, but not sure).
For now Im thinking of using a few programmable analog input units to record & display data (temp, pressure & flow rate) on my netbook.
I can also use a programmable analog output unit to feed S-curves with adjustable curves & trapezoidal ramps with programmable ramp rates to the input of the pump motor controller. Then its a scace II device to calibrate my system.
I would also like to use an output from the brew PID module so that I can compensate for any small margin of error from brew boiler temp to head temp.
Once thats done & working well, Ill do a microprocessor with enough memory to save a few hundred profiles, a dot matrix display & a serial interface for tuning & dumping data

by **Rosscopico0** on Thu Dec 10, 2009 7:09 pm

Can anyone tell me what the output signal of the Lineas flow meter is?

Is it a pulse or varying voltage?

by **pdx** on Thu Dec 10, 2009 7:50 pm

Why use a tmfr pump instead of a gear pump?

by **Rosscopico0** on Thu Dec 10, 2009 10:11 pm

Pls enlighten me on gear pumps

Will I still have the same degree of control over the pressure, as I want to do exponential pressure curves & linear ramping, etc

http://users.rcn.com/erics/ · by **erics** on Thu Dec 10, 2009 10:55 pm

Pls enlighten me on gear pumps

See page 3 of the link I originally provided. Sometimes, it helps to use this site's search engine

If it were me (and it's obviously not) rebuilding two Lineas, I would CONSIDER making a rather insignificant investment in a 220-240vac vibe pump to prove out the machine's fully before engaging into a substantial investment in pump's and controls.

by **pdx** on Fri Dec 11, 2009 12:20 am

Rosscopico0 wrote:Pls enlighten me on gear pumps

Will I still have the same degree of control over the pressure, as I want to do exponential pressure curves & linear ramping, etc

They are what LM are using in the Strada for that pressure control, plus by counting revolutions of the motor you have a pretty good flowmeter. Its a better solution for sure, at a third the cost.

by **Rosscopico0** on Fri Dec 11, 2009 9:40 am

Hmmmmmm, very interesting!!

Sometimes, it helps to use this site's search engine

Silly me, I used google!

So to check Ive got this right, the flow rate & the pressure vary proportionally to the input voltage?

by **Billc** on Sun Dec 13, 2009 1:35 am

If you insulate, only insulate the steam boiler. Since you will be adding Temp controls (PID), you will need the heat loss from the boiler to get the temp controller to function properly. A little insulation is OK but not greater than about 1/8 inch.

For the gear pump, these things are great. Essentially it depends upon what kind of motor you are using, but with a brushed DC motor you can either vary the voltage or send a PWM signal to it to control the speed of the motor. The speed controls the flow rate. Since pressure is directly dependent upon flow rate it also controls pressure. Another cool thing about gear pumps is that they are pretty accurate (as good or better than a flow meter). This means that you can also use the gear pump as a flow meter.

If you are using this on a 2 group you will only be able to use one group at a time.

bill

by **Rosscopico0** on Sun Dec 13, 2009 10:35 am

Thanks for the advice Bill!

If you are using this on a 2 group you will only be able to use one group at a time.

Ive been thinking about this for a few days, Im assuming the only way around this is 2 separate brew boilers, each with a dedicated pump??

Sounds like it could be done on a 4 group with its 2 brew boilers.

Well my 2 Lineas arrive on wednesday, PID has been ordered along with other bits & pieces, so will be able to get started straight away.

by **Rosscopico0** on Sun Dec 13, 2009 5:10 pm

If I use a Scace device to calculate margin of error & to calibrate the pressure profiling system once installed, I figure I can use a high sensitivity pressure transducer mounted in the boiler between the group heads.

From what I remember of hydraulics, I think that the pressure at the brew boiler should be very close to what is at the group head???
Or should I be fitting a pressure transducer to each group head for more accurate readings?

The analog output of the pressure transducer can be fed to an AD converter which in turn feeds digital data to my computer.
Using software I can enter the margin of error of the transducer based on the data from the Scace device & output that to a digital readout mounted on the front of the machine.

Using temp transducers mounted in each group head & AD converters, I can also do the temp calibration with the Scace device & enter margin of error as well.

by **Rosscopico0** on Mon Dec 14, 2009 12:32 pm

Well I found some thermometers with an output that I can send to a microcontroller. SYL-1812XA
I also found some RTD pipe plug probes with 1/4" & 1/8" NPT fittings. The probes only stick out about 1/2" so I should be able to mount them in the gooseneck very close to the group head.

Currently looking for a decent pressure transducer with a update maybe every 250mS.
Can anyone tell me if I need the pressure transducer very close to the group head or can I get away with having it between the group heads, on the brew boiler??

by **Billc** on Tue Dec 15, 2009 11:27 am

OK, the placement of the pressure transducer is of great concern. i am glad you are having this discussion. Everytime the water passes through an orifice or goes through a tube there is some pressure loss. If the orifice is small enough it can cause some dampening effect (or delay reaction). This is why it is important to have the transducer as close to the brew head as possible. I can't remember if you are using the group caps that have the flow meter and valve attached or not. If not then the best and easiest place to mount the pressure transducer is just before the 3 way valve. After the valve would even be better but you run the risk of coffee grounds in the transducer. If you are using the group cap with the valve attached then you can drill into the valve and mount it there.

For the 2 group you would need separate boilers for this. You could use 2 GS3 boilers. This is the method LM will use for the Strada and also has started on some other machines for the past year or so. Also with a bit of circuitry you should be able to use the standard LM probe or any other with a microcontroller. What brand of microcontroller are you using?

Bill

by **Rosscopico0** on Wed Dec 16, 2009 5:11 pm

Thanks for your advice Bill!

Ive been shopping around for pressure transducers & Im starting to think I would be better off getting a Scace II device to tune the PWM outputs to the motor & displaying the pressure as a function of pump voltage.
Unless anyone can suggest a source for inline pressure transducers (I was thinking of measuring the pressure before the pump, as well as at the group heads
I would save some money & I could use it to set up the 2nd machine as well, for no extra cost.

Machines are supposed to be arriving today, so will be able to tell you about the group head valves & flowmeters hopefully soon.

I figure that Ill do it as a single boiler version first, which gives me time to source some GS3 boilers (have emailed espressoliquidators & marzoccoman).

Im planning on using an Arduino Mega board. Lots of I/O, multiple PWM outputs that I can amplify for gear pumps. Ill build a prototype on breadboard first then etch some PCB's once tested & working. I would like to connect it to a 128 x 64 LCD, so I can display extraction time, group head temp, pressure & a graphic of the pressure curve selected. Also I will use a pot for an analog input to help initially tune the system & to do manual pressure control as well.

by **Rosscopico0** on Sat Dec 19, 2009 10:45 am

So, the hydraulics & solenoids are all assembled in the first machine (Thanks Todd for doing the cleaning for me!)
So Ill have to find myself a 220V supply soon so I can test if solenoids operate before I attach the original wiring harness.
Once I have a operating machine, I can start the modification process.
Heres a pic of the machine so far.....

by **Rosscopico0** on Fri Jan 15, 2010 12:52 am

Almost finished fitting the electronics.
Im using the original wiring harness, however I am replacing all crimp connectors.

Big thanks to Bill for sending me a wiring diagram to help me figure out where everything went!

Heres a pic of the machine at the moment

by **gscace** on Fri Jan 15, 2010 11:55 am

Sweet.

Dunno why I haven't been following this thread closely, but I have a few cents to toss into the hat.

First, I notice that your fb80 has Pierro group caps. Putting them on your Linea has a LOT of bang for the buck, and would be my first choice in Linea mods over pressure profiling. The mod is particularly effective on AV Lineas because the group solenoids and flowmeters are unheated in the stock configuration, which means that the Lineas need big heating flushes when used in intermittent duty. Installing the Pierro caps gives the Linea +- 0.5 degree stability in all duty cycles - on the order of the GS3. The caps from LM are only for the welded groups, but I believe that Terry's folks at EPNW have a retrofit kit that allows you to put them on the old style groups.

Second - if you are intending to develop a profiling system for commercial service I suggest that you talk the the LM guys a lot. They have been working on alternatives to the TMFR that might be easily integrated into the Linea. Ask yourself the purpose of your project. If it's to learn a little about pressure profiling, then the path that Nicholas took (manual control of the TMFR pump) is a relatively cheap way out. If you are looking to develop a robust system that can operate in the commercial realm, then you should defer to existing equipment (LM) if possible. It's certainly possible to design and build your own automated and programmable system, but it's a pretty big project for a home guy, and when it fails in the commercial environment you're gonna have to be able to provide support pronto since livelihoods are on the line. That's very different from the home scene, in which a broken machine is merely an inconvenience.

PM me with specific questions if you wanna.

-Greg

by **Rosscopico0** on Sat Jan 16, 2010 4:22 pm

Hi Greg!,
Thanks for your input, Im honored to have 2 of the biggest hitters in the game weighing in on my thread!

I figure I will be doing the mods in stages & testing the machine in a commercial environment (my work) & having the work fb/70 as a backup in case.
I plan to do the mods in a few stages.
Currently the first one is the brew boiler PID (since the original brew boiler thermostat was damaged during removal).

Im wondering with the Piero caps mod, since I will be later replacing a lot (possibly all) of the control systems, if it is worthwhile converting the machine to an EE & doing the EE piero cap mod (Im assuming I will need EE group heads?)

Also as I want to install a pressure profile system, I intend having a failsafe system in place.
I figure that since a gear pump can run on either a PWM or varying voltage, I can run the microcontrolled profile system in parallel with a basic potentiometer controlled system, that I can set the pump pressure on & simply have inline switches on each system. So if the microcontrolled system fails, I can switch it off & switch on the basic system, adjust my pressure via the potentiometer if necessary & continue operating the machine.

Later on down the line, Im thinking of possibly using 2 gs/3 boilers ( 1 for each group) & running 2 PID controllers with separate profiling systems to use different coffees on the same machine, but thats a fair time away!

by **Rosscopico0** on Wed Jan 20, 2010 11:08 pm

The rebuild part of the process is almost complete. Just need to get a replacement pump cable (the insulation on the old one was falling apart), also waiting for some silicon wire for the solid state relay & a project box for the pid to arrive in the mail.
I found a significantly cheaper waterproof enclosure for the pid unit. Only catch is I have to cut the hole in the front, but $5.76 instead of $80 works for me.
So here is a couple of pics


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