Pressure profiling with a bypass valve - Page 3

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EricL

#21: Post by EricL »

dsc wrote:Hi guys,

I got the bits today and will be testing out the manual operation after work. The only thing I'm a bit worried is the ball valve itself which seems to be lubricated with some rather smelly grease/oil. Do you think it's going to be a problem, ie. the water is going to taste different when passing the valve? I'd say no as it is hot/cold water approved, but maybe I should switch to something more food safe?

Regards,
dsc.
At the very least you should make yourself sign a waiver before consuming any espresso from the machine. :shock:
Personally, I would go for more food safe

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AndyS

#22: Post by AndyS »

dsc wrote:I got the bits today and will be testing out the manual operation after work. The only thing I'm a bit worried is the ball valve itself which seems to be lubricated with some rather smelly grease/oil. Do you think it's going to be a problem, ie. the water is going to taste different when passing the valve?
I wouldn't use it until you are able to thoroughly clean the valve (via flushing or if possible, disassembly).
-AndyS
VST refractometer/filter basket beta tester, no financial interest in the company

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dsc (original poster)

#23: Post by dsc (original poster) »

Hi guys,

it's all ok, the valve isn't greased, it uses a round teflon 'washer' which presses against the ball and makes it water tight. I put everything together last night and it does work, but sadly I'm getting water leaks here and there and will have to use a few different fittings before using it again.

Regards,
dsc.

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AndyS

#24: Post by AndyS »

dsc wrote:smelly grease/oil
Your concern reminds me: one thing that I don't believe has been mentioned much is "new machine taste/odor."

In the world of automobiles, "new car smell" is a positive. I believe there are even aerosol products designed to give your 100,000 mile beater that "just-out-of-the-showroom" aroma.

But for espresso machines, it's definitely NOT desirable. On the rare occasions when I've taken possession of a brand new machine, it's generally taken several hundred shots to get the oily and/or metallic tastes to fade.

This obviously makes a "first look" type of machine review more problematic.
-AndyS
VST refractometer/filter basket beta tester, no financial interest in the company

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HB
Admin

#25: Post by HB »

AndyS wrote:This obviously makes a "first look" type of machine review more problematic.
Water reservoirs are the worst. Running them through the dishwasher several times helps. I avoid it by rerouting the inlet hose to a water jug placed next to the machine.
Dan Kehn

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dsc (original poster)

#26: Post by dsc (original poster) »

Hi guys,

well as Greg said earlier it works, but:

- I will have to use a smaller ball valve as the one I have now let's too much water through and it's hard to adjust the pressure

- to make the whole thing smaller I will have to use smaller pipes/tubes/ fittings

- with a broken pressure gauge on my Elektra I had to watch a pressure gauge that was stuck just after the tee with the valve and so it was hard to adjust the valve, watch the pour and watch the pressure changes

- I will have to buy a new pump as the one I have is rather noisy (it was like that before)

Here's a short clip showing how it all looks like:

http://vimeo.com/3174090

The concept is simple and with a proportional valve it can be quite easy to control pressure, but it's still a pain to connect everything together. I will try to get a 3/8" ball valve and some fittings to go with it.

Regards,
dsc.

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hbuchtel

#27: Post by hbuchtel »

Nice!

Maybe putting a long handle on the valve would make it easier to control. You could mount it on the machine so adjusting it was like playing a slot machine in Vegas :D



Regards, Henry
LMWDP #53

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dsc (original poster)

#28: Post by dsc (original poster) »

Hi guys,

I'm pretty sure that I will remove the pump/motor from the machine and mount it under the kitchen sink, thus giving myself a bit more space for all the additional piping.

With the pump partially dead (noisy) I started thinking whether it's possible to damage the pump by using this kind of bypass? It's true that the pump was a bit faulty before but now it has gotten rather noisy and I'm curious what's the cause of it.

Regards,
dsc.

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AndyS

#29: Post by AndyS »

dsc wrote:With the pump partially dead (noisy) I started thinking whether it's possible to damage the pump by using this kind of bypass?
Not by the bypass itself. After all, the rotary vane pumps used in espresso machines have a similar built-in bypass.

The pump could be damaged if particulate matter is allowed to enter the inlet. This sometimes happens accidentally when plumbing is modified.
-AndyS
VST refractometer/filter basket beta tester, no financial interest in the company

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dsc (original poster)

#30: Post by dsc (original poster) »

Hi everyone,

I just finished writing the software for the pressure profiling system and I'm now waiting for the hardware bits (stepper motor and elements to put together a power supply for it). To bore you a little bit and update this topic I thought I would explain how it's all going to work.

The PPS (pressure profiling system) will offer the following functions:

- full Manual mode in which the user can open/close the valve as much as he/her likes, adjusting the pressure within a range of 2-9bar. Control of the valve will be possible via a mom-off-mom toggle switch on the control box. Keeping the switch in the 'up' position will close the bypass valve thus increasing pressure and keeping the switch in the 'down' position will open the valve and decrease the pressure on the group. The 'pump on' signal won't affect the valve control in any way which means you can adjust the valve with the pump engaged or not.

- full Auto mode in which a predefined pressure profile is being executed when the 'extraction' button on the front of the machine is pressed. The system offers three custom set pressure profiles (see Programming mode) and one Default profile which is a 'preinfuse for 3s at 2bar - ramp up to 9bar in 3s - ramp down to 6bar within 21s'.

- Programming mode in which the user can set his/her own profile (via manual mode) and save it under one of the profile buttons (three buttons are available labled P1, P2 and P3). The buttons are the normal push-to-make momentary type and allow to both save (long press) and load (short press) previously configured profiles.

Switching between the Auto/Man mode is possible via an on-on toggle switch and Programming mode can be turned on/off via a mom-off-mom toggle switch to eliminate accidental activations. The control box also has 4 red LEDs to show which profile is active at the moment and 2 green LEDs for 'Pump On' and 'Programming On' indication.

Here's a drawing which shows how the faceplate of the control box will look like (it doesn't show the Programming ON LED):

Image

Hopefully the whole thing should be working before the end of April.

Regards,
dsc.