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Pre-infusion & the Silvia

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  • Dimal
    replied
    Re: Pre-infusion & the Silvia

    Originally posted by vicroamer link=1210326237/20#37 date=1213821905
    I think it would need to be plumbed in after the three way valve for the latent pressure to be dumped into drip tray when brew switch is turned off, as you say all good fun.
    Dont think thats necessary, or even practical vr.... With an accumulator (which this is in effect), you would be much better off to install this as close to the pump as possible. Any latent pressure stored by the accumulator circuit would be exhausted via the Group and PF circuit once the PF is removed and the Group flushed briefly. This wouldnt normally create an additional step to the process though as pretty well all CSers would flush out the Group and the PF after pulling a shot to clean out all signs of coffee particles, etc.

    Trying to install downstream of the 3-Way Valve would be much more complex (if even possible) and, as you say, introduce another heatsink path away from the Boiler which is obviously not desirable. Just looking at where the 3-Way is located on the Silvia (and lots of other machines for that matter) it seems to be integrated into the Group Head and the brew-path galleries therein so would require a fair amount of modification to the existing design in order to incorporate the accumulator circuit here.

    Anyway, its all very interesting and probably worth giving a go for someone with access to all the necessary tools, fittings and what have you. Ill stick with the Gicleur system on my Bezzera, works quite effectively and its characteristic is easily modified if ever I decide it is required. All the best mate ,

    Mal.

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  • vicroamer
    replied
    Re: Pre-infusion & the Silvia

    Local shock arrestors look to have the same internal pressure as the ones used so that part is ok. I was a bit concerned the extra piping and water might heatsink some group heat away but I dont think theres enough there to worry about. I think it would need to be plumbed in after the three way valve for the latent pressure to be dumped into drip tray when brew switch is turned off, as you say all good fun.

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  • Dimal
    replied
    Re: Pre-infusion & the Silvia

    Yep,

    That would work fine vr.... If youre up for the challenge to do as neat a job as that chap did. Unless you can grab exactly the same W-H Arrestors as he did though, youd be up for a bit of experimentation. Not that that is a bad thing though, all adds to the fun....

    Mal.

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  • vicroamer
    replied
    Re: Pre-infusion & the Silvia

    I came across the link below over on CG, thought it relevant to this thread and CSs might like to discuss pros and cons of doing this mod.
    http://www.coffeegeek.com/forums/esp...inemods/373954

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  • Randy_G.
    replied
    Re: Pre-infusion & the Silvia

    Originally posted by Mal link=1210326237/30#33 date=1211044273
    To be honest Randy,
    I think if someone wants this sort of characteristic from their machine, theyd be a lot better off buying something that is manufactured that way. Playing around with electrics is one thing (fitting PID Control for example) but trying to modify the hydraulic circuit is a whole different kettle of fish in my opinion,Mal.
    I agree completely. I approached it on a theoretical level, but I do know of folks who have added three PIDs to a Silvia! (Input temperature control after the external rotary pump(iirc), PID for boiler temp, and a PID controlled brewhead heating cable.)

    One thing that is often overlooked when doing such mods is that there is a lot more going on than just temperature control in the better machines. I learned that when going from Silvia to the VBM Domobar Super. Water delivery rates, water delivery patterns, and more all are part of the equation. The espresso is now decidedly better, but I cant say that the coffee is three times better now (cost comparison Silvia:VBM), but I can say that the consistency is far better than the cost would reflect.

    With a newer Silvia with the adjustable OPV, I would recommend the addition of a brew pressure gage and a PID. Beyond that, invest in a better machine... IMO.

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  • Dimal
    replied
    Re: Pre-infusion & the Silvia

    To be honest Randy,

    I think if someone wants this sort of characteristic from their machine, theyd be a lot better off buying something that is manufactured that way. Playing around with electrics is one thing (fitting PID Control for example) but trying to modify the hydraulic circuit is a whole different kettle of fish in my opinion,

    Mal.

    Leave a comment:


  • Randy_G.
    replied
    Re: Pre-infusion & the Silvia

    Originally posted by Mal link=1210326237/30#31 date=1211036374
    I spose you could fit the Gicleur elsewhere in the high pressure circuit downstream of the Pump but then this would affect other aspects of the Silvias operation, not just the brew cycle.....Mal.
    You are correct in thinking that the Gicleur has to go into the brewhead somewhere. Silvias PLV is mounted on the boiler. The gicleur has to be downstream of the PLV, so putting it anywhere before the boiler also puts it before the PLV and would stress the pump and also limit the usefulness of the hot water valve.

    it might be possible to put something wither above the shower and shower head (not likely), or possibly on the output tube leading to the brewhead inside the boiler.

    Leave a comment:


  • Dimal
    replied
    Re: Pre-infusion & the Silvia

    With regard to Vibe Pumps on machines like the Silvia with the added protection of a Pressure Limiting Valve (PLV), the fitment of a Gicleur into the Group Head structure somewhere (if this is possible or not, I have no idea) it would not cause any harm to the Pump at all due to the existence of the PLV. This is after all, the primary purpose of the PLV, to protect the Pump.

    I spose you could fit the Gicleur elsewhere in the high pressure circuit downstream of the Pump but then this would affect other aspects of the Silvias operation, not just the brew cycle.....

    Mal.

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  • vicroamer
    replied
    Re: Pre-infusion & the Silvia

    Further to previous post.
    A difference I noticed between Silvia and the Unic is that the gicleur equipped Unic has a slower pour, despite its big motor and rotary pump.

    Leave a comment:


  • vicroamer
    replied
    Re: Pre-infusion & the Silvia

    From a reply from Dan Kehn over on HB re a HX machine.
    In the guide, I refer to the preinfusion of your model (and the semi-auto like mine) as progressive preinfusion because it relies on the gicleur (orifice) and vibe pump for slower pressure ramp up as compared to a "true" E61:
    He was not referring to the Silvia but to a HX machine but I believe it is relevant re preinfusion, as to applying it to Silvia I dont know but Mark Prince did comment Silvias pour is quicker because it lacks a flow restrictor.

    Leave a comment:


  • Dolcimelo
    replied
    Re: Pre-infusion & the Silvia

    Originally posted by vicroamer link=1210326237/15#27 date=1210974808
    With a vibe pump, you cant really be gentle - its either on or off
    According to everything I have read about vibe vs rotary the vibe pump has a more gradual ramp up than the rotary. Some machines rely on the flow restriction of the gicleur combined with the vibes ramp up characteristics, for a softer  infusion.
    Very interesting vicroamer. So the restrictor isnt bad for the pump? I guess theyre pretty resilient. In that case, perhaps it would be possible on any vibe machine, if you could get a gicleur into the line. That is, if you still think its worth it...

    matt

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  • vicroamer
    replied
    Re: Pre-infusion & the Silvia

    With a vibe pump, you cant really be gentle - its either on or off
    According to everything I have read about vibe vs rotary the vibe pump has a more gradual ramp up than the rotary. Some machines rely on the flow restriction of the gicleur combined with the vibes ramp up characteristics, for a softer infusion.

    Leave a comment:


  • Dolcimelo
    replied
    Re: Pre-infusion & the Silvia

    Originally posted by JavaB link=1210326237/15#19 date=1210749251
    Matt,

    Ive got them on the La Cimbali as well....

    But there is a bit more involved.....

    Mains pressure is at 3.5 Bar (at rest).....

    Press start...... the 3 way opens.... 3.5 bar is applied to the puck (via the 0.8mm restriction)..... shortly thereafter the rotary pump starts..... and pressure is ramped up from 3.5 to 9 Bar during the pre-infusion phase (again via the 0.8mm restriction).....

    Bit hard to do that with the Silvia..... but I guess it could go from zero to 9 Bars.... :-/ but would it be as gentle?
    No, I guess not JavaB. With a vibe pump, you cant really be gentle - its either on or off, and restricting it is probably bad for the pump. Anyway, I doubt that pre-infusion is going to be the main factor in making a good espresso on the Silvia. She seems to encourage people to mod (maybe something about the build?) but she is really a fine gal as she is. I really agree with Mal that the PID is probably the only mod that will really make a difference - except modding your technique. And even then, I suspect its more for convenience and consistency than anything else.

    matt

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  • griffster
    replied
    Re: Pre-infusion & the Silvia

    Originally posted by Mal link=1210326237/0#6 date=1210400855
    Originally posted by fix link=1210326237/0#5 date=1210368937
    if you want to manually preinfuse, turn of coffee switch after 2-3 sec, turn backon after another 2-3 sec
    graham
    Only problem with this method though Graham, is that the 3-Way Valve will instantaneously bleed off any water under pressure along with coffee extraction. I think its a lot better to just use the Silvia as its designed, you wont lose any coffee that way......

    Mal.
    Not only that but wouldnt turning the switch on without the valve being open just let the water hit the grind at full pressure? Someone mentoned this as being a pre-slam. ;-)

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  • gregpullman
    replied
    Re: Pre-infusion & the Silvia

    Yep youll definitely get better results from a warm Silvia than a cold one, no disputing that.

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