Nurri Leva S.A.

What happens it you accidentally vent the group

I’ve often though about this for both the nurri/Vostok

I know the kvdw has the lock

I’ve pondered that the vent on the nurri/vostok will be a limited size so it allows the arm not to ping back but come back slower is that the case

Cuprajake
The video of the Vostok releasing, albeit at the end of the shot so down around 6bar, shows the lever slowly rising up.
I agree that it must be an appropriatly small vent.
I reckon the Nurri would be similar.

The nurri’s venting merely causes the lever handle to rise slowly at a safe pace. Whether this is done by the controlled rate of water release or by a servo mechanism I do not know, but the release motion is very smooth and entirely safe and predictable. See this 2021 video for instance from about 1:44 onwards…

Just thinking aloud here, but… if the piston is full or partially full of water and the spring compressed… in order to decompress fully and the lever go all the way up in a split second, all the water needs to leave the piston immediately. If the venting hole is, say, 5mm in diameter (I don’t know how wide it is, but maybe it’s half of that!) he water will escape slowly, and consequently the lever won’t ever give you a kick in the teeth?

I could provide you with some mathematical formulae to calculate the flow rate and rate of decompression, but it would take me months as I’d need to re-read my physics books…. 🤣

Now, imagine what would happen if the portafilter on the group (54mm diameter hole) disengages all of a sudden… 😬

Cuprajake

Sorry are u referring to the what happens when the left paddle is actuated or what happens if the lever hamdle is pulled down on an empty portsfilter and then accidentally the lever handle is released ?

tompoland Hi Tom, thank you for sharing. I liked the video very much, the Western music was a nice touch 😀. I am sure you have seen it, but it is ironic (and might be a bit negligent) to have such a technology beast and the coffee coming out to be so thin. I would expect something viscous to come out down the spouts.
I wonder how this machine can be serviced but by a qualified engineer. I doubt they will go for a single group, as most likely not many would go for it, as I suspect it would be cost prohibitive for home use.
It seems the lever trend goes from strong to stronger. Happy days 😀

yeah accident,

so pull the lever down, infuse press wrong paddle/button and vent the group

i too think it will be a vent hole size to allow only so much flow

Cuprajake

If the lever is pulled down and water fills the grouphead, this must mean that there is a portwfilter locked in with ground coffee inside to provide the backstop to have that pressurised state. Because otherwise water will just flow straight into the drip tray and the grouphead cannot fill up. If that is the case and if the left paddle is accidentally pulled, then the nurri lever arm will safely rise and the grouphead will vent.

Having said that, I cannot envision a situation where the left paddle can accidentally be pulled. The paddle is quite high up on the groiphead and one’s hand is usually never anywhere near the paddle at any time unless one wants to actuate it. On top of that the action is pulling and not pushing and so that is rvne more difficult to do accidentally or so it appears to me…

Cuprajake

Classic Darwin Award winner.

tompoland

The aesthetics of the slim jim look better than a lot of other lever machines that’s for sure. However I may be nitpicking but it does not seem to be as cohesive design wise as it could have been especially when compared to my favourite KvDW design, the original Speedster with all the embossed circles. This is all subjective of course and it still looks better than most of the espresso machines out there of any type…

Yeah I know just thinking out loud about the feature not the machine,

As its something I can see coming to more modern levers as they progress

Like was say now on the vostok, prob work it’s way to the Evo too,

Easiest way to check what it does is to choke the lever and press the paddle , any volunteers 🤣

I think we all presume the same thing.

I’ve only let go of a lever once in my life on the londinuim, I does make you think haha

It seems to me that the best solution to make levers safe is what LSM did, basically a one-way damper which limits the speed at which the lever can move upwards. This way, whenever pressure is drops quickly in the brew chamber, voluntarily or accidentally, nothing serious happens. I presume LSM has a patent on this idea unfortunately, as implementing it can be done fairly easily using various approaches (yes, this might change the aesthetics slightly and add a few parts, but not that much)

Cuprajake asiest way to check what it does is to choke the lever and press the paddle , any volunteers 🤣

I already answered this in post 111.

Viernes The release paddle was created to end the shot, the possibility to backflush a lever and also vent pressure in case of choking and avoid portafilter sneezing which splashes hot water.

Lever goes back smoothly to the start position.