Converting Hydro Press to Air Pressure

[winters...@gmail.com]

Is it possible/practicable to convert a hydro press to run on air pressure instead of using so much water?  Any issues or pointers would be appreciated.  I know of a local winery that has done so.

[Claude Jolicoeur]

Grifo in Italy makes both pneumatic and hydro. From the image the outside of both presses are similar, but I don't know if they use the same bladder...
See the catalog : http://www.grifomarchetti.com/en/company
Claude

[Thomas Fehige]

I read that people have done so, but also read dire warnings against it. They ran along the lines that air is infinitely more elastic than water, so that when a bladder bursts the air will expand a lot, kind of explode with a big bang, while the water won't. I guess if you ask the manufacturer, they'll strongly advise against it.

On the other hand, with a small pump (e.g. something like this one) and a blue oak barrel or similar you could re-use the water. It would also include a means to regulate water pressure for a gradual increase of the pressure on the pulp.

Cheers -- Thomas

[HappyDogFarm]

I agree that using compressed air instead of water is fraught with danger if there is a failure, and I would never recommend it or be a party to it.  Better to create a closed system using a water reservoir (IBC) and an electric water pump.  Your consumption of water is zero once you fill the reservoir, and an electric pump can offer you a higher operating pressure than you might be getting from your municipal supply.  A common well pressure switch can be used to prevent applying excess pressure.

[Dick Dunn]

On Mon, Aug 22, 2016 at 12:16:21PM -0700, HappyDogFarm wrote:
> I agree that using compressed air instead of water is fraught with danger
> if there is a failure, and I would never recommend it or be a party to it.

seconded!

but...

> Better to create a closed system using a water reservoir (IBC) and an
> electric water pump. Your consumption of water is zero once you fill the
> reservoir, and an electric pump can offer you a higher operating pressure
> than you might be getting from your municipal supply. A common well
> pressure switch can be used to prevent applying excess pressure.

The couple of hydraulic bladder presses I know about have their own pressure
cut-offs, and were around 3 bar, 40-45 psi. So that's actually lower than
municipal supplies at least around here.
--
Dick Dunn rc...@talisman.com Hygiene, Colorado USA

[Thomas Fehige]

Am Montag, 22. August 2016 23:06:10 UTC+2 schrieb Dick:

...

> Better to create a closed system using a water reservoir (IBC) and an
> electric water pump.  Your consumption of water is zero once you fill the
> reservoir, and an electric pump can offer you a higher operating pressure
> than you might be getting from your municipal supply.  A common well
> pressure switch can be used to prevent applying excess pressure.

The couple of hydraulic bladder presses I know about have their own pressure
cut-offs, and were around 3 bar, 40-45 psi.  So that's actually lower than
municipal supplies at least around here.

Not sure if Speidel's presses have an automatic cut-off valve, but Speidel, too, prescribes 3 bar max.

Anyway, the advantage of regulating water pressure is that you can decrease the pressure. For a difficult pulp it makes sense to press more slowly. Of course you can do that by opening and closing the tap repeatedly, but if you can adjust the pressure itself you can leave the press alone and do something more exciting than opening and closing a tap again and again ...

Cheers -- Thomas

[winters...@gmail.com]

So using water with your own recapture in, say an IBC tote, how do you regulate the pressure?  Do you install a valve and gauge in the line somewhere?

[HappyDogFarm]

Water pressure regulators are available from irrigation supply companies.  A flow rate (volume) regulator can also be installed to control the rate of squeeze.  I don't have a hydro press, but I do have a drip irrigation system.    Here are examples of regulators available here in the States.  For example: I limit the pressure to my irrigation manifolds to 30 psi (approx 2 bar) to be gentle on my emitters.

ay

[Barrett Froc]

You're absolutely right.

 

Just for some information, municipal water supplies are regulated to run at minimum 80 psi out of the water treatment plant, and environmental/health regulations stipulate that if you're on a pressurized system (ie, not a rural drip system) that the pressure in the pipelines outside your house shouldn't be lower than 12 psi, but most municipalities aim for 40-60 psi delivered. One loses a little pressure through the meter (if you have one) but really, the biggest pressure loss you should be seeing in a hydraulic system is non-rigid pipe, usually in the form of garden hose. If one wants more pressure, shorten the hose is usually the best advice.